**ETIOPATHOGENESIS OF PERIODONTAL DISEASE ** Dr. Pradeep Koppolu BDS, MDS (Perio), PhD (Malaysia), FICOI, FPFA, PDCR Discipline Lead & Program Convenor Periodontics and Implantology Dr. Pradeep Koppolu BDS, MDS (Perio), PhD (Malaysia), FICOI, FPFA, PDCR Discipline Lead & Program Convenor Periodontics and Implantology The University of Western Australia institutional logo featuring the university crest and name. • Is Human foetus inside the uterus **sterile**? • Within **2 weeks**, a nearly mature microbiota is established in the gut of the newborn baby. • After **weaning (>2 years)**, the entire human microbiota is formed and comprises a very complex collection of hundreds of different types of bacteria with approximately **10¹⁴ microbial cells**. • From this moment on, our body contains **1.3 to 10 times** more bacteria than human cells. • It has been estimated that, for a normal, healthy human being, the bacterial population comprises **2 kg of the total body weight**. This is fascinating if one realizes that the average human brain weighs only about 1.4 kg.  - Is Human foetus inside the uterus **sterile**? - Within **2 weeks**, a nearly mature microbiota is established in the gut of the newborn baby. - After **weaning (>2 years)**, the entire human microbiota is formed and comprises a very complex collection of hundreds of different types of bacteria with approximately **10¹⁴ microbial cells**. - From this moment on, our body contains **1.3 to 10 times** more bacteria than human cells. - It has been estimated that, for a normal, healthy human being, the bacterial population comprises **2 kg of the total body weight**. This is fascinating if one realizes that the average human brain weighs only about 1.4 kg. A close-up photo of a newborn baby's hand and fingers on the right side of the slide, illustrating the context of fetal development or birth. *INTRODUCTION* • Within hours after birth sterile oral cavity is colonized by numbers of **mainly facultative and aerobic bacteria** • From **2<sup>nd</sup> day, anaerobic bacteria** can be detected • First and most dominant oral microbes in the oral cavity of newborn infants: <u>**Streptococcus salivarius and Streptococcus mitis**</u> • *Veillonella spp., Neisseria spp., Actinomyces spp. and Staphylococcus spp. are also among the first colonizers of the oral cavity* #### Introduction - Within hours after birth sterile oral cavity is colonized by numbers of **mainly facultative and aerobic bacteria**. - From **2nd day, anaerobic bacteria** can be detected. - First and most dominant oral microbes in the oral cavity of newborn infants: **Streptococcus salivarius and Streptococcus mitis**. - *Veillonella spp., Neisseria spp., Actinomyces spp. and Staphylococcus spp. are also among the first colonizers of the oral cavity.* University of Western Australia logo located in the top-left corner. - It is estimated that the oral bacterial microbiome of adults encompasses approximately **750 commonly occurring species**, roughly half of which can be present at any time in any individual. - A shift in microbial community leads to an **imbalance, or dysbiosis**, in the microbiota. - This **shift** in the microbial community can be largely independent of the acquisition of new members of the microbiota and instead reflects changes in the abundance of either individual organisms or consortia of organism's resident within the **subgingival bioflm (previously referred to as plaque)**. - It is estimated that the oral bacterial microbiome of adults encompasses approximately **750 commonly occurring species**, roughly half of which can be present at any time in any individual. - A shift in microbial community leads to an **imbalance, or dysbiosis**, in the microbiota. - This **shift** in the microbial community can be largely independent of the acquisition of new members of the microbiota and instead reflects changes in the abundance of either individual organisms or consortia of organism's resident within the **subgingival biofilm (previously referred to as plaque)**. The University of Western Australia **Temperature** **Atmosphere** **redox potential** **pH** **Host genetics**, health and **lifestyle** **Receptors for attachment** **Nutrients** **Host defenses** **Microbial interactions** **Composition and activity of oral microbiota** **NATURAL AND STABLE RESIDENT ORAL BIOFILMS** **BENEFICIAL FUNCTIONS TO THE HOST** **(b)** **Immunological** **ENVIRONMENTAL PERTURBATION** **Non-immunological** **Inflammation** **Integrity of host defenses** **Host genetics** **Systemic disease** **pH** **Diet** **Lifestyle** **Antibiotics** **Reduced saliva flow** **Composition and activity of oral microbiota** **RE-ARRANGEMENT OF COMMUNITY STRUCTURE** **INCREASED RISK OF DISEASE** Fig. 8-1 Host factors that influence the microbial composition, activity and stability of the resident oral microbiota. (a) A number of host factors help to determine the composition and activity of the natural and beneficial oral microbiota. (b) A perturbation in a key environmental factor can disrupt the natural stability (microbial homeostasis) of the resident microbiota at a site and result in a re-arrangement of the composition and activity of the resident microbial community; such a change might predispose the site to disease. (Source: Adapted from Marsh et al. 2011.)  #### Host Factors Influencing Oral Microbiota **Temperature** **Atmosphere** **redox potential** **pH** **Host genetics**, health and **lifestyle** **Receptors for attachment** **Nutrients** **Host defenses** **Microbial interactions** **Composition and activity of oral microbiota** **NATURAL AND STABLE RESIDENT ORAL BIOFILMS** **BENEFICIAL FUNCTIONS TO THE HOST** **(b)** **Immunological** **ENVIRONMENTAL PERTURBATION** **Non-immunological** **Inflammation** **Integrity of host defenses** **Host genetics** **Systemic disease** **pH** **Diet** **Lifestyle** **Antibiotics** **Reduced saliva flow** **Composition and activity of oral microbiota** **RE-ARRANGEMENT OF COMMUNITY STRUCTURE** **INCREASED RISK OF DISEASE** *Fig. 8-1 Host factors that influence the microbial composition, activity and stability of the resident oral microbiota. (a) A number of host factors help to determine the composition and activity of the natural and beneficial oral microbiota. (b) A perturbation in a key environmental factor can disrupt the natural stability (microbial homeostasis) of the resident microbiota at a site and result in a re-arrangement of the composition and activity of the resident microbial community; such a change might predispose the site to disease. (Source: Adapted from Marsh et al. 2011.)* A scientific diagram divided into two panels comparing stable vs. diseased states of oral microbiota. Panel (a) shows 'NATURAL AND STABLE RESIDENT ORAL BIOFILMS' as a central outcome of balanced host factors like temperature, pH, nutrients, and host genetics, leading to 'BENEFICIAL FUNCTIONS TO THE HOST'. Panel (b) illustrates how 'ENVIRONMENTAL PERTURBATION' (triggered by immunological or non-immunological factors) causes a 'RE-ARRANGEMENT OF COMMUNITY STRUCTURE', resulting in 'INCREASED RISK OF DISEASE'. Both panels feature arrows pointing from specific host/environmental factors toward the central microbiota box. The University of Western Australia **From an ecologic viewpoint, the oral cavity, which communicates with the pharynx, should be considered an “open growth system” with an uninterrupted ingestion and removal of microorganisms and their nutrients.** Any microorganisms that are **unable to adhere** to a surface within the **mouth are washed away** in the flow of saliva and **swallowed.** The composition and diversity of the microbial community is therefore **impacted by** physical gradients of **temperature, humidity, nutrient content, salivary flow, oxygen tension and pH, as well as shear forces due to mastication.** Frequent exposure to dietary sugars can significantly affect the dynamics of bacterial adhesion and accumulation.      **From an ecologic viewpoint, the oral cavity, which communicates with the pharynx, should be considered an "open growth system" with an uninterrupted ingestion and removal of microorganisms and their nutrients.** Any microorganisms that are **unable to adhere** to a surface within the **mouth are washed away** in the flow of saliva and **swallowed.** The composition and diversity of the microbial community is therefore **impacted by** physical gradients of **temperature, humidity, nutrient content, salivary flow, oxygen tension and pH, as well as shear forces due to mastication.** Frequent exposure to dietary sugars can significantly affect the dynamics of bacterial adhesion and accumulation. Background image showing a close-up of blue circuit board traces and electronic components. Flowchart node (orange box) defining the oral cavity as an 'open growth system' communicating with the pharynx, involving ingestion and removal of microorganisms. Flowchart node (white box with blue border) explaining that microorganisms unable to adhere are washed away by saliva flow and swallowed. Flowchart node (green box) listing physical gradients impacting microbial community composition: temperature, humidity, nutrient content, salivary flow, oxygen tension, pH, and shear forces from mastication. Flowchart node (purple box) stating that frequent exposure to dietary sugars affects bacterial adhesion and accumulation dynamics. The university of WESTERN AUSTRALIA •The constant lubrication of the oral cavity by saliva allows microbes to disperse and reach distant sites within the oral cavity, with **saliva** effectively acting as a **transport medium**. •Although saliva has antimicrobial properties, it has also been reported to **promote growth** of a **health-associated microbiota**. •The primary source of nutrients for the oral microbiome is provided by the host, and include the proteins and glycoproteins present in **saliva** and gingival crevicular fluid (GCF). •The mouth is maintained at a temperature of around **35–37 °C**, which is suitable for the growth of a broad range of microbes, though temperature **does increase at subgingival sites during inflammation**, which can favour the growth and metabolism of some putative periodontal pathogens. - The constant lubrication of the oral cavity by saliva allows microbes to disperse and reach distant sites within the oral cavity, with **saliva** effectively acting as a **transport medium**. - Although saliva has antimicrobial properties, it has also been reported to **promote growth** of a **health-associated microbiota**. - The primary source of nutrients for the oral microbiome is provided by the host, and include the proteins and glycoproteins present in **saliva** and gingival crevicular fluid (GCF). - The mouth is maintained at a temperature of around **35–37 °C**, which is suitable for the growth of a broad range of microbes, though temperature **does increase at subgingival sites during inflammation**, which can favour the growth and metabolism of some putative periodontal pathogens. The University of Western Australia institutional logo located in the top-left corner. • **pH** is a major determinant of bacterial distribution and metabolism in the mouth. • The **buffering activity of saliva** plays a major role in maintaining the intraoral pH at around neutrality, which favours the growth of the resident oral microbiome. • The pH in dental biofilms falls rapidly to below **pH 5.0** following the intake of **dietary sugars** due to the production of **acidic fermentation products** (Marsh et al . 2016b). • Many **health- associated bacteria** can tolerate brief conditions of **low pH** but are inhibited or **killed** by more frequent or prolonged exposures to **acidic** conditions (Svensater et al . 1997). • The mouth is richly endowed with components of both the innate (e.g. lysozyme, lactoferrin, sialoperoxidase, host defence peptides, etc.) and adaptive (**secretory IgA, IgG, complement, neutrophils, etc.**) immune response (Marsh et al . 2016a, b) - **pH** is a major determinant of bacterial distribution and metabolism in the mouth. - The **buffering activity of saliva** plays a major role in maintaining the intraoral pH at around neutrality, which favours the growth of the resident oral microbiome. - The pH in dental biofilms falls rapidly to below **pH 5.0** following the intake of University of Western Australia logo in the top-left corner. The oral microbiome Sedghi L, DiMassa V, Harrington A, Lynch SV, Kapila YL. The oral microbiome: Role of key organisms and complex networks in oral health and disease. Periodontol 2000. 2021;87:107–131 **Life stage** **Oral microbial diversity** **Factors** **Maternal transmission** **Genetics** **Oral hygiene practice** **Dietary habits** **Smoking** **Environmental factors** **Stress** **Medications** **Systemic diseases/conditions** **Periodontology 2000** SEDGHI ET AL. WILEY 111 **High** **Low** FIGURE 1 **The Oral Microbiome: From First Encounters to Lifelong Encounters**. _**Prenatal**_. The prenatal oral cavity is thought to be sterile until birth, with colonization occurring soon after delivery. The composition of the oral microbiota in infants has been shown to correlate with mode of delivery. However, infants share an oral microbiota similar to that of their mothers, suggesting that the infant oral microbiota may derive from hematogenous or intrauterine transmission from the mother. Detection of oral microbes of maternal origin among several intrauterine locations, as well as associations with adverse pregnancy outcomes, demonstrate the role of the maternal oral microbiome in prenatal health and suggests in utero colonization. _**Early life**_. Microbial colonization begins shortly following birth through vertical transmission from the mother, transmission from the diet, and transmission from infant-to-human interactions. Microbial diversity increases upon eruption of primary teeth as this process permits the expansion of microbial niches in the oral cavity. Eruption of primary teeth also results in deviation from the maternal oral microbiota. As children age, their oral microbiotas begin to stabilize. _**Adult life**_. The oral microbiota continues to be shaped throughout life by genetic and environmental factors. Environmental factors that influence the composition and function of the oral microbiome include diet, stress, oral hygiene practices, drinking alcohol, and smoking. Genetic factors are linked to conserved phylogenetic and functional microbial signatures related to development of dental caries and heritable predisposition to periodontal disease. _**Aging and systemic disease**_. Oral microbiome diversity has been shown to decrease with age. The phylogeny and functional signatures of the oral microbiome are  The oral microbiome Sedghi L, DiMassa V, Harrington A, Lynch SV, Kapila YL. The oral microbiome: Role of key organisms and complex networks in oral health and disease. Periodontol 2000. 2021;87:107–131 **Life stage** **Oral microbial diversity** **Factors** **Maternal transmission** **Genetics** **Oral hygiene practice** **Dietary habits** **Smoking** **Environmental factors** **Stress** **Medications** **Systemic diseases/conditions** **Periodontology 2000** SEDGHI ET AL. WILEY 111 **High** **Low** FIGURE 1 **The Oral Microbiome: From First Encounters to Lifelong Encounters**. _**Prenatal**_. The prenatal oral cavity is thought to be sterile until birth, with colonization occurring soon after delivery. The composition of the oral microbiota in infants has been shown to correlate with mode of delivery. However, infants share an oral microbiota similar to that of their mothers, suggesting that the infant oral microbiota may derive from hematogenous or intrauterine transmission from the mother. Detection of oral microbes of maternal origin among several intrauterine locations, as well as associations with adverse pregnancy outcomes, demonstrate the role of the maternal oral microbiome in prenatal health and suggests in utero colonization. _**Early life**_. Microbial colonization begins shortly following birth through vertical transmission from the mother, transmission from the diet, and transmission from infant-to-human interactions. Microbial diversity increases upon eruption of primary teeth as this process permits the expansion of microbial niches in the oral cavity. Eruption of primary teeth also results in deviation from the maternal oral microbiota. As children age, their oral microbiotas begin to stabilize. _**Adult life**_. The oral microbiota continues to be shaped throughout life by genetic and environmental factors. Environmental factors that influence the composition and function of the oral microbiome include diet, stress, oral hygiene practices, drinking alcohol, and smoking. Genetic factors are linked to conserved phylogenetic and functional microbial signatures related to development of dental caries and heritable predisposition to periodontal disease. _**Aging and systemic disease**_. Oral microbiome diversity has been shown to decrease with age. The phylogeny and functional signatures of the oral microbiome are A labeled conceptual diagram illustrating the development of the oral microbiome across different life stages and its influencing factors. The upper portion displays a horizontal timeline of human silhouettes representing 'Life stage' from left to right: an embryo/fetus (green), infant crawling (green), child running (blue), adult walking (yellow), older adult walking (orange), and elderly person with a cane (brown). A vertical axis on the right indicates 'Oral microbial diversity', ranging from Low to High, showing that diversity increases as life progresses through these stages. The lower section is titled 'Factors' and categorizes influences into specific groups: - Maternal transmission: Illustrated by a uterus containing a fetus and a DNA double helix. - Genetics: Represented by a DNA strand. - Environmental factors: Grouped together and illustrated with icons for Oral hygiene practice (toothbrush), Dietary habits (pizza slice, milk bottle, burger), Smoking (cigarette), Stress (face with skull symbols), and Medications (pill). - Systemic diseases/conditions: Illustrated by a full-body anatomical figure highlighting internal organs. The Oral Cavity From a Microbe’s Perspective Buccal mucosa Streptococcus spp., Haemophilus spp., Gemella spp. Gingiva Streptococcus spp. (*S. mitis*) Palate Streptococcus spp., Veillonella spp., Prevotella spp., Actinomyces spp. Tongue dorsum Streptococcus spp. (*S. salivarius, S. parasanguinis*), Veillonella spp. (*V. parvula*), Prevotella spp. (*P. intermedia*), Actinomyces, Granulicatella adiacens Supragingival biofilm Streptococcus spp. (*S. mitis, S. sanguinis, S. gordonii, S. oralis, S. constellatus*), Actinomyces spp., Capnocytophaga spp., Corynebacterium spp. Subgingival biofilm Streptococcus spp., Peptostreptococcus spp., Fusobacterium spp., Capnocytophaga spp., Prevotella spp., Actinomyces spp., Corynebacterium spp., Treponema spp., Porphyromonas spp., Aggregatibacter actinomycetemcomitans  The Oral Cavity From a Microbe’s Perspective Buccal mucosa Streptococcus spp., Haemophilus spp., Gemella spp. Gingiva Streptococcus spp. (*S. mitis*) Palate Streptococcus spp., Veillonella spp., Prevotella spp., Actinomyces spp. Tongue dorsum Streptococcus spp. (*S. salivarius, S. parasanguinis*), Veillonella spp. (*V. parvula*), Prevotella spp. (*P. intermedia*), Actinomyces, Granulicatella adiacens Supragingival biofilm Streptococcus spp. (*S. mitis, S. sanguinis, S. gordonii, S. oralis, S. constellatus*), Actinomyces spp., Capnocytophaga spp., Corynebacterium spp. Subgingival biofilm Streptococcus spp., Peptostreptococcus spp., Fusobacterium spp., Capnocytophaga spp., Prevotella spp., Actinomyces spp., Corynebacterium spp., Treponema spp., Porphyromonas spp., Aggregatibacter actinomycetemcomitans A composite medical figure displaying six labelled clinical photographs of oral anatomy. Each panel points to a specific ecological niche using a black line and lists the corresponding prevalent bacterial species found there. Top row (left to right): Buccal mucosa showing upper teeth and cheek tissue; Gingiva showing inflamed gum tissue; Palate showing the roof of the mouth and teeth. Bottom row (left to right): Tongue dorsum showing the tongue surface; Supragingival biofilm showing plaque on tooth surfaces above the gumline; Subgingival biofilm showing plaque below the gumline. From a microbiological viewpoint, **teeth and implants** are unique for **two reasons**: (1) They provide a hard, **non-shedding** surface that allows for the development of extensive structured bacterial deposits (2) They form a unique ectodermal interruption. A special seal of epithelium (**junctional epithelium**) and connective tissue is present between the external environment and the internal parts of the body. - The accumulation and metabolism of bacteria on these hard surfaces are considered the **primary causes of caries, gingivitis, periodontitis, peri-implantitis, and, sometimes, bad breath.** - In periodontitis patients, periodontal pockets form, creating a subgingival niche that increases the root surface area for microbial colonization, **resulting in a subgingival microbial biofilm.**  From a microbiological viewpoint, **teeth and implants** are unique for **two reasons**: (1) They provide a hard, **non-shedding** surface that allows for the development of extensive structured bacterial deposits (2) They form a unique ectodermal interruption. A special seal of epithelium (**junctional epithelium**) and connective tissue is present between the external environment and the internal parts of the body. - The accumulation and metabolism of bacteria on these hard surfaces are considered the **primary causes of caries, gingivitis, periodontitis, peri-implantitis, and, sometimes, bad breath.** - In periodontitis patients, periodontal pockets form, creating a subgingival niche that increases the root surface area for microbial colonization, **resulting in a subgingival microbial biofilm.** Labelled anatomical diagram of a tooth and gingiva. The illustration shows the vertical section of gum tissue attaching to a tooth root. Labels point to specific structures: 'Gingival sulcus' at the top, 'Sulcular epithelium (B)' lining the sulcus, 'Base of gingival sulcus', 'Junctional epithelium (C)' forming the attachment along the root surface, 'Oral epithelium (A)' on the outer gum surface, 'Connective tissue' within the gum, and 'Gingival fibers' anchoring the tissue. **Fig. 10.2** Subgingival plaque. (A) Diagram depicting the plaque–bacteria association between the tooth surface and the periodontal tissues. (B) Scanning electron photomicrograph of a cross-section of cementum (C) with attached subgingival plaque (AP). The area shown is within a periodontal pocket. (C) Scanning electron micrograph of cocci and filaments associated with the surface of pocket epithelium in a case of marginal gingivitis. x3000. (D) Left, Diagrammatic representation of the histologic structure of subgingival plaque. Right, Histologic section of subgingival plaque. Arrow with box, **Sulcular epithelium**. White arrow, Predominantly gram-negative unattached zone. Black arrow, Tooth surface. Asterisk, Predominantly gram-positive attached zone. (B, Courtesy Dr. J. Sottosanti, La Jolla, California.)     **Fig. 10.2** Subgingival plaque. (A) Diagram depicting the plaque–bacteria association between the tooth surface and the periodontal tissues. (B) Scanning electron photomicrograph of a cross-section of cementum (C) with attached subgingival plaque (AP). The area shown is within a periodontal pocket. (C) Scanning electron micrograph of cocci and filaments associated with the surface of pocket epithelium in a case of marginal gingivitis. x3000. (D) Left, Diagrammatic representation of the histologic structure of subgingival plaque. Right, Histologic section of subgingival plaque. Arrow with box, **Sulcular epithelium**. White arrow, Predominantly gram-negative unattached zone. Black arrow, Tooth surface. Asterisk, Predominantly gram-positive attached zone. (B, Courtesy Dr. J. Sottosanti, La Jolla, California.) Labelled diagram illustrating subgingival plaque distribution. Labels include 'Tooth-attached plaque', 'Unattached plaque', 'Epithelial-associated plaque', 'Bacteria within connective tissue', and 'Bacteria on bone surface'. Shows anatomical structures like tooth surface and periodontal pocket. Scanning electron photomicrograph showing cross-section of cementum labeled 'C' with attached subgingival plaque labeled 'AP'. Darker regions represent cementum structure, while lighter fibrous areas indicate plaque formation within a periodontal pocket. High-magnification scanning electron micrograph at 3000x magnification showing bacterial colonies (cocci and filaments) adhering to the surface of pocket epithelium in a case of marginal gingivitis. Composite figure showing: Left panel - Diagrammatic representation of subgingival plaque histology with labels for sulcular epithelium, unattached zone, tooth surface, and attached zone; Right panel - Corresponding histologic section image with arrows pointing to specific zones and an asterisk marking the predominantly gram-positive attached zone. <em>• Bacterial species identified in all sites investigated by Aas and coworkers belonged to the genera Gemella, Granulicatella, Streptococcus, and Veillonella.</em> <em>• The most commonly found species in all subjects and all intra-oral sites investigated was S. mitis, which is considered a <b>pioneer species</b>, or <b>primary colonizer</b>.</em> <em>• <b>Streptococci</b> are thought to be universally present in all sites within the mouth, but the distribution is thought to vary in different ecological niches of the oral cavity.</em> <em>• It has been suggested that teeth are the primary habitat for periodontal pathogens because soon after a <b>full-mouth tooth extraction</b> in patients with severe periodontitis, key pathogens such as <b>Aggregatibacter actinomycetemcomitans</b> and <b>P. gingivalis</b> <b>disappeared</b> from the oral cavity, as determined by bacterial culturing techniques.</em> <em>• <b>Prevotella intermedia</b> and other <b>black-pigmented Prevotella spp.</b> <b>remained</b>, but at lower detection frequencies and numbers.</em> <em>• Bacterial species identified in all sites investigated by Aas and coworkers belonged to the genera Gemella, Granulicatella, Streptococcus, and Veillonella.</em> <em>• The most commonly found species in all subjects and all intra-oral sites investigated was S. mitis, which is considered a <b>pioneer species</b>, or <b>primary colonizer</b>.</em> <em>• <b>Streptococci</b> are thought to be universally present in all sites within the mouth, but the distribution is thought to vary in different ecological niches of the oral cavity.</em> <em>• It has been suggested that teeth are the primary habitat for periodontal pathogens because soon after a <b>full-mouth tooth extraction</b> in patients with severe periodontitis, key pathogens such as <b>Aggregatibacter actinomycetemcomitans</b> and <b>P. gingivalis</b> <b>disappeared</b> from the oral cavity, as determined by bacterial culturing techniques.</em> <em>• <b>Prevotella intermedia</b> and other <b>black-pigmented Prevotella spp.</b> <b>remained</b>, but at lower detection frequencies and numbers.</em> The University of Western Australia logo located in the top-left corner. The development and composition of the oral microbiome The mother is the **main source** of the oral microbiome in the newborn baby. The microbial composition of dental biofilms varies at distinct sites on a tooth (**fissures**, **approximal surfaces**, **gingival crevice**) due to inherent differences in their anatomy and biology (Papaioannou et al . 2009; Marsh et al . 2016b) *Fissures* are influenced by saliva and the diet and support a relatively sparse microbiota consisting of mainly saccharolytic Gram- positive bacteria, such as streptococci, while obligately anaerobic, and especially Gram- negative species, are rarely recovered. | | | | :--- | :--- | | **Dental X-ray showing a tooth from 3 views with descriptions of bacterial composition and environments at the fissure, approximal, and gingival crevice locations.** | |  The development and composition of the oral microbiome The mother is the **main source** of the oral microbiome in the newborn baby. The microbial composition of dental biofilms varies at distinct sites on a tooth (**fissures**, **approximal surfaces**, **gingival crevice**) due to inherent differences in their anatomy and biology (Papaioannou et al . 2009; Marsh et al . 2016b) *Fissures* are influenced by saliva and the diet and support a relatively sparse microbiota consisting of mainly saccharolytic Gram- positive bacteria, such as streptococci, while obligately anaerobic, and especially Gram- negative species, are rarely recovered. | | | | :--- | :--- | | **Dental X-ray showing a tooth from 3 views with descriptions of bacterial composition and environments at the fissure, approximal, and gingival crevice locations.** | | A labeled diagram of a tooth illustrating bacterial composition and environmental conditions at three distinct anatomical sites: Fissure (top), Approximal (left), and Gingival Crevice (right). The central image shows the tooth with labels 'S' for Smooth surface and 'B' for Bitewing view. Red arrows point from the central tooth to corresponding text boxes detailing specific bacterial species (e.g., Streptococcus, Actinomyces, Eubacterium) and physiological factors (e.g., pH levels, oxygen tolerance) for each location. **Dental Biofilms** * Microbial populations on the surfaces of teeth are excellent examples of biofilm communities. * The architecture of a dental biofilm has many features in common with other biofilms. * It is **heterogeneous in structure**, with clear evidence of open fluid- filled channels running through the biofilm mass. * **Nutrients reach the sessile (attached) microcolonies by diffusion through water channels to microbial microcolonies.**  **Dental Biofilms** * Microbial populations on the surfaces of teeth are excellent examples of biofilm communities. * The architecture of a dental biofilm has many features in common with other biofilms. * It is **heterogeneous in structure**, with clear evidence of open fluid- filled channels running through the biofilm mass. * **Nutrients reach the sessile (attached) microcolonies by diffusion through water channels to microbial microcolonies.** Labelled diagram: An artistic rendering illustrating the heterogeneous structure of a dental biofilm. The image depicts rod-shaped (orange) and spherical (blue) microbial cells embedded in a matrix of extracellular polymeric substances. Visible are open fluid-filled channels running through the biofilm mass, which facilitates nutrient diffusion to sessile microcolonies. - The process of dental biofilm formation can be divided into several phases: (1) The **formation of the pellicle** on the tooth surface (2) The initial adhesion/attachment of bacteria (3) Colonization/biofilm maturation - The development of dental biofilms follows a well-established sequence of events where initial colonizers, predominantly streptococci, act as a foundation to establish an environment suitable for **later colonization by potentially more pathogenic species** - Initially, **bacteria can be held reversibly near to the surface by weak**, long- range, physicochemical forces between the electrical charge on the molecules on the pellicle- coated surface and those on the microbial cell. - The process of dental biofilm formation can be divided into several phases: (1) The **formation of the pellicle** on the tooth surface (2) The initial adhesion/attachment of bacteria (3) Colonization/biofilm maturation - The development of dental biofilms follows a well-established sequence of events where initial colonizers, predominantly streptococci, act as a foundation to establish an environment suitable for **later colonization by potentially more pathogenic species** - Initially, **bacteria can be held reversibly near to the surface by weak**, long- range, physicochemical forces between the electrical charge on the molecules on the pellicle- coated surface and those on the microbial cell. University of Western Australia logo located in the top-left corner. (1) The formation of the pellicle on the tooth surface - All surfaces in the oral cavity, including hard and soft tissues, are coated with a layer of organic material known as the **acquired pellicle**. - **Microorganisms rarely colonize clean enamel.** - Within seconds of eruption, or following cleaning, tooth surfaces become coated with a conditioning film (**acquired pellicle**) of molecules (biologically active proteins, phosphoproteins, and glycoproteins) **derived mainly from saliva (but also from GCF and bacteria)** (Hannig et al . 2005). - **The pellicle on tooth surfaces** consists of more than 180 **peptides, proteins, and glycoproteins**, including keratins, mucins, proline-rich proteins, and other molecules that can function as **adhesion sites (receptors)** for bacteria. (1) The formation of the pellicle on the tooth surface - All surfaces in the oral cavity, including hard and soft tissues, are coated with a layer of organic material known as the **acquired pellicle**. - **Microorganisms rarely colonize clean enamel.** - Within seconds of eruption, or following cleaning, tooth surfaces become coated with a conditioning film (**acquired pellicle**) of molecules (biologically active proteins, phosphoproteins, and glycoproteins) **derived mainly from saliva (but also from GCF and bacteria)** (Hannig et al . 2005). - **The pellicle on tooth surfaces** consists of more than 180 **peptides, proteins, and glycoproteins**, including keratins, mucins, proline-rich proteins, and other molecules that can function as **adhesion sites (receptors)** for bacteria. The University of Western Australia logo located in the top-left corner. # 2-Initial Adhesion/Attachment of Bacteria The University of Western Australia logo is present in the top-left corner. * The interactions between microbial cell surface "**adhesin**" molecules and salivary pellicle receptors determine if a bacterial cell will stay on the surface. * Only a relatively small proportion of oral bacteria possess adhesins that interact with receptors in the host pellicle. These species are considered the "**primary colonizers**" of tooth surfaces. The primary colonizers provide new binding sites for adhesion by other oral bacteria. * Initial colonizers such as streptococci produce **lactic acid** which can be utilized as a carbon and energy source by Veillonella species. * **Veillonella spp.** are amongst the most prevalent bacterial species in dental biofilms and are thought to have a similar role to oral fusobacteria (such as **Fusobacterium nucleatum** in that they are able to act as **bridging organisms** that are able to support the colonization and growth of later colonizers, **by their ability to bind to both early and late colonizers** Colonization of teeth by bacteria occur in three phases * **Phase 1** is transport to the tooth surface—Brownian motion (average displacement, 40 μm/hour) * **Phase 2** is initial reversible adhesion—Van der Waals attractive forces and electrostatic repulsive forces * **Phase 3** is strong attachment - Proteins, Glycoproteins, or polysaccharides 2-Initial Adhesion/Attachment of Bacteria The University of Western Australia logo is present in the top-left corner. * The interactions between microbial cell surface "**adhesin**" molecules and salivary pellicle receptors determine if a bacterial cell will stay on the surface. * Only a relatively small proportion of oral bacteria possess adhesins that interact with receptors in the host pellicle. These species are considered the "**primary colonizers**" of tooth surfaces. The primary colonizers provide new binding sites for adhesion by other oral bacteria. * Initial colonizers such as streptococci produce **lactic acid** which can be utilized as a carbon and energy source by Veillonella species. * **Veillonella spp.** are amongst the most prevalent bacterial species in dental biofilms and are thought to have a similar role to oral fusobacteria (such as **Fusobacterium nucleatum** in that they are able to act as **bridging organisms** that are able to support the colonization and growth of later colonizers, **by their ability to bind to both early and late colonizers** Colonization of teeth by bacteria occur in three phases * **Phase 1** is transport to the tooth surface—Brownian motion (average displacement, 40 μm/hour) * **Phase 2** is initial reversible adhesion—Van der Waals attractive forces and electrostatic repulsive forces * **Phase 3** is strong attachment - Proteins, Glycoproteins, or polysaccharides The University of Western Australia logo located in the top-left corner of the slide. <!--Table 10.1 - Overview of Primary and Secondary Colonizers in Dental Plaque --> <table> <tr> <td><strong>Primary colonizers</strong></td> <td> Streptococcus gordonii<br> Streptococcus intermedius<br> Streptococcus mitis<br> Streptococcus oralis<br> Streptococcus sanguinis<br> Actinomyces gerencseriae<br> Actinomyces israelii<br> Actinomyces naeslundii<br> Actinomyces oris<br> Aggregatibacter actinomycetemcomitans serotype a<br> Capnocytophaga gingivalis<br> Capnocytophaga ochracea<br> Capnocytophaga sputigena<br> Eikenella corrodens<br> Actinomyces odontolyticus<br> Veillonella parvula </td> </tr> <tr> <td><strong>Secondary colonizers</strong></td> <td> Campylobacter gracilis<br> Campylobacter rectus<br> Campylobacter showae<br> Eubacterium nodatum<br> Aggregatibacter actinomycetemcomitans serotype b<br> Fusobacterium nucleatum spp. nucleatum<br> Fusobacterium nucleatum spp. vincentii<br> Fusobacterium nucleatum spp. polymorphum<br> Fusobacterium periodonticum<br> Parvimonas micra<br> Prevotella intermedia<br> Prevotella loescheii<br> Prevotella nigrescens<br> Streptococcus constellatus<br> Tannerella forsythia<br> Porphyromonas gingivalis<br> Treponema denticola </td> </tr> </table> * The primary colonizing bacteria adhered to the tooth surface provide new receptors for attachment by other bacteria, in a process known as "**coadhesion**" or "**coaggregation**". * The transition from early supragingival dental biofilm to more mature biofilm developing beneath the gingival margin involves a shift in the microbial population from primarily **gram-positive** organisms to high numbers of **gram-negative** bacteria. * A key organism in dental biofilm development is <strong>Fusobacterium nucleatum</strong>. This species can co-adhere to most oral bacteria and acts as an <strong>important bridging organism between early and later colonizing species</strong>.  <!--Table 10.1 - Overview of Primary and Secondary Colonizers in Dental Plaque --> <table> <tr> <td><strong>Primary colonizers</strong></td> <td> Streptococcus gordonii<br> Streptococcus intermedius<br> Streptococcus mitis<br> Streptococcus oralis<br> Streptococcus sanguinis<br> Actinomyces gerencseriae<br> Actinomyces israelii<br> Actinomyces naeslundii<br> Actinomyces oris<br> Aggregatibacter actinomycetemcomitans serotype a<br> Capnocytophaga gingivalis<br> Capnocytophaga ochracea<br> Capnocytophaga sputigena<br> Eikenella corrodens<br> Actinomyces odontolyticus<br> Veillonella parvula </td> </tr> <tr> <td><strong>Secondary colonizers</strong></td> <td> Campylobacter gracilis<br> Campylobacter rectus<br> Campylobacter showae<br> Eubacterium nodatum<br> Aggregatibacter actinomycetemcomitans serotype b<br> Fusobacterium nucleatum spp. nucleatum<br> Fusobacterium nucleatum spp. vincentii<br> Fusobacterium nucleatum spp. polymorphum<br> Fusobacterium periodonticum<br> Parvimonas micra<br> Prevotella intermedia<br> Prevotella loescheii<br> Prevotella nigrescens<br> Streptococcus constellatus<br> Tannerella forsythia<br> Porphyromonas gingivalis<br> Treponema denticola </td> </tr> </table> * The primary colonizing bacteria adhered to the tooth surface provide new receptors for attachment by other bacteria, in a process known as "**coadhesion**" or "**coaggregation**". * The transition from early supragingival dental biofilm to more mature biofilm developing beneath the gingival margin involves a shift in the microbial population from primarily **gram-positive** organisms to high numbers of **gram-negative** bacteria. * A key organism in dental biofilm development is <strong>Fusobacterium nucleatum</strong>. This species can co-adhere to most oral bacteria and acts as an <strong>important bridging organism between early and later colonizing species</strong>. Table titled 'Overview of Primary and Secondary Colonizers in Dental Plaque'. The table is divided into two main sections: 'Primary colonizers' and 'Secondary colonizers', each listing specific bacterial species relevant to dental plaque formation.   Scientific diagram illustrating the initial stages of biofilm formation on a tooth surface. The purple bar at the bottom is labeled 'ENAMEL'. Above it are small geometric shapes (triangles and circles) representing pellicle formation. A blue oval bacterium is shown approaching via a red arrow labeled '2i Transport-passive', followed by another red arrow indicating '2ii Reversible attachment' to a yellow circular bacterium already attached to the enamel. Text annotations include 'Weak, long range, van der Waals forces'. Scientific diagram illustrating adhesion mechanisms. On the left, under label '3 Adhesin-receptor', two yellow bacteria are shown with specific receptors binding irreversibly to the pellicle/enamel interface. On the right, under label '4 Co-adhesion', a larger blue oval bacterium ('2° colonizer') is shown attaching to two smaller yellow bacteria ('1° colonizer'), which are themselves attached to the enamel. Arrows indicate short-range interactions. **Fig. 10.10 Diagrammatic representation of initial plaque formation. Early colonizers bind to receptors in the pellicle. Each adherent cell becomes in turn the nascent surface and bridge for additional species (secondary colonizers). The complementary sets of adhesin receptor symbols (example in box) represent the various kinds of coaggregations as well as the interactions with molecules in the pellicle. The symbol with a stem (adhesin) represents a cellular component that is heat-inactivated (cell suspension heated to 85°C for 30 minutes) and sensitive to protease treatment. The cell type that exhibits the complementary symbol (receptor) is insensitive to either treatment. The symbols with a rectangular shape represent lactose-inhibitable coaggregations; the others are lactose noninhibitable.** A. actinomycetemcomitans, Aggregatibacter actinomycetemcomitans; A. israelii, Actinomyces israelii; A. naeslundii, Actinomyces naeslundii; C. gingivalis, Capnocytophaga gingivalis; C. ochracea, Capnocytophaga ochracea; C. sputigena, Capnocytophaga sputigena; F. nucleatum, Fusobacterium nucleatum; H. parainfluenzae, Haemophilus parainfluenzae; P. acnes, Propionibacterium acnes; P. denticola, Prevotella denticola; P. gingivalis, Porphyromonas gingivalis; P. loescheii, Prevotella loescheii; S. flueggei, Selenomonas flueggei; S. gordonii, Streptococcus gordonii; S. mitis, Streptococcus mitis; S. oralis, Streptococcus oralis; S. sanguis, Streptococcus sanguis; V. atypica, Veillonella atypica. (Adapted from Kolenbrander PE, London J. Adhere today, here tomorrow: oral bacterial adherence. J Bacteriol. 1993;175:3247.)  **Fig. 10.10 Diagrammatic representation of initial plaque formation. Early colonizers bind to receptors in the pellicle. Each adherent cell becomes in turn the nascent surface and bridge for additional species (secondary colonizers). The complementary sets of adhesin receptor symbols (example in box) represent the various kinds of coaggregations as well as the interactions with molecules in the pellicle. The symbol with a stem (adhesin) represents a cellular component that is heat-inactivated (cell suspension heated to 85°C for 30 minutes) and sensitive to protease treatment. The cell type that exhibits the complementary symbol (receptor) is insensitive to either treatment. The symbols with a rectangular shape represent lactose-inhibitable coaggregations; the others are lactose noninhibitable.** A. actinomycetemcomitans, Aggregatibacter actinomycetemcomitans; A. israelii, Actinomyces israelii; A. naeslundii, Actinomyces naeslundii; C. gingivalis, Capnocytophaga gingivalis; C. ochracea, Capnocytophaga ochracea; C. sputigena, Capnocytophaga sputigena; F. nucleatum, Fusobacterium nucleatum; H. parainfluenzae, Haemophilus parainfluenzae; P. acnes, Propionibacterium acnes; P. denticola, Prevotella denticola; P. gingivalis, Porphyromonas gingivalis; P. loescheii, Prevotella loescheii; S. flueggei, Selenomonas flueggei; S. gordonii, Streptococcus gordonii; S. mitis, Streptococcus mitis; S. oralis, Streptococcus oralis; S. sanguis, Streptococcus sanguis; V. atypica, Veillonella atypica. (Adapted from Kolenbrander PE, London J. Adhere today, here tomorrow: oral bacterial adherence. J Bacteriol. 1993;175:3247.) Diagram illustrating the sequential stages of dental plaque formation. The diagram is vertically stratified into three zones: 'Acquired pellicle' at the bottom, 'Early colonizers' in the middle, and 'Late colonizers' at the top. It visually maps the specific bacterial species involved in each stage, their adhesion mechanisms via adhesins and receptors, and the resulting biofilm structure. Communication Between Biofilm Bacteria • Bacterial cells do not exist in isolation. In a biofilm, capacity to communicate with each other. • One example of this is **“quorum sensing”**, in which signaling molecule that accumulates in the local environment triggers a response such as a change in the expression genes once they reach a critical threshold concentration. There are 2 types of signaling molecules of plaque bacteria: • **Peptides** released by gram-positive organisms during pump... • In Streptococcus mutans , quorum sensing is mediated by competence stimulating peptide (CSP) (Li et al . 2017). • “Universal” signal molecule autoinducer 2 (AI-2).  Communication Between Biofilm Bacteria • Bacterial cells do not exist in isolation. In a biofilm, capacity to communicate with each other. • One example of this is **“quorum sensing”**, in which signaling molecule that accumulates in the local environment triggers a response such as a change in the expression genes once they reach a critical threshold concentration. There are 2 types of signaling molecules of plaque bacteria: • **Peptides** released by gram-positive organisms during pump... • In Streptococcus mutans , quorum sensing is mediated by competence stimulating peptide (CSP) (Li et al . 2017). • “Universal” signal molecule autoinducer 2 (AI-2). Microscopic image showing green bacterial cells forming a biofilm. **Fig. 10.11** Long-standing supragingival plaque near the gingival margin demonstrating a "corn cob" arrangement. A central gram-negative filamentous core supports the outer coccal cells, which are firmly attached by inter-bacterial adherence or coaggregation.  **Fig. 10.11** Long-standing supragingival plaque near the gingival margin demonstrating a "corn cob" arrangement. A central gram-negative filamentous core supports the outer coccal cells, which are firmly attached by inter-bacterial adherence or coaggregation. Scanning electron micrograph (SEM) showing bacterial plaque structure. | |\input| | --- |\input| | Dates |\input| | Hypothesis |\input| | Main assumption |\input| | 19th century |\input| | Golden age of microbiology |\input| | Specific pathogens are associated with systemic conditions (no oral pathogens found) ||\input| | Early to mid-20th century |\input| | Non-specific plaque hypothesis |\input| | Periodontal disease is not caused by specific oral pathogens ||\input| | 1976 |\input| | Specific plaque hypothesis |\input| | SEM technology may permit the identification of specific oral pathogens ||\input| | 1986 |\input| | (back to) Non-specific plaque hypothesis |\input| | Overall activity of microbes could lead to disease through differences in virulence ||\input| | 1994 |\input| | Ecological plaque hypothesis |\input| | Disease results from a microbial imbalance caused by ecological stress ||\input| | 2012 |\input| | Keystone pathogen hypothesis |\input| | Certain low-abundance microbial pathogens cause inflammation by interfering with host immune response ||\input| | 2019 |\input| | IMPEDE Model (Inflammation-Mediated-Polymicrobial-Emergence and Dysbiotic-Exacerbation") | |\input| | Inflammation is the driver of the ultimate dysbiosis that leads to periodontitis rather than the pathogenic microbes themselves ||\input| --- **Scientific editor, Canadian Journal of Dental Hygiene** Correspondence: Dr Salme E Lavigne; scientificeditor@cdha.ca ©2023 Canadian Dental Hygienists Association Can J Dent Hyg 2023;57(2): 75–77 | 75  | |\input| | --- |\input| | Dates |\input| | Hypothesis |\input| | Main assumption |\input| | 19th century |\input| | Golden age of microbiology |\input| | Specific pathogens are associated with systemic conditions (no oral pathogens found) ||\input| | Early to mid-20th century |\input| | Non-specific plaque hypothesis |\input| | Periodontal disease is not caused by specific oral pathogens ||\input| | 1976 |\input| | Specific plaque hypothesis |\input| | SEM technology may permit the identification of specific oral pathogens ||\input| | 1986 |\input| | (back to) Non-specific plaque hypothesis |\input| | Overall activity of microbes could lead to disease through differences in virulence ||\input| | 1994 |\input| | Ecological plaque hypothesis |\input| | Disease results from a microbial imbalance caused by ecological stress ||\input| | 2012 |\input| | Keystone pathogen hypothesis |\input| | Certain low-abundance microbial pathogens cause inflammation by interfering with host immune response ||\input| | 2019 |\input| | IMPEDE Model (Inflammation-Mediated-Polymicrobial-Emergence and Dysbiotic-Exacerbation") | |\input| | Inflammation is the driver of the ultimate dysbiosis that leads to periodontitis rather than the pathogenic microbes themselves ||\input| --- **Scientific editor, Canadian Journal of Dental Hygiene** Correspondence: Dr Salme E Lavigne; scientificeditor@cdha.ca ©2023 Canadian Dental Hygienists Association Can J Dent Hyg 2023;57(2): 75–77 | 75 A structured table summarizing the historical evolution of periodontal plaque hypotheses. It contains three columns: 'Dates', 'Hypothesis', and 'Main assumption'. The rows chronologically list theories from the 19th century through 2019, including the Golden age of microbiology, Non-specific plaque hypothesis (early-mid 20th c), Specific plaque hypothesis (1976), a return to Non-specific hypothesis (1986), Ecological plaque hypothesis (1994), Keystone pathogen hypothesis (2012), and the IMPEDE Model (2019). Each row details the specific main assumption associated with that era or theory. <table><tr><td>Plaque reduction</td><td>Reduced inflammation</td><td>Low GCF flow</td><td>Predominantly</td></tr><tr><td></td><td></td><td>higher E<sub>h</sub></td><td>gram-positive</td></tr><tr><td>Plaque accumulation</td><td></td><td></td><td>micobiota,</td></tr><tr><td></td><td></td><td></td><td>many facultative</td></tr><tr><td></td><td>Increased inflammation</td><td></td><td>anaerobes,</td></tr><tr><td></td><td></td><td>Environmental change</td><td>gingival health</td></tr><tr><td></td><td></td><td>High GCF flow</td><td>Ecological shift</td></tr><tr><td></td><td></td><td>lower E<sub>h</sub></td><td></td></tr><tr><td></td><td></td><td></td><td>Predominantly</td></tr><tr><td></td><td></td><td></td><td>gram-negative</td></tr><tr><td></td><td></td><td></td><td>micobiota,</td></tr><tr><td></td><td></td><td></td><td>many obligate</td></tr><tr><td></td><td></td><td></td><td>anaerobes,</td></tr><tr><td></td><td></td><td></td><td>periodontal disease</td></tr></table> **Fig. 10.25** Ecologic plaque hypothesis in relation to periodontal diseases: gingivitis and periodontitis. The accumulation of plaque causes the inflammation of adjacent tissues (gingivitis) and other environmental changes that favor the growth of gram-negative anaerobes and proteolytic species, including periodontal pathogens. The increased proportions of such species result in the destruction of periodontal tissues (i.e., periodontitis). *E<sub>h</sub>, Redox potential; GCF, gingival crevicular fluid.* (Adapted from Marsh PD. Microbial ecology of dental plaque and its significance in health and disease. *Adv Dent Res.* 1994;8:263.)  <table><tr><td>Plaque reduction</td><td>Reduced inflammation</td><td>Low GCF flow</td><td>Predominantly</td></tr><tr><td></td><td></td><td>higher E<sub>h</sub></td><td>gram-positive</td></tr><tr><td>Plaque accumulation</td><td></td><td></td><td>micobiota,</td></tr><tr><td></td><td></td><td></td><td>many facultative</td></tr><tr><td></td><td>Increased inflammation</td><td></td><td>anaerobes,</td></tr><tr><td></td><td></td><td>Environmental change</td><td>gingival health</td></tr><tr><td></td><td></td><td>High GCF flow</td><td>Ecological shift</td></tr><tr><td></td><td></td><td>lower E<sub>h</sub></td><td></td></tr><tr><td></td><td></td><td></td><td>Predominantly</td></tr><tr><td></td><td></td><td></td><td>gram-negative</td></tr><tr><td></td><td></td><td></td><td>micobiota,</td></tr><tr><td></td><td></td><td></td><td>many obligate</td></tr><tr><td></td><td></td><td></td><td>anaerobes,</td></tr><tr><td></td><td></td><td></td><td>periodontal disease</td></tr></table> **Fig. 10.25** Ecologic plaque hypothesis in relation to periodontal diseases: gingivitis and periodontitis. The accumulation of plaque causes the inflammation of adjacent tissues (gingivitis) and other environmental changes that favor the growth of gram-negative anaerobes and proteolytic species, including periodontal pathogens. The increased proportions of such species result in the destruction of periodontal tissues (i.e., periodontitis). *E<sub>h</sub>, Redox potential; GCF, gingival crevicular fluid.* (Adapted from Marsh PD. Microbial ecology of dental plaque and its significance in health and disease. *Adv Dent Res.* 1994;8:263.) Labelled diagram illustrating the ecologic plaque hypothesis. The visual structure shows a progression from left to right involving three main stages separated by double-headed arrows indicating feedback loops or bidirectional relationships. Stage 1 includes 'Plaque reduction' leading to 'Reduced inflammation' versus 'Plaque accumulation' leading to 'Increased inflammation'. Stage 2 shows 'Low GCF flow higher Eh' versus 'High GCF flow lower Eh'. Stage 3 depicts 'Predominantly gram-positive micobiota...' associated with 'gingival health' versus 'Predominantly gram-negative micobiota...' associated with 'periodontal disease'. A central label 'Environmental change' and 'Ecological shift' are positioned between the stages. Arrows connect all elements to show causal relationships. The University of Western Australia Acquired enamel pellicle Tooth Gingiva 0–18 h Pioneer colonizers 18 h–4 d Biofilm maturation > 4 d Microbial dysbiosis Subgingival dental biofilm Healthy tooth Periodontal disease Fig. 10.7 Accumulation of dental biofilm and progression to disease. Good oral hygiene maintains low levels of dental biofilm at the gum margin. The acquired enamel pellicle, a layer of protein and glycoprotein largely derived from saliva, is not removed during tooth cleaning and forms attachment sites for pioneer colonizing bacteria. Initial attachment starts within minutes. Without further oral hygiene, the dental biofilm thickens and an extracellular matrix accumulates (“biofilm maturation”) after around 18 h. This mature biofilm reorganizes over the next few days, without dramatically increasing in thickness. Interactions between the biofilm and gingival tissue triggers inflammation, indicated by reddening of the gingiva. Ultimately, this can lead to microbial dysbiosis and the accumulation of significant biofilm below the gingival margin which leads to chronic inflammation and loss of tissue surrounding the tooth. Ultimately, the biofilm-laden tooth becomes mobile and requires extraction. A tooth extracted for periodontal disease is shown.    The University of Western Australia Acquired enamel pellicle Tooth Gingiva 0–18 h Pioneer colonizers 18 h–4 d Biofilm maturation > 4 d Microbial dysbiosis Subgingival dental biofilm Healthy tooth Periodontal disease Fig. 10.7 Accumulation of dental biofilm and progression to disease. Good oral hygiene maintains low levels of dental biofilm at the gum margin. The acquired enamel pellicle, a layer of protein and glycoprotein largely derived from saliva, is not removed during tooth cleaning and forms attachment sites for pioneer colonizing bacteria. Initial attachment starts within minutes. Without further oral hygiene, the dental biofilm thickens and an extracellular matrix accumulates (“biofilm maturation”) after around 18 h. This mature biofilm reorganizes over the next few days, without dramatically increasing in thickness. Interactions between the biofilm and gingival tissue triggers inflammation, indicated by reddening of the gingiva. Ultimately, this can lead to microbial dysbiosis and the accumulation of significant biofilm below the gingival margin which leads to chronic inflammation and loss of tissue surrounding the tooth. Ultimately, the biofilm-laden tooth becomes mobile and requires extraction. A tooth extracted for periodontal disease is shown. A labeled diagram illustrating the four stages of dental biofilm accumulation and periodontal disease progression: 'Acquired enamel pellicle' (Tooth/Gingiva), 'Pioneer colonizers' (0-18 h), 'Biofilm maturation' (18 h-4 d), and 'Microbial dysbiosis' (> 4 d). The sequence shows bacterial colonization on the tooth surface over time. An anatomical illustration showing a cross-section of a healthy tooth with intact gingival tissue surrounding it. A clinical photograph of an extracted tooth exhibiting severe periodontal disease, showing significant tissue loss and inflammation at the gum margin. **Bold Text:** **Fig. 10.24** **Main Caption and Body Text:** Associations among subgingival species. The data were derived from 13,261 subgingival plaque samples taken from the mesial aspect of each tooth in 185 adult subjects. Each sample was individually analyzed for the presence of 40 subgingival species with the use of checkerboard DNA-DNA hybridization. Associations were sought among species via cluster analysis and community ordination techniques. The complexes to the left consist of species that are thought to colonize the tooth surface and to proliferate at an early stage. The orange complex becomes numerically dominant later; it is thought to bridge the early colonizers and the red complex species, which become numerically more dominant during the later stages of plaque development. A. actinomyces comitans, Aggregatibacter actinomycetemcomitans; A. odontolytica, Actinomyces odontolytica; C. concisus, Campylobacter concisus; C. gingivalis, Capnocytophaga gingivalis; C. gracilis, Campylobacter gracilis; C. ochracea, Capnocytophaga ochracea; C. rectus, Campylobacter rectus; C. showae, Campylobacter showae; C. sputigena, Capnocytophaga sputigena; E. corrodens, Eikenella corrodens; F. nuc., Fusobacterium nucleatum; F. periodonticum, Fusobacterium periodonticum; P. gingivalis, Porphyromonas gingivalis; P. micra, Parvimonas micra; P. nigrescens, Prevotella nigrescens; S. constellatus, Streptococcus constellatus; S. mitis, Streptococcus mitis; S. noxia, Selenomonas noxia; S. oralis, Streptococcus oralis; S. sanguis, Streptococcus sanguis; T. denticola, Treponema denticola; T. forsythia, Tannerella forsythia; V. parvula, Veillonella parvula. (Adapted from Socransky SS, Haffajee AD, Cugini MA, et al. Microbial complexes in subgingival plaque. J Clin Periodontol. 1998;25:134.) **Figure Content (Bulleted List of Species Groups):** * **Blue Oval (Top Left):** * Actinomyces species * **Purple Oval (Top Right):** * V. parvula * A. odontolyticus * **Yellow Oval (Left):** * S. mitis * S. oralis * S. sanguis * Streptococcus sp. * S. gordonii * S. intermedius * **Large Orange Oval (Center):** * C. gracilis * C. rectus * S. constellatus * E. nodatum * P. intermedia * P. nigrescens * P. micros * F. nuc. vincentii * F. nuc. nucleatum * F. nuc. polymorphum * F. periodonticum * C. showae * A. actino. b * S. noxia * **Small Green Oval (Bottom Left):** * E. corrodens * C. gingivalis * C. sputigena * C. ochracea * C. concisus * A. actino. a * **Red Oval (Far Right):** * P. gingivalis * T. forsythia * T. denticola  **Bold Text:** **Fig. 10.24** **Main Caption and Body Text:** Associations among subgingival species. The data were derived from 13,261 subgingival plaque samples taken from the mesial aspect of each tooth in 185 adult subjects. Each sample was individually analyzed for the presence of 40 subgingival species with the use of checkerboard DNA-DNA hybridization. Associations were sought among species via cluster analysis and community ordination techniques. The complexes to the left consist of species that are thought to colonize the tooth surface and to proliferate at an early stage. The orange complex becomes numerically dominant later; it is thought to bridge the early colonizers and the red complex species, which become numerically more dominant during the later stages of plaque development. A. actinomyces comitans, Aggregatibacter actinomycetemcomitans; A. odontolytica, Actinomyces odontolytica; C. concisus, Campylobacter concisus; C. gingivalis, Capnocytophaga gingivalis; C. gracilis, Campylobacter gracilis; C. ochracea, Capnocytophaga ochracea; C. rectus, Campylobacter rectus; C. showae, Campylobacter showae; C. sputigena, Capnocytophaga sputigena; E. corrodens, Eikenella corrodens; F. nuc., Fusobacterium nucleatum; F. periodonticum, Fusobacterium periodonticum; P. gingivalis, Porphyromonas gingivalis; P. micra, Parvimonas micra; P. nigrescens, Prevotella nigrescens; S. constellatus, Streptococcus constellatus; S. mitis, Streptococcus mitis; S. noxia, Selenomonas noxia; S. oralis, Streptococcus oralis; S. sanguis, Streptococcus sanguis; T. denticola, Treponema denticola; T. forsythia, Tannerella forsythia; V. parvula, Veillonella parvula. (Adapted from Socransky SS, Haffajee AD, Cugini MA, et al. Microbial complexes in subgingival plaque. J Clin Periodontol. 1998;25:134.) **Figure Content (Bulleted List of Species Groups):** * **Blue Oval (Top Left):** * Actinomyces species * **Purple Oval (Top Right):** * V. parvula * A. odontolyticus * **Yellow Oval (Left):** * S. mitis * S. oralis * S. sanguis * Streptococcus sp. * S. gordonii * S. intermedius * **Large Orange Oval (Center):** * C. gracilis * C. rectus * S. constellatus * E. nodatum * P. intermedia * P. nigrescens * P. micros * F. nuc. vincentii * F. nuc. nucleatum * F. nuc. polymorphum * F. periodonticum * C. showae * A. actino. b * S. noxia * **Small Green Oval (Bottom Left):** * E. corrodens * C. gingivalis * C. sputigena * C. ochracea * C. concisus * A. actino. a * **Red Oval (Far Right):** * P. gingivalis * T. forsythia * T. denticola Labelled diagram illustrating the Socransky microbial complexes in subgingival plaque. The visual consists of colored ovals representing different bacterial groups: a blue oval for Actinomyces species (top left), a purple oval for V. parvula and A. odontolyticus, a yellow oval for early colonizers like S. mitis and S. sanguis, a large orange central oval containing intermediate species like C. gracilis and F. nuc., a small green oval at the bottom left, and a red oval on the far right for late colonizers P. gingivalis, T. forsythia, and T. denticola. The presentation text is transcripted below. The pyramid on the left represents a classification of oral bacteria. <div style="text-align:justify;background-color:#fff;float:left;padding: 10px;margin-right: 10px;margin-bottom: 10px;"> T E H U N I V E R S I T Y O F WESTERN AUSTRALIA </div> <div style="clear:both;"></div> <div style="text-indent: 40px;background-color:#fff;float:left;padding: 0px;margin-right: 10px;margin-bottom: 10px;"> ...mondibilitas ... </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> C. gracilis C. rectus C. showae E. nodatum F. nuc. nucleatum P. intermedia P. micros P. nigrescens S. constellatus </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> P. gingivalis B. forsythus T. denticola </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> Actinomyces species </div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> V. parvula A. odontolyticus E. corrodens C. gingivalis C. sputigena C. ochracea C. concius A. actino.a </div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> S. mitis S. oralis S. sanguis Streptococcus spp. S. gordonii S. intermedius </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>Fig 9-4</b> The association among subgingival species. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> The different colors in the pyramid represent different bacterial complexes which are frequently detected in association with one another. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> The base of the pyramid represents the early stage of plaque development whereas the apex contains those organisms thought to be the last species to become established in the microbiota. The red complex of bacteria are those organisms frequently associated with sites of periodontal disease. <br> <br> (Source: Reprinted from Socransky & Haffajee 2002, with permission.) </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>Certain bacterial species</b> have been proposed to be protective or beneficial to the host, including **S. sanguis**, <b>Veillonella parvula</b>, and <i>C. Ochraceus</i> </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>S. sanguis</b> produce of H2O2 by; H2O2 is known to be lethal to cells of A. actinomycetemcomitans. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>Aggregatibacter actinomycetemcomitans</b> , the bacterium associated with rapidly progressive disease (molar Incisor pattern) in individuals of West African descent, <b>does not cluster with</b> the most disease-<b>associated red complex organisms</b>. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> The species most associated with periodontitis were <b>P. gingivalis</b>, <b>T. denticola</b>, <b>T. forsythia</b> (the three red complex species), and <b>Filifacor alocis</b>, a newly identified pathogen. (Note: OCR error corrected to Filifactor alocis based on context and common scientific knowledge, or kept as Filifacor alocis per OCR rules if sticking strictly to the text. Text says Filifacor alocis. I will output Filifacor alocis with bolding for the species name). </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <span style="color:orange"><b>Orange complex</b></span> and <span style="color:green"><b>few green complex</b></span> bacteria are Gingivitis associated bacteria. </div>  The presentation text is transcripted below. The pyramid on the left represents a classification of oral bacteria. <div style="text-align:justify;background-color:#fff;float:left;padding: 10px;margin-right: 10px;margin-bottom: 10px;"> T E H U N I V E R S I T Y O F WESTERN AUSTRALIA </div> <div style="clear:both;"></div> <div style="text-indent: 40px;background-color:#fff;float:left;padding: 0px;margin-right: 10px;margin-bottom: 10px;"> ...mondibilitas ... </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> C. gracilis C. rectus C. showae E. nodatum F. nuc. nucleatum P. intermedia P. micros P. nigrescens S. constellatus </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> P. gingivalis B. forsythus T. denticola </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> Actinomyces species </div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> V. parvula A. odontolyticus E. corrodens C. gingivalis C. sputigena C. ochracea C. concius A. actino.a </div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> S. mitis S. oralis S. sanguis Streptococcus spp. S. gordonii S. intermedius </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>Fig 9-4</b> The association among subgingival species. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> The different colors in the pyramid represent different bacterial complexes which are frequently detected in association with one another. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> The base of the pyramid represents the early stage of plaque development whereas the apex contains those organisms thought to be the last species to become established in the microbiota. The red complex of bacteria are those organisms frequently associated with sites of periodontal disease. <br> <br> (Source: Reprinted from Socransky & Haffajee 2002, with permission.) </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>Certain bacterial species</b> have been proposed to be protective or beneficial to the host, including **S. sanguis**, <b>Veillonella parvula</b>, and <i>C. Ochraceus</i> </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>S. sanguis</b> produce of H2O2 by; H2O2 is known to be lethal to cells of A. actinomycetemcomitans. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <b>Aggregatibacter actinomycetemcomitans</b> , the bacterium associated with rapidly progressive disease (molar Incisor pattern) in individuals of West African descent, <b>does not cluster with</b> the most disease-<b>associated red complex organisms</b>. </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> The species most associated with periodontitis were <b>P. gingivalis</b>, <b>T. denticola</b>, <b>T. forsythia</b> (the three red complex species), and <b>Filifacor alocis</b>, a newly identified pathogen. (Note: OCR error corrected to Filifactor alocis based on context and common scientific knowledge, or kept as Filifacor alocis per OCR rules if sticking strictly to the text. Text says Filifacor alocis. I will output Filifacor alocis with bolding for the species name). </div> <div style="clear:both;"></div> <div style="text-align: justify; background-color:#fff;float:left;padding:10px;margin-right:10px;margin-bottom:10px;"> <span style="color:orange"><b>Orange complex</b></span> and <span style="color:green"><b>few green complex</b></span> bacteria are Gingivitis associated bacteria. </div> A labelled diagram illustrating the Socransky classification of oral bacteria as a pyramid structure. The diagram shows four colored sections representing different bacterial complexes: a blue section at the base (Actinomyces species), a purple section above it (V. parvula, A. odontolyticus, E. corrodens, C. gingivalis, etc.), an orange section (S. mitis, S. oralis, S. sanguis, Streptococcus spp., S. gordonii, S. intermedius), and a red section at the apex (P. gingivalis, B. forsythus, T. denticola). Specific bacterial species names are listed next to each colored section. <table><thead><tr><th>Materia Alba</th><th>Dental Plaque</th><th>Calculus</th></tr></thead><tbody><tr><td> White, cheeseslike ac- cumulation </td><td>Resilient clear to yellow-grayish substance </td><td>Hard deposit that forms via the mineralization of dental plaque </td></tr><tr><td> Soft accumulation of salivary proteins, some bacteria, many desquamated epithelial cells, and occasional dis- integrating food debris </td><td>Primarily com- posed of bacteria in a matrix of sali- vary glycoproteins and extracellular polysaccharides </td><td>Generally covered by a layer of unmineralized dental plaque</td></tr><tr><td>Lacks an organized structure and is there- fore not as complex as dental plaque </td><td>Considered to be a biofilm</td><td></td></tr><tr><td>Easily displaced with a water spray </td><td>Impossible to remove by rinsing or with the use of sprays </td><td></td></tr></tbody></table>  <table><thead><tr><th>Materia Alba</th><th>Dental Plaque</th><th>Calculus</th></tr></thead><tbody><tr><td> White, cheeseslike ac- cumulation </td><td>Resilient clear to yellow-grayish substance </td><td>Hard deposit that forms via the mineralization of dental plaque </td></tr><tr><td> Soft accumulation of salivary proteins, some bacteria, many desquamated epithelial cells, and occasional dis- integrating food debris </td><td>Primarily com- posed of bacteria in a matrix of sali- vary glycoproteins and extracellular polysaccharides </td><td>Generally covered by a layer of unmineralized dental plaque</td></tr><tr><td>Lacks an organized structure and is there- fore not as complex as dental plaque </td><td>Considered to be a biofilm</td><td></td></tr><tr><td>Easily displaced with a water spray </td><td>Impossible to remove by rinsing or with the use of sprays </td><td></td></tr></tbody></table> A comparison table titled 'Differences Between Tooth Deposits' comparing three types of dental deposits: Materia Alba, Dental Plaque, and Calculus. The table is organized into four rows detailing characteristics such as appearance (e.g., 'White, cheeseslike accumulation' for Materia Alba vs. 'Hard deposit' for Calculus), composition (e.g., 'salivary proteins' vs. 'bacteria in a matrix'), structure (e.g., 'Lacks an organized structure' vs. 'Considered to be a biofilm'), and removability (e.g., 'Easily displaced with a water spray' vs. 'Impossible to remove by rinsing'). # Dental calculus - Dental calculus or tartar represents **mineralized bacterial biofilm**, although calculus formation can be induced in germ- free animals because of precipitation of mineral salts **originating from saliva**. - As the mineral content of dental biofilms increases, the biofilm mass becomes calcified to form calculus **Calculus** is frequently found in areas of the dentition adjacent to salivary ducts (e.g., the lingual surface of the mandibular incisors and canines, the buccal surface of the maxillary first molars), and this reflects. - **The high concentration of minerals available from saliva in those regions.** - The inorganic components of subgingival dental biofilms are derived from crevicular fluid (a serum transudate). - It should be noted that calculus continually harbors a viable bacterial biofilm. Dental calculus - Dental calculus or tartar represents **mineralized bacterial biofilm**, although calculus formation can be induced in germ- free animals because of precipitation of mineral salts **originating from saliva**. - As the mineral content of dental biofilms increases, the biofilm mass becomes calcified to form calculus **Calculus** is frequently found in areas of the dentition adjacent to salivary ducts (e.g., the lingual surface of the mandibular incisors and canines, the buccal surface of the maxillary first molars), and this reflects. - **The high concentration of minerals available from saliva in those regions.** - The inorganic components of subgingival dental biofilms are derived from crevicular fluid (a serum transudate). - It should be noted that calculus continually harbors a viable bacterial biofilm. University of Western Australia logo located in the top-left corner.   Clinical photograph showing the upper right quadrant of a patient's mouth. The image focuses on the teeth (molars) and gums. There is visible yellowish-brown calcified material (supragingival calculus) adhering to the outer surfaces of the teeth near the gumline. Clinical photograph showing the lower front teeth (anterior teeth). A significant amount of thick, yellowish-brown calculus covers the inner (lingual) surfaces of these teeth along the gumline. * Subgingivally, calculus may be found by **tactile exploration** only, since it is usually not visible to the naked eye. * Subgingival calculus is found in most periodontal pockets, usually extending from the cementoenamel junction to close to the bottom of the pocket.    * Subgingivally, calculus may be found by **tactile exploration** only, since it is usually not visible to the naked eye. * Subgingival calculus is found in most periodontal pockets, usually extending from the cementoenamel junction to close to the bottom of the pocket. Dental radiograph showing teeth with white arrows pointing to subgingival calculus deposits along the root surfaces. The image demonstrates that this calculus is not visible to the naked eye and requires tactile exploration for detection, as noted in the accompanying text. Clinical photograph of periodontal pockets showing inflamed gingiva and significant subgingival calculus deposits on the tooth roots. This visual supports the description that calculus extends from the cementoenamel junction towards the bottom of the pocket. Clinical photograph of clean teeth with healthy-looking gingiva, likely representing a post-treatment state or comparison to the diseased state shown above. It illustrates the contrast between the presence of calculus/inflammation and a cleaner condition. **Saudi Dental Journal** *(2020)* **32**, 80–85 --- King Saud University **Saudi Dental Journal** www.ksu.edu.sa www.sciencedirect.com **www.science.org</human> **المستند** **King Saud University** **الجمعية السعودية لطب الأسنان** **SAUDI DENTAL SOCIETY** --- **Effect of iatrogenic factors on periodontal health:** **An epidemiological study** Kankara Vinathi Reddy <span style="text-decoration: underline;">a</span>,*, Chembolu Nirupama <span style="text-decoration: underline;">a</span>, Pathakota Krishnajaneya Reddy <span style="text-decoration: underline;">a</span>, Pradeep Koppolu <span style="text-decoration: underline;">b</span>, Dalal H. Alotaibi <span style="text-decoration: underline;">c</span> **Conclusion:** This study clearly identified a higher prevalence, 50.8% of sub-gingival restorations causing gingivitis and has shown significant influence on periodontal status of the tooth. **Saudi Dental Journal** *(2020)* **32**, 80–85 --- King Saud University **Saudi Dental Journal** www.ksu.edu.sa www.sciencedirect.com **www.science.org</human> **المستند** **King Saud University** **الجمعية السعودية لطب الأسنان** **SAUDI DENTAL SOCIETY** --- **Effect of iatrogenic factors on periodontal health:** **An epidemiological study** Kankara Vinathi Reddy <span style="text-decoration: underline;">a</span>,*, Chembolu Nirupama <span style="text-decoration: underline;">a</span>, Pathakota Krishnajaneya Reddy <span style="text-decoration: underline;">a</span>, Pradeep Koppolu <span style="text-decoration: underline;">b</span>, Dalal H. Alotaibi <span style="text-decoration: underline;">c</span> **Conclusion:** This study clearly identified a higher prevalence, 50.8% of sub-gingival restorations causing gingivitis and has shown significant influence on periodontal status of the tooth. **Composition** **Inorganic Content** * Dental calculus is primarily composed of inorganic components (**70% to 90%**) and the organic components constitute the rest. * The major inorganic proportions of calculus are approximately * **76% calcium phosphate (Ca3[PO4]2)** * **3% calcium carbonate (CaCO3)** * **4% magnesium phosphate (Mg3[PO4]2)** * **2% carbon dioxide** * Traces of other elements such as sodium, zinc, strontium, bromine, copper, manganese, tungsten, gold, aluminum, silicon, iron, and fluorine. * The calcium concentration or content in plaque is **2 to 20 times higher than in saliva.** * The time required to reach the maximal level has been reported between **10 weeks & 6 months** <table> <caption> </caption> <thead> <tr> <th> Structure </th> <th> Inorganic Content (%) </th> </tr> </thead> <tbody> <tr> <td> Dental calculus </td> <td> 70–90 </td> </tr> <tr> <td> Enamel </td> <td> 96 </td> </tr> <tr> <td> Dentin </td> <td> 45 </td> </tr> <tr> <td> Bone </td> <td> 60–70 </td> </tr> </tbody> <tfoot> <tr> <td colspan="2"> <sup>*</sup>Organic components and water constitute the rest. </td> </tr> </tfoot> </table>  **Composition** **Inorganic Content** * Dental calculus is primarily composed of inorganic components (**70% to 90%**) and the organic components constitute the rest. * The major inorganic proportions of calculus are approximately * **76% calcium phosphate (Ca3[PO4]2)** * **3% calcium carbonate (CaCO3)** * **4% magnesium phosphate (Mg3[PO4]2)** * **2% carbon dioxide** * Traces of other elements such as sodium, zinc, strontium, bromine, copper, manganese, tungsten, gold, aluminum, silicon, iron, and fluorine. * The calcium concentration or content in plaque is **2 to 20 times higher than in saliva.** * The time required to reach the maximal level has been reported between **10 weeks & 6 months** <table> <caption> </caption> <thead> <tr> <th> Structure </th> <th> Inorganic Content (%) </th> </tr> </thead> <tbody> <tr> <td> Dental calculus </td> <td> 70–90 </td> </tr> <tr> <td> Enamel </td> <td> 96 </td> </tr> <tr> <td> Dentin </td> <td> 45 </td> </tr> <tr> <td> Bone </td> <td> 60–70 </td> </tr> </tbody> <tfoot> <tr> <td colspan="2"> <sup>*</sup>Organic components and water constitute the rest. </td> </tr> </tfoot> </table> Table comparing inorganic content percentages across different oral hard tissues (Dental calculus: 70–90%, Enamel: 96%, Dentin: 45%, Bone: 60–70%). Includes footnote stating organic components and water constitute the rest. • Formation • **Calculus** is mineralized dental plaque. • The soft plaque is hardened by the precipitation of mineral salts, which usually starts between the **1st and 14th day of plaque formation.** • Calcification has been reported to occur within as little as 4 to 8 hours. • Calcifying plaques may become **50% mineralized in 2 days and 60% to 90% mineralized in 12 days.** > **KEY FACT** > Calculus by itself does not contribute directly to gingival inflammation. Like other retentive factors, such as open crown margin or an overhanging restoration, calculus retains dental plaque, which contributes to gingival inflammation.  • Formation • **Calculus** is mineralized dental plaque. • The soft plaque is hardened by the precipitation of mineral salts, which usually starts between the **1st and 14th day of plaque formation.** • Calcification has been reported to occur within as little as 4 to 8 hours. • Calcifying plaques may become **50% mineralized in 2 days and 60% to 90% mineralized in 12 days.** > **KEY FACT** > Calculus by itself does not contribute directly to gingival inflammation. Like other retentive factors, such as open crown margin or an overhanging restoration, calculus retains dental plaque, which contributes to gingival inflammation. A boxed text figure labeled 'KEY FACT' containing a summary statement: Calculus by itself does not contribute directly to gingival inflammation. Like other retentive factors, such as open crown margin or an overhanging restoration, calculus retains dental plaque, which contributes to gingival inflammation. **Four modes of attachment have been described.** (1) Attachment by means of an organic pellicle on cementum is depicted in **Fig. 24.6** (2) Mechanical locking into surface irregularities, such as caries lesions or resorption lacunae, is illustrated in **Fig. 24.8.** (3) Close adaptation of the undersurface of calculus to depressions or gently sloping mounds of the unaltered cementum surface is shown in **Fig. 24.9.** (4) Penetration of bacterial calculus into cementum The reason for firm attachment to the tooth surface is the fact that the **pellicle beneath the bacterial biofilm also calcifies**. This, in turn, results in an intimate contact with enamel, cementum or dentin crystals    **Four modes of attachment have been described.** (1) Attachment by means of an organic pellicle on cementum is depicted in **Fig. 24.6** (2) Mechanical locking into surface irregularities, such as caries lesions or resorption lacunae, is illustrated in **Fig. 24.8.** (3) Close adaptation of the undersurface of calculus to depressions or gently sloping mounds of the unaltered cementum surface is shown in **Fig. 24.9.** (4) Penetration of bacterial calculus into cementum The reason for firm attachment to the tooth surface is the fact that the **pellicle beneath the bacterial biofilm also calcifies**. This, in turn, results in an intimate contact with enamel, cementum or dentin crystals Micrograph showing a close-up view of calculus attached to an organic pellicle layer on tooth surfaces. Labels indicate 'E' for an enamel void, 'P' for the pellicle, and 'CA' for calculus. The image demonstrates the mechanism described in point (1): attachment by means of an organic pellicle on cementum. Micrograph illustrating mechanical locking of calculus into surface irregularities. It shows calculus (CA) adhering to a cemental resorption area (CR), with surrounding cementum (C) and underlying dentin (D). This visual corresponds to point (2) regarding mechanical locking into surface irregularities like resorption lacunae. Scanning Electron Micrograph (SEM) displaying the undersurface of subgingival calculus. White arrows highlight impressions of cementum mounds embedded within the calculus structure. This figure visually supports point (3), demonstrating the close adaptation of calculus undersurfaces to gently sloping mounds of the unaltered cementum surface. **The University of Western Australia** **Fig. 8-23** Excess cement at the abutment-crown interface provides an ideal substrate for biofilm and calculus deposition and retention. Bacterial biofilm covers the entire surface of the cement, whereas calculus is present apical to the cement overhang. Detachment of the epithelium indicates pocket formation. The detachment of the apical-most portion of the epithelium, however, may represent an artifact due to histologic processing. Underdecalfied ground section.   **The University of Western Australia** **Fig. 8-23** Excess cement at the abutment-crown interface provides an ideal substrate for biofilm and calculus deposition and retention. Bacterial biofilm covers the entire surface of the cement, whereas calculus is present apical to the cement overhang. Detachment of the epithelium indicates pocket formation. The detachment of the apical-most portion of the epithelium, however, may represent an artifact due to histologic processing. Underdecalfied ground section. Clinical photograph showing the peri-implant region of an oral implant. The central metallic abutment is surrounded by pink gingival tissue. A significant accumulation of white/yellowish calculus (tartar) is visible at the base of the implant and along the gumline, demonstrating poor hygiene or lack of maintenance. Histological micrograph (ground section) stained with hematoxylin and eosin. The image displays soft tissue structures (pink/purple) adjacent to a dark, irregular area representing the abutment-crown interface containing excess cement. The caption identifies this as a case where excess cement promotes biofilm and calculus formation, leading to pocket formation indicated by epithelial detachment. <dental X-Ray showing bone damage and tooth loss> <dental X-Ray showing bone damage and tooth loss> University logo for The University of Western Australia located in the top-left corner. **References** CHAPTER 24 The Role of Dental Calculus and Other Local Predisposing Factors Vivek Thumbrigere-Math 1 James E. Hinrichs CHAPTER OUTLINE Calculus Supragingival and Subgingival Calculus Prevalence Composition Attachment to the Tooth Surface Formation Etiologic Significance | Materia Alba, Food Debris, and Dental Stains **Other Predisposing Factors** Iatrogenic Factors Margins of Restorations Malocclusion | Periodontal Complications Associated With Orthodontic Therapy Extraction of Impacted Third Molars Habits and Self-inflicted Injuries Smokeless Tobacco Radiation Therapy **Chapter 8** Dental Biofilms and Calculus Philip D. Marshall, Mariano Sanz Nikolaus P. Lang, and Dieter D. Bosshardt **1**Department of Oral Biology School of Dentistry, University of Leeds, UK **1**Faculty of Odontology, ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) Research Group, Complutense University of Madrid, Madrid, Spain and Department of Periodontology, Faculty of Dentistry, Institute of Clinical Dentistry, University of Oslo, Oslo, Norway **2**Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland CHAPTER 10 **Biofilm and Periodontal Microbiology** Wirm Teughels Magda Feres Sukirth M. Ganesan Mark David Gidley Yvonne L. Hernandez-Kapila Nicholas S. Jakubovics NEWMAN AND CARRANZA'S **CLINICAL PERIODONTOLOGY** AND **IMPLANTOLOGY** 14TH EDITION LINDHE'S SeventH Edition **CLINICAL** **PERIODONTOLOGY** and **IMPLANT DENTISTRY** Vol 1 Edited by Torleif Lindhe William F. Giannobile, Niklaus P. Lang, and Mariano Sanz John Wiley & Sons Sedghi L, DiMassa V, Harrington A, Lynch SV, Kapila YL. The oral microbiome: Role of key organisms and complex networks in health and disease. Periodontol 2000. 2021;87:107–131 **References** #### Chapter 24: The Role of Dental Calculus and Other Local Predisposing Factors - **Authors:** Vivek Thumbrigere-Math, James E. Hinrichs **Chapter Outline** - Calculus - Supragingival and Subgingival Calculus - Prevalence - Composition - Attachment to the Tooth Surface - Formation - Etiologic Significance - Materia Alba, Food Debris, and Dental Stains - **Other Predisposing Factors** - Iatrogenic Factors - Margins of Restorations - Malocclusion - Periodontal Complications Associated With Orthodontic Therapy - Extraction of Impacted Third Molars - Habits and Self-inflicted Injuries - Smokeless Tobacco - Radiation Therapy --- #### Chapter 8: Dental Biofilms and Calculus - **Authors:** Philip D. Marshall, Mariano Sanz, Nikolaus P. Lang, Dieter D. Bosshardt - **Affiliations:** - Department of Oral Biology, School of Dentistry, University of Leeds, UK - Faculty of Odontology, ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) Research Group, Complutense University of Madrid, Madrid, Spain; and Department of Periodontology, Faculty of Dentistry, Institute of Clinical Dentistry, University of Oslo, Oslo, Norway - Department of Periodontology, School of Dental Medicine, University of Bern, Bern, Switzerland --- #### Chapter 10: Biofilm and Periodontal Microbiology - **Authors:** Wirm Teughels, Magda Feres, Sukirth M. Ganesan, Mark David Gidley, Yvonne L. Hernandez-Kapila, Nicholas S. Jakubovics --- #### Source Texts - Newman and Carranza's **Clinical Periodontology** and **Implantology**, 14th Edition - Lindhe's **Clinical Periodontology** and **Implant Dentistry**, Seventh Edition, Vol 1, Edited by Torleif Lindhe, William F. Giannobile, Niklaus P. Lang, and Mariano Sanz, John Wiley & Sons --- #### Reference - Sedghi L, DiMassa V, Harrington A, Lynch SV, Kapila YL. The oral microbiome: Role of key organisms and complex networks in health and disease. *Periodontol 2000*. 2021;87:107–131 [^1]: Original PDF page 1: [[L4 Etiopathogenesis part 1.pdf#page=1|L4 Etiopathogenesis part 1, p.1]] [^2]: Original PDF page 2: [[L4 Etiopathogenesis part 1.pdf#page=2|L4 Etiopathogenesis part 1, p.2]] [^3]: Original PDF page 3: [[L4 Etiopathogenesis part 1.pdf#page=3|L4 Etiopathogenesis part 1, p.3]] [^4]: Original PDF page 4: [[L4 Etiopathogenesis part 1.pdf#page=4|L4 Etiopathogenesis part 1, p.4]] [^5]: Original PDF page 5: [[L4 Etiopathogenesis part 1.pdf#page=5|L4 Etiopathogenesis part 1, p.5]] [^6]: Original PDF page 6: [[L4 Etiopathogenesis part 1.pdf#page=6|L4 Etiopathogenesis part 1, p.6]] [^7]: Original PDF page 7: [[L4 Etiopathogenesis part 1.pdf#page=7|L4 Etiopathogenesis part 1, p.7]] [^8]: Original PDF page 8: [[L4 Etiopathogenesis part 1.pdf#page=8|L4 Etiopathogenesis part 1, p.8]] [^9]: Original PDF page 9: [[L4 Etiopathogenesis part 1.pdf#page=9|L4 Etiopathogenesis part 1, p.9]] [^10]: Original PDF page 10: [[L4 Etiopathogenesis part 1.pdf#page=10|L4 Etiopathogenesis part 1, p.10]] [^11]: Original PDF page 11: [[L4 Etiopathogenesis part 1.pdf#page=11|L4 Etiopathogenesis part 1, p.11]] [^12]: Original PDF page 12: [[L4 Etiopathogenesis part 1.pdf#page=12|L4 Etiopathogenesis part 1, p.12]] [^13]: Original PDF page 13: [[L4 Etiopathogenesis part 1.pdf#page=13|L4 Etiopathogenesis part 1, p.13]] [^14]: Original PDF page 14: [[L4 Etiopathogenesis part 1.pdf#page=14|L4 Etiopathogenesis part 1, p.14]] [^15]: Original PDF page 15: [[L4 Etiopathogenesis part 1.pdf#page=15|L4 Etiopathogenesis part 1, p.15]] [^16]: Original PDF page 16: [[L4 Etiopathogenesis part 1.pdf#page=16|L4 Etiopathogenesis part 1, p.16]] [^17]: Original PDF page 17: [[L4 Etiopathogenesis part 1.pdf#page=17|L4 Etiopathogenesis part 1, p.17]] [^18]: Original PDF page 18: [[L4 Etiopathogenesis part 1.pdf#page=18|L4 Etiopathogenesis part 1, p.18]] [^19]: Original PDF page 19: [[L4 Etiopathogenesis part 1.pdf#page=19|L4 Etiopathogenesis part 1, p.19]] [^20]: Original PDF page 20: [[L4 Etiopathogenesis part 1.pdf#page=20|L4 Etiopathogenesis part 1, p.20]] [^21]: Original PDF page 21: [[L4 Etiopathogenesis part 1.pdf#page=21|L4 Etiopathogenesis part 1, p.21]] [^22]: Original PDF page 22: [[L4 Etiopathogenesis part 1.pdf#page=22|L4 Etiopathogenesis part 1, p.22]] [^23]: Original PDF page 23: [[L4 Etiopathogenesis part 1.pdf#page=23|L4 Etiopathogenesis part 1, p.23]] [^24]: Original PDF page 24: [[L4 Etiopathogenesis part 1.pdf#page=24|L4 Etiopathogenesis part 1, p.24]] [^25]: Original PDF page 25: [[L4 Etiopathogenesis part 1.pdf#page=25|L4 Etiopathogenesis part 1, p.25]] [^26]: Original PDF page 26: [[L4 Etiopathogenesis part 1.pdf#page=26|L4 Etiopathogenesis part 1, p.26]] [^27]: Original PDF page 27: [[L4 Etiopathogenesis part 1.pdf#page=27|L4 Etiopathogenesis part 1, p.27]] [^28]: Original PDF page 28: [[L4 Etiopathogenesis part 1.pdf#page=28|L4 Etiopathogenesis part 1, p.28]] [^29]: Original PDF page 29: [[L4 Etiopathogenesis part 1.pdf#page=29|L4 Etiopathogenesis part 1, p.29]] [^30]: Original PDF page 30: [[L4 Etiopathogenesis part 1.pdf#page=30|L4 Etiopathogenesis part 1, p.30]] [^31]: Original PDF page 31: [[L4 Etiopathogenesis part 1.pdf#page=31|L4 Etiopathogenesis part 1, p.31]] [^32]: Original PDF page 32: [[L4 Etiopathogenesis part 1.pdf#page=32|L4 Etiopathogenesis part 1, p.32]] [^33]: Original PDF page 33: [[L4 Etiopathogenesis part 1.pdf#page=33|L4 Etiopathogenesis part 1, p.33]] [^34]: Original PDF page 34: [[L4 Etiopathogenesis part 1.pdf#page=34|L4 Etiopathogenesis part 1, p.34]] [^35]: Original PDF page 35: [[L4 Etiopathogenesis part 1.pdf#page=35|L4 Etiopathogenesis part 1, p.35]] [^36]: Original PDF page 36: [[L4 Etiopathogenesis part 1.pdf#page=36|L4 Etiopathogenesis part 1, p.36]] [^37]: Original PDF page 37: [[L4 Etiopathogenesis part 1.pdf#page=37|L4 Etiopathogenesis part 1, p.37]] [^38]: Original PDF page 38: [[L4 Etiopathogenesis part 1.pdf#page=38|L4 Etiopathogenesis part 1, p.38]] [^39]: Original PDF page 39: [[L4 Etiopathogenesis part 1.pdf#page=39|L4 Etiopathogenesis part 1, p.39]]