Complete Dentures¹

Preclinical

An Overview

Note

This lecture serves as an introduction to the complete denture module, covering the theory and practice of complete denture fabrication. The primary focus is on understanding edentulism (tooth loss), its epidemiology, and its profound impact on the health and quality of life of patients. Complete dentures are a common treatment modality to manage this debilitating and irreversible condition.

Edentulism²

Debilitating and irreversible condition
Final marker of disease burden for oral health
Prevalence has declined over the last few decades
Remains a major disease worldwide (especially among older adults)
Prevalence varies both intra-country and inter-country.
Contributing factors may be:
- Economic circumstances
- Education
- Lifestyle
- Oral health knowledge & beliefs
- Access and attitudes to dental care
- Age
- Insurance coverage

Edentulism can lead directly to impairment, functional limitation, physical, psychological, and social disability

Oral rehabilitation with complete dentures can restore chewing, phonetics, aesthetics, self-esteem and dignity of the patient

Edentulism²

Causes of Tooth Loss

Dental Caries (63%)
This is the dominant reason for tooth extraction in patients within the 20-30 year age group.
Periodontal Disease (20%)
This accounts for the majority of tooth extractions in patients older than 40 years.
Dental Trauma
Congenital Disorders
e.g. Ectodermal dysplasia
Parafunction
Smoking

Epidemiology of Tooth Loss³

No simple association between edentulism and socio-economic and socio-demographic indicators.

==Global Trends:==
- ==In developed countries, the percentage of edentulism has decreased over the last 20 years.==
- ==In developing countries, the rate is increasing, often because painful teeth are extracted rather than being treated conservatively.==
- The overall number of edentulous individuals continues to grow due to population aging and increasing life expectancy.
==Socioeconomic Examples:==
- ==Hong Kong: GDP per capita of ~$25,000 USD, edentulism rate of ~16%.==
- ==United Kingdom: Similar GDP, but an edentulism rate of ~37%.==
- ==Kenya: GDP per capita of ~$2,000 USD, edentulism rate approaching 0% (possibly due to shorter life expectancy).==
==The dentist-to-population ratio does not necessarily reduce edentulism.==
- ==Iceland: 10 dentists per 10,000 inhabitants, edentulism rate of ~72%.==
- ==Kenya & Nigeria: ~0.3 dentists per 10,000 inhabitants, edentulism rate near 0%.==

Marked ethnic disparities in edentulism and tooth loss have been demonstrated in various parts of the world.

Info

Numerous studies hypothesize that edentulism is more prevalent in women than in men.

e.g. in New Zealand: Maori women 5 times more likely to be edentulous than Caucasian women.

In studies from the 1990’s rates of edentulism were estimated to be between 7% and 69% of the adult population internationally.

The loss of teeth is associated with compromised oral function and loss of social status as well as diminished self-esteem.

Carlsson, G. E., 2010

Impact of Edentulism on Patient’s Health⁴⁵

Oral Health

General Health

Quality of life⁶

Impact of Edentulism on Oral Health

Oral Health

1. Tooth loss: modifier of normal physiology

Alveolar bone loss follows tooth loss
The primary function of alveolar bone is to support teeth. Following tooth loss, the bone is no longer subjected to functional stresses and begins to resorb.
- ==This process is rapid at first (40 days after extraction, the ridge height can decrease by about one-third) but continues over time until only basal bone remains.==
- The mandible generally has higher alveolar density than the maxilla due to greater cortical thickness, which has implications for dental implant placement.
Height of residual ridge and size of denture bearing area are both reduced
- High
  - AB = AC > BC
- Normal
  - AB = AC = BC
- Low
  - AB = AC < BC
- Size of Denture Bearing Area
  - periodontium / arch 45 cm²
  - edentulous maxilla 23 cm²
  - edentulous mandible 12 cm²
Face height and facial appearance

2. Tooth loss: risk factor for impaired mastication⁷⁸⁹¹⁰

Oral function and health related to number of functional tooth units
Reduced bite strength and masticatory force (by 1/5 to 1/4)
Complete denture wearers require seven times more chewing strokes than dentate individuals
Muscular atrophy associated with edentulism

Elders with poorer mastication had:

Significantly lower cognitive function.
A steeper cognitive decline.
Associations with dementia cross-sectionally
An increased risk for incidence of dementia longitudinally.

3. Tooth loss: determinant of oral health¹¹

Edentulism associated with functional and sensory deficiencies of oral mucosa, musculature and sensory glands
Decreased tissue regeneration and decreased tissue resistance lowers protective function of oral mucosa
Increased rate of mucosal disorders (angular cheilitis, denture stomatitis, candidiasis or traumatic ulcers)
May induce oral dyskinesia

Emami et al, 2013

Impact of Edentulism on General Health¹²

General Health

Dietary changes
Patients often avoid foods that are difficult to chew.
- Lower intake of fruits, vegetables, fibre and carotene
- Increased cholesterol and saturated fats
- Higher prevalence of obesity
Alterations to the GI tract
Poorly digested food can cause chronic inflammation of the gastric mucosa.
- Chronic inflammatory changes of the gastric mucosa
- Upper gastrointestinal and pancreatic cancer
- Higher rates of peptic or duodenal ulcers
Increased risk of non-insulin dependent diabetes mellitus
- Excessive intake of highly processed high-fat and high-carbohydrate foods
Increased risk of cardiac issues
- Hypertension
- Heart failure
- Ischaemic heart disease
- Stroke
- Aortic valve stenosis
Increased risk of chronic kidney disease
Association between edentulism and sleep-disordered breathing

Tooth loss in edentulous individuals was found to be associated with the onset of disability and mortality, even after adjusting for confounding factors such as socioeconomic and health behaviour factors. Emami et al 2013

Impact of Edentulism on Quality of Life¹³

Quality of life⁶

Quality of Life - is defined as an individual’s perception of his or her position in life, in the context of the culture and value systems in which they live, and in relation to their goals, expectations, and concerns.

Perception of QoL - varies among individuals and fluctuates over time for the same person as a result of changes in any of its component parts

Patient’s perceptions of QoL - are important in evaluating efficacy of oral health care and are influenced by:

Aesthetic concerns
Speech issues
Impaired mastication
Dental trauma
Social life
Decreased self esteem
Altered taste

Clinical measures of treatment efficacy - provide little insight into psychosocial aspects of health

Warning

A clinician may judge a prosthesis to be clinically satisfactory, but the patient may find it completely unsuitable. Patient perceptions of QoL are crucial for evaluating the true efficacy of oral healthcare.

Factors Affecting Denture Satisfaction¹⁴

drugs → salivary flow → denture retention
==Prescription or non-prescription drugs that cause xerostomia (dry mouth) can negatively affect salivary flow, reducing denture retention and comfort.==
systemic factors → neurological disorders
- e.g. Parkinson disease → denture retention and neuromuscular control
oral manifestations of systemic illnesses → e.g. Sjögren’s syndrome → denture retention and comfort
psychological factor
- personality → neuroticism → denture dissatisfaction
Personality traits leading to neuroticism can cause patients to be hypercritical of their dentures, making them extremely difficult to treat successfully.

Complete Denture Overview¹⁵

It is important to remember that:

Complete dentures are not a substitute for the natural dentition. They are an alternative to edentulism

Edentulism²

Note

Edentulism is defined as the state of being toothless.

Evolution of Complete Dentures

==Early Prostheses: Some of the earliest attempts involved using extracted natural teeth set in a carved ivory or metallic frame, such as the dentures made for George Washington.==
==Vulcanite (1850s - 1930s): Vulcanite, a sulfur-hardened rubber, became common in the 1860s. It was heat-cured under pressure but was porous and collected plaque easily.==
==Acrylic Resin (1930s - Present): Polymethyl methacrylate (PMMA) superseded vulcanite. It was also heat-cured and offered superior aesthetics and hygiene.==
==Digital Era: Modern dentures can be fabricated using digital technology:==
- ==Milled Dentures: Machined from a solid block (e.g., a bicolor disc) of resin.==
- ==3D Printed Dentures: The denture base is printed, and artificial teeth are subsequently bonded to it, either individually or as a block.==

Complete Denture Overview¹⁵

Stages of Conventional Denture Fabrication¹⁶

Anatomical Impression

==Made using stock trays that approximate the patient’s jaw shape.==
Dentist: Taking the impression.
Anatomical models: Pouring the impression and completing the anatomical models (Upper model shown).
==These are also known as preliminary working casts.==

Functional Impression Tray

Fabrication of the functional impression tray made of self-curing acrylic.

Functional Impression

Info

A selective pressure impression is made to capture fine detail of the denture-bearing tissues in a functional state.

Dentist: Performing the functional impression using kinetic movement (muscle trimming).

Functional Models

==The functional impression is poured in Type 3 dental stone to create the final master casts.==
Marking the functional borders on the functional impression.
Trim model up to the marking.

Bite rims¹⁷

==Upper and lower base plates are made on the master casts, and wax rims are attached.==
At the chairside, these rims are adjusted to establish proper lip support, facial contours, and vertical dimension.
==Registration paste is used to record the relationship between the upper and lower jaws (bite registration).==
Fabrication of the bite rims on the functional models
Upper (ULB)
Mimetic movement (muscle trimmed)

Articulation and Tooth Setup

==The casts and rims are mounted on an articulator, an instrument that simulates jaw movements.==
Artificial teeth are set in the wax rims according to functional and aesthetic requirements.

Trial Insertion¹⁸¹⁹²⁰²¹²²

==The

graph TD
    A[Anatomical impression] --> B[Anatomical models]
    B --> C[Functional impression tray]
    C --> D[Functional impression]
    D --> E[Functional models]
    E --> F[Bite rims]
    F --> G[Bite recording]
    G --> H[Mounting on the articulator]
    H --> I[Tooth selection]
    I --> J[Setup of the teeth]
    J --> K[Waxing]
    K --> L[Investing]
    L --> M[Packing and pressing]
    M --> N[Polymerization]
    N --> O[Finishing]
    O --> P[Final check]

    subgraph "Anatomical Impression & Models"
        A -->|Dentist| A1(Pouring the impression and completing the anatomical models)
    end

    subgraph "Functional Impression & Models"
        C -->|Fabrication of the functional impression tray made of self curing acrylic| C1
        D -->|Dentist| D1(Mimetic movement (muscle trimming))
        E -->|Marking the functional borders on the functional impression| E1
        E -->|Trim model up to the marking| E2
        F -->|Fabrication of the bite rims on the functional models| F1
    end

    subgraph "Bite Recording & Mounting"
        G -->|Dentist| G1(Occlusal height)
        H --> H1
    end

    subgraph "Tooth Selection & Setup"
        I -->|Dentist| I1(According to sex, type, jaw shape and colour)
        I1 --> I2(Male)
        I1 --> I3(Female)
        J --> J1(A: in the posterior area<br>B: in the anterior area)
    end

    subgraph "Waxing & Try-in"
        K --> K1(Try-in by dentist)
    end

    subgraph "Processing"
        L --> L1(Completed wax up invested<br>Roll out Separator Applications)
        M --> M1
        N --> N1(Time, Temperature)
        N --> N2(Pressing)
        O --> O1
        P --> P1(Issue of the denture<br>Dentist)
    end

Complete Denture Overview¹⁵

Treatment Alternatives

Do Nothing
Overdenture
A denture that rests on and is retained by a few remaining natural teeth or by dental implants.
All-on-Four
==This is a type of Implant-Supported Complete Bridge, a fixed prosthesis that is fully supported by multiple dental implants, not by the soft tissue.==

Digital Workflows for Immediately-placed Implant-Supported Prostheses

Immediately Loaded Implant-Supported Bridge(s)

A workflow where the bridge is designed and fabricated prior to surgery and is attached at the time of, or shortly after, implant placement.

Treatment Planning²³

Poor planning can have unanticipated consequences

George Stathakis

A 46 year old bachelor and chef decided to go over the Niagara Falls in July, 1930 in a massive self-made barrel. His intention was to generate revenue to publish a book on his metaphysical experiences.

The barrel, which was 5 ft in diameter, ten feet long and weighed a ton, survived the 170 ft plunge but became trapped behind the falls for twenty hours.

Sadly, when the barrel was recovered George had died from suffocation but his 150 year old pet turtle survived.

This story illustrates the principle of the 5 P's:

Proper Planning Prevents Poor Performance

Complete Denture Overview¹⁵

Treatment Schedule

Info

The current protocol for complete denture fabrication in the student clinic follows a six-visit sequence, outlining procedures performed in the clinic and those undertaken in the laboratory. This schedule may evolve as digital procedures are progressively introduced.

Visit	Operator	Procedure
Visit 1	Clinician Laboratory	Patient evaluation & primary impressions Diagnostic casts & special trays
Visit 2	Clinician Laboratory	Secondary impressions Bead & box, master casts, base & rims
Visit 3	Clinician Laboratory	Contour rims, OVD, MMR, shade & mould selection Articulation & tooth setting
Visit 4	Clinician Laboratory	Wax try-in Finalisation & processing
Visit 5	Clinician	Assessment & issue Instructions for care
Visit 6	Clinician	Post operative review, post insertion instructions

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Quartz 4

Explorer

L1 Complete Dentures Overview

Complete Dentures1

Preclinical

Edentulism2

Edentulism2

Causes of Tooth Loss

Epidemiology of Tooth Loss3

Impact of Edentulism on Patient’s Health45

Oral Health

General Health

Quality of life6

Impact of Edentulism on Oral Health

Oral Health

1. Tooth loss: modifier of normal physiology

2. Tooth loss: risk factor for impaired mastication78910

3. Tooth loss: determinant of oral health11

Impact of Edentulism on General Health12

General Health

Impact of Edentulism on Quality of Life13

Quality of life6

Factors Affecting Denture Satisfaction14

Complete Denture Overview15

Edentulism2

Evolution of Complete Dentures

Complete Denture Overview15

Stages of Conventional Denture Fabrication16

Anatomical Impression

Functional Impression Tray

Functional Impression

Functional Models

Bite rims17

Articulation and Tooth Setup

Trial Insertion1819202122

Complete Denture Overview15

Treatment Alternatives

Digital Workflows for Immediately-placed Implant-Supported Prostheses

Treatment Planning23

George Stathakis

Complete Denture Overview15

Treatment Schedule

Footnotes

Graph View

Table of Contents

Backlinks

Complete Dentures¹

Edentulism²

Edentulism²

Epidemiology of Tooth Loss³

Impact of Edentulism on Patient’s Health⁴⁵

Quality of life⁶

2. Tooth loss: risk factor for impaired mastication⁷⁸⁹¹⁰

3. Tooth loss: determinant of oral health¹¹

Impact of Edentulism on General Health¹²

Impact of Edentulism on Quality of Life¹³

Quality of life⁶

Factors Affecting Denture Satisfaction¹⁴

Complete Denture Overview¹⁵

Edentulism²

Complete Denture Overview¹⁵

Stages of Conventional Denture Fabrication¹⁶

Bite rims¹⁷

Trial Insertion¹⁸¹⁹²⁰²¹²²

Complete Denture Overview¹⁵

Treatment Planning²³

Complete Denture Overview¹⁵