L4 Infectious disease in dental practice 2025_formatted_text

DENT 3005: Introduction to Pharmacology¹

Infection control in dental practice

Dr Thuy Linh Truong thuy.truong@uwa.edu.au

Acknowledgement of country²

The University of Western Australia acknowledges that its campus is situated on Noongar land, and that Noongar people remain the spiritual and cultural custodians of their land, and continue to practise their values, languages, beliefs and knowledge.

Artist: Dr Richard Barry Walley OAM

THE UNIVERSITY OF WESTERN AUSTRALIA

Learning Objectives³

1. Explain pathogenicity and virulence of oral microorganisms
2. Identify sources and routes of infection transmission in dentistry
3. Broadly understand the key microbial virulence factors and their effects
4. Discuss the role of vaccines in preventing communicable diseases
5. Apply infection control principles in dental practice
6. Understand the role of pharmacological agents appropriately to manage oral infections

Pathogenicity and Virulence of Microorganisms⁴

• Pathogenicity refers to a microorganism’s ability to cause disease
• Virulence refers to the degree or severity of the disease a pathogen can cause

Key virulence factors

Virulence Factor	Function	Example
Adhesins	Enable bacteria to attach to host tissues	Streptococcus mutans in dental plaque
Invasins	Allow penetration into tissues	Listeria monocytogenes
Toxins	Damage or kill host cells	Clostridium tetani, E. coli
Enzymes	Degrade tissue, aid spread	Collagenase, hyaluronidase
Immune Evasion	Avoid detection or destruction	Capsule in Streptococcus pneumoniae

Sources of Infection and Routes of Transmission⁵

Sources of infection

• Patients: carriers of bacteria, viruses (e.g., HBV, HCV, HIV)
• Dental instruments and surfaces: if improperly sterilized
• Aerosols and droplets: generated during dental procedures

Routes of transmission

• Direct contact: with blood, saliva, or mucosa
• Indirect contact: via contaminated instruments, gloves, or surfaces
• Droplet transmission: coughing, sneezing, ultrasonic scalers
• Airborne: fine aerosols staying suspended and inhaled
• Sharps injuries: needle-stick or instrument-related injuries

Infection control in dental practices⁶

• Personal Protective Equipment (PPE)
• Hand hygiene
• Sterilization of instruments
• Surface disinfection
• Proper waste disposal
• Vaccination of staff

Role of vaccines in preventing infectious diseases⁷

• Vaccines stimulate the immune system to develop memory against specific pathogens without causing disease

Important vaccines for dental professionals

• Hepatitis B (mandatory for dental workers)
• Influenza (annual)
• COVID-19
• Tetanus, Diphtheria, Pertussis
• Measles, Mumps, Rubella (MMR)

Mechanism of action

• Vaccines introduce antigens that mimic the pathogen, leading to an immune response. This results in antibody production and immune memory.

Pharmacological considerations in infectious disease management⁸

• Antibiotic prophylaxis: for selected patients at risk of infective endocarditis before invasive dental procedures
• Antiviral medications: management of oral herpes or HIV-related conditions
• Antifungals: for treating oral candidiasis (e.g., nystatin, fluconazole)
• Vaccination history review: consider interactions with immunosuppressive medications or compromised immune states

Take home message⁹

• Microorganisms cause disease through pathogenicity and virulence
• Understanding transmission routes is essential for infection control in clinical settings
• Vaccines are a vital preventive tool for both practitioners and patients
• Pharmacological interventions (antibiotics, antifungals, antivirals) support infection management
• Clinical decisions must always balance efficacy, patient comfort, and safety

Review¹⁰¹¹

References

• Bowen WH, Koo H. Biology of Streptococcus mutans-derived glucosyltransferases: Role in extracellular matrix formation of cariogenic biofilms. Caries Res. 2011;45(1):69–86. Available from: https://www.sciencedirect.com/science/article/pii/S1882761617300066
• Kaiser GE. The ability to invade host cells. In: Microbiology [Internet]. LibreTexts; 2023 [cited 2025 Apr 10]. Available from: https://bio.libretexts.org/Bookshelves/Microbiology/Microbiology_(Kaiser)/Unit_3%3A_Bacterial_Pathogenesis/5%3A_Virulence_Factors_that_Promote_Colonization/5.3%3A_The_Ability_to_Invade_Host_Cells
• Australian Commission on Safety and Quality in Health Care. Options for implementation of preventing and controlling infections in primary care: dental practice [Internet]. Sydney: ACSQHC; 2024 [cited 2025 May 3]. Available from: https://www.safetyandquality.gov.au/sites/default/files/2024-12/options_for_implementation_of_preventing_and_controlling_infections_in_primary_care_dental_practice.pdf
• Tortora GJ, Funke BR, Case CL. Microbiology: An Introduction, Global Edition. 13th ed. Pearson; 2019
• Australian Commission on Safety and Quality in Health Care. National Hand Hygiene Initiative Implementation Guide. Sydney: ACSQHC; 2024. Available from: https://www.safetyandquality.gov.au/sites/default/files/2023-07/nhhi_implementation_guide_july_2023.pdf
• Australian Technical Advisory Group on Immunisation (ATAGI). Australian Immunisation Handbook [Internet]. Canberra: Australian Government Department of Health and Aged Care; 2024 [cited 2025 Apr 10]. Available from: https://immunisationhandbook.health.gov.au/

Footnotes

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