Department of ORAL MEDICINE

Infection Control in

Dental Practice

By

Antony Sebastian Ullattil,

C.R.I.

Introduction

Objective

Patient perception and need for infection control

Infection control in your dental office

OSHA regulation

Universal prevention

Methods of infection control

Disposal of wastes

Introduction

Why do we need to know about infection control ?

The goal of infection control is to eliminate or reduce the number of microbes shared between people.

Implementing safe and realistic infection control procedures requires the full compliance of the whole dental team.

Patient perception and need for infection control.

• It is the duty of every dental practitioner to cure for all patients including those with infections diseases.

• As a result of frequent medical coverage the public is now aware of the need for dentist to practice good infection control.

• Displaying an infection control statement may be helpful to really patient anxiety and gain their confidence.

Routine Procedures.

Through medical history

Asymptomatic carriers

Acceptance of patient

It is unethical to refuse dental care to

those patient with a potentially infections

disease on the grounds that it could

expose the dental clinician to personal

risk.

Confidentiality – Those with HIV infection

Infected dental health care locker most avoid exposure prone procedures.

Exposure risk and effect of infection on

dentistry.

Every health care specialty that

involves contact with mucosa blood or

blood contaminated body fluid is now

regulated.

The goal is to ensure compliance

with universal barriers and other

methods to minimize infection risks.

Environment of dental office

Ventilation – The recommended fresh air supply rate of ventilation systems should not fall below 5-8 liters per second per occupant.

Recycling air conditioning systems are not recommended.

Floor Covering

The floor covering should be impervious and non slippery.

Carpet must be avoided.

Air borne contamination

High speed hand piece is capable of creating air borne contaminants from bacterial residents from saliva.

Aerosols

Particle size range from 50 um to approximately 5 um. That can remain suspended in the air and breathed for hrs.

Cross infections.

Patients infected usually are not aware of the source of their infection.

Personal Vulnerability

Immunization - Hepatitis B infection

Anti – HBs levels must be measured 2-4 months after complete immunization course.

HBS level > 100 M/U/ml will provided adequate protection.

Single booster dose 5 years after completion of primary course is recommended for all health care workers.

Concept of Infection

The number of organisms required to cause an infection is termed as “The infective dose”.

Infections diseases of concern in dentistry.

Bacteria Viruses

N.Gonorrhoeae Hepatitis B,C,D

T. Pallidum H.I.V.

M. Tuberculosis Cytomegalo virus

Strep. Pyogenes Measles

Mumps

Rubella

Herpes

General Principles

Universal precautions – use of mouth mask, head cap, protective eye were gloves are recommended.

Hand washing and care of hands

Sir William Osler once remarked that Soap and water and common sense are the best disinfectants.

Use of commonly available antiseptic hand wash like chlorhexidine is generally enough.

OSHA (Occupational safety and Health agency) regulation.

Exposure and control plan

Emergency and exposure incident plan

OSHA required records.

Methods of Infection control

Sterilization – Sterilization is the destruction or complete removal of all forms of micro organisms.

Disinfection – Disinfection is the destruction of many microorganisms but not usually the bacterial spores.

Choice of equipments

Choice of equipments depends upon the requirement of the practioner.

Water supplies

The ADA council on scientific affairs recommends to improved the design of dental equipment of that water delivered to patients during non surgical dental procedures contains no more than 200 colony forming units / ml (cfu/ml) of bacteria at any point of time in the unfiltered output of dental unit.

Pre-Sterilization Cleaning

Bio-films of vegatitive form of bacterias spores and the organic matter formed on the surface of the instrument have to be washed with the suitable disinfectant before proceeding with the sterilization process.

Physical agents

Heat – Moist, Dry

Ionizing radiations

X-rays, beta rays

gamma rays

Ultraviolet rays

Filtration

Chemical agents

Agents acting on cell membrane

Surface acting agents, Phenols, Organic solvents

Agents that denature proteins

Acids and alkalies

Agents acting on functional group of proteins

Heavy metals

Oxidizing agents, Dyes, Alkylating agents.

STERILIZATION

Steam Pressure Sterilization (Autoclaving)

Long cycle of 15 min – 121 degree Celsius and 15 lbs pressure.

Short cycle of 7 min – 134 degree Celsius and 30 lbs pressure.

Advantage of autoclaves - Most rapid and effective methods for sterilization of commonly used dental equipments.

Disadvantages of Autoclaves – Can cause rusting of carbon steel instruments.

Dental burs can be autoclaved after dipping it into 2 % sodium nitrite sol.

Dry Heat Sterilization – Hot air oven

Dry heat at 160 degree Celsius for commonly used for this purpose. Microbial inactivation by dry heat is primarily an oxidation process.

Employed for sterilization of glassware, glass syringes, oils and oily injection as well as metal instruments.

Chemiclaving – Using ethylene oxide gas

131 degree celcius 20 pounds pressure is use for this purpose. Heat sensitive plastic instrument are sterilized by this method.

New methods of sterilization

Using - ultra violet light and gamma rays

Not effective against RNA viruses like HIV and bacterial spores.

Ultrasonic sterilization.

Not commonly employed in dental practice.

Glass bead sterilizer – used for sterilization of endodontic files.

Types of instruments and sterilization methods.

Hand piece – Should be well disinfected before sterilization

Hot oil sterilization can be used for this.

Autoclaving is commonly carried out.

Sterilization of impression (Vinyl Polysiloxane) or Rubber – Based Impression. – These are sterilized by dipping them in 2 % gluteraldehyde solution for minimum of 2 hours.

These should be wrapped in sterile bag.

Disposal of waste / infected material

Waste material are first assorted as infected or and non infected.

They are then accordingly disposed of into color coated bags. – yellow, red, blue/white, translucent, black.

Sharp objects like BP Blades are disposed of into puncture proof metal boxes.

Needled are destroyed using needle destroyer.

Use of disposable needled – syringes are preferable.

Mercury containing amalgam wastes are disposed of into sulphide solution.

Needle stick injury – one of the most common hazard which dental professional and other medical professional usually come across.

The risk of transmission of HIV and Hepatitis B is most dangerous.

For Hepatitis B – It is always better for any health care worker to be well vaccinated with HBs vaccine.

For HIV – as soon as one comes across needle stick injury –

1. Hands should be washed thoroughly with the available disinfectant.

2. The area of the injury should be squeezed of for allowing blood to flow out of it.

3. The patient can be ask for his HIV or Hepatitis B status.

4. The senior medical incharge should be informed about the accident.

5. HIV postexposure chemoprophylaxis for health workers.

Basic (28 days) – Zidovudine + Lamivudine

Expanded (28 days) – As above + Indinavir or nelfinavir or neviriapine

6. PCR – (polymerized chain reaction) can detect the presence of HIV – p24 antigen within 24 hrs of initial infection.

7. Check up with ELISA in every six months.

8. The risk of HIV transmission by needle stick injury is only 0.03 %

References :

Textbook of Oral and Maxillofacial Surgery – Neelima Anil Malik

Sturdevants - Art & Science of Operative Dentistry - Fourth edition

Medical problems in dentistry –

Shully and cowsan.