12: Infection control

Chapter 12 Infection control

Infection control

The term infection control is defined as all the processes and precautions that can be taken to control the spread of infection. The type of processes and precautions that are used in infection control are described as high, medium or low level. The classification of infection control procedures are based on the risk of transmission of the diseases that are being encountered and the procedures being done. High level infection control is where a patient is isolated from all contact with professional or family members and every procedure is done with appropriate barriers in place. High level disinfection is employed when patients contract highly infectious disease such as the haemorrhagic fevers which if transmitted are fatal. Medium level infection control is where barrier protection is used, but the risk of contracting the disease is not high but still possible. Low level infection control measures are used where the risk of transmission is low and only normal cleanliness is required.

There are problems in categorizing which level of infection control is appropriate for dentistry. Many of the patients who attend dental surgeries may asymptomatically carry potentially infectious diseases but they do not know they are infected (e.g. hepatitis B or C). The risk of transmission could be high in dentistry if there is blood to blood contact through, for example, an inoculation (sharps) injury. In addition, the major fluids encountered in dentistry are blood and saliva and these could potentially transmit infectious disease. The risk for most of the surgical procedures done in dentistry, therefore, is in the medium category. Since most dental patients who asymptomatically carry disease are unaware of their infectious status it is wise to treat everyone with the same precautions; these are often described as Standard or Universal Precautions.

Which infectious diseases are transmitted by dentistry?

The number of proven cases of infectious diseases that have been transmitted by dental personnel, treatment or patients is very limited and the diseases are listed in Table 12.1. The pathogens include Mycobacterium tuberculosis (the causative organism of the majority of cases of tuberculosis in humans), methicillin resistant Staphylococcus aureus (MRSA), Pseudomonas spp., and the hand, foot and mouth virus (Ch. 10), and their transmission has resulted in serious, but not life-threatening infections. The list also includes infections caused by Legionella spp. and hepatitis B virus which have resulted in death of dental personnel. The most infectious agent that is constantly present in the oral cavity of at least 30% of the population is herpes simplex type 1 (Ch. 10). This virus has not caused death, but it has been responsible for blindness, usually in dental personnel who do not wear protective spectacles. Some authors have reviewed the low number of transmissions of infection in dentistry and have questioned whether many of the precautions used are necessary or justified, based on a risk assessment. Whether infection control measures in dentistry are necessary cannot now be answered as it would be impossible to revert to anything but standard precautions. Public pressure and ethical responsibility would prevent any diminution in the standard of precautions or to test a reduced level of protection. In addition, most regulatory authorities now demand standard precautions are taken in dentistry and have used litigation to ensure that it is done.

Table 12.1 Proven cases of infection transmitted by dentistry.

Infectious agent Route of infection
HIV Use of infected instruments or direct injection of blood
Hepatitis B virus Sharps injury
Herpes simplex type 1 virus Contact of infected material with skin or eyes
Coxsackie viruses Contact with skin
Legionella spp Inhalation of contaminated dental unit water supplies
Pseudomonads (e.g. Pseudomonas aeruginosa) Contact with contaminated dental unit water supplies
MRSA (Methicillin resistant Staphylococcus aureus) Contact with skin
Mycobacterium tuberculosis Inhalation of infected droplets

Personal protection

Personal protection is an important part of infection control. Important elements of personal protection in dentistry are immunization, protection of hands, eye and face, protective clothing and management and avoidance of inoculation (sharps) injuries.


The protection of dental personnel by immunization before they engage in dental procedures is an important part of infection control. Nowadays, many regulatory authorities require that dentists, nurses, hygienists and therapists are not carrying any potentially infectious disease before they undertake or assist with any dental procedures. Freedom from infectious disease and satisfactory records of immunization should be a contractual prerequisite before dental personnel are employed. The vaccinations required are listed in Table 12.2 and many of these are done routinely in adolescence. The exception to this is hepatitis B vaccination which needs to be satisfactorily completed before any exposure to surgical procedures is done.

Table 12.2 Recommended vaccinations for all dental personnel.

Vaccine Route Length of protection
Diphtheria IM* Probably life-long
Hepatitis B IM At least 5 years but probably life-long
Pertussis (Whooping Cough) IM Probably life-long
Poliomyelitis IM Probably life-long
Rubella IM Probably life-long
Tetanus IM At least 10 years but probably life-long
Tuberculosis (BCG) IM Probably less than life-long in most recipients

* IM = intramuscular

Jan 5, 2015 | Posted by in General Dentistry | Comments Off on 12: Infection control
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