BY, SMIJAL

PSM DENTAL COLLEGE

CONTENTSINTRODUCTIONIMMUNITYCOMMON TRANSMISSIBLE INFECTIONS IN

DENTISTRYCATEGORIES OF TASK IN RELATION TO RISKVACCINES FOR DENTAL HEALTH CARE WORKERSPERSONAL BARRIER TECHNIQUES FOR INFECTION

CONTROLSTERILIZATION OR DISINFECTION OF INSTRUMENTSUSE OF EXTRACTED TEETH IN DENTAL

EDUCATIONAL SETTINGSCONCLUSIONBIBLIOGRAPHY

INTRODUCTION Infectious diseases have scourged the world throughout historyA set of infection-control strategies common to all health-care

delivery settings should reduce the risk of transmission of infectious diseases caused by bloodborne pothogens such as HBV and HIV

Because all infected patients cannot be identified by medical history, physical examination, or laboratory tests, Centers for Disease Control and prevention (CDC) recommends that blood and body fluid precautions be used consistently for all patients. These precautions, referred to as universal precautions,

Transmission of HBV from dentists to patients has not been reported since 1 987, possibly due to increased adherence to universal precautions - including routine glove use by dentists - and increased levels of immunity due to the use of hepatitis B vaccine

Epidemiologic and laboratory data indicate that these infections probably were transmitted from the dental health care workers (DHCWs) to patients, rather than from one patient to another.

IMMUNITYThe word immunity is derived from a Latin word

‘immuni-s’ meaning ‘free from’ or exempt’.Immunity, therefore is the condition which

renders the host non suceptible or resistant to infective processes caused by bacteria or their products.

Immunity is therefore classified into 2 main divisions. 1. Natural immunity 2. Acquired immunity

NATURAL IMMUNITYThis is an inherited resistance to infection

and not acquired during the lifetime of an individual. They include. • Phagocytosis of bacteria by WBC’s and cells of the tissue macrophage system. • Destruction by the acid secretions of the stomach. • Presence of certain chemical compounds in the blood likes lysozyme that destroys microorganisms.

ACQUIRED IMMUNITYThe immunity acquired during the lifetime of

an individual is known as acquired immunity. It may be,

The immunity acquired during the lifetime of an individual is known as acquired immunity. It may be, 1. ACTIVE IMMUNITY2. PASSIVE IMMUNITY

ACTIVE IMMUNITYAcquired by an individual in response to the

introduction of microorganism or their toxin into the body and the cells of the body take part in the formation of antibodies

Further divided into natural & artificialNatural active immunity is acquired after an

infectionArtificial active immunity is acquired

artificially by inoculation of bacteria, virus or their products

COMMON TRANSMISSIBLE INFECTIONS IN DENTISTRYThe dental environment is associated with a significant

risk of exposure to various microorganisms. Many infectious agents may present in blood or saliva,

as a consequence of bacteremia or viremia associated with systemic infections.

These microorganisms may include cytomegalovirus, hepatitis B virus (HBV), hepatitis C virus (HCV), herpes simplex virus types 1 and 2, human immunodeficiency virus (HIV), mycobacterium tuberculosis, staphylococci, streptococci, and other viruses and bacteria - specifically, those that infect the upper respiratory tract

HERPES VIRUS INFECTIONThe herpes viruses are ubiquitous and are

commonly present in the mouth. 50-90% of patients may be infected and may shed one or more of the viruses at different times. This shedding is particularly common for Epstein- Barr Virus (EBV) and Human Herpes Virus type 6 (HHV-6).

Routine use of universal precautions, usage of gloves and avoidance of direct contact with oral mucosal HSV ulcers provide adequate protection against HSV in dental care workers.

ACUTE VIRAL HEPATITISViral hepatitis is currently divided into five

primarytypes,A, B, C, D. E

HEPATITIS BThe hepatitis B virus was first described in 1 965. The infective particle consists of an inner core

plus an outer surface coat. The core contains DNA and DNA polymerase and

replicates in the infected liver cells. Hepatitis B surface antigen (HBs Ag) is found on

the surface of the virus. The first humoral response to HBV infection is

the development of gM antibody to HBVAg (Anti HBc).

It develops in all patients with HBV infection and persists indefinitely.

Anti- HBs is responsible for long-term immunity.

CLINICAL SIGNS & SYMPTOMS OF HEPATITIS BIt varies from a mild flu like illness to fulminant,

fatal liver failure depending on the individuals general health and immune response

The onset of acute disease is generally insidious.

The prodromal phase begins suddenly with anorexia, malaise, nausea, vomiting and fever. Urticaria and arthralgia may also occur.

After 3 to 10 days, dark urine appears followed by Jaundice.

After I to 2 weeks, Jaundice fades and recovery begins in 2 to 4 weeks

MODES OF TRANSMISSION IN DENTISTRYHBV is transmitted both percutaneously and non

percutaneouslyBecause dental treatment involves the use of

small, sharp, contaminated instruments transferred between dental care providers during treatment, multiple opportunities exist for inadvertent percutaneous wounds to the operator and staff

HBV transmission during dental procedures occurs primarily in a horizontal mode among staff and patients, predominantly from patient to care provider and less likely from care provider to patient.

TREATMENT OF HEPATITIS BEffective treatment is still not available. However, sub-cutaneous administration of

interferon alfa-2b was effective in inducing a sustained loss of viral replication.

PREVENTION OF TRANSMISSION OF HBVHepatitis B vaccine • Plasma - derived vaccine • Recombinant DNAvaccine

PLASMA DERIVED VACCINE. The vaccine is given in 3 separate 20 mg

intramuscular injections; the first two doses 1 month apart and the third dose at 6 months (0,1,6).

RECOMBINANT DNA VACCINEIt provided an alternative to the plasma derived

vaccine.Administered vaccine is designed to contain 10

mg of HBs Ag proteinThe regimen is same as that of the plasma

derived vaccineHowever it has been shown to induce protective

anti-HBs in more than 99% of healthy adultsModifications have resulted in superior forms of

the Recombivax HB vaccine

PASSIVE IMMUNIZATIONIt is usually required after accidental

needlestick injuries during treatment of patients.

A single injection of hyper immunoglobulin, given within 48 hours after injury, usually reduces the severity of infection.

Simultaneously active immunization should also be provided.

HIV INFECTIONHuman immuno deficiency virus (HIV) is a member of

the retro virus family that can lead to Acquired Immuno Deficiency Syndrome (AIDS)

A condition in which the immune system begins to fail leading to life threatening opportunistic infections

Transmission occurs through contact with blood and other body fluids

In the early stages, the HIV infection may not be noticeable and may be accompanied by symptoms such as weakness, arthralgias, or even be totally asymptomatic

On progression, HIV infection may be associated with a variety of conditions

Some of the oral lesions associated with HIV infection and AIDS are Hairy Leukoplakia, Kapasis Sarcoma and Candidiasis

CLINICAL MANIFESTATION OF AIDS Unexplained diarrhea lasting longer than 1 month. Fatigue Malaise Loss of more than 10%bodyweight. Fever Night sweats Oralthrush Generalized Iymphadenopathy Enlarged spleen Opportunistic infections like,

Pneumocystis carinii pneumonia Encephalitis Meningitis Cytomegalovirus rhinitis. Herpes simplex infections Tuberculosis

TUBERCULOSISTuberculosis is one of the oldest infectious diseases known

to humans.Mycobacterium tuberculosis is the organism which

commonly affects the lungs but may involve any organ in the body

TB mimics many respiratory conditions, therefore when the practitioner observes a cough of more than 3 weeks of duration, sputum possibly tinged with blood, unexplained weight loss, and night sweats, the patient should be referred for a TB skin test and treatment

If diagnosed with active infection the patient must be treated till pronounced non-infectious and then may access dental care

Extra facilities are required for treating TB patientsFacilities should include negative air pressure treatment

rooms with the air vented to the outside of the building

ROUTES OF TRANSMISSIONInfections may be transmitted in the dental

operatory through several routes, including direct contact with blood, oral fluids, or other secretions

Indirect contact with contaminated instruments, operatory equipment, or environmental surfaces

Infection via any of these routes requires that all three of the following conditions be present (commonly referred to as “the chain of infection”): a susceptible host; a pathogen with sufficient infectivity and numbers to cause infection; and a portal through which the pathogen may enter the host

CATEGORIES OF TASK IN RELATION TO RISKCategory I:Tasks that involve exposure to blood, body fluid or tissues. Most tasks performed by the dentist, dental hygienist, dental assistant and laboratory technician falls in this category.Category II:Tasks that do not involve routine exposure to blood, body fluids or tissues. However, unplanned category tasks may occasionally be required. Clerical or non-professional workers who may help clean up the office, handle instruments or impression materials or send dental materials to the laboratory fit into this category.

Category Ill:Tasks that involve no exposure to blood, body fluids or tissues. A front-office receptionist, book keeper or insurance clerk who does not handle dental instruments or materials would be a category Ill worker.

VACCINES FOR DENTAL HEALTH CARE WORKERSThe OSHA bloodborne pathogens final rule

requires that employers make hepatitis B vaccinations available without cost to their employees who may be exposed to blood or other infectious materials.

CDC recommends that all workers, including DHCWs, who might be exposed to blood or blood-contaminated substances in an occupational setting be vaccinated for HBV

PERSONAL BARRIER TECHNIQUES FOR INFECTION CONTROL1. Washing and care of the hands DHCWs should wash their hands before and

after treating each patient and after barehanded touching of inanimate objects likely to be contaminated by blood, saliva, or respiratory secretions.

Hands should be washed after removal of gloves because gloves may become perforated during use and DHCWs’ hands may become contaminated through contact with patient material

2. GlovesFor protection of personnel and patients in dental-care settings, medical gloves (latex or vinyl) always must be worn by DHCWs when there is potential for contacting blood, blood- contaminated saliva, or mucous membranes.Non-sterile gloves are appropriate for examinations and other nonsurgical proceduressterile gloves should be used for surgical procedures.Washing of gloves may cause “wicking” (penetration of liquids through undetected holes in the gloves) and is not recommended

3. GownsProtective clothing such as reusable or disposable gowns, laboratory coats, or uniforms should be worn when clothing is likely to be soiled with blood or other body fluids. Reusable protective clothing should be washed using a normal laundry cycle, according to the instructions of detergent and machine manufacturersProtective clothing should be changed at least daily or as soon as it becomes visibly soiled

4. Masks / Protective eye wearChin-length plastic face shields or surgical masks and protective eyewear should be worn when splashing or spattering of blood or other body fluids is likely, as is common in dentistry. When a mask is used, it should be changed between patients or during patient treatment if it becomes wet or moist5. Rubber damAppropriate use of rubber dams, high- velocity air evacuation, and proper patient positioning should minimize the formation of droplets, spatter, and aerosols during patient treatment.

USE & CARE OF SHARP INSTRUMENTS & NEEDLESSharp items (e.g., needles, scalpel blades, wires)

contaminated with patient blood and saliva should be considered as potentially infective and handled with care to prevent injuries

Used needles should never be recapped or otherwise manipulated utilizing both hands, or any other technique that involves directing the point of a needle toward any part of the body

Either a one- handed ‘scoop technique or a mechanical device designed for holding the needle sheath should be employed

STERILIZATION OR DISINFECTION OF INSTRUMENTSSterilization describes a process that

destroys or eliminates all forms of microbial life and is carried out in health-care facilities by physical or chemical methods.

When chemicals are used to destroy all forms of microbiologic life, they can be called chemical sterilants

Disinfection describes a process that eliminates many or all pathogenic microorganisms, except bacterial spores, on inanimate objects.

In health-care settings, objects usually are disinfected by liquid chemicals or wet pasteurization.

Each of the various factors that affect the efficacy of disinfection can nullify or limit the efficacy of the process

CLEANINGCleaning is the removal of visible soil (e.g.,

organic and inorganic material) from objects and surfaces and normally is accomplished manually or mechanically using water with detergents or enzymatic products

Thorough cleaning is essential before high-level disinfection and sterilization because inorganic and organic materials that remain on the surfaces of instruments interfere with the effectiveness of these processes

As with other medical and surgical instruments, dental instruments are classified

A. Critical: Surgical and other instruments used to penetrate soft tissue or bone are classified as critical and should be sterilized after each use. These devices include forceps, scalpels, bone chisels, scalers and burs.

B.Semi critical: Instruments such as mirrors and amalgam condensers that do not penetrate soft tissues or bone but contact oral tissues are classified as semicritical. These devices should be sterilized after each use.

C.Noncritical: Instruments or medical devices such as external components of xray heads that come into contact only with intact skin are classified as noncritical. Because these noncritical surfaces have a relatively low risk of transmitting infection, they may be reprocessed between patients with intermediate-level or low- level disinfection or detergent and water washing, depending on the nature of the surface and the degree and nature of the contamination.

The three most commonly used methods of sterilization in dentistry are:

1.The steam autoclave2.The unsaturated chemical vapour sterilizer

(Chemiclave)3.DryheatovensOther methods are: Exposure to ethylene oxide gas Boiling water Ionizing radiation

AUTOCLAVEIt is an efficient, reliable and rapid method of

sterilization except for oils, greases and powders.

All living organisms are rapidly destroyed at l2l °C temperature and 15 lbs. pressure for 1 5 minutes.

The major problems are excess moisture, air entrapment and severe wetting

DRY HEAT STERILIZERThese sterilizers use hot air to kill

microorganisms and do not cause corrosion. The standard dry heat sterilizing oven

operates at an air temperature of about 320 F for exposure times of 60-120 minutes.

Closed containers can be used.

CLEANING & DISINFECTION OF DENTAL UNIT & ENVIRONMENTAL SURFACESImpervious-backed paper, aluminum foil, or plastic

covers should be used to protect items and surfaces (e.g., light handles or x-ray unit heads) that may become contaminated by blood or saliva during use and that are difficult or impossible to clean and disinfect.

Between patients, the coverings should be removed (while DHCWs are gloved), discarded and replaced (after ungloving and washing of hands) with clean material.

After treatment of each patient and at the completion of daily work activities, countertops and dental unit surfaces that may have become contaminated with patient material should be cleaned with disposable toweling, using an appropriate cleaning agent and water as necessary.

Surfaces then should be disinfected with a suitable chemical germicide.

A chemical germicide classified as a “hospital disinfectant’ and labeled for ‘tuberculocidal” (i.e, mycobactericidal) activity is recommended for disinfecting surfaces that have been soiled with patient material.

These intermediate-level disinfectants include phenolics, lodophors, and chlorine- containing compounds

DISINFECTION AND THE DENTAL LABORATORYLaboratory materials and other items that have been

used in the mouth (e.g., impressions, bite registrations, fixed and removable prostheses, orthodontic appliances) should be cleaned and disinfected before being manipulated in the laboratory.

These items also should be cleaned and disinfected after being manipulated in the dental laboratory and before placement in the patient’s mouth.

A chemical germicide having at least an intermediate level of activity (i.e., “tuberculocidal h6spital disinfectant’) is appropriate for such disinfection.

1. Receiving area: A receiving area should be established separate from the

production area. Countertops and work surfaces should be cleaned and then

disinfected daily with an appropriate surface disinfectant used according to the manufacturers directions.

2. Incoming cases: Unless the laboratory employee knows that the case has been

disinfected by the dental office, all cases should be disinfected as they are received.

Containers should be sterilized or disinfected after each use. Packing materials should be discarded to avoid cross

contamination.3. Production area: Persons working in the production area should wear a clean

uniform or laboratory coat, a face mask, protective eyewear and disposable gloves.

Work surfaces and equipment should be kept free of debris and disinfected daily.

Any instruments, attachments and materials to be used with new prostheses or appliances should be maintained separately from those to be used with prostheses or appliances that have already been inserted in the mouth. Brushes and other equipment should be disinfected at least daily.

HANDLING OF BIOPSY SPECIMENSIn general, each biopsy specimen should be

put in a sturdy container with a secure lid to prevent leaking during transport.

Care should be taken when collecting specimens to avoid contamination of the outside of the container.

If the outside of the container is visibly contaminated, it should be cleaned and disinfected or placed in an impervious bag.

USE OF EXTRACTED TEETH IN DENTAL EDUCATIONAL SETTINGSExtracted teeth used for education should be considered

infective and classified as clinical specimen because they contain blood.

All persons who collect, transport, or manipulate extracted teeth should handle them with the same precautions as a specimen for biopsy.

Universal precautions should be adhered to whenever extracted teeth are handled, because preclinical educational exercises simulate clinical experiences and the students enrolled in dental educational programs should adhere to universal precautions in both preclinical and clinical settings.

In addition, all persons who handle extracted teeth in dental preclinical settings should receive hepatitis B vaccine.

CONCLUSIONThe aim of infection control is to control iatrogenic,

nosocomial infections among patients, and potential occupational exposure of care providers to disease causing microbes during provision of care.

Disease transfer to the dentist and dental staff during dental care is considered an “occupational exposure” to a given pathogen while disease transfer from one patient to another in the dental clinics is considered “cross-infection”.

Therefore, the dental health care provider must be knowledgeable about the diseases commonly encountered in the dental operatory and must follow high standards of infection control for the safety of the patients and the dental health care workers.

BIBLIOGRAPHYPreventive and community dentistry- Soben

Peter 4th editionPreventive and community dentistry- Joseph

johnTextbook of public health and dentistry by

Marya Textbook Of Preventive And Community

Dentistry by Hiremath