Guidelines for Infection Control in Dental Health-Care Settings2003

CDC. MMWR 2003;52(No. RR-17)http://www.cdc.gov/oralhealth/infectioncontrol/guidelines/index.htm

This slide set Guidelines for Infection Control in Dental Health-Care Settings-Core and accompanying speaker notes provide an overview of many of the basic principles of infection control that form the basis for the CDC Guidelines for Infection Control in Dental Health-Care Settings 2003.

This slide set can be used for education and training of infection control coordinators, educators, consultants, and dental staff (initial and periodic training) at all levels of education.

Infection Control in Dental Health-Care Settings: An Overview

Guidelines for Infection Control in Dental Health-Care Settings2003. MMWR 2003; Vol. 52, No. RR-17.BackgroundPersonnel Health ElementsBloodborne PathogensHand HygienePersonal Protective EquipmentLatex Hypersensitivity/Contact DermatitisSterilization and DisinfectionEnvironmental Infection ControlDental Unit WaterlinesSpecial ConsiderationsProgram Evaluation

CDC RecommendationsImprove effectiveness and impact of public health interventionsInform clinicians, public health practitioners, and the publicDeveloped by advisory committees, ad hoc groups, and CDC staffBased on a range of rationale, from systematic reviews to expert opinions

Background

Why Is Infection Control Important in Dentistry?Both patients and dental health care personnel (DHCP) can be exposed to pathogensContact with blood, oral and respiratory secretions, and contaminated equipment occursProper procedures can prevent transmission of infections among patients and DHCP

Modes of TransmissionDirect contact with blood or body fluidsIndirect contact with a contaminated instrument or surfaceContact of mucosa of the eyes, nose, or mouth with droplets or spatterInhalation of airborne microorganisms

Chain of InfectionPathogenSourceModeEntrySusceptible Host

Standard PrecautionsApply to all patientsIntegrate and expand Universal Precautions to include organisms spread by blood and also Body fluids, secretions, and excretions except sweat, whether or not they contain bloodNon-intact (broken) skinMucous membranes

Elements of Standard PrecautionsHandwashingUse of gloves, masks, eye protection, and gownsPatient care equipmentEnvironmental surfacesInjury prevention

Personnel Health Elements

Personnel Health Elements of an Infection Control Program

Education and trainingImmunizationsExposure prevention and postexposure managementMedical condition management and work-related illnesses and restrictionsHealth record maintenance

Bloodborne Pathogens

Preventing Transmission of Bloodborne PathogensAre transmissible in health care settingsCan produce chronic infectionAre often carried by persons unaware of their infection

Bloodborne viruses such as hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV)

Potential Routes of Transmission of Bloodborne PathogensPatientDHCPDHCPPatientPatientPatient

Factors Influencing Occupational Risk of Bloodborne Virus InfectionFrequency of infection among patientsRisk of transmission after a blood exposure (i.e., type of virus)Type and frequency of blood contact

Average Risk of Bloodborne Virus Transmission after Needlestick

Concentration of HBV in Body Fluids High Moderate Low/Not Detectable

Blood Semen Urine Serum Vaginal Fluid Feces Wound exudates Saliva Sweat Tears Breast Milk

Estimated Incidence of HBV Infections Among HCP and General Population, United States, 1985-1999Health Care PersonnelGeneral U.S. Population

Source: Cleveland et al., JADA 1996;127:1385-90. Personal communication ADA, Chakwan Siew, PhD, 2005.PercentHBV Infection Among U.S. DentistsYear

Hepatitis B Vaccine

Vaccinate all DHCP who are at risk of exposure to bloodProvide access to qualified health care professionals for administration and follow-up testingTest for anti-HBs 1 to 2 months after 3rd dose

Transmission of HBV from Infected DHCP to PatientsNine clusters of transmission from dentists and oral surgeons to patients, 19701987Eight dentists tested for HBeAg were positiveLack of documented transmissions since 1987 may reflect increased use of gloves and vaccineOne case of patient-to-patient transmission, 2003

Occupational Risk of HCV Transmission among HCPInefficiently transmitted by occupational exposuresThree reports of transmission from blood splash to the eye Report of simultaneous transmission of HIV and HCV after non-intact skin exposure

HCV Infection in Dental Health Care SettingsPrevalence of HCV infection among dentists similar to that of general population (~ 1%-2%) No reports of HCV transmission from infected DHCP to patients or from patient to patient Risk of HCV transmission appears very low

Transmission of HIV from Infected Dentists to PatientsOnly one documented case of HIV transmission from an infected dentist to patientsNo transmissions documented in the investigation of 63 HIV-infected HCP (including 33 dentists or dental students)

Health Care Workers with Documented and Possible Occupationally Acquired HIV/AIDS CDC Database as of December 2002* 3 dentists, 1 oral surgeon, 2 dental assistants

Risk Factors for HIV Transmission after Percutaneous Exposure to HIV-Infected Blood CDC Case-Control Study Deep injuryVisible blood on deviceNeedle placed in artery or veinTerminal illness in source patient

Source: Cardo, et al., N England J Medicine 1997;337:1485-90.

Characteristics of Percutaneous Injuries Among DHCPReported frequency among general dentists has declinedCaused by burs, syringe needles, other sharps Occur outside the patients mouthInvolve small amounts of bloodAmong oral surgeons, occur more frequently during fracture reductions and procedures involving wire

Exposure Prevention StrategiesEngineering controlsWork practice controlsAdministrative controls

Engineering ControlsIsolate or remove the hazard Examples:Sharps containerMedical devices with injury protection features (e.g., self-sheathing needles)

Work Practice Controls

Change the manner of performing tasks Examples include:Using instruments instead of fingers to retract or palpate tissue One-handed needle recapping

Administrative ControlsPolicies, procedures, and enforcement measuresPlacement in the hierarchy varies by the problem being addressedPlaced before engineering controls for airborne precautions (e.g., TB)

Post-exposure Management ProgramClear policies and proceduresEducation of dental health care personnel (DHCP) Rapid access toClinical carePost-exposure prophylaxis (PEP)Testing of source patients/HCP

Post-exposure ManagementWound managementExposure reportingAssessment of infection riskType and severity of exposureBloodborne status of source personSusceptibility of exposed person

Hand Hygiene

Why Is Hand Hygiene Important?Hands are the most common mode of pathogen transmissionReduce spread of antimicrobial resistancePrevent health care-associated infections

Hands Need to be Cleaned WhenVisibly dirtyAfter touching contaminated objects with bare handsBefore and after patient treatment (before glove placement and after glove removal)

Hand Hygiene Definitions

HandwashingWashing hands with plain soap and waterAntiseptic handwashWashing hands with water and soap or other detergents containing an antiseptic agentAlcohol-based handrubRubbing hands with an alcohol-containing preparationSurgical antisepsisHandwashing with an antiseptic soap or an alcohol-based handrub before operations by surgical personnel

Efficacy of Hand Hygiene Preparations in Reduction of BacteriaGoodBetterBestPlain SoapAntimicrobial soapAlcohol-based handrubSource: http://www.cdc.gov/handhygiene/materials.htm

Alcohol-based PreparationsRapid and effective antimicrobial actionImproved skin conditionMore accessible than sinksCannot be used if hands are visibly soiledStore away from high temperatures or flamesHand softeners and glove powders may build-up

BenefitsLimitations

Special Hand Hygiene ConsiderationsUse hand lotions to prevent skin dryness Consider compatibility of hand care products with gloves (e.g., mineral oils and petroleum bases may cause early glove failure)Keep fingernails shortAvoid artificial nails Avoid hand jewelry that may tear gloves

Personal Protective Equipment

Personal Protective EquipmentA major component of Standard PrecautionsProtects the skin and mucous membranes from exposure to infectious materials in spray or spatter Should be removed when leaving treatment areas

Masks, Protective Eyewear, Face ShieldsWear a surgical mask and either eye protection with solid side shields or a face shield to protect mucous membranes of the eyes, nose, and mouthChange masks between patientsClean reusable face protection between patients; if visibly soiled, clean and disinfect

Protective ClothingWear gowns, lab coats, or uniforms that cover skin and personal clothing likely to become soiled with blood, saliva, or infectious material

Change if visibly soiled

Remove all barriers before leaving the work area

GlovesMinimize the risk of health care personnel acquiring infections from patientsPrevent microbial flora from being transmitted from health care personnel to patientsReduce contamination of the hands of health care personnel by microbial flora that can be transmitted from one patient to anotherAre not a substitute for handwashing!

Recommendations for GlovingWear gloves when contact with blood, saliva, and mucous membranes is possibleRemove gloves after patient care Wear a new pair of gloves for each patient

Recommendations for Gloving

Remove gloves that are torn, cut or puncturedDo not wash, disinfect or sterilize gloves for reuse

Latex Hypersensitivity and Contact Dermatitis

Latex AllergyType I hypersensitivity to natural rubber latex proteinsReactions may include nose, eye, and skin reactionsMore serious reactions may include respiratory distressrarely shock or death

Contact DermatitisIrritant contact dermatitisNot an allergyDry, itchy, irritated areasAllergic contact dermatitis Type IV delayed hypersensitivityMay result from allergy to chemicals used in glove manufacturing

General RecommendationsContact Dermatitis and Latex AllergyEducate DHCP about reactions associated with frequent hand hygiene and glove use Get a medical diagnosisScreen patients for latex allergyEnsure a latex-safe environmentHave latex-free kits available (dental and emergency)

Sterilization and Disinfection of Patient Care Items

Critical InstrumentsPenetrate mucous membranes or contact bone, the bloodstream, or other normally sterile tissues (of the mouth)Heat sterilize between uses or use sterile single-use, disposable devicesExamples include surgical instruments, scalpel blades, periodontal scalers, and surgical dental burs

Semi-critical InstrumentsContact mucous membranes but do not penetrate soft tissue Heat sterilize or high-level disinfect Examples: Dental mouth mirrors, amalgam condensers, and dental handpieces

Noncritical Instruments and DevicesContact intact skinClean and disinfect using a low to intermediate level disinfectantExamples: X-ray heads, facebows, pulse oximeter, blood pressure cuff

Instrument Processing AreaUse a designated processing area to control quality and ensure safetyDivide processing area into work areas Receiving, cleaning, and decontamination Preparation and packaging Sterilization Storage

Automated Cleaning Ultrasonic cleanerInstrument washerWasher-disinfector

Manual CleaningSoak until ready to cleanWear heavy-duty utility gloves, mask, eyewear, and protective clothing

Preparation and PackagingCritical and semi-critical items that will be stored should be wrapped or placed in containers before heat sterilizationHinged instruments opened and unlockedPlace a chemical indicator inside the packWear heavy-duty, puncture-resistant utility gloves

Heat-Based SterilizationSteam under pressure (autoclaving)Gravity displacementPre-vacuum Dry heatUnsaturated chemical vapor

Liquid Chemical Sterilant/DisinfectantsOnly for heat-sensitive critical and semi-critical devicesPowerful, toxic chemicals raise safety concernsHeat tolerant or disposable alternatives are available

Sterilization Monitoring Types of IndicatorsMechanical Measure time, temperature, pressureChemical Change in color when physical parameter is reachedBiological (spore tests)Use biological spores to assess the sterilization process directly

Storage of Sterile and Clean Items and SuppliesUse date- or event-related shelf-life practicesExamine wrapped items carefully prior to useWhen packaging of sterile items is damaged, re-clean, re-wrap, and re-sterilizeStore clean items in dry, closed, or covered containment

Environmental Infection Control

Environmental SurfacesMay become contaminated Not directly involved in infectious disease transmissionDo not require as stringent decontamination procedures

Categories of Environmental Surfaces Clinical contact surfacesHigh potential for direct contamination from spray or spatter or by contact with DHCPs gloved hand Housekeeping surfacesDo not come into contact with patients or devicesLimited risk of disease transmission

Clinical Contact Surfaces

Housekeeping Surfaces

General Cleaning RecommendationsUse barrier precautions (e.g., heavy-duty utility gloves, masks, protective eyewear) when cleaning and disinfecting environmental surfacesPhysical removal of microorganisms by cleaning is as important as the disinfection processFollow manufacturers instructions for proper use of EPA-registered hospital disinfectantsDo not use sterilant/high-level disinfectants on environmental surfaces

Cleaning Clinical Contact SurfacesRisk of transmitting infections greater than for housekeeping surfacesSurface barriers can be used and changed between patients ORClean then disinfect using an EPA-registered low- (HIV/HBV claim) to intermediate-level (tuberculocidal claim) hospital disinfectant

Cleaning Housekeeping SurfacesRoutinely clean with soap and water or an EPA-registered detergent/hospital disinfectant routinelyClean mops and cloths and allow to dry thoroughly before re-usingPrepare fresh cleaning and disinfecting solutions daily and per manufacturer recommendations

Medical WasteMedical Waste: Not considered infectious, thus can be discarded in regular trashRegulated Medical Waste: Poses a potential risk of infection during handling and disposal

Regulated Medical Waste ManagementProperly labeled containment to prevent injuries and leakage Medical wastes are treated in accordance with state and local EPA regulations Processes for regulated waste include autoclaving and incineration

Dental Unit Waterlines, Biofilm, and Water Quality

Dental Unit Waterlines and BiofilmMicrobial biofilms form in small bore tubing of dental units Biofilms serve as a microbial reservoirPrimary source of microorganisms is municipal water supply

Dental Unit Water QualityUsing water of uncertain quality is inconsistent with infection control principlesColony counts in water from untreated systems can exceed 1,000,000 CFU/mL CFU=colony forming unitUntreated dental units cannot reliably produce water that meets drinking water standards

Dental Water QualityFor routine dental treatment, meet regulatory standards for drinking water.*

*

Available DUWL TechnologyIndependent reservoirsChemical treatmentFiltrationCombinationsSterile water delivery systems

Monitoring OptionsWater testing laboratoryIn-office testing with self-contained kitsFollow recommendations provided by the manufacturer of the dental unit or waterline treatment product for monitoring water quality

Sterile Irrigating Solutions

Use sterile saline or sterile water as a coolant/irrigator when performing surgical procedures

Use devices designed for the delivery of sterile irrigating fluids

Special ConsiderationsDental handpieces and other devices attached to air and waterlinesDental radiologyAseptic technique for parenteral medicationsSingle-use (disposable) DevicesPreprocedural mouth rinsesOral surgical procedures

Handling biopsy specimensHandling extracted teethLaser/electrosurgery plumes or surgical smokeDental laboratoryMycobacterium tuberculosisCreutzfeldt-Jacob Disease (CJD) and other prion-related diseases

Dental Handpieces and Other Devices Attached to Air and WaterlinesClean and heat sterilize intraoral devices that can be removed from air and waterlinesFollow manufacturers instructions for cleaning, lubrication, and sterilizationDo not use liquid germicides or ethylene oxide

Components of Devices Permanently Attached to Air and WaterlinesDo not enter patients mouth but may become contaminatedUse barriers and change between usesClean and intermediate-level disinfect the surface of devices if visibly contaminated

Saliva EjectorsPreviously suctioned fluids might be retracted into the patients mouth when a seal is createdDo not advise patients to close their lips tightly around the tip of the saliva ejector

Dental RadiologyWear gloves and other appropriate personal protective equipment as necessaryHeat sterilize heat-tolerant radiographic accessories Transport and handle exposed radiographs so that they will not become contaminatedAvoid contamination of developing equipment

Parenteral MedicationsDefinition: Medications that are injected into the bodyCases of disease transmission have been reportedHandle safely to prevent transmission of infections

Precautions for Parenteral MedicationsIV tubings, bags, connections, needles, and syringes are single-use, disposable Single dose vialsDo not administer to multiple patients even if the needle on the syringe is changedDo not combine leftover contents for later use

Single-Use (Disposable) DevicesIntended for use on one patient during a single procedureUsually not heat-tolerantCannot be reliably cleanedExamples: Syringe needles, prophylaxis cups, and plastic orthodontic brackets

Preprocedural Mouth RinsesAntimicrobial mouth rinses prior to a dental procedure Reduce number of microorganisms in aerosols/spatterDecrease the number of microorganisms introduced into the bloodstreamUnresolved issueno evidence that infections are prevented

Oral Surgical ProceduresPresent a risk for microorganisms to enter the bodyInvolve the incision, excision, or reflection of tissue that exposes normally sterile areas of the oral cavityExamples include biopsy, periodontal surgery, implant surgery, apical surgery, and surgical extractions of teeth

Precautions for Surgical ProceduresSterile Irrigating SolutionsSterile Surgeons GlovesSurgical Scrub

Handling Biopsy SpecimensPlace biopsy in sturdy, leakproof containerAvoid contaminating the outside of the containerLabel with a biohazard symbol

Extracted TeethConsidered regulated medical wasteDo not incinerate extracted teeth containing amalgamClean and disinfect before sending to lab for shade comparisonCan be given back to patient

Handling Extracted Teethin Educational SettingsRemove visible blood and debris Maintain hydrationAutoclave (teeth with no amalgam)Use Standard Precautions

Laser/Electrosurgery Plumes and Surgical SmokeDestruction of tissue creates smoke that may contain harmful by-productsInfectious materials (HSV, HPV) may contact mucous membranes of noseNo evidence of HIV/HBV transmissionNeed further studies

Dental LaboratoryDental prostheses, appliances, and items used in their making are potential sources of contaminationHandle in a manner that protects patients and DHCP from exposure to microorganisms

Dental LaboratoryClean and disinfect prostheses and impressions Wear appropriate PPE until disinfection has been completed Clean and heat sterilize heat-tolerant items used in the mouthCommunicate specific information about disinfection procedures

Transmission of Mycobacterium tuberculosisSpread by droplet nucleiImmune system usually prevents spreadBacteria can remain alive in the lungs for many years (latent TB infection)

Risk of TB Transmission in DentistryRisk in dental settings is lowOnly one documented case of transmission Tuberculin skin test conversions among DHP are rare

Preventing Transmission of TB in Dental SettingsAssess patients for history of TBDefer elective dental treatmentIf patient must be treated:DHCP should wear face maskSeparate patient from others/mask/tissueRefer to facility with proper TB infection control precautions

Creutzfeldt-Jakob Disease (CJD)and other Prion DiseasesA type of a fatal degenerative disease of central nervous system Caused by abnormal prion protein Human and animal formsLong incubation periodOne case per million population worldwide

New Variant CJD (vCJD)Variant CJD (vCJD) is the human version of Bovine Spongiform Encephalopathy (BSE) Case reports in the UK, Italy, France, Ireland, Hong Kong, CanadaOne case report in the United States former UK resident

Infection Control for Known CJD or vCJD Dental PatientsUse single-use disposable items and equipment Consider items difficult to clean (e.g., endodontic files, broaches) as single-use disposable Keep instruments moist until cleaned Clean and autoclave at 134C for 18 minutes Do not use flash sterilization

Program EvaluationSystematic way to improve (infection control) procedures so they are useful, feasible, ethical, and accurateDevelop standard operating proceduresEvaluate infection control practicesDocument adverse outcomesDocument work-related illnessesMonitor health care-associated infections

Infection Control Program GoalsProvide a safe working environmentReduce health care-associated infections Reduce occupational exposures

Program EvaluationStrategies and ToolsPeriodic observational assessmentsChecklists to document proceduresRoutine review of occupational exposures to bloodborne pathogens

Program evaluation provides an opportunity to identify and change inappropriate practices, thereby improving the effectiveness of your infection control program.

Additional slides for each section of the document will be developed and may be used in conjunction with the core slides. This presentation and supplemental slides may be broken into separate sections, depending on the trainees level of experience and knowledge, previous training, level of interest in specific topics, and the amount of time available.

The information in this slide set provides some of the available scientific rationale for performing infection control practices for which recommendations are made. These practices are broken into the broad categories listed on this slide.CDC develops a broad range of guidelines which are intended to improve the effectiveness and impact of public health interventions and inform key audiences, most often clinicians, public health practitioners, and the public.Guidelines can be developed by formal advisory committees, ad hoc work groups, and CDC staff. Development processes can vary, depending on topic, available scientific data, urgency, resources, etc. and are based on a range of rationale, depending on the availability of scientific evidence.This Guideline identifies infection control practices that CDC recommends for all settings where dental treatment is provided. Although CDC recommendations are not regulatory, some practices are mandated by federal, state, or local regulations. These are identified in the Recommendations Section of the CDC Guideline.During the provision of dental treatment, both patients and dental health care personnel (DHCP) can be exposed to pathogens through contact with blood, oral and respiratory secretions, and contaminated equipment.Following recommended infection control procedures can prevent transmission of infectious organisms among patients and dental health care personnel.

Dental patients and DHCP may be exposed to a variety of disease-causing microorganisms that are present in the mouth and respiratory tract. These organisms may be transmitted in dental settings through several routes, including:Intact or non-intact skin in direct contact with blood, oral fluids, or other potentially infectious patient materials.Indirect contact with a contaminated object (e.g., instruments, operatory equipment, or environmental surfaces).Contact of mucous membranes of the eyes, nose, or mouth with droplets (e.g., spatter) containing microorganisms generated (e.g., coughing, sneezing, talking) from an infected person and propelled a short distance.Inhalation of airborne microorganisms that can remain suspended in the air for long periods of time.Infection through any of these routes requires that all of the following conditions be present: An adequate number of pathogens, or disease-causing organisms, to cause disease.A reservoir or source that allows the pathogen to survive and multiply (e.g., blood).A mode of transmission from the source to the host.An entrance through which the pathogen may enter the host.A susceptible host (i.e., one who is not immune). The occurrence of all these events is considered the chain of infection. Effective infection control strategies prevent disease transmission by interrupting one or more links in the chain of infection.Previous CDC recommendations on infection control for dentistry (1986, 1993) focused on the use of Universal Precautions to prevent transmission of bloodborne pathogens. Universal Precautions were based on the concept that all blood and certain body fluids should be treated as infectious because it is impossible to know who may be carrying a bloodborne virus. Thus, Universal Precautions should apply to all patients. The relevance of Universal Precautions applied to other potentially infectious materials was recognized, and in 1996, CDC replaced Universal Precautions with Standard Precautions. Standard Precautions integrate and expand Universal Precautions to include organisms spread by:Blood.All body fluids, secretions, and excretions except sweat, regardless of whether they contain blood.Non-intact skin.Mucous membranes.Saliva has always been considered a potentially infectious material in dental infection control; thus, no operational difference exists in clinical dental practice between Universal Precautions and Standard Precautions.

Standard Precautions include:Handwashing.The use of personal protective equipment, such as gloves, masks, eye protection, and gowns, that are intended to prevent the exposure of skin and mucous membranes to blood and other potentially infectious materials.Proper cleaning and decontamination of patient care equipment.Cleaning and disinfection of environmental surfaces.Injury prevention through engineering controls or safer work practices.

Note: OSHA retains the use of the term Universal Precautions because they are concerned primarily with transmission of bloodborne pathogens.

Each dental office should have a written plan for an infection control program that includes elements to protect personnel. These elements include: Education programs for staff members. Immunization plan for vaccine preventable diseases. Exposure prevention and postexposure management, with follow-up of staff exposed to infectious organisms or potentially harmful materials. Medical condition management and work-related illnesses and restrictions. Maintenance of health records in accordance with all applicable state and federal laws.

Bloodborne viruses such as hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) are of concern to dental health care personnel (DHCP). These viruses: Can be transmitted to patients and health care personnel (HCP) in health care settings. Can produce chronic infection. Are often carried by persons unaware of their infection. Theoretically, transmission of bloodborne pathogens may occur from patient to DHCP, from DHCP to patient, and from patient to patient. Because DHCP frequently are exposed to blood and blood-contaminated saliva during dental procedures, they are at greater risk of infection by a bloodborne pathogen than are patients. The risk of infection with a bloodborne virus is largely determined by:Its prevalence, or frequency, in the patient population.The risk of transmission after an exposure to blood (risk varies by type of virus).The type and frequency of blood contacts. If health care personnel are frequently exposed to blood, especially if they are working with sharp objects such as needles, their risk of exposure to a bloodborne virus would be higher than if they rarely come into contact with blood.

This slide shows the average risk of transmission after a single needlestick from an infected patient by type of bloodborne virus. As shown here, risk varies greatly by type of virus. For instance, the risk of HBV transmission after a percutaneous exposure (e.g., needlestick) to HBV-infected blood varies from 1% 62%, depending on the hepatitis B e-antigen (HBeAg) status of the source patient. If the source patients blood is positive for HBeAg (a marker of increased infectivity), the risk of transmission can be as high as 62%. If the patients blood is hepatitis B surface antigen (HBsAg) positive but HBeAg negative, the risk varies from 1% 37%.The average risk of HCV transmission after a percutaneous exposure to HCV-infected blood is 1.8%. The average risk of HIV infection after a percutaneous exposure to HIV-infected blood is 0.3%. To put this in perspective, 1 in 3 needlesticks from an HBeAg+ source patient would result in infection compared to only 1 in 300 needlesticks from an HIV-infected patient. As mentioned earlier, one factor to consider in assessing the risk of infection is the type of body substances to which DHCP are exposed. This slide shows the concentration of HBV in various body fluids. On the left, in red, are the fluids with the highest concentration of virus. Moving from the left to the right side, the concentration decreases. Blood, for instance, has a higher virus concentration than urine or sweat. Saliva alone, without blood, has a moderate concentration of virus.In the early to mid-1980s, health care personnel (HCP) had a much higher incidence (i.e., the number of new infections each year) of HBV infection than the general population. By the early 1990s, however, the incidence among health care personnel had dropped below that found in the general population. This decrease likely is the result of increased use of Universal Precautions and the hepatitis vaccine.Among U.S. dentists, evidence of past HBV infection decreased from prevaccine levels of 14% in 1972 to ~9% in 1989. Since then, levels have remained relatively unchanged. This is because the prevalence (proportion) of HBV infection among all dentists should gradually decrease as older dentists (who are more likely to be infected and unvaccinated than younger dentists) retire.Both Occupational Safety & Health Administration (OSHA) regulations and CDC recommendations state that hepatitis B vaccine should be made available to all DHCP who are exposed to blood or other potentially infectious materials.Employers should provide easy access to a qualified health care professional who can administer the vaccine and provide appropriate follow-up testing. Post-vaccination testing for antibody to hepatitis B surface antigen (anti-HBs) response is indicated for DHCP who have blood or patient contact and are at ongoing risk for injuries with sharp instruments or needlesticks. Post-vaccination testing should be completed one to two months after the 3rd vaccine dose. Knowledge of antibody response should guide appropriate postexposure prophylaxis.

Since the early 1970s, nine clusters involving more than 300 cases of HBV transmission from infected DHCP to patients have been reported. Eight (8) providers tested for hepatitis B e-antigen were positive. Since 1987, however, no cases of DHCP-to-patient transmission of HBV have been reported, probably the result of increased use of Universal or Standard Precautions and increased use of the hepatitis B vaccine.In 2003, the first and only case of patient-to-patient transmission of HBV in a dental office was reported. A later investigation of office procedures indicated that proper infection control precautions were being followed and the exact mechanism of transmission could not be identified.HCV appears not to be efficiently transmitted through occupational exposures. Transmission of HCV generally has been associated with hollow-bore needles and not other sharp instruments. Although studies have not documented transmission associated with mucous membrane or non-intact skin exposure, at least two cases of transmission of HCV from a blood splash to the conjunctiva of the eye have been reported. In 2003, there was a report of simultaneous transmission of HIV and HCV from a nursing home patient to a health care worker. This transmission is thought to have occurred through a non-intact skin exposure. The investigation concluded that consistent use of barrier precautions might have prevented this transmission.

Currently, there is little information from which to estimate the occupational risk of HCV infection in dentistry. However, most studies suggest that the prevalence (frequency) of HCV infection among dentists, surgeons, and hospital-based HCP is ~1%2%, similar to that among the general population. There have been no reports of an HCV transmission from an infected DHCP to a patient or of patient-to-patient transmission of HCV in a dental health care setting.Based on this information, the risk of HCV transmission in dentistry appears very low.

To date, transmission of HIV from infected HCP to patients has been documented in only one practice. Investigation of the patients of a Florida dentist with AIDS strongly suggested that HIV was transmitted during dental care to 6 of approximately 1,100 patients tested.Additional evidence supporting the very small risk of HIV transmission to patients comes from investigations conducted in the early 1990s of patients of other HIV-infected HCP. Test results of more than 22,000 patients of 63 HIV-infected HCP, including 33 dentists or dental students, failed to identify any additional cases of transmission. As of December 2002, there were no DHCP among the 57 U.S. HCP with documented HIV transmission following a specific exposure to a known HIV-infected source. CDC also has received reports of 139 other HCP considered to have possible occupational HIV transmission; of these, only 6 were DHCP. For each of the 139 persons, no other risk for infection could be identified during follow-up investigation.

* Each of the 6 DHCP reported a history of occupational percutaneous or mucous membrane exposure to blood or body fluids in the dental setting, but HIV transmission could not be linked to a specific exposure. Several factors affect the risk of HIV transmission after an occupational exposure. In a study of health care personnel who had percutaneous exposure to HIV-infected blood, an increased risk for HIV infection was associated with exposure to a relatively large quantity of blood as indicated by deep injury, visible blood on the device, or a procedure involving a needle placed in an artery or vein. The risk was also increased if the exposure was to blood from patients with terminal illness, possibly reflecting the higher titer of HIV in late-stage AIDS. Available information indicates that percutaneous injuries among dentists declined from an average rate of 11 injuries per year in 1987 to