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1 CPD Cre Tpic 1 Hur Verified Read this article and answer the 10 questins belw fr 1 hur f Cre Tpic CPD. If yu'd like t have this CPD verified, please register fr free at and answer the questins nline. Once yu've cmpleted the test, yur certificate will be added t yur accunt autmatically and yur egdc accunt will be updated. Yur CPD - Hassle Free. Disinfectin and Decntaminatin Infectin Cntrl Aersls and Splatter as an Occupatinal Hazard in Dentistry Objectives After reading this paper, the yu shuld understand: The presence and make up f dental aersls and splatter. The threats that may be inherent in airbrne material, including the risk ptential t patients and the dental team. Regulatry and legal cncerns regarding infectin cntrl. Cntents Overview Dental Aersl and Splatter Cmpsitin f Dental Aersls Surces f Airbrne Cntaminatin During Dental Treatment 1) Bld 2) Saliva and respiratry surces 3) Dental instrumentatin 4) The perative site Cmpsitin f Dental Aersls Methds f Reducing Airbrne Cntaminatin/Expsure t Dental Aersl Regulatry and Legal Cncerns Cnclusins Questins References Overview

2 Airbrne material is prduced during all prcedures perfrmed with the use f dental hand-pieces. This airbrne material includes aersl and splatter, which is usually cntaminated with fungi, viruses, bacteria and ften bld. Dentists, auxiliary staff and patients are all affected by this airbrne material. An aersl, which is a clud f particulate matter and fluid, can be seen during the use f an ultrasnic scaler, during tth preparatin with a rtary instrument r air abrasin, during the use f an air-water syringe, r during air plishing. Aersl prduced frm dental hand-pieces is a mixture f air cming frm the hand-piece, water frm dental unit waterlines (DUWL) and the patient s saliva. Aersl is almst always accmpanied by splatter. The principal difference between the tw is the size f the particle frm which they are made. This airbrne material has the ptential fr transmissin f diseases and varius infectins t the practitiners and patients, and has becme a surce f increased cncern t the dental prfessin. This article reviews relevant literature n the presence and makeup f dental aersls and splatter. This article assesses the threats caused by this airbrne material, including the risk ptential t patients and the dental team. It als fcuses n the cntrl f dental aersls and splatter. Dental Aersl and Splatter Aersls are defined as liquid r slid particles less than 50 µm in diameter. Particles f this size are small enugh t remain suspended in air fr a lng perid befre they settle n envirnmental surfaces r enter the respiratry tract. They may be easily inhaled by dental staff r patients. Smaller particles f aersl are mre infectius, in terms f bth the degree f infectivity and the severity f illness that can result. Aersl particles that are 0.5 t 10 µm in diameter are capable f penetrating and ldging deep int the lungs, reaching as far as pulmnary alveli, and are thught t carry the greatest ptential fr transmitting infectins. Splatter is defined as airbrne particles larger than 50 µm in diameter and is smetimes visible t the naked eye. Splatter is a mixture f air, water and/r slid substances, such as fragments f carius tissues, dental fillings and sandblasting pwder. Splatter particles mve ballistically; i.e. they are ejected frcibly frm the perating site, mve alng the trajectries and settle quickly n an bject. Splatter particles can cme int cntact with the skin, eyes, mucsa f the nse and the pen muth. Being larger in size, these particles are nly briefly airbrne, and they have limited ptential t penetrate int the respiratry system. The greatest threat in dentistry cmes frm airbrne infectin thrugh aersls (<50 µm in diameter) due t the aersl particles ability t stay lnger in the air and their ptential t enter respiratry passages. Hwever, with the resurgence f tuberculsis (TB), splatter drplets must als be cnsidered a ptential infectin threat. Splatter and drplet infectin are als invlved in the transmissin f varius diseases ther than TB, such as SARS, measles and herpetic viruses. Sme f the

3 diseases knwn t be spread thrugh an airbrne rute are listed in the table belw. Diseases knwn t be spread by drplets r aersls: Disease Measles Influenza Severe Acute Respiratry Syndrme Leginnaires Disease Tuberculsis Methd f Transmissin Spread easily frm persn t persn, when drplets f viruses are circulated thrugh the air frm an infected persn sneezing r cughing. Spread thrugh drplets caused by cughing r sneezing. May require direct cntact with the patient. One can get infected by tuching the surface r bject that was recently cntaminated by the virus and then tuching ne s nse r muth. Spread by clse cntact with infected persn and aerslised drplets. Des nt spread frm persn t persn cntact. Aerslisatin f Leginella pneumphilia has been assciated with air cnditining systems, evaprative cndensers and ht tub spas. Transmissin f tubercle bacilli ccurs thrugh the inhalatin f drplet nuclei f expectrated sputum-psitive tuberculsis patients during cughing and sneezing. TB was nce cnsidered t be an ccupatinal disease fr dentists. Cmpsitin f Dental Aersls Aersl cmpsitin varies with each patient, the perative site and the type f treatment prcedure (e.g. tth preparatin, scaling, r plishing) in the ral cavity. Aersl may cnsist f saliva, naspharyngeal secretins, dental plaque, gum secretins, bld, tth cmpnents and any material used in the dental prcedure, such as abrasives fr air plishing and air abrasin. The micrbilgical cmpsitin f dental aersl depends n the micrflra present in the patient s ral cavity and the water frm dental unit waterlines (DUWL) attached t the hand-piece. They are usually cntaminated with bacteria, viruses and fungi. The types f bacterial genus present in aersl are Streptcccus, (cnstituting abut 42 per cent f ttal bacteria), Staphylcccus (41 per cent) and gram negative bacteria (17 per cent). A nn-selective grwth medium such as a bld agar has been cmmnly used t measure the number f airbrne bacteria. Studies shw that the micrflra f air in a dental surgery has the highest prevalence f Staphylcccus epidermidis (37.1 per cent f ttal bacteria), Micrcccus spp. (32.6 per cent), nndiphterial crynebacteria (28.2 per cent), Staphlycccus aureus (0.6 per cent) and fungi (0.9 per cent). Aersl prduced during cnservative treatment cnsists f bacteria f the genera Streptcccus mutans/ratti and Lactcccus lactis in numerus amunts.

4 Surces f Airbrne Cntaminatin During Dental Treatment Ptential surces f airbrne cntaminatin during dental treatment are: 1) Bld. 2) Saliva and respiratry surces. 3) Dental instrumentatin. 4) The perative site. 1) Bld The presence f bld (r its cmpnents) in dental aersl is an imprtant prblem. Dentists and their assistants are ften accidentally splashed with bld due t an incrrect wrking technique with dental unit handpieces, scalers, r during minr surgery. The greatest risks fr dentists are viruses spread thrugh bld (hepatitis B and C, HIV virus). These viruses cause life threatening diseases. The Hepatitis B virus cnstitutes an ccupatinal hazard t dentists as the disease is easily transmitted, highly infectius, and highly resistant t disinfectin, sterilisatin and envirnmental agents. Hepatitis C is als a serius health prblem as the infectin is asymptmatic and may develp int chrnic liver inflammatin and then int cirrhsis and liver cancer. 2) Saliva and respiratry surces The ral cavity is almst always wet with saliva that cntinuusly replenishes the fluid in the muth. The muth is part f the r-nasal pharynx. As part f this cmplex, the muth harburs bacteria and viruses frm the nse, thrat and respiratry tract. The fluids in the muth are grssly cntaminated with bacteria and viruses. Dental plaque, bth supra-gingival and sub-gingival, is a majr surce f these rganisms. Any dental prcedure that has the ptential t aerslise saliva will cause airbrne cntaminatin with rganisms frm sme r all f these surces. Saliva includes a vast range f micrrganisms. The Herpes simplex virus (HSV) and Mycbacterium tuberculsis (TB) are the mst imprtant risk factrs. HSV-1 and HSV-2 are particular hazards fr dental wrkers because f their cmmn ccurrence and high infectivity. They cause herpetic whitlw, recurrent labial herpes and keratitis. Mycbacterium develping in the pharynx f a TB patient can be emitted int the air during a prcedure, mst ften during cughing. This, tgether with dried saliva r sputum drplets (called drplet nuclei), can lead t ccupatinal TB fr dentists. Aersls prduced during treatment in an active TB patient can be cntrlled using special respiratry precautins. Patients with undiagnsed, active, infectius TB remain a risk fr the dental team and ther patients, hwever. Saliva and naspharyngeal secretins may als cntain ther pathgenic

5 rganisms. These include the herpes virus, influenza, cmmn cld viruses, pathgenic Streptccci and Staphylccci, and the SARS virus. During treatment, it shuld be assumed that all patients may have an infectius disease that can spread by dental aersls. Therefre, universal precautins t limit aersls shuld be taken. 3) Dental instrumentatin Unclean instruments and imprper sterilisatin can lead t the cntaminatin f dental instruments and dental unit waterlines (DUWLs). Rutine cleaning and sterilisatin prcedures shuld eliminate cntaminatin. The aersl prduced frm dental handpieces is a mixture f air cming frm a handpiece, water frm the patient s saliva and water flwing frm DUWLs, and is always accmpanied by splatter. The applicatin f American Dental Assciatin (ADA) recmmended methds t treat the DUWL shuld minimise r eliminate airbrne cntaminatin frm the DUWL. 4) Cntaminatin frm the perative site Mst dental prcedures that use mechanical instrumentatin prduce airbrne particles frm the site where the instrument is used. Multiple studies have been cnducted t determine which dental prcedure prduces the mst airbrne bacterial cntaminatin. Dental handpieces r drills, ultrasnic scalers, air and water syringing, air plishers and air abrasin units prduce the mst visible aersls. Each f these instruments remves material frm the perative site that becmes aerslised by the actin f the rtary instrument, ultrasnic vibratins, r the cmbined actin f water sprays and cmpressed air. The table belw lists the dental instruments and prcedures that prduce the greatest amunt f aersls. Dental devices and prcedures knwn t prduce airbrne cntaminatin Ultrasnic and Snic Scalers Air Plishing Air-Water Syringe Knwn t prduce the greatest amunt f aersl cntaminatin; use f a high-vlume evacuatr will reduce the airbrne cntaminatin by mre than 95 per cent. Bacterial cunts indicate that airbrne cntaminatin is nearly equal t that f ultrasnic scalers; available suctin devices will reduce airbrne cntaminatin by mre than 95 per cent. Bacterial cunts indicate that airbrne cntaminatin is nearly equal t that f ultrasnic scalers; high-vlume evacuatr will reduce airbrne bacteria by nearly 99 per cent. Tth Preparatin Minimal airbrne cntaminatin if a rubber dam is used.

6 with Air Turbine Handpiece Tth Preparatin with Air Abrasin Bacterial cntaminatin is unknwn; extensive cntaminatin with abrasive particles has been shwn. The sites shwing the highest micrbilgical cntaminatin due t aersl and splatter during cnservative treatment and scaling are (in decreasing rder): dentist s and assistant s masks, a unit lamp, surfaces clse t spittns, and mbile instrument-material tables. The micrbilgical cnditin f air in dental surgeries is cnsidered t be ne f the mst dangerus cntaminatin carriers in the wrking envirnment f a dentist. Mnitring and the remval f micrbilgical cntaminated air frm dental surgery rms may reduce the spread f infectin. Als, prly maintained ventilatin and air-cnditining systems are a ptential surce f fungal and ther micrrganisms, resulting in infectin, allergic cnditins and hypersensitivity. Other factrs such as temperature, humidity, dispersin f particles and particle size in the perative site may als influence the distributin and ptential infectivity f aersls. Methds f Reducing Airbrne Cntaminatin/Expsure t Dental Aersls Methds f cntrlling aersl and splatter are simple and inexpensive. Majr surces f ptentially cntaminated dental aersls can be cntrlled fllwing the American Dental Assciatin s recmmendatins fr sterilisatin f instruments and treatment f dental unit waterlines. The aersl created by the interactin f clant water and ultrasnic vibratins, r by cmpressed air and a rtary mtin is visible t patients and dental persnnel and can be easily cntrlled. Emissin f the cntaminated particles int the wrking space shuld be first reduced, and then cntaminated air shuld be eliminated befre it has left the space directly surrunding the treated area. Persnal prtective barriers such as surgical masks, safety glasses with lateral prtectin and glves are standard prtective measures and can decrease cntact with aersls and splatter. Hwever, aersls f less than 1µm can readily penetrate surgical masks. T reduce such aersls, industrial respiratrs have been fund t be mre effective. The ptential fr the spread f infectin thrugh an almst invisible aersl is als pssible. Such aersls must be recgnised and minimised r eliminated t the greatest extent feasible within a clinical situatin. The use f an antiseptic muthwash with lng lasting antimicrbial activity, such as chlrhexidine glucnate (0.01%), has been fund t be effective in reducing bacterial aersls. The use f such muthwashes prir t ultrasnic scaling has been fund t be very effective in reducing the aersl. Chlrhexidine is an effective and cmmnly used antiseptic fr free flating ral bacteria, but it has n influence n the bacteria present in bifilm such as established dental plaque, des nt penetrate sub-gingivally, and des nt affect bacteria and viruses harbured in the naspharynx. Pre-prcedural rinses reduce the extent f cntaminatin within dental aersls,

7 but they d nt really eliminate the infectius ptential f dental aersls. The use f a rubber dam during many dental prcedures will eliminate all cntaminatin arising frm saliva and bld. If a rubber dam can be used, the nly remaining surce f airbrne cntaminatin is frm the tth that is underging treatment. Unfrtunately, the use f a rubber dam is nt feasible in many prcedures, such as sub-gingival restratins, the final steps f crwn preparatin, peridntal surgery and rt planing. Tw methds are available t reduce airbrne cntaminatin arising frm the perative site. One methd invlves the use f devices that remve the cntaminated material frm the air f the treatment area after it has becme airbrne. The ther remves the airbrne cntaminatin befre it leaves the immediate area surrunding the perative site. The mst frequently mentined methds fr remving airbrne cntaminatin frm the air f the treatment rm are the use f high efficiency particulate air (HEPA) filters and the use f ultravilet, r UV, chambers in the ventilatin system. UV radiatin with the wavelength 254 nm shuld be used as this shws very high bactericidal, fungicidal and virucidal activity by the destructin f DNA chains and prtein denaturatin. Althugh the use f HEPA and air filters appears t reduce airbrne cntaminatin, the disadvantages f these methds include technical changes and high expenditure. The disadvantage f UV radiatin is that it takes a lng perid fr the air in the treatment rm t cycle thrugh the filter r UV treatment system. Cnsidering the practical issues and cst effectiveness, it is much easier t remve as much airbrne cntaminatin as pssible befre it escapes the immediate treatment site. The use f a high vlume evacuatr (HVE) has been shwn t reduce the cntaminatin arising frm the perative site by mre than 90 per cent. The usual HVE used in dentistry has a large pening (usually 8 mm r greater) and is attached t an evacuatin system that remves a large vlume f air (up t 100 cubic feet f air per minute). During restrative dentistry, the HVE will ften be used by an assistant wh is able t guide and aim the vacuum in a manner that eliminates r greatly reduces the visible water spray prduced during dental prcedures. The water in the dental unit used t cl handpieces has been shwn t frm a bifilm, which is the mst abundant surce f micrrganisms. The thickness f this bifilm layer equals 30-50µm. Therefre, the quality f water used in dental unit handpieces shuld meet the cnditins f ptable water. Chemical disinfectants such as hydrgen perxide are cnsidered t be the mst effective measure by which t remve bifilms. Further, rutine sterilisatin f handpieces eliminates patient t patient infectin, cntaminatin f waterlines with micrrganisms and tissue fragments. Regular cleaning, disinfectin and sterilisatin f the unit water reservir, using distilled water and the applicatin f chemicals t mnitr the micrbilgical quality f dental unit waterline water, assures the effective micrbilgical cntrl f water and safety f unit users. The psitin f a patient during dental treatment is als imprtant. Patients shuld be treated in a supine psitin, thus aviding the need fr the dentist t wrk in the breath way f a patient.

8 Immunisatin f dental persnnel against varius diseases such as hepatitis B, influenza, measles, rubella, chicken px and tuberculsis is strngly recmmended. It must be emphasised that n single apprach r device can cmpletely minimise the risk f infectin t dental persnnel and ther patients. The dental team shuld nt depend n a single precautinary strategy. In the reductin f dental aersls, the first layer f defence is persnal prtectin barriers such as masks, glves and safety glasses. The secnd layer f defence is the rutine use f an antiseptic pre-prcedural rinse with a muthwash such as chlrhexidine. The third layer f defence is the rutine use f an HVE either by an assistant r attached t the instrument being used. The first three layers f defence are fund rutinely in mst dental clinics, are inexpensive and can easily be made part f rutine infectin cntrl practices. The table belw lists the available methds f reducing aersls and splatter cntaminatin, as well as their relative effectiveness and csts. Methds f reducing airbrne cntaminatin Device Advantages Disadvantages Barrier Prtectin: Masks, Glves and Eye Prtectin Part f standard precautins ; inexpensive. Masks will nly filter ut per cent f aersls; subject t leakage if nt well-fitted; d nt prtect when mask is remved after the prcedure. Pre prcedural rinse with antiseptic muthwash (chlrhexidine) High-Vlume Evacuatr High-Efficiency Particulate Air Rm Filters & Ultravilet Treatment f Ventilatin System Reduces the bacterial cunt in the muth, saliva and air; inexpensive n a perpatient basis. Will reduce the number f bacteria in the air and remve mst f the material generated at the perative site such as bacteria, bld and viruses; inexpensive n a per-patient basis. Effective in reducing numbers f airbrne rganisms. Tends t be mst effective n free flating rganisms; it will nt affect bifilm rganisms such as plaque, sub gingival rganisms, bld frm the perative site r rganisms frm the naspharynx. When an assistant is nt available, it is necessary t use a high-vlume evacuatr attached t the instrument r a dry field device. Only effective nce the rganisms are already in the rm s air; mderate t expensive; may require engineering changes t the ventilatin system.

9 Regulatry and Legal Cncerns The American Dental Assciatin and Centers fr Disease Cntrl have recmmended that all bld-cntaminated aersls and splatter shuld be minimised. Occupatinal Safety and Health Administratin regulatins state that all prcedures invlving bld r ther ptentially infectius materials shall be perfrmed in such a manner as t minimise splashing, spraying, spattering, and generatin f drplets f the substances. The use f rubber dams and HVEs are cnsidered t be apprpriate wrk practices precautins that always shuld be fllwed during dental prcedures. By fllwing the simple and inexpensive recmmendatins fr cntrlling aersls and splatter utlined in this article, dental practitiners will be in cmpliance with these recmmendatins and will minimise any legal r regulatry risks that may exist. Cnclusins The aersls and splatter generated during dental prcedures have the ptential t spread infectin t dental persnnel and ther peple in the dental ffice. It is difficult t cmpletely eliminate the risk psed by dental aersls; hwever, it is pssible t minimise the risk with relatively simple and inexpensive precautins. The fllwing prcedures are apprpriate as universal precautins whenever an aersl is prduced: a) Persnal barrier prtectin. b) Pre prcedural rinse befre treatment. c) Rubber dam used whenever applicable. d) HVE used fr all prcedures. The use f these precautins will reduce the risk f an aerslised spread f infectin t a minimal level.

10 Questins 1) Which f the fllwing dental prcedures prduces aersl? a) Tth preparatin using a rtary instrument. b) Use f an air-water syringe. c) Scaling using an ultrasnic scaler and during air plishing. d) All f the abve. 2) The size f an aersl particle is: a) <50 µm in diameter. b) >50 µm in diameter. c) µm in diameter. d) µm in diameter. 3) Splatter is defined as: a) A waterbrne particle. b) A dust particle. c) Airbrne particles larger than 50 µm in diameter. d) Airbrne particles less than 50 µm in diameter. 4) The cmmn diseases knwn t be spread by aersls are: a) Tuberculsis. b) Influenza. c) Leginnaires Disease. d) All f the abve. 5) The highest percentage f bacterial genus present in aersl is: a) Streptcccus. b) Staphylcccus. c) Diplcccus. d) Micrcccus. 6) The greatest surce f aersl cntaminatin is which item f dental equipment? a) Air-water syringe. b) Tth preparatin with air turbine handpiece. c) Ultrasnic and snic scalers. d) All f the abve. 7) Persnal barrier prtectin cmprises: a) Surgical masks, glves and eye prtectin. b) A rubber dam. c) A high vlume evacuatr. d) All f the abve.

11 8) Dental prcedures fr which a rubber dam cannt be used fr preventing infectin is/are: a) Sub-gingival restratins. b) Rt planning and peridntal surgery. c) Final steps f crwn preparatin. d) All f the abve. 9) The mst frequently mentined methd f remving airbrne cntaminatin frm the air frm a practical and cst effective viewpint is/are: a) A high vlume evacuatr (HVE). b) Ultravilet chambers. c) High efficiency particulate air (HEPA) filters. d) Nne f the abve. 10) Universal precautins t be taken t cntrl aersl is/are: a) Use f persnal barrier prtectin. b) Use f pre prcedural rinse befre treatment. c) Use f rubber dam where applicable. d) All f the abve. If yu'd like t have this CPD verified, please register fr free at and answer the questins nline. Once yu've cmpleted the test, yur certificate will be added t yur accunt autmatically and yur egdc accunt will be updated. Yur CPD - Hassle Free.