5 Infection Control in Surgical Practice

8/3/2019 5 Infection Control in Surgical Practice

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Infection Control

in Surgical Practice

James R. Hupp

C H A P T E R

CHAPTER OUTLINE

COMMUNICABLE PATHOGENIC ORGANISMSBacteria

Upper Respiratory Tract FloraMaxillofacial Skin FloraNonmaxillofacial Flora

Viral Organisms

Hepatitis VirusesHuman Immunodeficiency Virus

Mycobacterial OrganismsASEPTIC TECHNIQUES AND UNIVERSAL PRECAUTIONS

TerminologyConcepts

Techniques of Instrument SterilizationSterilization with Heat

Gaseous SterilizationTechniques of Instrument Disinfection

Chemical DisinfectantsMaintenance of Sterility

Disposable MaterialsSurgical Field Maintenance

Operatory DisinfectionSurgical Staff Preparation

Hand and Arm PreparationClean TechniqueSterile Technique

Postsurgical AsepsisWounds ManagementSharps Management

t would be difficult for a person currently living inan industrialized society to have avoided beingexposed to modern concepts of personal and public

hygiene. Personal cleanliness and public sanitation have been ingrained in the culture of modern civilized soci-eties through parental and public education and are rein-forced by government regulations and media advertising.This awareness contrasts starkly with earlier centuries,when the importance of hygienic measures for the con-trol of infectious diseases was not widely appreciated. Themonumental work of Semmelweis, Koch, and Lister led toenlightenment about asepsis so that today the use ofaseptic techniques seems instinctive.

Despite on-going advancements in the area of infectioncontrol, health professionals must still learn and practice

techniques that limit the spread of contagions. This isespecially true for dentists performing surgery for two rea-sons: First, to perform surgery the dentist typically violates

an epithelial surface, the most important barrier againstinfection. Second, during most oral surgical procedures,the dentist, assistants, and equipment become contami-nated with the patient'sblood and saliva.

COMMUNICABLE PATHOGENIC ORGANISMS

Two of the most important pieces of knowledge in anyconflict are the identity of the enemy and the enemy'sstrengths and weaknesses. In the case of oral surgery, theopposition includes virulent bacteria, mycobacteria,fungi, and viruses. The opposition's strengths are the var-

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ious means that organisms use to prevent their owndestruction, and their weaknesses are their susceptibilitiesto chemical, biologic, and physical agents. By under-standing the "enemy," the dentist can make rational deci-sions about infection control.

Bacteria

Upper respiratory tract flora. Normal oral flora con-tains the microorganisms usually present in the salivaand on the surfaces of oral tissues in healthy, immuno-competent individuals who have not been exposed toagents that alter the composition of oral organisms. Acomplete description of this flora can be found in Chap-ter 15. In brief, normal oral flora consists of aerobic,gram-positive cocci (primarily streptococci), actino-mycetes, anaerobic bacteria, and candidal species (Table5-1). The total numberof oral organisms is held in check

by the following four main processes: (1) rapid epithelialturnover with desquamation; (2) host immunologic fac-tors, such as salivary IgA; (3) dilution by salivary flow;and (4) competition between oral organisms for availablenutrients and attachment sites. Any agentphysical, bio-logic, or chemicalthat alters any of the forces that keeporal microbes under control will permit potentially

pathologic organisms to overgrow and set the stage for awound infection.

The flora of the nose and paranasal sinuses consistsprimarily of gram-positive aerobic streptococci andanaerobes. In addition, many children harborHaemo-

philus influenzaebacteria in these areas, and many adultshave Staphylococcus aureus as a part oftheir transient orresident nasal and paranasal sinus flora. The normal florain this region of the body is limited by the presence ofcil-iated respiratory epithelium, secretory immunoglobulins,and epithelial desquamation. The epithelial cilia moveorganisms trapped in blankets of mucus into the alimen-tary tract.

Maxillofacial skin flora. The skin of the maxillofa-cial region has surprisingly few resident organisms in itsnormal flora. The bacteria Staphylococcus epidermidis andCorynebacterium diphtheriae are the predominant species

present. Propionibacterium acnes is found in pores and hairfollicles, and many individuals carry S. aureus, spreadfrom their nose, on their facial skin (see Table 5-1).

The skin has several means of preventing surfaceorganisms from entering. The most superficial layer ofskin is comprised of keratinized epithelial cells able toresist mild trauma. In addition, epithelial cells are joined

by tight bonds that resistbacterial entrance.Processes such as the application of occlusive dressings

(which prevent skin desiccation and desquamation), as wellas dirt or dried blood (which provide increased nutrients fororganisms) and antimicrobial agents (which disturbs the

balance between various organisms) alter skin flora. Nonmaxillofacial flora. The flora below the region

of the clavicles comprises a gradually increasing numberof aerobic gram-negative and anaerobic enteric organ-isms, especially moving toward the pelvic region andunwashed fingertips. General knowledge of these bacteriais important for dental surgeons when preparing them-selves for surgery and when treating patients requiring

venipuncture or otherprocedures away from the orofa-cial region.

Viral Organisms

Viruses are ubiquitous in the environment, but fortu-nately only a few pose a serious threat to the patient andthe surgical team. The viral organisms that cause themost difficulty are the hepatitis B and C viruses, and thehuman immunodeficiency virus (HIV). These viruseshave differences in their susceptibility to inactivationthat are important to understand when attempting to

prevent their spread. Each virus is described here withrespect to hardiness and usual mode of transmission. In

addition, the circumstances in which the clinician mightsuspect that an individual is carrying one of these virusesis briefly described, allowing the surgical team to takenecessary precautions.

Hepatitis viruses. Hepatitis A, B, C, and D viruses areresponsible for most infectious hepatic diseases. HepatitisA is spread primarily by contact with the feces of infect-ed individuals. Hepatitis C may spread either throughcontaminated feces or by contaminated blood. HepatitisB and D are spreadby contact with any human secretion.

The hepatitis B virus has the most serious risk of trans-mission for unvaccinated dentists, their staffs, and their

patients. It is usually transmitted by the introduction ofinfected blood into the bloodstream of a susceptible per-

son; however, infected individuals may also secrete largeamounts ofthe virus in their saliva, which can enter an
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individual through any moist mucosal surface or epithe-lial (skin or mucosal) wound. Minute quantities of thevirus have been found capable of transmitting disease(only 105 to 107 virions/mL of blood). Unlike most viruses,the hepatitis virus is exceptionally resistant to desic-cation and chemical disinfectants, including alcohols,

phenols, and quaternary ammonium compounds. There-fore the hepatitis B virus is difficult to contain, particu-larly when oral surgery is being performed.

Fortunately, means of inactivating the virus includehalogen-containing disinfectants (e.g., iodophor, hypo-chlorite), formaldehyde, ethylene oxide gas, all types of

properly performed heat sterilization, and irradiation.These methods can be used to minimize the spread ofhepatitis from one patient to another.

In addition to preventing patient-to-patient spread,the dentist and staff also need to take precautions to pro-tect themselves from contamination, because severalinstances have occurred in which dentists have been the

primary source of a hepatitis B epidemic. Dentists who perform oral surgical procedures are exposed to bloodand saliva; therefore the dental surgery team should wear

barriers to protect against contaminating any openwounds on the hands and any exposed mucosal surfaces,This includes wearing gloves, a face mask, and eyeglassesor goggles during surgery. The dental staff should contin-ue to wear these protective devices when cleaning instru-ments and when handling impressions, casts, or speci-mens from patients. A common means of hepatitisinoculation is injury with a needle or blade that is con-taminated with blood or saliva. In addition, members ofthe dental staff should receive hepatitis B vaccinations,

which have been shown to reduce an individual's suscep-tibility to hepatitis B infection effectively, although thelongevity of protection has not been definitively deter-mined (Fig. 5-1). Finally, office-cleaning personnel andcommercial laboratory technicians can be protected by

proper segregation and labeling of contaminated objectsand by proper disposal of sharp objects (Box 5-1).

Recognition of all individuals known to be carriers of

hepatitis B and C would aid in knowing when special pre-cautions were necessary. However, only about half of thepeople infected with hepatitis ever have clinical signs andsymptoms of the infection, and some individuals whohave completely recovered from the disease still shedintact virus particles in their secretions.

The concept of universal precautions was developed toaddress the inability of health care providers to specifi-cally identify all patients with communicable diseases.The theory on which the universal precautions concept is

based is that protection of self, staff, and patients fromcontamination by using barrier techniques when treatingall patients as if they all had a communicable diseaseensures that everyone is protected from those who dohave an infectious process.

Universal precautions typically include having all doc-tors and staff who come in contact with patient blood orsecretions, whether directly or in aerosol form, wear barri-er devices, including a face mask, eye protection, andgloves. Universal precaution procedures go on to includedecontaminating or disposing of all surfaces that areexposed to patient blood, tissue, and secretions. Finally,universal precautions mandate avoidance of touching, andthereby contaminating, surfaces (e.g., the dental record,telephone) with contaminated gloves or instruments.

1.0 rn-L conlarns 20 meg ofhepatitis 8 surface intigen

icanalufn adkivast

MERCK SHARP 8 DOHME; ./. : :> : at MI : . >. \o IN ;

wesrPOINT.-wi isssa. us*

FIG. 5-1 Vaccine used to help prevent transmission of hepatitisto vaccinated individuals.


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Human immunodeficiency virus. Because of its rela-tive inability to survive outside the host organism, HIV(the cause of acquired immunodeficiency syndrome

[AIDS]), acts in a fashion similar to othersexually trans-mitted infectious disease agents. That is, transfer of thevirions from one individual to another requires directcontact between virus-laden blood or secretions from theinfected host organism and a mucosal surface or epithe-lial wound ofthe potential host. Evidence has shown thatthe HIV loses its infectivity once desiccated. In addition,extremely fewpeople carrying the HIV secrete the virusin theirsaliva, and those who do tend to secrete extremelysmall amounts. No epidemiologic evidence supports the

possibility of HIV infection by saliva alone. Even theblood of patients who are HIV-positive has low concen-trations of infectious particles (106 particles/mL as com-

pared with 1013 particles/mL in hepatitis patients). This

probably explains why professionals who are not in anyofthe known high-riskgroups for HIV positivity have anextremely low probability of contracting it, even whenexposed to theblood and secretions of large numbers of

patients who are HIV-positive during the performance ofsurgery or if accidentally autoinoculated with contami-nated blood or secretions. Nevertheless, until the trans-mission of HIV becomes fully understood, prudent sur-geons will take steps to prevent the spread of infectionfrom the HIV-carrying patient to themselves and theirassistants through the use of universal precautions,includingbarriertechniques.

In general, the universal precautions used for bacteri-al, mycotic, and other viral processes willprotect the den-

tist, office staff, and other patients from the spread of thevirus that causes AIDS (see Box 5-1). It is also importantthat patients with depressed immune function be afford-ed extra care to prevent the spread of contagions to them.Thus all patients infected with HIV who have CD4+ T-lymphocyte counts of less than 200/uL or category B orCHIV infection should be treated by doctors and stafffree of clinically evident infectious diseases. These

patients should notbe put in a circumstance in whichthey are forced to be closely exposed to patients withclinically apparent symptoms of a communicable disease.

MycobacteriaI Organisms

The only mycobacterial organism of significance to mostdentists is Mycobacterium tuberculosis. Although tubercu-losis (TB) is an uncommon disease in the United Statesand Canada, the frequent movement of people betweencountries including those where TB is common, contin-ues to spread M. tuberculosis organisms worldwide. Inaddition, some newer strains of M. tuberculosis have

become resistant to the drugs historically used to treat TB.Therefore it is important that measures be followed to

prevent the spread of TB from patients to the dentalteam.

Tuberculosis is transmitted primarily through exhaledaerosols that carry M. tuberculosis bacilli (Mtb) from theinfected lungs of one individual to the lungs of another

individual. Droplets areproducedby those with untreatedTB during breathing, coughing, sneezing, and speaking.

Mtb is not a highly contagious microorganism. However,transmission can also occur via inadequately sterilizedinstruments, because although Mtb organisms do not

form spores, they are highly resistant to desiccation and tomost chemical disinfectants. To prevent transmission oftuberculosis from an infected individual to the dentalstaff, the staff should wear face masks whenever treatingor in close contact with these patients. The organisms aresensitive to heat, ethylene oxide, and irradiation; there-fore to prevent their spread from patient to patient, allreusable instruments and supplies should be sterilizedwith heat or ethylene oxide gas. When safe to do so,

patients with untreated TB should have their surgery post-poned until they can receive treatment for their TB.

ASEPTIC TECHNIQUES AND UNIVERSAL

PRECAUTIONSTerminology

Different terms are used to describe various means of pre-venting infection. However, despite their differing defini-tions, terms such as disinfection andsterilization are oftenused interchangeably. This can lead to the misconceptionthat a certain technique or chemical has sterilized anobject when it has merely reduced the level of contami-nation. Therefore the dental team must be aware of the

precise definition of words used for the various tech-niques of asepsis.

Sepsis is the breakdown of living tissueby the action ofmicroorganisms and is usually accompanied by inflam-

mation. Thus the merepresence of microorganisms, suchas in bacteremia, does not constitute a septic state. Asep-sis refers to the avoidance of sepsis. Medical asepsis is theattempt to keep patients, health care staff, and objects asfree as possible of agents that cause infection. Surgicalasepsis is the attempt to prevent microbes from gainingaccess to traumatic surgically created wounds.

Antiseptic and disinfectantare terms that are often mis-used. Both refer to substances that can prevent the mul-tiplication of organisms capable of causing infection. Thedifference is that antiseptics are applied to living tissue,whereas disinfectants are designed for use on inanimateobjects.

Sterility is the freedom from viable forms of microor-

ganisms. It represents an absolute state; there are nodegrees of sterility. Sanitization is the reduction of thenumber of viable microorganisms to levels judged safe by

public health standards. It should not be confused withsterilization. Decontamination is similar to sanitization,except it is not connected to public health standards.

Concepts

Chemical and physical agents are the two principalmeans of reducing the number of microbes on a surface.Antiseptics, disinfectants, and ethylene oxide gas are themajor chemical means of killing microorganisms on sur-faces. Heat, irradiation, and mechanical dislodgment arethe primary physical means of eliminating viable organ-isms (Box 5-2).


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The microbes that cause human disease include bacte-ria, viruses, mycobacteria, parasites, and fungi. Themicrobes within these groups have variable ability toresist chemical or physical agents. The microorganismsmost resistant to elimination are bacterial endospores.

Therefore in general, any method of sterilization or dis-infection that kills endospores is also capable of eliminat-ing bacteria, viruses, mycobacteria, fungi, mold, and par-asites. This concept is used in monitoring the success ofdisinfection and sterilization techniques.

Techniques ofInstrument Sterilization

Any means of instrument sterilization to be used inoffice-based dental and surgical care must be reliable,

practical, and safe for the instruments. The three meth-ods generally available for instrument sterilization are dryheat, moist heat, and ethylene oxide gas.

Sterilization with heat. Heat is one of the oldest

means of destroying microorganisms. Pasteur used heatto reduce the number of pathogens in liquids for preser-vation. Koch was the first to use heat for sterilization. Hefound that 1.5 hours of dry heat at 100 C would destroyall vegetative bacteria, but that 3 hours of dry heat at140 C was necessary to eliminate the spores of anthrax

bacilli. Koch then tested moist heat and found it a moreefficient means of heat sterilization because it reduces thetemperature and time necessary to kill spores. Moist heatis probably more effective because dry heat oxidizes cell

proteins, a process requiring extremely high tempera-tures, whereas moist heat causes destructive protein coag-ulation quickly at relatively low temperatures.

Because spores are the most resistant forms of micro-

bial life, they are used to monitor sterilization tech-niques. The spore of the bacteria Bacillus stearothermo-

philus is extremely resistant to heat and is therefore usedto test the reliability ofheat sterilization. These bacilli can

be purchased by hospitals and private offices and runthrough the sterilizer with the instruments being steril-ized. A laboratory then places the heat-treated spores intoculture. If no growth occurs, the sterilization procedurewas successful (Fig. 5-2).

It has been shown that 6 months after sterilization thepossibility of organisms entering sterilization bags increas-es, although some individuals feel an even longer periodis acceptable as long as the bags are properly handled.Therefore all sterilized items should be labeled with an

expiration date that is no longer than 6 to 12 months inthe future.

FIG. 5-2 Tests of sterilization equipment. Color-coded packaging is

made of paper and cellophane; test areas on package change coloron exposure to sterilizing temperatures (top) or to ethylene oxidegas (center). Vial contains spores ofBacillus stearothermophiius, whichis used for testing efficiency of heat-sterilization equipment (bot-tom).

A useful alternative technique for sterilely storing sur-gical instruments is to place them into cassettes that aredouble wrapped in specifically designed paper and steril-ized as a set for use on a single patient.

Dry heat. Dry heat is a method of sterilization that can be provided in most dental offices because the necessaryequipment is no more complicated than a thermostati-cally controlled oven and a timer. Dry heat is most com-

monly used to sterilize glassware and bulky items thatcan withstand heat but are susceptible to rust. The suc-cess of sterilization depends not only on attaining a cer-tain temperature but also on maintaining the tempera-ture for a sufficient amount of time. Therefore thefollowing three factors must be considered when usingdry heat: (1) warm-up time for the oven and the materi-als to be sterilized, (2) heat conductivity of the materials,and (3) airflow throughout the oven and through theobjects being sterilized. In addition, time for the sterilizedequipment to cool after heating must be taken into con-sideration. The time necessary for dry-heat sterilizationlimits its practicality in the ambulatory setting, because itlengthens the turnover time and forces the dentist to

have many duplicate instruments.The advantages of dry heat are the relative ease of use

and the unlikelihood of damaging heat-resistant instru-ments. The disadvantages are the time necessary and the

potential damage to heat-sensitive equipment. Guide-lines for the use of dry-heat sterilization are provided inTable 5-2.

Moist heat. Moist heat is more efficient than dry heatfor sterilization because it is effective at much lower tem-

peratures and requires less time. The reason for this isbased on several physical principles. First, water boiling at100 C takes less time to kill organisms than does dry heatat the same temperature because water is better than air attransferring heat. Second, it takes approximately 7 times

as much heat to convert boiling water to steam as it takesto cause the same amount of room temperature water to


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*Times for dry-heat treatments do not begin until temperature ofoven reaches goal. Use spore tests weekly to judge effectiveness ofsterilization technique and equipment. Use temperature-sensitivemonitors each time equipment is used to indicate that sterilizationcycle was initiated.

boil. When steam comes into contact with an object, thesteam condenses and almost instantly releases that storedheat energy, which quickly denatures vital cell proteins.Saturated steam placed under pressure (autoclaving) is

even more efficient than nonpressurized steam. This is because increasing pressure in a container of steamincreases the boiling point of water so that the new steamentering a closed container gradually becomes hotter.Temperatures attainable by steam under pressure include109 C at 5 psi (pounds per square inch), 115 C at 10 psi,121 C at 15 psi, and 126 C at 20 psi (see Table 5-2).

The container usually used for providing steam under pressure is known as an autoclave (Fig. 5-3). It works bycreating steam and then, through a series of valves,increasing the pressure so that the steam becomes super-heated. Instruments placed into an autoclave should be

packaged to allow the free flow of steam to the equip-ment, such as by placing instruments in paper bags or

wrapping them in cotton cloth.Simply placing instruments in boiling water or free-flowing steam results in disinfection rather than steriliza-tion, because at the temperature of 100 C, many sporesand certain viruses survive.

The advantages of sterilization with moist heat are itseffectiveness, speed, and the relative availability of office-

proportioned autoclaving equipment. Disadvantagesinclude the tendency of moist heat to dull and rustinstruments and the cost of autoclaves (Table 5-3).

Gaseous sterilization. Certain gases exert a lethalaction on bacteria by destroying enzymes and other vital

biochemical structures. Of the several gases available forsterilization, ethylene oxide is the most commonly used.It is a highly flammable gas and is mixed with CO

2or

nitrogen to make it safer to use. Because ethylene oxidegas is at room temperature, it can readily diffuse through

FIG. 5-3 Office-proportioned autoclave that can be used as both

steam and dry-heat sterilizer. (Courtesy Pelton and Crane Inc., Charlotte,

NC.)

porous materials, such as plastic and rubber. At 50 C it iseffective for killing all organisms, including spores, with-in 3 hours. However, because it is highly toxic to animaltissue, equipment exposed to ethylene oxide must be aer-ated for 8 to 12 hours at 50 to 60 C or at ambient tem-

peratures for 4 to 7 days.The advantages of ethylene oxide for sterilization are

its effectiveness for sterilizing porous materials, largeequipment, and materials sensitive to heat or moisture.The disadvantages are the need for special equipment and

the length of sterilization and aeration time necessary toreduce tissue toxicity. This technique is rarely practicalfor dental use, unless the dentist has easy access to a largefacility willing to gas sterilize dental equipment (e.g., hos-

pital, ambulatory surgery center).

Techniques of Instrument Disinfection

Chemical disinfectants. Many dental instruments can-not withstand the temperatures required for heat steriliza-tion. Therefore if gaseous sterilization is not available andabsolute sterility is not required, chemical disinfection can

be performed. Chemical agents with potential disinfectantcapabilities have been classified as being high, intermedi-

ate, or low in biocidal activity. The classification is basedon the agent's ability to inactivate vegetative bacteria,tubercle bacilli, bacterial spores, nonlipid viruses, and lipidviruses. Agents with low biocidal activity are effective onlyagainst vegetative bacteria and lipid viruses, immediate dis-infectants are effective against all microbes except bacterialspores, and agents with high activity are biocidal for allmicrobes. The classification depends not only on innate

properties of the chemical but also, and just as important,on how the chemical is used (Table 5-4).

Substances acceptable for disinfecting dental instru-ments for surgery include glutaraldehyde, iodophors,chlorine compounds, and formaldehyde; glutaraldehyde-containing compounds are the most commonly used.Table 5-5 summarizes the biocidal activity of most of theacceptable disinfecting agents when used properly. Alco-hols are not suitable for general dental disinfection,


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*Crossly visible contamination, such as blood, must be removed before chemical disinfection to maximize biocidal activity.

because they evaporate too rapidly; however, they can beused to disinfect local anesthetic cartridges.

Quaternary ammonium compounds are not recom-mended for dentistry, because they are not effectiveagainst the hepatitis B virus and become inactivated bysoap and anionic agents.

Certain procedures must be followed to ensure maxi-mal disinfection, regardless of which disinfectant solu-tion is used. The agent must be properly reformulatedand discarded periodically, as specified by the manufac-

turer. Instruments must remain in contact with the solu-tion for the designated period, and no new contaminatedinstruments should be added to the solution during that

time. All instruments must be washed free of blood orother visible material before being placed in the solution.

Finally, after disinfection the instruments must berinsed free of chemicals and used within a short period oftime.

An outline of the preferred method of sterilization forselected dental instruments is presented in Table 5-6.

Maintenance of Sterility

Disposable materials. Materials and drugs used duringoral and maxillofacial surgery, such as sutures, local anes-thetics, scalpel blades, and syringes with needles, are ster-


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*Chemical disinfecting/sterilizing solutions are not the method of choice for sterilization of any items used in the mouth. In some circumstances

they may be used when other, more suitable procedures have been precluded.

tClinician should confirm with manufacturer that attachment is capable of withstanding heat sterilization.$Rinse prosthetic well, immerse in 1:10 household bleach solution (5%-6% sodium hypochlorite) for 5 minutes. Rinse the prosthetic (repeat

disinfection procedure before returning to patient).

ilizedby the manufacturerwith a variety of techniques,including gases, autoclaving, filtration, and irradiation. Tomaintain sterility the dentist must only remove the mate-rial ordrug from its container properly. Most surgical sup-

plies are double wrapped; the only common exception isscalpelblades. The outer wrapper is designed to be han-dled in a nonsterile fashion and usually is sealed in a man-ner that allows an unsterile individual to unwrap it anddischarge the material still wrapped in a sterile innerwrapper. The unsterile individual can either allow the sur-gical material in the sterile inner wrapper to drop onto asterile part of the surgical field or allow a sterilely glovedindividual to remove the wrapped material in a sterilemanner(Fig. 5-4). Scalpelblades are handled in a similarfashion; the unwrapped blade can be dropped onto thefield or grasped in a sterile manner by another individual.

Surgical field maintenance. An absolutely sterilesurgical field is impossible to attain. Fororal procedureseven a relatively clean field is difficult to maintain

because of oral and upper respiratory tract contamina-tion. Therefore during oral and maxillofacial surgery thegoal is to prevent any organisms from the surgical staff orotherpatients from entering thepatient's wound.

Once instruments are sterilized or disinfected, theyshould be set up for use during surgery in a manner thatlimits the likelihood ofcontamination by organisms for-

eign to the patient's maxillofacial flora. A flat platform,such as a Mayo stand, should be used and two layers ofsterile towels or waterproof paper should be placed on it.Then the clinician or assistant should lay the instrument

pack on the platform and open out the edges in a sterilefashion (Fig. 5-5). Anything placed on the platformshould be either sterile or disinfected. Care should betaken not to allow excessive moisture to get on the tow-els or paper; if the towels become saturated, they canallow bacteria from the unsterile undersurface to wick upto the sterile instruments.

Operatory Disinfection

The various surfaces present in the dental operatory havedifferent requirements concerning disinfection thatdepend on the potential for contamination and thedegree of patient contact with the surface. Any surfacethat a patient or their secretions contact is a potential car-rier of infectious organisms. In addition, when high-speeddrilling equipment is used, patient blood and secretionsare dispersed over much of the operatory's surfaces. Theoperatory can be disinfected in two basic ways. The first isto wipe all surfaces with a hospital-grade disinfectant solu-tion. The second is to cover surfaces with protectiveshields that are changed between each patient. Fortunate-


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FIG. 5-4 Method of sterilely transferring double-wrapped sterilesupplies from clean individual (ungloved hands) to sterilely gowned

individual (gloved hands). Package is designed to be peeied openfrom one end, without touching sterile interior of package. Sterilecontents are then promptly presented to recipient.

FIG. 5-5 Instruments to be used for extraction of erupted tooth ininstrument cassette, seen here after two layers of wrapping usedduring sterilization have been opened. Only the corners of packageare grasped, preserving sterility of both interiorof wrapping materialand instruments. Notice color-coded sterility indicator includedwhen package was wrapped.

ly, many chemical disinfectants, including chlorine compounds and glutaraldehyde, can prevent transfer of thehepatitis viruses when used on surfaces in certain concen-trations (0.2% for chlorine, 2% for glutaraldehyde). Head-rests, tray tables, hosing and lines, nitrous oxide and chaircontrols, and light handles can be covered with commer-cially available, single-use, disposable covers; the rest ofthe dental chair can be quickly sprayed with a disinfectant

(Fig. 5-6). Countertops usually come into contact withpatients only indirectly, so counters should be periodical-ly disinfected, especially before surgical procedures. Limit-ing the number of objects left on counters in operatorieswill make periodic cleaning easier and more effective.

Soap dispensers and sink faucets are another source ofcontamination. Unless they can be activated withoutusing the hands, they should be frequently disinfected

because many bacteria surviveeven thrivein a soapyenvironment (discussed later in this section). This is onereason soap is not the ideal agent when preparing handsfor surgery.

Anesthetic equipment used to deliver gases, such asoxygen or nitrous oxide, may also spread patient-to-

patient infection. Plastic nasal cannulas are designed to be discarded after one use. Nasal masks and the tubingleading to the mask from the source of the gases are avail-able in disposable form or can be covered with disposablesleeves.

Surgical Staff Preparation

The preparation of the operating team for surgery differsaccording to the nature of the procedure being performedand the location of the surgery. The two basic types of

personnel asepsis to be discussed are (1) the clean tech-nique and (2) the sterile technique. Antiseptics are usedduring each of the techniques, so they are discussed first.

Hand and arm preparation. Antiseptics are used toprepare the surgical team's hands and arms before

FIG. 5-6 A, Specially designed sterile plastic covers are used to covervarious pieces of equipment used in dental practice. B, Specially

designed sterile plastic sleeves are used to cover light handles ofdental unit to prevent the introduction of contamination from thehandle to the patient.


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gloves are donned1 and to disinfect the surgical site.Because antiseptics are used on living tissue, they aredesigned to have low-tissue toxicity while maintaining

disinfecting properties. The three antiseptics most com-monly used in dentistry are (1) iodophors, (2) chlorhex-idine, and (3) hexachlorophene.

Iodophors, such as polyvinylpyrrolidone-iodine(povidone-iodine) solution, have the broadest spectrumof antiseptic action, being effective for both gram-positiveand gram-negative bacteria, most viruses, M. tuberculosisorganisms, spores, and fungi.

Iodophors are usually formulated in a 1% iodine solu-tion. The scrub form has an added anionic detergent.Iodophors are preferred over noncompounded solutionsof iodine because they are much less toxic to tissue thanfree iodine and more water soluble. However, iodophorsare contraindicated for use on individuals sensitive to

iodinated materials, those with untreated hypothy-roidism, and pregnant women. Iodophors exert theireffect over a period of several minutes, so the solutionshould remain in contact with the surface for at least afew minutes for maxima! effect.

Chlorhexidine and hexachlorophene are other usefulantiseptics. Chlorhexidine is used extensively worldwideand is available in the United States both as a skin prepa-ration solution and for internal use. The potential for sys-temic toxicity with repeated use of hexachlorophene haslimited its use. Both agents are more effective against gram-

positive than gram-negative bacteria, which makes themuseful for maxillofacial prepping. Chlorhexidine and hexa-chiorophene are more effective when used repeatedly dur-ing the day, because they accumulate on the skin and leavea residual antibacterial effect after each wash. However,their ineffectiveness against tubercle bacilli, spores, andmany viruses makes them less effective than iodophors.

Clean technique. The clean technique is generallyused for office-based surgery that does not specificallyrequire a sterile technique. Office oral surgical proceduresthat call for a sterile technique include any surgery inwhich skin is incised. The clean technique is designed asmuch to protect the dental staff and other patients froma particular patient as it is to protect the patient from

pathogens that the dental staff may harbor.When using a clean technique, the dental staff can

wear clean street clothing covered by long-sleeved labo-ratory coats (Fig. 5-7). Another option is a dental uniform

(e.g., surgical scrubs), with no further covering or coveredby a long-sleeved surgical gown.

Dentists should wear gloves whenever they are provid-ing dental care. When the clean technique is used, thehands can be washed with antiseptic soap and dried on adisposable towel before gloving. Gloves should be sterileand put on using an appropriate technique to maintainsterility of the external surfaces. The technique of sterileself-gloving is illustrated in Fig. 5-8.

In general, eye protection should be worn when blood orsaliva are dispersed, such as when high-speed cutting equip-ment is used (see Fig. 5-7). A mask should be used whenev-er aerosols are created or a surgical wound is to be made.

In most cases it is not absolutely necessary to prepare

the operative site when using the clean technique. How-ever, when surgery in the oral cavity is performed, the

FIG. 5-7 Surgeon ready for office oral surgery, wearing clean gownover street clothes, mask over nose and mouth, cap covering scalphair, clean gloves, and shatter-resistant eye protection. Nondanglingearrings are acceptable in clean technique.

perioral skin may be decontaminated with the same solu-tions used to scrub the hands and the oral cavity prepared

by brushing or rinsing with chlorhexidine gluconate(0.12%) or an alcohol-based mouthwash. These proce-dures will reduce the amount of skin or oral mucosal con-tamination of the wound and decrease the microbial loadof any aerosols made while using high-speed drills in themouth. The dentist may desire to drape the patient to

protect the patient's clothes, to keep objects from acci-dentally entering the patient's eyes, and to decreasesuture contamination should it fall across an uncovered,unprepared part of the patient's body.

During an oral surgical procedure, only sterile water orsterile saline solution should be used to irrigate openwounds. A disposable injection syringe, a reusable bulbsyringe, or an irrigation pump connected to a bag of

intravenous solution can be used to deliver irrigation.Reservoirs feeding irrigation lines to handpieces are alsoavailable and can be filled with sterile irrigation fluids.

Sterile technique. The sterile technique is used foroffice-based surgery when skin incisions are made orwhen surgery is performed in an operating room.* Its pur-

pose is to minimize the number of organisms that enterwounds created by the surgeon. The technique requiresstrict attention to detail and cooperation among themembers of the surgical team.

The surgical hand and arm scrub is another means oflessening the chance of contaminating a patient's wound.Although sterile gloves are worn, gloves can be torn(especially when using high-speed drills or working

*A dean wound is made through intact skin that has been treatedwith an antiseptic.


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FIG. 5-8 Technique of sterile self-gloving. A, Fingers of righthand are placed into right glove; fingers of left hand hold interioredge of cuff. B, Right hand slowly pushes into glove, while lefthand pulls glove on hand. Cuff of right glove is left unturned atthis stage. C, Right hand is placed inside cuff of left glove, and lefthand is then placed into opening of left glove. Care is taken not toallow right hand to touch interiorofleft glove. Right hand remainsonly on exterior surface of left glove. D, Left hand slowly pushesinto left glove, while right hand helps to push glove on oppositehand. After fingers of left hand are completely in place, right handturns cuff down onto forearm, taking care not to let right glove?touch any nonsterile surface. E, Fingers of left fully gloved handare inserted into cuff of right glove and are used to turn that cuffdown, which completes self-gloving procedure.

around wires), thereby exposing the surgeon's skin. By proper scrubbing with antiseptic solutions, the surfacebacterial level of the hands and arms is greatly reduced.

Most hospitals have a surgical scrub protocol thatshould be followed when performing surgery in thoseinstitutions. Although several acceptable methods can beused, standard to most techniques is the use of an anti-septic soap solution, a moderately stiff brush, and a fin-gernail cleaner. The hands and forearms are wetted in ascrub sink, and the hands are kept above the level of theelbows after wetting until the hands and arms are dried.

A copious amount of antiseptic soap is applied to thehands and arms from either wall dispensers or antiseptic-impregnated scrub brushes. The antiseptic soap is allowedto remain on the arms while any dirt is removed fromunderneath each fingernail tip using a sharp-tipped fin-gernail cleaner.

Then more antiseptic soap is applied and scrubbing isbegun, with repeated firm strokes of the scrub brush onevery surface of the hands and arms up to approximately5 cm below the elbow. Scrub techniques based on thenumber of strokes to each surface are more reliable than


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FIG. 5-9 A, Scoop technique for resheathing needle. B, Self-resheathing needle. C, Proper disposal ofsharp, disposable supplies into well-marked, rigid container to prevent accidental inoculation of officestaff or cleaning workers with contaminated debris.

a set time forscrubbing. An individual's scrub techniqueshould follow a routine that hasbeen designed to ensurethat no forearm or hand surface is left improperly pre-

pared. An example of an acceptable surgical scrub tech-nique is shown in Chapter 31.

Postsurgical Asepsis

Wounds management. A few principles of postsurgicalcare are useful to prevent the spread ofpathogens.Wounds shouldbe inspected or dressedby hands that arecovered with fresh, clean gloves. When several patientsare waiting, those without infectious problems shouldbeseen first, and those with problems such as a drainingabscess shouldbe seen afterwards.

Sharps management. During and afterany surgery,contaminated materials should be disposed of in such away that the staffand other patients will not be infected.The most common riskfor transmission of disease from

infected patients to the staff is by accidental needle sticksor scalpel lacerations. Sharps injuries can be prevented byusing the local anesthetic needle to scoop out the sheathafter use or using automatically resheathing needles; tak-

ing care never to apply or remove a blade from a scalpelhandle without an instrument (Fig. 5-9,A); and disposingof used blades, needles, and other sharp disposable itemsinto rigid, well-marked receptacles specially designed forcontaminated sharp objects (Fig. 5-9, B). For environ-mental protection, contaminated supplies should be dis-carded in properly labeled bags and removed by a rep-utable hazardous waste management company.

B IBL IOGRAPHY

ADA Councils on Dental Materials, Instruments, and Equip-ment; Dental Practice; and Dental Therapeutics: Infection con-trol recommendations of the dental office and the dental labo-ratory,] Am DentAssoc 118(suppl):l, 1992.

Bird DL, Robinson DS: Torres and Ehrlich modem dental assist-ing, ed 7, Philadelphia, 2003, WB Saundcrs.

Cottone JA, Terezhalmy GT, Molinari JA: Practical infectioncontrol in dentistry, ed 2, Baltimore, 1996, Williams & Wilkins.

Daniel S, Harfst S: Mosby's dental hygiene: concepts, cases andcompetencies, St Louis, 2002, Mosby.

Miller CH, Palenik CJ:Infection control and management of haz-ardous materials for the dental team, St Louis, 1998, Mosby.
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5 Infection Control in Surgical Practice