Category Archives: Infection Control in Surgical Practice

Treatment of Long-Standing Communications

Treatment of Lon’g-Stariding Communications

Successful treatment and closure of the oroantral communication requires extensive surgery. Aggressive antibiotic treatment is lso necessary. If the fistula has developed’ next to the root of an adjacent tooth, closure is further complicated and, to be successful, removal of the tooth may be necessary. Surgeons use various techniques to close oroantral fistulas .or communications. Some techniques involve mobilization and rotation of large mucosal flaps to cover , the osseous defect with soft tissues, the margins of which are sutured over and therefore supported by intact bone. , The mucosal flaps must be designed to have a good blood supply and to alter the surrounding anatomy to the smallest extent possible. If sinus disease exists, it may be necessary to remove diseased tissues from the sinus using Caldwell-Luc procedure through the ateral maxillary wall above the apices of the remaining teeth. The Caldwell-Luc procedure includes the creation of an opening into the nose at the level of the sinus floor beneath the inferior turbinate to allow drainage of secretions  of the sinus mucosa into the nasal cavity. This porttoa of the procedure is termed nasal antrostomy. Other methods of closing oroantral fistulae include buccal flap advancement (Fig. 19-13), palatal flap advancement (Fig. 19-14), and advancement of both palatal and facial flaps over a metallic-foil plate. This plate is adapted to the contour of the alveolar process in the fistulous tract area and Interposed between th~ alveolar bone and verlying mucosal flaps (Hg. 19-15 on pages 4?1-433). The metal foil technique provides a );.hysical barrier over the osseous defect and also a more stable };I,atform tc support the mucosal flaps.  Regardless of the technique used, it must be remember that the osseous defect surrounding the fistula is always much larger than the clinically apparent soft tissue deformity. Surgical planning of closure technique must be adjusted accordingly,

alveolar process. Incision for closure of fistula with buccal flap advancement procedure is ouUined. The fistulous tract Itself wiI be excised. In addition, the margins of flap are wide enough to rest on bone when advanced to cover osseous defect. B, Elevated buccal flap. Rap-is released to depth of labial YeStlbuIe.If necesSary, periosteum may be incised on deep surface of flap to allow advancement of soft tissue to cover osseous defect without placing flap under tension. C, Advanced anG sutured buccal flap. Rap must be positioned with minimal tension and Its margins supported by underlying bone to ensure adequate closure of fistulous defect. 0, Crou-sectIon of buccal flap closure of oroantral fistula. Buccal flap has been elevated and underlying periosteum Incised to Improve mobility of flap. Continued

alveolar process. Incision for closure of fistula with buccal flap advancement procedure is ouUined. The
fistulous tract Itself wiI be excised. In addition, the margins of flap are wide enough to rest on bone
when advanced to cover osseous defect. B, Elevated buccal flap. Rap-is released to depth of labial
YeStlbuIe.If necesSary, periosteum may be incised on deep surface of flap to allow advancement of soft
tissue to cover osseous defect without placing flap under tension. C, Advanced anG sutured buccal
flap. Rap must be positioned with minimal tension and Its margins supported by underlying bone to
ensure adequate closure of fistulous defect. 0, Crou-sectIon of buccal flap closure of oroantral fistula.
Buccal flap has been elevated and underlying periosteum Incised to Improve mobility of flap.
Continued

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FIG. 19-14 Palatal flap closure of· oroantral communications. A, Diagrammatic illustration of oroat"Itrai fistuloUs tract in right maxillary alveQlar process In region of second molar, which is to be dosed with rotatjon of palatal flap. Anterior' palatine artery must be included in flap to provide adequate blood supply to transpositloned soft tis.;ues.• , Soft tissues surrounding oroantral opening are excised, exposing underlying alveolar bOne around osseous defect. Palatal flap is outlined, incised, and elevated from anterior to posterior. Flap snould be full thickness of mucoperiosteum, should have broad posterior base, and should include'anterior palatine artery. Its width should be sufficient to cover entire defect around oroa~~tr!!opening, and its length must be adequate to allow rotation of flap and repositioning over defect without placing undue tension on flap. C, Palatal flap has been rotated to cover !>Sseousdefect in alveolar process and sutured in'place, Exposed bone on palate, Which remains after rotation of flap, will heal by secondal) intentil)O with minimal discomfort to patient and little or . . no alteration In normal soft tissue anato~.

FIG. 19-14 Palatal flap closure of· oroantral communications. A, Diagrammatic illustration of
oroat”Itrai fistuloUs tract in right maxillary alveQlar process In region of second molar, which is to be
dosed with rotatjon of palatal flap. Anterior’ palatine artery must be included in flap to provide adequate
blood supply to transpositloned soft tis.;ues.• , Soft tissues surrounding oroantral opening are
excised, exposing underlying alveolar bOne around osseous defect. Palatal flap is outlined, incised, and
elevated from anterior to posterior. Flap snould be full thickness of mucoperiosteum, should have
broad posterior base, and should include’anterior palatine artery. Its width should be sufficient to cover
entire defect around oroa~~tr!!opening, and its length must be adequate to allow rotation of flap and
repositioning over defect without placing undue tension on flap. C, Palatal flap has been rotated to
cover !>Sseousdefect in alveolar process and sutured in’place, Exposed bone on palate, Which remains
after rotation of flap, will heal by secondal) intentil)O with minimal discomfort to patient and little or
. . no alteration In normal soft tissue anato~.

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FIG. 19- 14--cont' d D, Large oroantral communication in left maxilla that developed after reo moval of second molar tooth. E, Pa'lat~1 flap outlined. Flap is posteriorly based and receives its blood supply from anterior palatine neurovascular bundle. Width of flap is much larger than clinical oroantral communication.' F, Palatal flap is elevated and readied for transposition laterally to cover osseous oroantral defect. Buccal mucosa has also been elevated to facilitate suturing of flap. Larye size of osseous defect is demonstrated. Continued

FIG. 19- 14–cont’ d D, Large oroantral communication in left maxilla that developed after reo
moval of second molar tooth. E, Pa’lat~1 flap outlined. Flap is posteriorly based and receives its
blood supply from anterior palatine neurovascular bundle. Width of flap is much larger than
clinical oroantral communication.’ F, Palatal flap is elevated and readied for transposition laterally
to cover osseous oroantral defect. Buccal mucosa has also been elevated to facilitate suturing
of flap. Larye size of osseous defect is demonstrated.
Continued

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contrd E,Metallic-foil patch has been positioned between alveolar process and deep surface of buccal and palatal mucoperiosteal flaps. Foil is entirely supported on its margins by underlying bone. Mucoperiosteal flaps are repositioned  and. approximated over foil. F, Oroantral fistula of several weeks’ duration in riqht posterior maxilla that developed secondary to removal of retained first molar tooth root. G, Elevation of 11Irgebuccal and palatal mucoperiosteal flaps has been corn-: pleted. Large size ‘of exposed alveolar . osseous defect is demonstrated. H, Titanium foil patch has been adapted. over defect in alveolar process. Foil is inserted beneath facial and. palatal mucosa and covers mini

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Surgicai Staff Preparation

Surgicai Staff Preparationa

The preparation of the operating team for surgery differs
according to the nature of the procedure being performed
and the location of the’ surgery. The two basic types of
personnel asepsis to be discussed are (1) the clean technique
and (2) the sterile technique. Antiseptics are used
during each of the techniques, so th.ey are discussed firs.

Iodophors, such as polyvinylpyrrolidone-iodine
(povidone-iodine) solution, have the broadest spectrum
of antiseptic action, being effective for both grarn-posittve
and gram-negative bacteria, most viruses, M. tuberculosis
organisms, spores, and fungi.
Iodophors are usually formulated in a 1% iodine solution.
The scrub form has an added anionic detergent.
lodophors are preferred over noncompounded solutions
of iodine because they-are much less toxic to tissue than
free iodine and more water soluble. However, iodophors
are contraindicated for use on individuals ‘scnsttive to
iodinated materials, those with untreated hypothyroidism,
and pregnant women. Iodophors exert their
effect over a period of several minutes, so the solution
should remain in contact with the surface for at least a
few minutes for maximal effect.

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

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

Dentists should wear gloves whenever they arc providing
dental care. \\’hen the clean technique is used, the
hands can be washed with antiseptic soap and dried on a
disposable towel before gloving. Glows should be sterile
and put an using an appropriate technique to maintain
sterility of the external surfaces. The technique of sterile
self-gloving is illustrated in Fig. 5-8.
In general, eye protection should be worn whenblood or
saliva are dispersed, such as when high-speed cutting equipment
is used (see l-ig. 5-7j. A mask should be used whenever
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. llowever,
when surgery in the .oral cavity is performed, theperioral skin may be decontaminated with toe same solutions
used to scrub the hands and the oral cavity prepared
by brushing or rinsing ‘with chlorhexidine gluconate
(O.12’h» or an alcohol-based mouthwash. These procedures
will reduce the amount of skin or oral mucosal contamination
of the wound and decrease the microbial load
of any aerosols made while using high-speed drills in the
mouth. The dentist may desire to drape the patient to
protect the patient’s clothes, to keep objects from accidentally
entering the patient’s eyes, and to decrease
suture contamination should it fall across an uncovered,
unprepared part of the patient’s body.

The surgical hand and arm scrub is another means of
lessening till’ chance of contaminating a patient’s wound.
,\lthuu.~ll ,tenlL’ gloves are worn, gloves can be torn
cespcciall;: when using high-speed drills or working

 

around wires), thereby exposing the surgeon’s skin. By
proper scrubbing with antiseptic solution, the surface
bacterial level of the hands and arms is greatly reduced.
Most hospitals have a surgical scrub protocol that
should be followed when performing surgery in those
institutions .. ‘\ltl1ough several acceptable methods can be
used, standard to most techniques is the use of an antiseptic
soap ~l lution, a modcratelv stiff brush, and a’ fin-
.geruatl cu ancr, The hands and f~rearms are wetted in a
scrub sink, and the hands are kept above the level of the
elbows after wetting until the hands and arms are dried.

Then more antiseptic soap is applied and vcruhbiru; is
begun, with repeated firm strokes of the scruli brush on
everv surface of the hands and arms up to npproxuu.itclv
.) ern below the elbow, Scrub techniques based on tl e
number of strokes to each surface are more reliable than

FIG. 5-8 Technique of sterile self-gloving. A, Fingers of right hand are placed into right glove; fingers of left hand hold interior edge of cuff. B, Right hand slowly pushes into glove, while left hand pulis glove on hand. Cuff of right glove is left unturned at this stage. C, Right hand is placed inside cuff of left glove, and left hand is then placed into opening of left glove. Care is taken not to allow right hand to touch interior of left glove. Right hand remains only on exterior surface of left glove. 0, Left hand slowly pushes into left glove, while right hand helps to push glove on opposue hand. After fingers of left hand are completely in place, right hand turns- cuff down onto forearm, taking care not to let right glove touch any nonsterile surface. E, Fingers of left fully gloved hand are inserted into 'cuff of right glove and are used to turn that cuff down, which completes self-gloving procedure

FIG. 5-8 Technique of sterile self-gloving. A, Fingers of right
hand are placed into right glove; fingers of left hand hold interior
edge of cuff. B, Right hand slowly pushes into glove, while left
hand pulis glove on hand. Cuff of right glove is left unturned at
this stage. C, Right hand is placed inside cuff of left glove, and left
hand is then placed into opening of left glove. Care is taken not to
allow right hand to touch interior of left glove. Right hand remains
only on exterior surface of left glove. 0, Left hand slowly pushes
into left glove, while right hand helps to push glove on opposue
hand. After fingers of left hand are completely in place, right hand
turns- cuff down onto forearm, taking care not to let right glove
touch any nonsterile surface. E, Fingers of left fully gloved hand
are inserted into ‘cuff of right glove and are used to turn that cuff
down, which completes self-gloving procedure

a set timefor scrubbing. An individual’s scrub technique
should follow a routine that has been designed to ensure
that’ no forearm or hand surface is left improperly pre-
,pared. An example of an acceptable surgical scrub technique
is shown in Chapter 31.

Postsurqlcal Asepsis

Wounds management. A few principles of postsurgical
‘care are useful to prevent the spread of pathogens.
Wounds should Be inspected or dressed by hands that are
covered with fresh, clean gloves, When several” patients
are waiting, those without infectious problems should be
seen first, and those with problems such as a draining
abscess should be seen afterwards.

Taikng care never to apply or remove a blade from a scalpel
handle without an instrument (Fig. 5-9, A); and disposing
of used blades, needles, and other sharp disposable items
into rigid, well-marked receptacles specially designed for
contaminated sharp objects (Fig.’ 5-9, B). For environmental
protection, contaminated supplies should be discarded
in properly labeled bags and removed by a reputable
hazardous waste management company.

 

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

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

BIBLIOGRAPHY

ADA Councils on Dental Materials, Instruments, and Equipment;
Dental Practice; and Dental Therapeutics: Infection control
recommendations of the dental office and the dental labo-
-ratory, J Am Dent Assoc 118(suppl):I, 1992.
Bird DL, Robinson DS: Torres and Ehrlicu modem dentul assisting,
ed 7, Philadelphia, 2003, WB Saunders.
Cottone JA, Terezhalmy GT, Molinart jA: Practicalinfection
control ill dentistl)~ ed 2, Baltimore, 1996, Williams & Wilkins.
Daniel ‘5, Harfst 5: .\10~br·s dental 1z):~iC’ll(,: lOIlCCP/), cases cilld
competencies, St Louis, 2002, Mosby.
Miller CH. Palenik C): infection control and IIlIlllag(‘m(,lIt othaz-
II/dOllS materials (or the dental tea III, 51 Louis, 1998, Mosby

Operatory Disinfection

Operatory Disinfection

The various surfaces present in the dental opera tory have different requirements concerning disinfection that depend on the potential for contamination and the degree of patient contact with the surface. Any surface
that a patient or their secretions contact is a potential carrier of infectious organisms, In addition, when high-speed drilling equipment is used, patient blood and secretions are dispersed over much of the opera tory’s surfaces. The operatory can be disinfected in two basic ways. The first is
to wjpe all surfaces With a hospital-grade disinfectant solution. The second is to cover surfaces with protective shields that are changed betwee.n…. each patient. Fortunate.

FIG. 5-4 Method of sterilely transferring double-wrapped sterile supplies from clean individual (ungloved hands) to sterilely gowned individual (gloved hands). Package is designed to be peeled open from one end, without touching sterile interior of package. Sterile contents are then promptly presented to recipient

FIG. 5-4 Method of sterilely transferring double-wrapped sterile
supplies from clean individual (ungloved hands) to sterilely gowned
individual (gloved hands). Package is designed to be peeled open
from one end, without touching sterile interior of package. Sterile
contents are then promptly presented to recipient

ly, many chemical disinfectants, including chlorine compounds and glutaraldehyde, can prevent transfer, of the hepatitis viruses when used on surfaces in certain concentrations (0.2% for chlorine, 2% for glutaraldehyde). Headrests, tray tables, hosing and lines, nitrous oxide and chair controls, and light handles can be covered with oommercially
available, single-use, disposable covers; the rest of the dental chair can be quickly sprayed with a disinfectant (Fig. 5-6). Countertops usually come into contact with patients only indirectly, so counters should be periodically disinfected, especially before surgical procedures. Limiting
the number of object’s left on counters in operatories will make periodic cleaning easier and more effective.

Soap dispensers and sink faucets are another source of contamination. ‘Bnless they can be activated without using the hands, they should be frequently disinfected because many bacteria” survive-even thrive-in a soapy environment (discussed later in this section). This is one
reason soap is not the ideal agent when preparing hands for surgery.

Anesthetic equipment used to deliver gases, such as oxygen or nitrous oxide, may also spread patient-topatient infection. Plastic nasal cannulas are designed to be discarded after one use. Nasal masks and the tubing
leading to the mask from the source of the gases are available in disposable form or can be covered with disposable sleeves.

 

 

Maintenance of Sterility

Maintenance of Sterility 

Disposable material Materials and drugs use oral and maxillofacial surgery, such a as , scalpel blades, and syringes with needles are sterilization

TABLE 5-6

Methods of Sterilization or Disinfection ‘of Selected Dental Instruments

·Chemical disinfecting/ster+lizing solutions are not the method of choice for sterilization of any items used in the mouth. In some circum- .stances t~ey may be used when other, more suitable procedures have been precluded. . Clinician should confirm with manufacturer that attachment is capable of withstanding heat sterilizat!<>n. tRiose 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).

·Chemical disinfecting/ster+lizing solutions are not the method of choice for sterilization of any items used in the mouth. In some circum-
.stances t~ey may be used when other, more suitable procedures have been precluded. .
Clinician should confirm with manufacturer that attachment is capable of withstanding heat sterilizat!<>n.
tRiose 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).

by the manufacturer with a variety of techniques, including gases, autoclaving, filtration, and irradiation. To maintain sterility the dentist must only remove the material or drug from its container properly. Most surgical supplies are double wrapped; the only common exception is
scalpel blades. The outer wrapper is designed to be handled in a nonsterile fashion and usually is sealed in a manner that allows an unsterile Individual to unwrap it and discharge the material still wrapped in a sterile inner
wrapper. The unsterile individual can either allow the surgical material in the sterile inner wrapper to drop onto a sterile part of the surgical field or allow a sterilely gloved individual to remove the wrapped material in a sterilized manner (Fig. 5-4). Scalpel blades are handled in a similar
fashion; the unwrapped blade can be dropped onto the field or grasped in a sterile manner by another individual.
Surgical field 11IailltCI/(IIICC. An absolutely sterile surgical field is impossible to attain. For oral procedures even a relatively clean field is difficult to maintain because of oral and upper respiratory tract contamination. Therefore during oral and maxillofacial surgery the
goal is to prevent any organisms from the surgical staff or other patients from entering the patient’s wound.
Once instruments are sterilized or disinfected, they should be set up for use during surgery in ‘I manner that limits the likelihood of contamination by organisms foreign foreign to the patient’s maxillofacial flora. A flat platform, such as a Mayo stand, should be used and two Iayers of
sterile 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 sterile fashion (Fig. 5-5). Anything placed on the platform should be either sterile or disinfected. Care should be
taken not to allow excessive moisture to get on the towels or paper; if the towels become saturated, they can allow bacteria from the unsterile undersurface to wick up to the sterile instruments.

 

 

Techniques of Instrument Disinfection

Techniques of Instrument Disinfection

Clicnticul disinfectants. Many dental instruments cannot withstand the temperatures required for heat sterilization. Therefore if gaseous sterilization is not available and absolute sterility is not required, chemical disinfection can be performed. Chemical agents-with potential disinfectant
capabilities have been classified as being high, intermediate, or low in biocidal activity. The classification is based on the agent’s ability to inactivate vegetative bacteria, tubercle bacilli, bacterial spores, nonlipid viruses, and lipid viruses. Agents with low biocidal activity are effective only against vegetative bacteria and lipid viruses, immediate disinfectants
are effective against all microbes except bacterial spores, and agents with high activity are biocidal for all microbes. 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 instruments for surgery include glutaraldehyde, iodophors, chlorine compounds, and  ormaldehyde; glutaraldehydecontaining compounds are the most commonly used. Table 5-5 summarizes the biocidal activity of most of the
acceptable disinfecting agents when used properly. Alcohols are not suitable for general dental disinfection,

Table 5-3

Comparison of Dry-Heat versus Moist-Heat Sterilization Techniques

 

Comparison of Dry-Heat versus Moist-Heat Sterilization Techniques

Comparison of Dry-Heat versus Moist-Heat
Sterilization Techniques

TABLE 5-4

Classification System for the Biocidal. Effects of Chemical Disinfectants

In absence of gross organic materials on surfaces being disinfected.

In absence of gross organic materials on surfaces being disinfected.

TABLE  5-5

Biocidal Activity of Various Chemical Disinfectants

'Grossly visible contamir'lation, such ~ blood, must be removed before chemical disinfection to maximize biocidal activity,'Grossly visible contamir'lation, such ~ blood, must be removed before chemical disinfection to maximize biocidal activity,

Grossly visible contamir’lation, such ~ blood, must be removed before chemical disinfection to maximize biocidal activity.

because they evaporate too rapidly; however, they can be used to disinfect local anesthetic cartridges, Quaternary ammonium compounds arc not recommended for dentistry, because they are not effective against the hepatitis B virus and become inactivated by soap and anionic agents.
Certain procedures must be followed to ensure maxia disinfection, regardless of which disinfectant solution used. The agent must be properly reformulated added periodically, as specified by the manufacm
nts must remain in contact with the solui nated period, and no new contaminated o Id be added to the solution during thattime. All. instruments must be washed free- of blood or other visible material before being placed in the solution. Finally

After disinfection the instruments must be rinsed free of chemicals and used within a short period of time.

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

 

 

Techniques of Instrument Sterilization

Techniques of Instrument Sterilization

Any means of instrument sterilization. to be used in  office-based dental and surgical care must be reliable, practical, and safe for the instruments. The, three methods generally available for instrument sterilization are dry heat, moist heat, and ethylene oxide gas.

Sterilization with heat. HeatIs one of the ‘oldest means of destroying microorganisms. Pasteur used heat ‘to reduce the number of pathogens in liquids for preservation. Kcch was the first to use heatfor sterilization. He
found that 1.5 hours of dry heat at 1000 C would destroy all vegetative bacteria, but that 3 hours of dry heat at 1400 C was necessary to eliminate the ‘spores of anthrax bacilli. Koch then tested moist heat and found it a more efficient means of heat sterilizatio~ because it reduces the
temperature and ‘time necessary to kill spores. Moist heat is probably more effective because dry heat oxidizes cell proteins, a process requiring extremely high temperatures, whereas moist heat causes destructive protein calculation quickly at relatively low, temperatures.

Because spores are the most resistant forms of microbial life, they are used to monitor sterilization techniques. The spore of the bacteria Bacillus stearothermophilus is extremely resistant to heat and is therefore used
to test the reliability of heat sterilization. These bacilli can . be purchased by hospitals and private offices and run through the sterilizer .with the instruments being sterilized. A laboratory then places the heat-treated spores into culture. If no growth occurs, the sterilization procedure
was successful (Fig. 5-2).
It has been’ shown that 6 months after sterilization the possibility of organisms entering sterilization bags increases, although some individuals feel an even longer period is 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 in the future.

FIG, 5-2 Tests of sterilization equipment. Color-coded packaging IS made of. paper and cellophane; test areas on package change color on exposure to sterilizing temperatures (top) or to ethylene oxide g~s (center). Vial contains sporesof Bacillus stearothermophilus, which is USE:<.! for testing efficiency of heat-sterilization equipment (bottom

FIG, 5-2 Tests of sterilization equipment. Color-coded packaging IS
made of. paper and cellophane; test areas on package change color
on exposure to sterilizing temperatures (top) or to ethylene oxide
g~s (center). Vial contains sporesof Bacillus stearothermophilus, which
is USE:<.! for testing efficiency of heat-sterilization equipment (bottom

A useful alternative technique for sterilely storing surgical instruments is to place them into cassettes that are double wrapped in specifically designed paper and sterilized as a set foruse on a single patient.
Dry heat. Dry heat is a method of sterilization that can be provided in most dental offices because the necessary equipment is no more complicated than a therrriostatically controlled oven and a timer. Dry heat is most commonly used to sterilize glassware and bulky items that can withstand heat but are susceptible to rust, The success of sterilization depends not only on attaining a certain temperature but also on maintaining the temperature for a sufficient amount of time. Therefore the following three factors must be considered when using dry heat: (1) warm-up time for the oven and the materials to be sterilized, (2) heat conductivity of the materials, and (3) airflow throughout the oven and through the
objects being sterilized. In addition, time for the sterilized equipment to cool after heating must be taken into consideration. The time necessary for dry-heat stenllzation limits its practicality in the ambulatory settingbecause it lengthens 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 instruments. The disadvantages are the time necessary and the potential damage to heat-sensitive equipment. Guidelines for the use of dry-heat sterilization are provid u in Table 5-2.

Moist heat. Moist heat is more efficient than dry heat  for sterilization because it is effective at much lower temperatures and requires less time, The reason for this IS based on several physical principles. First, water boilin 100° C takes less time to kill organisms than does not at the same temperature because water is boiling fransferring heat. Second, it takes approxm a as much heat to convert ·boiling water temperature cause the same amount of room temperature

TABLE 5-2

Guidelines for Dry-Heat and Steam Sterilization

'Times for dry-heat treatments do not begin until temperature of oven reaches goal. Use spore tests weekly to judge effectiveness of sterilization technique and equipment. Use temperature-sensitive monitors each time equipment is used to indicate that sterilizatlon cycle was initiated

‘Times for dry-heat treatments do not begin until temperature of
oven reaches goal. Use spore tests weekly to judge effectiveness of
sterilization technique and equipment. Use temperature-sensitive
monitors each time equipment is used to indicate that sterilizatlon
cycle was initiated

boil. When steam comes into contact with an object, the “:\:’am condenses and almost instantly releases that stored ; .cat energy, which quickly denatures vital cell proteins. Saturated steam placed under pressure (autoclavtng) is even more efficient than non pressurized steam. This is
because increasing pressure in a container of steam increases the boiling point of water so that the new steam entering a Closed container gradually becomes hotter. Temperatures attainable by steam under pressure include.
1090 C at 5 psi (pounds per square inch), 1150 C at 10 psi, 121″ C at 15 psi, and 1260 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 ‘.•o•.rks by creating steam and then, through a series of valves, increasing the pressure so that, the steam becomes superheated. Instruments placed into an autoclave should be packaged to allow the free flow of steam to the equipment, such as by placing instruments in paper bags or wrapping them in cotton ‘cloth.
Simply placing instruments in boiling water or freedflowing steam results in disinfection rather than sterilization, because at the temperature of 100” C, many spores and certain viruses survive.

The advantages 01 sterilization with moist heat are its cttecuvcncss.vpeed. and the relative availability of office proportioned auto claving equipment. Disadvantages include the tendency of moist heat to dull and rust instruments and the cost of autoclaves Crable 5-3).

Gaseous Steriliztion. Certain gases exert a lethal action on bacteria by destroying enzymes and other vital medical structures Of the several gases available for sterilizationl, ethylen oxide is the most commonly used.
It is a highly framablc gas and is mixed with CO, or nitrogen to make it safer to use. Because ethylene oxide gas is at room temperature, it can readily diffuse through

•.Ie. :>-:;; Office-proportioned autoclave that can be used as both steam and dry-heat sterilizer. (Courtesy Pelton ond Crone inc., Char/otte, NC)

FIG 5-3 Office-proportioned autoclave that can be used as both
steam and dry-heat sterilizer. (Courtesy Pelton ond Crone inc., Char/otte,
NC)

porous materials, such as plastic and rubber.At 50° C it is effective for killing all or&anfsms, including spores, within 3 hours. However, because it is highly tcxic to animal tissue, equipment exposed to ethy.lene oxide must be aerated for 8 to 12 hours..at 50° to 60° C or at ambient temperatures
for 4 to 7 days.
The advantages of ethylerie oxide’ for sterilization are its effectiveness for sterilizing porous materials, large equipment’, and materials sensitive. to heat or moisture. The disadvantages are the need for special equipment and
the length of sterilization and aeration time necessary to reduce tissue toxicity. This technique is rarely practical for dental use, unless the dentist has easy access to a large facility willing to gas sterilize dental equipment (e.g., hospital, ambulatory surgery center).

 

 

 

Concepts

Concepts

Chemical and physical agents are the two principal means of reducing-the number of microbes on a surface. Antiseptics, disinfectants, and ethylene oxide gas are the major chemical means of killing microorganisms on surfaces.
Heat, irradiation, and mechanical dislodgment are the primary physical means of eliminating viable organisms (Box 5-2).

BOX 5-2

General Methods of Reducing the Number of Viable Organisms from a Surface

General Methods of Reducing the Number of Viable Organisms from a Surface

General Methods of Reducing the Number of Viable
Organisms from a Surface

The microbes that cause human disease include bacteria, viruses, mycobacteria, parasites. and fungi. The microbes within these, groups have variable ability to resist chemical or physical agents. The microorganisms
most resistant to elimination are bacterial endospores. Therefore in general, any method of sterilization or disinfection that kiils endospores is also capable of eliminating bacteria, viruses, mycobacteria, fungi, mold, and parasites. This concept is used in monitoring the success of disinfection and sterilization techniques.

 

 

ASEPTIC TECHNIQUES AND UNIVERSAL PRECAUTIONS

ASEPTIC TECHNIQUES AND UNIVERSAL PRECAUTIONS

Terminology

Different terms are used to describe various means of preventing infection. However, despite their differing definitions, terms such as disinfection arid sterilization are often used interchangeably. This can lead to the misconception that a certain technique or chemical has sterilized an
object when it has merely reduced the level of contamination.
Therefore the dental team must be aware of the precise definition of words used for the various techniques of asepsis.
Sepsis is the breakdown of living tissue by the action of microorganisms and is usually accompanied by inflammation. Thus the mere presence of microorganisms, such as in bacteremia, does not constitute .a septic state. Asepsis refers to the avoidance of sepsis. Medical asepsis is the attempt  to keep patients, health care staff, and objects as free as possible of agents that cause infection. Surgicai asepsis is the attempt to prevent microbes from gaining access to traumatic surgically created wounds.

Antiseptic and disinfectant are terms that are often miused. Both refer to substances that can prevent the multiplication of organisms capable of causing infection. The difference is that antiseptics are applied to living tissue, whereas disinfectan ts are designed for use on inanimate objects.

Sterilityis the freedom from viable forms of microorganisms. It represents an absolute state; there are no degrees of sterility. Sanitization is the reduction of the number of viable microorganisms to levels judgedsafe by
public health standards. It should not be confused with sterilization. Decontamination is similar to sanitization, except it is not connected to public health standards.

Mycobacterial Organisms

Mycobacterial Organisms

The only mycobacterial organism of significance to most dentists is sivcobncteruun tuberculosis. Although tuberculosis (TB) is an uncommon di ease in the United States and Canada, the frequent movement of people between countries inclucing those where Tll is common, continues
to spread M, tuberculosis organisms worldwide. In addition, some newer strains of M, tuberculosis have become resistant tothe drugs historically used to treat TB, Therefore it is important that measures be followed to
prevent the spread of TB from patients to the dental team.
Tuberculosis is transmitted primarily through exhaled aerosols that carry M. tuberculosis bacilli (Mtb) from the infected lungs of one individual to the lungs of another individual. Droplets are produced by those with untreated
. TB during breathing, coughing, sneezing, and speaklng. Mtb is not a highly contagious microorganism. However, transmission can also occur via inadequately sterilized instruments, because although Mtb organisms do not  form spores, they are highly resistant to desiccation and to most chemical disinfectants.’ To prevent transmission of tuberculosis from an infected individual to the dental ‘staff, the staff should wear face masks whenever treating or in closecontact with these patients. The organisms are
sensitive to heat, ethylene oxide, and irradiation; therefore to prevent their spread fJom patient to patient, all reusable instruments and supplies should be sterilized with heat or ethylene oxide gas. When safe to do so,
patients with untreated TB should have their surgery postponed until they can receive treatment for their TB.

Viral Organisms

Viral Organisms

Viruses are ubiquitous in the environment, but fortunately only a few poseerious threat to the patient and the surgical team. The viral organisms that- cause the most difficulty are. the hepatitis Band C viruses, and the
human immunodeficiencv virus (HIVi. These viruses have differences in their’ susceptibility to nation that are important to understand when attempting to
prevent their spread. Each virus is described here with respect to hardiness and usual mode of transmission. In addition, the circumstances in which the clinician might suspect that an individual is carrying one of these viruses
is briefly described, allowing the surgical team. to take necessary precautions.

Hcpatitis viruses. Hepatitis A, B, C, and D viruses are responsible for most infectious hepatic diseases. Hepatitis A is spread primarily by contact with the feces of infected individuals. Hepatitis C may spread either through
contaminated feces or by contaminated blood. Hepatitis’ Band D are spread by contact with any human secretion.

The hepatitis B virus has the most serious risk of transmission for unvaccinated dentists, their staffs, and their patients. It is usually transmitted by the introduction of infected blood into the bloodstream of a susceptible person; however, infected individuals may also crete large
amounts of the virus in their saliva, which can enter an  individual through any moist mucosal surface or eplthe   1 or mucoval) wound. xtmute quantities of the ,ru have been found capable of transmitting disease
only 10″ to 10′ virions/nil, of 9100d). Unlike most virus the hepatitis virus is exceptionally resistant to desiecatlon  and chemical dlslnfeftants, including alcohols, phenols, and quaternary ammonium compounds. There- in the hepatitis B virus is difficult to contain, particularly
when oral surgery is being performed.

Fortunately, means of inactivating the virus include halogen-containing disinfectants (e.g., iodophor, hypohlorite), formaldehyde, ethylene oxide gas, all types of properly performed heat sterilization, and irradiation.
These methods can be used to minimize the spread of hepatitis from one patient to another.

In addition to preventing patient-to-patient spread, the dentist and staff also need to take precautions to protect themselves from contamination, because several instances haw occurred in which dentists have been the
prlmary source of a hepatitis B epidemic. Dentists who perform oral surgical procedures are exposed to blood and saliva; therefore the dental surgery team should wear barriers to protect against contaminating any open wounds on the hands and any exposed mucosal surfaces.
This includes wearing gloves, a face mask, and eyeglasses or goggles during surgery. The dental staff should continue to wear these protective devices when cleaning instruments and when handling impressions, casts, ‘or specimens from jJiltients. A common means of hepatitis inoculation is injury with a needle or blade that is contaminated with blood or saliva. In addition, members of the dental staff should receive hepatitis B vaccinations, which have been shown to reduce an individual’s susceptibility to hepatitis B infection effectively, although the
longevity of protection has not been definitively determined (Fig. 5-11. Finally. office-cleaning personnel and cornmerclal Taborator , technicians can be protected by

f-IG. :,., 'Vaccine used to help prevent transrnission of hepatitis B to vaccinated individuals

f-IG. :,., ‘Vaccine used to help prevent transrnission of hepatitis B
to vaccinated individuals

proper segregation and Jabeling of contaminated obit?
and by proper disposal of sharp objects (Box 5-1)

Recognition of all individuals known to be carries of hepatitis Band C would aid in knowing when special precautions were necessary. However, only about half of th people infected with hepatitis ever have clinical signs and
symptoms of the infection, “and some individuals who have completely recovered from the disease still shed intact virus particles in their secretions.

The concept of universal precautions was developed 0f  address the inability of health care providers to specically identify all patients with communicable disease The theory on which the universal precautions COIKer j based is that protection of self, staff, and patients from
contamination by using barrier techniques when trcatinc all patients as if they all had a communicable disea e ensures that everyone is protected from those who do have an infectious process.

Universal precautions typically ‘include having all doctors and staff who come in contact with patient blood or secretions, whether directly or in aerosol form, wear barrier devices, including a face mask, eye protection, and .gloves. Universal precaution procedures go on to include decontaminating or disposing of all surfaces that are exposed to patient blood, tissue, and secretions. Finally, universal precautions mandate avoidance of touching, and  thereby contaminating, surfaces (e.g., the dental record, telephone) with contaminated gloves or instruments.

BOX  5-1

Methods Designed.to Limit the Spread of Hepatitis Viruses

Methods Designed.to Limit the Spread of Hepatitis Viruses

Methods Designed.to Limit the Spread
of Hepatitis Viruses