clinieal judgment and management decisions clearly falls to the dentist, and thedentist must include tfie patient in the informed consent process by making thepatient aware of the treatment options. If, m the dentist's judgment, improperrecommendations have been received from a physician who is unfamiliar withthe guidelines, the dentist should proceed without antibiotic prophylaxis. When-ever antibiotic prophylaxis is utilized, the perceived benefits must be weighedagainst the known risks, including occurrence of allergic reactions, excessivetreatment costs, and development of microbial resistance. The dentist whoblindly follows a physician's erroneous recommendation will not be able todefend those actions if harm befalls the patient from improper prescribing ofantibiotics.

Little et al have summarized the findings for patients with other implanteddevices who undergo dental treatment (Dental Management of the MedicallyCompromised Patient, Mosby, 1997) There is no clear rationale for the use ofantibiotic prophylaxis in dental patients who have received artificial finger joints,penile or breast implants, and the like If antibiotics are used, the use should beaccompanied by thorough documentation m the patient's records on the ratio-nale for such usage.

In summary, two quotations from the past seem appropriate. John Taylor(1694-1761) was quoted saying, "A doctor is a man who writes prescriptionsuntil the patient either dies or is cured by nature," Voltaire 11694-1778) onceremarked, "Doctors ... prescnbe medicine of which they know little to cure dis-eases of which they know less, in human beings of which they know nothing."In the intervening 220 years, some things have not changed. The use of prophy-lactic antibiotics should not be predicated on ignorance or fear of litigation but onsound scientific principles and a working knowledge of pharmacotherapeutics.The time has arrived for dentists to shed the cloud of uncertainty and doubt andto restrict the use of prophylactic antibiotics only to those defined patients whoclearly have a benefit potential that outweighs the risk factors. Recent additionsto the literature from organized groups have provided the tools necessary toachieve those goals, but these tools are of value only if used by practitioners.

PERIODONTICINDICATIONS

THOMAS J. PALLASCH, DDS, MS

Antibiotics are employed in penodontal therapy in one of three situations: (1) themanagement of acute periodontal conditions, primarily periodontal abscessesusually in conjunction with incision and drainage, (21 as "prophylaxis" to "pre-vent" posttreatment infectious sequeilae, and 13) as definitive or adjunctive thera-py in the management of chronic periodontitis. The treatment protocol for acuteperiodontal conditions is well established, little if any data support the use ofantibiotics to prevent dental treatment sequeilae (other than endocarditis), and theuse of antimicrobials to manage chrome periodontitis is both controversial andmisunderstood.

Acute periodontal conditions (abscesses, necrotizing gingivitis) do not differsubstantially from other acute orofacial infections, and their antibiotic manage-ment IS similar: high antibiotic blood levels for as short a period of time as possi-ble (until remission of infection), which will reduce the possibility of microbialresistance development. The usual package insert doses are adequate with theexception that a loading dose (2 to 4 times the maintenance dose depending onthe severity of the infection) should be employed to achieve high blood levelsrapidly because acute orofacial infections tend to have a very rapid onset. Withouta loading dose, it may take 6 to 12 hours to achieve therapeutic tissue levels withmany antibiotics. Amoxicillin is exceptional because an oral dose is very rapidlyand completely absorbed, achieving blood levels 2 to 3 times greater than a com-parable dose of penicillin V. When indicated, amoxicitlin then becomes a drug ofchoice, utilizing an appropriate loading dose for acute infections.

The use of antibiotics as prophylaxis to prevent infectious sequeilae to routinedental treatment procedures is unfortunately still advocated in some quarters

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Or Pallasch is Professor of Pharmacology andPeriodontics at Ifie Uniuersity of Southern Cali-fornia, School of Dentistry, m Los Angeles, Cali-fornia 90089-0641. He was m private practice ofperiodontics in Burhank, California. Dr Pallaschis Co-Cfiair fortfie ADA—American Acaderny ofOrtfiopaedic Surgeons Committee on AntibioticPropfiylams for Dental Patients mith ProsLheticJoints and is co-author of the new AmericanHeart Association Endocarditis ProphylaxisGuidelines Reprints of these guidelines areavailable from this author

under the misconception that such a practice is effective and, if not effective med-ically, at least will prevent litigation Neither of these premises is likely to be true.The dental literature generally does not support the contention that antibioticsafter dental procedures prevent surgical infections or even sequellae such as pain,edema, and trismus The American Dental Association Council on Scientific Affairshas recently advised that antibiotics are properly employed only for the manage-ment of acute infectious disease or in the prevention of metastatic infections [pri-marily bacterial endocarditis) in medically high-risk patients U Am Dent Asscc,1997). Antibiotics given orally generally do not work quickly and without a loadingdose are unlikely to rapidly achieve high tissue concentrations; therefore their ben-efit after a procedure is doubtful. An exception is in endocarditis prophylaxiswhere unanticipated bleeding occurs in a nonpremedicated patient (see 1997American Heart Association recommendations). One of the principles of antibioticprophylaxis, established more than 30 years ago, is that the antibiotic should be mthe blood and tissues prior to the procedure.

Surgical antibiotic prophylaxis has been used successfully perioperatively(begun 1 to 2 hours before the procedure and discontinued shortly after thesurgery is completed) m the prevention of infection in certain hospital, microbiailyclean surgical procedures (cardiovascular, neurologic, orthopedic) where the infec-tion rate is low but associated with high morbidity. The hypothesis that such a pro-tocol might be of benefit m highly contaminated oral surgical procedures has neverbeen tested. Surgical prophylaxis is only indicated 111 to prevent contamination ofa sterile area, 12) where infection is unlikely but is associated with major morbidity,13) in surgical procedures with high infection rates, and 14) during implantation ofprosthetic devices IPaluzzi RG, Med Clin North Am, 1993) Dental treatment pro-cedures fit none of these categories except possibly the fourth.

The use of antimicrobials to treat dental plaque and/or periodontal disease isnothing new. Its first scientific application occurred in the 17th century whenAnton Van Leeuwenhoek, shortly after he discovered the microscope, applied salt,wine, and vinegar to "animicules" (spirochetes, bacilli, cocci) derived from "scrap-pings of teeth." Subsequent chemotherapy included hydrochloric, sulfuric, lactic,and trichloroacetic acids, silver nitrate, aspirin, zinc chloride, and hydrogen perox-ide on to "modern" therapy with antibiotics, chiorhexidine, dextranase, iodine, andeven aloe vera.

The difficulties associated with periodontal chemotherapy have included devel-oping methods to ensure a high concentration of the antimicrobial in the affectedsite for a sufficient period of t ime, the substantial variation m penodontalpathogens from patient to patient, intraoral site to site, and time to time at thesame site, and the adverse effects of antibiotics on the body's microbial ficraNow the most significant present and future difficulty with the antibiotic treatmentof periodontitis is the eventual development and dissemination of antimicrobialresistance

Little attention has been paid to an obscure report in 1996 of two bacterialisolates of vancomycin-methicillin-resistant Staphylococcus aureus in El Salvador(Navarro Mann JE, Int J Antimicrob Agents, 1996) A recent press reportdescribed another isolate in Japan. Presently vancomycin is the only antibiotice f fec t i ve against many hospi ta l s taphy lococc i and, if vancomycin-methicillin-resistant S aureus becomes epidemic and then endemic, thousandswill die annually. From virtual universal sensitivity to penicillin only a few yearsago, penicillin-resistant Streptococcus pneumontae are now globally estimated tobe 25% to 60% of isolates (Rahal K et al. Clin Infect Dis, 1997). Vancomycinresistance has appeared in up to 13% of hospital isolates of enterococci, andpresently intermediate to high resistance to penicillins occurs in 13% to 49% ofviridans streptococci in US hospitals (Doern GV et al, Ant imicrob AgentsChemother, 1996). It is likely that annually 60,000 patients in US hospitals diedirectly from nosocomial (hospital-acquired) infections (Edmund M and WenzelR. Principles and Practice of Infectious Diseases, ed 4. Churchill Livingstone,19951; the actual total may be considerably higher.

Resistance of Hehcobacter pytori to metronidazole is increasing alarmingly, andtetracycline in the gastrointestinal tract induces bacteria to transfer the genes for

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It may be imprudentto massively applyantibiotics useful in

life-threateningdiseases to a

non-life-threateningproblem.

multiple antibiotic resistance 100 to 1,000 times faster than if tetracycline werenot present (Speer 8S et al. Clin Microbiol Rev, 1992) It is strongly suspected thatS pneumomae ar\d viridans streptococci have shared the genes for penicillin resis-tance as they coinhabit the pharynx. It is also likely that enterococci received thegene for ß-lactamase production from staphylococci and that, in hospitals at least,both coinhabit the skin. It is likely only a matter of time until the vancomycin resis-tance gene passes from enterococci to staphylococci

Given the above considerations, it is reasonable to question whether periodon-tal disease is of sufficient health importance to merit systemic antimicrobial thera-py that, when applied to millions of persons, may substantially add to the globalproblems of microbial resistance to antibiotics It may be imprudent to massivelyapply antibiotics useful in life-threatening diseases to a non-life-threatemngproblem (particularly one that is so amenable to mechanical therapyl. Possibly theuse of amoxicillin-clavulanate has contributed to the altered penicillin-bindingprotein resistance seen in pneumococci and streptococci, rendering themresistant to amoNicillin-clavulanate. Widespread use of metronidazole mayeliminate its use against H pylon, which is both ulcerogenic and carcinogenicIgastric cancer). Induction of microbial resistance via tetracycline may greatlyamplify resistance not only to itself but also via the transfer of multiple antibiotic-resistant genes from resistant bacteria to susceptible bacteria.

These are very serious concerns because antibiotics are unique in that they notonly affect the host recipient but also potentially all humans through their alte-ration of the global microbial ecology. It is imperative that health care practitionersrealize that each day millions of practitioners contribute to the millions ot defineddaily doses {amount of antibiotic used daily per person) employed in the world thatplace enormous selective pressure on microbes to mutate to or acquire the genesfor microbial resistance

Therefore antibiotics, particularly systemic, in the management of periodontitismust be used with great care and selectivity Whenever possible they should bechosen based on proper culture and sensitivity tests to determine not only thepotential microbial pathogenfsl but also the antibiotic(sl most effective againstthem. Microbial sensitivity to antibiotics is highly individual and variable dependingon local geographic patterns of antibiotic use. Systemic antibiotic therapy shouldbe reserved for the 5% to 10% or less of periodontitis patients who have rapidlyprogressive and/or refractory periodontitis in which mechanical therapy has beeninsufficient to place the disease in remission.

If the antibiotic therapy of periodontitis is limited m application using the aboveprinciples, we will follow the dictum of IHippocrates to "do no harm" and likelybenefit that small group of periodontitis patients in which classically effectivemechanical therapy is insufficient.

ENDODONTICINDICATIONSJOHN W, HARRISON, BS , DMD, MS

In endodontic treatment, antibiotics are indicated for two reasons, prophylacticcoverage of patients susceptible to bacteremias and therapeutic use in patientswith infections of endodontic etiology The prophylactic use is confined topatients with certain cardiovascular diseases and disorders or compromised hostdefense mechanisms (immunocompromised patients) These patients cannottolerate bacteremias and require antibiotic coverage to protect them from life-threatening infections that may result from certain invasive dental procedures.The diseases and disorders requiring prophylactic antibiotic coverage are well-documented and require no further discussion in this limited space. It is the ther-apeutic use of antibiotics that presents the greatest challenge to the practitioner.

Therapeutic use of antibiotics in endodontics. Evidence suggests thatmany dentists are confused about the indications for therapeutic use of antibi-otics for endodontic infections (ie, odontogenic infections that involve the pulpand spread into the periradicular tissues and sometimes beyond). Recent sur-veys ¡Whitten BH et al, J Am Dent Assoc, 1996: Svec TA et al, J Dent Educ,1996) indicate that dentists often prescribe antibiotics for dental pain alone.

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