Amoxicillin Use During Infancy May Be Linked To Tooth Enamel Defects

Dental fluorosis, a result of exposure to excessive fluoride duringenamel formation, is one of the most common developmental enameldefects, according to background information in the article. Theclinical signs range from barely noticeable white flecks, to pits andbrown stains. Amoxicillin is one of the most common antibiotics usedamong pediatric patients, mainly for treatment of otitismedia--infection and inflammation of the middle ear. There has beensome evidence that amoxicillin use could be associated with dentalenamel defects, and, the authors suggest, even a small effect on dentalenamel could have a significant effect on the public's dental healthbecause of the widespread use of amoxicillin.

Liang Hong, D.D.S., M.S., Ph.D., of the University of Iowa, Iowa City,and colleagues assessed the association between dental fluorosis andamoxicillin use during early childhood. (Dr. Hong is now with theDepartment of Dental Public Health and Behavioral Science, Universityof Missouri – Kansas City.) The researchers analyzed data from the IowaFluoride Study, a prospective study investigating fluoride exposures,biological and behavioral factors, and children's dental health. Theyfollowed 579 participants from birth to 32 months, using questionnairesevery three to four months to gather information on fluoride intake andamoxicillin use.

"The results show that amoxicillin use during early infancyseems to be linked to dental fluorosis on both permanent first molarsand maxillary central incisors," the authors report. "Duration ofamoxicillin use was related to the number of early-erupting permanentteeth with fluorosis."

By the age of one year, three-quarters of the subjects had usedamoxicillin. By 32 months, 91 percent of participants had usedamoxicillin. "Overall, 24 percent had fluorosis on both maxillarycentral incisors," the authors write.

Amoxicillin use from three to six months doubled the risk of dentalfluorosis. "The significantly elevated risk for dental fluorosisassociated with amoxicillin use during early infancy was found at alllevels of statistical analyses, even after controlling for otherpotential risk factors, such as fluoride intake, otitis mediainfections, and breastfeeding," the authors report.

The authors emphasize that additional laboratory and clinicalstudies--including controlled animal studies with specified amoxicillindosages, chemical analysis and histological examination of affectedteeth, and additional well-designed epidemiological studies--are neededto confirm the results.

"The findings suggest that amoxicillin use in infancy could carry someheretofore undocumented risk to the developing teeth," they conclude."While the results of this one study do not warrant recommendations tocease use of amoxicillin early in life, they do further highlight theneed to use antibiotics judiciously, particularly during infancy."

(Arch Pediatr Adolesc Med. 2005;159:943-948. Available pre-embargo to the media at www.jamamedia.org.)

Editor's Note: This study was sponsored by grants from the National Institutes of Health, Bethesda, Md.

Editorial: Amoxicillin and Fluorosis
Too Soon to Cap the Medicine Bottle?

In an editorial accompanying the article, Paul S. Casamassimo, D.D.S.,M.S., of the Ohio State University College of Dentistry and ColumbusChildren's Hospital, writes that pediatricians have already reducedtheir use of amoxicillin to treat ear infections. "Looking back throughdecades on the repeated dental cautions about tetracycline, it tookyears and alternative drug choices to reshape clinical practice toreduce what was a far more obvious, generalized, and moredifficult-to-treat cosmetic problem. If the choice is hearing loss andits sequelae or the possible risk of minor cosmetic disappointment,there is little doubt of what will happen. Frankly, at this point, theassociation between amoxicillin use and fluorosis needs further study,as Hong et al have suggested. … Until that time, the best course ofaction may be what both the medical and dental communities haveadvocated for a long time--careful, thoughtful, and appropriate use ofboth fluoride and antibiotics."

(Arch Pediatr Adolesc Med. 2005;159:995-996. Available pre-embargo to the media at www.jamamedia.org.)