ANN ARBOR—U.S. dentists have all but won the war against cavities but another enemy?periodontal disease?continues to attack about 10 percent of U.S. adults, ravaging gums and bones, and threatening tooth loss. According to the University of Michigan School of Dentistry, however, there is now the possibility that most forms of periodontal disease can be effectively treated with antimicrobial drugs.

A series of studies conducted by Walter J. Loesche, U-M professor of dentistry and microbiology, and colleagues at the University of Detroit School of Dentistry have shown that nearly seven out of 10 apparently “hopeless” teeth can be saved from extraction?and nine out of 10 teeth slated for periodontal surgery can be saved from the scalpel?when the gums are treated with an antimicrobial medication after debridement. Debridement, the standard periodontal treatment, entails scaling out pockets of infection under the gums and planing down infected roots.

“The gums of about 90 percent of periodontal patients are infected with anaerobic bacteria, including spirochetes, that inflame the tissue and weaken the bone,” Loesche explained. “The antimicrobial medications reduce the numbers of spirochetes and other anaerobic bacteria and allow the gums and bone to heal. Overall, 81 percent of the patients in our current study who received the debridement and an antimicrobial medication did not need the initially recommended surgery or extractions.”

The U-M study appears in the May issue of the dental journal, Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics. In the study of 90 patients, Loesche and his colleagues tested several drugs, including an antimicrobial, metronidazole SIGH-clean] and chlorhexidine [clor-HEX-i-dine]. Others received a placebo. The three drugs have not been used typically to treat periodontal disease. Metronidazole and the placebo were taken orally or delivered locally by inserting ethyl cellulose film containing the medication between the gums and teeth. Doxycycline was taken orally and the chlorhexidine was delivered locally in the film. The 90 patients could receive up to five rounds of treatment- know which patients had received which treatment evaluated the condition of the patients’ teeth and gums at baseline?before treatments began?and after each round of treatment. At baseline, 783 teeth in total were earmarked for either periodontal surgery or extraction. By the end treatment, only 12 percent?93 of the teeth?were still in need of either surgery or extraction.

“Overall, there was an average 93 percent reduction in the need for periodontal surgery and a 67 percent reduction in tooth extraction,” Loesche said. Both metronidazole and doxycycline, taken orally, were equally effective. Thirty-nine percent of the patients needed only one round of oral medication. Another 42 percent ultimately responded after retreatment with either oral or local medications. The comparative effectiveness of metronidazole and chlorhexidine delivered locally was indeterminate and requires more study.

The U-M study was funded by a grant from the National Institute for Dental Research. Loesche’s colleagues were M. Antony Schork, U-M professor of biostatistics; James Giordoan, Stephen Soehren, Rowland Hutchinson, Charles F. Rau, all professors of dentistry at U-D; and Lynne Walsh, U-D registered dental hygienist.

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