Antimicrobial Drug Interactions in Periodontology Examined

Researchers have found that a light-detecting biosensor system can quickly and effectively determine whether antibacterial treatments are working in patients with periodontitis. The Oregon Health & Science University (OHSU) School of Dentistry research team also found that the anesthetics lidocaine and prilocaine, and the antiseptic chlorhexidine, do not interfere with the antibiotic minocycline hydro­chloride when it is used to treat periodontal disease, and that the drugs can actually complement the antimicrobial activity of such treatment. Plaque-induced periodontitis is typically treated nonsurgically by scaling and root planing. An adjunct nonsurgical therapy is the use of the antibiotic minocycline hydrochloride, which can be delivered directly into tooth pockets. The antiseptic chlorhexidine is typically used as a mouth rinse in conjunction with such antibiotic therapy. The anesthetics lidocaine and pri­locaine are often applied di­rectly to tooth pockets for numbing prior to scaling and root planing.
     The goal of the OHSU study was to use a light-generating gene for development of an oral bacteria biosensor, and then examine the effect of minocycline hydrochloride either alone or in combination with lidocaine/prilocaine or chlorhexidine. The OHSU re­search team found that mino­cycline hydrochloride produced quick and effective re­sults in treating periodontal infection. When lidocaine and prilocaine were added to the minocycline hydrochloride regimen, there was no interference with the potent anti­bacteriostatic activity of mino­cycline hydrochloride, but actually an additive antibacterial effect. The chlorhexidine rinse, in conjunction with either high or low doses of minocycline hydrochloride, also had an additive effect.
     “We were pleased at the sensitivity of the bioluminescence-generating lux gene in the bacterial transformants and its use in determining antimicrobial activity. The biosensor system also al­lowed us to rapidly monitor inhibition of bacterial metabolism, which is promising,” noted Curt Machida, PhD, principal investigator and professor of integrative biosciences and pediatric dentistry in the OHSU School of Dentistry. Dr. Machida’s lab also hosted the study.