Annual examination of patients with dental implants sometimes reveals infections in the areas surrounding the implants, physiologic and pathologic resorption of supporting bone structures, and disturbance and fracture of the implant dentures. These conditions are suspected to be the result of the involvement, direct or indirect, of bacteria inhibiting dental plaque. Therefore how to reduce the number of microbes is an important factor in the prevention of these conditions. Citric acid could be utilized to get the microflora under control. After collecting masses of bacteria from implant, the effect of gingival sulci and citric acid in the growth of bacteria was compared with that of minocycline hydrochloride of ointment.
Materials and Methods: A total of 50 former patients ―20 with endosseous implants, 5 with endodontic endosseous implants and another 25 with periodontal disease― were enrolled in this study. Masses of bacteria garnered from the implant gingival sulci and periodontal pockets were cultivated by an anaerobic culture and 50 select germ stocks were obtained. By a disk method, the effects of citric acid (pH 1.0) and minocycline hydrochloride of ointment were examined to see which of the reagents more effectively inhibit the growth of bacteria. We also checked the sensitivity of bacteria before and after letting stand for three minutes. Furthermore, titanium test pieces were soaked in a citric acid solution (pH 1.0) for one hour to examine the extent to which bacteria adhered to the titanium test pieces with scanning electron microscope.
Results: Hardly any significant difference was noted in the sensitivity of bacteria to citric acid and minocycline hydrochloride of ointment, except for some strains. The sensitivity of adherent bacteria was also examined three minutes after implant gingival sulci were treated with citric acid. The result showed no difference in sensitivity between citric acid and minocycline hydrochloride of ointmeat. On the surface of titanium treated with citric acid, it was clear that adherance of bacteria was prohibited.