CLINICAL PROBING AND RADIOGRAPHIC ASSESSMENT IN RELATION TO THE HISTOLOGIC BONE LEVEL AT ORAL IMPLANTS IN MONKEYS

Clinical probing level and radiographic bone level were compared to hi stologic bone level around screw type oral implants in 4 monkeys (Maca ca Fascicularis). Two implants in each monkey retained a fixed partial prosthesis in supra-occlusal contact with an antagonizing splint. The se implants were brushed 1 x a week and subgingival cleaning was perfo rmed 1 x a month. Unloaded implants in the same monkeys were never cle aned and, additionally, a cotton cord was placed around these to promo te plaque accumulation. After 18 months, intraoral radiographs of the implants were obtained and probing levels were recorded with a metal p robe using a standardized force of 0.2 N (Vivacare TPS Probe) and agai n using a moderate, unstandardized pressure. Immediately afterwards th e animals were sacrificed. Sections, approximately 50 mu m thick, of t he implants and surrounding tissue were cut. The average probing level s with unstandardized pressure were 1.1 mm and 3.9 mm coronal to the h istologic bone levels for implants with plaque accumulation or excessi ve occlusal load, respectively. With standardized probing force, the d ifference between the probing levels and histologic bone levels were e ven larger. The radiographic bone levels were on average only 0.5 mm a nd 0.1 mm short of the histologic bone levels for the two groups of im plants. Only the radiographic bone level revealed a statistically sign ificant correlation with the histologic assessment.