SOFT-TISSUE RESPONSE TO PLAQUE-FORMATION AT DIFFERENT IMPLANT SYSTEMS- A COMPARATIVE-STUDY IN THE DOG

The aim of the present experiment was to study the location and compos ition of plaque associated lesions in the mucosa adjacent to implant s ystems that differed with respect to both geometry and dimension. At d ay 0 extraction of the mandibular premolars were performed. After a he aling period of 3 months, fixtures of the Astra Tech Implants, Dental System(R), the Branemark System(R) and the ITI Dental Implant System(R ) were installed. In each mandibular quadrant 1 fixture of each implan t system was installed in a randomized order. A period of plaque contr ol was initiated. Following another 3 months of healing, abutment conn ection was performed in the 2-stage systems (the Astra Tech Implants, Dental System(R) and the Branemark System(R)). After 1 month, the plaq ue control measures were abandoned and plaque formation was allowed fo r 5 months. The animals were killed and biopsies representing each imp lant region obtained. The tissue samples were prepared for light micro scopy and exposed to histometric and morphometric measurements. The pr esent study demonstrated that plaque formation resulted in the establi shment of an ICT lateral to a pocket epithelium. The lesion was found to be similar regarding extension and composition in the peri-implant mucosa of the 3 implant systems tested. The vertical extension of the ICT was in all systems within 91-99% of the vertical dimension of the junctional epithelium. The marginal bone level, measured from the abut ment/fixture (PS) border, did not differ between the three systems.