Evaluation of peri-implant soft and hard tissues behavior in screw-retained crowns by the biologically oriented preparation technique (BOPT): Ambispective longitudinal analytical study

BACKGROUND: Clinical and radiographic evaluation of soft and hard tissues around convergent collar implants and shoulderless abutments. MATERIAL AND METHODS: Ambispective longitudinal analytical study with a sample size of 32 implants in 21 patients treated in a private dental clinic. Patients were divided into two groups: Prama Implants or group 1 (n=21) and Shelta implants combined with XA abutment or group 2 (n=11). Probing depth, horizontal mucosa thickness, peri-implant bone loss, plaque and bleeding after one-and two-year follow up are analyzed. RESULTS: In group 1, mean probing depth value was 1.67 mm (±0.58) and mean horizontal mucosa thickness value was 2.71 (±0.96). In group 2 mean probing depth was 2.18 (±0.40) and mean horizontal mucosa thickness value was 3.27 mm (±1.19). In group 1 an 85.7% of peri-implant bone level was maintained and a 14.3% increased. In group 2 a 100% of peri-implant bone level was maintained. In group 1 a 19% presented plaque when crowns were removed and in group 2 a 18.2% presented plaque. Neither of two groups presented spontaneous bleeding when crowns were removed. A 52.4% presented probing bleeding in group 1 and a 45.4% in group 2. CONCLUSIONS: Biologically guided crowns design seems to provide peri-implant hard and soft tissue stability. Key words:Biologic width, peri-implant soft tissue, marginal bone loss, transmucosal implant, convergent collar, BOPT (biological oriented preparation technique), BOPT abutment, soft tissue stability.