Nível ósseo marginal perimplantar

Abstract

Peri-implant marginal bone loss, present in most dental implants in function, can play an important role to achieve aesthetics and longevity on treatments. The disconnections and reconnections of abutments and the thickness of the alveolar mucosa are factors that may influence peri-implant marginal bone loss. Chapter 1 consists on a randomized clinical trial that aims to evaluate the influence of abutments disconnections and reconnections on marginal bone loss. Twenty-four participants received single implants and were randomized into two groups according to the proposed intervention: definitive abutment group (DEF), in which the abutments were definitively connected during the implant surgery; and as a control, healing abutment group (HEA), in which the healing abutments were disconnected and reconnected three times, 8, 10 and 12 weeks after the implant surgery according to conventional procedures. The radiographs were taken at predetermined periods in order to compare the perimplantar bone level between the groups. At the end of two years, the cumulated bone loss was -0.61 ± 0.10 mm and -0.81 ± 0.15 mm for groups DEF and HEA respectively, with no statistical difference between the groups. The protocol with three disconnections of the healing abutments did not significantly increase the bone loss compared to the definitive connection of the abutments. However, the connection of divergent abutments seems to exert a significant influence on marginal bone loss. Within the same study, Chapter 2 compares measurements of alveolar mucosal thickness obtained by clinical and tomographic methods in edentulous areas. Twenty-six patients with twenty-eight sites had the thickness of alveolar ridge mucosa measured by two methods: clinical, with transsurgical measurement; and by imaging, with conical beam computed tomography (CBCT). Twenty-five out of the twenty-eight CBCTs (89.29%) were considered viable for the measurements. The comparison between the two methods showed a positive correlation, with an intraclass correlation coefficient of 0.83. The CBCTs allowed visualization in most cases, with high agreement between the CBCTs and the clinical measures.