Avaliação do comportamento biomecânico de conexões implante-abutment cônicas internas com 11.5 e 16 graus de angulação

Abstract

The rehabilitation of toothless patients with prostheses on implants is an established treatment. However, it is still sought to understand the causes of technical complications related to the implant-abutment connection and to reduce trauma to the patient. The most common technical complications reported are loosening and screw and abutment fractures. Therefore, the evaluation of the factors that cause these complications and the clinical perception regarding the treatment are important. Thus, this thesis aimed to evaluate the influence of the simulation of masticatory loads on the maximum force supported, loosening of screws, pull-out and stress level of internal tapered implant-abutment connections with 11.5 and 16 degrees of angulation. In addition to presenting the single-unit rehabilitation of two patients with clinical follow-up of up to 24 months. Thus, the objectives of this thesis: Objective 1: To verify the influence of masticatory loads on the maximum force supported in internal tapered connections – In vitro study. This study evaluated 3 types of abutments, 1 single-body (11.5 degrees angulation) and 2 two-piece (11.5 and 16 degrees angulation). Objective 2: To evaluate the influence of masticatory loads on the loosening of screws, pull-out of two-piece abutments and stress distribution in internal tapered connections – In vitro study. This study evaluated 3 types of abutments, 1 single-body (11.5 degrees angulation) and 2 two-piece (11.5 and 16 degrees angulation). Objective 3: To report the single-unit rehabilitation of 2 cases of lower molars with immediate placement of internal tapered implants with 16 degrees of angulation and immediate provisionalization. This study reported the rehabilitation of 2 patients with single-unit prostheses on lower molars and discussed the impact of using abutments for cemented and screwed prostheses. After analyzing the study data, it could be concluded that the simulation of the masticatory loads had an influence on the maximum force supported in the 11.5 degrees implant connections but did not influence the 16 degrees connections. The loosening of screws of the tested connections and the pull-out of the two-piece abutments were influenced by masticatory loads. The connection of implants with 16 degrees showed a better stress distribution. The immediate placement of 16 degrees internal tapered implants and immediate provisionalization with cemented or screwed prosthesis proved to be successful protocols for the treatment of single-unit rehabilitation, being able to minimize bone and tissue remodeling. Therefore, the correct selection of prosthetic abutments is also a fundamental step in predicting the case.