Análise de componentes protéticos conceito switching : conformidade de adaptação e teste mecânico de fadiga

Abstract

The aim of this study was to analyze both the adaptation conformity of switching platform prosthetic components and their behavior in fatigue mechanical tests. The subject was split into two manuscripts according to the scope of two specific journals in the area of oral rehabilitation. The manuscript 1 presents a literature review that enlightened concepts related to the usage of the switching platform and its biological benefits demonstrated in the literature. However, factors associated with the biomechanical stability provided by this new concept have shown to be a coarsely explored area by science. Thus, such factors need to be better understood and confirmed by studies evaluating biomechanical issues of this platform. After demonstrating this shortage in the literature review, a laboratory study started, aiming at responding questions linked to the long term prosthetic stability. The manuscript 2 assessed the adaptation conformity of switching components confronted to mechanical cycling tests. The methodology was based on 40 prosthetic components for unity rehabilitations on implants standard HE 4.1 RP, being divided in four groups: 10 components UCLA 4.1 mm (group UC 4.1), 10 components UCLA 3.6 mm (group UC 3.6) , 10 components type conic abutment 4.1 mm (group AC 4.1) and 10 conic abutment 3.6 mm (group AC 3.6) on the respective implant standard RP HE 4.1 mm. The groups have been evaluated by Energy Dispersive Spectroscopy (EDS) to confirm the manufacture standard of the samples. Scanning electronic microscopy (SEM) was used to evaluate the adaptation in the vertical (FV) and horizontal (DH) directions. For the statistical analysis of the FV data, Kruskal-wallis and Crosstabs were used. One-way analysis of variance (ANOVA) and Tukey (5%) were used for the DH data. The four groups of components (UC 4.1, UC 3.6, AC 4.1, AC 3.6 ) were prepared according to the ISO 14801: 2007 standard and submitted to 1,000,000 cycles, with a load of 100 N and frequency of 1 Hz in a universal fatigue testing machine. Results indicated conformity of adaptation (FV) among components varying from 70% to 90%. Concerning DH, the two groups of switching components (UC 3.6 and AC 3.6) presented a negative gap of 7.07% and 5.36% respectively in relation to the regular platform, while the RP groups (UC 4.1 and AC 4.1) presented a negative gap of 1.21% and 0% (p≤0.05). The loss of torque after the cycling test were: 25% (UC 4.1), 39% (UC 3.6), 38% (AC 4.1) and 51% (AC 3.6), (p≤ 0.01). Hence, the result of the present study indicate that the switching platform components present a favorable short-term biological behavior according to the literature, but limited biomechanical behavior. In adaptation factor, there is a strong degree of precision in almost all samples in terms of FV. DH is noticed in all groups. It is also noticeable that in the platform switching groups the loss of torque after mechanical cycling test was larger.