Evaluación in vitro de resistencia al volcamiento en preparaciones con altura ocluso – cervical insuficiente elaborando cajuelas proximales y axiales para coronas maquinadas

Abstract

Objective: To determine the resistance to crown overturning in preparations that do not meet the required occlusal-cervical height of 4 mm by performing the trunks on proximal and axial walls Materials and methods: 100 steel blocks divided into 5 groups were evaluated, with characteristics of a lower molar tooth preparation with occlusal - cervical height of 3mm, convergence of 10 ° and chanfer with rounded internal angle, with axial and proximal 2mm and 3mm wide. A lower molar was waxed, and the cobalt chromium copings were made with the PHIBO sintering system. The strength of each sample was evaluated by applying oblique forces at 45 degree angulation, measured by the SHIMADZU universal machine. Statistical analysis between the groups evaluated was compared using the Kruskal-Wallis test with a p-value of <0.001, which had a statistically significant difference. Results: The 3mm wide trunk has the lowest average with 15058.91, and the best results are obtained with 2mm and 3mm wide axial trunks with the highest average of 18070.94 and 16572.97; since they presented greater resistance and there was no statistically significant difference. Conclusion: It was verified that the axial bolsters increase the resistance to the eviction of the crowns before the application of oblique forces.