Impact of gastric acid on mechanical properties, structural and microbiological implant supported prosthesis manufactured by new monolithic ceramic materials simulating mastication

Abstract

Recently, the causes and effects of acid erosion caused by gastric acid on ceramic restorations have become a topic of great interest in dentistry worldwide. Therefore, the general objective of the present study will be to evaluate the structural, mechanical and microbiological properties of 04 monolithic ceramic materials after acid erosion and mechanical cycling. Through 02 studies/phases, in Study 1, 180 specimens will be made per group in the form of a bar (17×4×2.0mm) to evaluate the structural properties (Surface roughness (Ra), atomic force microscopy ( MFA) and scanning electron microscopy (SEM)), mechanical (flexural strength (Rf), modulus of elasticity (ME) and Vickers hardness (HV)) and microbiological (quantification of cultivable cells (CFU) of the mixed biofilm of S. Mutans and C. Albicans and analysis of the biofilm structure using SEM) and in Study 2 in the shape of single crowns implant-supported crowns on morse taper implants (4 x 11.5 mm) with "TiBase" intermediates in order to characterize the surface (Ra and SEM), mechanical (fatigue and fracture resistance) and microbiological (CFU and SEM) properties of 04 monolithic ceramics (lithium disilicate - IPS e.max CAD; nanoceramic - Cerasmart; polymer-infiltrated ceramics - Enamic and silicate zirconia-reinforced lithium - Celtra Duo) after erosive challenge (D.E.) (immersion in HCL pH=2 for 455 hours) associated with mechanical cycling (C.M.) (150 N x 1.2x106) at a frequency of 2Hz, at 37ºC. In study 1 and study 2 (only for surface characterization), the analyzes will be performed at 3 different times, namely: T1 - after 24 hours in distilled water (initial), T2 - after DE and T3 - after DE + CM , for study 2, will be evaluated after DE + CM. The quantitative data obtained in each analysis will be submitted to the normality test and later to the most appropriate statistical test, with a significance level of 5%. The results of SEM and MFA will be analyzed qualitatively.