In Vitro Fit and Cementation Resistance of Provisional Crowns for Single Implant-Supported Restorations

Abstract

This study aimed to verify marginal fit and the effect of cement film thickness standardization on retention of provisional crowns made with prefabricated acrylic cylinders on abutments, using two temporary luting agents subjected or not to mechanical cycling. Provisional crowns were made from bis-acryl (Luxatemp Fluorescence) or methyl methacrylate (Duralay) resins on acrylic cylinders and marginal fit and cement film thickness were evaluated. For retention evaluation, crowns were cemented with two temporary luting agents: non-eugenol zinc oxide (Tempbond NE) or calcium hydroxidebased (Hydcal) cements and subjected to tensile strength in a universal testing machine. After cleaning, debonded crowns were cemented again, subjected to mechanical cycling and retention was reassessed. The results of marginal fit and cement film thickness were analyzed by Student's t-test while retention of cements before and after mechanical cycling was analyzed using a mixed linear model. Methyl methacrylate crowns presented greater marginal misfit (p=0.001) and occlusal cement film thickness (p=0.003) than the bis-acryl ones. No difference was observed at axial cement film thickness (p=0.606). Resins (p=0.281) did not affect crown retention, but luting agents (p=0.029) and mechanical cycling (p=0.027) showed significant effects. The only significant interaction was mechanical cycling*luting agents, which means that luting agents were differently affected by mechanical cycling (p=0.002). In conclusion, the results showed that bisacryl resin associated to calcium-hydroxide luting agent provided the best retention and lower cement thickness.

Characterization of Bis-Acryl Composite Resins for Provisional Restorations

“…The relationship between surface roughness and color stability of dental materials was shown in previous studies (12,13). The surfaces of ST2 and PVP were significantly rougher compared with PT4, a material that showed stable optical properties in this study.…”

“…Bis-acryl composite resins may be used for virtually all types of interim restorations. In addition, according to manufacturers and a few studies in the literature, these materials may present other improved characteristics compared with PPMA, including higher abrasive resistance and esthetics, lower marginal misfit, lower free monomer elution and improved repair potential (7)(8)(9)(10)(11)(12)(13). Some materials also have the possibility of dual polymerization.…”

Tensile strenght of a dental cement based on copaíba oil-resin

“…Cementing agents can provide different levels of retention, which depends on multiple factors such as intraoral pH, occlusal forces, and temperature changes in the oral environment (MORIS et al, 2015).…”