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

Izabela Cristina Maurício Moris,Adriana Cláudia Lapria Faria,Juliana Elias De Oliveira,Ricardo Faria Ribeiro,Renata Cristina Silveira Rodrigues

doi:10.1590/0103-6440201300289

Izabela Cristina Maurício Moris, Adriana Cláudia Lapria Faria + Show 3 more

Open Access

https://doi.org/10.1590/0103-6440201300289

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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 hydroxide-based (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 bis-acryl resin associated to calcium-hydroxide luting agent provided the best retention and lower cement thickness.

Highlights

It is claimed that difficulties related to the use of temporary removable partial dentures or adhesive prosthesis forced the development of techniques aiming to decrease healing period, simplifying the procedure, decreasing the costs and offering comfort for the patients
The aim of this study was to evaluate the effect of two materials used for provisional prostheses on marginal fit and cement film thickness at abutment-cylinder interface when prefabricated cylinders are used for provisional crown construction, and the effect of two temporary luting agents and mechanical cycling on the retention of these crowns
The retention measured by tensile strength values (Table 3) and its statistical comparison (Table 4) demonstrated that retention was affected by temporary luting agents and mechanical cycling, but the resins did not interfere with retention

Summary

Introduction

It is claimed that difficulties related to the use of temporary removable partial dentures or adhesive prosthesis forced the development of techniques aiming to decrease healing period, simplifying the procedure, decreasing the costs and offering comfort for the patients. Based on this fact, immediate loading implants were proposed for provisional prosthesis installation immediately after implant placement, restoring esthetics and function to the patients [1]. Multiple factors in oral environment such as temperature change, pH and occlusal forces affect properties and retention of provisional luting agents [6]. Several studies reported the use of non-eugenol zinc oxide and calcium hydroxidebased luting agents in the clinical practice for temporary cementation of implant-supported crowns [7,8,9,10,11]

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