title: 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 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.
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, USP - University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Izabela Cristina Maurício
authors.initials: IC
authors.lastname: Moris
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, USP - University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Juliana Elias de
authors.initials: JE
authors.lastname: Oliveira
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, USP - University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Adriana Cláudia Lapria
authors.initials: AC
authors.lastname: Faria
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, USP - University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Ricardo Faria
authors.initials: RF
authors.lastname: Ribeiro
authors.affiliation: Department of Dental Materials and Prosthodontics, Dental School of Ribeirão Preto, USP - University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: Renata Cristina Silveira
authors.initials: RC
authors.lastname: Rodrigues
mesh_terms: D003442:Crowns; D019250:Dental Implants, Single-Tooth; D019094:Dental Prosthesis, Implant-Supported; D006801:Humans; D066298:In Vitro Techniques