Influência da conicidade do pilar e tipo de agente cimentante na retentividade de coroas metálicas cimentadas sobre pilares personalizáveis de implantes

Abstract

Several factors must be considered in the selection of angled abutments. In these situations, the clinician should find a practical way to overcome the lack of retention. The purpose of this study was to evaluate the bond strength of metallic crowns cemented to straight and angled customizable abutments with different definitive luting agents. Ninety one regular external hex analogs and abutments were divided in Control group (C): customizable straight abutment cemented with zinc phosphate (n = 10); three groups (n = 10) with 17° angled abutment cemented with zinc phosphate (A17ZP), Panavia F (A17RM) and RelyX U100 (A17R) cements and more three groups (n = 10) with 30° angled abutment also cemented with zinc phosphate (A30ZP), Panavia F (A30RM) and RelyX U100 (A30R) cements. The metal copings were cemented onto their corresponding metal dies and crowns cemented with Panavia F were pre-treated with an alloy primer containing an acid-phosphated monomer (MDP). Data from the all groups were compared to control group with a 1-way ANOVA (α=.05) and Dunnet s test, and comparison between tested groups were done with 2-way ANOVA (α=.05) and Tukey s test. SEM and CLSM evaluation were performed (n = 3) aiming to investigate microscopic features of the abutment-cement-crown interfaces. The mean force (SD) required to dislodge the crowns in the C, A17ZP, A17RM, A17R, A30ZP, A30RM and A30R groups was 357,26 (62,21) N; 251,50 (20,13) N; 397,05 (88,48) N; 328,71 (79,87) N; 276,70 (17,96) N; 377,81 (90,61) N and 335,42 (88,34) N respectively. Panavia F presented the higher tensile bond strength results and zinc phosphate the lower between the tested groups. Only A17ZP group was different from control group (p=.007) and the abutment taper has no influence in retentive values. Zinc phosphate showed an inhomogeneous cement line in SEM and CLSM analysis. The presence of MDP primer could be perceived in CLSM images of Panavia F group. Within the limitations of this in vitro study, the Panavia F presented the higher bonding strength between tested groups, however, all 3 cements tested were similar to control group except A17ZP group, showing that in the conditions of the study they all can be successfully used.