Objectives  The aim of this study was to evaluate the plastic deformation of the hexagonal connection, and the removal torque of the implant-abutment joint of two dental implants combined with internal or external hexagonal connection implants after mechanical cycling. Materials and Methods  Twenty-four dental implants were used in the study. Half of the implants had internal hexagonal connections (IH; Titamax II Plus) and the other half had external hexagonal connections (EH; Titamax Ti Ex). Four groups of two types of dental implant abutments (titanium: Ti, UCLA II Plus and zirconia: Zr, fabricated by CAD/CAM; n = 6) were investigated. The abutments received a metallic crown and the settings were submitted to mechanical cycling (MC; 10 6 cycles, axial load, 120N). The connection surface area was measured by scanning electron microscope (SEM) images. The removal torque was evaluated and the plastic deformation of the hexagonal surface of the implant was measured by comparing the images before and after MC. Statistical Analysis  Paired- t test was used to analyze the data statistically at a significance level of α = 0.05. Results  The torque values decreased for all groups after MC, and the hexagonal surface area decreased due to plastic deformation for IH and EH associated with Zr abutments. Conclusions  Zirconia abutments showed the worst plastic deformation of the implant connection surface and torque loosening when associated with IH implant.

Objective: This study aimed to evaluate the bond strength (BS) of a ceramic coping-abutment implant interface according to the luting agent, before and after thermal cycling (TC). Methodology: Forty ceramic copings and abutments (Ti) were divided into four groups (n=10): OZ (zinc oxide eugenol free), PZ (zinc phosphate), GIC (resin modified glass ionomer), and RC (adhesive resin cement). BS test was performed using a universal testing machine before and after TC. Analysis of variance (ANOVA) and Tukey test (p<0.05) were performed for the means. Results: The results showed that before TC, the values ranged from 50.77 N (OZ) to 240.21 N (GIC). After TC, the values showed intermediate results -3.5 N (OZ) and 330.66 N (RC), 90.58 N (PZ), and 280.43 N (GIC). OZ performed the worst, both before and after TC. Before TC, GIC had the highest value. After TC, RC had the highest value of BS. Conclusions: The aging process influenced and inverted the results of the GIC and RC groups, and had a greater negative impact on the OZ group.