Evaluation of retention of precision attachments for free end cases

Objective: The purpose of this work was to compare the behavoir of three extra-coronary, resilient and precision attachments: SR3.0-CNG (E1), Microfix–Odontofix (E2) e Clickfix–Odontofix (E3), submitting each one to the fatigue test and measuring the required strength for removal the RPD framework. Method: There was obtained a mettalic die and there were done 15 samples corresponding to milled crowns with the positioned attachments, that any group of five concerned to one kind of attachment. Soon after, there were obtained RPD frameworks, positioned the females and submitted to the fatigue test. For each sample, there were executed 7350 cycles simulating the use of the framework for five years, with the following periods: 0 (T0), 0.5 (T1), 1 (T2), 2 (T3), 3 (T4), 4 (T5) and 5 years (T6). Results: The results were submitted to ANOVA and Tukey test (p<0.05). According to the analysis, there was statistically significant difference regarding the required strength (N) for removal of three attachments: E2 (5.43 + 1.56) < E3 (9.64 + 3.56) < E1 (12,86 + 3,83). Regarding the required strength for removal during the time of simualtion, there was difference betwwen T0 (10,74N) and T6 (7,81N). Conclusions: It concludes that the SR3.0-CNG attachment presented the best performance in the evaluated conditions.