The effect of cycle loading and thermocycling on the retention of ball and locator attachments

Abstract

Introduction : Implant retained overdentures have extra advantages when compared to conventional dentures. At present, numerous types of attachments have been designed to provide adequate retention under long-term function, easy to use and maintenance. The ultimate choice of attachment type should be based on the properties and factors that influenced the retention of the attachment. Objectives : To examine the effect of cyclic loading on the retention of yellow clix insert ball and pink Locator attachments and to investigate the effect of thermocycling and type of attachments on the retention. Methods : Cyclic loading test: 2 implants retained overdenture with ball and Locator attachments (n=6) were subjected to 5 consecutive pulls before and after 100,000, 200,000, 500,000, 700,000 and 1,000,000 cyclic loading cycles, at 50N, 2Hz. Thermocycling test: ball and Locator attachments(n=10) were subjected to 5 consecutive pulls before and after 5,000 and 10,000 cycles of thermocycling. The retention values were averaged and statistically analyzed by 2-way repeated measures ANOVA and Tukey HSD tests at p<0.05. Results : Retention of pink Locator attachments was higher than yellow clix insert ball attachments before and after cyclic loading and thermocycling. The retention of yellow clix insert ball attachments significantly decreased at 700,000 and 1,000,000 cyclic loading cycles. The retention of pink Locator attachments significantly decreased at 100,000 and 1,000,000 cyclic loading cycles. Yellow clix insert ball attachments were not significantly affected by thermocycling. And the retention of pink Locator attachments significantly increased after 5,000 thermocycling cycles. Conclusions : The retention of both attachments decreased after cyclic loading. Yellow clix insert ball and pink Locator attachments were not susceptible to retention loss from thermocycling.