COMPARATIVE-STUDY OF 2 PRECISION OVERDENTURE ATTACHMENT DESIGNS

In this study two precision overdenture attachment designs were tested for retention-a nylon overdenture cap system and a new cap and keeper system, The new cap and keeper system was designed to reduce the time involved in replacing a cap worn by the conditions of the oral enviro nment, Six groups were tested at two different angles and retentive fa ilure was examined at two different angles (26 and 0 degrees). Failure was measured in pounds with a force gauge over a 2000 pull cycle. The amount of force required to remove caps for two overdenture caps and a replaced cap for the metal keeper system was determined, Two depende nt variables were absolute force and relative force, Repeated measures analysis of variance (RMANOVA) was used to compare the between-subjec ts effects of cap and angle, and the within-subjects effect of pull, T he results indicated a significant difference between cap types (p < 0 .0001) with respect to the relative force required to remove the cap, There was no effect of angle, For absolute force, RMANOVA revealed a h ighly significant interaction between pull and cap (p < 0.0001), Thus, the way that force changed over pulls depended on which cap was used (no effect of angle). For relative force, RMANOVA revealed no interact ion between pull and cap, but there was a main effect of cap type (p < 0.0001) (no effect of angle), The nylon cap design required less forc e for removal but showed more consistency in the force required over t he course of the 2000 pulls when compared with the keeper with cap ins ert, The results obtained in this study were consistent with similar s tudies in literature.