THE SHEAR-STRENGTH OF POLYMETHYL METHACRYLATE BONDED TO TITANIUM PARTIAL DENTURE FRAMEWORK MATERIAL

Premachined titanium frameworks are used in implant-supported fixed co mplete-arch prostheses. Traditionally, retentive mechanisms are incorp orated in the wax patterns to provide retention between polymethyl met hacrylate and the cast framework. Nontraditional forms of retention ar e needed with machined frameworks. This study determined whether three different surface characteristics of titanium improve the bond shear strength of polymethyl methacrylate, Thirty rod shaped specimens of ti tanium were divided into three equal groups: group 1 received no pretr eatment; group 2 was pretreated with 110 mum alumina air abrasive; and group 3 was pretreated with 110 mum alumina air abrasive plus silane (clear). Denture resin was processed around each specimen. A Shell-Nie lsen shear test was then performed at a crosshead speed of 0.5 mm/minu te to determine the bond shear strength in kilograms per square centim eter. The bond shear strength of group 3 was 63% greater than group 1 (significant, p < 0.01; ANOVA-Scheffe interval 63 kg/cm2). The results of this study indicated that surface pretreatment of titanium with 11 0 mum alumina air abrasive plus silane coating significantly enhances the bond shear strength of polymethyl methacrylate.