THE EFFECT OF STORAGE TIME OF REMOVABLE PARTIAL DENTURE WAX PATTERN ON THE ACCURACY OF FIT OF THE CAST FRAMEWORK

Statement of problem. Situations may arise in dental laboratories that could result in a time lapse between preparing the wax pattern of the removable partial denture framework and its casting into the cobalt-c hromium alloy. Purpose. This study investigated the effect of storage time of the wax pattern before casting and the influence of the palata l major connector design on the accuracy of its fit on the master cast s. Material and methods. Forty-two frameworks were prepared with two d esigns of major connectors,; which were divided into three subgroups a ccording to the storage time of the wax patterns: 24 hours, 1 week, an d 1 month. Discrepancies in the fit of the connectors to their respect ive casts were measured at specific locations for both connector desig ns. Results. In both framework design groups, there was a significant deterioration in fit (p < 0.0005) of the major connectors with the inc rease in storage time of their wax patterns on their respective refrac tory casts. Gap discrepancies were more pronounced towards the center of the palate. Conclusions. The greatest discrepancies appeared at the middle sections of the connectors more than at the lateral sections ( p < 0.0005). Furthermore, frameworks with modified palatal plate major connectors exhibited greater inaccuracies in their fit than those wit h the anterior posterior palatal strap design, as evidenced by the inc rease in mean gap discrepancies under the palatal plate design (p < 0. 0005).