Posterior peripheral seal distortion related to height of the maxillary ridge.

A statistically significant positive relationship exists between ridge height of a cast and dimensional changes in the posterior peripheral seal region of its denture base. This dimensional change might be clinically insignificant, but it should not be ignored. The relationship between distortion of the denture base and composition of the denture teeth is not significant. The relationship of distortion of the denture base at the region of the posterior peripheral seal and variables of ridge height and tooth composition were studied. A positive relationship exists between ridge height and distortion, but no significant relationship was found between dimensional change and the use of porcelain or acrylic resin teeth. Using computer analysis, an equation, table, and curve were derived for values of expected dimensional change in the posterior peripheral seal region related to various ridge heights.