A comparison of palatal adaptation in acrylic resin denture bases using conventional and anchored polymerization techniques

Purpose: The study investigated the effects of palatal depth and a resin anchoring system on the adaptation of denture base resin to the master cast after compression molding and heat polymerization. Materials and Methods: Forty-eight virtually identical polymethyl methacrylate dentures were fabricated on master casts with either a deep or shallow palatal vault. One half of the master casts of each palate type were altered by the addition of anchoring holes along the posterior land area, as well as perpendicularly in the midsaggital area. Anchoring holes were made with a #8 round bur to a depth of 5 mm. Twenty-four hours after polymerization, the bases on their casts were sectioned at the posterior border and evaluated for degree of adaptation using a traveling microscope. Maladaptation at the interface of the denture base and master cast was measured at predetermined mediolateral locations. A split-plot analysis of variance (α = 0.05) was performed followed by a post-hoc Dunn Multiple Comparison Test. Results: In general, depth of the palatal vault did not significantly influence denture palatal discrepancy (p = .0780), but the use of the anchoring system significantly reduced mean gap distances (p = .000). At lateral and midpalate locations, gap distances between the denture bases and their casts were reduced from approximately 0.3 mm to approximately 0.1 mm when the anchoring system was used. Conclusions: Mean gap distances for steep palate dentures were significantly less than shallow palate dentures at vestibule and lateral palate locations, and anchoring holes placed in an edentulous master cast along the posterior land area and at the midline significantly improved the adaptation of denture bases. J Prosthodont 2001;10:204-211.