[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to investigate the fit of acrylic maxillary denture bases processed by the methods of microwave, quick-wet-heat, slow-wet-heat, and self curing. Forty stone-casts were obtained using a mould of an undercut-free acrylic resin master cast of an edentulous maxilla. Standard acrylic replicas patterns sealed on casts and randomized to four groups (10 in each) were used to make denture bases using different processing methods for each of the four groups. The resultant discrepancy of fit between the denture base and the casts were measured using a silicone wafer. Varying fit discrepancies both within and between denture base groups was observed. The proportional fit-loss in the palatal region was significantly greater than the sulcular areas for all materials tested (p < 0.05). The fit-loss observed was greater in microwave-cured bases than for other materials examined. Careful selection of appropriate denture base materials and processing technique is important when providing complete dentures for edentulous patients.
The European journal of prosthodontics and restorative dentistry 09/2010; 18(3):132-8.
[Show abstract][Hide abstract] ABSTRACT: Physical retention of a denture depends on adhesion of a salivary film to its fitting surface and supporting tissues. Adhesion is influenced by many factors.
This study examined the effect of the texture of the fitting surface on denture retention.
According to the method developed, mucosal-supported palatal bases were made for 10 dentate subjects who had no obvious oral disease, history of allergy to dental materials, or palatal mucosal undercuts. A specially designed strain gauge force transducer and a pen-chart recorder were used to record forces that were needed to dislodge the bases from the palate. Forces were recorded 30 times (10/day) for each subject. Similar forces were recorded after the fitting surface of each base was uniformly air-particle abraded under 4 kg/cm2 of pressure for 1 minute with 50-microm grit alumina dust. Data were analyzed with a 2-sample Student t test and a paired t test.
Substantial variations for all measurements were observed both between and within subjects. Notwithstanding, these variations, the mean retention of the bases significantly (P <.05) increased by more than 2-fold when the fitting surface was air-particle abraded. These force values were similar to those recorded previously for well-fitting mucosal-supported palatal bases in a separate group of dentate subjects.
While reinforcing the importance of good adaptation of the denture to the tissues, these findings also suggest that an additional improvement in denture retention can be accomplished after the fitting surface is air-particle abraded.