Influence of the Fast-processing Technique on the Number of the Occlusal Contacts and Occlusal Vertical Dimension of Complete Dentures

Abstract

Aim: Occlusal errors during acryl processing affect the retention and stability of complete dentures. The aim of the present study was to assess the influence of a short curing technique on the number of occlusal contacts and the occlusal vertical dimension (OVD) of complete dentures. Materials and methods:Complete dentures were prepared. The number of occlusal contacts was recorded in centric relation (CR) using 60 µ articulation paper. The OVD was recorded with the waxed trial denture in place. Dentures were then invested and processed with compression molding and short cure water bath technique. The number of occlusal contacts was recorded again. The amount of pin opening was measured for all of the complete dentures on the articulator. Data were analyzed with paired t-test to determine the alterations. Results:The mean number of occlusal contacts before and after processing was 10.9 ± 2.4 and 6.3 ± 3.1 respectively (4.7 ± 1.9 decrease; p < 0.001). A 2 mm mean increase in OVD was observed in 47.7% of the dentures with < 6 occlusal contact changes and 88.9% of the dentures with ≥ 6 occlusal contact changes (p < 0.003). A significant change in the number of occlusal contacts was associated with an OVD increased up to two times. Conclusion:The short curing technique seems to be related to the decreased occlusal contacts and increased OVD. Clinical significances:More time is needed to adjust the occlusal errors of this method, because it has a negative effect on the morphologic pattern of artificial teeth of complete dentures and thus should be used carefully.

Linear Dimensional Change in Acrylic Denture Teeth Positions Factored by Different Processing Techniques and Occlusal Forms: An In Vitro Study

“…They also proposed that teeth in the mold are carried to a different position due to the reconstitution of the gypsum on heating, cooling and compression. Additionally, the short curing technique has shown an increase in the vertical dimension and a lower number of occlusal contacts [37]. However, in the present study, utmost precaution was taken to maintain the same amount of acrylic used for each denture, standardized pressure during flask closure and a long curing cycle to reduce the effect of these factors on the movement of teeth.…”

Attempts to Minimizing Incisal Pin Opening During Processing of Complete Dentures

“…Decreased number of the occlusal contacts and the increased VDO may be related to compression during molding, to the heating intensity and duration, or may be related to the non-uniform thickness in the flanges, 30 since the inherent characteristics of heat curing acrylic resin produce internal stresses that are released during the deflasking stage, which result in dimensional changes and denture base distortion. 18 It is thought that minimizing the IPO was due to the release of the strain through the free ends of the sprues where the packing pressure of the acrylic resin produce strain inside the denture base and the acrylic injected within the holes produced by the wax elimination of the sprues.…”