Abstract
Purpose: The purpose of this study was to pursue fabrication of dental casts that could create crown restorations with highly reproducible occlusal contacts.
Methods: Twenty adult dentulous subjects, each with individual normal occlusion, were selected. To fabricate the dental casts, we performed three types of conventional impression methods and one dual-arch method. A full-mouth impression of the bimaxillary dentition was taken using stock trays with an alginate impression material in a conventional impression method 1. The maxilla using a custom tray and silicone impression material, and the mandible using a stock tray with an alginate impression material in a conventional impression method 2. The third type of conventional impression method used contrary impression material and trays of a conventional impression method 2. Dental casts were produced with each method and mounted on articulators using the cast method. The dual-arch impression method was taken using a plastic tray and silicone impression material, and an occlusal relationship was reproduced on the articulator. Occlusal records of intraoral and dental casts were then prepared using an occlusal contact silicone checker, and add-pictures were extracted from these records. We then collated the classifications of Nakao occlusal facets sufficiently with the occlusal surface of the maxillary dentition model, the occlusal record, and the add-pictures, and the occlusal contact regions were identified. We counted the number of reproducible and nonreproducible regions from the comparison of occlusal contact regions of intraoral and dental casts. The obtained data were compared among each impression method with a repeated one-way ANOVA and a Tukey's test.
Results: It was shown that the dual-arch impression method had larger values than conventional impression methods did in the reproducible regions and smaller values in the nonreproducible regions.
Conclusions: We found that the dual-arch impression method was useful for the fabrication of dental casts with highly reproducible occlusal contacts.
