Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Prosthodontic

Aim: In vitro study was carried-out to compare the dimensional stability for two types of acrylic resin and flexible resin during and after maxillary complete denture processing. Materials and methods: A standard complete denture was constructed and duplication for sixteen dentures was done using duplicating silicone mold then the dentures were divided into two groups (n=8): Group A: valplast flexible dentures processed by injection molded technique; Group B: vertex rapid (fast) heat curing acrylic resin dentures processed in boiling water for 20 min. Metallic reference pins were placed in the central fossae of the first premolars, and second molars, and immediately below the neck of these teeth in buccal flange. Width, length and cross arch measurements were measured before and after the complete dentures processing using a digital caliper with manufacturing accuracy of up to 0.01 mm; Image analysis method and Full-Field 3D Comparisons of Obtained Dentures. Gap between the stone casts and dentures were measured using the same methods, all collected data were tabulated and subjected to analytical tests used for all parameters (one-way analysis of variance ANOVA and Bonferroni t-test for pairwise comparison) to assess significant changes within each group over time and (independent t-test) to compare the two groups. Cluster Analysis was used to measure the proximity of the obtained casts{u2019} measurement to that of the control group. Results: The results show that there was statistically significant difference between the two types of dentures{u2019} materials and when compared with the standard conventional denture; group B was much closer to it than that of the Group A. There was statistically insignificant difference between the measurements made by computerized and manual methods It was concluded that the dimensional accuracy of vertex rapid (fast) heat curing acrylic resin dentures is better than that of valpast flexible injection molded dentures

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