Objective: to compare stresses induced from porcelain ,zirconia and acrylic teeth on implant retained mandibular over denture.
Material and methods: For group I Porcelain teeth were retained mechanicaly in the finished denture and a stone occlussal index was made. For group II; the finished complete dentures with porcelain teeth was scanned . An impression was made of the denture with porcelain teeth then poured. The teeth were reduced to simulate teeth preparation form for crowns , the prepared abutments were scanned.The computer program integrated the initial scan of fully contoured porcelain teeth onto the tooth preparation scan for milling of the fully anatomical zirconia restorations. The zirconia teeth were attached with tooth-colored acrylic resin to the denture base. For group III , the denture with porcelain was duplicated. Tooth colored acrylic resin was applied into the mold.
Universal testing machine was used to apply static load on the occlusal surface of the right first molar in vertical direction and microstrains were recorded .
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Results:
Two-way ANOVA test showed that the highest mean value was found in (Porcelain) while the least mean was found in (Acrylic). Post hock test showed significant difference between porcelain teeth group and other groups. It revealed statistically insignificant differences between zirconia and acrylic teeth .
Conclusions: zirconia teeth transmits less stresses than porcelain teeth and more stresses than acrylic teeth while porclain teeth transmits more stresses than both zirconia and acrylic teeth and finally the acrylic teeth showed the least amount of stressses