The influence of edentulous area’s distribution on the marginal and internal fit of CADCAM multi-unit zirconia framework

Abstract

Dimensional discrepancies of a long-span zirconia framework may result from unfavorable sintering shrinkage or different edentulous conditions The purpose of this study was to evaluate the marginal and internal fit of five-unit zirconia frameworks with various distributions of pontics after sintering process Three experimental groups with different edentulous conditions were designed as follows: Group A- missing maxillary lateral incisor and canine; Group B- missing maxillary lateral incisor and first premolar; and Group C- missing maxillary canine and first premolar was fabricated After sintering the specimens were examined using Computer-aided replica technique to evaluate their marginal and internal discrepancies Five critical regions were measured including mesial marginal gap (MMG) mesial axial wall (MAW) occlusal surface (OS) distal axial wall (DAW) and distal marginal gap (DMG) The data of the measurements were statistically analyzed with 1-way ANOVA (?= 05) The results showed that the largest discrepancies in all groups appeared at the occlusal surface In the comparison of the discrepancies in the terminal abutments between the experimental groups statistical differences were found in MAW OS DAW (ρ< 05) In the comparison of the discrepancies in the non-terminal abutments statistical differences were found in MMG MAW OS (ρ< 05) Due to the unfavorable sintering shrinkage of zirconia the largest deformation of the zirconia framework appeared at the occlusal surface The pontics’ distribution can cause the dimensional discrepancies after sintering process

Date of Award	2020
Original language	English
Supervisor	Yung-Chung Chen (Supervisor)