“Effect of Internal Friction and Cement Space on Cervical Seating and Internal Fit of Vertical and Horizontal Preparations of All Ceramic Crowns” (An In vitro Study)

Abstract

The current study evaluated the effect of preparation designs and different cement spaces application on internal fit and cervical seating of multilayered super translucent zirconia crowns. Two typodont teeth (mandibular second molar) were prepared to receive full coverage restorations using two margin designs: Horizontal (chamfer) and vertical (feather edge) preparations, the two prepared typodont teeth were duplicated to produce two epoxy resin master dies then the two master dies were duplicated 20 times for each master die to form Forty resin epoxy dies divided into two groups according to preparation designs (n=20): • Group H: Teeth prepared with horizontal finish line (chamfer finish line). • Group V: Teeth prepared with vertical finish line (feather edge). Each group will be subdivided into two subgroups according to cement space approach (n=10): • Subgroup (A): 80 micron cement space applied to all die surfaces except the cervical third minimal cement space 50 microns (Approach A). • Subgroup (B): 80 micron cement space applied to all die surfaces except the occlusal third minimal cement space 50 microns (Approach B). Each sample was vertically sectioned bucco-lingually around cemented crowns. Sectioning was specified at a line drawn between the mesial and distal cusps across the buccal and lingual grooves.