Evaluation of fit of zirconia posterior bridge structures constructed with different scanning methods and preparation angles

Abstract

This study evaluated the influence of scanning method, abutment position, and preparation angle on the vertical seal of three-unit posterior zirconia structures. Sixty differently angled metallic models were machined to receive 30 bridge frameworks. For each preparation type, half of the structures were waxed-up and digitized, whereas the other half were computer-designed after the abutments were scanned. Once milled, the samples were cemented in standard fashion. Misfit was assessed by scanning electron microscopy. Three-way analysis of variance showed significant differences. Computer-designed structures achieved the highest accuracy (P< 0.0001). No significant differences were recorded concerning the abutment position and convergence angle. All discrepancy values were within the clinically acceptable range.

A systematic review of CAD/CAM fit restoration evaluations

“…Regarding the bridge framework , the absolute marginal gap is from 9 ± 5 26 μm to 206·3 ± 56·3 μm . Next, the vertical marginal fit is from 9 ± 10 μm to 197·3 ± 57 μm and the horizontal marginal gap is from 49·4 μm to 85·8 ± 27·1 μm .…”

“…This replica is sectioned and evaluated under light or electronic microscopy . Measurement of the tooth–prosthetic interface after cementing or bonding dental prostheses. The spacer is evaluated with light or electronic microscopy after sectioning .…”

Vertical discrepancy and microleakage of laser-sintered and vacuum-cast implant-supported structures luted with different cement types

“…31 The significance level was set at a = 0.05 for all statistical tests. [29][30][31] All data analyses were made with SPSS/PC+ v.17.0 (SPSS Inc., Chicago, IL, USA) statistical software.…”

“…Since no interaction that involved the framework alloy and fabrication technique or the cement type resulted in a significant intra-group difference between the paired abutments, a three-way ANOVA was run by using the bridge retainer as an additional independent variable. 29 Multiple post hoc comparisons between pairs of means were performed using the Student-Newman-Keuls (SNK) multiple range test. 30 Kruskal-Wallis and Dunn's tests were used to identify statistically significant differences in marginal microleakage scores.…”

Micro-CT analysis of in-office computer-aided designed/computer-aided manufactured dental restorations

“…In addition, it also has the advantage of being a non-destructive method. It provides faithful three-dimensional reconstructions and allows an analysis by slices and sections every 8 micron in any plan you want in order to not overlap, differently to other techniques such as scanning electron microscopy (Reich et al 2008;Oyague et al 2010). In this way, measurements can occur in different sections and distances along the marginal zone.…”