Salinas, Thomas J

Abstract Purpose This study evaluated and compared the marginal fit of CAD–CAM zirconia crown copings with and without a 3D‐printed control model. Materials and Methods This prospective in vitro trial involved 30 zirconia crown copings made from the same STL file. These were divided into two groups. Half of them had their own 3D‐printed control model made from the same STL file (With‐Printed‐Model group), whereas the other half lacked any control model (No‐Printed‐Model group). Both groups underwent manual adjustments in a systematic way. Their marginal gaps were evaluated using a digital optical microscope from eight zones: buccal, mesiobuccal, mesial, mesiopalatal, palatal, distopalatal, distal, and distobuccal. Results The mean values with standard deviations for the With‐Printed‐Model and No‐Printed‐Model groups were 15.18 ± 14.49 and 12.46 ± 14.09 µm, respectively. All crown copings from both groups were below 75 µm. Statistical analysis showed a significant difference between the two groups. Conclusion The No‐Printed‐Model group demonstrated superior marginal fit compared to the With‐Printed‐Model group. However, the largest marginal gaps from each group were still within the clinically acceptable range below 75 µm. Although the 3D‐printed control model did not improve marginal fit, its primary function is to effectively identify major manufacturing errors.

AbstractPurposeThe purpose of this Best Evidence Consensus Statement was to search the literature to determine if there is a relationship between patient specific factors and occlusal force.Materials and MethodsA literature review was conducted in the following databases: Evidence‐Based Medicine Reviews (EBMR), Cochrane Database of Systematic Reviews, Embase, and Ovid MEDLINE(R) and Epub Ahead of Print. Articles on patient factors and occlusal force were compiled by using a combination of the key words: “bite force,” “occlusal force,” “partial and complete edentulism,” “bruxism,” and “orthognathic class.” Inclusion criteria included meta‐analyses, systematic reviews, randomized controlled trials, case series, and journal articles. Exclusion criteria were case reports, studies in children, animals, and bench studies.ResultsOf the 1502 articles that met the initial search criteria, 97 related to patient‐specific factors affecting occlusal forces. These articles were evaluated, rated, and organized into appropriate categories addressing questions of foci.ConclusionsThe range of occlusal force is highly variable among subjects correlated to patient specific factors such as age, gender, partial and complete edentulism, the presence of a maxillofacial defect, location of edentulous area, orthognathic profile, and magnitude of occlusal vertical dimension. Tooth replacement therapies targeted at increasing occlusal contact seem to have a positive effect on increasing occlusal force. Bruxism does not necessarily demonstrate higher occlusal powering but may have greater tooth contact time. Occlusal force is not clearly affected by the type of dental restoration or restorative material used. The clinical significance of the changes in occlusal forces is yet to be determined.