Faculty Bibliography

BACKGROUND/PURPOSE/UNASSIGNED:Digital impressions using intraoral scanners have recently gained popularity. The aim of the present study was to evaluate the fit of full-arch screw-retained cobalt-chromium frameworks fabricated via two different digital impression methods. MATERIALS AND METHODS/UNASSIGNED:An edentulous resin master model with four dental implants was fabricated. Forty cobalt-chromium superstructures were fabricated and evaluated according to four groups. In Group 1, the superstructures were evaluated using an intraoral scanner to generate digital impressions. Group 2 relied on the help of an auxiliary geometric appliance in generation of digital impressions via intraoral scanner. The traditional method of splinted open-tray conventional impressions was designated for Group 3. Finally, the control group (Group 4) relied on scanning of the master model directly with a laboratory scanner. Vertical marginal discrepancy was evaluated, and data obtained were statistically analyzed. RESULTS/UNASSIGNED: > 0.05). CONCLUSION/UNASSIGNED:It has been suggested that the use of auxiliary geometric appliances yields increased scanning accuracy. Frameworks fabricated using the traditional splinted open-tray technique were more reliable compared to those frameworks from digital impressions.

PURPOSE/UNASSIGNED:A range of materials for single-tooth computer-aided design and computer-aided manufacturing (CAD-CAM) restorations have been introduced that may affect CAM accuracy. This study aimed to review articles evaluating marginal and internal fit of lithium disilicate (LD) and zirconia (Z) crowns fabricated by CAD-CAM systems using intraoral optical scanners (IOS). MATERIALS AND METHODS/UNASSIGNED:Under the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA), a systematic review was performed along with an electronic article search in the Medline/Pubmed database. The articles were limited to those in the English language that were published within the past ten years. RESULTS/UNASSIGNED:The initial search resulted in 50 articles and of those, a total of 18 articles were selected for full-text review following abstract evaluation. Eight articles that did not meet the inclusion criteria were excluded and the remaining ten articles, which provided internal and marginal gap values, were used in this review. For LD crowns, marginal gap values ranged between 45µm and 190.2µm. For Z crowns, the values varied between 39µm and 126.4µm. For LD crowns, the internal gap values were between 57.8µm and 475.4µm, and for Z crowns, the values were between 79µm and 205.8µm. CONCLUSION/UNASSIGNED:The outcome of this review suggests that clinically acceptable marginal and internal fit can be attained with LD and Z all-ceramic CAD-CAM crowns using digital impressions. Additionally, it has been found that LD and Z ceramics provide similar marginal gap values, but LD material provides better internal fit than Z.

This report presents a clinical case that follows a comprehensive digital workflow to increase occlusal vertical dimension of a patient presenting with occlusal wear. A 56-year-old patient with aesthetic and functional problems presented to the authors' clinic. An intraoral scanner was used to obtain digital models of the patient's existing maxillary and mandibular arches. Advanced sculpting software and digital tooth libraries were used to design the patient's ideal smile. A three-dimensional (3D) printer was used to fabricate temporary restorations and resin casts. Full-mouth restoration was successfully completed with zirconia crowns using an advanced digital workflow.

Background/purpose: The ability to save a digital copy of a fabricated denture is poignant for large dental institutions. The purpose of this study was to evaluate the trueness and precision of an intraoral scanner (IOS) in its ability to digitally duplicate a complete denture (CD) and evaluate the possible effects of file resolution reduction on different exported media types. Materials and methods: A desktop scanner was used to scan a complete mandibular denture and utilized as the control file. An IOS was used to scan the same denture and exported into both standard triangular language (STL) and polygon (PLY) file types and stored for additional analysis. The different file types at original resolution were compared to the desktop scan (DS100) to evaluate the accuracy of the IOS. Then the STL (Groups S100, S75, S50, S25) and PLY (Groups P100, P75, P50, P25) files were reduced in their resolutions to evaluate any statistical discrepancies in the volumetric analysis of the scan using the Hausdorff distance (HD) and dice similarity coefficient (DSC). Results: When compared to the desktop scan (14888.40 mm³), the measured volume of the exported STL (Group S100: 15236.45 ± 114.67 mm³) and PLY (Group P100: 15231.71 ± 97.12 mm³) files from the IOS produced a similarity of 98.34% and 98.39% respectively. The similarity of the IOS files at different resolutions ranged from 99.99% to 99.96%. Conclusion: We conclude that the IOS used in this study demonstrates very high trueness and precision when digitally duplicating complete dentures.

BACKGROUND/PURPOSE/UNASSIGNED:Zirconia has recently become a popular material for fixed restorations. The purpose of this study was to use a digital workflow to fabricate monolithic zirconia fixed dental prostheses (FDPs) and assess the connection between variable connector sizes compared to their clinical performance. MATERIALS AND METHODS/UNASSIGNED:for the 4-unit restorations (pontic to pontic). Biological an technical outcomes of the FDPs were performed at 1 week, 6 months and then annually for 6 consecutive years. RESULTS/UNASSIGNED:in the two broken 4-unit FDPs. CONCLUSION/UNASSIGNED:The results of this study suggest that the use of digital scanning and milling to fabricate monolithic zirconia FDPs of posterior regions may be an acceptable alternative restorative approach to traditional metal-ceramic restorations.

PURPOSE/UNASSIGNED:The purpose of this systematic review was to compare the clinical performance of lithium disilicate (LDS) and zirconia (Z) single crowns manufactured by computer-aided design/computer-aided manufacturing (CAD/CAM) systems using intraoral optical scanners (IOS). MATERIALS AND METHODS/UNASSIGNED:An electronic search for articles published between January 2012 and January 2022 in the English language was performed with the Medline/Pubmed database under the guidelines of Preferred Reporting Items for Systemic Reviews and Meta-analysis (PRISMA). The specific search terms used were "zirconia", "lithium disilicate", "CAD/CAM", "intraoral optical scanner", and "survival". RESULTS/UNASSIGNED:The initial electronic search resulted in 278 articles. Most of the resulting articles were excluded, six clinical studies addressing the clinical outcomes of Z and LDS crowns fitted the inclusion criteria and were selected for review. Of these six studies, three were randomised controlled trials, two were retrospective studies, and one was a prospective study. To quantify the clinical performance of the crowns several parameters were recorded, including fractures, endodontic complications, periodontal complications, technical complications, aesthetic complications, and biological complications. It was noted that the most common technical complication of Z and LDS crowns was chipping at a rate of 1.4% and 5% respectively. Regarding Z crowns, aesthetic concerns were the most frequently observed complication. CONCLUSION/UNASSIGNED:The outcomes of this systematic review indicate that Z and LDS crowns display a similar incidence of periodontal and endodontic complications when compared to metal-ceramic crowns, suggesting that these all-ceramic materials are viable alternatives. The incidence of chipping was higher in LDS crowns compared to other materials, while Z crowns were inferior in terms of aesthetics.