781 research outputs found

    Color-to-Grayscale Conversion Using a Smart Phone Camera for Value Comparison

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    A Method of Facilitating the Fabrication of Access Openings for Implant-Supported Complete Fixed Dental Prostheses

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    This report describes a method for fabricating access openings for implant-supported complete fixed dental prostheses (ICFP) by using a dental milling machine and silicone putty matrix. The method can help clinicians achieve the accurate and precise fabrication of access openings for ICFPs without excessive grinding

    Labial Reduction Guide for Laminate Veneer Preparation

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    This article describes a method of fabricating a labial reduction guide for laminate veneer preparations by using a digital tire tread depth gauge and orthodontic wire. The labial reduction guide can help clinicians to achieve accurate reduction of the labial surface. Minimally invasive porcelain laminate veneers have become a popular option in esthetic dentistry. Porcelain laminate veneers require only 25% to 50% of the amount of tooth reduction required for complete coverage restorations.Nevertheless, adequate labial reduction is important in creating optimal esthetics. However, excessive reduction can lead to compromised bond strength due to penetration of the enamel surface. Typically, the appropriate reduction is determined from a diagnostic waxing, and then a silicone index or thermoplastic matrix is made to guide preparation. Verifying the amount of reduction during tooth preparation from the guide can be problematic because the range of labial reduction for laminate veneers is small (0.3 to 0.9 mm). Freehand labial reduction can result in insufficient tooth removal.The purpose of this article was to describe the fabrication and use of a labial reduction guide (LRG) for laminate veneers

    Morphologic Custom Shade Guide Fabricated with Feldspathic Ceramic

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    Custom Total Occlusal Convergence Angle Sticker Fabrication

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    This article describes a method of fabricating a custom total occlusal convergence angle sticker with photo editing software and label stickers. The custom total occlusal convergence angle sticker can help clinicians achieve an accurate degree of taper during axial wall reduction of tooth preparation

    Customized Occlusal Reduction Guide Made from a Thermoplastic Sheet

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    Interproximal Distance Analysis of Stereolithographic Casts Made by CAD-CAM Technology: An in Vitro Study

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    Statement of problem The accuracy of interproximal distances of the definitive casts made by computer-aided design and computer-aided manufacturing (CAD-CAM) technology is not yet known. Purpose The purpose of this in vitro study was to compare the interproximal distances of stereolithographic casts made by CAD-CAM technology with those of stone casts made by the conventional method. Material and methods Dentoform teeth were prepared for a single ceramic crown on the maxillary left central incisor, a 3-unit fixed dental prosthesis (FDP) on the second premolar for a metal-ceramic crown, and a maxillary right first molar for a metal crown. Twenty digital intraoral impressions were made on the dentoform with an intraoral digital impression scanner. The digital impression files were used to fabricate 20 sets of stereolithographic casts, 10 definitive casts for the single ceramic crown, and 10 definitive casts for the FDP. Furthermore, 20 stone casts were made by the conventional method using polyvinyl siloxane impression material with a custom tray. Each definitive cast for stereolithographic cast and stone cast consisted of removable die-sectioned casts (DC) and nonsectioned solid casts (SC). Measurements of interproximal distance of each cast were made using CAD software to provide mean ±standard deviation (SD) values. Data were first analyzed by repeated measures analysis of variance (ANOVA), using different methods of cast fabrication (stone and stereolithography) as one within subject factor and different cast types (DC and SC) as another within subject factor. Post hoc analyses were performed to investigate the differences between stone and stereolithographic casts depending upon the results from the repeated measures ANOVA (α=.05). Results Analysis of interproximal distances showed the mean ±SD value of the single ceramic crown group was 31.2 ±24.5 μm for stone casts and 261.0 ±116.1 μm for stereolithographic casts, whereas the mean ±SD value for the FDP group was 46.0 ±35.0 μm for stone casts and 292.8 ±216.6 μm for stereolithographic casts. For both the single ceramic crown and the FDP groups, there were significant differences in interproximal distances between stereolithographic casts and stone casts (P\u3c.001). In addition, the comparisons of DC with SC of stone and stereolithographic casts for the single ceramic crown and FDP groups demonstrated there was statistically significant differences among interproximal distances between DC stereolithographic casts and SC stereolithographic casts only for the FDP group (P\u3c.001). Conclusions For both the single ceramic crown and the FDP groups, the stereolithographic cast group showed significantly larger interproximal distances than the stone cast group. In terms of the comparison between DC and SC, DC stereolithographic casts for the FDP group only showed significantly larger interproximal values than those of the SC stereolithographic casts for the FDP group

    Interproximal Distance Analysis of Stereolithographic Casts Made by CAD-CAM Technology: An in Vitro Study

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    Statement of problem The accuracy of interproximal distances of the definitive casts made by computer-aided design and computer-aided manufacturing (CAD-CAM) technology is not yet known. Purpose The purpose of this in vitro study was to compare the interproximal distances of stereolithographic casts made by CAD-CAM technology with those of stone casts made by the conventional method. Material and methods Dentoform teeth were prepared for a single ceramic crown on the maxillary left central incisor, a 3-unit fixed dental prosthesis (FDP) on the second premolar for a metal-ceramic crown, and a maxillary right first molar for a metal crown. Twenty digital intraoral impressions were made on the dentoform with an intraoral digital impression scanner. The digital impression files were used to fabricate 20 sets of stereolithographic casts, 10 definitive casts for the single ceramic crown, and 10 definitive casts for the FDP. Furthermore, 20 stone casts were made by the conventional method using polyvinyl siloxane impression material with a custom tray. Each definitive cast for stereolithographic cast and stone cast consisted of removable die-sectioned casts (DC) and nonsectioned solid casts (SC). Measurements of interproximal distance of each cast were made using CAD software to provide mean ±standard deviation (SD) values. Data were first analyzed by repeated measures analysis of variance (ANOVA), using different methods of cast fabrication (stone and stereolithography) as one within subject factor and different cast types (DC and SC) as another within subject factor. Post hoc analyses were performed to investigate the differences between stone and stereolithographic casts depending upon the results from the repeated measures ANOVA (α=.05). Results Analysis of interproximal distances showed the mean ±SD value of the single ceramic crown group was 31.2 ±24.5 μm for stone casts and 261.0 ±116.1 μm for stereolithographic casts, whereas the mean ±SD value for the FDP group was 46.0 ±35.0 μm for stone casts and 292.8 ±216.6 μm for stereolithographic casts. For both the single ceramic crown and the FDP groups, there were significant differences in interproximal distances between stereolithographic casts and stone casts (P\u3c.001). In addition, the comparisons of DC with SC of stone and stereolithographic casts for the single ceramic crown and FDP groups demonstrated there was statistically significant differences among interproximal distances between DC stereolithographic casts and SC stereolithographic casts only for the FDP group (P\u3c.001). Conclusions For both the single ceramic crown and the FDP groups, the stereolithographic cast group showed significantly larger interproximal distances than the stone cast group. In terms of the comparison between DC and SC, DC stereolithographic casts for the FDP group only showed significantly larger interproximal values than those of the SC stereolithographic casts for the FDP group

    Comparison of Accuracy and Reproducibility of Casts Made by Digital and Conventional Methods

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    Statement of problem Little peer-reviewed information is available regarding the accuracy and reproducibility of digitally fabricated casts compared to conventional nondigital methods. Purpose The purpose of this in vitro study was to compare the accuracy and reproducibility of a digital impression and cast fabrication with a conventional impression and cast fabrication. Material and methods Conventional impressions were made via a 1-step single viscosity technique with vinyl siloxanether material of a typodont master model, and conventional casts were cast from dental stone. Digital impressions were obtained with a digital scanner, and digital stereolithographic models were printed. The typodont and fabricated casts were digitized with a structured light scanner and saved in surface tessellation language (STL) format. All STL records were superimposed via a best-fit method. The digital impression and cast fabrication method was compared with the conventional impression and cast fabrication method for discrepancy, accuracy, and reproducibility. The Levene test was used to determine equality of variances, and a 1-way ANOVA was conducted to assess the overall statistical significance of differences among the groups (n=5, α=.05). Results No significant statistical difference was found between the digital cast and conventional casts in the internal area or finish line area (P\u3e.05). In addition, there was no statistically significant difference between these 2 techniques for a fixed dental prosthesis or single crown (P\u3e.05). However, statistically significant differences were observed for overall areas of the casts in terms of accuracy (PP Conclusions No statistically significant difference was found between the digital cast and conventional cast groups in the internal and finish line areas. However, in terms of the reproducibility and accuracy of the entire cast area, the conventional cast was significantly better than the digital cast
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