Marginal and Internal Crown Fit Evaluation of CAD/CAM versus Press-Laboratory All-Ceramic Crown Mohammed M. Beyari. Clinical Medicine and Diagnostics 2014, 4(1A): 21-26 Presented by Sucheta.P

Marginal and internal adaptation of ceramic crown restorations fabricated with CAD/CAM technology and the heat-press technique. Hisham A. Mously, Matthew Finkelman, Roya Zandparsa and Hiroshi Hirayama. J Prosthet Dent 2014;112:249-256 Evaluation of marginal and internal fit of ceramic and metallic crown copings using x-ray microtomography (micro-CT) technology. Manuel Antonio Pimenta, Luis Carlos Frasca, Ricardo Lopes and Elken Rivaldo. J Proshtet Dent 2015.

Comparison the Marginal and Internal Fit of Metal Copings Cast from Wax Patterns Fabricated by CAD/CAM and Conventional Wax up Techniques. Vojdani M, Torabi K, Farjood E, Khaledi AAR. J Dent Shiraz Univ Med Sci, Sept. 2013; 14(3): 118-129

INTRODUCTION Aim of the study

METHODS AND MATERIALS Preparation of the Master Model Duplicated as a replicated model made of type V dental stone (Die-KeenTM Green, Heraeus Kulzer). 45 individual impressions were taken with two- step impression techniques.

2. Fabrication of All-ceramic Crown a) CAD/CAM System Scanned with E4D handheld digital laser scanner The completed crown design data was transmitted wirelessly to the E4D milling unit which was loaded with IPSe.max® CAD LT A1/C14 all-ceramic block (Ivoclar Vivadent). b) Conventional Dental Laboratory System A total of thirty impressions were taken on the posterior left region area utilizing double arch impression techniques and a triple-bite tray The impressions were sent to two dental laboratories to fabricate the monolithic press ceramic crowns.

3. Crown Cementation and Analysis Ivoclar IPS e.max Press LT ingots (Low Translucency) were utilized and natural glaze was used with no additional staining or layering procedures. 3. Crown Cementation and Analysis The crowns were cemented using Multilink®Automix (Ivoclar Vivadent) under constant pressure of 100N. All samples were then stored in distilled water for 24 hours at 37⁰C. For sectioning, samples were embedded in clear acrylic resin and sectioned buccolingually in a consistent plane using the root indentations as guidance.

5. Statiscal methods - Mann-Whitney U tests Sections were measured under digital stereo microscope with 0.8X objective (Olympus SZX16) using OmniMet software on three different points per buccal and lingual side of section: marginal-edge, mid-axial wall, and cusp- tip. One measurement was made on the occlusal table. 4. Measurement landmark 5. Statiscal methods - Mann-Whitney U tests

RESULTS

CONCLUSION All-ceramic crowns produced using the E4D chair side CAD/CAM system had in vitro marginal fits that were not significantly different than marginal fits of all-ceramic crowns produced by two independent dental laboratories.

Marginal and internal adaptation of ceramic crown restorations fabricated with CAD/CAM technology and the heat-press technique. Hisham A. Mously, Matthew Finkelman, Roya Zandparsa and Hiroshi Hirayama. J Prosthet Dent 2014;112:249-256

MATERIALS AND METHODS A complete coverage preparation on the mandibular right first molar was made for a typodont model. 40 acrylic resin master dies were fabricated by duplicating the prepared tooth with an In-lab CAD/CAM system (Tizian Cut 5; Schütz Dental Gmb). The master dies were divided into 4 groups (10 dies per group). Each master die was assigned to each of these 4 groups.

Spacer settings for lithium disilicate complete coverage restorations To fabricate the restorations, in the CAD/CAM-30 group, the internal and marginal gaps were set at 30 mm with a 1-mm marginal ramp; in the CAD/ CAM-60 group, the internal and marginal gaps were set at 60 mm with a 1-mm marginal ramp; in the CAD/ CAM-100 group, the internal and marginal gaps were set at 100 mm with a 1-mm marginal ramp. Milling process and crystallization Two layers of die spacer (Euro Quick Set; Kerr Dental Laboratory Products) were applied to the stone dies. The layers were applied uniformly with a brush, starting 1 mm short of the finish lines of the preparations.

Micro-XCT scan image (horizontal cut): 10 vertical cuts obtained with 50 slices between buccolingual cuts and 25 slices between mesiodistal cuts. Micro-XCT scan image : measurement of marginal gap (for overextended crown, perpendicular distance between internal surface of crown and master die margin was measured and absolute marginal discrepancy (distance between crown and master die margins).

Micro-XCT scan image (vertical cut): Measurement of axial gap and occlusal gap (measured distances were perpendicular to ceramic crown and master die internal surfaces at selected points).

RESULTS

CONCLUSIONS 1. Different fabrication techniques affected the marginal and internal adaptation of ceramic crown restorations. 2. The spacer thickness setting is an important factor that should be considered before fabricating ceramic CAD/CAM restorations. 3. The heatpress group yielded the best results with respect to marginal and internal crown adaptation. 4. Among the CAD/ CAM groups, the CAD/CAM-30 group yielded the lowest AG values, whereas the CAD/CAM-30 and CAD/CAM-60 groups yielded the lowest OG values. 5. When considering the results of the marginal and internal adaptation of all the CAD/CAM crowns, the 30- or the 60-mm spacer settings were recommended for the E4D CAD/CAM system.

Evaluation of marginal and internal fit of ceramic and metallic crown copings using x-ray microtomography (micro-CT) technology. Manuel Antonio Pimenta, Luis Carlos Frasca, Ricardo Lopes and Elken Rivaldo. J Proshtet Dent 2015.

MATERIALS AND METHOD Materials used were zirconia (ZirkonZahn system, group Y-TZP), lithium disilicate (IPS e.max Press system, group LSZ), and nickel-chromium alloy (lost-wax casting, group NiCr). Five specimens of each material were seated on standard dies. An x-ray microtomography (micro-CT) device was used to obtain volumetric reconstructions of each specimen. Points for fit measurement were located in Adobe Photoshop, and measurements were obtained in the CTAn SkyScan software environment.

Marginal fit was measured at 4 points and internal fit at 9 points in each coping. Mean measurements from the 3 groups were compared by analysis of variance (ANOVA) at the 5% significance level, and between-group differences were assessed with the Tukey range test.

RESULTS

CONCLUSION Cast metal alloy exhibited the best marginal fit and lithium disilicate exhibited the best overall internal fit. The overall assessment of the results showed that, despite significant differences in fit, all tested materials were within clinically acceptable range.

Comparison the Marginal and Internal Fit of Metal Copings Cast from Wax Patterns Fabricated by CAD/CAM and Conventional Wax up Techniques. Vojdani M, Torabi K, Farjood E, Khaledi AAR. J Dent Shiraz Univ Med Sci, Sept. 2013; 14(3): 118-129

Twenty-four standardized brass dies were prepared and randomly divided into 2 groups according to the wax-patterns fabrication method (CAD/CAM technique and conventional method) (n=12). All the wax-patterns were fabricated in a standard fashion by means of contour, thickness and internal relief (M1- M12: representative of CAD/CAM group, C1-C12: representative of conventional group).

CAD/CAM milling machine (Cori TEC 340i; imes-icore GmbH, Eiterfeld, Germany) was used to fabricate the CAD/CAM group wax-patterns. The copings cast from 24 wax-patterns were cemented to the corresponding dies.

For all the coping-die assemblies cross-sectional technique was used to evaluate the marginal and internal fit at 15 points. The Student’s t- test was used for statistical analysis (α=0.05).

RESULTS

CONCLUSIONS 1. The conventional method of wax-patterns fabrication resulted in better marginal and internal fit of final copings than CAD/CAM milled wax-patterns at all measured area. 2. The marginal and internal fit of copings cast from CAD/CAM milled wax-patterns were clinically unacceptable. 3. Although CAD/CAM technology has already changed dentistry, it needs some improvement in scanning procedure, data processing, manufacturing techniques and material processing to be a competitive alternative for conventional method of fabrications.

CONCLUSION

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