Marginal discrepancy dimensions of single unit metal crowns fabricated by using CAD-CAM–milled acrylate resin polymer blocks or a conventional waxing technique

Lalande, David; Hodd, Jeffrey A.; Brousseau, J. S.; Ramos, Van; Dunham, Daniel D.

doi:10.1016/j.prosdent.2017.07.019

Cited by 7 publications

(7 citation statements)

References 16 publications

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“…Insignificant difference in internal gap values between conventional wax (103.89 μm ±40.39) and CAD wax specimens (104.10 μm ±39.96) might be because inaccuracies were equally weighed in both groups. This was found to be in agreement with some studies (1,2,5) . The results of the study are in contradiction with Farjood et al, (3) where CAD wax experienced greater discrepancy probably due to use four axis milling machine.…”

Section: Discussionsupporting

confidence: 94%

“…A metal die was milled to resemble the dimensions of reduced mandibular first molar with rounded shoulder finish line (5) . Resin dies were used to simulate tooth structure as they have similar modulus of elasticity to that of dentin (12.9 GPa) (4) The conventional lost wax technique includes multiple manual steps resulting in greater chance for errors (2,18) .…”

Section: Discussionmentioning

confidence: 99%

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Comparison of the Internal fit of conventional casting versus CAD wax (In-vitro Study)

Mansour

2021

Egyptian Dental Journal

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Statement of Problem: The accuracy of internal fit for subtractive CAD-CAM systems used in the fabrication of metal coping is still unclear. Purpose: This in vitro study compared the internal fit of casting metal core using conventional wax versus CAD wax. Material and Methods: Twenty four resin specimen dies were randomly divided into two groups according to method of metal coping construction using conventional (C) or CAD (D) wax. The silicon replica technique evaluated the internal fit using stereomicroscope at ×24 magnification; the thickness of the silicon layer was measured at 20 reference points on each specimen. Parametric data of internal gap width was analyzed using one-way ANOVA. Results: Different techniques of wax construction showed insignificant difference in internal gap values between specimens made with conventional (C) (103.89±40.39) and CAD (D) waxing (104.10±39.96). However, there was a significant difference between internal gap values measured at different sites. Conclusions: Both construction techniques of casting were considered reliable in production within a clinically acceptable range regarding internal fit.

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Section: Discussionsupporting

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Comparison of the Internal fit of conventional casting versus CAD wax (In-vitro Study)

Mansour

2021

Egyptian Dental Journal

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“…This was found to be in accordance with some studies. 2 , 8 , 12 CAD wax quality depends on software quality, milling precision of the virtual restoration and scanner that might elevate die geometry by rounding edges during scanning. 12 Inaccuries related to conventional waxing up are related to operator skills and amount of die spacer placed.…”

Section: Discussionmentioning

confidence: 99%

“…A master metal die was milled (with dimensions of 5.5 mm in height, 9.5 mm cervical diameter, 8 mm occlusal diameter, 1.2 rounded shoulder finish line with an axial taper of 7° and two planes were made occlusally) to resemble preparation of mandibular first molar for construction of full coverage ceramometallic restoration. 12 , 13 Metal die was duplicated to 24 resin dies (Kemapoxy resin, CMB, Egypt) using polyvinylsiloxane duplication material (Ecosil, Dentarum, Germany) 14 and randomly divided into two equal groups according to method of metal coping construction using conventional (C) or CAD (D) wax. 15 – 17 According to previous studies 15 , 16 12 specimens were calculated in each group representing an 80% power.…”

Section: Methodsmentioning

confidence: 99%

Assessment of internal fit and micro leakage of conventionally fabricated ceramometallic restoration versus CAD wax and press veneering (in-vitro study)

et al. 2021

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Statement of problem Accuracy of internal fit and microleakage for CAD-CAM systems used in metal coping fabrication and veneered with layering or pressing porcelain in ceramometallic restoration is unclear. Material and methods A master metal die was milled to resemble the right mandibular first molar preparation for coverage with ceramometallic restoration. Master die was duplicated to twenty-four resin specimen dies.They were divided into two groups according to metal coping construction technique using either conventional (C) or CAD (D) wax. Each group was subdivided into two subgroups (n = 6) according to the technique of porcelain veneering (layered or pressed) to fabricate ceramometallic restorations, where subgroup (CL, DL) were conventionally layered by porcelain and (CP, DP) were press veneered. A standardized thickness of metal and porcelain was performed in all specimens as per manufacturer’s instructions for techniques ceramometallic restoration construction. Evaluation of internal fit was done with silicone replica technique using stereomicroscope at ×24 magnification where the thickness of silicon layer was measured at 20 reference points on each specimen. Then specimens were subjected to thermocycling. Sectioned specimens were assessed for microleakage using a stereomicroscope at ×12 magnification along die-cement interface with a five scale score. Results Mean internal gap values of veneering showed a statistically nonsignificant difference between specimens made with layering(L) and pressing(P). Different techniques of wax construction showed a non-significant difference in internal gap values between specimens made with conventional(C) and CAD(D) waxing. However, a significant difference was found in the internal gap at different sites. The highest internal gap was found at the occlusal surface, while the lowest gap was found at the finish line. The highest mean microleakage score was found with CAD wax and press veneering, while the lowest mean microleakage score was found with conventional wax and press veneering. Conclusion Both construction techniques of ceramometallic restoration were considered reliable in restoration production within a clinically acceptable range regarding internal fit and microleakage. There is a strong positive correlation between internal fit and microleakage of ceramometallic restoration constructed.

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“…22 Recent studies have reported contradictory results for the marginal discrepancy of restorations made by different methods. 23,[25][26][27][28][29][30][31][32][33][34][35][36] Several studies reported greater marginal discrepancies in restorations fabricated by the CAD/CAM systems, 23,[25][26][27][28][29] while others showed greater values in restorations made by conventional methods, [30][31][32][33] or even reported no significant differences 34 (►Table 1). The present study aimed to compare the marginal discrepancy of single implant-supported frameworks fabricated by different materials, using additive conventional/computerized and subtractive computerized methods.…”

Section: Introductionmentioning

confidence: 99%

Marginal Discrepancy of Single Implant-Supported Metal Copings Fabricated by Various CAD/CAM and Conventional Techniques Using Different Materials

2019

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Objective Framework patterns can be formed using various materials such as wax, acrylic resin, or composite. Frameworks can be fabricated using either conventional or computerized techniques, using additive or subtractive method. This study aimed to compare the marginal adaptation of metal copings fabricated by two computerized technologies (milling and rapid prototyping) and additive conventional methods using different materials. Materials and Methods Seventy-two fixture analogs were mounted vertically in acrylic resin. One-piece abutments with 5.5 mm in length and 6 degrees of convergence were secured into the analogs. The experimental frameworks were fabricated using either subtractive CAD/CAM milling (by wax, soft or hard metal), additive rapid prototyping (by wax), or conventional pattern fabrication (by wax [control] or acrylic resin). Wax and acrylic resin patterns were casted in Ni-Cr alloy. Marginal discrepancy was measured in 12 points by video measuring machine. Statistical Analysis One-way ANOVA and posthoc tests were used to detect any significant difference among the groups at α= 0.05. Results There was a statistically significant difference among the marginal discrepancy of six groups (p = 0.018). The Tukey test indicated a significant difference between CAD/milling of soft metal and conventional wax pattern groups (p = 0.011); a significant difference was also reported between CAD/milling of wax patterns and control group (p = 0.046). Conclusions Frameworks fabricated by conventional wax-up showed the largest marginal gaps, while the marginal gap created by frameworks made of soft metal CAD/milling were the smallest. In addition, frameworks fabricated by rapid prototyping showed clinically acceptable adaptations.

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Marginal discrepancy dimensions of single unit metal crowns fabricated by using CAD-CAM–milled acrylate resin polymer blocks or a conventional waxing technique

Cited by 7 publications

References 16 publications

Comparison of the Internal fit of conventional casting versus CAD wax (In-vitro Study)

Comparison of the Internal fit of conventional casting versus CAD wax (In-vitro Study)

Assessment of internal fit and micro leakage of conventionally fabricated ceramometallic restoration versus CAD wax and press veneering (in-vitro study)

Marginal Discrepancy of Single Implant-Supported Metal Copings Fabricated by Various CAD/CAM and Conventional Techniques Using Different Materials

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