Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems.
- Author:
Jong Kyoung PARK
1
;
Wan Sun LEE
;
Hae Young KIM
;
Woong Chul KIM
;
Ji Hwan KIM
Author Information
- Publication Type:Original Article
- Keywords: CAD/CAM system; Cobalt-chromium alloy; Computer-aided milling; Direct metal laser sintering; Marginal and internal fit
- MeSH: Replica Techniques; Silicones
- From:The Journal of Advanced Prosthodontics 2015;7(2):122-128
- CountryRepublic of Korea
- Language:English
- Abstract: PURPOSE: To assess the marginal and internal gaps of the copings fabricated by computer-aided milling and direct metal laser sintering (DMLS) systems in comparison to casting method. MATERIALS AND METHODS: Ten metal copings were fabricated by casting, computer-aided milling, and DMLS. Seven mesiodistal and labiolingual positions were then measured, and each of these were divided into the categories; marginal gap (MG), cervical gap (CG), axial wall at internal gap (AG), and incisal edge at internal gap (IG). Evaluation was performed by a silicone replica technique. A digital microscope was used for measurement of silicone layer. Statistical analyses included one-way and repeated measure ANOVA to test the difference between the fabrication methods and categories of measured points (alpha=.05), respectively. RESULTS: The mean gap differed significantly with fabrication methods (P<.001). Casting produced the narrowest gap in each of the four measured positions, whereas CG, AG, and IG proved narrower in computer-aided milling than in DMLS. Thus, with the exception of MG, all positions exhibited a significant difference between computer-aided milling and DMLS (P<.05). CONCLUSION: Although the gap was found to vary with fabrication methods, the marginal and internal gaps of the copings fabricated by computer-aided milling and DMLS fell within the range of clinical acceptance (<120 microm). However, the statistically significant difference to conventional casting indicates that the gaps in computer-aided milling and DMLS fabricated restorations still need to be further reduced.
