Accuracy evaluation of metal copings fabricated by computer-aided milling and direct metal laser sintering systems

Jong Kyoung Park, Wan Sun Lee, Hae-Young Kim, Woong Chul Kim, Ji Hwan Kim

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14 Citations (Scopus)

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 (α=.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 μm). 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.

Original languageEnglish
Pages (from-to)122-128
Number of pages7
JournalJournal of Advanced Prosthodontics
Volume7
Issue number2
DOIs
Publication statusPublished - 2015

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Keywords

  • CAD/CAM system
  • Cobalt-chromium alloy
  • Computer-aided milling
  • Direct metal laser sintering
  • Marginal and internal fit

ASJC Scopus subject areas

  • Dentistry (miscellaneous)
  • Oral Surgery

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