Evaluation of marginal and internal gaps of Ni-Cr and Co-Cr alloy copings manufactured by microstereolithography

Dong Yeon Kim, Chong Myeong Kim, Ji Hwan Kim, Hae Young Kim, Woong Chul Kim

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


PURPOSE. The purpose of this study was to evaluate the marginal and internal gaps of Ni-Cr and Co-Cr copings, fabricated using the dental μ-SLA system. MATERIALS AND METHODS. Ten study dies were made using a twostep silicone impression with a dental stone (type IV) from the master die of a tooth. Ni-Cr (NC group) and Co-Cr (CC group) alloy copings were designed using a dental scanner, CAD software, resin coping, and casting process. In addition, 10 Ni-Cr alloy copings were manufactured using the lost-wax technique (LW group). The marginal and internal gaps in the 3 groups were measured using a digital microscope (160 ×) with the silicone replica technique, and the obtained data were analyzed using the non-parametric Kruskal-Wallis H test. Post-hoc comparisons were performed using Bonferroni-corrected Mann-Whitney U tests (α=.05). RESULTS. The mean (± standard deviation) values of the marginal, chamfer, axial wall, and occlusal gaps in the 3 groups were as follows: 81.5±73.8, 98.1±76.1, 87.1±44.8, and 146.8±78.7 μm in the LW group; 76.8±48.0, 141.7±57.1, 80.7±47.5, and 194.69±63.8 μm in the NC group; and 124.2±52.0, 199.5±71.0, 67.1±37.6, and 244.5±58.9 μm in the CC group. CONCLUSION. The marginal gap in the LW and NC groups were clinically acceptable. Further improvement is needed for CC group to be used clinical practice.

Original languageEnglish
Pages (from-to)176-181
Number of pages6
JournalJournal of Advanced Prosthodontics
Issue number3
Publication statusPublished - 2017 Jun 1

Bibliographical note

Funding Information:
This study was supported by Korea University Grant (k1605401).

Publisher Copyright:
© 2017 The Korean Academy of Prosthodontics.


  • Cobalt-chromium
  • Internal gap
  • Marginal gap

ASJC Scopus subject areas

  • Oral Surgery
  • Dentistry (miscellaneous)


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