Internal evaluation of provisional restorations according to the dental CAD/CAM manufacturing method : Three-dimensional superimpositional analysis

치과 CAD/CAM 가공방식에 따른 임시보철물의 내면 적합도 : 3차원 중첩 분석

  • Kim, Jae-Hong (Department of Dental Laboratory Science, College of Health Science, Catholic University of Pusan) ;
  • Kim, Ki-Baek (Department of Dental Lab Technology, Daejeon Health Institute of Technology)
  • 김재홍 (부산가톨릭대학교 보건과학대학 치기공학과) ;
  • 김기백 (대전보건대학교 치기공과)
  • Received : 2019.04.26
  • Accepted : 2019.06.13
  • Published : 2019.06.30


Purpose: The purpose of the present study was to compare the internal fit of two different temporary restorations fabricated by dental CAD/CAM system and to evaluate clinical effectiveness. Methods: Composite resin tooth of the maxillary first molar was prepared as occlusal reduction(2.0mm), axial reduction(1mm offset), vertical angle(6 degree) and chamfer margin for a temporary crown and duplicated epoxy die was fabricated. The epoxy dies were used to fabricate provisional restorations by CAD/CAM milling technique or 3D-printing technique. The inner data from all crowns were superimposed on the master die file in the 'best-fit alignment' method using 3D analysis software. Statistical analysis was performed using a Wilcoxon's rank sum test for differences between groups. Results: It showed that the internal RMS(Root Mean Square) values of the additive group were significantly larger than those of other group. No significant differences in internal discrepancies were observed in the temporary crowns among the 2 groups with different manufacturing method. Conclusion: All the groups had the internal fit within the clinical acceptable range (< $50{\mu}m$). The continuous research in the future to be applied clinically for the adaptation of additive manufacturing technique are needed.


Additive manufacturing;Dental CAD/CAM;Internal evaluation;Provisional crown;Subtractive manufacturing

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Figure 1. Titanium abutment model

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Figure 2. CAM procedures to fabricate provisional restoration

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Figure 4. Three-dimensional deviation of single provisional restoration of color difference map

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Figure 3. . Flowchart over the experimental protocol

Table 1. Mean±SD discrepancy between the stone replica(CRM) and the silicone replica

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