Reza Eftekhar Ashtiani1, Leila Nasiri Khanlar2, Minoo Mahshid3, Alireza Moshaverinia4. 1. Assistant Professor and Chair, School of Dental Technology, Shahid Beheshti University of Medical Science, Tehran, Iran. Electronic address: afshin1q@gmail.com. 2. Assistant Professor, Operative Dentistry Department, School of Dentistry, Shahid Beheshti University of Medical Science, Tehran, Iran. 3. Professor, Department of Prosthodontics, Dental School, Shahid Beheshti University of Medical Science, Tehran, Iran. 4. Assistant Professor, Division of Advanced Prosthodontics, UCLA School of Dentistry, Los Angeles, Calif.
Abstract
STATEMENT OF PROBLEM: Advances have been made in digital dentistry for the fabrication of dental prostheses, but evidence regarding the efficacy of digital techniques for the fabrication of intracoronal restorations is lacking. PURPOSE: The purpose of this in vitro study was to compare the dimensional accuracy of intracoronal restorations fabricated with digital and conventional techniques. MATERIAL AND METHODS: A sound mandibular molar tooth received a standard onlay preparation, and onlays were fabricated with 1 of 3 fabrication techniques. In group CC, the onlays were made after conventional impression and conventional fabrication of a resin pattern. In group CP, the onlays were made after conventional impression and 3-dimensional (3D) printing of the pattern. In group IP, the onlays were made after intraoral scanning, and 3D printing produced the resin pattern. Ten specimens in each group (N=30) were evaluated. Glass-ceramic restorations were fabricated using the press technique. The replica technique was used to assess the marginal fit. Each replica was assessed at 8 points. One-way ANOVA was used to compare the marginal discrepancy among the 3 groups. The Tukey honest significant differences test was applied for pairwise comparisons of the groups (α=.05). RESULTS: No significant differences were noted in the marginal discrepancy at the gingival margin among the 3 groups (P=.342), but significant differences were noted among the 3 groups in the pulpal (P=.025) and lingual (P=.031) areas. Comparison of the absolute discrepancy among the 3 groups revealed that only groups CC and CP were significantly different (P=.020) from each other. CONCLUSIONS: Within the limitations of this in vitro study, the conventional method yielded more accuracy than the 3D printing method, and no differences were found between the methods which used the 3D printer (groups CP and IP).
STATEMENT OF PROBLEM: Advances have been made in digital dentistry for the fabrication of dental prostheses, but evidence regarding the efficacy of digital techniques for the fabrication of intracoronal restorations is lacking. PURPOSE: The purpose of this in vitro study was to compare the dimensional accuracy of intracoronal restorations fabricated with digital and conventional techniques. MATERIAL AND METHODS: A sound mandibular molar tooth received a standard onlay preparation, and onlays were fabricated with 1 of 3 fabrication techniques. In group CC, the onlays were made after conventional impression and conventional fabrication of a resin pattern. In group CP, the onlays were made after conventional impression and 3-dimensional (3D) printing of the pattern. In group IP, the onlays were made after intraoral scanning, and 3D printing produced the resin pattern. Ten specimens in each group (N=30) were evaluated. Glass-ceramic restorations were fabricated using the press technique. The replica technique was used to assess the marginal fit. Each replica was assessed at 8 points. One-way ANOVA was used to compare the marginal discrepancy among the 3 groups. The Tukey honest significant differences test was applied for pairwise comparisons of the groups (α=.05). RESULTS: No significant differences were noted in the marginal discrepancy at the gingival margin among the 3 groups (P=.342), but significant differences were noted among the 3 groups in the pulpal (P=.025) and lingual (P=.031) areas. Comparison of the absolute discrepancy among the 3 groups revealed that only groups CC and CP were significantly different (P=.020) from each other. CONCLUSIONS: Within the limitations of this in vitro study, the conventional method yielded more accuracy than the 3D printing method, and no differences were found between the methods which used the 3D printer (groups CP and IP).