Related Experiment Video
Updated: May 28, 2025
Quasistatic Mechanical Testing for Computer-Aided Design and Manufacturing Occlusal Veneers Cemented to Milled Dentin Analog Material
Published on: December 20, 2024
Effects of different fabrication techniques on the marginal gap of interim crowns as assessed by optical coherence
Siti Rosma Rosli1, Nur Diyana Mohamed Radzi2, Mohd Azmi Abdul Razak2
1Postgraduate student, Department of Restorative Dentistry, Faculty of Dentistry, Universiti Malaya, Kuala Lumpur, Malaysia.
Statement Of Problem:
Studies on the assessment of the marginal fit of interim crowns with optical coherence tomography (OCT) are lacking.
Purpose:
The purpose of this in vitro study was to apply OCT to evaluate and to compare the impact of conventional and computer-aided design and computer-aided manufacturing (CAD-CAM) fabrication methods and different materials, including bis-acryl, conventional polymethyl-methacrylate (PMMA), and CAD-CAM PMMA, on the marginal fit of interim crowns.
Material And Methods:
Thirty crown specimens were fabricated, with 20 PMMA crowns divided into 2 groups based on the fabrication method: the conventional method (Group Jet, n=10) and the CAD-CAM method (Group CAD-CAM PMMA, n=10). An additional 10 bis-acryl crowns were fabricated using the conventional method (Group Protemp, n=10). The marginal gap was assessed at 8 specific points using swept-source OCT. Comparisons between the fabrication methods of PMMA crowns and different materials of conventionally made crown were done using an independent t test (α=.05).
Results:
Group CAD-CAM PMMA recorded statistically significant lower total mean vertical marginal gap values (22.2 ±4.7 µm) compared with group Jet (62.6 ±2.2 µm) (P<.001). Among the conventional interim material, Group Protemp showed significantly lower values (57.6 ±5.2 µm) compared with group Jet (62.6 ±2.2 µm) (P=.02).
Conclusions:
The CAD-CAM fabrication method presented smaller marginal gaps. Among the conventional interim crown materials, bis-acryl showed smaller marginal gaps than PMMA.
