Marginal and internal fit evaluation of metal copings fabricated by selective laser sintering and CAD/CAM milling techniques: in-vitro study

Document Type : Original Article

Authors

1 Conservative Department, Fixed Prosthodontics division, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.

2 Professor, Department of Conservative Dentistry, Fixed Prosthodontics division, Faculty of Dentistry, Alexandria University.

3 Associate Professor, Department of Conservative Dentistry, Fixed Prosthodontics division, Faculty of Dentistry, Alexandria University.

Abstract

Introduction: Metal-ceramic restorations are still commonly used in dentistry. The success of these restorations depends mainly on the marginal integrity and the internal fit which in turn is affected by the technique of fabrication.
Aim of the study: Comparing the marginal and internal fit of metal copings manufactured using three different techniques.
Materials and method: A metal master die simulating a maxillary first molar preparation was fabricated. Thirty Vinyl poly siloxane impressions were prepared for the master die and poured to obtain 30 epoxy resin dies. The epoxy dies were allocated at random to 3 groups (n=10) following the method of metal copings fabrication. Group I: selective laser sintering technique (additive technique), group II: CAD-CAM milling technique (subtractive technique), group III: lost wax technique (control group). The marginal and internal fit was evaluated by the silicone replica technique. The data were analyzed by One Way ANOVA followed by multiple pairwise comparisons using Bonferroni adjustment.
Results: Group II had a significantly larger internal gap (33.60 µm) compared to group I (30.15 μm) and group III (27.83 μm) (P=0.03). No significant difference was found in the marginal fit.
Conclusions: Although Metal copings produced by the lost wax technique showed the best adaptation, all tested techniques resulted in clinically acceptable fit values.

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Alexandria Dental Journal
Volume 47, Issue 2
B (Endodontics, Prosthodontics, Fixed prosthodontics, Conservative dentistry, Dental Biomaterials)
August 2022
Pages 134-139

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