Effect of Fabrication Technique and Margin Design on the Marginal Fit of Interim Fixed Dental Prosthesis (An In-Vitro Study)

Kheir, Mohamad Kheir Jihad; Younis, Jihan Farouk; Mokhtar, Ashraf

doi:10.21608/jfcr.2023.226432.1052

Effect of Fabrication Technique and Margin Design on the Marginal Fit of Interim Fixed Dental Prosthesis (An In-Vitro Study)

Document Type : Original research articles

Authors

¹ Department fixed prosthodontics, Misr International University

² Professor of Fixed Prosthodontics, Fixed Prosthodontics Department, Faculty of Dentistry, Cairo University, Cairo, Egypt.

³ Fixed prosthodontics department, Dentistry, Cairo University, Cairo, Egypt.

10.21608/jfcr.2023.226432.1052

Abstract

Background: There is limited evidence available regarding the effectiveness of various digital manufacturing techniques for producing interim prosthesis with different finish line designs. Aim: The objective was to evaluate the influence of CAM techniques, 3D printed and milled on the vertical margin gap of interim fixed dental prosthesis using two finish line designs. Materials and Methods: Two prepared abutment teeth were designed with finish line designs (shoulder and knife-edge) to receive a 3-unit interim prosthesis (polymethyl methacrylate and microfilled hybrid resin). The reference models were 3D printed (n=28), and an optical impression was performed to design FDPs on CAD software. Group A milled with shoulder finish line. Group B milled with knife-edge finish line. Group C 3D-printed with shoulder finish line. Group D 3D-printed with knife-edge finish line. Samples were cemented with long-term temporary cement. Vertical marginal fit was assessed using stereo-optical microscope before and after thermocycling Results: Marginal gaps in both techniques were influenced by thermocycling. The knife-edge finish line showed a higher gap when milled. Overall gap distance for 3D-printed knife-edge and shoulder finish line before (20-74.8 µm, 17.8-91µm) and after thermocycling (34-103µm, 33-112µm). Overall gap distance for milled knife-edge and milled finish lines before (43-111.8 µm, 17.2-93µm) and after thermocycling (62-141 µm, 27-103µm). Conclusion: Thermocycling showed a negative effect on vertical marginal adaptation in both techniques. Vertical marginal gap of the interim restorations fabricated by the two techniques was within the acceptable clinical range of ≤120μm.

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