Comparative Evaluation of Fracture Resistance/Strength of Interim Prosthesis for Crown and FDPs Using Conventional and Digital Methods: A Systematic Review and Meta-Analysis

Abstract

Introduction: Interim prostheses play a vital role in protecting, stabilizing, and guiding treatment outcomes in restorative dentistry. The evolution of digital workflows, particularly 3D printing and CAD/CAM milling, has introduced new fabrication techniques for provisional restorations. However, there is ongoing debate over whether digital methods yield higher fracture resistance than conventional ones.

Objectives:  This systematic review and meta-analysis aimed to compare the fracture resistance/strength of interim prostheses fabricated by 3D printing, CAD/CAM milling, and conventional methods.

Methods:  A comprehensive literature search was performed across PubMed, Scopus, Web of Science, Google Scholar, and Cochrane Library databases for studies conducted from 2010 to 2024. Studies included in vitro or clinical human research directly comparing fracture resistance of 3D-printed, CAD/CAM-milled, and conventional interim crowns/FDPs. Risk of bias was assessed using Cochrane collaboration tools.

Results: Of 896 initial studies, 8 met the inclusion criteria. Meta-analysis showed that 3D-printed PMMA provisional restorations exhibited significantly higher fracture strength than conventional PMMA (SMD = 1.41 [0.74, 2.08], p < 0.0001, I² = 87%). Comparisons between 3D-printed and CAD/CAM-milled PMMA revealed no significant difference in fracture resistance (SMD = 0.27 [-0.13, 0.66], p = 0.18, I² = 93%). Similarly, while 3D-printed PMMA tended to outperform bis-acrylic resins, the difference was not statistically significant (SMD = 0.45 [-0.06, 0.96], p = 0.12, I² = 85%).

Conclusions: 3D-printed PMMA-based interim prostheses demonstrate superior fracture resistance compared to conventional PMMA and bis-acrylic resins. However, evidence regarding their superiority over CAD/CAM-milled PMMA remains inconclusive.