Effect of Relining Material and Channel Diameter on the Flexural Strength of Milled PMMA for Full Arch Immediate Interim Restorations: an in vitro study.

Description :

Summary: This in vitro study evaluates the impact of relining material type and channel diameter on the flexural strength of milled polymethyl methacrylate (PMMA) used in full-arch immediate interim restorations. By testing eight experimental groups, the study aims to determine the effect of these variables on the rigidity of PMMA to minimize micromovements that could compromise implant osseointegration. The findings aim to inform clinical guidelines for the pick-up process in implant prosthodontics. Methodology: Sample Preparation: 64 PMMA bars are milled from pre-polymerized blanks with two channel diameters (4.8 mm and 5.8 mm) and relined using four materials (auto-polymerizing PMMA, auto-polymerizing composite, dual-cure resin, and photo-polymerizing composite). Testing: Specimens undergo thermocycling (2,500 cycles) and are tested using a three-point bending setup on a universal testing machine to measure maximum load and flexural strength. Failures are classified as adhesive, cohesive, or mixed. Statistical Analysis: A two-way ANOVA is conducted to evaluate the effects of relining material and channel diameter on flexural strength, followed by post-hoc testing. This study provides insights into optimizing the pick-up technique to enhance the structural reliability of PMMA interim restorations.