A comparative evaluation of flexural strengths of two different chairside repair materials with and without modification of implant attachment housings: An in vitro study

Statement of Problem: Implant overdentures become thinner and weaker after direct transfer of implant attachment housings. The introduction of a metal housing changes the character of the repair as denture has to be relieved to provide space for the housings; therefore, a strong method of repair is desirable to avoid prosthesis fracture. Purpose: The purpose of this study was to compare flexural strength of two different chairside repair materials with and without modification of implant attachment housings. Materials and Methods: Eighty 13 mm × 10 mm × 41 mm heat-polymerized acrylic resin blocks were processed, assessed for porosities, and polished. An 8.5-mm diameter hole was created to a depth of 5 mm in the center of each block. Two different attachment housings sandblasted and nonsandblasted were placed into the blocks with two different repair materials: autopolymerized acrylic resin (APAR) and light-polymerized acrylic resin. Later blocks were immersed in water for 7 days in an incubator. A three-point bend test was done in a universal testing machine, and load to fracture was recorded (MPa). Results were compared with one-way analysis of variance (α = 0.05). Results: The mean maximum strength of APAR groups was significantly higher than light-polymerized acrylic resin groups. Groups with sandblasted attachment housings showed significantly higher strength compared to nonsandblasted groups. Conclusions: The flexural strength of self-cured acrylic resin with and without sandblasting of attachment was significantly higher than light-cured acrylic resin with and without sandblasting of attachment housings. Sandblasting produced higher flexural strength in denture blocks repaired with self-cured acrylic.