Fracture Force, Deflection, and Toughness of Acrylic Denture Repairs Involving Glass Fiber Reinforcement

• Published in: Journal of prosthodontics 2008-06, Vol.17 (4), p.257-261
• Main Authors: Kostoulas, Ioannis, Kavoura, Victoria T., Frangou, Mary J., Polyzois, Gregory L.
• Format: Article
• Language: English
• Subjects: Acrylic Resins - chemistry; Dental Materials - chemistry; Dentistry; Denture Bases; Denture Repair; dentures; Glass - chemistry; Glass fibers; Humans; Materials Testing; Methylmethacrylate - chemistry; Methylmethacrylates - chemistry; Pliability; Polymethyl Methacrylate - chemistry; Polyurethanes - chemistry; repair; Stress, Mechanical; Temperature; Time Factors; Water - chemistry
• ISSN: 1059-941X; 1532-849X
• DOI: 10.1111/j.1532-849X.2007.00276.x

Purpose: Fractures in acrylic resin dentures occur quite often in the practice of prosthodontics. A durable repairing system for denture base fracture is desired to avoid recurrent fracture. The purpose of this study was to evaluate the fracture force, deflection, and toughness of a heat‐polymerized denture base resin repaired with autopolymerized resin alone (C), visible light‐polymerizing resin (VLC), or autopolymerizing resin reinforced with unidirectional (Stick) (MA‐FS) and woven glass fibers (StickNet) (MA‐SN). Another group was repaired with autopolymerized resin after wetting the repair site with methyl methacrylate (MA‐MMA) for 180 seconds. A group of intact specimens was used as control. Materials and Methods: Heat‐polymerizing acrylic resin was used to fabricate the specimens. The specimens (10 per group) were sectioned in half, reassembled with a 3‐mm butt‐joint gap, and repaired. A cavity was included when glass fibers were used. Three‐point bending was used to test the repaired site, and data were analyzed with one‐way ANOVA and the Tukey's post hoc test (α≤ 0.05). Results: Fracture force, deflection, and toughness for the repaired groups without reinforcement (MA: 46.7 ± 8.6 N, 2.6 ± 0.3 mm, 0.08 ± 0.001 J; MA‐MMA: 41.0 ± 7.2 N, 2.7 ± 0.4 mm, 0.07 ± 0.002 J) were significantly lower (p < 0.05) than the control group (C: 78.6 ± 9.6 N, 5.9 ± 0.4 mm, 0.27 ± 0.003 J). Repair with visible light‐polymerizing resin (VLC, 15.0 ± 4.0 N, 1.2 ± 0.4 mm, 0.02 ± 0.0001 J) resulted in significant reduction of mechanical properties (p < 0.05). Reinforcement with glass fibers restored (MA‐SN: 75.8 ± 9.2 N) or increased (MA‐FS: 124.4 ± 12.5 N) the original strength. Conclusion: The most effective repair method was the use of autopolymerized resin reinforced with unidirectional glass fibers.