Reinforcement for Overdentures on Abutment Teeth

• Published in: Nihon Hotetsu Shika Gakkai Zasshi Vol. 50; no. 2; pp. 191 - 199
• Main Author: Osada, Tomoko
• Format: Journal Article
• Language: Japanese
• Published: Japan Japan Prosthodontic Society 01.04.2006
• Subjects: Acrylic Resins; breaking strength; Composite Resins; coping; Dental Abutments; Denture, Overlay; framework design; Orthodontic Wires; overdenture; Prosthesis Design; reinforcement; Stress, Mechanical
• ISSN: 0389-5386; 1883-177X
• DOI: 10.2186/jjps.50.191

Purpose: This study investigated the effect of the position of reinforcement wires, differences in artificial teeth, and framework designs on the breaking strength of overdentures. Methods: The basal surfaces of composite resin teeth and acrylic resin teeth were removed using a carbide bur. A reinforcement wire or a wrought palatal bar was embedded near the occlusal surface or basal surface. Four types of framework structures were designed: conventional skeleton (skeleton), housing with skeleton (housing), housing plus short metal backing (metal backing), and housing plus long metal backing (double structure). After the wires, bars, and frameworks were sand-blasted with 50μm Al203 powder, they were primed with a metal primer and embedded in a heat-polymerized denture base resin. The breaking strengths (N) and maximum stiffness (N/mm) of two-week aged (37deg;C) specimens were measured using a bending test (n=8). All data obtained at a crosshead speed of 2.0mm/min were analyzed by ANOVA/Tukey's test (α=0.01). Results: There were no statistical differences between the two kinds of artificial teeth (p>0.01). The wrought palatal bar had significantly higher strength than the reinforcement wire (p<0.01). Greater strengths were found for specimens with frameworks than those without frameworks (p<0.01). The breaking strength of the wrought palatal bar embedded near the occlusal surface was higher than that on the basal surface (p>0.01). The breaking strength and maximum stiffness of the double structure framework were significantly greater (p<0.01) than those of the conventional frameworks. Conclusion: The breaking strengths of overdentures were influenced by the size and position of the reinforcement wires. Double structure frameworks are recommended for overdentures to promote a longterm prognosis without denture breakage.