Effect of Net Fiber Reinforcement Surface Treatment on Soft Denture Liner Retention and Longevity

Purpose: To evaluate shear bond strength of Molloplast‐B soft liner attached to different acrylic surfaces (smooth, rough, and Sticktech net fiber‐reinforced interfaces) after 3000 thermal cycles. Materials and Methods: Sixty‐nine specimens were fabricated by attaching Molloplast‐B soft liner to acrylic bases of three interfaces (n= 23); smooth (Group 1, control), rough (Group 2), and Sticktech net fiber‐reinforced interface (Group 3). The specimens underwent 3000 thermocycles (5 and 55°C) before being subject to a shear bond test at 2 mm/min crosshead speed. Debonding sites were investigated using an optical microscope at 40× magnification. Bond failures were categorized as adhesive, cohesive, or mixed. Results: Mean (SD) bond strength values (MPa) were: 0.71 (0.15); 0.63 (0.07); and 0.83 (0.12) for smooth, rough, and fiber‐reinforced acrylic interfaces, respectively. The mean values were analyzed using one‐way ANOVA and Bonferroni post hoc test for pairwise comparisons (p≤ 0.05). The net fiber‐reinforced acrylic interface exhibited a statistically significantly higher bond strength value when compared to smooth and rough acrylic interfaces (P= 0.003 and P= 0.000, respectively). Modes of failure were mainly cohesive (91%), followed by mixed failures (9%). Conclusions: Molloplast‐B exhibited a stronger bond to StickTech Net fiber‐reinforced surfaces when compared to smooth and rough acrylic interfaces after thermocycling. This may enhance prosthesis serviceability during clinical use.     

Effects of Accelerated Artificial Daylight Aging on Bending Strength and Bonding of Glass Fibers in Fiber‐Embedded Maxillofacial Silicone Prostheses

Purpose: The purpose of this study was to test the effect of different periods of accelerated artificial daylight aging on bond strength of glass fiber bundles embedded into maxillofacial silicone elastomer and on bending strength of the glass fiber bundles. Methods and Materials: Forty specimens were fabricated by embedding resin‐impregnated fiber bundles (1.5‐mm diameter, 20‐mm long) into maxillofacial silicone elastomer. Specimens were randomly allocated into four groups, and each group was subjected to different periods of accelerated daylight aging as follows (in hours); 0, 200, 400, and 600. The aging cycle included continuous exposure to quartz‐filtered visible daylight (irradiance 760 W/m²) under an alternating weathering cycle (wet for 18 minutes, dry for 102 minutes). Pull‐out tests were performed to evaluate bond strength between fiber bundles and silicone using a universal testing machine at 1 mm/min crosshead speed. Also a three‐point bending test was performed to evaluate bending strength of the fiber bundles. One‐way ANOVA and Bonferroni post hoc tests were carried out to detect statistical significance (p < 0.05). Results: Mean (SD) values of maximum pull‐out forces (in N) for groups 1 to 4 were: 13.63 (7.45), 19.67 (1.37), 13.58 (2.61), and 10.37 (2.52). Group 2 exhibited the highest pull‐out force that was statistically significant when compared to the other groups. Maximum bending strengths of fiber bundles were in the range of 917.72 MPa to 1124.06 MPa. Bending strength significantly increased after 200 and 400 hours of aging only. Conclusions: After 200 hours of exposure to artificial daylight and moisture conditions, bond strength between glass fibers and heat‐cured silicones is optimal, and the bending strength of the glass fiber bundles is enhanced.     

Screw-Retained Prosthesis for Straumann Implant Sites with Limited Interocclusal Clearance

This article reports a technique that addresses the problem of the restricted interocclusal distance when screw-retained prostheses are selected.