Bond strengths of reline materials to two different denture polymers

Objectives: The aim of the study was to evaluate the shear bond strength (SBS) of three reline materials to a light-polymerized urethane dimethacrylate (UDMA) and a heat-polymerized polymethylmethacrylate (PMMA) denture base polymers.

Methods: Discs of UDMA (Eclipse) and PMMA (Meliodent) denture base polymers of 15mm diameter were bonded to two intra-oral (Secure & Kooliner) and one laboratory-processed (Meliodent RR) reline materials. Eclipse resin was finger adapted to the stone mould and polymerized for 10 minutes using visible light of 400-500nm wavelength. Meliodent specimens were polymerized for 7 hours at 70ºC and 1 hour at 100ºC. Relining was performed after 30 days water immersion. A brass ring (6mm internal diameter) was used to confine the reline material to standardized area on denture base specimens.  Ten additional Eclipse denture base specimens were prepared and relined using the same Eclipse resin. Shear bond test was carried out 24 hours after relining using an Instron machine at a crosshead speed of 1.0 mm/min. Data were analyzed using one-way ANOVA followed by Dunnett's T3 test (p=0.05).

Results: Shear bond strength (mean±S.D. in MPa); the same superscripts indicate no significant difference (p>0.05).

Conclusion: There was a significant difference in SBS values among denture base-reline material combinations (p<0.05) except for PMMA base-Kooliner and UDMA base-Meliodent RR reline combinations.