Bond strength of soft liners to fiber-reinforced denture-base resin.
OBJECTIVE
This study evaluated bond strengths of four soft liners to fiber-reinforced (FR) and unreinforced poly methyl(methacrylate) (PMMA) denture-base resin.


METHODS
The autopolymerized denture-base resin Palapress Vario (Heraus Kulzer GmbH, Hanau, Germany) was used as the substrate (15 × 15 × 5 mm³). The test group consisted of substrates reinforced with porous PMMA preimpregnated unidirectional glass fibers (Stick [StickTech, Turku, Finland]) (PMMA + FR group), and the control group was unreinforced acrylic resin (PMMA group) (n = 80 per group). One of four soft liners (Ufi Gel SC [Voco, Cuxhaven, Germany], Sofreliner Tough [Tokuyama Dental Corporation, Tokyo, Japan], Vertex SoftSil 25 [Vertex-Dental B.V., Zeist, The Netherlands], and Eversoft [Dentsply Austenal, York, PA]) was placed and cured between two substrates using a polyethylene ring (10 mm inner radius, 3 mm height). Tensile bond strength tests (crosshead speed = 10 mm/min) were performed, and the results were analyzed using analysis of variance followed by Tukey's test (p= 0.05). Fracture surfaces were categorized as adhesive or cohesive-mixed modes, and failure types were statistically analyzed using chi-square test.


RESULTS
FR did not affect the bond strength results significantly (p > 0.05) except for Ufi Gel SC. Significant differences in bond strength were found among the reline materials (p < 0.001). FR specimens showed a significantly higher number of cohesive-mixed fractures compared to unreinforced specimens (p < 0.05), except for plasticized acrylic-based reline material (Eversoft [Dentsply Austenal]), which showed fewer cohesive-mixed failures with FR.


CONCLUSIONS
The choice of appropriate reline material system with FR acrylic resin is important for the soft liner/denture-base polymer bond. Glass FR did not have a decreasing effect on the bond strength, except for Ufi Gel SC.
Department of Biomaterials Science, Institute of Dentistry, University of Turku, Turku, Finland.
Lippo V J
LV
Lassila
M Murat
MM
Mutluay
Arzu
A
Tezvergil-Mutluay
Pekka K
PK
Vallittu
D000180:Acrylic Resins / Q000737:chemistry; D000268:Adhesiveness; D000465:Algorithms; D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003819:Denture Bases; D003822:Denture Liners; D055119:Elastic Modulus; D005898:Glass / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012826:Silicone Elastomers / Q000737:chemistry; D013314:Stress, Mechanical; D013718:Tensile Strength
D000180:Acrylic Resins; D003764:Dental Materials; C507521:Palapress Vario; D012826:Silicone Elastomers; C485628:Stick resin; C483158:Ufi gel; C076426:Vertex Soft; C009753:fiberglass; C501646:tokuyama soft relining; D019904:Polymethyl Methacrylate