Bonding of composite resin to dentin using rigid rod polymer modified primers.
OBJECTIVE
This study was conducted to evaluate the microtensile bond strength of composite resin to dentin with experimental rigid rod polymer (RRP) modified primers. RRP fillers are based on long stiff molecules specifically designed to create long polymers with restricted chain movement.


METHODS
Experimental primers were fabricated by dissolving RRP into dichloromethane (DCM) and further mixing it with monomers: ethylene glycol methacrylate phosphate (EGMP), bis[2-(methacryloyloxy)-ethyl]phosphate (BMEP) and 3(methacryloyloxy)propyltrimethoxysilane (MPS). Eight experimental primers were prepared with different proportions for each dentin substrate. A commercial etch-and-rinse adhesive was used as a control. Surfaces of human molar teeth were wet ground occlusally. The experimental primers were applied onto dentin prior to light polymerization of the incremental composite resin build-up. After 48 hours of water storage, teeth were sectioned and tested with the microtensile tester. Fracture surface analysis and contact angle measurements of adhesive resin were performed. Scanning electron micrographs were taken.


RESULTS
3-way ANOVA revealed that all factors, monomer type, solvent-monomer ratio and RRP, had a significant effect (p < 0.05) on bond strength. Primer with a combination of MPS and dimethacrylate BMEP revealed higher bond values than a mixture of MPS and monomethacrylate EGMP. Increase of the solvent-monomer ratio and addition of RRP into primers increased the microTBS.


CONCLUSIONS
The contact angle measurements showed that RRP containing primers enhanced adhesive resin penetration into dentin similar to that of the control primer. Within the limitations of this study, it was concluded that an experimental type of modified RRP-silane-phosphate-acrylate primer was developed with comparable bonding properties to a commercial control.
Department of Prosthetic Dentistry and Biomaterials, Institute of Dentistry, University of Turku, Turku, Finland. anmavu@utu.fi
Anne-Maria
AM
Vuorinen
Scott R
SR
Dyer
Pekka K
PK
Vallittu
Lippo V J
LV
Lassila
D000268:Adhesiveness; D000293:Adolescent; D000328:Adult; D003188:Composite Resins / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008752:Methylene Chloride / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D009943:Organophosphorus Compounds / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors; D014867:Water / Q000737:chemistry; D017155:Wettability; D055815:Young Adult
D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; C509998:Grandio; D008689:Methacrylates; D009943:Organophosphorus Compounds; D010710:Phosphates; D011108:Polymers; D019279:Resin Cements; D012821:Silanes; C488002:Solobond Plus adhesive; D012997:Solvents; C097098:di(2-methacryloyloxyethyl)phosphate; D014867:Water; C017492:methacryloxypropyltrimethoxysilane; D008752:Methylene Chloride; C508958:ethylene glycol methacrylate phosphate