The influence of fiber reinforcement of composites on shear bond strengths to enamel.
BACKGROUND
Fiber-reinforced composites (FRC) are used in direct intra-oral applications as periodontal splints and chairside tooth replacement by bonding them to etched enamel with resin adhesives and composites. There is little information regarding the effect of FRC on the shear bond strength of composite to etched enamel.


OBJECTIVE
The purpose of this study was to examine the effect of resin preimpregnated and non-preimpregnated fiber-reinforced composites on enamel to composite shear bond strength (SBS).


METHODS
Specimen groups (n = 12) consisted of a control (composite with no fiber reinforcement), Ribbond, Splint-It Unidirectional, Splint-It Woven, and Connect, which were bonded to 37% phosphoric acid etched Prime and Bond NT adhesive-treated bovine enamel surfaces on a bed of Tetric Flow composite. Specimens were thermocycled 1000 times between 5 degrees and 55 degrees C and loaded on a universal testing machine in shear at a linear increasing load until fracture (MPa). The fractured surfaces of the debonded specimens were evaluated to determine the nature of the fracture with a light binocular microscope (x10). Shear bond strength data were subjected to analysis of variance (ANOVA) and Student-Newman-Kuels tests (P <.05).


RESULTS
Mean MPa +/- SD for the test groups were as follows: Control, 15.6 +/- 2.4; Splint-It Unidirectional, 15.3 +/- 2.4; Splint-It Woven, 16.5 +/- 1.8; Connect, 18.8 +/- 1.5; and Ribbond, 15.8 +/- 2.2. The Connect FRC group had significantly higher (P <0.05) enamel SBS than all other groups. Fracture analysis showed varying types of failures among the groups, with cohesive fractures within the fiber reinforcement of Splint-It Unidirectional and Connect, cohesive fractures within the bonding resin/flowable composite for Ribbond and the control, and adhesive fracture at the fiber reinforcement interface with Splint-It Woven.


CONCLUSIONS
Within the limitations of this study, no differences in SBS were observed with the addition of 3 of the 4 FRCs compared to composite without FRC, with the exception of the Connect product which provided significantly higher SBS values.
Meiers
Jonathan C
JC
Department of Prosthodontics and Operative Dentistry, School of Dental Medicine, University of Connecticut, Farmington, Conn 06030-1370, USA. meiers@nso2.uchc.edu
Kazemi
Reza B
RB
Donadio
Marco
M
D000134:Acid Etching, Dental; D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure*; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011897:Random Allocation; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013816:Thermodynamics
D003188:Composite Resins; D003764:Dental Materials; D017220:Dentin-Bonding Agents; D011095:Polyethylenes; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; C084063:RIBBOND; C121818:Tetric ceram; C009753:fiberglass; C113549:splint-It, FRC material; C452226:tetric flow composite resin