Adhesion of resin composite core materials to dentin.
OBJECTIVE
This study determined (1) the effect of polymerization mode of resin composite core materials and dental adhesives on the bond strength to dentin, and (2) if dental adhesives perform as well to dentin etched with phosphoric acid as to dentin etched with self-etching primer.


METHODS
Human third molars were sectioned 2 mm from the highest pulp horn and polished. Three core materials (Fluorocore [dual cured], Core Paste [self-cured], and Clearfil Photo Core [light cured]) and two adhesives (Prime & Bond NT Dual Cure and Clearfil SE Bond [light cured]) were bonded to dentin using two dentin etching conditions. After storage, specimens were debonded in microtension and bond strengths were calculated. Scanning electron micrographs of representative bonding interfaces were analyzed.


RESULTS
Analysis showed differences among core materials, adhesives, and etching conditions. Among core materials, dual-cured Fluorocore had the highest bond strengths. There were incompatibilities between self-cured Core Paste and Prime & Bond NT in both etched (0 MPa) and nonetched (3.0 MPa) dentin. Among adhesives, in most cases Clearfil SE Bond had higher bond strengths than Prime & Bond NT and bond strengths were higher to self-etched than to phosphoric acid-etched dentin. Scanning electron micrographs did not show a relationship between resin tags and bond strengths.


CONCLUSIONS
There were incompatibilities between a self-cured core material and a dual-cured adhesive. All other combinations of core materials and adhesives produced strong in vitro bond strengths both in the self-etched and phosphoric acid-etched conditions.
O'Keefe
K L
KL
Department of Restorative Dentistry, and Biomaterials Scientist, Houston Biomaterials Research Center, University of Texas-Houston Dental Branch, 6516 John Freeman Avenue, Houston, Texas 77030, USA. Kathy.L.Okeefe@uth.tmc.edu
Powers
J M
JM
D000134:Acid Etching, Dental / Q000379:methods; D000704:Analysis of Variance; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D005460:Fluorides, Topical / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D008964:Molar, Third; D010756:Phosphoric Acids / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013499:Surface Properties
C438313:Clearfil SE Bond; D003188:Composite Resins; C074317:Core Paste composite resin; D017220:Dentin-Bonding Agents; D005460:Fluorides, Topical; C074316:FluoroCore; D010756:Phosphoric Acids; D011108:Polymers; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; C074669:Clearfil Photo Bond