Effect of Phenyl-P/HEMA acetone primer on wet bonding to EDTA-conditioned dentin.
OBJECTIVE
The purpose of this study was to examine the effect of 2-methacryloyloxyethyl phenyl phosphoric acid (Phenyl-P)/2-hydroxyethyl methacrylate (HEMA) acetone-based primer on moist dentin surfaces that were preconditioned with ethylenediaminetetraacetate (EDTA) to remove the smear layer.


METHODS
Bovine dentin were prepared with 180-grit paper, conditioned with 0.5M EDTA (pH 7.4) for 60s followed by water rinsing and then blot drying. Each surface was then primed with Phenyl-P/30 wt% HEMA in acetone for 10s followed by blot drying. A light-cured bonding agent was then applied, cured and trimmed to give dumbbell-shaped specimens. The Phenyl-P concentration ranged from 1 to 20 wt%. During the bonding procedure, no compressed air was used. After storage in water at 37 degrees C for one day, tensile bond strengths were measured and analyzed using one-way ANOVA. Dentin discs treated under the same conditions were observed under a scanning electron microscope (SEM).


RESULTS
When the concentration of Phenyl-P was 12 wt%, the highest mean tensile bond strength was obtained (27 MPa). It was significantly higher than that of the 3, 5, 15 or 20 wt% groups (9-11 MPa) (p<0.05). The samples of 1 wt% group were all broken during trimming the dumbbell-shaped specimens. SEM observations showed a 1 microm-thick layer of hybridized dentin after polished cross-sections were chemically challenged with 6N HCl for 30s and then 1% NaOCl for 60 min.


CONCLUSIONS
The experimental Phenyl-P/HEMA acetone primer is effective in bonding resin to EDTA-conditioned dentin. Acetone as a solvent for Phenyl-P/HEMA primer has the clinical advantage of not requiring an air-stream to evaporate the solvent. The experimental bonding procedure can minimize the skin irritation by HEMA.
Miyasaka
K
K
Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan. miyasaka@i-mde.tmd.ac.jp
Nakabayashi
N
N
D000096:Acetone / Q000737:chemistry; D000134:Acid Etching, Dental; D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D001840:Dental Bonding; D003804:Dentin / Q000187:drug effects; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry / Q000494:pharmacology; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009943:Organophosphorus Compounds / Q000737:chemistry*; D016369:Smear Layer; D013499:Surface Properties; D013718:Tensile Strength
C400042:2-methacryloyloxyethyl phenyl phosphoric acid; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D009943:Organophosphorus Compounds; D000096:Acetone; C005044:hydroxyethyl methacrylate; D004492:Edetic Acid