Effect of self-etching primer containing N-acryloyl aspartic acid on enamel adhesion.
OBJECTIVE
A previous study demonstrated that N-acryloyl aspartic acid (N-AAsp) aqueous solution is useful as a self-etching primer for dentin adhesion. The purpose of this study was to evaluate whether N-AAsp solution can be used for enamel etching, when compared with phosphoric acid.


METHODS
N-AAsp was synthesized by the reaction of DL-aspartic acid and acryloyl chloride. The experimental self-etching primers were prepared by dissolving N-AAsp in water at various concentrations up to 20 wt%. The tensile bond strength of resin to bovine enamel was measured after the enamel was treated with the N-AAsp primers. The 40 wt% H(3)PO(4) was used for comparison. The treated enamel surfaces and the resin-enamel interfaces were also observed with a scanning electron microscope.


RESULTS
The tensile bond strength to enamel increased linearly with the increasing N-AAsp concentration and reached the same value as that to enamel etched with 40 wt% H(3)PO(4) when N-AAsp concentration was 20 wt%, even though the etching ability of 20 wt% N-AAsp was inferior to 40 wt% H(3)PO(4). Regardless of the concentration of N-AAsp, the bond strength to enamel was the same as that to dentin reported in our previous study.


CONCLUSIONS
The 20 wt% N-AAsp aqueous solution showed enamel bonding equivalent to 40 wt% H(3)PO(4) in addition to the advantage of eliminating the rinse step with water. Based on the results obtained in this study along with those obtained in a previous study, it was concluded that 20 wt% N-AAsp aqueous solution is a promising self-etching primer to simultaneously treat enamel and dentin.
Torii
Yasuhiro
Y
Department of Operative Dentistry, Okayama University Dental School, 2-5-1 Shikata, Okayama 700-8525, Japan. torii@md.okayama-u.ac.jp
Itou
Kousuke
K
Nishitani
Yoshihiro
Y
Yoshiyama
Masahiro
M
Ishikawa
Kunio
K
Suzuki
Kazuomi
K
D000134:Acid Etching, Dental; D000704:Analysis of Variance; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002417:Cattle; D003743:Dental Enamel / Q000187:drug effects*; D003799:Dental Stress Analysis; D017220:Dentin-Bonding Agents; D016014:Linear Models; D008855:Microscopy, Electron, Scanning; D010756:Phosphoric Acids / Q000494:pharmacology; D019279:Resin Cements; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013718:Tensile Strength
D017220:Dentin-Bonding Agents; C412504:N-acryloylaspartic acid; D010756:Phosphoric Acids; D019279:Resin Cements; C074669:Clearfil Photo Bond; D001224:Aspartic Acid; C030242:phosphoric acid