[Effectiveness of methacrylamide monomer for dentin bonding].
OBJECTIVE
In this study, we investigated the conditioning efficacy of a self-etching primer consisting of methacrylamide, N-methacryloyl-omega-amino acid (M omega A) derivatives for enhancing the bond strength of resin to crown and root dentins.


METHODS
A series of four M omega A derivatives, with different methylene chain numbers, were synthesized, as follows. 1: N-methacrylole glycine (Gly); 2: N-methacrylole-beta-alanine (beta Ala); 3: N-methacrylole-4-aminobutyric acid (Bu); 4: N-methacrylole-5-aminovaleric acid (Va). The dissociation equilibrium pH (pKa) of carboxylic acid in each of the M omega A derivatives was determined. The shear bond strengths of resin to the crown and root dentins, primed with the Gly solution were measured for various conditioning times. We also measured the bond strength to both the dentins following application of the M omega A adhesives with different pKa values for 30 seconds.


RESULTS
For the Gly primer, the bond strength of resin to both dentins increased with the conditioning time until 30 seconds, leveled off thereafter by increase in the methylene chain number. The effects of conditioning time on the bond strength to the crown and the root dentin were the same. Furthermore, the bond strengths to the dentins, conditioned with each of the four M omega A derivatives for 30 seconds, were the same, even though the decalcified amounts of the dentin apatite noted following conditioning with Bu and Va were lower than that noted following conditioning with Gly. This was attributed to the pKa value of the acidic groups in the acidic monomer directly relating to the decalcified amount of dentin apatite.


CONCLUSIONS
Application of the M omega A solutions, resulted in an increase in the bond strength of resin to both crown and root dentins. In particular, the Bu and Va primers were very useful as primers promoting the bond of resin to dentin, since the etching potential was very low.
Aida
Masahiro
M
Department of Crown Bridge Prosthodontics, Nihon University School of Dentistry at Matsudo. aida.masahiro@nihon-u.ac.jp
Odaki
Misako
M
Nishiyama
Norihiro
N
Masuda
Mikiko
M
Teramoto
Ichiro
I
Nemoto
Kimiya
K
D000178:Acrylamides / Q000138:chemical synthesis; D002264:Carboxylic Acids; D003442:Crowns; D001840:Dental Bonding; D045662:Dental Etching; D003804:Dentin; D017220:Dentin-Bonding Agents; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019279:Resin Cements; D033081:Shear Strength; D019231:Tooth Preparation, Prosthodontic
D000178:Acrylamides; D002264:Carboxylic Acids; D017220:Dentin-Bonding Agents; D019279:Resin Cements; C045985:methacrylamide