Efficacy of self-etching primers in the adhesion of 4-META/MMA-TBB resin cement to enamel.
OBJECTIVE
The effect of self-etching primer on the adhesion of tri-n-butylborane (TBB)-initiated resin cement to enamel has not been determined. This study evaluated the effectiveness of the self-etching primer by measuring the tensile bond strength between enamel and TBB-initiated methyl methacrylate (MMA) resin containing 4-methacryloxyethyl trimellitate anhydride (4-META).


METHODS
The self-etching primers were an aqueous mixture of 30 wt% methacryloxyethyl phosphate, 35 wt% 2-hydroxyethyl methacrylate, and ferric chloride. The concentration of ferric chloride was varied from 0 to 7 wt%. The bovine enamel surface was treated with self-etching primer for 30 s. After drying, a stainless steel rod was bonded to the enamel using TBB-initiated 4-META/MMA resin cement. The tensile bond strengths were measured after 1 day of immersion in 37 degrees C water and after thermal cycles between 4 degrees C and 60 degrees C. The resin-enamel interface was observed under field-emission scanning electron microscopy (FE-SEM).


RESULTS
The self-etching primer containing 5 wt% ferric chloride (Phosmer-5Fe) yielded the highest mean bond strength and significantly higher bond strengths than phosphoric acid etching after 1 day of immersion. After 5000 thermal cycles, the bond strength with Phosmer-5Fe was still significantly higher than that with phosphoric acid etching. FE-SEM images revealed tight bonding between the resin and enamel in the specimens of Phosmer-5Fe primer treatment.


CONCLUSIONS
The self-etching primer treatment may be an alternative to phosphoric acid etching for the adhesion of TBB-initiated 4-META/MMA resin cement to enamel.
Hayakawa
Tohru
T
Department of Dental Materials, Research Institute of Oral Science, Nihon University School of Dentistry at Matsudo, Chiba, Japan. hayakawa@mascat.nihon-u.ac.jp
Nemoto
Kimiya
K
D000134:Acid Etching, Dental / Q000379:methods*; D000818:Animals; D001896:Boron Compounds / Q000737:chemistry*; D002417:Cattle; D002712:Chlorides; D001840:Dental Bonding; D003743:Dental Enamel / Q000648:ultrastructure*; D005290:Ferric Compounds / Q000737:chemistry; D007101:Immersion; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D020366:Methylmethacrylate / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009943:Organophosphorus Compounds / Q000737:chemistry; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry*; D013193:Stainless Steel; D013696:Temperature; D013718:Tensile Strength; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry
D001896:Boron Compounds; D002712:Chlorides; D005290:Ferric Compounds; D008689:Methacrylates; D009943:Organophosphorus Compounds; C074231:Phosmer-M adhesion promoting monomer; D010756:Phosphoric Acids; D019279:Resin Cements; C114321:methacryloxyethyl dihydrogen phosphate; D014867:Water; C009523:tri-n-butylborane; D013193:Stainless Steel; D020366:Methylmethacrylate; C005044:hydroxyethyl methacrylate; C034139:4-methacryloxyethyltrimellitic acid anhydride; C024555:ferric chloride