Elemental distributions and microtensile bond strength of the adhesive interface to normal and caries-affected dentin.
The aim of this study was to evaluate the microtensile bond strength (microTBS) and the elemental contents of the adhesive interface created to normal versus caries-affected dentin. Extracted human molars with coronal carious lesions were used in this study. A self-etching primer/adhesive system (Clearfil Protect Bond) was applied to flat dentin surfaces with normal and caries-affected dentin according to the manufacturer's instructions. After 24 h water storage, the bonded specimens were cross-sectioned and subjected to a microTBS test and electron probe microanalysis for the elemental distributions [calcium (Ca), phosphorus (P), magnesium (Mg), and nitrogen (N)] of the resin-dentin interface after gold sputter-coating. The microTBS to caries-affected dentin was lower than that of normal dentin. The demineralized zone of the caries-affected dentin-resin interface was thicker than that of normal dentin (approximately 3 microm thick in normal dentin; 8 microm thick in caries-affected dentin), and Ca and P in both types of dentin gradually increased from the interface to the underlying dentin. The caries-affected dentin had lost most of its Mg content. The distributions of the minerals, Ca, P, and Mg, at the adhesive interface to caries-affected dentin were different from normal dentin. Moreover, a N peak, which was considered to be the collagen-rich zone resulting from incomplete resin infiltration of exposed collagen, was observed to be thicker within the demineralized zone of caries-affected dentin compared with normal dentin.
Nakajima
Masatoshi
M
Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, Tokyo 113-8549, Japan. nakajima.ope@tmd.ac.jp
Kitasako
Yuichi
Y
Okuda
Mamiko
M
Foxton
Richard M
RM
Tagami
Junji
J
D003731:Dental Caries / Q000628:therapy*; D003738:Dental Cements / Q000737:chemistry / Q000592:standards; D003804:Dentin; D017220:Dentin-Bonding Agents / Q000737:chemistry / Q000592:standards*; D004602:Elements; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D008903:Minerals / Q000032:analysis; D008963:Molar; D013718:Tensile Strength
D003738:Dental Cements; D017220:Dentin-Bonding Agents; D004602:Elements; D008903:Minerals