Effect of smear layer deproteinizing on resin-dentine interface with self-etch adhesive

TY - JOUR

T1 - Effect of smear layer deproteinizing on resin-dentine interface with self-etch adhesive

AU - Thanatvarakorn, Ornnicha

AU - Nakajima, Masatoshi

AU - Prasansuttiporn, Taweesak

AU - Ichinose, Shizuko

AU - Foxton, Richard M.

AU - Tagami, Junji

PY - 2014/3

Y1 - 2014/3

N2 - Objectives: This study aimed to investigate deproteinizing effect of sodium-hypochlorite (NaOCl) and mild acidic hypochlorous-acid (HOCl) pretreatment on smear layer-covered dentine and to evaluate their effects on morphological characteristics of resin-dentine interface with self-etch adhesive. Methods: Human coronal-dentine discs with standardized smear layer were pretreated with 6% NaOCl or 50 ppm HOCl for 15 s or 30 s. Their deproteinizing effects at the treated smear layer-covered dentine surfaces were determined by the measurement of amide: phosphate ratio using ATR-FTIR analysis. In addition, using TEM, micromorphological alterations of hybridized complex and nanoleakage expression were evaluated at the interface of a selfetch adhesive (Clearfil SE Bond) to the pretreated dentine surface with or without subsequent application of a reducing agent (p-Toluenesulfinic acid salt; Accel (R)). Results: Both pretreatments of NaOCl and HOCl significantly reduced the amide: phosphate ratio as compared with the no-pretreated group (p < 0.05), coincident with the elimination of the hybridized smear layer on their bonded interfaces. Nanoleakage within the hybrid layer was found in the no-pretreated and NaOCl-pretreated groups, whereas the subsequent reducing agent application changed the reticular nanoleakage to spotted type. HOCl-pretreated groups showed less nanoleakage expression in a spotted pattern, regardless of reducing agent application. Conclusions: NaOCl and HOCl solutions could remove the organic component on the smear layer-covered dentine, which could eliminate the hybridized smear layer created by selfetch adhesive, leading to the reduction of nanoleakage expression within hybrid layer. Clinical significance: Smear layer deproteinizing could modify dentine surface, giving an appropriate substrate for bonding to self-etch adhesive system.

AB - Objectives: This study aimed to investigate deproteinizing effect of sodium-hypochlorite (NaOCl) and mild acidic hypochlorous-acid (HOCl) pretreatment on smear layer-covered dentine and to evaluate their effects on morphological characteristics of resin-dentine interface with self-etch adhesive. Methods: Human coronal-dentine discs with standardized smear layer were pretreated with 6% NaOCl or 50 ppm HOCl for 15 s or 30 s. Their deproteinizing effects at the treated smear layer-covered dentine surfaces were determined by the measurement of amide: phosphate ratio using ATR-FTIR analysis. In addition, using TEM, micromorphological alterations of hybridized complex and nanoleakage expression were evaluated at the interface of a selfetch adhesive (Clearfil SE Bond) to the pretreated dentine surface with or without subsequent application of a reducing agent (p-Toluenesulfinic acid salt; Accel (R)). Results: Both pretreatments of NaOCl and HOCl significantly reduced the amide: phosphate ratio as compared with the no-pretreated group (p < 0.05), coincident with the elimination of the hybridized smear layer on their bonded interfaces. Nanoleakage within the hybrid layer was found in the no-pretreated and NaOCl-pretreated groups, whereas the subsequent reducing agent application changed the reticular nanoleakage to spotted type. HOCl-pretreated groups showed less nanoleakage expression in a spotted pattern, regardless of reducing agent application. Conclusions: NaOCl and HOCl solutions could remove the organic component on the smear layer-covered dentine, which could eliminate the hybridized smear layer created by selfetch adhesive, leading to the reduction of nanoleakage expression within hybrid layer. Clinical significance: Smear layer deproteinizing could modify dentine surface, giving an appropriate substrate for bonding to self-etch adhesive system.

KW - Sodium-hypochlorite

KW - Hypochlorous-acid

KW - Smear layer deproteinizing

KW - Attenuated total reflection Fourier transform infrared

KW - Hybridized smear layer

KW - Nanoleakage

KW - SODIUM-HYPOCHLORITE

KW - BOND STRENGTH

KW - NANOLEAKAGE

KW - PRETREATMENT

KW - WATER

KW - ACID

KW - DURABILITY

KW - RINSE

U2 - 10.1016/j.jdent.2013.11.026

DO - 10.1016/j.jdent.2013.11.026

M3 - Article

SN - 0300-5712

VL - 42

SP - 298

EP - 304

JO - Journal of Dentistry

JF - Journal of Dentistry

IS - 3

ER -