Interfacial micromorphology and tensile bond strength of dentin bonding systems after NaOCl treatment.
OBJECTIVE
The objective of this study was to test the hypothesis that NaOCl treatment of acid-etched dentin would not lower the tensile bond strength of adhesive resins, but would eliminate the hybrid layer.


METHODS
One hundred twenty teeth and three different bonding agents were used for SEM- and CLSM-visualization of the dentin-composite interface and for bond strength measurements. After etching with phosphoric acid, 75 dentin samples were pretreated with 10% NaOCl. The other 75 samples were etched only with phosphoric acid and were kept as controls. Composite was bonded to the pretreated surfaces with a bonding resin.


RESULTS
NaOCl-treated samples: hybrid layers were not visible, but resin tags and resin penetration through lateral branches of tubules were prominent. Layers of unfilled resin were not apparent for Gluma CPS and Prime & Bond 2.1. Hypochlorite treatment of acid-etched dentin resulted in reduced bond strengths for specimens bonded with Syntac and Gluma CPS, but such treatment increased bond strength for Prime & Bond 2.1 bonded specimens.


CONCLUSIONS
The removal of the collagen layer with NaOCl can enhance or decrease bond strengths, depending on the bonding agent used.
Pioch
T
T
University of Heidelberg, Department of Restorative Dentistry, Im Neuenheimer Feld 400, D-69120 Heidelberg, Germany. thomas_pioch@med.uni-heidelberg.de
Kobaslija
S
S
Schagen
B
B
Götz
H
H
D003188:Composite Resins; D001840:Dental Bonding; D003804:Dentin / Q000187:drug effects* / Q000648:ultrastructure; D003806:Dentin Permeability / Q000187:drug effects*; D017220:Dentin-Bonding Agents; D024022:Fibrillar Collagens / Q000187:drug effects; D005976:Glutaral; D006801:Humans; D008422:Materials Testing; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D008963:Molar; D011109:Polymethacrylic Acids; D019279:Resin Cements; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D018709:Statistics, Nonparametric; D013718:Tensile Strength
D003188:Composite Resins; D017220:Dentin-Bonding Agents; D024022:Fibrillar Collagens; D011109:Polymethacrylic Acids; C425843:Prime and Bond NT; D019279:Resin Cements; C078484:Syntac dentine adhesive; C044372:Gluma; D012973:Sodium Hypochlorite; D005976:Glutaral