NaOCl degradation of a HEMA-free all-in-one adhesive bonded to enamel and dentin following two air-blowing techniques.
OBJECTIVE
Phase-separation within HEMA-free all-in-one dental adhesives may result in the entrapment of droplets within the adhesive resin. Strongly air-blowing prior to polymerization, can remove most of these droplets. The objective of this study was to evaluate the effect these droplets may have on the resistance of the adhesive-tooth interface to NaOCl degradation.


METHODS
The micro-tensile bond strength (microTBS) to enamel and dentin was determined when a HEMA-free all-in-one adhesive was applied either following a mild or strong air-blowing technique. The bonds were also exposed to an aqueous sodium hypochlorite (NaOCl) solution for 1h, following a recently introduced methodology to mimic in vivo bond degradation.


RESULTS
This study revealed that strong air-blowing of the adhesive only resulted in a significantly higher micro-tensile bond strength (microTBS) to dentin, but not to enamel. Likewise, NaOCl only reduced the microTBS to dentin for both the mild and strong air-blowing technique, but again not the microTBS to enamel. Failure analysis by SEM clearly revealed that strong air-blowing is less effective in droplet removal when the adhesive was applied in small and narrow class-I cavities, as compared to when it was applied to flat surfaces.


CONCLUSIONS
NaOCl did preferentially dissolve the hybrid layer at dentin, and more for the mild than for the strong air-blowing technique. A strong air-blowing procedure resulted in a more NaOCl-resistant hybrid layer, so that it can be concluded that a HEMA-free one-step adhesive definitely benefits from a strong air-blowing technique.
De Munck
Jan
J
Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-facial Surgery, Catholic University of Leuven, Belgium. jan.demunck@med.kuleuven.be
Ermis
R Banu
RB
Koshiro
Kenichi
K
Inoue
Satoshi
S
Ikeda
Takatsumi
T
Sano
Hidehiko
H
Van Landuyt
Kirsten L
KL
Van Meerbeek
Bart
B
D000388:Air; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent / Q000379:methods; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008855:Microscopy, Electron, Scanning; D012973:Sodium Hypochlorite / Q000009:adverse effects*; D012997:Solvents / Q000009:adverse effects*; D013718:Tensile Strength
D017220:Dentin-Bonding Agents; D012997:Solvents; D012973:Sodium Hypochlorite