[Effects of exogenous enzymes on the degradation of adhesive-dentin interfaces].
OBJECTIVE
To compare the effects of exogenous enzymes on the degradation of adhesive-dentin interface.


METHODS
Forty molars were sectioned to expose the middle-coronal dentin surface and randomly divided into two adhesive systems: an etch-and-rinse adhesive Adper Single Bond 2 and a self-etching adhesive G-Bond. After composite building up, the specimens were then randomly assigned to four groups(n=5 for each group)as follows: group 1, 24 h of water storage(the control group); group 2, six months of water storage; group 3, twelve weeks storage in artificial saliva containing clostridium histolyticum collagenase; group 4, twelve weeks storage in artificial saliva containing cholesterolesterase. The microtensile bond strengths(MTBS)were then tested. The failure modes and nanoleakage were analyzed.


RESULTS
After aging treatments, the three aging groups showed significantly lower MTBS compared with the control group in both adhesive systems(P<0.05). For etch-and-rinse adhesive Adper Single Bond 2, the MTBS of group 3([19.6±3.5]MPa)was lower than that of group 2([23.4±4.2]MPa)and group 4([24.2±4.2]MPa)(P<0.05). For self-etching adhesive G-Bond, there was no difference on MTBS among different aging groups(P>0.05). SEM observation showed that, compared with the control group, water storage(group 2)and the exogenous enzymes(group 3 and 4)increased the nanoleakage expression(silver deposition)of both adhesive systems. Adhesive failure was the predominant fracture modes in all groups.


CONCLUSIONS
Storage in artificial saliva containing clostridium histolyticum collagenase or cholesterol esterase could be used to accelerate the degradation process of adhesive-dentine interface.
Central Clinic, School of Stomatology, Wuhan University, Wuhan 430022, China.
D L
DL
Deng
The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School of Stomatology, Wuhan University, Wuhan 430079, China.
H Y
HY
Yang
The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School of Stomatology, Wuhan University, Wuhan 430079, China.
J M
JM
Guo
Department of Prosthodontics, School of Stomatology, Wuhan University, Wuhan 430079, China.
C
C
Huang
The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School of Stomatology, Wuhan University, Wuhan 430079, China.
J
J
Gan
The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School of Stomatology, Wuhan University, Wuhan 430079, China.
F F
FF
Song
D000269:Adhesives; D001840:Dental Bonding; D003738:Dental Cements; D003804:Dentin / Q000187:drug effects*; D003781:Denture Retention; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates; D003012:Microbial Collagenase / Q000494:pharmacology*; D011897:Random Allocation; D012464:Saliva, Artificial; D002787:Sterol Esterase / Q000494:pharmacology*; D013718:Tensile Strength / Q000187:drug effects*
D000269:Adhesives; C554641:Adper single bond 2; D003738:Dental Cements; C498353:G-Bond; D008689:Methacrylates; D012464:Saliva, Artificial; D002787:Sterol Esterase; D003012:Microbial Collagenase