[Studies on bonding interfaces of two dentin adhesives by scanning electron microscopy].
OBJECTIVE
To purpose of this study was to investigate the microstructure and bonding mechanism of bonding interfaces of two current one-bottle dentin bond systems(Prime & Bond NT, PBNT; Prime one Mirage, P-One).


METHODS
Fifteen extracted, caries-free human molars were prepared according to a modified method used for microtensile bond strength measurement. Each crown was divided into nearly equal halves with a 5 mm deep slot for accepting treatment of the two dentin bond systems, respectively. After 24 h storage in distilled water at 37 degrees C, the bonded teeth were subjected to two treatments: 5 teeth were observed by and tested for microtensile bond strengths without further treatment and 10 teeth were thermocycled(2400 cycles, between 5 degrees C and 55 degrees C) prior to SEM observation and bond strength testing. Hour-glass shaped microspecimens with a thickness of approximately 0.5 mm were cut from each tooth and used for SEM observation and microtensile bond strength measurement.


RESULTS
A typical resin-infiltrated zone (hybrid layer) with a thickness of 3-5 microns and well-formed cone shaped resin tags that penetrated the dentinal tubules were clearly observed at the resin-dentin interfaces in the two bond systems. There were multiple lateral branches of tubular resin tags that interconnected to form a micro-network of resin. No evident differences in SEM images between the two bond systems as well as between thermocycling and without thermocycling in each bond system were found.


CONCLUSIONS
PBNT and P-One provided good resin infiltration, producing a three-dimensional interlocking micro-network of resin tags in the dentin tubules with multiple lateral branches that penetrate the intertubular dentin, which positively influenced the adhesion between dentin and the two bond systems.
Xie
Baosheng
B
Department of Stomatology of Kunming Medical College, Kunming 650031, China.
Dickens
Sabine H
SH
Schumacher
Gary E
GE
Giuseppetti
A A
AA
D001840:Dental Bonding; D003738:Dental Cements / Q000737:chemistry; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008963:Molar / Q000293:injuries / Q000648:ultrastructure; D013718:Tensile Strength
D003738:Dental Cements; D017220:Dentin-Bonding Agents