In vivo long-term durability of the bond to dentin using two adhesive systems.
OBJECTIVE
The objective of this work was to evaluate the in vivo long-term durability of bond strength and morphological appearance of interfaces between dentin and two adhesive systems.


METHODS
Class V cavities were prepared on the facial surfaces of 6 intact teeth of a monkey, and restored with Unifil Bond/Unifil F and Fuji Bond LC/Clearfil AP-X. One year later, 10 other teeth were restored with the same materials and the monkey was sacrificed after 24 hours. For in vitro examination, 6 more teeth were extracted from the monkey, restored in a similar manner with the two materials, and stored in 37 degrees C water for 1 day. All specimens were subjected to the microtensile bond strength (microTBS) test. The debonded surfaces of specimens were morphologically observed with the FE-SEM.


RESULTS
There were no statistically significant differences among the mean microTBS obtained for Unifil Bond/Unifil F under the three conditions (1 day and 1 year in vivo, and 1 day in vitro), and most specimens showed cohesive failure within resin composite (Unifil F). However, FE-SEM observations showed that resinous material within the hybrid layer made by Unifil Bond seemed to increase in porosity after 1 year. For Fuji Bond LC/Clearfil AP-X, pTBS at 1 day in vitro was significantly higher than that at 1 year in vivo, and bond strengths in vivo tended to decrease over time, although a statistically significant difference was not observed. From FE-SEM observations, most specimens showed cohesive failure within the adhesive (Fuji Bond LC).


CONCLUSIONS
Bond strengths of the two adhesive systems tended to decrease for 1 year in vivo.
Takahashi
Akiko
A
Department of Oral Health Science, Hokkaido University Graduate School of Dental Medicine, Sapporo, Japan. akiko@den.hokudai.ac.jp
Inoue
Satoshi
S
Kawamoto
Chiharu
C
Ominato
Rika
R
Tanaka
Toru
T
Sato
Yasuyo
Y
Pereira
Patricia N R
PN
Sano
Hidehiko
H
D000268:Adhesiveness; D000269:Adhesives / Q000737:chemistry*; D000704:Analysis of Variance; D000818:Animals; D001840:Dental Bonding; D003737:Dental Cavity Preparation / Q000145:classification; D003804:Dentin / Q000648:ultrastructure*; D005899:Glass Ionomer Cements / Q000737:chemistry; D008252:Macaca fascicularis; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D019279:Resin Cements / Q000737:chemistry*; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013696:Temperature; D013718:Tensile Strength; D013997:Time Factors; D014867:Water
D000269:Adhesives; C112828:Clearfil AP-X; D005899:Glass Ionomer Cements; D008689:Methacrylates; D019279:Resin Cements; C407402:Unifil Bond; D014867:Water; C084541:Fuji glass-ionomer lining cement