Bonding durability of HEMA-free and HEMA-containing one-step adhesives to dentine surrounded by bonded enamel.
OBJECTIVE
To evaluate the bonding durability of HEMA-free and HEMA-containing one-step adhesives to dentine surrounded by bonded enamel after 1-year storage in water.


METHODS
Flat coronal dentine surfaces of extracted human molars were prepared, leaving the surrounding enamel. Two one-step self-etch adhesive systems: HEMA-containing Tri-S Bond (TSB; Kuraray Medical Inc., Tokyo, Japan) and HEMA-free G Bond (GB; GC Co., Tokyo, Japan), were applied to both dentine and the surrounding enamel surfaces according to manufacturers' instructions. Following resin composite crown (Clearfil AP-X, Kuraray Medical Inc., Tokyo, Japan) build-ups, the bonded specimens were stored in 37 degrees C water for 24h (control group), 3 months, 6 months and 1 year. After the designated periods of water storage, the specimens were serially sectioned perpendicular to the adhesive interface into 0.7 mm thick slabs, and then trimmed to form hour-glass configurations with a 1mm2 cross-sectional area. The micro-tensile bond strength (muTBS) test was carried out at a crosshead speed of 1.0mm/min. The muTBS data were statistically analyzed using two-way ANOVA, t test, and Tukey's HSD post hoc multiple comparison tests (alpha=0.05).


RESULTS
After 1 year water of storage, the bond strength of TSB to dentine was significantly lower compared with the 1-day, 3-month and 6-month groups (p<0.05). On the other hand, the muTBS of GB decreased over time, but there was no significant difference between the experimental periods (p>0.05).


CONCLUSIONS
Bonded enamel margins may not maintain the integrity of the resin-dentine interface created by HEMA-free and HEMA-containing one-step adhesives.
Torkabadi
Shiva
S
Cariology and Operative Dentistry, Department of Restorative Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. shivatorkabadi@yahoo.com
Nakajima
Masatoshi
M
Ikeda
Masaomi
M
Foxton
Richard M
RM
Tagami
Junji
J
D000704:Analysis of Variance; D001840:Dental Bonding / Q000379:methods*; D003804:Dentin / Q000187:drug effects; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D006801:Humans; D008689:Methacrylates / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013718:Tensile Strength / Q000187:drug effects
D017220:Dentin-Bonding Agents; D008689:Methacrylates; C005044:hydroxyethyl methacrylate