Durability of resin dentin interfaces: effects of surface moisture and adhesive solvent component.
OBJECTIVE
To analyze the effects of different surface moisture on bond strength (BS) durability of an ethanol/water based, Single Bond (SB); an acetone-based, One-Step (OS); and a water-based, Syntac Single Component (SC) adhesive system to dentin.


METHODS
Forty-five human third molars had their superficial dentin surface exposed flat by abrasion. The adhesives were applied to a delimited area of 52 mm(2) on either air-dried (30 s) or rewetted surfaces (2.5 or 4.0 microl) followed by resin composite build-ups. After storage in water at 37 degrees C (24 h), the teeth were sectioned to obtain bonded sticks with a cross-sectional area of 0.8 mm(2). The sticks, from each tooth, were divided, stored in water at 37 degrees C and tested either immediately or after 6 months (6 M) at 0.5 mm/min. BS was expressed as an index that considers cohesive failures and estimated values of premature debonded specimens.


RESULTS
Three-way ANOVA showed statistically significant effects for moisture degree, storage time and double interactions (p < 0.05). While SB and SC achieved higher BS at 0 and 2.5 microl of water, for OS the BS was higher at 4.0 microl of water. Regardless of the moisture degrees, reductions in BS were observed after 6 M storage for SB and OS (p < 0.05), but not for SC (p > 0.05). No difference in BS between the 24 h and 6 M storage was found when the moisture was set at the extreme conditions. Significant reduction in BS was observed when the moisture was set at 2.5 microl.


CONCLUSIONS
The bond strength of different solvent-based adhesive systems gradually decreases over time, regardless of the variable moisture pattern used for the bonding procedure.
Reis
Alessandra
A
School of Dentistry, University of Oeste de Santa Catarina, Joaçaba, SC, Brazil.
Loguercio
Alessandro D
AD
Carvalho
Ricardo M
RM
Grande
Rosa Helena M
RH
D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003188:Composite Resins; D001840:Dental Bonding; D003806:Dentin Permeability; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004356:Drug Storage; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D017155:Wettability
C103506:Bis-GMA, BPDM, HEMA dental-bonding resin; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D008689:Methacrylates; D019279:Resin Cements; C078484:Syntac dentine adhesive; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate