Evaporating solvents with a warm air-stream: effects on adhesive layer properties and resin-dentin bond strengths.
OBJECTIVE
This study evaluated the effect of a warm or cold air-dry stream for solvent evaporation on the microtensile resin-dentin bond strength (muTBS), nanoleakage pattern (SEM), degree of conversion (DC) and solvent evaporation rates (SE) of an ethanol/water- (Adper Single Bond, [SB] 3MESPE) and an acetone-based (Prime & Bond 2.1, [PB] Dentsply), two-step etch-and-rinse adhesive system.


METHODS
Adhesives were applied on demineralized dentin surfaces. For SE, a warm or cold air-dry stream (10 s) was applied prior to light-activation (10 s). Bonded sticks (0.8mm2) were tested in tension (0.5 mm/min). Two bonded sticks from each tooth were immersed in a 50% (w/v) solution of silver nitrate (24 h), photodeveloped (8 h) and analyzed by SEM. The DC and solvent evaporation rate of the adhesives were evaluated under FTIR and analytical balance, respectively. Data were analyzed by two-way ANOVA and Tukey test (alpha=0.05).


RESULTS
Higher muTBS and lower nanoleakage were observed when the SE step was performed with warm air-dry stream. However, the DC of the adhesives was not altered by the use of a warm air-dry.


CONCLUSIONS
The use of a warm air-dry stream seems to be a clinical tool to improve the bond strength and the quality of the hybrid layer (less nanoleakage infiltration), since it might reduce the number of pores within the adhesive layer.
School of Dentistry, Department of Dentistry, University Luterana do Brasil, Cachoeira do Sul, Rio Grande do Sul, Brazil.
Celso Afonso
CA
Klein-Júnior
Christiana
C
Zander-Grande
Roberto
R
Amaral
Rodrigo
R
Stanislawczuk
Eugênio José
EJ
Garcia
Ricardo
R
Baumhardt-Neto
Márcia Margarete
MM
Meier
Alessandro Dourado
AD
Loguercio
Alessandra
A
Reis
D000096:Acetone / Q000737:chemistry; D000388:Air; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D003080:Cold Temperature; D001840:Dental Bonding; D003763:Dental Leakage / Q000145:classification; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D003890:Desiccation; D000431:Ethanol / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D011109:Polymethacrylic Acids / Q000737:chemistry; D016622:Silver Staining; D012997:Solvents / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013696:Temperature; D013718:Tensile Strength; D014867:Water / Q000737:chemistry
D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; D012997:Solvents; C444444:prime and bond 2.1; C115612:single bond; D014867:Water; D000096:Acetone; D000431:Ethanol; D017438:Bisphenol A-Glycidyl Methacrylate