Are one-step adhesives easier to use and better performing? Multifactorial assessment of contemporary one-step self-etching adhesives.
OBJECTIVE
The objective of this study was to examine whether one-step self-etching adhesives (1-SEAs) really have an advantage over multistep systems.


METHODS
Nine one-step self-etching adhesives (Absolute, Adper Prompt L-Pop, Clearfil S3 Bond, G-Bond, Hybrid Bond, iBond, One-up Bond F Plus, Optibond All-in-one and Xeno III) were included in this study. One two-step self-etching adhesive (Clearfil SE Bond) and one three-step etch-and-rinse adhesive (Optibond FL) served as controls. Their microtensile bond strength to bur-cut enamel and dentin was determined using a standardized protocol and the respective adhesive/dentin interface of these adhesives was characterized by transmission electron microscopy. Statistical analysis was performed with the Kruskal-Wallis nonparametric test.


RESULTS
Regarding bond strength, the control adhesives tended to perform superior to the one-step adhesives. However, a significant difference between the control adhesives and some one-step adhesives could not always be demonstrated, partly due to the statistical setup of this study. Interface analysis by electron microscopy showed wide variation among the one-step adhesives, depending on their composition and their acidity. 1-SEAs also exhibited two different kinds of droplets, depending on their hydrophilicity. Hydrophobic HEMA-free 1-SEAs such as G-Bond were prone to phase separation, while especially HEMA-containing hydrophilic 1-SEAs, such as Clearfil S3 Bond and Xeno III were predisposed to forming osmosis-induced droplets. Hybrid bond, Absolute, and iBond featured both phase separation as well as osmosis. Optibond All-in-one exhibited a clustering reaction of the filler particles upon solvent evaporation. All adhesives including the control adhesives showed signs of nanoleakage, indicating that all adhesives are to some extent permeable to water. A definitive conclusion with regard to quantitative assessment of nanoleakage was much hindered by inconsistencies in the silver deposition. The application procedure of some 1-SEAs sometimes proved as elaborate and time consuming as those of the two-step adhesive Clearfil SE Bond.


CONCLUSIONS
Considering bond strength and application procedure, 1-SEAs are not always a better alternative to multistep adhesives.
Van Landuyt
Kirsten L
KL
Fund for Scientific Research Flanders, Leuven BIOMAT Research Cluster, Department of Conservative Dentistry, School of Dentistry, Oral Pathology and Maxillo-Facial Surgery, Catholic University of Leuven, Leuven, Belgium.
Mine
Atsushi
A
De Munck
Jan
J
Jaecques
Siegfried
S
Peumans
Marleen
M
Lambrechts
Paul
P
Van Meerbeek
Bart
B
D000134:Acid Etching, Dental / Q000379:methods; D001840:Dental Bonding / Q000379:methods*; D003743:Dental Enamel; D003763:Dental Leakage; D003799:Dental Stress Analysis; D003804:Dentin; D006801:Humans; D008422:Materials Testing / Q000379:methods; D046529:Microscopy, Electron, Transmission; D008964:Molar, Third; D019279:Resin Cements / Q000737:chemistry; D013718:Tensile Strength; D013997:Time Factors; D017155:Wettability
D019279:Resin Cements