Effect of water storage on ultimate tensile strength and mass changes of universal adhesives.
BACKGROUND
The aim of the present study was to evaluate the influence of water storage on micro tensile strength (µTS) and mass changes (MC) of two universal adhesives.


METHODS
10 disk-shaped specimens were prepared for each adhesive; Scotchbond Universal (SCU) All-Bond Universal (ABU) and Adper Single Bond 2 (SB2). At the baseline and after 1 day and 28 days of water storage, their mass were measured and compared to estimate water sorption and solubility. For µTS test, 20 dumbbell shaped specimens were also prepared for each adhesive in two subgroups of 1 day and 28 days water storage.


RESULTS
MC was significantly lower for SCU and ABU than SB2 (P< 0.05) at both time intervals. In all three adhesives, the MC was significantly lower at 28 days compared to that at 1 day (P< 0.05). Similarly, µTS was significantly higher for SCU and ABU than SB2 at both storage intervals (P< 0.05). After 28 days, µTS increased significantly for universal adhesives (P< 0.05).


CONCLUSIONS
MC and µTS of adhesives were both material and time dependent when stored in water; both universal adhesives showed less water sorption and higher values of µTS than the control group.Key words:Absorption, dental adhesives, dentin-bonding agents, solubility, tensile strength.
Graduate Student, Research Institute of Dental Sciences, Dental school, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Nazanin
N
Bahrololumi
Graduate Student, Research Institute of Dental Sciences, Dental school, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Amirreza
A
Beglou
Faculty Member, Department of Restorative Dentistry, Dental School, Shahid Beheshti university of Medical Sciences, Tehran, Iran.
Ahmad
A
Najafi-Abrandabadi
Acting Associate Professor, University of Washington School of Dentistry, 1959 NE Pacific St, Seattle, WA 98195, United States; Adjunct Associate Professor, International Exchange Center, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
Alireza
A
Sadr
Assistant Professor, Department of Restorative Dentistry, Dental School, Shahid Beheshti university of Medical Sciences, Tehran, Iran.
Seyedeh-Mahsa
SM
Sheikh-Al-Eslamian
Full Professor, Preventive Dentistry Research Center, Research Institute of Dental Sciences, Department of Restorative Dentistry, Dental School, Shahid Beheshti university of Medical Sciences, Tehran, Iran.
Amir
A
Ghasemi