Shear bond strength comparison of two adhesive systems following thermocycling. A new self-etch primer and a resin-modified glass ionomer.
OBJECTIVE
To compare the effects of a standardized thermocycling protocol on the shear bond strength (SBS) of two adhesive systems: a resin-modified glass ionomer and a composite resin used with a new self-etching primer.


METHODS
Forty human molars were cleaned, mounted, and randomly divided into two groups. In group 1, brackets were bonded to the teeth using Fuji Ortho LC adhesive, and in group 2, the Transbond Plus system was used. The teeth were stored in water at 37 degrees C for 24 hours, thermocycled between 5 and 55 degrees C, and debonded using a universal testing machine. The enamel surface was examined under 10x magnification to determine the amount of residual adhesive remaining on the tooth. Student's t-test was used to compare the SBS and the chi-square test was used to compare the adhesive remnant index (ARI) scores.


RESULTS
The mean SBS for the brackets bonded using the Fuji Ortho LC was 6.4 +/- 4.5 MPa, and the mean SBS for the Transbond Plus system was 6.1 +/- 3.2 MPa. The result of the t-test comparisons (t = 0.207) indicated that there was no significant difference (P = .837) between the two groups. The comparisons of the ARI scores (chi(2) = 0.195) indicated that bracket failure mode was not significantly different (P = .907) between the two adhesives.


CONCLUSIONS
Although SBS and ARI scores were not significantly different for the two adhesives, clinicians need to take into consideration the other properties of the adhesives before using them.
Bishara
Samir E
SE
Orthodontic Department, College of Dentistry, University of Iowa, Iowa City, Iowa 52242, USA. sbishara@msn.com
Ostby
Adam W
AW
Laffoon
John F
JF
Warren
John
J
D000180:Acrylic Resins / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry*; D016009:Chi-Square Distribution; D003738:Dental Cements / Q000737:chemistry*; D017005:Dental Debonding / Q000379:methods*; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength
D000180:Acrylic Resins; D000538:Aluminum Silicates; D003738:Dental Cements; C095451:Fuji Ortho LC; D019279:Resin Cements; C477790:Transbond XT