Many studies on in-vitro orthodontic bond strength fail to report test conditions that could significantly affect their outcomes
INTRODUCTION The aims of this study were to systematic ally review the available literature regarding in-vitro orthodontic shear bond strength testing and to analyze the influence of test conditions on bond strength .
Shear bond strength of orthodontic brackets cemented with a zinc oxide-polyvinyl cement.
The purpose of this study was to compare the shear bond strengths and enamel surface structure after debonding a conventional metal bracket and a polycrystalline ceramic bracket bonded with a bipolar zinc oxide-polyvinyl cement ( F-21 ) or a light-cured resin cement ( Transbond ) .  Forty extracted human premolars were used . The buccal enamel surfaces were used , and the teeth r and omly divided into four groups of 10 teeth each : group 1 : conventional metal bracket ( Unitek ) bonded with Transbond ; group 2 : metal bracket bonded with F-21 ; group 3 : ceramic bracket ( Transcend 2000 ) bonded with Transbond ; and group 4 : ceramic bracket bonded with F-21 . The brackets were bonded to the etched enamel surfaces according to manufacturer 's instructions . All specimens were stored in distilled water for 24 hours and then thermocycled for 300 cycles between 5 degrees C and 55 degrees C. The specimens were mounted in dental stone and placed in the Instron at a crosshead speed of 0.5 mm/min with a knife-edged blade . Immediately after debonding , the enamel surface and bracket-enamel interface were evaluated visually and with a stereomicroscope . Representative sample s were then examined with the scanning electron microscope . The analysis of variance and Student-Newman-Keuls tests were performed . The results in megapascals were Group 1 : 19,6 ( + /- 9,6 ) ; group 2 : 14,3 ( + /- 4,6 ) ; group 3 : 28,8 ( + /- 12,6 ) ; and group 4 : 18,5 ( + /- 7,5 ) . Group 3 was statistically significantly different ( P < 0.008 ) from all other groups . Groups 1 , 2 , and 4 were not significantly different . ( ABSTRACT TRUNCATED AT 250 WORDS
Many studies on in-vitro orthodontic bond strength fail to report test conditions that could significantly affect their outcomes
INTRODUCTION The aims of this study were to systematic ally review the available literature regarding in-vitro orthodontic shear bond strength testing and to analyze the influence of test conditions on bond strength .