Objectives: To determine the effects on shear bond strengths of orthodontic brackets to “buccal” and “mesial-distal” surfaces of extracted teeth using different curing lights.
Methods: Eighty human extracted 1st and 2nd bicuspids were selected and embedded in acrylic resin. The specimens were randomly assigned into 8 groups with 10 specimens each. All specimens were etched on enamel using Ultra Etch 35% for 1min and rinsed for 5sec. Eighty-mesh stainless steel premolar orthodontic brackets (Avex MX, Ultradent) were bonded to each specimen using the same adhesive (OpalBond MV, Ultradent) according to the manufacturer's instructions. Specimens were cured using either the buccal (B) or mesial-distal (MD) directions with Halogen (Demetron 501, Kerr), Plasma Arc (Sapphire, DenMat) or LED (Valo, Ultradent) lights. The groups were: 1) Halogen Buccal; 2) Halogen Mesial-Distal; 3) Plasma Arc Buccal; 4) Plasma Arc Mesial-Distal; 5) LED with standard power mode Buccal; 6) LED with standard power mode Mesial-Distal; 7) LED with plasma mode Buccal; and 8) LED with plasma mode Mesial-Distal. Specimens were then incubated in water (37°C) for 24hours. Testing was carried out after using Universal Testing Machine (Instron 5566A, Norwood, MA) with cross head speed 1mm/min. Statistical analysis was accomplished with One-way ANOVA. Tukey-Kramer analysis for pairwise comparison was done to determine if there is a significant difference among groups. Significance for statistical tests was predetermined at p<0.05.
Results:
Group (n=10) | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
Curing Time (Sec) | 20 | 10 | 6 | 3 | 20 | 10 | 10 | 5 |
Mean (MPa+SD) | 12.79±3 | 12.91±1.89 | 12.86±2.34 | 10.49±1.82 | 13.32±3 | 12.89±1.55 | 12.83±2.4 | 11.6±3.2 |
Conclusion: There was no statistically significant difference in shear bond strengths cured from buccal and mesial-distal directions with different types of light-curing. Different curing lights yield no effect on the shear bond strength of non-coated orthodontic brackets.