ABSTRACT
Objectives: To evaluate the effects of fluorosis and bleaching on shear bond strengths
of orthodontic brackets.
Methods: A total of 45 (30 fluorosed and 15 non-fluorosed) non-carious freshly extracted
human permanent premolar teeth which were extracted for orthodontic reasons and without
any caries or visible defects were used in this study. Fluorosed teeth were selected
according to the modified Thylstrup and Fejerskov index (TFI), which is based on the
clinical changes in fluorosed teeth. First group consisted of 15 fluorosed teeth.
Second group of fluorosed teeth were bleached with a 35% hydrogen peroxide office
bleaching agent. Third group served as control. No bleaching procedure was applied.
Orthodontic brackets were bonded with a light cure composite resin and cured with
a halogen light. After bonding, shear bond strengths of the brackets were tested with
Universal testing machine.
Results: The results showed that fluorosis only and bleaching of fluorosed teeth significantly
reduced the bond strengths of the orthodontic brackets (P>.001). Although bleaching
of fluorosed
teeth decreased the values more, no statistically significant difference was found
between fluorosis
group and fluorosis+bleaching group (P<.05).
Conclusions: Fluorosis and bleaching of fluorosed teeth reduce bracket bond strength
to enamel, but the bond strength with these still exceed the minimum 6 to 8 MPa required
to expect adequate clinical performance. (Eur J Dent 2007;1:230-235)
Key words
Fluorosis - Bleaching - Shear bond strength - Hydrogen peroxide
