Author/Authors :
Salehi, P Department of Orthodontics - School of Dentistry - Shiraz University of Medical Sciences, Shiraz , Malekpour, B Department of Orthodontics - School of Dentistry - Shiraz University of Medical Sciences, Shiraz , Roshan, A Department of Orthodontics - School of Dentistry - Shiraz University of Medical Sciences, Shiraz , Hamedani, Sh School of Dentistry - Shiraz University of Medical Sciences, Shiraz
Abstract :
Statement of problem: Numerous studies report significant changes in tooth
color that occur during orthodontic treatment. The adverse effects of bleaching
procedures during orthodontic treatments have not been studied comprehensively.
Objectives: This study investigated the effects of two methods of dental bleaching
on the degree of microleakage beneath orthodontic brackets.
Materials and Methods: We selected 45 extracted premolar teeth and bonded
them to orthodontic brackets. These teeth were stored in normal saline for 24
hours and thermocycled. We randomly divided the samples into 3 groups of 15
teeth per group. The first group (control) received no bleach treatment; the second
group (office bleaching) was treated with 35% hydrogen peroxide (Whiteness HP
Maxx); and the third group (home bleaching) was treated with 22% carbamide
peroxide (Whiteness Perfect). The apices were sealed with sticky wax, rinsed in
tap water, and air-dried. We applied nail varnish to the entire surface of each tooth,
except for an area approximately 1 mm away from the brackets. The samples
were immersed in basic fuchsine and cleaned after 24 hours. Microleakage was
determined by direct measurement using a stereomicroscope. Kruskal-Wallis
and Dunn post-hoc statistical tests, and SPSS software were used for statistical
analysis. The significance level was set at P≤0.05.
Results: The office bleaching group had significantly more microleakage scores
under the brackets at both the occlusal (P=0.04) and gingival (P =0.040) margins
of the brackets compared to the home bleaching group. The home bleaching group
showed statistically more significant microleakage scores than the control group
in both the gingival (P=0.006) and occlusal (P=0.014) margins of the brackets.
All three groups had statistically more significant microleakage at the gingival
margins of the brackets than the occlusal margins.
Conclusions: Office bleaching caused the most microleakage under the brackets
and home bleaching caused more microleakage than the control group. We
observed more microleakage at the gingival margins of the brackets compared to
the occlusal margins.
