Bioglass Improves Mechanical-properties of White Spot Lesions Surrounding Orthodontic Brackets

Objectives: There are controversies regarding the remineralizing efficiency of agents used to treat white spot lesions surrounding orthodontic brackets. Recently, it was reported the possible formation of a calcium-phosphate rich layer on eroded enamel surface by a 45S5 bioglass paste. This study will examine the effect of the 45S5 bioglass paste on an artificially induced white spot lesion surrounding orthodontic brackets
Methods: Enamel discs were obtained from the buccal surface of 30 extracted human non-carious third molars. Metallic orthodontic brackets were cemented on these teeth using Transbond XT (3M, USA). The surrounding enamel surfaces were coated with 2 layers of acid-resistant nail varnish except for a 2 mm of a treatment window surrounding the orthodontic brackets. All specimens were challenged for 4 days using a buffered demineralization solution pH 4.5. The specimens were divided equally into 4 groups n=10 where the Bioglass paste was applied for 24 hours in (bioglass group), 2% sodium fluoride gel (9000ppmf, BeeBrand, Japan) was applied for 4 minutes, 24 hours in (fluoride 4 minutes group) and (Fluoride 24 hours group) respectively, while the rest of specimens served as (control group). All specimens were embedded, longitudinally cross-sectioned through their treatment window, polished; and the cross-sectional microhardness was measured using a 25-gram load applied for 5 s. The indentations were made at 30, 50, 70, and 100 µm from the outer enamel surface. The cross-sectional Vicker’s hardness numbers (VHN) were calculated. One way ANOVA was used to compare the VHN for all groups p<0.05.
Results: 45S5 bioglass paste application significantly improved the subsurface of the white spot lesion enamel when compared to all other groups (p<0.05).
Conclusions: 45S5 bioglass paste can efficiently remineralize the sub-surface of the white spot lesions associated with orthodontic brackets.