Efficacy of fluoride associated with nano-hydroxyapatite in reducing enamel demineralization adjacent to orthodontic brackets: in situ study

Abstract

Objective: To assess in situ the effect of fluoride associated with nano-hydroxyapatite for the prevention of demineralization of the enamel adjacent to orthodontic brackets. Material and Methods: Eight volunteers wore palatal devices prepared with 6 bovine enamel blocks (5x5x2 mm) with bonded brackets. The volunteers used the devices in two different moments of 14 days each. During the first 14 days, a product containing fluoride + nano-hydroxyapatite was applied twice (experimental group, GNH, n = 48), and for the other 14 days no prevention product was applied (control group, CG, n = 48). In both groups, along the experiment, the blocks were dripped with 20% sucrose eight times daily. After the experiment, all the specimens were sectioned and examined for lesion depth analysis (µm) under polarized light microscopy, and for enamel longitudinal microhardness (measured under the bracket, at 30 µm and at 130 µm from the margin), at seven different depths (10, 20, 30, 50, 70, 90, and 110 µm). Results: Under polarized light, group GNH presented significantly less demineralization depth ( X ¯= 15.01 µm, SD = 33.65) in relation to CG ( X ¯= 76.43 µm, SD = 83.75). Enamel longitudinal microhardness demonstrated significantly higher microhardness for group GNH when compared to CG. Conclusion: Fluoride + nano-hydroxyapatite can be an alternative preventive procedure for demineralization of the enamel adjacent to orthodontic brackets.

Hydroxyapatite in Oral Care Products—A Review

“…This is supported by a study that investigated the synergistic effects of fluoride and nano-HA on preventing enamel demineralisation around orthodontic brackets [29]. Results revealed significantly less demineralisation depth in the combined nano-HA and fluoride group [29]. Additionally, the combination of nano-HA with fluoride has shown better enamel resistance to erosion in bovine teeth [52].…”

“…However, more studies are needed to determine the optimal nano-HA and NaF mouth rinse conditions for human use [51]. This is supported by a study that investigated the synergistic effects of fluoride and nano-HA on preventing enamel demineralisation around orthodontic brackets [29]. Results revealed significantly less demineralisation depth in the combined nano-HA and fluoride group [29].…”

“…In dentine, nano-HA penetrates into the demineralised collagen matrix acting as a scaffold for remineralisation and provides a good source of calcium locally. Nano-HA has demonstrated significant remineralisation effects over micro-HA due to its smaller particle size being able to remineralise nano-sized enamel defects, and this has become the focus of HA research [29,32,43]. Table 2 provides a summary of the studies conducted on HA and its effects on remineralisation.…”

“…The ideal properties of a dentifrice include minimal abrasive effect, non-irritating, non-toxic, non-staining, protects against caries and biofilm formation, while being costeffective and readily available [21]. Many studies have been conducted to test the efficacy of HA, especially in enamel and dentine remineralisation, biofilm control, reducing dentine sensitivity, and tooth whitening [5,10,11,[22][23][24][25][26][27][28][29][30]. Currently, only a few reviews report on nanomaterial in oral care products or HA in dentistry which includes restorative, preventative, and regenerative applications [5,10,11,31,32].…”

"Regeneration of Permanent Tooth Enamel (Alternative Solution of Nano-hydroxyapatite) after Exposure to Beer (Laboratory Study at the Dental Center, Moscow, Russia)"

“…The surface roughness of the two halves of a tooth is probably not the same. Kislyakov, 2020 in their study by profiling investigate the effect of regular drinks on the microhardness of enamel and the result found that the enamel microhardness decreased after consuming beverages [4,11,12].…”