Effects of fluoride on proliferation and mineralization in periodontal ligament cells in vitro

Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs—licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.

Gastrodin alleviates bone damage by modulating protein expression and tissue redox state

Fluorosis is a common disease characterized by disruptions in bone metabolism and enamel development. The production of reactive oxygen species is thought to play an important role in fluorosis. Gastrodin (4‐hydroxybenzylalcohol4‐O‐beta‐d‐glucopyranoside) has been reported to have antioxidative activity, and so here we examined whether gastrodin has protective effects against oxidative stress and bone tissue toxicity in rats with fluorosis. Wistar rats were given different doses of gastrodin 1 month after fluoride administration, and samples of blood, bone and teeth were collected after 2, 3 and 4 months; glutathione peroxidase glu, CAT and SOD levels in the fluorosis group were lower than those in the control group. Gastrodin treatment in rats ameliorated oxidative stress and fluoride accumulation that were induced by fluoride; treatment with 400 mg·kg⁻¹ gastrodin protected trabecular bone structure and reduced femur and alveolar bone injury in rats with fluorosis. Enhanced expression of cysteinyl aspartate‐specific proteinase (caspase) 3, caspase‐9 and Bax and decreased expression of Bcl‐2 induced by fluoride were also reversed by gastrodin. In summary, the present data suggest that gastrodin, and in particular a dose of 400 mg·kg⁻¹, can improve the antioxidative capacity of rats, reduce concentration of fluoride in tissues, alleviate bone damage and modulate expression of Bcl‐2, Bax, caspase‐3 and caspase‐9.

Effect of in vitro sodium fluoride treatment on CAT, SOD and Nrf mRNA expression and immunolocalisation in chicken (Gallus domesticus) embryonic gonads

In this study, we examined the effect of sodium fluoride (NaF) on oxidative stress in chicken embryonic gonads. Following exposure to varying concentrations of NaF for 6 h, mRNA expression and immunolocalisation of catalase (CAT), sodium dismutase (SOD1 and SOD2) and nuclear respiratory factors (Nrf1 and Nrf) were analysed in the gonads. In the ovary, a dose-dependent increase in mRNA expression of CAT, Nrf1 and Nrf2 following NaF exposure was found, while the intensity of immunolocalised CAT, SOD2 and Nrf1 was higher in NaF-treated groups. In the testis, no effect of NaF on CAT, SOD1 and Nrf1 mRNA levels was observed; however, NaF (3.5-14.2 mM) elevated Nrf2 mRNA expression. NaF, at a dose of 7.1 mM, increased the immunoreactivity of Nrf1 and SOD2. Further experiments evaluated the ovary and testes when incubated with NaF (7.1 mM), vitamin C (Vitamin C, 4 mM) or NaF + Vitamin C. mRNA expression of all four examined genes in the whole ovary and immunoreactivity of Nrf1 and CAT in the ovarian medulla increased in each experimental group. Similar effects were observed in the testis, where mRNA expression, as well as CAT and Nrf2 immunoreactivity, increased in Vitamin C and NaF + Vitamin C-treated groups. In summary, NaF exposure generated oxidative stress which is manifested by increased expression of free radical scavenging enzymes in chicken embryonic gonads. High doses of Vitamin C did not reverse this effect.

Sodium fluoride regulates the osteo/odontogenic differentiation of stem cells from apical papilla by modulating autophagy

Fluoride (sodium fluoride) is thought to be essential in the development of tooth, and research shows that fluoride can modulate the differentiation of dental stem cells. However, the effects of fluoride on the committed differentiation of stem cells from apical papilla (SCAPs) and the underlying mechanisms remain unclear. Here, SCAPs were isolated from healthy extracted human third molars with immature roots and then were cultured with NaF conditioned media. Cell Counting Kit-8, EdU staining, and flow cytometry were performed to detected the proliferation activity. Alkaline phosphatase (ALP) activity, Alizarin Red staining, Western blot assay, and real-time reverse-transcription polymerase chain reaction were applied to assess the osteo/odontogenic differentiation NaF-treated SCAPs. Western blot assay and transmission electron microscope were used to evaluate the autophagy involved in the differentiation of SCAPs. ALP activity, ALP protein, and messenger RNA (mRNA) expression showed that 0.5 mM was the optimal concentration for the induction of SCAPs by NaF. 0.5 mM NaF-treated SCAPs induced more mineralized nodules as compared with untreated cells. Moreover, the osteo/odontogenic markers (RUNX2, OSX, DSP, and OCN) in mRNA levels were upregulated while the protein levels of these markers increased considerably in 0.5 mM NaF-treated SCAPs. Furthermore, the autophagy-related proteins (LC3, ATG5, and Beclin1) increased in NaF-treated SCAPs, and the osteo/odontogenic makers significantly decreased while silencing ATG5 to block autophagy. In all, sodium fluoride can regulate the osteo/odontogenic differentiation of SCAPs by modulating autophagy.

Hydrofluoric acid treatment of titanium surfaces enhances the proliferation of human gingival fibroblasts

The attachment of implants relies on bone and soft tissue biocompatibility. The aim of this article is to investigate the effect of fluoride-modified metallic titanium (Ti) surfaces (Ti-F) on proliferation and differentiation of human gingival fibroblasts. Human gingival fibroblast cells were exposed to hydrofluoric acid-modified Ti coins (Ti-F) for 1, 3, 7, 14 and 21 days, and untreated coins were used as controls. A five- to six-fold increase in the proliferation of human gingival fibroblasts on Ti-F compared to Ti surfaces was observed. Enhanced gene expression of interleukin-6 and osteoprotegerin was found at 7 days. Increased levels of sclerostin, interleukin-6 and osteoprotegerin in the media from human gingival fibroblasts cultured on Ti-F coins were found compared to controls. Our results confirm that hydrofluoric acid-modified surface may indirectly enhance the firm attachment of implant surface to junction epithelium, soft tissue epithelium, which would give protection for underlying osseous structures making osseointegration of the dental implant possible.

Effects of nutrition and hygiene education on oral health and growth among toddlers in rural Uganda: follow-up of a cluster-randomised controlled trial

OBJECTIVE

To examine the effect of a nutrition and hygiene education intervention on oral health behaviour and whether early onset of caries was related to child growth in rural Uganda.

METHODS

Follow-up study of a cluster-randomised controlled trial conducted between October 2013 and January 2015. Data were available from 399 mother/child pairs (203 in the intervention and 198 in the control group) of the original trial (78%) when the children were 36 months old. Oral health behaviour was evaluated using questionnaires. Photographs of the maxillary anterior teeth were examined for unmistakably carious lesions, and 115 water samples from the study area were analysed for fluoride concentration.

RESULTS

The frequency of cleaning of the child's teeth at 36 months was about twice as high in the intervention as in the control group (84.3% vs. 46.6%; P = 0.0001). Cavitated carious lesions occurred more frequently in the control than the intervention group (27.8% vs. 18.2%; P = 0.04). Extraction of 'false teeth' (ebiino), a painful and crude traditional operation, was profoundly reduced in the intervention group (8.9% vs. 24.7%; P = 0.001). There was no evidence of association between the occurrence of caries and child growth.

CONCLUSIONS

The education intervention improved oral hygiene practices and reduced the development and progression of caries and extraction of ebiino. Early childhood caries was not clearly associated with child growth.