Focus on fluorides: update on the use of fluoride for the prevention of dental caries

The effects of an integrated supportive programme on oral health in patients with head and neck cancer undergoing radiotherapy: A randomized controlled trial

OBJECTIVES

This study determines the effect of an integrated 12-month follow-up support programme on the oral health of patients with head and neck cancer (HNC) who received radiotherapy (RT).

METHODS

Participants were randomly assigned to an intervention group (n = 47) or a control group (n = 45). The intervention group received usual care and an integrated supportive programme, which included face-to-face education and telephone coaching. The control group received usual care. After a clinical dental examination, the prevalence of caries, gingival inflammation and plaque were registered. Oral health impact profile (OHIP)-14 and the WHO Oral Health Questionnaire for Adults were used to evaluate oral health in both groups.

RESULTS

A total of 79 participants completed a 12-month follow-up. The intervention group had lower caries increment between baseline and the 12-month follow-up compared with controls, although this was not statistically significant. After 12 months, the intervention group had statistically significant better outcomes in the plaque index (p = 0.038) and the OHIP-14 (p = 0.002) than the control group. No statistically significant differences were found between the two groups concerning gingival index. However, the intervention group reported an overall better state of teeth (p = 0.034) and gums after 12 months (p = 0.042).

CONCLUSIONS

The integrated supportive programme showed positive effects on improving oral health in patients with HNC regarding plaque control, the state of teeth and gums and oral health-related quality of life during the 12-month follow-up.

A systematic review of the association between food insecurity and behaviours related to caries development in adults and children in high-income countries

OBJECTIVES

To synthesize and appraise the evidence regarding the relationship between food insecurity and behaviours associated with dental caries development in adults and children in high-income countries.

METHODS

A systematic review including observational studies assessing the association between food insecurity and selected dietary (free sugar consumption) and non-dietary factors (tooth brushing frequency; use of fluoridated toothpaste; dental visiting; oral hygiene aids; type of toothbrush used; interdental cleaning frequency and mouthwash use) related to dental caries development in adults and children in high-income countries. Studies specifically looking at food insecurity during the COVID-19 pandemic were excluded. Searches were performed in MEDLINE, Embase, Global Health and Scopus from inception to 25 May 2023. Two authors screened the search results, extracted data and appraised the studies independently and in duplicate. Study quality was assessed using the Newcastle-Ottawa Scale (with modifications for cross-sectional studies). Vote counting and harvest plots provided the basis for evidence synthesis.

RESULTS

Searches identified 880 references, which led to the inclusion of 71 studies with a total of 526 860 participants. The majority were cross-sectional studies, conducted in the USA and reported free sugar consumption. Evidence for the association between food insecurity and free sugar intake from 4 cohort studies and 61 cross-sectional studies including 336 585 participants was equivocal, particularly in the sugar-sweetened beverage (SSB) consumption post-hoc subgroup, where 20 out of 46 studies reported higher SSB consumption in food insecure individuals. There was consistent, but limited, evidence for reduced dental visiting in adults experiencing food insecurity compared to food secure adults from 3 cross-sectional studies including 52 173 participants. The relationship between food insecurity and dental visiting in children was less clear (3 cross-sectional studies, 138 102 participants). A single cross-sectional study of 3275 children reported an association between food insecurity and reported failure to toothbrush the previous day.

CONCLUSIONS

This review did not identify clear associations between food insecurity and behaviours commonly implicated in the development of dental caries that would explain why individuals experiencing food insecurity are more likely to have dental caries than those who have food security. There was some evidence of decreased dental visiting in adults experiencing food insecurity. Common methodological weaknesses across the evidence base related to the selection of participants or control of potentially confounding variables. Consequently, the quality of evidence for all outcomes was downgraded to very low. More research is needed to explore access to oral hygiene products and household environments conducive to habitual oral self-care in food insecure populations.

Drinking brick tea containing high fluoride increases the prevalence of osteoarthritis in Tibetan, China

The prevalence of osteoarthritis (OA) in Tibetans is higher than that in Han, while Tibetans have a habit of drinking brick tea with high fluoride. A cross-sectional study was conducted to explore the association between fluoride exposure in drinking brick tea and OA. All subjects were divided into four groups by the quartiles (Q) of tea fluoride (TF) and urine fluoride (UF). ROC was plotted and OR were obtained using logistic regression model. The prevalence of OA in the Q3 and Q4 group of TF were 2.2 and 2.7 times higher than in the Q1 group, and the prevalence of OA in the Q2, Q3 and Q4 group of UF were 3.2, 3.5, and 4.1 times higher than in the Q1 group. ROC analysis showed the cutoff values were 4.523 mg/day (TF) and 1.666 mg/L (UF). In conclusion, excessive fluoride in drinking brick tea could be a risk factor for developing OA.

Development and psychometric analysis: Fluoride varnish parent attitude, belief scale

OBJECTIVE

To develop a scale to determine parents' attitudes and beliefs regarding fluoride varnish.

DESIGN AND METHODS

This study had a cross-sectional design and was conducted between 2019 and 2021. A total of 810 parents were included in the study sample. Exploratory factor analysis (EFA), confirmatory factor analysis (CFA), discriminant validity, and convergent validity methods were used to estimate the scale validity. For reliability, the Cronbach alpha coefficient, item-total correlation coefficients, and test-retest method were used.

RESULTS

As a result of psychometric analysis, the scale was found to have a three-factor structure. The factor loads of the items were between 0.838 and 0.715. The three-factor construct showed a good fit in confirmatory factor analysis (X2 (41): 110.06, p <.001; RMSEA: 0.065; RMSR, 0.02; GFI, 0.95; and NFI, 0.94). Cronbach's α coefficient on the scale was 0.85. The item-total correlation of the scale was found to be between 0.355 and 0.626. The test-retest intra-class correlation coefficient of the scale was 0.72.

CONCLUSIONS

This study suggests that the developed scale is a reliable tool to evaluate the attitudes and beliefs of parents toward fluoride varnish. It is thought that the scale will make a contribution to public health.

Worldwide Variations in Fluoride Content in Beverages for Infants

In situations where breastfeeding is impractical, milk formulas have emerged as the primary choice for infant nutrition. Numerous global studies have scrutinized the fluoride content in these formulas, uncovering fluctuations in fluoride levels directly associated with the method of preparation. This variability poses a potential risk of elevated fluoride concentrations and, consequently, an increased susceptibility to dental fluorosis in infants. The primary objective of this review is to intricately delineate the fluoride content in dairy formulas and emphasize the variability of these values concerning their reconstitution process. The review's findings reveal that, among the 17 studies assessing fluoride levels in infant formula, milk-based formulas exhibit a range of 0.01-0.92 ppm, with only two studies exceeding 1.30 ppm. Conversely, soy-based formulas demonstrate values ranging from 0.13-1.11 ppm. In conclusion, the observed variability in fluoride levels in infant formulas is ascribed to the choice of the water source employed in the preparation process. This underscores the paramount importance of meticulously adhering to recommendations and guidelines provided by healthcare professionals concerning the utilization of these formulas and their meticulous reconstitution.

Managing oral biofilms to avoid enamel demineralization during fixed orthodontic treatment

Enamel demineralization represents the most prevalent complication arising from fixed orthodontic treatment. Its main etiology is the development of cariogenic biofilms formed around orthodontic appliances. Ordinarily, oral biofilms exist in a dynamic equilibrium with the host's defense mechanisms. However, the equilibrium can be disrupted by environmental changes, such as the introduction of a fixed orthodontic appliance, resulting in a shift in the biofilm's microbial composition from non-pathogenic to pathogenic. This alteration leads to an increased prevalence of cariogenic bacteria, notably mutans streptococci, within the biofilm. This article examines the relationships between oral biofilms and orthodontic appliances, with a particular focus on strategies for effectively managing oral biofilms to mitigate enamel demineralization around orthodontic appliances.

A comprehensive review on environmental pollutants and osteoporosis: Insights into molecular pathways

A significant problem that has an impact on community wellbeing is environmental pollution. Environmental pollution due to air, water, or soil pollutants might pose a severe risk to global health, necessitating intense scientific effort. Osteoporosis is a common chronic condition with substantial clinical implications on mortality, morbidity, and quality of life. It is closely linked to bone fractures. Worldwide, osteoporosis affects around 200 million people, and every year, there are almost 9 million fractures. There is evidence that certain environmental factors may increase the risk of osteoporosis in addition to traditional risk factors. It is crucial to understand the molecular mechanisms at play because there is a connection between osteoporosis and exposure to environmental pollutants such as heavy metals, air pollutants, endocrine disruptors, metal ions and trace elements. Hence, in this scoping review, we explore potential explanations for the link between pollutants and bone deterioration through deep insights into molecular pathways. Understanding and recognizing these pollutants as modifiable risk factors for osteoporosis would possibly help to enhance environmental policy thereby aiding in the improvement of bone health and improving patient quality of life.

Relatively low fluoride in drinking water increases risk of knee osteoarthritis (KOA): a population-based cross-sectional study in China

Previous studies indicate that fluoride in drinking water has a toxic effect on cartilage and skeleton, which triggers osteoarthritis (OA) of which the most frequent is knee OA (KOA). A cross-sectional study was conducted to assess the association between fluoride exposure and KOA among 1128 subjects. Water fluoride (WF) and urinary fluoride (UF) were chosen as external exposure (internal exposure) of fluoride. Logistic regression analysis showed that an increased fluoride exposure was a risk factor for KOA (WF: OR = 1.318, 95% CI 1.162-1.495, p < 0.001; UF: OR = 1.210, 95% CI 1.119-1.310, p < 0.001). After adjusting for covariates, the risk of KOA in the 4th quartile (Q) of WF was twice that of the 1st Q (OR = 2.079, 95% CI 1.448-2.986, p < 0.001). The risks of KOA in the 2nd Q, 3rd Q and 4th Q of UF were 1.6, 1.5, and 2.9 times higher than in the 1stQ (OR = 1.597, 95% CI 1.066-2.393, p = 0.023; OR = 1.560, 95% CI 1.043-2.333, p = 0.030; OR = 2.897, 95% CI 1.957-4.288, p < 0.001). The population aged < 60 exposed to the 4th Q of WF (or UF) had a higher risk than the population exposed to the 1st Q of WF (or UF) (ORWF = 1.958, 95% CI 1.249-3.070, p = 0.003; ORUF = 2.923, 95% CI 1.814-4.711, p < 0.001). With increasing UF by Q, the male had a risk of KOA. In conclusion, excessive fluoride dose in drinking water could increase the risk of KOA. Especially, the population with aged < 60, male and obesity more likely to having KOA when they exposed to same higher fluoride.

Tooth brushing with fluoridated toothpaste and associated factors among Chinese adolescents: a nationwide cross-sectional study

BACKGROUND

Tooth brushing with fluoridated toothpaste has become the most important way to provide the anti-caries effect of fluoride around the world. China has promoted the use of fluoridated toothpaste since 1989. However, there are few studies on the national profile of use of fluoridated toothpaste and related factors in Chinese adolescents. We carried out this study to investigate oral hygiene behaviours, especially the status of tooth brushing with fluoridated toothpaste and its correlates among adolescents, based on data from the latest Nation Oral Health Survey in mainland China.

METHODS

This cross-sectional study recruited 118,601 participants aged 12-15 years using multistage stratified sampling. Questionnaires were completed by students at school. Data employed in analyses were extracted from the questionnaire, including information on tooth brushing, fluoridated toothpaste, dental floss, sociodemographic factors, fluoride knowledge and attitude towards regular dental check-ups. A binary logistic regression was performed to compute the odds ratios (OR). Tooth brushing twice daily with fluoridated toothpaste was the dependent variable. Sociodemographic factors, fluoride knowledge, attitude towards regular dental check-ups, dental visit experience and perceived oral health were the independent variables. P < 0.05 was considered statistically significant.

RESULTS

A total of 32.6% of participants brushed their teeth twice daily, 7.4% used fluoridated toothpaste, and 3.9% cleaned their teeth twice daily with fluoridated toothpaste. The logistic regression showed the probability of twice-a-day tooth brushing with fluoridated toothpaste was higher among these groups: females (OR: 1.141; 95%CI: 1.072-1.214), 15-year-olds (OR: 1.786; 95%CI: 1.634-1.952), from urban areas (OR: 1.389; 95%CI: 1.288-1.497), without siblings (OR: 1.351; 95%CI: 1.259-1.450), with an educated father (OR: 1. 605; 95%CI: 1.442-1.788) and mother (OR: 1.706; 95%CI: 1.530-1.903), having dental visit experiences (OR: 1.702; 95%CI: 1.589-1.823), rating one's oral health as good (OR: 2.341; 95%CI: 2.083-2.631), having fluoride knowledge (OR: 4.345; 95%CI: 4.034-4.678) and having a positive attitude towards regular dental check-ups (OR: 1.589; 95%CI: 1.460-1.729).

CONCLUSIONS

The oral hygiene behaviours of Chinese adolescents were undesirable. Twice daily tooth brushing with fluoridated toothpaste was significantly associated with sociodemographic factors, fluoride knowledge, and attitudes towards regular dental check-ups.

Fluoride Varnish in Dentistry: A Bibliometric Analysis of the 100 Most-Cited Papers

A highly cited paper is a milestone and might impact research and clinical practice. The present study analyzed the 100 most-cited papers on fluoride varnishes in dentistry. A search was performed on July 20, 2022, on the Web of Science Core Collection. Two independent researchers extracted the following data: number and citation density; year and journal of publication; study design; main topic; authors; institutions; keywords; countries and continents. Scopus and Google Scholar were consulted to compare the number of citations. Bibliometric networks were generated in the VOSviewer. The number of citations ranged from 36 to 351, and thirteen papers were cited more than 100 times. The papers were published between 1977 and 2018, most of which were published after 2008 (48%). The most prevalent journal was Caries Research (17%). Intervention studies were the most common design (41%). The most discussed topics were dental caries prevention (48%) and dental remineralization (31%). Europe was the continent with the highest number of publications (46%), mainly from Sweden (14%), and Umea University had the most substantial number of studies (8%). Petersson L.G. was the author with more papers in the top 100 (6%). The most used keywords were "dental caries" (34%) and "fluoride varnish" (31%). It can be concluded that the top 100 cited papers on fluoride varnish primarily originated from Europe, with the majority consisting of intervention studies focusing on the utilization of fluoride varnish for the prevention of dental caries.

Effects of topical fluoride treatment on the bond strength of pit and fissure sealants: A systematic review

Background

This systematic review aimed to evaluate the available scientific evidence concerning the effects of topical fluoride treatment on the bond strength of pit and fissure sealants. Prevention of dental caries is one of the crucial issues in pediatric dentistry. Pit and fissure sealant and fluoride therapies are two caries prevention procedures that may be performed in one session. However, fluoride therapy may affect the bond strength of pit and fissure sealants.

Methods

An electronic search for in vitro studies published in English and Persian on topical fluoride therapy and the bond strength of pit and fissure sealants was performed via PubMed/ Medline, Web of Science, Google Scholar, Embase, and Scopus databases until May 2022. The articles were independently reviewed for quality by two reviewers. Textual data were analyzed manually, and the bond strength of sealants placed after fluoride application was compared with control groups.

Results

A total of 8482 articles were initially identified and reviewed by two independent reviewers, and 13 were selected for full-text evaluation. Finally, six articles were included in the systematic review. A total of 250 teeth were studied, 148 of which were in the case group (fluoride group) and 102 in the control group. Tensile and shear bond strengths were compared between groups in the studies.

Conclusion

In the studies in which the tooth surfaces were washed after applying fluoride, there was no change in the fissure sealant bond strength. However, in studies in which fluoride was not washed, the bond strength decreased significantly, independent of the fluoride type.

Caries Experience in Preschoolers in Three Ecuadorian Communities

Dental caries in the preschool population presents a significant challenge in the field of global public health, including Ecuador. Early detection of this disease is crucial for developing effective strategies for prevention and promotion of oral health, which can have a substantial impact on the quality of life of preschool-aged children. This study evaluated 600 children aged 3 to 5 years attending preschool education centers using the ICDAS II diagnostic criteria. The Student's t-test was used to analyze differences between the means of two independent groups. Additionally, an analysis of variance (ANOVA) was conducted to assess differences between the means of three or more groups. The prevalence of caries was 87%, with a dft index of 3.85 in the three provinces studied. A high treatment need was observed in 84.17% of the population. No significant differences in the DFT index were found based on gender, although both groups exhibited elevated values. No significant differences were observed in relation to province and environment. The second molar was the most affected tooth, with a caries prevalence of 58.8%. Despite the lack of significant differences among the evaluated variables, a high prevalence and experience of dental caries were found in the studied population.

Methods of Primary Clinical Prevention of Dental Caries in the Adult Patient: An Integrative Review

AIM

Preventive approaches to oral health diseases, mainly dental caries, require individual and collective policies. Thus, this review was conducted to identify the primary prevention methods of dental caries in adults to improve oral health at the clinical and community levels.

METHODS

This review followed the PICO strategy with the research question: "What are the methods of primary prevention of dental caries, in adults, for improving and maintaining oral health integrating clinical and community-based strategies?" Electronic screening was carried out by two independent reviewers in five databases (MedLine/PubMed, SciELO, Web of Science, Cochrane Library, and LILACS) to find relevant publications between 2015-2022. We applied eligibility criteria for selection of the articles. The following MeSH terms were used: "Primary Prevention"; "Adult"; "Oral Health"; "Dental Caries"; "Fluorides, Topical"; "Fluoride Varnishes"; "Pit and Fissure Sealants"; "Preventive Dentistry". Although the term "Prevention strategy" is not a MeSH descriptor, several correlated terms appeared and were used in the search engines: "Preventative Care", "Disease Prevention, Primary", and "Prevention, Primary". The tool provided by the JBI organization (Joanna Briggs Institute) was used to assess the quality of the included studies.

RESULTS

Nine studies were included. Overall, it was found that the main primary prevention methods applied in dentistry in adults are the application of pit and fissure sealants, topical application of fluoride performed in the dental clinic, use of fluoridated toothpaste, mouthwash with chlorhexidine at home, use of xylitol, the recommendation for regular appointments with the dentist, and the need to inform patients about the saliva buffer capacity and adoption of a non-cariogenic diet. For that purpose, preventive policies should be taken to prevent dental caries. These include three major challenges: providing the adult population with more knowledge regarding their oral health, empowering patients through adopting healthy lifestyles, and developing new preventive strategies and awareness campaigns aimed at the adult population to promote proper oral health habits.

CONCLUSIONS

A small number of studies were found whose participants were adult patients. There was some consistency regarding primary prevention methods in our studies. However, good quality randomized control studies are still required to define the best intervention strategies for adult caries prevention.

Oral health status of students with visual or hearing impairments in Northeast China

BACKGROUND

Visual or hearing impairments in students seriously affect their quality of life. The aim of this study was to identify oral hygiene status and its influencing factors on visual or hearing impairments in students in Northeast China.

METHODS

This study was conducted in May 2022. A total of 118 visually impaired students and 56 hearing impaired students from Northeast China were included in this study via census. Oral examinations and questionnaire-based surveys of students and their teachers were conducted. The oral examinations included caries experience, prevalence of gingival bleeding and dental calculus. The questionnaires included three parts: Social demographics (residence, sex and race) and parents' educational level; Oral hygiene habits and medical treatment behaviors; Knowledge and attitudes towards oral health care. This questionnaire was selected from the Fourth China National Oral Health Survey and the reliability and validity of the questionnaire were previously tested. T tests, one-way ANOVA, χ² tests and multivariate logistic analyses were conducted to evaluate the differences and dependent variables of dental caries.

RESULTS

The prevalence of dental caries in visually impaired and hearing impaired students were 66.10% and 66.07%. The mean number of DMFT, prevalence of gingival bleeding and dental calculus in visually impaired students were 2.71 ± 3.06, 52.08% and 59.38%, respectively. The mean number of DMFT, prevalence of gingival bleeding and dental calculus in hearing impaired students were 2.57 ± 2.83, 17.86% and 42.86%, respectively. The results of the multivariate logistic analysis showed that fluoride use and parents' educational background had an impact on the caries experience of visually impaired students. The daily toothbrushing frequency and parents' educational background had an impact on the caries experience of hearing impaired students.

CONCLUSIONS

The oral health situation of students with visual or hearing impairments remains severe. It is still necessary to promote oral and general health in this population.

Enhanced effect of a novel bioactive glass-ceramic for dental application

OBJECTIVES

Dental caries is the most common chronic disease in humans, caused by the acid produced by the microflora in the mouth that dissolves the enamel minerals. Bioactive glass (BAG) has been used in various clinical applications due to its unique bioactive properties, such as bone graft substitutes and dental restorative composites. In this study, we introduce a novel bioactive glass-ceramic (NBGC) prepared through a sol-gel process under a water-free condition.

MATERIALS AND METHODS

The anti-demineralization and remineralization effects of NBGC were evaluated by comparing the measurements of bovine enamel surface morphology, surface roughness, surface micro-hardness, enamel elements, and mineral content before and after related treatments with a commercial BAG. The antibacterial effect was characterized by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC).

RESULTS

Results showed that NBGC had greater acid resistance and remineralization potential compared to commercial BAG. The fast formation of a hydroxy carbonate apatite (HCA) layer suggests efficient bioactivity.

CLINICAL RELEVANCE

In addition to its antibacterial properties, NBGC shows promise as an ingredient in oral care products that can prevent demineralization and restore enamel.

Knowledge and Practices Regarding Oral Hygiene, Cariogenic Diet Intake, and Dental Check-Ups Among Registered Nurses in Nigeria: A Pilot Study

Objectives To investigate the knowledge and practices of registered nurses in Nigeria concerning oral hygiene, cariogenic diets, and dental check-ups through a pilot study.

Methods This study was an online survey of 129 registered nurses in Nigeria. Data were collected via the WhatsApp social media using an electronic questionnaire (Google form). Data analysis was done using the SPSS version 26 software (IBM Corp, New York, USA).

Results The response and completeness rates of this pilot study were 41.7% (129/311) and 96.9% 9125/129), respectively. The majority (62.2%) of the respondents were females. The majority (89.1%) had average/above average score on basic oral health knowledge; however, there was no significant relationship between their level of basic oral health knowledge and their sociodemographic characteristics (p > 0.05). The majority (66.7%) of the respondents brushed twice daily, 86.8% used a fluoridated toothpaste, and 60.5% changed their toothbrush every 3 months. Furthermore, more than half (55.8%) consumed sugary snack/drink on daily basis, while 55.0% rinsed their mouth with water immediately after taking sugary snack, and only 55.8% did floss their teeth. Among those who flossed their teeth, only 37.5% did it once daily. It is also striking that 26.4% of the respondents had never visited a dentist for a dental check-up.

Conclusion Study findings showed a high level of basic oral health knowledge and a lower level of appropriate oral self-care practices among nurses in Nigeria. However, there is a need for a nationally representative study of nurses in Nigeria to further establish these findings.

Distribution of Dental Fluorosis in the Southern Zone of Ecuador: An Epidemiological Study

In recent decades, the increase in fluoride exposure has raised the numbers of dental fluorosis in fluoridated and non-fluoridated communities In Ecuador, but the last national epidemiological study on DF was conducted more than a decade ago. The objective of this cross-sectional descriptive study was to determine the prevalence, distribution and severity of dental fluorosis (DF) using the Dean index in 1606 schoolchildren aged 6 to 12 years from urban and rural environments in provinces that make up the Southern Region of Ecuador. Participants met the inclusion criteria which were age, locality, informed consent document and no legal impediment. The results are presented using percentage frequency measures and chi-square associations. The prevalence of dental fluorosis was 50.1% in the areas of Azuay, Cañar and Morona Santiago, with no significant differences (x2 = 5.83, p = 0.054). The types of DF found most frequently were very mild and mild in all provinces; a moderate degree was more prevalent in Cañar (17%). There was no significant association (p > 0.05) between sex and the presence of dental fluorosis and, with respect to severity, the most frequent degree was moderate at the age of 12 years. The prevalence of dental fluorosis in the area evaluated is high, especially in the light and very light degrees, with a tendency toward moderate levels. It is necessary to carry out studies on the factors that are predisposing to the development of this pathology in the population studied. This research is an update regarding this pathology in Ecuador, so it is concluded that it is necessary to continue developing studies based on the findings obtained, thus contributing to the public health of the country.

Re-evaluating fluoride intake from food and drinking water: Effect of boiling and fluoride adsorption on food

Although drinking water is the main source of fluoride intake, recent studies reported that fluoride intake from foods could also be high, depending on cooking methods. In this study, we quantified the fluoride accumulation in foods soaked or boiled in fluoride-containing water and assessed the fluoride intake in different age groups from food and drinking water. We observed that, in the case of rice soaked in fluoride-containing water, more fluoride was accumulated in the rice than previously estimated. Fluoride interferes with the iodine staining process of rice, indicating fluoride adsorption. Fluoride accumulation in rice and vegetables increased when the soaking temperature was raised to 100 °C due to the gelatinization of rice grains and softening of vegetables. Ingesting foods boiled in fluoride-containing water increased the fluoride intake per body weight of infants more significantly than that in children and adults due to their low body weight. These results indicate that soaking and boiling foods in fluoride-containing water significantly increases fluoride intake compared to previous estimations. Therefore, it is necessary to re-evaluate the fluoride intake from food and drinking water considering the methods used for cooking food in each country and region.

Red Marine Algae Lithothamnion calcareum Supports Dental Enamel Mineralization

The current management of oral conditions such as dental caries and erosion mostly relies on fluoride-based formulations. Herein, we proposed the use of the remaining skeleton of Lithothamnion calcareum (LC) as an alternative to fluorides. LC is a red macroalgae of the Corallinales order, occurring in the northeast coast of Brazil, whose unique feature is the abundant presence of calcium carbonates in its cell walls. Two experimental approaches tested the general hypothesis that LC could mediate enamel de-remineralization dynamics as efficiently as fluorides. Firstly, the effect of LC on enamel de-mineralization was determined in vitro by microhardness and gravimetric measurements to test the hypothesis that LC could either prevent calcium/phosphate release from intact enamel or facilitate calcium/phosphate reprecipitation on an artificially demineralized enamel surface. Subsequently, an in situ/ex vivo co-twin control study measured the effect of LC on the remineralization of chemical-demineralized enamel using microhardness and quantitative light-induced fluorescence. With this second experiment, we wanted to test whether outcomes obtained in experiment 1 would be confirmed by an in situ/ex vivo co-twin control model. Both experiments showed that LC exhibited equivalent or superior ability to modulate enamel de-remineralization when compared to fluoride solution. LC should be explored as an alternative to manage oral conditions involving the enamel demineralization.

The Safety of Fluoride Compounds and Their Effect on the Human Body-A Narrative Review

Fluoride is one of the elements commonly present in the human environment. Due to its characteristics, it is very widely used in medicine, dentistry, industry or agriculture. On the other hand, its universality possesses a real threat to the human body in the form of acute and chronic poisoning. The aim of this paper is to characterize the properties of fluoride and its effects on the human body, as well as the sources of its occurrence. Particular emphasis is placed on the safety of its use and optimal dosage intake, which prevents accumulation and reduces its potential side effects. The positive effect of proper fluoride supply is widely described. In order to avoid overdose, it is best to consult a specialist to properly select the dosage.

Salivary fluoride bioavailability after use of high-fluoride dentifrices with different compositions: A short-term randomized clinical trial

OBJECTIVE

The objective of the study was to evaluate the kinetics of salivary F bioavailability after the use of high-fluoride dentifrices with different compositions and their amount of total soluble fluoride (TSF).

METHODS

A short-term clinical randomized trial was performed in which 15 adult participants were randomly allocated into three groups: 5000 ppm F-dentifrice, 5000 ppm F-dentifrice + TCP (tri-calcium phosphate) and 1450 ppm F-dentifrice. Unstimulated saliva was collected at different times: baseline (before toothbrushing), immediately after brushing/water rinsing and at 5, 15 and 30 min and 1, 2, 4, 8 and 12 h after brushing. The TSF in dentifrices and saliva samples was analysed using an ion-specific electrode. For statistical analysis, the paired t-test and Kruskal-Wallis were used with Dunn's post-test with a 95% confidence interval.

RESULTS

There was no significant difference between the declared TSF and that found in 5000 ppm F-dentifrice and 1450 ppm F-dentifrice (p ≥ 0.13); however, in the 5000 ppm F-dentifrice + TCP, approximately 500 ppm less TSF was observed (p = 0.0024). The area under the curve (AUC, μg F/ml min-1 ) of both high-fluoride dentifrices (321.7 ± 84.0 and 223.6 ± 55.1 for the one without and with TCP, respectively) was higher than the conventional one (89.97 ± 15.6) attesting a higher F-bioavailability (p = 0.04). Furthermore, they were able to provide F-salivary levels higher than the baseline for up to 2 h, while this time was 1 h for the 1450 ppm F-dentifrice (p ≤ 0.003).

CONCLUSION

Both high-fluoride dentifrices similarly increased the salivary-F bioavailability in comparison with 1450 ppm F-dentifrice, despite the lower TSF presented by the dentifrice containing TCP.

Maintaining and Improving the Oral Health of Young Children

Oral health is an integral part of the overall health of children. Dental caries is a common and chronic disease process with significant short- and long-term consequences. The prevalence of dental caries remains greater than 40% among children 2 to 19 years of age. Although dental visits have increased in all age, race, and geographic categories in the United States, disparities continue to exist, and a significant portion of children have difficulty accessing dental care. As health care professionals responsible for the overall health of children, pediatricians frequently confront morbidity associated with dental caries. Because the youngest children visit the pediatrician more often than they visit the dentist, it is important that pediatricians be knowledgeable about the disease process of dental caries, prevention of disease, interventions to maintain and restore health, and the social determinants of children's oral health.

Fluoride Exposure from Ready-To-Drink Coffee Consumption

Fluoride is present in various foods ingested daily. It has been demonstrated that the intake of high concentrations of fluoride, both in adults and children, can cause pathologies, among which dental fluorosis, osteoporosis and damage to the central nervous system stand out. The objective of this study was to determine the fluoride concentrations in 60 samples of ready-to-drink cold brewed coffee of different brands and types (expresso, cappuccino, macchiato and decaffeinated) by the fluoride ion-selective potentiometric method. A statistical analysis was also performed to discern the existence of differences between these categories. The highest fluoride concentration (1.465 mg/L) was found in espresso coffee followed by Macchiato (1.254 mg/L). Decaffeinated coffee is the one that presented the lowest fluoride concentration with 0.845 mg/L. The risk assessment was conducted considering different consumption scenarios (250, 500 and 750 mL/day). The UL (upper level) established by the EFSA (European Food Safety Authority) at 7 mg/day was used. The consumption of three servings poses no health risk; however, it confers a significant value of fluoride contribution to the diet.

Effects of Photodynamic Therapy on Streptococcus mutans and Enamel Remineralization of Multifunctional TiO2-HAP Composite Nanomaterials

BACKGROUND

As photosensitizer and photocatalyst, titanium dioxide (TiO₂) can produce a photodynamic reaction for antibacterial treatment. This study aims to explore a Titanium dioxide/nano-hydroxyapatite (TiO₂-HAP) composite combined with the dental curing lamp (385-515 nm) in clinical which could inhibit the dental plaque biofilm formed by Streptococcus mutans (S. mutans) and promote the enamel surface remineralization simultaneously.

METHODS

X-ray Diffraction (XRD) and high resolution transmission electron microscope (HRTEM) were used to detect the characterization of TiO₂-HAP composite nanomaterials. Photodynamic properties of TiO₂-HAP were detected by Diffuse reflectance spectrum (DRS) and fluorescence spectroscopy. Bacterial growth was measured by reading the absorbance of bacterial cultures and confocal microscope was used to observe the biofilm removal ability of nanomaterials. The ability of TiO₂-HAP to promote enamel remineralization was measured by Scanning electron microscope (SEM).

RESULTS

The OD 600 of S. mutans was 0.76 in the control group and 0.13 in group of TiO₂-HAP with exposure to light-emitting diode (LED) (150 mW/cm²) for 5 min, suggesting its sustained antibacterial potency and inhibition of the metabolic activity of dental plaque microcosm biofilm. Also, the release of calcium and phosphorus ions in TiO₂-HAP can promote enamel mineralization simultaneously. After 15 days of remineralization, the Ca/P ratio of demineralized enamel surface increased from 1.28 to 1.67, which was similar to that of normal enamel.

CONCLUSIONS

The TiO₂-HAP exhibit a promising anti-bacterial activity and remineralization capacity which can prevent the occurrence of caries to the greatest extent and promote the biomimetic mineralization of dental tissues.

In-depth insights into the disruption of the microbiota-gut-blood barrier of model organism (Bombyx mori) by fluoride

Fluoride is a serious health risk to animals and humans. The microbiota-gut-blood barrier (MGBB) plays an indispensable role in maintaining the systematic homeostasis of host organisms. However, the toxic effects of fluoride on MGBB of organisms have not been extensively investigated. Here, we used the silkworm interspecies model to explore the adverse effects of fluoride on the gut microbiota and intestinal tissue and circulating metabolites of organisms. Results showed that fluoride exposure significantly declined the body weight gain and survival rate of organisms and evidently damaged intestinal epithelial cells. In addition, fluoride altered the composition and abundance of intestinal microbiota, which was accompanied by changing gene expression levels of antimicrobial peptides in intestinal tissue. Shifts in the relative abundance of Enterococcus, Aquabacterium, Aureimonas and Methylobacterium in the gut had significant correlations with the concentrations of certain differential metabolites (e.g., amino acids, nucleotides, and nucleotide derivatives) in the bloodstream. Moreover, most circulating metabolites in related nucleotide metabolism pathways were upregulated, whereas those in the pathways of amino acid metabolism were downregulated. This study deepens our understanding of the disruptive effect of fluoride on the MGBB of host organisms and may provide a new insight into the preventive therapy of fluoride-induced diseases.

Investigation of drug resistance of caries-related streptococci to antimicrobial peptide GH12

Dental caries is associated with caries-related streptococci and antimicrobial agents have been widely used for caries control, but troubled by antibiotic resistance. This study aimed to investigate the intrinsic and acquired resistance of caries-related streptococci to antimicrobial peptide GH12, which was proven promising for caries control, and preliminarily explore the phenotypic changes and whole genome of stable acquired resistant strains. In this study, susceptibility assays and resistance assays were performed, followed by stability assays of resistance, to evaluate the intrinsic resistance and the potential resistance of caries-related streptococci. Then, the phenotypic changes of the stable acquired resistant strain were explored. The whole genome of the resistant strain was sequenced and analyzed by second-generation and third-generation high-throughput sequencing technologies. Streptococcus gordonii and Streptococcus sanguinis were intrinsically resistant to GH12 compared to cariogenic Streptococcus mutans. Acquired GH12 resistance in one S. sanguinis and four S. mutans clinical strains was transient but stable in one S. mutans strain (COCC33-14). However, acquired resistance to daptomycin (DAP) and chlorhexidine in all strains was stable. Furthermore, the COCC33-14 showed cross-resistance to DAP and delayed growth rates and a lower population. However, no drug-resistant gene mutation was detected in this strain, but 6 new and 5 missing genes were found. Among them, annotation of one new gene (gene 1782|COCC33-14R) is related to the integral component of the membrane, and one missing gene rpsN is associated with the metabolism and growth of bacteria. The results indicate that stable resistant mutants of caries-related streptococci could hardly be selected by exposure to consecutive sublethal GH12, but the risk still existed. Resistance in COCC33-14R is mainly related to changes in the cell envelope.

A Scopus-Based Bibliometric Analysis of Global Research Contributions on Milk Fluoridation

Fluoridated-milk schemes have been developed and implemented in many countries to prevent dental caries. This study aimed to evaluate the impact/influence of scientific publications, researchers, and institutions conducting research on milk fluoridation; to explore the international and inter-institutional collaboration and illustrate scientific output trends; and to pinpoint research hotspots in milk fluoridation research. This bibliometric analysis of original research articles on milk fluoridation includes all of the original articles published in peer-reviewed journals systematically extracted from the SCOPUS database. In total, 108 articles were included in this study, with a total of 11,789 citations. A majority (67.6%) of these articles were in the subject area of ‘dentistry’, 22.2% externally funded, 14.8% published in the journal, Caries Research, 7.4% authored/co-authored by Twetman S, 6.5% by authors from Universidad de Chile, and the UK had the highest output (24.1%). The network visualizations showed that those countries with current/past histories of implemented milk fluoridation programs were interconnected on the network visualization map, and they were predominantly the hotspots for original research on milk fluoridation. This study also identified inequalities in research outputs on the topic. With the current enormous global burden of dental caries in children, particularly in low- and middle-income countries, there is an urgent need for greater and more equitable funding of milk fluoridation research globally.

In-vitro evaluation of the anti-cariogenic effect of a hybrid coating associated with encapsulated sodium fluoride and stannous chloride in nanoclays on enamel

OBJECTIVE

The aim of this study is to test, in vitro, the anti-cariogenic effect of experimental hybrid coatings, with nano clays of halloysite or bentonite, loaded with sodium fluoride or with a combination of sodium fluoride and stannous chloride, respectively.

METHODOLOGY

The varnish Fluor Protector (1,000 ppm of F-) was used as positive control and no treatment was the negative control. Enamel specimens (5 mm × 5 mm) were obtained from bovine teeth. The specimens (n=10) had their surfaces divided into two halves (5 mm × 2.5 mm each), in which one half received one of the treatments (Hybrid; Hybrid + NaF; Hybrid + NaF + SnCl2; Hybrid + NaF Loaded; Hybrid + NaF + SnCl2 Loaded). The specimens were submitted to a cariogenic challenge using a biofilm model (S. mutans UA159, for 5 days). Enamel surfaces both under and adjacent to the treated area were analyzed for mineral loss and lesion depth, by transverse microradiography. The pH of the medium was measured twice a day, and the fluoride release was analyzed. Additional specimens were submitted to confocal analysis.

RESULTS

Data were statistically analyzed by two-way ANOVA followed by Tukey test (α=0.05). None of hybrid groups were able to reduce the lesion depth; the Hybrid + NaF group, however, was able to reduce mineral loss differing from the negative control (p=0.008). The groups showed no significant difference in the pH measurement and fluoride release. Confocal analysis confirmed that for all groups the biofilm growth was similar.

CONCLUSION

None of the hybrid groups reduced lesion depth, but the Hybrid + NaF group was able to promote protection against mineral loss.

Effects of microabrasion association to at-home bleaching on hydrogen peroxide penetration and color change

PURPOSE

This study aimed to quantify the penetration of hydrogen peroxide (HP) inside the pulp cavity and color change with two different concentrations of HP to at-home bleaching associated or not with enamel microabrasion (MA).

METHODS

Forty healthy premolars were randomly divided in four groups (n = 10): only HP4%, MA + HP4%, only HP10%, MA + HP10%. The concentration (μg/ml) of HP was assessed using UV-Vis spectrophotometry. The color change (ΔEab , ΔE00 and WID ) was evaluated before and one-week after bleaching. Data were evaluated for a two-way ANOVA and the Tukey's test (α = 0.05).

RESULTS

The application of MA increased the amounts of HP inside the pulp chamber when compared to without MA, as well as PH10% when compared to PH4% (p < 0.0001). PH10% showed higher WID when compared to PH4%. No significant difference was observed when ΔEab , and ΔE00 were used.

CONCLUSIONS

The enamel MA before at-home bleaching promotes greater penetration of HP, although this procedure did not significantly affect the color change.

CLINICAL SIGNIFICANCE

Since greater penetration of HP into the pulp chamber was detected when home bleaching was applied immediately after MA, the clinician should not apply home bleaching gels in the same session when MA was performed.

Evaluation of Children Caries Risk Factors: A Narrative Review of Nutritional Aspects, Oral Hygiene Habits, and Bacterial Alterations

Dental caries is one of the most common diseases—both in adults and children—that occurs due to the demineralization of enamel and dentine by the organic acids formed from bacteria present in dental plaques through anaerobic metabolism of dietary sugars. The aim of this article is to provide a guideline to assess the risk of caries by looking for the main factors involved. Literature research was performed for studies that analyzed the factors most involved in the development of child caries, such as poor oral hygiene, bad eating habits (or food disorders), and an alteration of the oral bacterial flora—with an increase of Streptococci spp., Lactobacilli spp., Candida albicans, Cryptococcus neoformans, and Candida sake. It is therefore essential to assess the risk of caries in children, based on the assessment of risk factors, in order to be able to establish preventive and/or therapeutic approaches that will reduce or stop the development of dental caries. The use of fluoride products, products made from casein phosphopeptide-amorphous calcium phosphate, substituted zinc biomimetic hydroxyapatite products, or products containing self-assembling oligopeptide SAP-P₁₁-4 are useful. In terms of the clinical approach, a communicative approach should be added to learn about the eating habits and the oral hygiene habits of the child and parents; in addition, the use of a simple method to frame the factors involved, and subsequently establish the risk of carious lesions in the child, allows the reduction of the DMFT (Decayed Missing Filled Teeth) or ICDAS (International Caries Detection and Assessment System) index on large scales.

The main criteria of dental morbidity in children under seven years of age living in regions with different fluoride content in drinking water

Relevance. Early caries is one of the most prevalent childhood diseases worldwide. Up to 32% of three-year-olds have tooth decay, the prevalence of caries in 6-7-year-old children in different cities of Russia increases to 65%, while 55.7% of children have caries of permanent teeth. In order to improve the quality of dental care, it is necessary to receive information about the prevalence and intensity of dental diseases, taking into account medical geography. Purpose – to assess caries and fluorosis incidence rate in primary teeth, to determine the hygiene index and the level of dental care for children under seven years old living in regions with different fluoride concentrations in drinking water.Materials and methods. The study conducted dental examinations of 150 children living in the South-Eastern Administrative District of Moscow aged 1 to 6 years and of 200 children living in Krasnogorsk aged 1 to 6 years. The study included the patients based on the developed inclusion criteria and informed voluntary parent consent. We entered the data into the registration card, which noted the dental formula, the prevalence and intensity of caries, the hygiene index according to Fedorov-Volodkina, the level of dental care according to P.A. Leus (1987).Results. Children living in an area with a low fluoride concentration in drinking water show the first signs of caries by the first year of age, then there is a significant increase, observed in the group of 3and 6-year-olds. The prevalence of caries in 1-year-old children living in an endemic focus of fluorosis is almost two times lower than in children living in an area with a reduced content of fluorides in drinking water, in 3-4-year-old children – 1.5 times lower, and in 5-6-year-old children 2 times lower. Along with this, 16-year-old children living in the focus of endemic fluorosis, Krasnogorsk, Moscow region, revealed fluorosis of primary teeth with a prevalence of 27%.Conclusions. The results indicates the need to increase the frequency and quality of patient education and increase the level of dental care.

A polydiacetylene (PDA) impregnated poly(vinylidene fluoride) (PVDF) membrane for sensitive detection of fluoride ions

We have developed a polydiacetylene (PDA) grafted poly(vinylidene fluoride) (PVDF) membrane for sensitive solid-phase detection of fluoride. The method was successfully used for water and toothpaste analysis and validated by ion chromatography.

Analysis of Fluoride Concentration in Toothpastes in the United Arab Emirates: Closing the Gap between Local Regulation and Practice

Background: While there is much scientific evidence supporting the benefits of fluoride for oral health, the concentration of fluoride in over-the-counter fluoride toothpaste should meet United Arab Emirates (UAE) regulations of a fluoride concentration not exceeding 0.15%. Objectives: The current study examines the fluoridated toothpaste products available on the UAE market and aims to quantify their total fluoride content. Methods: A total of 50 toothpaste products were collected and analyzed in this study. Ion Chromatography (IC) conductivity analysis was performed to determine the total fluoride content. Results: Among the 50 products tested, 10 exceeded the recommended concentration of total fluoride of less than 0.15%, while 12 had a total fluoride concentration that was less than was declared on their labels. Moreover, this study has revealed that 22 of the sampled products had a total fluoride concentration below 1000 ppm fluoride. An increased risk of higher total fluoride content was observed in the toothpaste products with monofluorophosphate active ingredients than in products with potassium nitrate/sodium fluoride and sodium fluoride (p = 0.011). Conclusions: There is a need to reassess the effectiveness of current regulations in the UAE to ensure that all fluoridated toothpastes available on the market are safe and effective for the consumer. Specifically, appropriate guidelines should be established on the basis of the risks and benefits inherent in fluoride exposure. Moreover, fluoridated toothpastes need to be subject to stricter monitoring and control regarding their safety and quality through good manufacturing practices (GMPs), education, research, and adverse event reporting.

Cationic Antimicrobial Peptides Are Leading the Way to Combat Oropathogenic Infections

Oral dental infections are one of the most common diseases affecting humans, with caries and periodontal disease having the highest incidence. Caries and periodontal disease arise from infections caused by oral bacterial pathogens. Current misuse and overuse of antibiotic treatments have led to the development of antimicrobial resistance. However, recent studies have shown that cationic antimicrobial peptides are a promising family of antibacterial agents that are active against oral pathogenic bacteria and also possess less propensity for development of antimicrobial resistance. This timely Review has a focus on two primary subjects: (i) the oral bacterial pathogens associated with dental infections and (ii) the current development of antimicrobial peptides targeting oral pathogens.

Effect of fluoridated water on dental caries and fluorosis in schoolchildren who use fluoridated dentifrice

This cross-sectional study evaluated the prevalence and severity of dental caries and fluorosis in children and adolescents using fluoridated toothpaste, from areas with and without fluoridated water. Parents of 5-year-old children and 12-year-old adolescents from neighbourhoods that are supplied with and without fluoridated water answered questionnaires for determining socio-economic and demographic characteristics and habits related to oral health. The individuals were examined, and dental caries and fluorosis were measured by dmft/DMFT and TF indexes, respectively. Descriptive, bivariate and logistic regression analyses were performed (p < 0.05). Of 692 participants, 47.7% were 5-year-olds and 52.3% were 12-year-olds. The mean dmft/DMFT in the 5-year-olds/ 12-year-olds from Exposed and Not Exposed fluoridated water groups was 1.53 (± 2.47) and 3.54 (± 4.10) / 1.53 (± 1.81) and 3.54 (± 3.82), respectively. Children (OR = 2.86, 95% CI = 1.71-4.75) and adolescents (OR = 1.95, 95% CI = 1.24-3.05), who did not consume fluoridated water, had greater caries experience. Among adolescents, there was an association between fluoridated water and the prevalence of very mild/mild fluorosis (OR = 5.45, 95% CI: 3.23-9.19) and moderate fluorosis (OR = 11.11, 95% CI = 4.43-27.87). Children and adolescents, who consumed fluoridated water, presented lower prevalence and severity of dental caries compared to those who used only fluoridated toothpaste as the source of fluoride. There is an association between water fluoridation and very mild/mild and moderate fluorosis in adolescents.

Effect of TiF4/NaF and chitosan solutions on biofilm formation and prevention of dentin demineralization

OBJECTIVE

This study evaluated the effect of experimental solutions containing TiF₄/NaF and chitosan on bacterial species of microcosm biofilm and on dentin demineralization.

DESIGN

Microcosm biofilm was produced from human saliva mixed with McBain medium (0.2% sucrose) on bovine dentin for 5 days, under 5% CO₂ and 37 °C. From the 2nd day to 5th day, the treatments were applied (1×60s/day) as following: (1) NaF (500 ppm F^-, positive control); (2) TiF₄ and NaF (TiF₄: 190 ppm Ti⁴⁺ and 300 ppm F^-; NaF: 190 ppm F^-); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPa.s, 75% deacetylation). CFU counting was performed for total microorganism, total streptococci, total lactobacilli and mutans streptococci. Dentin demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < 0.05).

RESULTS

No differences were found between the treatments with respect to CFU counting (p > 0.05). Dentin treated with TiF₄/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF₄/NaF solution, being both able to significantly reduce mineral loss.

CONCLUSION

TiF₄/NaF plus chitosan solution, at suitable pH to be clinically applicable, had no antimicrobial effect, but it was able to reduce dentin caries development under this model.

Age period cohort analysis of chewing ability in Korea from 2007 to 2018

There have been marked improvements in oral health in Korea during the past 10 years, including chewing ability. We sought to disentangle age, period, and cohort effects in chewing ability between 2007 and 2018. We analyzed data from the Korea National Health and Nutrition Examination Survey. The main variable was chewing difficulty, which was assessed among participants aged 20 years and older. APC analysis revealed three trends in chewing difficulty: (1) there was an increase in chewing difficulty starting at around 60 years of age (age effect), (2) there was a steady decrease in chewing difficulty during the observation period (period effect), and (3) chewing ability improved with each successive generation born after 1951 (cohort effect). Regarding recent improvements in chewing ability, cohort effects were somewhat more important than period effects.

In Vitro Assessment of Long-Term Fluoride Ion Release from Nanofluorapatite

The issue concerning the tooth decay is ongoing, therefore the study of materials with potential use in its prevention is crucial. This study aimed to analyze the long-term release of fluoride from synthesized nanofluorapatite in various in vitro environments for its potential use in dental materials. We placed 100 mg samples in 0.9% NaCl or deionized water and incubated them at 37 °C or 22 °C for 12 weeks. F− levels were read at 1, 3, 24, 48, 72, and 96 h, and thereafter weekly. The levels of F− released at specific time intervals, as well as their cumulative values were compared. In a solution of 0.9% NaCl at 22 °C, there were no significant differences in the amount of F− released in the assessed time intervals, while at 37 °C, the highest value was read after 24 h (0.0697 ppm + 0.0006; p < 0.05). In deionized water, the highest amount of F− at 22 °C was read after 4 weeks (0.0776 ppm + 0.0028; p < 0.05), and at 37 °C, it was also the highest after 4 weeks (0.0910 ppm + 0.0156; p < 0.05). Under the same conditions, after 5 weeks the cumulative level of F− released (0.6216 ppm + 0.0085) significantly increased (p < 0.05), when compared to the samples placed in 0.9% NaCl at 37 °C and 22 °C (0.5493 ppm + 0.0321 and 0.5376 ppm + 0.0234, respectively). FAp releases F− for a long period of time in all assessed environments, therefore it is advised to continue testing in vivo models. Due to the probable remineralization effect towards hard tooth tissues, fluorapatite can be used in the prevention and treatment of dental caries and dentin hypersensitivity.

Effect of TiF4/NaF and chitosan solutions on the development of enamel caries under a microcosm biofilm model

OBJECTIVES

To evaluate the effect of experimental solutions containing TiF₄/NaF and chitosan on bacterial species and on enamel caries prevention.

METHODS

Microcosm biofilm was produced from human saliva mixed with McBain saliva (0.2% sucrose) on bovine enamel for five days, under 5% CO₂ and 37 °C. From the second day until the end, the treatments were applied (1 × 60 s/day): (1) NaF (500 ppm F^-, positive control); (2) TiF₄ and NaF (TiF₄: 190 ppm Ti⁴⁺ and 300 ppm F^-; NaF: 190 ppm F^-); (3) similar to 2 plus 0.5% chitosan (Ch 500 mPas, 75% deacetylation); (4) phosphate buffer solution (negative control); and (5) 0.5% chitosan (Ch 500 mPas, 75% deacetylation). CFU counting was performed for total microorganism, total streptococcus, total lactobacillus and Streptococcus mutans. Enamel demineralization was measured by transverse microradiography-TMR. The data were compared using ANOVA/Tukey or Kruskal-Wallis/Dunn tests (p < .050).

RESULTS

No differences were found between the treatments with respect to CFU counting (ANOVA, p > .050). Enamel treated with TiF₄/NaF plus chitosan solution presented the lowest demineralization compared to the negative control and pure chitosan solution. On the other hand, this experimental solution did not significantly differ from TiF₄/NaF and NaF solutions, being all of them able to significantly reduce mineral loss (50-74%), but only TiF₄/NaF plus chitosan reduced lesion depth (55%) compared to the negative control (p = .001).

CONCLUSION

TiF₄/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development in 79% compared to control under this model.

CLINICAL SIGNIFICANCE

This study showed that TiF₄/NaF plus chitosan solution had no antimicrobial effect, but it was able to reduce enamel caries development under a microcosm biofilm model.

Ten-year trends in DMF-S and DMF-T in a northeast German adult population

OBJECTIVE

The aim of this study was to assess 10-year trends in coronal caries in adults aged 20-83 years using data from the two-representative population-based Studies of Health in Pomerania (SHIP-0/SHIP-Trend-0).

METHODS

Repeated cross-sectional data from 4,286 SHIP-0 and 3,913 SHIP-Trend-0 participants were analysed. Carious, filled and missing teeth/surfaces were recorded in a half-mouth design and the DMF-T/S scores and sound surfaces/teeth were calculated according to WHO criteria. Trends in DMF-T/S scores and its single components were presented stratified by age group and sex.

RESULTS

A statistically significant decline in coronal caries experience (DMF-T and DMF-S) in adults aged 20 to 83 years as well as for D-T/S components was observed. The proportion of edentulous participants was almost halved from 8.7% (SHIP-0) to 5.1% (SHIP-Trend-0), while the number of M-T declined from 4.4 to 3.5 revealing an overall clear shift to a higher retention rate of teeth. In younger adults (25-34 years) 3.8 more sound teeth (17.2 sound surfaces) were found in average in the mouth and in elderly (65-74 years) a clear shift from extracted to filled teeth was observed (M-T reduced by 5.4, while F-T increased by 4). Regarding sex differences, females had consistently on average higher MF-T/S values, but lower D-T/S values than males.

CONCLUSION

A clinically relevant drop in the severity of coronal caries experience in all adult age groups in Northeast Germany shows that not only reductions in caries experience in adolescence translated into adulthood but also later improvements led to long-term oral health.

Sodium fluoride causes oxidative damage to silkworm (Bombyx mori) testis by affecting the oxidative phosphorylation pathway

Bombyx mori was used to study the molecular mechanism of fluoride induced reproductive toxicity. In our previous study, we confirmed the physiological and biochemical effects of NaF on reproductive toxicity, and we found that the molecular mechanism of NaF induced reproductive damage may be associated with the oxidative phosphorylation pathway. To further study the function of NaF exposure on the oxidative phosphorylation pathway in the testis in Bombyx mori, and the relationship between oxidative phosphorylation and oxidative stress, we measured the changes in the main ROS (O2- and H2O2) in the testis, the activity of the main electron transport chain complex enzymes in the oxidative phosphorylation pathway and the transcription levels of the corresponding genes; we additionally performed pathological observations of the silkworm testis after exposure to 200 mg/L NaF solution for different times. The content of O2- and H2O in the silkworm gonads increased significantly at 24 h, 72 h and 120 h after NaF stress. The activity of mitochondrial complexes I, III, IV and V in the silkworm testis was significantly greater than that in the control group. RT-PCR analysis suggested that the mRNA transcription levels of NADH-CoQ1, Cyt c reductase, Cyt c oxidase and ATP synthase genes were up-regulated significantly. Histopathological investigation showed that the damage to the silkworm testis was more severe with increasing NaF exposure times. These results indicated that NaF stress affects the NADH respiratory chain of the mitochondrial electron transport chain and increases the activity of related enzyme complexes, thus destroying the balance of the electron transport chain. Subsequently, the content of ROS in cells significantly increases, thus resulting in oxidative stress reactions in cells. These results enable better understanding of the testis-damaging molecular toxicological mechanism of NaF.

Remineralization Potential and Shear Bond Strength of Surface Treated Hypomineralized Enamel in Bonding of Orthodontic Brackets: An In Vitro Study

Aim:

To investigate the effect of different conditioning methods on remineralization potential of hypomineralized enamel and its shear bond strength (SBS) to orthodontic brackets.

Materials and Methods:

An in vitro study was conducted at Mansoura University, Egypt. Eighty premolars were collected and randomly classified into four groups ( n = 20 each) as follows: Group 1. Control (sound teeth), Group 2. Demineralized, Group 3. Demineralized and treated with nanohydroxyapatite (nano-HA) varnish, Group 4. Demineralized and treated with casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) paste. To detect the rate of remineralization on the surface of treated specimens, energy dispersive X-ray (EDX) analysis was used in conjunction with the scanning electron microscope (SEM). The SBS was measured with a universal testing machine. One-way ANOVA test was carried out to analyze differences between the tested groups.

Result:

SE micrographs of Group 3 and Group 4 specimens showed smoother and less porous enamel surface than that of the Group 2 specimens. EDX analysis showed highest calcium (Ca) (25.47%) and phosphorous (P) (12.76%) values for Group 4 while Group 2 showed the lowest Ca and P values (16.96%) and (10.20%), respectively ( P < .001). Demineralized enamel showed lowest (3.70 MPa) SBS mean value compared to sound (10.69 MPa) and remineralized enamel (Group 3—9.90 MPa, Group 4—10.32 MPa) ( P < .001).

Conclusion:

Nano-HA and CPP–ACP have equal remineralizing effect on hypomineralized enamel lesions and positive influence on SBS.

Development of a new approach to diagnosis of the early fluorosis forms by means of FTIR and Raman microspectroscopy

This study is aimed at investigating the features of mineralization of the enamel apatite at initial stages of fluorosis development. Samples of teeth with intact and fluorotic enamel in an early stage of the disease development (Thylstrup-Fejerskov Index = 1-3) were studied by Raman scattering and FTIR using Infrared Microspectroscopy beamline at Australian Synchrotron equipment. Based on the data obtained by optical microspectroscopy and calculation of the coefficient R [A-type/B-type], which represents the ratio of carbonation fraction of CO32-, replacing phosphate or hydroxyl radicals in the enamel apatite lattice, the features of mineralization of enamel apatite in the initial stages of development of the pathology caused by an increased content of fluorine in the oral cavity were established. Statistical analysis of the data showed significant differences in the mean values of R [A-type/B-type] ratio between the control and experimental groups for surface layers (p < 0.01). The data obtained are potentially significant as benchmarks in the development of a new approach to preventive diagnostics of the development of initial and clinically unregistered stages of human teeth fluorosis, as well as personalized control of the use of fluoride-containing caries-preventive agents.

Comparison of Fluoride Ion Release from Fluoride Gel in Various Solvents

OBJECTIVE

The aim of this study was to determine the concentration of fluoride ions present in various solvent solutions and compare it to the label amount of fluoride concentration.

MATERIAL AND METHODS

The gel containing amine fluoride and sodium fluoride was compared to gel containing sodium fluoride only. The solvents used in this study were distilled water, redistilled water, tap water, 0.9% sodium chloride solution and the artificial saliva. The amount of fluoride ion (F^-) was determined by the use of fluoride ion-selective electrode. The ANOVA and the Post hoc Tukey's test were used. The significance level was α = 5%.

RESULTS

The differences between F^- ion release in various solvents were statistically significant (p < 0.05). The F^- ion concentrations measured in both gels' redistilled water solutions were higher than the label concentration. There was a significant difference in fluoride ion release in sodium fluoride only gel solutions. Fluoride ion release was significantly different in combined fluoride gel solutions.

CONCLUSIONS

Amine fluorides do not interact with other ions present in the solution, whereas F^- ion release from sodium fluoride alters when other ions are dissolved in the same solution. Amine fluorides deliver F^- ions for caries prevention more efficiently.

In vitro evaluation of composite containing DMAHDM and calcium phosphate nanoparticles on recurrent caries inhibition at bovine enamel-restoration margins

OBJECTIVE

Recurrent caries is a primary reason for restoration failure caused by biofilm acids. The objectives of this study were to: (1) develop a novel multifunctional composite with antibacterial function and calcium (Ca) and phosphate (P) ion release, and (2) investigate the effects on enamel demineralization and hardness at the margins under biofilms.

METHODS

Dimethylaminohexadecyl methacrylate (DMAHDM) and nanoparticles of amorphous calcium phosphate (NACP) were incorporated into composite. Four groups were tested: (1) Commercial control (Heliomolar), (2) Experimental control (0% DMAHDM + 0% NACP), (3) antibacterial group (3% DMAHDM + 0% NACP), (D) antibacterial and remineralizing group (3% DMAHDM + 30% NACP). Mechanical properties and Ca and P ion release were measured. Colony-forming units (CFU), lactic acid and polysaccharide of Streptococcus mutans (S. mutans) biofilms were evaluated. Demineralization of bovine enamel with restorations was induced via S. mutans, and enamel hardness was measured. Data were analyzed via one-way and two-way analyses of variance and Tukey's multiple comparison tests.

RESULTS

Adding DMAHDM and NACP into composite did not compromise the mechanical properties (P > 0.05). Ca and P ion release of 3% DMAHDM + 30% NACP was increased at cariogenic low pH. Biofilm lactic acid and polysaccharides were greatly decreased via DMAHDM, and CFU was reduced by 4 logs (P < 0.05). Under biofilm acids, enamel hardness at the margins was decreased to about 0.5 GPa for control; it was about 1 GPa for antibacterial group, and 1.3 GPa for antibacterial and remineralizing group (P < 0.05).

CONCLUSIONS

The novel 3% DMAHDM + 30% NACP composite had strong antibacterial effects. It substantially reduced enamel demineralization adjacent to restorations under biofilm acid attacks, yielding enamel hardness that was 2-fold greater than that of control composites. The novel multifunctional composite is promising to inhibit recurrent caries.

Tooth Enamel and its Dynamic Protein Matrix

Tooth enamel is the outer covering of tooth crowns, the hardest material in the mammalian body, yet fracture resistant. The extremely high content of 95 wt% calcium phosphate in healthy adult teeth is achieved through mineralization of a proteinaceous matrix that changes in abundance and composition. Enamel-specific proteins and proteases are known to be critical for proper enamel formation. Recent proteomics analyses revealed many other proteins with their roles in enamel formation yet to be unraveled. Although the exact protein composition of healthy tooth enamel is still unknown, it is apparent that compromised enamel deviates in amount and composition of its organic material. Why these differences affect both the mineralization process before tooth eruption and the properties of erupted teeth will become apparent as proteomics protocols are adjusted to the variability between species, tooth size, sample size and ephemeral organic content of forming teeth. This review summarizes the current knowledge and published proteomics data of healthy and diseased tooth enamel, including advancements in forensic applications and disease models in animals. A summary and discussion of the status quo highlights how recent proteomics findings advance our understating of the complexity and temporal changes of extracellular matrix composition during tooth enamel formation.