Decline in Dental Fluorosis Severity during Adolescence: A Cohort Study

Dietary Fluoride Exposure During Early Childhood and Its Association with Dental Fluorosis in a Sample of Mexican Adolescents

Dental fluorosis indicates past fluoride intake. People living in Mexico City are exposed to fluoridated salt, which contributes significantly to fluoride intake. This study aimed to (1) estimate fluoride intake during early childhood and fluorosis prevalence in permanent teeth in adolescence and (2) identify intake windows associated with higher fluorosis scores in upper central incisors (UCIs). We included 432 participants from the ELEMENT project (Early-Life Exposures in Mexico to Environmental Toxicants), with data on fluoride intake at ages 1-5 and fluorosis (TFI) at adolescence. Median intakes ranged from 0.56 at age 1 to 1.14 mg/day at age 5, exceeding recommendations. All adolescents had some level of fluorosis, predominantly mild (62% with TFI 2). For every 0.1 mg of daily fluoride intake at age 1, the odds of higher TFI in UCIs were 1.08 [95% CI: 1.00-1.17]. At age 2, the odds were marginally significant [OR: 1.07; 95% CI: 1.00-1.16]. In conclusion, for participants of ELEMENT: (1) fluoride intake during early childhood exceeded recommendations and the prevalence of mild fluorosis in adolescence was high, and (2) fluorosis in UCIs was associated with dietary exposure during the first two years of life and may be used in future ELEMENT studies as exposure biomarkers.

Multi-modal management of dental fluorosis in a family: A case series

RATIONALE

This case series addresses the management of dental fluorosis, a condition caused by excessive fluoride intake during tooth development. The 3 patients in this report, all from the same family, exhibited varying degrees of dental fluorosis, impacting both aesthetics and function. Treatments ranged from conservative approaches like bleaching and macro-abrasion to more extensive restorative options like veneers and crowns, aiming to improve dental appearance and oral health.

PATIENT CONCERNS

All 3 patients were concerned with the discoloration and aesthetic issues caused by dental fluorosis. Each expressed a desire to improve their smile and address any functional impacts on their teeth.

DIAGNOSES

The patients were diagnosed with dental fluorosis of varying severity. Diagnosis was made based on clinical examination, history of fluoride intake, and radiographs. The condition was classified using the Thylstrup and Fejerskov index, which assesses the extent of fluorosis based on enamel opacity, pitting, and discoloration.

INTERVENTIONS

Case 1 (moderate fluorosis): The patient underwent home bleaching, composite restorations, and the application of laminate veneers after gingivectomy. Case 2 (moderate-to-severe fluorosis): The patient had several teeth extracted due to failed endodontic treatment, followed by the placement of lithium disilicate crowns and a zirconia bridge. Case 3 (mild fluorosis): This patient received in-office and at-home bleaching, followed by macro-abrasion and resin infiltration to improve the appearance of white spots.

OUTCOMES

Each treatment successfully addressed the functional and aesthetic concerns of the patients. The use of bleaching, veneers, crowns, and resin infiltration significantly improved their smiles. All patients reported satisfaction with the results, achieving a more natural tooth appearance and improved confidence in their dental health.

LESSONS

This case series highlights the importance of a multi-modal, individualized approach to managing dental fluorosis. By tailoring treatment to the severity of the condition, aesthetic and functional improvements were consistently achieved across different fluorosis severities. Dental fluorosis management should prioritize minimally invasive options while maintaining a focus on long-term aesthetic and functional restoration.

Ultrastructural evaluation of adverse effects on dentine formation from systemic fluoride application in an experimental mouse model

AIM

Fluoride is widely used in dentistry for its caries prevention. To reduce dental caries, the optimal fluoride concentration of public water supplies in the United States is 0.7 ppm. However, excessive systemic fluoride consumption can lead to dental/enamel fluorosis. Numerous studies have explored the effects of fluoride on enamel and enamel-forming cells. However, research on systemic fluoride's impact on dentine is limited, particularly the effect of fluoride on the structure of the dentine-pulp complex. Therefore, this study aimed to identify how excessive fluoride affects dentine microstructure using an experimental mouse model.

METHODOLOGY

C57BL6/J male mice (6-9 weeks old) were randomized into four groups (Fluoride at 0, 50, 100, or 125 ppm in drinking water) (n = 4/group). Mice were provided water ad libitum for 6 weeks along with fluoride-free food. Thereafter, mandibular incisors were analysed. Enamel phenotypes were evaluated using light microscopy and quantitative light-induced fluorescence (QLF) to measure fluorosis levels. Dentine morphology was evaluated using micro-CT, scanning electron microscopy (SEM), SEM-EDX (energy-dispersive X-ray), microhardness test and histological imaging. Data were analysed using one-way ANOVA with Dunnett's multiple comparisons as a post hoc test and the Kruskal-Wallis test with Dunn's multiple comparisons post hoc test (p < .05).

RESULTS

Mice treated with fluoride at 50-125 ppm developed enamel hypoplasia in their erupting incisors and micro-CT imaging revealed that fluoride 125 ppm caused external resorption of the growing incisor. Dentine mineral density, dentine volume decreased compared with the 0 ppm control, while pulp volume increased compared with the 0 ppm control group. SEM showed wider predentine layer and abnormalities in calcified matrix vesicles derived from odontoblasts in fluoride 100 and 125 ppm groups. Vickers microhardness of dentine significantly decreased in the high-dose group. Fluoride-induced dentine hypoplasia in a dose-dependent manner. Histological evaluation showed excessive fluoride 125 ppm induced micro abscess formation and inflammatory cell infiltration. Fluoride induced dentine dysplasia with a dentine microstructure resembling hypophosphatasia.

CONCLUSIONS

High doses of systemic fluoride can cause dentine dysplasia. Both three-dimensional and microstructural analyses showed the structural, chemical and mechanical changes in the dentine and the mineralized tissue components, along with external resorption and pulp inflammation.

Kinetics of fluoride after brushing with the no-rinse method

BACKGROUND

Fluoride plays a vital role in preventing dental caries, with its addition to oral care products significantly promoting oral hygiene. A no-rinse brushing method aims to increase fluoride retention in the oral cavity, as rinsing with water decreases fluoride levels in saliva, which could affect remineralization. While the no-rinse brushing method holds promise for improving fluoride retention in the oral cavity, critical inquiries persist regarding its safety. This study investigated the kinetics of oral fluoride and potential risks to fully assess its effectiveness and implications for oral health.

METHODS

Ten healthy adults participated in a crossover study comparing the no-rinse with the rinse method. All subjects followed American Dental Association (ADA) brushing guidelines. Levels of fluoride in saliva (supernatant and sediment) and urine were measured over time, and plasma fluoride was measured one hour after brushing. Pharmacokinetic parameters were also calculated from the data.

RESULTS

Participants using the no-rinse method had higher fluoride levels in supernatant immediately and up to 30 min post-brushing compared to the rinse method. Fluoride levels in sediment were higher only immediately after brushing. The total fluoride concentration in saliva remained elevated for up to 5 min with the no-rinse method. Systemic fluoride absorption showed no significant difference between the two methods based on blood and urine analysis.

CONCLUSION

This research indicates that the no-rinse method can enhance fluoride retention in the oral cavity for up to 30 min after a single brushing. In addition, our findings suggest that this method does not significantly influence systemic fluoride levels or toxicity.

REGISTRY

Thai Clinical Trials Registry, TCTR ( http://thaiclinicaltrials.org ).

CLINICAL TRIAL REGISTRATION NUMBER

TCTR20231104001 (4/11/2023).

Generalized permanent dentition fluorosis severity becomes less evident over time among a birth cohort

Objectives

There are relatively few cohort studies which have examined changes in fluorosis appearance over time, and none of these have assessed changes in generalized fluorosis. In this analysis, we quantified and assessed changes in multiple measures of generalized fluorosis severity through childhood, adolescence, and young adulthood.

Methods

Participants were from the Iowa Fluoride Study, a birth cohort recruited from 1992 to 1995. Permanent dentition fluorosis exams were carried out at ages 9, 13, 17, and 23 years using the Fluorosis Risk Index (FRI). Generalized fluorosis was assessed using mean FRI scores at the tooth- and person-level as well as a five-category measure of generalized fluorosis. Generalized fluorosis prevalence and severity was summarized at each time point and differences in adjacent time points were assessed using gamma statistics, signed-rank tests, and plotting changes in generalized fluorosis between adjacent time points.

Results

We observed a statistically significant decline in the percentage of non-zero mean FRI scores at later exam ages at both the person- and tooth-levels. Based on our five-category generalized fluorosis measure, there were 34.0%-54.1% of participants with generalized fluorosis at baseline for each tooth group, and these percentages declined to 8.9%-27.2% at the age 23-year exam.

Conclusions

We observed a statistically significant decline in generalized fluorosis severity scores and overall prevalence at later exam ages across all three measures of generalized fluorosis severity. This trend should be accounted for when estimating the prevalence of fluorosis in a population using fluorosis severity data collected in children and adolescents.

Analyzing dental fluorosis data using a novel Bayesian model for clustered longitudinal ordinal outcomes with an inflated category

We propose a Bayesian hurdle mixed-effects model to analyze longitudinal ordinal data under a complex multilevel structure. This research was motivated by the dataset gathered from the Iowa Fluoride Study (IFS) in order to establish the relationships between fluorosis status and potential risk/protective factors. Dental fluorosis is characterized by spots on tooth enamel and is due to ingestion of excessive fluoride intake during enamel formation. Observations are collected from multiple surface zones on each tooth and on all available teeth of children from the studied cohort, which are longitudinally observed at ages 9, 13, and 17. The data not only exhibit a complex hierarchical structure, but also have a large proportion of zero values that are likely to follow different statistical patterns from non-zero categories. Therefore, we develop a hurdle model to consider the zero category separately, while a proportional odds model is used for the positive categories. The estimated parameters are obtained from a Gibbs sampler implemented by the OpenBUGS software. Our model is compared with two popular methods for ordinal data: the proportional odds model and the partial proportional odds model. We perform a comprehensive analysis of the IFS data and evaluate the accuracy and effectiveness of our methodology through simulation studies. Our discoveries provide novel insights to statisticians and dental practitioners about the associations between patient and clinical characteristics and dental fluorosis.

Fluoridated water impact on tooth decay and fluorosis in 17-20-year-olds exposed to fluoride toothpaste

OBJECTIVE

To determine the impact of water fluoridation on the prevalence and severity of dental caries and fluorosis in individuals aged 17-20 years exposed to fluoride toothpaste.

METHODS

The study population consisted of 660 students from public schools, residents of areas supplied with fluoridated water (exposed group) or not (not exposed group). Students from both groups had access to fluoride toothpaste throughout life. A questionnaire about socioeconomic demographic aspects, conditions related to access and exposure to fluoridated water, and habits related to oral health was applied. Dental caries was measured by the DMFT index and dental fluorosis by the TF index. The chi-square test, t test, and subsequently logistic regression were applied for data analysis.

RESULTS

Caries experience (DMFT≠0) was significantly higher in students from areas not exposed to fluoridated water, after adjustments to clinical conditions, demographic socioeconomic profile, and hygiene habits. The DMFT mean (±SD) was significantly higher in students from areas not exposed to fluoridated water than exposed (3.83 [±3.28] and 2.48 [±2.71] respectively). The prevalence of very mild/mild and moderate fluorosis was 41.1% and 21% for students either exposed to fluoridated water or not, respectively.

CONCLUSION

Exposure to fluoridated water was associated with a lower prevalence and severity of tooth decay, in spite of the use of fluoridated toothpaste. The prevalence of dental fluorosis at all levels was higher in fluoridated areas, however, in both groups, there were few cases with esthetic implications.

Comprehensive Management of Severe Dental Fluorosis with Adhesively Bonded All-Ceramic Restorations

Dental fluorosis is a common disorder caused by excessive fluoride intake during tooth development. The esthetic consequences of dental fluorosis can negatively affect oral health-related quality of life and have lasting psychosocial effects. In severe cases, where the fluorosed enamel is prone to chipping, flaking, and developing caries, minimally invasive procedures are ineffectual and a more substantial restorative approach is required to restore optimal function and esthetics. However, no definitive guidelines exist for the management and treatment of severe dental fluorosis due to the limited evidence available in the literature. This case report describes the full-mouth rehabilitation of a patient with severe dental fluorosis utilizing adhesively bonded all-ceramic crowns, veneers, and overlays. The successful follow-up on this case indicates that adhesively bonded restorations may provide a viable option in the functional and esthetic management of severely fluorosed dentition.

Clinical changes in the severity of dental fluorosis: a longitudinal evaluation

BACKGROUND

Dental fluorosis (DF) has been one of the most prevalent pediatric dental conditions associated with aesthetic concern and treatment needs. This study aimed to identify the longitudinal clinical change in the severity of DF in 8-12-year-old children and its association with gender, age, severity, and tooth type.

METHODS

This observational study assessed the dental aspects of the 92 Colombian children in 2015 (mean age at beginning 9.71 years ± 1.23) and 2018 (mean age 13.69 years ± 1.41), from an area with high DF prevalence. DF was recorded in all permanent teeth by two calibrated examiners using the Thylstrup and Fejerskov Index (TFI). DF severity change (maximum-TFI-score) was analyzed with descriptive analysis at the tooth level. Associated factors were evaluated with the generalized linear model, binomial family, and logarithmic link function.

RESULTS

TFI scores ranged between 1 (very mild) to 6 (severe), being score 2 (41.7%) the most prevalent. After three years, 29.6% of the teeth presented score reduction, 24.1%, increased and 46.3% did not change; the significant association was related to increasing of the basal TFI = 1 score (44.2%) (RR = 9.7; 95% CI 1.7-56.5; p = 0.01) and with canines, premolars and second-permanent-molars teeth group (RR = 3.3; 95% CI 1.9-5.6; p = 0.005).

CONCLUSION

The present study based on clinical features about DF confirms the dynamic post-eruptive nature of this condition. After three years of follow-up, a considerable proportion of the teeth changed to a higher score. Furthermore, the canines, premolars, and second-permanent-molars showed a higher incidence of an increase in severity of TFI score.

Dental Fluorosis according to Birth Cohort and Fluoride Markers in an Endemic Region of Colombia

Objectives

To analyze changes in the dental fluorosis (DF) incidence according to a birth cohort and explore current exposure to DF in a case series.

Methods

Repeated cross-sectional study of two periods: 2015 and 2018. Two standardized examiners registered DF using the Thylstrup-Fejerskov index in permanent teeth of children aged 7–18 years. Period and birth cohort frequencies were estimated by a generalized linear model, binomial family, and logarithmic link function. Period estimates are presented as prevalence ratios (PR) and birth cohort estimates as cumulative incidence ratios (RR); 95% confidence intervals and P values are reported. In a subsample of 37 volunteers (12.29 ± 2.63 years), the fluoride (F) concentration in toenails was measured using the HMDS diffusion method and an ion-specific electrode. Other samples from the local environment such as food, soil, and coal were also collected.

Results

In 274 children, we found that nonsignificant increases between periods (PR = 1.17; 95% CI: 0.89–1.55) were not explained by birth cohort effects. A total of 37.8% of the subsample had a toenail F concentration ≥2 μg F/g. The salty snacks and seasoning had the highest F concentrations among local environmental samples.

Conclusion

In this population with a high DF frequency according to birth cohort and the evaluated period, the study of soil, coal, and food samples indicated a continued F exposure. F concentration found in the toenails shows a moderate F exposure; nearly a third of the children and adolescents exceeded the adopted threshold of 2 μg F/g. It is important to monitor and explore changes in exposure in highly affected population.

Impact of Reducing Water Fluoride on Dental Caries and Fluorosis

Guidance intended to reduce fluoride toothpaste ingestion in early childhood was introduced in Ireland in 2002. In 2007, water fluoride concentration was adjusted from 0.8-1.0 to 0.6-0.8 ppm. The objective of this study was to determine the difference in caries and fluorosis levels following introduction of these 2 policy measures. A before-and-after study compared caries and fluorosis in random samples of 8-y-olds in Dublin (n = 707) and Cork-Kerry (n = 1148) in 2017 with 8-y-olds in Dublin (n = 679) and Cork-Kerry (n = 565) in 2002. Dentinal caries experience (primary teeth, d_3vcmft(cde)) and fluorosis (permanent teeth, Dean's index of very mild or higher) were clinically measured. Lifetime exposure to community water fluoridation (CWF) was classified as "full CWF"/"no CWF." Effect of examination year on caries prevalence and severity and fluorosis prevalence was assessed using multivariate regression adjusting for other explanatory variables. There was little change in commencement of fluoride toothpaste use at ≤24 mo following introduction of toothbrushing guidance. Among children with full CWF, there was no statistically significant difference in caries prevalence or severity between 2017 and 2002. In 2017, caries prevalence was 55% in Dublin (full CWF) and 56% in Cork-Kerry (full CWF), and mean d_3vcmft(cde) among children with caries was 3.4 and 3.7, respectively. Caries severity was less in 2017 (mean 4.2) than 2002 (mean 4.9) among children with no CWF (P = 0.039). The difference in caries severity between children with full CWF and no CWF was less in 2017 than in 2002 (interaction P = 0.013), suggesting a reduced benefit for CWF in 2017. In 2017, fluorosis prevalence was 18% in Dublin (full CWF) and 12% in Cork-Kerry (full CWF). Fluorosis was predominantly "very mild" with no statistically significant difference between 2017 and 2002. CWF at 0.6 to 0.8 ppm is an effective caries-preventive measure. Results suggested low uptake of toothbrushing guidance, a reduced caries-preventive effect for CWF in primary teeth, and no reduction in fluorosis following introduction of the policy measures.