Multi-scale characterization of Developmental Defects of Enamel and their clinical significance for diagnosis and treatment.

Developmental Defects of Enamel (DDE) such as Dental Fluorosis (DF) and Molar Incisor Hypomineralization (MIH) are a major public health problem. Their clinical aspects are extremely variable, challenging their early and specific diagnosis and hindering progresses in restorative treatments. Here, a combination of macro-, micro- and nano-scale structural and chemical methods, including, among others, Atom Probe Tomography recently applied on tooth enamel, were used to study and compare MIH, DF and healthy teeth from 89 patients. Globally, we show that DF is characterized by an homogenous loss of mineral content and crystallinity mainly disrupting outside layer of enamel, whereas MIH is associated with localized defects in the depth of enamel where crystalline mineral particles are embedded in an organic phase. Only minor differences in elemental composition of the mineral phase could be detected at the nanoscale such as increased F and Fe content in both severe DDE. We demonstrate that an improved digital color measurement of clinical relevance can discriminate between DF and MIH lesions, both in mild and severe forms. Such discriminating ability was discussed in the light of enamel composition and structure, especially its microstructure, organics presence and metal content (Fe, Zn). Our results offer additional insights on DDE characterization and pathogenesis, highlight the potentiality of colorimetric measurements in their clinical diagnosis and provide leads to improve the performance of minimally invasive restorative strategies. STATEMENT OF SIGNIFICANCE: Developmental Defects of Enamel (DDE) are associated to caries and tooth loose affecting billions of people worldwide. Their precise characterization for adapted minimally invasive care with optimized materials is highly expected. Here In this study, first we propose the use of color parameters measured by a spectrophotometer as a means of differential clinical diagnosis. Second, we have used state-of-the-art techniques to systematically characterize the structure, chemical composition and mechanical optical properties of dental enamel teeth affected by two major DDE, Dental Fluorosis (DF) or Molar Incisor Hypomineralization (MIH). We evidence specific enamel structural and optical features for DF and MIH while chemical modifications of the mineral nanocrystals were mostly correlated with lesion severity. Our results pave the way of the concept of personalized dentistry. In the light of our results, we propose a new means of clinical diagnosis for an adapted and improved restoration protocol for these patients.

Bond strength comparison among 10-MDP-containing and non-10-MDP-Containing adhesives in different degrees of dental fluorosis / Comparación de fuerza de unión entre adhesivos que contienen y no contienen 10-MDP en diferentes grados de fluorosis dental

Dental fluorosis can cause changes in the enamel surface, conditioning its functionality and esthetics. The application of dental adhesives is a treatment option; however, their use on fluorotic teeth can result in limitations. The aim of this study was to compare the shear bond strength of two different adhesives, one with 10-MDP and one without 10-MDP, in different degrees of dental fluorosis.This is an in vitro study on dental enamel samples, a total of 180 samples with the inclusion criteria were treated, randomly divided into two groups of 90, according to the type of dental adhesive, where each group was again divided into three groups of 30 samples, representing different degrees of dental fluorosis according to the Thylstrup-Fejerskov index (Group I: TF1 and TF2; Group II: TF3; Group III: TF4). Normality tests, two-factor ANOVA, and post-hoc tests were used to determine differences between the groups, with a significance level of 95%. As results, a statistically significant difference was shown between the use of dental adhesive with 10-MDP and the three groups of dental fluorosis (p=0.011), in addition, a Tukey post-hoc test on the groups treated with 10-MDP adhesive revealed a statistically significant difference between group I versus group II, and group I versus group III, (p=<0.05). It is concluded that the use of adhesive systems with 10-MDP presents a better shear bond strength on enamel with dental fluorosis grades I and II in the Thylstrup-Fejerskov index.

La fluorosis dental puede ocasionar cambios en la superficie del esmalte, condicionando su funcionalidad y estética, la aplicación de adhesivos dentales es una opción de tratamiento, sin embargo, su uso en dientes fluoroticos puede resultar en limitaciones. El objetivo de este estudio consistió en comparar la fuerza de adhesión a la cizalladura de dos diferentes adhesivos, uno con 10-MDP y otro sin 10-MDP, en diferentes grados de fluorosis dental. Se trata de un estudio in vitro en muestras de esmalte dental, un total de 180 muestras con los criterios de inclusión fueron tratadas, aleatoriamente divididas en dos grupos de 90, de acuerdo al tipo de adhesivo dental, donde cada grupo fue dividido nuevamente en tres grupos de 30 muestras, representando diferentes grados de fluorosis dental según el índice de Thylstrup- Fejerskov (Grupo I: TF1 y TF2; Grupo II: TF3; Grupo III: TF4). Para determinar diferencias entre los grupos se utilizaron pruebas de normalidad, ANOVA de dos factores, y pruebas post-hoc, con un nivel de significancia de 95%. Como resultados, se mostró una diferencia estadísticamente significativa entre el uso de adhesivo dental con 10- MDP y los tres grupos de fluorosis dental (p=0.011), además, una prueba post hoc de Tukey sobre los grupos tratados con adhesivo 10-MDP revelaron una diferencia estadísticamente significativa entre el grupo I frente al grupo II, y el grupo I frente al grupo III, (p=<0.05) Se concluye que el uso de sistemas adhesivos con 10-MDP presentan una mejor resistencia de adhesión al cizallamiento en esmalte con grados de fluorosis dental I y II en el índice de Thylstrup-Fejerskov

Solução estética conservadora em paciente jovem com fluorose: clareamento e microabrasão: relato de caso / Conservative aesthetic solution in a young patient with fluorosis: whitening and microabrasion: case report

Introdução: a fluorose constitui uma patologia que afeta os dentes desencadeada pelo excesso de ingestão de flúor. Sua manifestação ocorre a nível de esmalte na presença de manchas ou defeitos anatômicos. Objetivo: relatar o manejo clínico de um paciente com fluorose tratado com procedimento minimamente invasivo. Relato do caso: paciente do sexo feminino, 18 anos, apresentando queixas estéticas clinicamente observadas na vestibular dos dentes, com diagnóstico de lesões fluoróticas. Foi executado protocolo de dessensibilização com Ultra EZ por 5 min e aplicação do Verniz (Enamelast Fluoride) previamente ao tratamento clareador. Foram realizados duas sessões de clareamento com peróxido de hidrogenio 35% (DMC) por 45 min com intervalo de sete dias entre elas. Imediatamente após a segunda sessão de clareamento, foi realizado microabrasão com pasta abrasiva Whitness RM (FGM) e taça de borracha com fricção por 20 segundos. Resultados: o tratamento clareador associado a técnica da microabrasão do esmalte demonstrou resultado estético favorável, microinvasivo e eficaz no tratamento da fluorose. Conclusão: a associação dos tratamentos resolveu o problema estético da paciente de forma rápida e segura, conservando a estrutura dentária.

Introduction: fluorosis is a pathology that affects teeth triggered by excess fluoride intake. Its manifestation occurs at the enamel level in the presence of stains or anatomical defects. Objective: to report the clinical management of a patient with fluorosis treated with a minimally invasive procedure. Case report: female patient, 18 years old, presenting aesthetic complaints clinically observed in the buccal of the teeth, with a diagnosis of fluorotic lesions. A desensitization protocol was performed with Ultra EZ for 5 min and Varnish (Enamelast Fluoride) was applied prior to the bleaching treatment. Two bleaching sessions were performed with 35% hydrogen peroxide (DMC) for 45 min, with an interval of seven days between them. Immediately after the second bleaching session, microabrasion was performed with Whitness RM abrasive paste (FGM) and a rubber cup with friction for 20 seconds. Results: The bleaching treatment associated with the enamel microabrasion technique demonstrated a favorable, microinvasive and effective esthetic result in the treatment of fluorosis. Conclusion: the combination of treatments solved the patient's aesthetic problem quickly and safely, preserving the dental structure.

Are there associations between the occurrence of dental fluorosis and the experience of dentine hypersensitivity? A cross-sectional study.

Objectives: Associations between the occurrence of dentine hypersensitivity (DH) and dental fluorosis (DF) have been suggested. Testing this association requires studies among populations with both conditions. This study aimed to determine the association between DF and the experience of DH among a population endemic for DF. Methods: This was a cross-sectional study conducted in 2021 over 6 months among 428 adult patients. Participants' demographics were collected, followed by verbal screening for DH and oral examinations. Clinical assessment for DH was carried out by tactile and evaporative methods. The presence and severity of DF were also assessed using the Thylstrup and Fejerskov Index. Data analysis included Chi-square and correlation statistics to assess the presence and strength of associations. Results: The overall prevalence of DH was 31.1%. A higher proportion (41.1%, P < 0.001) of participants with DF had DH than those without DF. The association between DH and DF was minimal but statistically significant (r = 0.174, P < 0.001). Among those with DF, the prevalence of DH was highest in participants with severe fluorosis (50%, P = 0.740). The proportion of sensitive teeth to the teeth examined was significantly higher (P < 0.0001) for participants with DF (289/4167, 6.9%) than participants without DF (267/6758, 4%). This proportion was also highest for severe DF (20/254, 7.9%, P = 0.572) than the mild and moderate forms. Conclusion: DH was more prevalent among individuals with DF. The prevalence of DH was not dependent on the severity of DF.

A comprehensive review on endemic and experimental fluorosis in sheep: Its diverse effects and prevention.

Fluoride is a natural element widely distributed in the environment and plays an important role in the growth of humans and animals. However, in many species, high concentrations of fluoride induce several problems, such as dental, skeletal, and non-skeletal fluorosis. Sheep living in endemic areas are sensitive to the chronic toxicity of fluoride, and they have been found to suffer not only from teeth and bone problems but also from other organs. Studies indicating the chronic harmful effects of fluoride on teeth, bones, blood biochemical parameters, kidney, liver, heart, reproductive system and growth in sheep have been clearly summarized in this review. Besides, this work also includes updated progress in terms of prevention or reduction of fluoride toxicity in this species.

Diagnosis of Dental Fluorosis Using Micro-Raman Spectroscopy Applying a Principal Component-Linear Discriminant Analysis.

Dental fluorosis is an irreversible condition caused by excessive fluoride consumption during tooth formation and is considered a public health problem in several world regions. The objective of this study was to evaluate the capability of micro-Raman spectroscopy to classify teeth of different fluorosis severities, applying principal component analysis and linear discriminant analysis (PCA-LDA), and estimate the model cross-validation accuracy. Forty teeth of different fluorosis severities and a control group were analyzed. Ten spectra were captured from each tooth and a total of 400 micro-Raman spectra were acquired in the wavenumber range of 250 to 1200 cm-1, including the bands corresponding to stretching and bending internal vibrational modes ν1, ν2, ν3, and ν4 (PO43-). From the analysis of the micro-Raman spectra an increase in B-type carbonate ion substitution into the phosphate site of the hydroxyapatite as fluorosis severity increases was identified. The PCA-LDA model showed a sensitivity and specificity higher than 94% and 93% for the different fluorosis severity groups, respectively. The cross-validation accuracy was higher than 90%. Micro-Raman spectroscopy combined with PCA-LDA provides an adequate tool for the diagnosis of fluorosis severity. This is a non-invasive and non-destructive technique with promising applications in clinical and epidemiological fields.

Diagnosis of Fluorosis by Analysis of Fluoride Content in Body Fluids Using Ion Selective Electrode Method.

Analysis of fluoride in body fluids (urine and serum) is essential for fluorosis diagnosis. Although 24-h urine collection is adopted to assess community defluoridation/fluoride supplementation program/research studies, but not feasible for Clinical/Pathological laboratories. Patients are reluctant to bring 24-h urine samples. Hence, spot urine samples are collected in clean, dry polypropylene bottles (not glass) without any preservative and analyzed on the same day by the Ion analyzer (ISE method). Equal volumes of Total Ionic Strength Adjustment Buffer (TISAB) solution are then added with body fluids before analysis and mixed well to eliminate interference from other ions besides pH adjustment and to provide a constant ionic strength. Results are reported as mg of Fluoride/l (ppm). High fluoride level in body fluids is an indication of confirmed cases of fluorosis. Two interventions, e.g. withdrawal of fluoride intake and intake of nutritive diet was introduced for prevention and control of fluorosis. The present study is to provide useful guidelines for monitoring of fluorosis disease in human beings, those who are at the risk of fluoride exposure.

Structural changes in the oral microbiome of the adolescent patients with moderate or severe dental fluorosis.

Dental fluorosis is a very prevalent endemic disease. Although oral microbiome has been reported to correlate with different oral diseases, there appears to be an absence of research recognizing any relationship between the severity of dental fluorosis and the oral microbiome. To this end, we investigated the changes in oral microbial community structure and identified bacterial species associated with moderate and severe dental fluorosis. Salivary samples of 42 individuals, assigned into Healthy (N = 9), Mild (N = 14) and Moderate/Severe (M&S, N = 19), were investigated using the V4 region of 16S rRNA gene. The oral microbial community structure based on Bray Curtis and Weighted Unifrac were significantly changed in the M&S group compared with both of Healthy and Mild. As the predominant phyla, Firmicutes and Bacteroidetes showed variation in the relative abundance among groups. The Firmicutes/Bacteroidetes (F/B) ratio was significantly higher in the M&S group. LEfSe analysis was used to identify differentially represented taxa at the species level. Several genera such as Streptococcus mitis, Gemella parahaemolysans, Lactococcus lactis, and Fusobacterium nucleatum, were significantly more abundant in patients with moderate/severe dental fluorosis, while Prevotella melaninogenica and Schaalia odontolytica were enriched in the Healthy group. In conclusion, our study indicates oral microbiome shift in patients with moderate/severe dental fluorosis. We identified several differentially represented bacterial species enriched in moderate and severe fluorosis. Findings from this study suggests that the roles of these bacteria in oral health and related diseases warrant more consideration in patients with moderate and severe fluorosis.

Does dental fluorosis affect electric pulp test response and/or optimum probe placement site?

The placement site of electric pulp tester (EPT) probe on the tooth affects the threshold values obtained. The aim of this study was to determine and compare threshold levels and appropriate placement sites for EPT probe on fluorotic and normal teeth. Equal numbers of fluorotic and non-fluorotic maxillary central incisors of 40 subjects were assessed. The mean of three threshold readings from an EPT was taken from the labial surface at the incisal edge, incisal third, middle third and cervical third. Kruskal-Wallis and Friedman ANOVA followed by post hoc tests were used to compare threshold scores. Significantly higher thresholds were recorded for fluorotic teeth at the incisal edge and incisal third. The lowest thresholds were obtained for the incisal edge in both fluorotic and non-fluorotic teeth when compared to the cervical third. There was no statistically significant difference among corresponding test sites between the genders and age groups.

Epidemiology of Erosive Tooth Wear, Dental Fluorosis and Molar Incisor Hypomineralization in the American Continent.

Non-carious dental lesions such as developmental defects of enamel (DDE) and erosive tooth wear (ETW) are the subject of intensive research. This paper aims to give perspectives on both DDE, including dental fluorosis and molar incisor hypomineralization (MIH), and ETW, presenting epidemiological data from the Americas and associated diagnostic aspects. Besides, it is important to present evidence to guide the clinical assessment process, supporting the clinicians' management decisions towards better oral health of their patients. The overall increase in the worldwide prevalence of non-carious lesions discussed in this this paper may reflect the need of perceptual changes. Although the number of publications related to these conditions has been increasing in the last years, there is still a need for clinical diagnostic and management awareness to include these conditions in routine dental practice. Besides, it is important to provide recommendations for standardized clinical assessment criteria, improving the process and helping clinicians' adherence. In this sense, this paper discusses the most commonly implemented indices for each condition. Thus, despite the wide range of diagnostic indices, BEWE is proposed to be the index recommended for ETW assessment, Dean or Thylstrup & Fejerskov indices for fluorosis and preferably the EAPD criteria (or modified DDE index) for MIH. Overall, non-carious lesions are a growing concern, and it is important to implement preventive measures that control their severity and progression, and accurate diagnosis by the dental clinician.

Dental Fluorosis: the Risk of Misdiagnosis-a Review.

Fluoride has been considered as the single factor most frequently responsible for causing enamel mottling. However, in humans, either endogenous and/or exogenous factors not related to fluoride exposure may also cause enamel mottling. In this sense, various studies in the international literature have reported severe mottling of the teeth that could not be attributed to fluoride exposure. Thus, misdiagnosis of non-fluoride-induced enamel defects may occur frequently. Reports of unexpectedly high population prevalence and individual cases of fluorosis, where such diagnoses are irreconcilable with the identified fluoride history, highlight the necessity for a more precise definition and diagnosis of dental fluorosis. Also, a more discriminating diagnostic procedure is suggested. Particularly, positive identification of environmental fluoride levels to which the communities and individuals are exposed shall be developed before the confirmation of a diagnosis of fluorosis. It is considered that a more critical methodology for the diagnosis of fluorosis will be helpful in the rational use and control of fluorides for dental health, and in the identification of factors that may induce enamel defects.

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.

Infiltrantes para tratamiento estético de lesiones de manchas blancas por fluorosis: Reporte de caso / Infiltrants for Aesthetic Treatment of White Spots Lesions by Fluorosis: Case Report

Resumen La fluorosis dental es una anomalía en el desarrollo del esmalte debido a la excesiva ingesta de flúor durante la formación de los tejidos dentales, y se caracteriza principalmente por la hipomineralización y mayor porosidad de la estructura del esmalte. Muchas veces las manchas ocasionadas por la fluorosis dental pueden comprometer la estética del paciente y afectar su autoestima. En años recientes ha sido desarrollado una nueva generación de materiales odontológicos conocida como infiltrantes resinosos, que básicamente son resinas de baja viscosidad que infiltran y paralizan la progresión de las lesiones cariosas incipientes no cavitadas. Cuando infiltrantes resinosos han sido utilizados para detener las lesiones cariosas se ha verificado que también producen cambios en la apariencia de la mancha blanca, atenuándola o tornándola imperceptible. El presente artículo describe un reporte de caso del uso de infiltrantes resinosos para tratamiento estético de lesiones de manchas blancas ocasionadas por fluorosis.

Abstract Dental fluorosis is an abnormality in the development of enamel due to the excessive intake of fluoride during formation of dental tissues, mainly characterized by hypomineralization and increased porosity of the enamel structure. Oftenly the spots caused by dental fluorosis can compromise the aesthetics of the patient and affect their self-esteem. In recent years a new generation of dental materials has been developed, known as resin infiltrants, which are basically low viscosity resins that infiltrate and paralyze the progression of incipient non cavitated carious lesions. When resin infiltrants have been used to stop carious lesions it has been verified that they also produce changes in the appearance of white spots, masking or making them imperceptible. The present article describes a case report of the use of resin infiltrants for aesthetic treatment of white spot lesions caused by fluorosis.

Impacto de la fluorosis dental en la calidad de vida de adolescentes ecuatorianos de entre 11 a 14 años / Impact of dental fluorosis over the quality of life of ecuadorian teenagers between 11 and 14 years

Resumen El propósito de este estudio fue determinar el impacto de la fluorosis dental (FD) en la calidad de vida (CV) de adolescentes entre 11 a 14 años del cantón Latacunga, Cotopaxi, Ecuador. Materiales y métodos: Se plantea un estudio descriptivo, en una muestra de 128 adolescentes entre 11 a 14 años y sus respectivos padres, empleando como instrumentos de recolección de información, la encuesta INEN para determinar el nivel socioeconómico, el cuestionario CPQ11-14 para precisar calidad de vida, y un registro fotográfico intraoral de cada adolescente, analizado posteriormente por tres investigadores según el índice de Thylstrup y Fejerskov (TF). Un análisis químico sobre la concentración de flúor en las fuentes de abastecimiento de agua de consumo, fue ejecutado complementariamente. Resultados: La prevalencia de FD fue de 70,3% en los grados TF 1, 2,3. El análisis químico del agua mostró una media de flúor de 1,06 mg/l. Las pruebas estadísticas revelaron una relación de la CV con FD (p = 0,000) y con el nivel socioeconómico (p = 0,001). Conclusiones: La CV se ve afectada con la presencia de FD y el nivel socioeconómico, sin relación con la edad, sexo o la presencia de flúor en el agua de consumo.

Abstract The purpose of this study was to determine the impact of dental fluorosis (DF) over the quality of life (QoL) of adolescents between 11 and 14 years old, of Latacunga, Cotopaxi, Ecuador. Materials and methods: This descriptive study had a sample of 128 adolescents between 11 to 14 years old and their respective parents. The information was collected through, the INEN survey to determine socioeconomic status and the CPQ11-14 survey to determine adolescents' QoL. In addition, intraoral photographic records were obtained for DF detection according Thylstrup and Fejerskov index (TF) and the public water company accomplished chemical analysis of fluoride concentration in water sources. Results: The prevalence of DF was 70.3% corresponding to TF 1, 2, 3 index. Chemical analyzes of water showed an average of 1.06 mg / l on Fluoride levels. Statistical analysis showed correlation between QoL and Fluorosis presence (p = 0.000) and QoL to socio-economic level (p = 0.001). Conclusions: QoL relates to DF and the socio-economic level. However, it is not to age, sex or fluoride levels in consumption water. Key words: Teenagers, dental fluorosis, oral health, life quality, water fluoridation, epidemiology, dental health survey, public health dentistry.

[Etiology, diagnosis, prevention and treatment of dental fluorosis].

Dental fluorosis is the most common and prominent symptom in the early stage of chronic fluorosis, which is caused by excessive fluorine intake during tooth development. In severe cases, it may be accompanied by skeletal fluorosis. There are also systemic damages to the nervous system, cardiovascular system, endocrine system and so on. The pathogenesis of dental fluorosis is not totally clear, which may be a complex pathological process involving both genetic and environmental factors. The prevalence of dental fluorosis has an upward trend arround the world, thus certain public prevention and treatment strategies need to be taken. This article focuses on the prevalence, etiology, diagnosis and scoring system, as well as the public prevention and treatment strategies, of dental fluorosis, so that to provide reference for the research and prevention of the disease.

La exposición prenatal a fluoruro induce cambios en la porción coronal de la cripta ósea y altera la erupción dental en crías lactantes / Prenatal fluoride exposure induces changes in the coronal portion of bony crypt and alters dental eruption in suckling rats

La erupción dental es un proceso estrictamente regulado y programado espacial y temporalmente. El objetivo del trabajo fue estudiar el efecto de la exposición prenatal a fluoruro de sodio (NaF) sobre los eventos morfológicos y celulares que ocurren en el hueso supracoronal del primer molar de crías de rata durante la etapa preeruptiva. Se emplearon crías (n=6-8 por grupo) provenientes de madres que bebieron crónicamente agua con diferentes concentraciones de F- en forma de NaF durante la gestación y lactancia: control y NaF (50 mg/L). En cortes histológicos de la mandíbula de crías de 3 y 10 días se analizaron parámetros de histomorfometría estática en la zona supracoronal de la canastilla ósea a la altura del primer molar inferior: volumen óseo trabecular [BV/TV (%)], número de osteoclastos por milímetro (N.Oc/mm) y las variables indirectas: número de trabéculas [Tb.N (1/mm)], espesor [Tb.Th (µm)] y separación trabecular [Tb.Sp (µm)]. En crías de 15 días se midió el grado de erupción [TED (µm)] del primer molar inferior. Los resultados se analizaron con el test "t" de Student considerando diferencias significativas a p<0,05. El análisis histomorfométrico demostró un incremento en el BV/TV (%) del hueso supracoronal (p<0,01) asociado con disminución del N.Oc/mm (p<0,01) en crías de 3 y 10 días expuestas prenatalmente al F-. El grado de erupción dental fue menor en animales expuestos prenatalmente al F- en comparación con los controles (p<0,01). En conclusión, los resultados observados en la mandíbula de crías expuestas durante la etapa prenatal y posnatal temprana al F- sugieren un efecto disruptivo sobre la actividad resortiva necesaria para formación del canal eruptivo. (AU)

Tooth eruption is a tightly regulated and spatially and temporally programmed process. The aim of this study was to examine the effect of prenatal NaF exposure on the morphological and cellular events that occur in the supracoronal area of bony crypt of the first rat molar during the preeruptive stage. Offspring from two groups of rats were used (6-8 per group): Control and 50 mg/L NaF. The treatment was performed during pregnancy and lactation. Suckling pups were euthanized at 3-, 10- and 15-days-old by cervical dislocation. Mandibles were removed and histologically processed to obtain buccolingual sections stained with H&E. In sections of first mandibular molar of 3- and 10-days-old pups, the following static histomorphometric parameters were evaluated: trabecular bone volume [BV/TV (%)] and number of osteoclasts (N.Oc/mm). Also, indirect parameters were obtained: trabecular number [Tb.N (1/mm)], trabecular thickness [Tb.Th (µm)], and trabecular separation [Tb.Sp (µm)]. The degree of tooth eruption [TED (µm)] was determined. Results are expressed as mean ± SE and analyzed by Student t-test. Histomorphometric analysis showed an increase in the BV/TV (%) of the bone crypt of 3- and 10- days-old pups exposed to NaF (p <0.01); this increase was associated with a decrease in the N.Oc/mm (p <0.01). TED of mandibular first molar was lower in prenatal NaF exposed group than in control group (p<0.01). In conclusion, the increased BV/TV and the lower N.Oc observed in the bone crypt of 3- and 10- days-old pups from mothers treated with NaF suggested a disruptive effect triggered by F- on the formation events of the eruptive pathway in the offspring. (AU)

Translating from lab-use to household: Dual-functional upconversion nanoprobes for solar-powered photothermal fluorosis diagnosis.

Due to the serious symptoms of brittle bones and endocrine disorders, the common disease fluorosis diminishes quality of life. With the aim of developing probes for both laboratory and household fluorosis diagnosis, in this study we rationally designed a novel dual-functional gallic acid-Fe(III) complex-modified upconversion nanoprobe (DF-UCNP) with simultaneous upconversion luminescence (UCL) and photothermal (PT) conversion capacities. The nanoprobe was feasible for UCL fluorine (F-) detection with a low detection limit of ∼20 nM and a broad linear range of 0-50 µM, as well as UCL fluorosis diagnosis both in vitro and in vivo for lab-use. Furthermore, by utilizing gathered solar irradiation as a PT excitation source and a digital thermometer as a signal reader, the nanoprobe possessed outstanding PT detection capacities for F- with a detection limit of ∼100 nM. Based on this nanoprobe and an accessional self-developed Android application, a household PT kit for fluorosis diagnosis was also constructed. This work provides a new method for rapid laboratory fluorosis diagnosis without a cumbersome determination process as well as household fluorosis diagnosis without requiring specific instruments.

[Differential diagnosis of dental enamel focal demineralization and fluorosis by means of spectrophotometry]. / Differentsial'naia diagnostika ochagovoi demineralizatsii émali zubov i fliuoroza s pomoshch'iu spektrofotometricheskogo metoda.

The article presents the results of spectrophotometric tooth enamel scanning for differential diagnosis of focal enamel demineralization and fluorosis. Research was conducted in vivo on teeth affected by these diseases. VITA EasyShade spectrophotometer measurements were made on the affected area and on the visually healthy part of enamel. The lightness appeared as the only one differential significant optical characteristics of tooth enamel. Lightness metrics were higher in the case of initial caries than on the healthy part of enamel when these metrics were lower in the case of fluorosis than on the healthy part of enamel.

In vitro Validation of Quantitative Light-Induced Fluorescence for the Diagnosis of Enamel Fluorosis in Permanent Teeth.

This study aimed to validate quantitative light-induced fluorescence (QLF) as a diagnostic tool for mild and moderate enamel fluorosis in permanent teeth, comparing it to visual diagnosis and histological assessment completed using polarized light microscopy (PLM). The buccal surfaces of 139 teeth were visually classified using the Thylstrup and Fejerskov Index (TFI) into sound (TFI 0; n = 17), mild (TFI 1-2; n = 69), and moderate (TFI 3-4; n = 43) fluorosis. Fluorosis was then assessed with QLF (variables ΔF, A, and ΔQ at 5-, 15-, and 30-radiance thresholds) using as reference areas the entire surface and a region of interest (ROI), identified as the most representative region of a fluorosis lesion. PLM images of longitudinal thin sections including the ROI were assessed for histological changes. Correlations among TFI, PLM, and QLF were determined. A receiver-operating characteristic curve was conducted to determine QLF's diagnostic accuracy when compared to the TFI and PLM assessments. This was used to assess the probability that the images were correctly ranked according to severity as determined by PLM and TFI. A positive correlation was found between QLF and PLM, and between QLF and TFI. QLF showed the highest sensitivity and specificity for the diagnosis of mild fluorosis. There was also a strong agreement between TFI and PLM. The selection of a ROI resulted in a stronger correlation with TFI and PLM than when the entire surface was used. The study results indicate that defining an ROI for QLF assessments is a valid method for the diagnosis of mild and moderate enamel fluorosis.