Association of defects of enamel with polymorphisms in the vitamin D receptor and parathyroid hormone genes

Abstract This cross-sectional study aimed to investigate the association between developmental defects of enamel (DDE) and single nucleotide polymorphisms (SNPs) in the genes encoding the vitamin D receptor (VDR) and parathyroid hormone (PTH). Orthodontic patients receiving treatment at a dental school were selected through convenience sampling. Intra-oral photographs were used to assess DDE, which were classified according to the criteria proposed by Ghanim et al. (2015) by a single calibrated examiner (Kappa>0.80). Enamel hypoplasia, molar-incisor hypomineralization (MIH), hypomimineralized second primary molar (HSPM), and non-MIH/HSPM demarcated opacities were considered for the analysis. Genomic DNA was extracted from buccal cells. The SNPs in VDR (rs7975232) and PHT (rs694, rs6256, and rs307247) were genotyped using real-time polymerase chain reactions (PCR). Statistical analyses were performed using the PLINK software (version 1.03, designed by Shaun Purcell, EUA). Chi-square or Fisher's exact tests were performed at a significance level of 5%. Ninety-one (n=91) patients (49 females and 42 males) (mean age of 14.1±5.8 years) were included. The frequency of DDE was 38.5% (35 patients). Genotype distributions were in Hardy-Weinberg equilibrium. No significant statistical association was found between DDE and the SNPs evaluated. A borderline association (p=0.09) was observed between DDE and the CC haplotype for SNP rs7975232 in VDR. In conclusion, the selected SNPs in VDR and PTH genes were not associated with DDE in the studied samples.

Resumo Este estudo transversal teve como objetivo investigar a associação entre defeitos de desenvolvimento do esmalte (DDE) e polimorfismos de nucleotídeo único (SNPs) nos genes que codificam o receptor da vitamina D (VDR) e o hormônio da paratireoide (PTH). Pacientes ortodônticos em tratamento em uma escola Odontologia foram selecionados por amostragem de conveniência. Os DDEs foram avaliados e classificados por um examinador calibrado (Kappa>0,80) através de fotografias intraorais de acordo com os critérios propostos por Ghanim et al. (2015). Os tipos de DDE considerados para análise foram: hipoplasia de esmalte, hipomineralização molar-incisivo (HMI), hipomineralização de segundos molares decíduos (HSMD) e opacidades demarcadas não-HMI/HSMD. O DNA gnômico foi extraído de células bucais. Os SNPs em VDR (rs7975232) e PTH (rs694, rs6256 e rs307247) foram genotipados por PCR em tempo real. As análises estatísticas foram realizadas utilizando o software PLINK (versão 1.03, concebido por Shaun Purcell, EUA). Foram feitos teste de qui-quadrado e teste exato de Fisher com um nível de significância de 5%. Foram incluídos noventa e um (n=91) pacientes (49 do sexo feminino e 42 do sexo masculino) (idade média de 14,1±5,8 anos). A frequência de DDE foi de 38,5% (35 pacientes). As distribuições genotípicas estavam em equilíbrio de Hardy-Weinberg. Não foi encontrada associação estatisticamente significante entre os DDEs e os SNPs avaliados. Foi observada uma associação limítrofe (p=0,09) entre a DDE e o haplótipo CC para o SNP rs7975232 no VDR. Em conclusão, os SNPs seleccionados nos genes VDR e PTH não foram associados à DDE nas amostras estudadas.

Prevalence of developmental defects of enamel in children and adolescents with asthma: A cross-sectional study.

Aim: The aim of this study was to evaluate the prevalence of developmental defects of enamel in children with asthma and its relation to specific characteristics of disease such as symptom onset, asthma severity and treatment initiation in pediatric asthma patients. Materials and Methods: Children and adolescents (104 asthma patients and 104 control subjects), 7-14 years of age and residents of the city of Chennai were enrolled in the study. Medical and dental histories were obtained through the use of structured questionnaire. Each participant underwent a dental examination in which the examiner applied the modified developmental defect index. Results: The prevalence of DDE in this study was as follows: of the 104 asthma group subjects, 80 (76.9%) presented with dental enamel defects, compared with only 28 (26.9%) of those in the control group. Using multivariate logistic regression analysis, the estimated risk of DDE in permanent dentition was 12 times higher in pediatric subjects with asthma than in those without asthma (OR - 12.526, P = 0.001). The occurrence of dental enamel defects correlated with greater asthma severity (P = 0.001) and earlier symptom onset (P = 0.001). However, dental enamel defects did not correlate with the timing of the initiation of treatment (P = 0.041). Conclusion: Pediatric asthma patients with severe, early onset asthma are at increased risk of dental enamel defects and therefore require priority dental care.

Prevalencia de fluorosis dental, opacidades e hipoplasia del esmalte en niños en edad escolar / Prevalence of dental fluorosis, opacities and enamel hypoplasia in schoolchildren

Determinar la frecuencia de fluorosis dental y anomalías en el desarrollo del esmalte: opacidades e hipoplasia del esmalte, en niños en edad escolar entre 6 y 14 años de la Escuela Básica "Fray Juan Ramos de Lora", del estado Mérida, Venezuela. Se realizó un estudio descriptivo transversal. La población estuvo constituida por 92 niños entre 6 y 14 años de edad, de la Escuela Básica "Fray Juan Ramos de Lora", del estado Mérida, Venezuela. Se tomaron en cuenta las variables fluorosis dental, opacidades e hipoplasia del esmalte, aplicando los índices según la metodología descrita por la Organización Mundial de la Salud (OMS) y la Encuesta Básica de Salud Bucodental. El 75% de los participantes no presentaron fluorosis dental, en contraste con un 1,1% que presentó fluorosis severa. El 70,7% de la población no presentó anomalías en el desarrollo del esmalte, en contraste con un 16,3% y 13,1% que presentó opacidades delimitadas y difusas respectivamente. Se evidencia que el mayor porcentaje de la población estudiada no presenta fluorosis dental ni alteraciones en el desarrollo del esmalte

To determine the frequency of dental fluorosis and developmental defects of enamel: opacities and hypoplasia in 6-14-year-old-school children from the Basic School "Fray Juan Ramos de Lora" in Mérida, Venezuela. This was a cross-sectional descriptive study. The population was constituted by 92 6-14-year-old-school children from the Basic School "Fray Juan Ramos de Lora" in Mérida, Venezuela. The variables dental fluorosis, opacities and enamel hypoplasia were taken into account by using the indexes according to the methodology described by the World Health Organization (WHO) and the Basic Survey of Dental Health. Results indicated that 75% of the participants did not show dental fluorosis in contrast to 1.1% that presented severe fluorosis. Besides, 70.7% of the population did not present developmental defects of enamel while opposite to 16.3% and 13.1% who presented delimitated and diffuse opacities, respectively. It is evident that the higher percentage of the studied population does not present dental fluorosis or developmental alterations of enamel

Defeitos de desenvolvimento do esmalte em crianças pré-termo e com distúrbios neurológicos / Developmental defects of enamel in children prematurely born and with neurological disorders

Os autores apresentam revisão sobre defeitos de desenvolvimento do esmalte em dentes decíduos e a possibilidade de utilizá-los como marcadores biológicos, funcionando como mais um elemento na elucidação dos eventos neonatais envolvendo a prematuridade e a paralisia cerebral.

The authors present a review about developmental defects of enamel in deciduous teeth, their possible use as biological markers and potential as an additional element to elucidate neonatal events involved in prematurity and cerebral palsy.