Association between genetic variants in key vitamin-D-pathway genes and external apical root resorption linked to orthodontic treatment.

This study evaluated the association between single-nucleotide polymorphisms (SNPs) in vitamin-D-related genes and the amount of external apical root resorption linked to orthodontic treatment. One hundred and forty-three individuals were assessed. The amount of external apical root resorption of upper central incisors (EARRinc ) and lower first molars (EARRmol ) were evaluated in radiographs. Seven SNPs were genotyped across four genes including the vitamin D receptor [VDR], group-specific component [GC], cytochrome P450 family 27 subfamily B member 1 [CYP27B1], and cytochrome P450 family 24 subfamily A member 1 [CYP24A1]. Linear regressions were implemented to determine allele-effects on external apical root resorption. Individuals carrying the AA genotype in VDR rs2228570 had a 21% higher EARRmol than those having AG and GG genotypes (95% CI: 1.03,1.40). EARRmol in heterozygous rs2228570, was 12% lower than for homozygotes (95%CI: 0.78,0.99). Participants with the CCG haplotype (rs1544410-rs7975232-rs731236) in VDR had an EARRmol 16% lower than those who did not carry this haplotype. Regarding CYP27B1 rs4646536, EARRinc in participants who had at least one G allele was 42% lower than for homozygotes AA (95%CI: 0.37,0.93). Although these results did not remain significant after multiple testing adjustment, potential associations may still be suggested. Further replication studies are needed to confirm or refute these findings.

Worldwide trends on molar incisor and deciduous molar hypomineralisation research: a bibliometric analysis over a 19-year period.

AIM: To identify the worldwide trends in scientific evidence and gaps in knowledge regarding molar incisor hypomineralisation (MIH) and deciduous molar hypomineralisation/hypomineralised second primary molars (DMH/HSPM), exploring the contribution of authors and countries, possible etiological factors and proposed treatments, in order to guide future research in the area. METHODS: Searches were conducted in MEDLINE, Scopus, Web of Science, Cochrane Library, Lilacs/BBO, Embase and Google Scholar. Studies employing the terms MIH, DMH/HSPM and their linguistic variations were included. The following data were extracted: title, authors, year and journal of publication and first author's affiliation country. Studies were categorized according to topic, dentition, study design, etiological factors and types of treatments. Categories were analysed in relation to their distribution, co-occurrence, cross-correlation and/or autocorrelation. RESULTS: Five hundred and three studies were included. The most published authors were Manton D (n = 47), de Souza JF (n = 22) and Ghanim A (n = 22) and four main collaboration clusters have been identified. Most of the studies were conducted on permanent dentition (MIH) (87.4%); with observational design (57.2%). The "European Archives of Paediatric Dentistry" was the most published journal (13.3%) and a significant increase in the number of publications was observed in the last decade. MIH was most studied in relation to prevalence/incidence, systemic factors involved in its aetiology and treatment with composite restorations, while a gap in knowledge was observed for extraction and sealants. Less studies were published on DMH/HSPM and most of them evaluated risk factors or prevalence/incidence. The gap of knowledge was observed in relation to treatments and patient's quality of life. CONCLUSIONS: This bibliometric review provided a comprehensive overview of research in MIH and DMH/HSPM over the past 19 years. Within the limitations of the present study, the following conclusions can be drawn: global trends point to an increasing peak of scientific publication, especially in the last decade, while there is a shortage of clinical studies on treatments, mainly evaluating tooth extractions. Finally the multifactorial nature should be further explored, considering environmental and systemic factors together.