Evidence Linking PPARG Genetic Variants with Periodontitis and Type 2 Diabetes Mellitus in a Brazilian Population.

The peroxisome proliferator-activated receptor gamma (PPARG) gene encodes a transcription factor involved in the regulation of complex metabolic and inflammatory diseases. We investigated whether single nucleotide polymorphisms (SNPs) and haplotypes of the PPARG gene could contribute with susceptibility to develop periodontitis alone or together with type 2 diabetes mellitus (T2DM). Moreover, we evaluated the gene-phenotype association by assessing the subjects' biochemical and periodontal parameters, and the expression of PPARG and other immune response-related genes. We examined 345 subjects with a healthy periodontium and without T2DM, 349 subjects with moderate or severe periodontitis but without T2DM, and 202 subjects with moderate or severe periodontitis and T2DM. PPARG SNPs rs12495364, rs1801282, rs1373640, and rs1151999 were investigated. Multiple logistic regressions adjusted for age, sex, and smoking status showed that individuals carrying rs1151999-GG had a 64% lower chance of developing periodontitis together with T2DM. The CCGT haplotype increased the risk of developing periodontitis together with T2DM. The rs1151999-GG and rs12495364-TC were associated with reduced risk of obesity, periodontitis, elevated triglycerides, and elevated glycated hemoglobin, but there was no association with gene expression. Polymorphisms of the PPARG gene were associated with developing periodontitis together with T2DM, and with obesity, lipid, glycemic, and periodontal characteristics.

Bruxism Throughout the Lifespan and Variants in MMP2, MMP9 and COMT.

Bruxism is a masticatory muscle activity characterized by grinding of the teeth and clenching of the jaw that causes tooth wear and breakage, temporomandibular joint disorders, muscle pain, and headache. Bruxism occurs in both adults and children. Clinical characteristics and habits were evaluated in an adult sample. Moreover, we used DNA samples from 349 adults and 151 children to determine the presence of association with specific genes. Genomic DNA was obtained from saliva. The markers rs2241145 and rs243832 (metalloproteinase 2 (MMP2)), rs13925 and rs2236416 (metalloproteinase 9 (MMP9)), and rs6269 (cathecol-o-methyltransferase (COMT)) were genotyped. Data were submitted to statistical analysis with a significance level of 0.05. In adults, in univariate logistic regression, presence of caries, attrition, and use of alcohol were increased in bruxism individuals (p < 0.05). In addition, in adults, there was an association between bruxism and MMP9 (rs13925, p = 0.0001) and bruxism and COMT (rs6269, p = 0.003). In children, a borderline association was observed for MMP9 (rs2236416, p = 0.08). When we performed multivariate logistic regression analyses in adults, the same clinical characteristics remained associated with bruxism, and orthodontic treatment was also associated, besides rs13925, in the AG genotype (p = 0.015, ORa: 3.40 (1.27-9.07)). For the first time, we provide statistical evidence that these genes are associate with bruxism.

Prenatal exposure to gestational diabetes mellitus increases developmental defects in the enamel of offspring.

BACKGROUND AND OBJECTIVE: Gestational diabetes mellitus (GDM) is associated with short- and long-term maternal and perinatal repercussions. Our objective was to evaluate the long-term consequences of intrauterine exposure to hyperglycemia on Developmental Defects of Enamel (DDE) in offspring. RESULTS: Overall, 50 children of women with GDM and 250 children of normoglycemic women participated, the latter serving as controls. Children were examined at the age between 3 and 12 years. In addition to physical examination, two independent observers examined and rated photographs to identify specific types of DDE in a blinded fashion. Among offspring of mothers with GDM, rates of DDE (all types combined) and hypoplasia (specific type) were significantly higher (p<0.001, p = 0.04), in comparison to offspring of normoglycemic mothers. Considering only the affected teeth (1060 in GDM category; 5499 in controls), rates of DDE (all types combined) were significantly higher for total teeth (p <0.001) and deciduous teeth (p<0.001), but not permanent teeth. In specific types of DDE involving deciduous teeth, rates of demarcate opacity were significantly higher (p<0.001; canine and 2nd mandibular molars) and hypoplasia (p <0.001; 2nd maxillary molars and 2nd mandibular molars). In permanent teeth, the rate of diffuse opacity in association with GDM was significantly higher (p<0.001; maxillary central incisors and 1st maxillary molars). CONCLUSION: GDM was associated with the adverse effects of DDE on offspring. This study lays the foundation for future studies to determine the impact of GDM on long-term risk of DDE.

Are mTOR and Endoplasmic Reticulum Stress Pathway Genes Associated with Oral and Bone Diseases?

The purpose of this cohort study was to identify associations between combined oral and bone disease phenotypes and genes present in cell regulatory pathways. The studied pathways play important roles in cellular growth, proliferation, differentiation, and homeostasis. DNA samples extracted from whole saliva of 3,912 individuals were genotyped and these data analyzed according to dental caries experience, periapical lesions, periodontitis, osteoporosis, or temporomandibular joint discomfort. Samples were obtained from the Dental Registry and DNA Repository project at the University of Pittsburgh. Twenty-seven polymorphisms in eight genes related to mTOR or endoplasmic reticulum stress pathways were selected for genotyping. Allele frequencies and Hardy-Weinberg equilibrium were calculated. Analyses were performed comparing genotypes between affected and unaffected individuals for each phenotype, as well as for the associated phenotypes combined. For all analyses, we used the software PLINK with an alpha of 0.002. Borderline associations with multiple variants of several genes were found, suggesting that both pathways may be involved in the susceptibility to multiple conditions affecting the oral cavity and bones. When combining patients that had concomitant dental caries, periodontitis, and periapical pathology, several markers in RHEB showed statistically significant association. Multiple conditions affecting bone and teeth (i.e., dental caries, periodontitis, periapical lesion formation, and osteoporosis) appear to share similar underlying genetic etiological factors, which allow us to hypothesize that instead of individually, they should be studied in conjunction in human populations.

Fine-Mapping of Xq25.1-27.2 Shows Association of Early Childhood Caries with Genetic Variants Depending on Dietary Habits, Protecting Children Who Drink Milk before Going to Bed.

Early childhood caries (ECC) is a chronic, infectious disease that affects the primary dentition of young children. It is the result of unequal contributions of risk factors and protective factors that influence the disease. The aim of this study was to assess if the X chromosome region previously linked to caries was associated with ECC. Two hundred and fifty-nine unrelated children with no chronic illnesses from 2 to 5 years of age who had no systemic fluoride consumption were evaluated using a cross-sectional design. Data on oral habits were obtained through a questionnaire, and caries experience data were collected by clinical examination. Twenty-three markers in ten genes were studied. Genotyping of the selected polymorphisms was carried out by real-time polymerase chain reaction. Regression analyses were performed comparing individuals with and without caries experience. Of 259 subjects, 123 were caries free. The markers in Xq25.1-27.2 were associated with ECC when children were using milk bottle for longer times (p = 0.01) and had more snacks over the course of a day (p = 0.05). Conversely, the markers in the X chromosome studied here were protective for ECC (p = 0.008) in children consuming milk before going to sleep. The genes located in the X chromosome possibly contribute to ECC and have an impact on ECC depending on the dietary habits.

Family-Based Genetic Association for Molar-Incisor Hypomineralization.

Despite some evidence of genetic and environmental factors on molar-incisor hypomineralization (MIH), its aetiology remains unclear. This family-based genetic association study aimed more comprehensively to investigate the genetic carriage potentially involved in MIH development. DNA was obtained from buccal cells of 391 individuals who were birth family members of 101 Brazilian nuclear families. Sixty-three single nucleotide polymorphisms (SNPs) were investigated in 21 candidate genes related to amelogenesis using the TaqMan™ OpenArray™ Genotyping platform. All SNPs were genotyped in 165 birth family members unaffected by MIH, 96 with unknown MIH status and 130 affected individuals (50.7% with severe MIH). Association analysis was performed by the transmission/disequilibrium test (TDT), and statistical results were corrected using the false discovery rate. Significant results were obtained for SNPs rs7821494 (FAM83H gene, OR = 3.7; 95% CI = 1.75-7.78), rs34367704 (AMBN gene, OR = 2.7; 95% CI = 1.16-6.58), rs3789334 (BMP2 gene, OR = 2.9; 95% CI = 1.34-6.35), rs6099486 (BMP7 gene, OR = 2.2; 95% CI = 1.14-4.38), rs762642 (BMP4 gene, OR = 2.3; 95% CI = 1.38-3.65), rs7664896 (ENAM gene, OR = 2.1; 95% CI = 1.19-3.51), rs1711399 (MMP20 gene, OR = 0.4; 95% CI = 0.20-0.72), rs1711423 (MMP20 gene, OR = 2.1; 95% CI = 1.18-3.61), rs2278163 (DLX3 gene, OR = 2.8; 95% CI = 1.26-6.41), rs6996321 (FGFR1 gene, OR = 2.7; 95% CI = 1.20-5.88), and rs5979395 (AMELX gene, OR = 11.7; 95% CI = 1.63-84.74). Through this family-based association study, we concluded that variations in genes related to amelogenesis were associated with the susceptibility to develop MIH. This result is in agreement with the multifactorial idea of the MIH aetiology, but further studies are necessary to investigate more thoroughly the factors that could influence MIH.

Control of white spot lesion adjacent to orthodontic bracket with use of fluoride varnish or chlorhexidine gel.

The aims of this study were to compare the effectiveness of fluoride varnish and chlorhexidine gel in controlling white spot lesions (WSLs) adjacent to orthodontic brackets and to compare the ability of Quantitative Light-Induced Fluorescence (QLF) to measure mineral uptake with that of transverse microradiography (TMR). Thirty premolars with artificially induced WSLs were randomly assigned to three groups: (1) two applications of 5% NaF-varnish (F), with one-week interval, (2) two applications of 2% chlorhexidine gel (CHX), with one-week interval, and (3) control (CO), no treatment. QLF was used to measure changes in fluorescence before and after caries induction, 1 week after each application and 1, 2, and 3 months after the last application of F or CHX. TMR was performed to quantify lesion depth and mineral content after caries induction to evaluate the effects of F, CHX, and CO 3 months after the last application of agents. The data were analyzed by repeated measures ANOVA and Tukey's test. All treatments increased the mineral content during the experimental period; however, F induced faster remineralization than CHX. The correlation between QLF and TMR was significantly moderate. Two applications of fluoride varnish or 2% chlorhexidine gel at one-week intervals were effective in controlling WSLs.

Influence of sterilization process on cutting effectiveness andurability of ultrasonic tips / Influência do processo de esterilização na efetividade de corte e durabilidade das pontas ultra-sônicas

Objetivo: O objetivo foi avaliar a influência de diferentes métodos de esterilização na efetividade de corte e durabilidade de pontas ultra-sônicas cilíndricas comparadas com pontas diamantadas cilíndricas convencionais. Material e Métodos:Quinze pontas diamantadas cilindricas (1092)(KG Sorensen) acopladas a um motor de de alta rotação, e quinze pontas ultrassonicas cilíndricas(8,2137) (CVDentus) acopladas a um ultra-som foram utilizadas para realizar preparos cavitários padronizados em fragmentos de dentes bovinos higidos, limpos com taça de borracha, pedra-pomes e água. Após cada um dos 10 preparos, as pontas foram9 vezes esterilizadas em autoclave (SA), estufa (SO), ou limpas com escova, sabão e água (C). Os fragmentos foram pesados e microfotografias das pontas foram tomadas no início e no final do experimento. Outras9 pontas de diamante CVD e 9 convencionais foram submetidos aos mesmos ciclos de esterilização em autoclave (SAC), forno (SOC) ou lavado com água e sabão (CC) no entanto, sem serem usadas para fazer preparos cavitários, servindo como controle. Realizou-se análise descritiva dos valores encontrados na pesagem e dos scores das microfotografias.Resultados: Diferenças estatisticamente significativas(teste t de Student pareado) foram observadas entre as pontas após a esterilização (p = 0,0001). SOe SA não influenciaram na efetividade de corte e durabilidade das pontas diamantadas ultra-sônicas e convencionais. As microfotografias mostraram diferenças morfológicas entre as pontas utilizadas para os preparos e o controle. Conclusão: As esterilizaçoes por autoclave e estufa não influenciaram a efetividade de corte e durabilidade das pontas diamantadas convencionais. Pontas diamantadas convencionais apresentaram maiores alterações estruturais após a realização de preparos cavitários e procedimentos de limpeza / esterilização, independentemente do processo utilizado.

Objectives: The aim was to evaluate influence of different sterilization methods on cutting effectiveness and durability of cylindrical ultrasonic burs compared with conventional cylindrical diamond-coatedburs. Material and Methods: Fifteen conventional cylindrical diamond-coated (1092) (KG Sorensen) coupled to a high-speed turbine, and fifteen cylindrical ultrasonic (8.2137) (CVDentus) burscoupled to an ultrasound-handpiece were used toper form standardized cavity preparations in healthy bovine tooth fragments, cleaned with rubber cup, pumice stone and water. After every 10 preparations, burs were sterilized 9 times in autoclave (SA), oven (SO), or cleaned with brush, soap and water (C). Fragments were weighed and microphotographs of burs were taken at the beginning and end of experiment. Another 9 conventional diamond-coatedand 9 CVD burs under went the same sterilizationcycles in autoclave (SAC), oven (SOC) or washedwith soap and water (CC) however, without beingused for making cavity preparations, serving ascontrol. Descriptive analyses were made of thevalues found by weighing and microphotographyscores. Results: Statistically significant differences (Paired Student’s-t test) were observed among bursafter sterilization (p = 0.0001). SO and SA didnot influence cutting effectiveness and durability of ultrasonic and conventional diamond-coatedburs. The microphotographs showed morphological differences between the burs used for preparation and the control. Conclusion: Sterilization by oven andautoclave did not influence cutting effectiveness and durability of CVD and conventional diamond-coatedburs. Conventional diamond-coated burs presented greater structural alterations after performing cavity preparations and cleaning/sterilization procedures, irrespective of the process used.