Gene-environment Interactions in the Etiology of Dental Caries

The Effects of MMP3 (rs679620) and VDR (rs731236) Gene Polymorphisms on Dental Caries: A Pilot Study

OBJECTIVE

 Caries formation is a process affected by various factors. Studies have shown that genetic factors also play a role in caries formation. The aim of our study is to examine the effects of matrix metalloproteinase (MMP)3 (rs679620) and vitamin D receptor (VDR) (rs731236) gene polymorphisms on caries formation.

MATERIALS AND METHODS

 Following routine oral examinations in individuals aged between 20 and 44 years, the diagnosis was made according to the decayed, missing, and filled teeth (DMFT) index, and experimental group was defined as "high caries risk" (DMFT ≥ 14, n = 28), and the control group as "no caries" (DMFT = 0, n = 28). Plaque index and bleeding on probing were measured from participants with a detailed anamnesis. Periodontally healthy individuals with less than 10% bleeding on probing were included in the study (n = 56). After DNA isolation from blood samples taken from the participants, the genotyping of MMP3 (rs679620) and VDR (rs731236) gene polymorphisms were determined using the real-time polymerase chain reaction technique.

STATISTICAL ANALYSIS

 Data were analyzed with IBM SPSS V23.0. Data distribution was evaluated with Kolmogorov-Smirnov's test. Pearson's chi-square test was used to compare categorical data according to groups. The results were evaluated using a significance level of p < 0.05.

RESULTS

 Regarding MMP3 and VDR gene polymorphisms, there was a statistically significant difference between the groups in terms of MMP3 (rs679620) (p < 0.001). There was no statistically significant difference between the VDR (rs731236) genotype distributions of the groups (p = 0.659).

CONCLUSION

 Within the limits of this study, MMP3 rs679620 gene polymorphism may have an effect on caries formation.

Genetic variations in exon 10 of ENAM and their association with early childhood caries

OBJECTIVE

Enamelin is the largest enamel matrix protein encoded by the ENAM gene. The primary purpose of this study was to identify genetic variants in ENAM exon 10 that can alter susceptibility to early childhood caries (ECC).

METHODS

This case-control study included 248 children aged 3-6 years, with 124 children diagnosed with ECC in the case group and 124 children without caries in the control group. Questionnaires were used to record demographic data, socioeconomic status, hygienic practices, and feeding practices, and a 24-h diet diary was kept. Seven polymorphisms (rs7671281, rs1738668322, rs3796703, rs3796704, rs759376039, rs775159311, and rs1738678483) in ENAM exon 10 were sequenced.

RESULTS

The heterozygous CT genotype of rs7671281 was significantly more common in the case group compared to the control group (odds ratio [OR], 6.1765; 95% confidence interval [CI], 2.05-18.58; P = 0.0006). Under the dominant model, the TT genotype of rs7671281 was significantly more common in the control group (OR, 6.47; 95% CI, 2.15-19.39; P < 0.001). The AG genotype of rs3796704 was significantly more common in the case group than in the control group (OR, 5.705; 95% CI, 1.60-20.25; P = 0.006). Under the dominant model, the GG genotype of rs3796704 was significantly more common in children without caries than in children with caries (OR, 6.84; 95% CI, 1.96-23.90; P < 0.001).

CONCLUSIONS

The C allele of rs7671281 and the A allele of rs3796704 can increase susceptibility to ECC.

AMELX gene association to early childhood caries in south-Indian children: a case-control study

PURPOSE

Genetic variants of AMELX gene can affect the protein content, organization of enamel prisms, microstructure and microhardness of the enamel, thus altering the caries susceptibility. The present study aims to assess the association between polymorphisms rs17878486, rs5934997, and rs5933871 of AMELX gene and Early Childhood Caries (ECC).

MATERIALS AND METHODS

This case-control study was conducted on 200 participants, aged 3-6 years, with 100 controls and 100 children with ECC. A questionnaire was used to collect demographic data, birth-weight, type of delivery, oral hygiene practices, feeding history and 24-h diet diary. DNA was isolated from blood and subjected to PCR followed by Sanger sequencing.

RESULTS

The CC genotype of rs17878486 showed an OR of 1.93 (0.34-10.81; P = 0.73). In a recessive model, the CC genotype of rs17878486 reported an OR of 2.04 (0.36-11.40; P = 0.68); rs5593871 reported an OR of 1.00 (0.31-3.21). Statistically significant differences (P ≤ 0.05) between genotype and allele frequencies of rs17878486, rs5934997, and rs5933871 were not observed between children with ECC and the controls.

CONCLUSION

Polymorphisms of AMELX gene did not show a significant association with ECC in this population. However, documentation of genetic data in a global context of ECC may be essential for the future.

Generalised Periodontitis: Examining TAS2R16 Serum Levels and Common Gene Polymorphisms (rs860170, rs978739, rs1357949)

The objective of this study was to evaluate and compare the associations between TAS2R16 serum levels and common gene rs860170, rs978739, and rs1357949 polymorphisms in patients affected by generalized periodontitis. The study enrolled 590 patients: 280 patients with periodontitis and 310 healthy controls as a reference group. Patients underwent periodontal examination and radiographic analysis to confirm the periodontitis diagnosis. Blood samples were collected, and the DNA salting-out method was used for DNA extraction from peripheral venous blood. Genotyping of TAS2R16 (rs860170, rs978739, and rs1357949) was performed using real-time polymerase chain reaction (RT-PCR), and serum level analysis was performed for both periodontitis-affected patients and reference group subjects. The analysis of TAS2R16 rs860170 (TT, CT, and CC) showed a statistically significant difference between generalized periodontitis and the reference group (41.8%, 58.2%, and 0% vs. 38.7%, 56.1%, and 5.2%, p < 0.001). TAS2R16 rs860170 (TT, CT, and CC) showed a statistically significant difference between males in generalized periodontitis and reference groups (38.4%, 61.6%, and 0% vs. 32.9%, 56.6%, and 10.5%, p = 0.002). Female-specific analysis showed that the TAS2R16 rs978739 C allele was more frequent in generalized periodontitis compared to the reference group (37.5% vs. 28.7%, p = 0.016). Subjects aged 70 years and older demonstrated a statistically significant difference in TAS2R16 rs860170 (TT, CT, and CC) between generalized periodontitis and the reference group (42.8%, 57.2%, and 0% vs. 38.6%, 53.8%, and 7.6%, p = 0.003). TAS2R16 serum levels were elevated in generalized periodontitis compared to the reference group (0.112 (0.06) ng/mL vs. 0.075 (0.03) ng/mL, p = 0.002). Females carrying the TAS2R16 rs978739 C allele were more prone to generalized periodontitis development. Associations were found between TAS2R16 rs860170 polymorphisms, elevated TAS2R16 serum levels, and generalized periodontitis development.

Association between polymorphisms of immune response genes and early childhood caries - systematic review, gene-based, gene cluster, and meta-analysis

BACKGROUND

Early childhood caries is a significant public health concern affecting about 600 million children globally. The etiology of early childhood caries can be explained as an interplay between genetic and environmental factors. Single nucleotide polymorphisms are the most common variations in the human genome. Genetic variations of immune response genes can modify the defense response of the host, and alter the susceptibility to bacterial colonization of the oral cavity and early childhood caries. The aim of this systematic review is to identify genetic variants of immune response genes associated with early childhood caries.

RESULTS

A total of 7124 articles were identified by conducting an elaborate search across various electronic databases and genome-wide association studies databases. Subsequent to exclusion at various stages, fifteen articles qualified to be included into the present review. Risk of bias assessment was done with the Q-genie tool. Quantitative synthesis revealed that the odds ratio for TT and CC genotypes of rs11362 was 1.07 (0.67-1.71) and 1.16 (0.84-1.60), respectively. Gene-based analysis revealed a statistically significant association between variants of tumor necrosis factor-alpha gene and T-cell receptor alpha variable 4 locus with early childhood caries. Gene clustering showed the presence of three functional clusters. To comprehend the protein-protein interaction, the bioinformatic tool of "Search Tools for the Retrieval of Interacting Genes and Proteins" was used. Among the biological processes and the reactome pathways, complement activation through the lectin pathway showed the highest strength of association with early childhood caries. To understand the interaction and functionality of the genes, "gene function prediction using Multiple Association Network Integration Algorithm" was used, which revealed that the genes were linked by physical interaction (39.34%) and through co-expression (34.88%).

CONCLUSIONS

Genotype TT of rs7217186 of arachidonate 15-lipoxygenase gene was a risk factor for early childhood caries. Multiple genetic variants of T-cell receptor alpha variable 4 locus and tumor necrosis factor-alpha gene were associated with increased susceptibility to early childhood caries. Polymorphisms of genes regulating the lectin pathway of complement activation can modify the susceptibility to early childhood caries.

Multiomics analysis reveals the genetic and metabolic characteristics associated with the low prevalence of dental caries

Background

Despite poor oral hygiene, the Baiku Yao (BKY) ethnic group in China presents a low prevalence of dental caries, which may be related to genetic susceptibility. Due to strict intra-ethnic marriage rule, this ethnic has an advantage in studying the interaction between genetic factors and other regulatory factors related to dental caries.

Methods

Peripheral blood from a caries-free adult male was used for whole genome sequencing, and the BKY assembled genome was compared to the Han Chinese genome. Oral saliva samples were collected from 51 subjects for metabolomic and metagenomic analysis. Multiomics data were integrated for combined analysis using bioinformatics approaches.

Results

Comparative genomic analysis revealed the presence of structural variations in several genes associated with dental caries. Metabolomic and metagenomic sequencing demonstrated the caries-free group had significantly higher concentration of antimicrobials and higher abundance of core oral health-related microbiota. The functional analysis indicated that cationic antimicrobial peptide resistance and the lipopolysaccharide biosynthesis pathway were enriched in the caries-free group.

Conclusions

Our study provided new insights into the specific regulatory mechanisms that contribute to the low prevalence of dental caries in the specific population and may provide new evidence for the genetic diagnosis and control of dental caries.

The association between MMP-13 rs478927 gene polymorphism and dental caries susceptibility in children with mixed dentition from Birjand, Iran: A case-control study

Background and Aims

Gene polymorphisms are responsible for at least part of the variation in caries susceptibility despite similar environmental factors. Genes involved in enamel formation like matrix metalloproteinase-13 (MMP-13) may participate in caries process. The aim was to investigate the association between MMP-13 rs478927 polymorphism and caries susceptibility in 6-years-old children from Birjand, Iran.

Methods

Six-years old children from Birjand, Iran, participated in this study. The total decayed, missing, and filled teeth were calculated and defined as caries index (CI). Based on this CI, two groups of high-caries (case) and low-caries (control) were taken into account. Saliva samples were collected and DNA was extracted. The allele and genotypes of MMP-13 rs478927 polymorphism were determined by tetra-primer amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) method. p Value was significant if p < 0.05.

Results

Three hundred sixty-seven children consisted of 186 low-caries children and 181 high-caries children were included in this study. The mean CI was 6.02 ± 0.81. There was no significant association between high and low-caries groups based on socioeconomic status, eating sweet snacks, parents' susceptibility to dental caries, duration of breastfeeding, and the brushing habit (p > 0.05). There wasn't any significant association between genotype distribution of MMP-13 rs478927 polymorphism and CI groups (p = 0.924). This polymorphism was associated with increased caries susceptibility under all genetic models but this effect was not significant (p > 0.05).

Conclusion

The MMP-13 rs478927 gene polymorphism was not significantly associated with dental caries susceptibility in Birjandi children with mixed dentition. It is recommended to conduct studies on children of different dentitions to better understand the role of this polymorphism on caries susceptibility in primary and permanent teeth of children.

Association between Malnutrition and Dental Caries in Iraqi Kurdish Children

BACKGROUND

This paper aimed to study the association of serum Vitamin D level and Body Mass Index (BMI) as representatives of malnutrition at micro and macro levels, respectively, on dental caries.

METHOD AND PARTICIPANTS

A total of 333 randomly selected children aged 6-12 years in Sulaimani, Kurdistan, Iraq were examined for three variables of the Decayed Missed Filled Tooth (DMFT) index, BMI, and Vitamin D serum levels in a single-time cross-sectional snapshot.

RESULTS

The majority of the population studied (70%) were Vitamin D deficient. In the linear regression analysis, both Vitamin D and BMI had insignificant effects on DMFT, with p-values of 0.22 and 0.55, respectively. After the categorization of the data, the risk estimate between normal (≥20 ng/mL) and deficient (<20 ng/mL) Vitamin D groups with regards to the caries and caries-free categories was 1.97 (95% CI: 0.91-4.24). According to the mean and median of the DMFT, which were both 4, the sample is categorized into the low-caries group (DMFT < 4) and high-caries group (DMFT > 4). When these groups are compared to Vitamin D levels and taking 20 and 15 as thresholds, the odds ratios were 1.19 (CI: 0.74-1.92) and 1.88 (CI: 1.20-2.94), respectively. Regarding the BMI, a normal BMI increases the chances of having a lower caries index (OR = 1.83, CI: 1.10-3.03).

CONCLUSIONS

Our results show that having a serum Vitamin D level ≥15 ng/mL and having a normal BMI are associated with a lower caries index in children.

Impact of tooth mineral tissues genes on dental caries: a birth-cohort study

OBJECTIVE

We aimed to investigate whether Single Nucleotide Polymorphisms present in the genes of tooth mineral tissues influence dental caries trajectory across the life course, and if there is an epistatic (gene-gene) interaction between these SNPs.

METHODS

A representative sample of all 5,914 births from the 1982 Pelotas birth cohort study was prospectively investigated. Dental caries trajectory across the life course was assessed at 15(n=888), 24(n=720), and 31 years old(n=539). Group-based trajectory modelling was used to identify distinct subgroups of individuals whose caries measurements followed a similar pattern over time. Genetic material was collected, and individuals were genotyped [rs4970957(TUFT1), rs1711437(MMP20), rs1784418(MMP20), rs2252070(MMP13), rs243847(MMP2), rs2303466(DLX3), rs11656951(DLX3), rs7501477(TIMP2), rs388286(BMP7), and rs5997096(TFIP11)]. Analyzes were performed for allele and genotype using logistic regression and generalized multifactor dimensionality reduction for epistatic interactions.

RESULTS

The analyses included 678 individuals, those with allele C (OR=0.74, CI95%[0.59-0.92]), genotype CC in the additive effect (OR=0.52, CI95%[0.31-0.89]), and the genotype TC/CC in dominant effect (OR=0.72, CI95%[0.53-0.98]) on the rs243847(MMP2) were associated with low caries trajectory. Individuals with the allele T (OR=0.79, CI95%[0.64-0.98]) and the genotype TC/CC in dominant effect (OR=0.66, CI95%[0.47-0.95]) on the rs5997096(TFIP11) were associated with low caries trajectory. Positive epistatic interactions were observed involving two (MMP2 and BMP7; p=0.006) and three (TUFT1, MMP2, and TFIP11; p<0.001) loci and high caries trajectory.

CONCLUSIONS

Some SNPs present in the genes of tooth mineral tissues were associated with caries trajectory and epistatic interactions increasing the network of SNPs involved in individual caries experience.

CLINICAL SIGNIFICANCE

Single nucleotide polymorphisms in the pathway of tooth mineral tissues genes may contribute significantly to the individual caries experience across the life course.

Genome-Wide Analysis of Dental Caries Variability Reveals Genotype-by-Environment Interactions

Genotype-by-environment interactions (GEI) may influence dental caries, although their effects are difficult to detect. Variance quantitative trait loci (vQTL) may serve as an indicator of underlying GEI effects. The aim of this study was to investigate GEI effects on dental caries by prioritizing variants from genome-wide vQTL analysis. First, we identified vQTLs from ~4.3 M genome-wide variants in three cohorts of white children aged 3–5 (n = 396, n = 328, n = 773) using Levene’s test. A total of 39 independent vQTLs with p < 1 × 10−6 were identified, some of which were located in or near genes with plausible biological roles in dental caries (IGFBP7, SLC5A8, and SHH involved in tooth development and enamel mineralization). Next, we used linear regression to test GEI effects on dental caries with the 39 prioritized variants and self-reported environmental factors (demographic, socioeconomic, behavioral, and dietary factors) in the three cohorts separately. We identified eight significant GEIs indicating that children with vQTL risk genotypes had higher caries experience if they had less educated parents, lower household/parental income, brushed their teeth less frequently, consumed sugar-sweetened beverages more frequently, were not breastfed, and were female. We reported the first genome-wide vQTL analysis of dental caries in children nominating several novel genes and GEI for further investigations.

Associations of PART1 and DEFB1 polymorphisms with Dental Caries in twelve-year-old children in Southern China: a cross-sectional study

OBJECTIVE

The aim of this study was to assess associations of PART1 rs27565 and DEFB1 rs11362 polymorphisms with the prevalence of dental caries in twelve-year-old children in Nandan County, Guangxi, China.

METHODS

A total of 1,061 children were included in this cross-sectional study and divided into two groups based on the Decayed, Missing and Filled teeth (DMFT) index: caries-free children (DMFT score = 0) and children with caries (DMFT score ≥ 1). Demographic characteristics, oral hygiene behaviour and dietary habits were collected through household records and questionnaires. Genomic DNA was extracted from buccal cells, and PART1 rs27565 and DEFB1 rs11362 polymorphisms were genotyped using a custom-designed 48-Plex single nucleotide polymorphism-scan kit.

RESULTS

Carriers of the PART1 rs27565 C allele (odds ratio [OR] = 1.338, 95% confidence interval (CI) = 1.015-1.764, P value = 0.039) and carriers of the DEFB1 rs11362 T allele (OR = 1.364, 95% CI = 1.056-1.762, P value = 0.017) had a higher risk of caries. Carriers of the PART1 rs27565 TC or CC genotype who ate sugary food more than once a week had a 1.6-fold higher risk of caries than TT carriers who ate sugary food at most once a week (OR = 1.579, 95% CI = 1.032-2.414, P value = 0.035). Carriers of the DEFB1 rs11362 CT or TT genotype who ate sugary food more than once a week had a 2.1-fold higher risk of caries than CC carriers who ate sugary food at most once a week (OR = 2.057, 95% CI = 1.438-2.940, P value < 0.001).

CONCLUSION

PART1 rs27565 and DEFB1 rs11362 polymorphisms were associated with caries in 12-year-old children in Nandan County, Guangxi, China. Carriers of the PART1 rs27565 TC or CC genotype and the DEFB1 rs11362 CT or TT genotype who ate sugary food more than once a week had a high probability of having caries.

Daily Exposure to a Cranberry Polyphenol Oral Rinse Alters the Oral Microbiome but Not Taste Perception in PROP Taster Status Classified Individuals

Diet and salivary proteins influence the composition of the oral microbiome, and recent data suggest that TAS2R38 bitter taste genetics may also play a role. We investigated the effects of daily exposure to a cranberry polyphenol oral rinse on taste perception, salivary proteins, and oral microbiota. 6-n-Propylthiouracil (PROP) super-tasters (ST, n = 10) and non-tasters (NT, n = 10) rinsed with 30 mL of 0.75 g/L cranberry polyphenol extract (CPE) in spring water, twice daily for 11 days while consuming their habitual diets. The 16S rRNA gene sequencing showed that the NT oral microbiome composition was different than that of STs at baseline (p = 0.012) but not after the intervention (p = 0.525). Principal coordinates analysis using unweighted UniFrac distance showed that CPE modified microbiome composition in NTs (p = 0.023) but not in STs (p = 0.096). The intervention also altered specific salivary protein levels (α-amylase, MUC-5B, and selected S-type Cystatins) with no changes in sensory perception. Correlation networks between oral microbiota, salivary proteins, and sensory ratings showed that the ST microbiome had a more complex relationship with salivary proteins, particularly proline-rich proteins, than that in NTs. These findings show that CPE modulated the oral microbiome of NTs to be similar to that of STs, which could have implications for oral health.

Role of Taste Receptors in Innate Immunity and Oral Health

Taste receptors are receptor proteins that detect ligands belonging to the 5 taste modalities: sweet, bitter, sour, salty, and umami. Taste receptors are not restricted to taste cells in taste buds; rather, they are distributed throughout the entire body. For example, solitary chemosensory cells (SCCs) and tuft cells express taste signal proteins and are present in several mucosae. In the airways, SCCs sense bacteria, allergens, viruses, and noxious stimuli and drive evasive behavior, neuroinflammation, and antibacterial responses. In the gut, tuft cells detect helminth infection and bacterial dysbiosis and initiate type II immune responses characterized by tissue remodeling. In the gingiva, SCCs detect oral pathogenic bacteria, evoke innate immune responses and release antimicrobial compounds in the epithelium, and regulate the microbiome composition. This review summarizes the most recent research on extragustatory taste receptors and their function in antibacterial defense. We also discuss how these findings have provided insights into the development of potential therapeutic strategies for mucosal bacterial infection and dental diseases.

TAS2R38 polymorphisms and oral diseases in Thais: a cross-sectional study

Background

Polymorphisms at positions 49, 262, and 296 in the TAS2R38 bitter taste receptor gene result in two common genetic haplotypes, PAV and AVI, named for the resulting amino acid substitutions. TAS2R38 genotype has been previously associated with caries risk in children. This study aimed to identify TAS2R38 polymorphisms among Thais and to explore any association between genotype and oral diseases.

Methods

Patients seeking care at Khon Kaen University Dental Hospital in Thailand were recruited to participate in the study. Saliva was collected for DNA extraction and genotyping. Patients completed a questionnaire to collect demographic variables and assess oral self-care behaviors. A calibrated dentist conducted an examination that included periodontal charting and recording of decayed, missing, and filled teeth (DMFT).

Results

A total of 250 patients (19–75 years) were enrolled in the study (116 males). Two haplotypes, PAV (67.2%) and AVI (32.8%) were found, resulting in 3 diplotypes; PAV/PAV (46.0%), PAV/AVI (42.4%) and AVI/AVI (11.6%). DMFT and periodontal status of 238 participants were recorded. The three diplotype groups were similar in age, sex, socio-economic indicators, oral self-care, and number of teeth. The odds of having periodontal disease, defined as at least one site with probing depth ≥ 5 mm, were lower in AVI/AVI and PAV/AVI compared with PAV/PAV. PAV/AVI tended to have less DMFT, while AVI/AVI tended to have more DMFT compared with PAV/PAV, however these trends did not reach statistical significance.

Conclusions

The frequency distribution of TAS2R38 genotypes was similar to that reported for other Asian populations. AVI/AVI genotype was associated with decreased prevalence of periodontal disease among Thai dental patients, whereas there was no significant association between TAS2R38 genotype and prevalence of tooth decay in this patient population.

DNA methylation in childhood dental caries and hypomineralization

OBJECTIVES

Epigenetic modulation of gene expression may be important in dental conditions, including dental caries and enamel hypomineralisation. The aims of this study were to assess associations between DNA methylation in cord blood leucocytes at birth, and caries experience and enamel hypomineralisation at six years of age.

METHOD

The study sample was from a birth cohort study of twins. Dental examinations at six years identified the presence/absence of (i) 'any caries' (untreated and treated caries), (ii) 'advanced caries' (untreated, advanced caries and/or past treatment) and (iii) hypomineralised second primary molars (HSPM). Genome-wide analysis of DNA methylation was performed on cord blood of 27 twin pairs (14 dizygotic and 13 monozygotic) using the Illumina Infinium MethylationEPIC BeadChip array. Differentially methylated CpGs (DMCpGs) and regions (DMRs) associated with each dental outcome were investigated, while accounting for the relatedness of twins. Results with a false discovery rate <0.05 were treated as statistically significant.

RESULTS

19 children had 'any caries', 15 had 'advanced' caries, and 18 had HSPM. No DMCpGs were associated with 'any caries', 16 and 19 DMCpGs were associated with 'advanced caries' and HSPM, respectively. DMRs were identified in association with all three outcomes. Genes implicated by these analyses included PBX1, ACAT2, LTBP3 and DDR1 which have been linked with dental tissue development in genetic studies.

CONCLUSION

This exploratory study identified differential methylation in several genes at birth associated with dental caries and HSPM at six years. Further research may provide valuable insights into aetiology of dental disease and/or reveal novel molecular-based approaches for early risk stratification.

CLINICAL SIGNIFICANCE

Epigenetic differences at birth are likely to be associated with dental health at six years and may be valuable biomarkers of early influences on dental health.

Analysis of ENAM gene single-nucleotide polymorphism rs3796704 with caries susceptibility in young adult Tamil population

Background:

Dental caries is as primeval as humanity, but still, investigations are undergoing regarding the etiopathogenesis behind this multifactorial disease. Genetics is known to play a vital role in the etiology behind dental caries in addition to environmental and socioeconomic factors. Genetic variations like single-nucleotide polymorphisms (SNPs) were extensively studied in the past decade to portray the etiopathogenesis contributing to dental caries.

Aim:

This investigation was undertaken to analyze the ENAM gene SNP rs3796704 with caries susceptibility in ethnic young adult Tamil population of India.

Materials and Methods:

Out of 370 patients included, 215 patients belonged to the high caries group (Decayed, Missing and Filled Tooth [DMFT] ≥2) and 155 patients belonged to the low caries group (DMFT ≤ 1). DNA was extracted from the blood of all the individuals. SNP genotyping was performed utilizing tetra-primer amplification refractory mutation system–polymerase chain reaction with specific primers.

Results:

The genotyping results showed that there were no differences in allelic (P = 0.114) and genotypic frequencies (P = 0.159) between the high caries and low caries groups.

Conclusion:

Future studies can be conducted in larger samples and different ethnicities around the globe to analyze the role played by SNPs of enamel formation genes in cariogenesis.

Genome-Wide Association Study (GWAS) of dental caries in diverse populations

BACKGROUND

Dental caries is one of the most common chronic diseases and is influenced by a complex interplay of genetic and environmental factors. Most previous genetic studies of caries have focused on identifying genes that contribute to dental caries in specific ethnic groups, usually of European descent.

METHODS

The aim of this study is to conduct a genome-wide association study (GWAS) to identify associations affecting susceptibility to caries in a large multiethnic population from Argentina, the Philippines, Guatemala, Hungary, and the USA, originally recruited for studies of orofacial clefts (POFC, N = 3686). Ages of the participants ranged from 2 to 12 years for analysis of the primary dentition, and 18-60 years for analysis of the permanent dentition. For each participant, dental caries was assessed by counts of decayed and filled teeth (dft/DFT) and genetic variants (single nucleotide polymorphisms, SNPs) were genotyped or imputed across the entire genome. Caries was analyzed separately for the primary and permanent dentitions, with age, gender, and presence/absence of any type of OFC treated as covariates. Efficient Mixed-Model Association eXpedited (EMMAX) was used to test genetic association, while simultaneously accounting for relatedness and stratification.

RESULTS

We identified several suggestive loci (5 × 10-8 < P < 5 × 10-6) within or near genes with plausible biological roles for dental caries, including a cluster of taste receptor genes (TAS2R38, TAS2R3, TAS2R4, TASR25) on chromosome 7 for the permanent dentition analysis, and DLX3 and DLX4 on chromosome 17 for the primary dentition analysis. Genome-wide significant results were seen with SNPs in the primary dentition only; however, none of the identified genes near these variants have known roles in cariogenesis.

CONCLUSION

The results of this study warrant further investigation and may lead to a better understanding of cariogenesis in diverse populations, and help to improve dental caries prediction, prevention, and/or treatment in future.

Arrest of root caries with an adjuvant chlorhexidine-fluoride varnish over a 12-months observation period: a QLF-analyzed, placebo-controlled, randomized, clinical trial (RCT)

This study aimed at evaluating the effectiveness of an adjuvant chlorhexidine–fluoride varnish (Cervitec F) for prevention and arrest of root caries on elderly participants using quantitative light-induced fluorescence (QLF). 23 participants with two or three non-cavitated root carious lesions were included and assigned to three groups of different varnishes (CF: Cervitec F, P: placebo, DP: Duraphate). Agents were applied once to root surface at baseline and in follow-up after 3, 6 and 9 months. The lesions were assessed clinically and with QLF. QLF-images were analyzed regarding fluorescence loss (ΔF), lesion volume (ΔQ) and bacterial activity (ΔR) before (t₀), after 14 days (t₁), 6- (t₂) and 12-months (t₃). CF showed a significant difference between t₀ and t₃: ∆F (− 12.51 [15.41] vs. − 7.80 [16.72], p = 0.012), ∆Q (− 2339.97 (20,898.30) vs. − 751.82 (5725.35), p < 0.001), ∆R (23.80 [41.70] vs. 7.07 [37.50], p = 0.006). Independently of the varnish application, preventive care seems positively influence the root caries progress. Although within CF group the strongest effect was observed, no superiority of a specific varnish application was confirmed over a 12-months QLF observation period. Extra topical fluoride can help remineralise dentin lesions and QLF can be used as a measurement method to determine changes in the dentin lesions.

Association Between the TaqI (rs731236 T>C) Gene Polymorphism and Dental Caries Risk: A Meta-analysis

Objective: This study investigated the association of the TaqI (rs731236 T>C) polymorphism in the VDR gene with dental caries.

Methods: A comprehensive literature search was performed in PubMed, Web of Science, Embase, SinoMed (the Chinese biomedical literature service system), and the Wiley Online Library. Overall comparisons and subgroup analyses based on ethnicity and the presence of dental caries in dentition were performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess associations between gene polymorphisms and the risk of dental caries.

Results: Seven articles were included in this meta-analysis. The pooled results revealed a significant association of the TaqI (rs731236 T>C) polymorphism with dental caries in the allele contrast model (C vs. T: OR = 1.24, 95% CI = 1.07–1.44, I² = 42%, p = 0.005) and in the recessive genetic model (CC vs. TT/CT: OR = 1.38, 95% CI = 1.03–1.84, I² = 0%, p = 0.03). A stratified analysis based on ethnicity revealed a significant association between the TaqI (rs731236 T>C) polymorphism and the risk of dental caries in Asians (C vs. T: OR = 1.28, 95% CI = 1.06–1.54, I² = 60%, p = 0.009). Subgroup analysis based on the presence of dental caries in dentition found a significant association of the TaqI (rs731236 T>C) polymorphism with permanent tooth caries in the allele contrast model (C vs. T: OR = 1.40, 95% CI = 1.11–1.77, I² = 76%, p = 0.005) and the recessive genetic model (CC vs. TT/CT: OR = 1.44, 95% CI = 1.03–2.00, I² = 0%, p = 0.03).

Conclusion: The results of this meta-analysis suggest that the C allele and CC genotype of the TaqI (rs731236 T>C) polymorphism in the VDR gene are associated with an increased risk of dental caries.

Association of genetic variants in enamel-formation genes with dental caries: A meta- and gene-cluster analysis

Previous studies have reported the association between multiple genetic variants in the enamel-formation genes and the risk of dental caries with inconsistent results. We performed a systematic literature search of the PubMed, Cochrane Library, HuGE and Google Scholar databases for studies published before March 21, 2020 and conducted meta-, gene-based and gene-cluster analysis on the association between genetic variants in the enamel-formation genes and the risk of dental caries. We identified 21 relevant publications including a total of 24 studies for analysis. The genetic variant rs17878486 in AMELX was significantly associated with dental caries risk (OR = 1.40, 95% CI: 1.02–1.93, P = 0.037). We found no significant association between the risk of dental caries with rs12640848 in ENAM (OR = 1.15, 95% CI: 0.88–1.52, P = 0.310), rs1784418 in MMP20 (OR = 1.07, 95% CI: 0.76–1.49, P = 0.702) and rs3796704 in ENAM (OR = 1.06, 95% CI: 0.96–1.17, P = 0.228). Gene-based analysis indicated that multiple genetic variants in AMELX showed joint association with the risk of dental caries (6 variants; P < 10⁻⁵), so did genetic variants in MMP13 (3 variants; P = 0.004), MMP2 (3 variants; P < 10⁻⁵), MMP20 (2 variants; P < 10⁻⁵) and MMP3 (2 variants; P < 10⁻⁵). The gene-cluster analysis indicated a significant association between the genetic variants in this enamel-formation gene cluster and the risk of dental caries (P < 10⁻⁵). The present meta-analysis revealed that genetic variant rs17878486 in AMELX was associated with dental caries, and multiple genetic variants in the enamel-formation genes jointly contributed to the risk of dental caries, supporting the role of genetic variants in the enamel-formation genes in the etiology of dental caries.

A New Model for Caries Risk Prediction in Teenagers Using a Machine Learning Algorithm Based on Environmental and Genetic Factors

Dental caries is a multifactorial disease that can be caused by interactions between genetic and environmental risk factors. Despite the availability of caries risk assessment tools, caries risk prediction models incorporating new factors, such as human genetic markers, have not yet been reported. The aim of this study was to construct a new model for caries risk prediction in teenagers, based on environmental and genetic factors, using a machine learning algorithm. We performed a prospective longitudinal study of 1,055 teenagers (710 teenagers for cohort 1 and 345 teenagers for cohort 2) aged 13 years, of whom 953 (633 teenagers for cohort 1 and 320 teenagers for cohort 2) were followed for 21 months. All participants completed an oral health questionnaire, an oral examination, biological (salivary and cariostate) tests, and single nucleotide polymorphism sequencing analysis. We constructed a caries risk prediction model based on these data using a random forest with an AUC of 0.78 in cohort 1 (training cohort). We further verified the discrimination and calibration abilities of this caries risk prediction model using cohort 2. The AUC of the caries risk prediction model in cohort 2 (testing cohort) was 0.73, indicating high discrimination ability. Risk stratification revealed that our caries risk prediction model could accurately identify individuals at high and very high caries risk but underestimated risks for individuals at low and very low caries risk. Thus, our caries risk prediction model has the potential for use as a powerful community-level tool to identify individuals at high caries risk.

Single nucleotide polymorphisms of taste genes and caries: a systematic review and meta-analysis

OBJECTIVE

The aim of the present study was to systematically review the literature investigating the single nucleotide polymorphisms (SNP) related to taste genes and their influence on caries.

MATERIAL AND METHODS

Search was performed in five databases to respond to the question: 'Are the polymorphisms of taste genes associated with dental caries?'. Studies in humans were included. Assessment of quality of studies, meta-analysis and sensitivity analysis were performed.

RESULTS

Seven studies were included in the systematic review and two in meta-analysis. Most of studies (71.4%) presented cohort design with low-level of evidence. A total of 4,032 individuals were evaluated. Four different taste genes (TAS1R2, TAS2R38, TAS1R3 and GLUT2) and 12 SNPs were reported. Most SNPs of taste genes showed a protective effect of the minor allele against dental caries. Meta-analysis included the SNP rs713598 placed in the TAS2R38 gene. The results suggest an effect of the heterozygote genotype (CG), which was associate with low caries experience (OR = 0.35 CI95% [0.17-0.75]). However, the genotype GG was not associated (OR = 0.17 CI95% [0.03-1.04]). Sensitivity analysis showed an important influence of one study in the results.

CONCLUSIONS

SNP of taste genes seems to be associated with caries experience. Causal inferences should be interpreted with caution and the results must be replicated in different populations.

Comparison of dental caries (DMFT and DMFS indices) between asthmatic patients and control group in Iran: a meta-analysis

Background

The association between caries index, which is diagnosed by Decayed, Missing, and Filled Teeth (DMFT), and asthma has been assessed in several studies, which yielded contradictory results. Meta-analysis is the statistical procedure for combining data from multiple studies and reducing the differences among parameters due to the increased number of studies involved in the analysis process. Therefore, the present study aimed to determine the relationship between dental caries using decayed, missing, filled teeth indices (DMFT, dmft, and DMFS indices) and asthma using meta-analysis.

Methods

Databases were searched using such keywords as “Asthma,” “Caries,” “DMFT,” “DMFS,” “Iran,” and OR operators, AND, and NOT. After the elimination of duplicate documentation, the articles which met the inclusion criteria were selected. Quality assessment was performed based on the Newcastle-Ottawa Quality Checklist (NOS). After that, standardized mean difference (SMD) of DMFT, dmft, and Decayed, Missing, and Filled Surfaces (DMFS) indices were estimated.

Results

The number of 10 evidence was extracted out of nine studies in which mean oral health indices were compared between asthmatic patients and the control group. Out of 10 evidences that examined the association of DMFT, dmft, and DMFS with asthma, these indices were higher in asthmatic patients than the control group in seven cases. In three cases, these differences were statistically significant. The SMD of DMFT, dmft, and DMFS indices between asthmatic patients and the control group at the confidence level of 95% were reported as 0.29 (− 0.05, 0.62), 0.48 (− 0.20, 1.17), and − 0.05(− 0.30, 0.21), respectively.

Conclusion

According to the results, the prevalence of dental caries is higher among patients with asthma than in the control group. Therefore, having asthma could be considered a risk factor for the development of dental caries.

Beta-defensin 1 gene polymorphisms in the pathologies of the oral cavity-Data from meta-analysis: Association only with rs1047031 not with rs1800972, rs1799946, and rs11362

OBJECTIVES

The purpose of this meta-analysis was to reveal a potential association of the four functional polymorphisms in human Beta-defensin 1 (DEFB1) gene: rs1047031(c*5G > A) at 3'UTR and rs11362 (-20 G > A), rs1800972(-44 C > G), and rs1799946 (-52 G > A) at 5'UTR with the risk of common oral cavity pathologies that included periodontitis, caries, lichen planus, and recurrent aphthous stomatitis.

METHODS

The relevant studies were obtained by the two researchers from PubMed, Scopus, and Web of Science up to April 29, 2020. The manual search of the reference lists was also performed. Studies on DEFB1 gene polymorphisms and oral cavity disorders, using the case-control genetic association analysis approach, and published as full texts in English were included. To assess the association strength, odds ratios (ORs) with their 95% confidence intervals (CIs) were extracted.

RESULTS

Thirteen publications met the inclusion criteria and were incorporated in this meta-analysis. Statistically significant values of the association tests were found only for the rs1047031 polymorphism. Allele distribution in the rs1047031 polymorphism was significantly associated with susceptibility to oral cavity pathologies (adjusted P value = 0.003). The rare variant allele carriers had a significantly higher risk for oral disasters under recessive (CC vs CT + TT), and CC vs CT models. No significant correlations between rs11362, rs1800972, and rs1799946 and the risk of oral pathologies were revealed.

CONCLUSIONS

Significant association between rs1047031 polymorphism and risk of oral pathologies has been found, and therefore, we suggest to include this polymorphism in future research concerning the genetic background of the oral cavity diseases.

Genes in the pathway of tooth mineral tissues and dental caries risk: a systematic review and meta-analysis

OBJECTIVES

To perform a systematic review of the literature, investigating the influence of tooth mineral tissues genes on dental caries.

MATERIALS AND METHODS

Five databases were searched. Only human studies with cross-sectional, longitudinal, and case-control design were included. Meta-analysis was performed for each polymorphism, providing allele and genotype estimates. A meta-analysis was performed, pooling several polymorphisms for each gene. A Funnel Plot and Egger's test were also performed.

RESULTS

A total of 1124 records were found. Of these, 25 papers were included in the systematic review and 18 in the meta-analysis. Most of the studies (52%) were of medium quality. With regard to the allele analysis, the T allele of rs134136 (TFIP11) (OR 1.51; 95%CI 1.02-2.22) showed an association with high experience of caries and the summarization of polymorphisms investigated in the TFIP11 gene, after exclusion of SNP linkage disequilibrium, showed an association with caries experience (OR 1.64; 95%CI 1.08-2.50). An analysis of the homozygous genotype did not show any significant association. The pooled SNPs of AMBN showed associations with caries (OR 0.45; 95%CI 0.29-0.72). The pooled polymorphisms of AMELX were associated with caries experience (OR 1.78; 95%CI 1.23-2.56). In the analysis of the homozygous genotype, no SNP showed a significant association. Egger's test showed no significant publication bias for all models (p > 0.05).

CONCLUSION

The present findings showed that the genes TFIP11, AMBN, and AMELX play an important role in dental caries.

CLINICAL RELEVANCE

Several single nucleotide polymorphisms related to the genes in the formation of tooth mineral are linked to the occurrence of dental caries, and these genes have proved to be important for an explanation of differences in the risk of dental caries.

Association between rs11362 polymorphism in the beta-defensin 1 (DEFB1) gene and dental caries: A meta-analysis

OBJECTIVES

Beta-defensin 1, encoded by the DEFB1 gene, is an important molecule that confers protection from dental caries. Numerous studies have been conducted on the rs11362 polymorphism in the DEFB1 gene. We evaluated the results from studies that have investigated the association between rs11362 polymorphism and dental caries, through a meta-analysis.

METHODS

This meta-analysis was designed according to the PRISMA statement guideline. Electronic databases (PubMed, Web of Science, Scopus, and Cochrane Library) were scanned by two independent researchers. The publication bias was determined by statistical analyses using funnel plot, Egger regression test, and Begg and Mazumdar rank correlation test. Heterogeneity was evaluated using the chi-square test, tau-square, and Higgins I² test. Odds ratio (OR) was used to measure the effect size.

RESULTS

Rank correlation and regression procedures showed the absence of publication bias in the meta-analysis (p > 0.05). The DEFB1 rs11362 polymorphism in the heterozygous (CC vs. CT: OR = 2.20, 95% confidence interval (CI): 1.17, 4.10; p = 0.014) and dominant (CC vs. CT + TT: OR = 3.11, 95% CI: 1.18, 8.21; p = 0.022) models in the permanent dentition subgroup showed significant differences. However, there was no significant difference between any model in either the deciduous dentition (p > 0.05) or the mixed dentition subgroups (p > 0.05).

CONCLUSIONS

This meta-analysis suggests that the DEFB1 rs11362 polymorphism is associated with dental caries in permanent dentition. Moreover, individuals with the TT genotype were found to have seven times higher risk of dental caries than individuals with the CC genotype. There was no such association or statistical difference observed for deciduous and mixed dentitions.

AMELX Gene Association with Dental Caries in Iranian Adults

Dental decay is a disease that is greatly affected by environmental components, but recently there have been an increasing number of documents supporting a genetic factor in the development of caries. The purpose of this study was to examine the association between dental caries and single-nucleotide polymorphisms in the AMELX gene. This research was carried out on 360 individuals of both sexes, who were referred to the dental school at the Shiraz University of Medical Sciences. In this research, individuals aged 20–65 years were divided into two groups: controls (decayed, missed, or filled teeth (DMFT) ≤ 5; n = 180) and cases (DMFT ≥ 14; n = 180). The tetra-primer ARMS-PCR technique was performed for genotyping the DNA extracted from blood cells. Analysis of the AMELX rs946252 polymorphism showed that the T allele of rs946252 was a significant protective factor against dental caries in Iranian adults (T vs. C: OR = 0.70, 95% CI: 0.49–0.98, P = 0.04). We demonstrated the significant differences in the genotype frequencies under two genetic models: overdominant (TC vs. TT + CC: OR 0.35, 95% CI 0.19–0.64, P = 0.0006) and recessive (CC vs. TC + TT: OR 2.57, 95% CI 1.39–4.76, P = 0.002). Our results show that the SNPs of the AMELX gene may be related with susceptibility to dental caries in Iranian adults.

Vitamin D Deficiency and Oral Health: A Comprehensive Review

Vitamin D (VD) levels have been gaining growing attention in Oral Health. During growth and adulthood, VD deficiency (VDD) is associated with a wide variety of oral health disorders, and impaired VD synthesis may expedite some of these conditions. In children, severe VDD can induce defective tooth mineralization, resulting in dentin and enamel defects. As a consequence, these defects may increase the risk of the onset and progression of dental caries. Further, VDD has been associated with higher prevalence of periodontitis and gingival inflammation, and several recent preclinical and clinical studies have unveiled potential pathways through which Vitamin D may interact with the periodontium. VDD correction through supplementation may contribute to a successful treatment of periodontitis; however, alveolar bone regeneration procedures performed in baseline VDD patients seem more prone to failure. Vitamin D may also be linked with some oral pathology entities such as certain oral cancers and events of osteonecrosis of the jaw. This review aims to provide comprehensive evidence of how VD levels should be considered to promote good oral health, and to summarize how VDD may hamper oral development and its role in certain oral conditions.

Association of LTF, ENAM, and AMELX polymorphisms with dental caries susceptibility: a meta-analysis

Background

This meta-analysis evaluated the association of LTF, ENAM, and AMELX polymorphisms with dental caries susceptibility.

Methods

We searched the Scopus, PubMed/Medline, Web of Science, and Cochrane Library databases to retrieve articles published by October 2019. Review Manager 5.3 software was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). The results of publication bias tests were retrieved by Comprehensive Meta-Analysis 2.0 software.

Results

A total of 150 relevant records were identified; out of which, 16 were entered into the analysis (4 studies assessed LTF, 11 ENAM, and 11 AMELX polymorphisms). Of all polymorphisms, there was a significant association only between ENAM rs3796704 polymorphism and dental caries susceptibility. Both ENAM rs3796704 and AMELX rs17878486 polymorphisms had a significant association with dental caries risk in the Caucasian ethnicity and the studies including caries-free control group.

Conclusions

The results of this meta-analysis showed that the G allele and the GG genotype of ENAM rs3796704 were associated with an increased risk of caries in the case group compared with the control group. But there was no association between LTF rs1126478, ENAM (rs1264848 and rs3796703), and AMELX (rs946252, rs17878486, and rs2106416) polymorphisms and dental caries susceptibility.

Polymorphism in the CAVI gene, salivary properties and dental caries

Objectives: Carbonic anhydrase (CA) VI is supposed to take part in pH or buffering capacity regulation, which can influence the caries risk of an individual. Its expression in the saliva can be modified by single nucleotide polymorphism (SNP). The aim was to investigate SNP in the CA VI gene in relation to active dental caries and physiochemical properties of saliva.Materials and methods: One hundred and thirty participants aged 11-16 years were involved. Clinical examinations were carried out using standardized WHO criteria, DMFT/DMFS and white spot lesions score was evaluated. Saliva samples were examined for salivary properties and CA VI concentration. DNA evaluated in the investigation was extracted from the buccal smear. Three SNP within CAVI gene (rs2274327; rs2274328; rs2274333) were selected and genotyping was performed.Results: In the active caries group, the mean CAVI concentration was significantly lower than in caries free group (p = .014). No association between increased or decreased risk of caries and analysed SNPs was found. There were some significant relations concerning SNPs and salivary buffer capacity and flow rate in rs2274327 and rs2274328.Conclusions: Polymorphism in the CAVI gene can affect salivary properties but there is no direct connection with dental caries.

Genetic Differences in Taste Receptors: Implications for the Food Industry

Inborn genetic differences in chemosensory receptors can lead to differences in perception and preference for foods and beverages. These differences can drive market segmentation for food products as well as contribute to nutritional status. This knowledge may be essential in the development of foods and beverages because the sensory profiles may not be experienced in the same way across individuals. Rather, distinct consumer groups may exist with different underlying genetic variations. Identifying genetic factors associated with individual variability can help better meet consumer needs through an enhanced understanding of perception and preferences. This review provides an overview of taste and chemesthetic sensations and their receptors, highlighting recent advances linking genetic variations in chemosensory genes to perception, food preference and intake, and health. With growing interest in personalized foods, this information is useful for both food product developers and nutrition health professionals alike.

Investigation of Interaction between Vitamin D Receptor Gene Polymorphisms and Environmental Factors in Early Childhood Caries in Chinese Children

Background

Early childhood caries is a multifactorial disease involving interactions between genetic and environmental risk factors. The aim of this study was to examine the effects of vitamin D receptor (VDR) gene polymorphisms and gene-environment interactions on the etiology of, and susceptibility to, caries in Chinese children aged 3-5 years.

Methods

Children (n = 549) were divided into three groups according to caries risk: high (decayed, missing, filled teeth (dmft) index > 4; n = 148), moderate (dmft = 1-4; n = 156), and caries-free (n = 245). A questionnaire was designed to collect demographic information, dietary habits, and oral hygiene practices, and dental plaque samples were collected to test acidogenic activity of bacteria. Genomic DNA was extracted from the buccal mucosa, and the VDR polymorphisms rs7975232, rs1544410, rs11568820, rs10735810, and rs731236 were genotyped using TaqMan assays.

Results

There were no differences among the caries risk groups in frequencies of the rs7975232, rs731236, rs1544410, or rs11568820 polymorphisms (χ ² test, P > 0.05); however, the frequency of the rs10735810 CC genotype was clearly higher in the high caries risk group than in the control and moderate caries risk groups (39.2%, 25.6%, and 30.6%, respectively; χ ² test, P=0.028). In multivariate analysis of genotypes and behavioral factors, rs7975232, rs731236, rs1544410, rs11568820, and rs10735810 were not associated with deciduous tooth decay (χ ² test, P > 0.05).

Conclusion

We conclude that these VDR polymorphisms cannot be used as markers for identification of Chinese children at increased risk of dental caries, when combined with environmental factors. Future studies are needed to replicate these initial findings and better assess the risk of caries in deciduous teeth.

Gingival solitary chemosensory cells are immune sentinels for periodontitis

Solitary chemosensory cells (SCCs) are epithelial sentinels that utilize bitter Tas2r receptors and coupled taste transduction elements to detect pathogenic bacterial metabolites, triggering host defenses to control the infection. Here we report that SCCs are present in mouse gingival junctional epithelium, where they express several Tas2rs and the taste signaling components α-gustducin (Gnat3), TrpM5, and Plcβ2. Gnat3-/- mice have altered commensal oral microbiota and accelerated naturally occurring alveolar bone loss. In ligature-induced periodontitis, knockout of taste signaling molecules or genetic absence of gingival SCCs (gSCCs) increases the bacterial load, reduces bacterial diversity, and renders the microbiota more pathogenic, leading to greater alveolar bone loss. Topical treatment with bitter denatonium to activate gSCCs upregulates the expression of antimicrobial peptides and ameliorates ligature-induced periodontitis in wild-type but not in Gnat3-/- mice. We conclude that gSCCs may provide a promising target for treating periodontitis by harnessing innate immunity to regulate the oral microbiome.

Dental caries: Genetic and protein interactions

OBJECTIVE

To present a genetic and protein interaction analysis associated with dental caries.

MATERIAL AND METHODS

The first step was to conduct a systematic literature review (SLR) through an electronic database search. Case-controls that reported associations between genes and dental caries were the main type of study design used as inclusion criteria, retrieved from the PubMed and the Virtual Health Library databases, comprising the chronological range from 1982 to 2017. The SLR was guided by PRISMA protocol and the methodological quality of the studies was established through Newcastle-Ottawa Scale (NOS). In the second step, the String Protein Interaction (SPI) approach was used to analyze protein interaction (by esyN software) and also the Ingenuity Pathway Analysis (IPA) to check biological pathways associated with dental caries genes.

RESULTS

A total of 51 articles were included to perform this SLR, describing a number of 27 genes associated with dental caries development. At the genetic level, 23 genes have at least one other gene with which they interact. The genes TUFT1, VDR, TFIP11, LTF, HLA-DRB1, MMP2, MMP3 and MUC5B were shown to be connected in interactive networks by at least 10 other genes.

CONCLUSION

It is essential to apprehend the multifactorial pattern of inheritance in human disease. This study presents pathways which may be directly correlated with several dental caries phenotype and this contributes to a better understanding of this disease, opening up a wider range of biotechnology options for its effective control in the future.

Association of ENAM, TUFT1, MMP13, IL1B, IL10 and IL1RN gene polymorphism and dental caries susceptibility in Chinese children

OBJECTIVE

To investigate the association between single nucleotide polymorphisms (SNPs) in six candidate genes (enamelin [ ENAM]; tuftelin 1 [ TUFT1]; matrix metallopeptidase 13 [ MMP13]; interleukin 1 beta [ IL1B]; interleukin 10 [ IL10]; interleukin 1 receptor antagonist [ IL1RN]) and dental caries in children from northwest China.

METHODS

This case-control study enrolled children (12-15 years) who underwent routine dental examinations. The children were divided into two groups based on the presence of dental caries. A saliva sample was collected and seven SNPs (rs3806804A/G in ENAM, rs3811411T/G in TUFT1, rs2252070A/G and rs597315A/T in MMP13, rs1143627C/T in IL1B, rs1800872A/C in IL10 and rs956730G/A in IL1RN) were genotyped.

RESULTS

A total of 357 children were enrolled in the study: 161 with dental caries and 196 without dental caries. No significant difference was found in the alleles and genotypes of five genes ( ENAM, TUFT1, MMP13, IL10 and IL1RN) between those with and without dental caries. A significant relationship was found between the IL1B rs1143627C/T polymorphism and dental caries susceptibility with those carrying the rs1143627CT genotype having a lower risk of dental caries compared with those carrying the CC genotype (odds ratio 0.557; 95% confidence interval 0.326, 0.952).

CONCLUSION

The IL1B rs1143627C/T polymorphism may be associated with dental caries susceptibility in children from northwest China.

Carbonic Anhydrase 6 Gene Variation influences Oral Microbiota Composition and Caries Risk in Swedish adolescents

Carbonic anhydrase VI (CA6) catalyses the reversible hydration of carbon dioxide in saliva with possible pH regulation, taste perception, and tooth formation effects. This study assessed effects of variation in the CA6 gene on oral microbiota and specifically the acidophilic and caries-associated Streptococcus mutans in 17-year old Swedish adolescents (n = 154). Associations with caries status and secreted CA6 protein were also evaluated. Single Nucleotide Polymorphisms (27 SNPs in 5 haploblocks) and saliva and tooth biofilm microbiota from Illumina MiSeq 16S rDNA (V3-V4) sequencing and culturing were analysed. Haploblock 4 (rs10864376, rs3737665, rs12138897) CCC associated with low prevalence of S. mutans (OR (95% CI): 0.5 (0.3, 0.8)), and caries (OR 0.6 (0.3, 0.9)), whereas haploblock 4 TTG associated with high prevalence of S. mutans (OR: 2.7 (1.2, 5.9)) and caries (OR: 2.3 (1.2, 4.4)). The TTG-haploblock 4 (represented by rs12138897(G)) was characterized by S. mutans, Scardovia wiggsiae, Treponema sp. HOT268, Tannerella sp. HOT286, Veillonella gp.1 compared with the CCC-haploblock 4 (represented by rs12138897(C)). Secreted CA6 in saliva was weakly linked to CA6 gene variation. In conclusion, the results indicate that CA6 gene polymorphisms influence S. mutans colonization, tooth biofilm microbiota composition and risk of dental caries in Swedish adolescents.

Host genetics role in the pathogenesis of periodontal disease and caries

BACKGROUND

This study aimed to produce the latest summary of the evidence for association of host genetic variants contributing to both periodontal diseases and caries.

MATERIALS AND METHODS

Two systematic searches of the literature were conducted in Ovid Medline, Embase, LILACS and Cochrane Library for large candidate gene studies (CGS), systematic reviews and genome-wide association studies reporting data on host genetic variants and presence of periodontal disease and caries.

RESULTS

A total of 124 studies were included in the review (59 for the periodontitis outcome and 65 for the caries outcome), from an initial search of 15,487 titles. Gene variants associated with periodontitis were categorized based on strength of evidence and then compared with gene variants associated with caries. Several gene variants showed moderate to strong evidence of association with periodontitis, although none of them had also been associated with the caries trait.

CONCLUSIONS

Despite some potential aetiopathogenic similarities between periodontitis and caries, no genetic variants to date have clearly been associated with both diseases. Further studies or comparisons across studies with large sample size and clear phenotype definition could shed light into possible shared genetic risk factors for caries and periodontitis.

Pediatric Adapted Liking Survey: A Novel, Feasible and Reliable Dietary Screening in Clinical Practice

PURPOSE

Rapid yet useful methods are needed to screen for dietary behaviors in clinical settings. We tested the feasibility and reliability of a pediatric adapted liking survey (PALS) to screen for dietary behaviors and suggest tailored caries and obesity prevention messages.

METHODS

In an observational study, children admitted to a pediatric emergency department (PED) for nonurgent care were approached to complete the PALS (33 foods, 4 nonfoods including brushing teeth). Measured height/weight were used for body mass index (BMI) percentile determination. Feasibility was assessed by response rate and PALS completion time. Reliability was assessed by internal consistency of food groups and test-retest reliability for PED-home reported PALS.

RESULTS

PALS was completed by 144 children (96% of approached) - 54% male (average age = 11 ± 3 years) with diversity in family income (43% publicly insured), race/ethnicity (15% African American, 33% Hispanic, 44% Caucasian) and adiposity (3% underweight, 50% normal, 31% overweight, 17% obese, 8% extremely obese). The average completion time was 3: 52 min, and conceptual food groups had reasonable internal reliability. From 57% (n = 82) with PED-home completion, PALS had a good/excellent test-retest reliability. Relative preferences for sweets versus brushing teeth identified unique groups of children for tailored prevention messages (high sweet/brushing preference, sweets > brushing, brushing > sweets). Females with higher adiposity reported significantly greater preference for sweet/high-fat foods, independently of demographic variables; the relationship was nonsignificant in males and with the other food groups.

CONCLUSION

The PALS appears to be a fast, feasible and reliable dietary screener in a clinical setting to assist in forming tailored diet-related messages for dental caries and obesity prevention.

[Association between the dental caries and the human leucocyte antigen DQB1 allele polymorphisms among the Uygur and Han children in Xinjiang]

OBJECTIVE

This study aims to investigate the association between human leucocyte antigen (HLA)-DQB1 allele polymorphisms and the presence dental caries among the Uygur and Han children in Xinjiang.

METHODS

HLA-DQB1 allele in the Uygur and Han children with dental caries and healthy control in Xinjiang was tested (n=40) using the polymerase chain reaction-sequence specific primer (PCR-SSP) DNA parting technology.

RESULTS

A total of five specific loci were detected in the HLA-DQB1 locus among the Uygur and Han children. The frequency of the HLA-DQB1*02 allele in the Han group with severe caries (12.5%) was significantly lower than in the control group (32.5%) (P<0.05, OR=0.297). Moreover, the frequency of the HLA-DQB1*05 allele in the Uygur group with severe caries (37.5%) was significantly higher than in the control group (17.5%) (P<0.05, OR=2.829).

CONCLUSIONS

Caries susceptibility among the Uygur and Han children in Xinjiang is related to the HLA-DQB1 allele. The HLA-DQB1*02 allele may protect against caries among the Han children, whereas the HLA-DQB1*05 allele may be responsible for the susceptibility of the Uygur children to caries.

Redefining the Phenotype of Dental Caries

Dental caries is a multifactorial infectious disease and a major public health problem estimated to affect 60-90% of school children as well as a vast number of adults. The aim of this work was to define patterns of progression of the disease based on longitudinal data in contrast to using a cross-sectional assessment. dmft/DMFT scores were collected at ages 5, 12, 14, 16, 17, and 18 from 876 individuals. We tested our newly defined phenotypes for association with genetic variants in genes shown to be associated with caries. We generated genotyping data using Taqman chemistry in markers of genes involved in processes such as enamel formation and salivary contributions. Kallikrein 4 (KLK4) was found to show a significant association with the created phenotypes (p = 0.0008 in a recessive model for low caries experience in the primary dentition vs. high caries experience in the primary dentition, and p = 0.0004 in a recessive model for caries free primary dentition vs. high caries experience in the primary dentition).

Factors Influencing the Phenotypic Characterization of the Oral Marker, PROP

In the last several decades, the genetic ability to taste the bitter compound, 6-n-propyltiouracil (PROP) has attracted considerable attention as a model for understanding individual differences in taste perception, and as an oral marker for food preferences and eating behavior that ultimately impacts nutritional status and health. However, some studies do not support this role. This review describes common factors that can influence the characterization of this phenotype including: (1) changes in taste sensitivity with increasing age; (2) gender differences in taste perception; and (3) effects of smoking and obesity. We suggest that attention to these factors during PROP screening could strengthen the associations between this phenotype and a variety of health outcomes ranging from variation in body composition to oral health and cancer risk.

The relationship between vitamin D receptor gene polymorphism and deciduous tooth decay in Chinese children

Background

In the present study, we explored the link between vitamin D receptor (VDR) BsmI, TaqI, ApaI and FokI gene polymorphisms with deciduous tooth decay in Chinese children.

Methods

Our study included 380 Chinese children aged 4–7 years, whose DNA sample was collected from the buccal mucosa. VDR gene polymorphisms was determined by PCR-RFLP.

Results

The adjusted logistic regression analysis demonstrated that BsmI containing the Bb genotype was linked with the increased risk of deciduous tooth decay (OR = 1.856, 95% CI = [1.184, 2.908], p = 0.007). However, VDR polymorphisms ApaI, TaqI and FokI were not associated with deciduous tooth decay (ApaI: OR = 0.839, 95% CI = [0.614, 1.145], p = 0.268; TaqI: OR = 1.150, 95% CI = [0.495, 2.672], p = 0.744; FokI: OR = 0.856, 95% CI = [0.616, 1.191], p = 0.356).

Conclusions

Our results showed that VDR BsmI polymorphism was associated with the risk of deciduous tooth decay in Chinese children aged 4–7 years. However, the specific mechanism remains to further verify through experiment.

Single Nucleotide Polymorphism in the Aetiology of Caries: Systematic Literature Review

Recent progress in the field of molecular biology and techniques of DNA sequence analysis allowed determining the meaning of hereditary factors of many common human diseases. Studies of genetic mechanisms in the aetiology of caries encompass, primarily, 4 main groups of genes responsible for (1) the development of enamel, (2) formation and composition of saliva, (3) immunological responses, and (4) carbohydrate metabolism. The aim of this study was to present current knowledge about the influence of single nucleotide polymorphism (SNP) genetic variants on the occurrence of dental caries. PubMed/Medline, Embase, and Cochrane Library databases were searched for papers on the influence of genetic factors connected with SNP on the occurrence of dental caries in children, teenagers, and adults. Thirty original papers written in English were included in this review. Study groups ranged from 30 to 13,000 subjects. SNPs were observed in 30 genes. Results of the majority of studies confirm the participation of hereditary factors in the aetiology of caries. Three genes, AMELX, AQP5, and ESRRB, have the most promising evidence based on multiple replications and data, supporting a role of these genes in caries. The review of the literature proves that SNP is linked with the aetiology of dental caries.