Maternal Smoking during Pregnancy Is Associated with Offspring Hypodontia

Evaluation of mandibular trabecular bone by fractal analysis in pediatric patients with hypodontia of the mandibular second premolar tooth

BACKGROUND

It is still unclear whether the trabecular structure of the jaw is different in individuals with hypodontia than in those without hypodontia; this is important for clinicians. The aim was to determine whether the mandibular trabecular bone structure of children and adolescents with hypodontia differs from the control group by using the fractal analysis (FA) method in this study.

METHODS

A total of 138 panoramic radiographs of 69 cases and 69 control subjects (mean age 13.2 ± 10.1) were evaluated. The age and gender of subjects in the case and control groups were matched. Three regions of interest (ROIs) were selected from the panoramic radiographs. ROI1 refers to the center of the ramus rising above the mandibular foramen. ROI2 refers to the area between the apical level of the mandibular molar and the upper border of the mandibular canal. ROI3, the missing tooth region, refers to the apical third of the mesial side of the erupting or fully erupted permanent mandibular first molar. Mann-Whitney U and Wilcoxon tests were used. p < 0.05 was accepted for the significance value.

RESULTS

The mean fractal dimension (FD) values of ROI1, ROI2, and ROI3 were 1,25, 1,20, and 1,13, respectively. The means FD values obtained from the ramus region were higher than the other regions (p < 0.05). The FD values did not differ significantly according to gender and age (p > 0.05). The FD values of the case group were lower than the control group for ROI3 (p < 0.05).

CONCLUSION

The results of this study showed that the mandibular trabecular bone quality of pediatric patients with one missing tooth was different from the healthy group. The difference in the mean FD values from the ROIs indicates that the ramus has a denser structure than the mandibular corpus. Clinicians should factor this into their dental treatment planning process.

Pan-cancer analysis reveals the characteristics and roles of tooth agenesis mutant genes

Tooth development is regulated by numerous genes and signaling pathways. Some studies suggest that mutations in these genes may be associated with several cancer types. However, the tooth agenesis mutated genes role in the prognosis and their clinical therapeutic potentials in pan-cancer have not been elaborately explored. Moreover, the intrinsic correlation between tooth agenesis and cancers also needs to be further verified. We preliminarily analyzed expression levels and prognostic values of causative genes of tooth agenesis, and explored the correlation between the expression of tooth agenesis mutated genes and TME, Stemness score, clinical characteristic, immune subtype, and drug sensitivity in pan-cancer, which based on updated public databases and integrated some bioinformatics analysis methods. In addition, we conducted the enrichment analysis of tooth agenesis mutant genes from KOBAS database. We observed that TA mutant genes had significant gene expression differences in multiple cancer types compared with normal tissues. The expression of causative genes of TA is associated with the prognosis in several cancers from different databases. For example, AXIN2 and MSX1 were correlated to the overall survival (OS) of uterine corpus endometrial carcinoma. PAX9 and TP63 were related to OS of lung squamous cell carcinoma. And TP63 was associated with OS in breast invasive carcinoma and pancreatic adenocarcinoma. Furthermore, the expression of TA mutant genes also has a significant correlation with stromal and immune scores, and RNA stemness score and DNA stemness score in pan-cancer. Besides, we observed that all causative genes of TA were significantly correlated with immune subtypes. Moreover, KEGG pathway analysis showed that causative genes of TA were associated with the development and progression of breast cancer, basal cell carcinoma, gastric cancer, and hepatocellular carcinoma. Finally, AXIN2 expression has a significantly positive or negative correlation with drug sensitivity. Our study indicates the great potential of TA mutant genes as biomarkers for prognosis and provides valuable strategies for further investigation of TA mutant genes as potential therapeutic targets in cancers. Our study can further verify that there may be an intrinsic correlation between tooth agenesis and the occurrence of multiple cancers.

Five-Year Follow-Up of a Child with Non-Syndromic Oligodontia from before the Primary Dentition Stage: A Case Report

BACKGROUND

Congenital absence of teeth is a major dental abnormality in pediatric dentistry and the absence of six or more teeth is defined as oligodontia. Few reports of patients with non-syndromic oligodontia without systemic disease have continued dental follow-up from an early age.

METHODS

We performed the five-year follow-up from before the eruption of the primary dentition of a Japanese child with non-syndromic oligodontia and analyzed changes in dental arch growth.

RESULTS

At the oral examination at the age of 1 year and 2 months, eight primary incisors were congenitally absent. Therefore, we made dentures for the patient at the age of 3 years and 4 months. From the age of 5 years and 1 month, the child received articulation training for dysarthria from a speech therapist to improve the function and appearance of the oral cavity. Measurement of the patient's dental models revealed a particularly narrow dental arch, especially between the primary canines.

CONCLUSIONS

Our findings highlight the importance of treatment for patients with non-syndromic oligodontia from an early age by multiple medical professionals, recognizing that the missing teeth affect the growth of the maxillofacial region.

Novel Candidate Genes for Non-Syndromic Tooth Agenesis Identified Using Targeted Next-Generation Sequencing

Non-syndromic tooth agenesis (ns-TA) is one of the most common dental anomalies characterized by the congenital absence of at least one permanent tooth (excluding third molars). Regarding the essential role of genetic factors in ns-TA aetiology, the present study aimed to identify novel pathogenic variants underlying hypodontia and oligodontia. In a group of 65 ns-TA patients and 127 healthy individuals from the genetically homogenous Polish population, the coding sequences of 423 candidate genes were screened using targeted next-generation sequencing. Pathogenic and likely pathogenic variants were identified in 37 (56.92%) patients, including eight nucleotide alternations of genes not previously implicated in ns-TA (CHD7, CREBBP, EVC, LEF1, ROR2, TBX22 and TP63). However, since only single variants were detected, future research is required to confirm and fully understand their role in the aetiology of ns-TA. Additionally, our results support the importance of already known ns-TA candidate genes (AXIN2, EDA, EDAR, IRF6, LAMA3, LRP6, MSX1, PAX9 and WNT10A) and provide additional evidence that ns-TA might be an oligogenic condition involving the cumulative effect of rare variants in two or more distinct genes.

Association between Smoking during Pregnancy and Short Root Anomaly in Offspring

Short root anomaly (SRA) is a dental anomaly with short dental roots and its pathogenesis is poorly understood. This study investigated the association between maternal smoking during pregnancy and SRA in offspring. A survey was conducted on 558 children aged 8–16 years from two public schools in Ulaanbaatar, Mongolia. SRA was diagnosed using cases with a root-crown ratio of maxillary central incisors of ≤1.0. A questionnaire survey was conducted to assess maternal lifestyle habits. Multiple logistic regression was used to analyse the association between maternal smoking during pregnancy and SRA in offspring after adjusting for possible confounders. The prevalence of SRA in these children was 14.2%. Children whose mothers smoked from pregnancy to date were found to be 4.95 times (95% confidence interval [CI]: 1.65–14.79) more likely to have SRA than those whose mothers never smoked, after adjusting for possible confounders. Additionally, children whose mothers had been exposed to passive smoking during pregnancy were found to be 1.86 times (95% CI: 1.02–3.40) more likely to have SRA than those whose mothers had not been exposed to passive smoke. Our population-based study suggests that maternal and passive smoking exposure during pregnancy can affect tooth root formation in children.

Role of Maternal Infections and Inflammatory Responses on Craniofacial Development

Pregnancy is a tightly regulated immunological state. Mild environmental perturbations can affect the developing fetus significantly. Infections can elicit severe immunological cascades in the mother's body as well as the developing fetus. Maternal infections and resulting inflammatory responses can mediate epigenetic changes in the fetal genome, depending on the developmental stage. The craniofacial development begins at the early stages of embryogenesis. In this review, we will discuss the immunology of pregnancy and its responsive mechanisms on maternal infections. Further, we will also discuss the epigenetic effects of pathogens, their metabolites and resulting inflammatory responses on the fetus with a special focus on craniofacial development. Understanding the pathophysiological mechanisms of infections and dysregulated inflammatory responses during prenatal development could provide better insights into the origins of craniofacial birth defects.

Association between tooth agenesis and cancer: a systematic review

The congenital absence of multiple teeth may share the same genetic background of the development of some types of cancer. Objective: This systematic review aimed to investigate the possible association between dental agenesis and cancer, and the perspective of agenesis as an early predictor for cancer risk. Methodology: The electronic databases PubMed, Scopus, Web of Science, Cochrane Library, LILACS, and OpenGrey were searched and the risk of bias was evaluated using the Newcastle-Ottawa tool. The GRADE tool was used to evaluate the certainty of the evidence. Results: Six studies met the eligibility criteria. A positive co-occurrence between ovarian cancer and hypodontia was found in two articles. Three studies evaluated the association between dental agenesis and colorectal cancer and only one showed common genes for these conditions. One paper found individuals with hypodontia had a higher risk of family history of cancer. Five studies had a fair quality and one a good quality. The certainty of evidence was classified as very low. Conclusion: Notwithstanding the limited scientific evidence, there may be a possible association between dental agenesis and cancer due to genes involved in both conditions. Agenesis of multiple teeth could be an early indicator of cancer risk. Nevertheless, studies with a better level of evidence are needed to confirm this possible association.

Consecutive tooth agenesis patterns in non-syndromic oligodontia

Agenesis of two or more consecutive adjacent permanent teeth (consecutive tooth agenesis, CTA) is a serious manifestation of oligodontia requiring long-term, multi-disciplinary treatment. Therefore, the present study investigated the characteristics of the CTA pattern in orthodontic patients with non-syndromic oligodontia. Using panoramic radiographs, the number of agenetic permanent teeth excluding third molars in non-syndromic orthodontic patients was evaluated, and patients with six or more agenetic teeth (oligodontia group, n = 97) and with one to five agenetic teeth (hypodontia group, n = 107) were selected. The numbers of CTA including third molars in each quadrant and in each patient were compared between the groups. Each quadrant with CTA of patients was categorized into one of the following four types: (I) involves anterior teeth only; (II) involves posterior teeth only; (IIIA) includes anterior and posterior teeth; and (IIIB) separate in the anterior and posterior teeth. CTA in at least one quadrant was found in 91.8 and 4.7% of patients in the oligodontia and hypodontia groups, respectively. The highest frequency CTA patterns included agenesis of the first and second premolars and of the second and third molars in the oligodontia and hypodontia groups, respectively. In the oligodontia group, type IIIA was significantly more frequent in the maxillary than in the mandibular quadrant. Most oligodontia patients who visit orthodontic clinics have CTA. A rare but severe CTA pattern that continues from the anterior to posterior segments is more frequent in the maxillary than in the mandibular quadrant.

Common variants of EDA are associated with non-syndromic hypodontia

OBJECTIVE

The aim of this case-control study was to investigate the association between non-syndromic hypodontia and nineteen common variants of candidate genes ectodysplasin A (EDA), paired box 9 (PAX9), msh homeobox 1 (MSX1) and axis inhibition protein 2 (AXIN2).

SETTINGS AND SAMPLE POPULATION

Sixty-one hypodontia cases were frequency-matched to 253 controls with no missing teeth (excluding the third molars).

MATERIAL AND METHODS

Self-report data and DNA samples were collected from each participant.

RESULTS

The sample had a mean age of 16.6 years (SD = 7.3), with most participants being female (59.6%), and of New Zealand European origin (75.4%). Using multiple logistic regression analysis, it was found that the T-allele of rs12853659 (EDA) and the G-allele of rs2428151 (EDA) were both associated with a higher risk of hypodontia (odds ratio, OR = 2.79, 95% CI = 1.11-7.01; and OR = 2.87, 95% CI = 1.04-7.94, respectively). The G-allele of rs2520378 (EDA) showed a protective effect with an OR of 0.61 (95% CI = 0.38-0.99). The EDA SNP findings were consistent with previous reports included in a meta-analysis. No associations were found with the PAX9, AXIN2 and MSX1 genes, after adjusting for sex and ethnicity.

CONCLUSIONS

Common variants of the EDA genes are associated with specific phenotypes of non-syndromic hypodontia, thus confirming their role in the regulatory pathways of normal tooth development. However, larger samples are needed to investigate the association further.

Maternal intake of caffeinated products and birth defects: a systematic review and meta-analysis of observational studies

Caffeinated products are frequently consumed by women of childbearing age worldwide. It still unclear that whether maternal intake of caffeine associated with an increased risk of birth defects. We searched the databases of PubMed, Embase, the Cochrane Library, and Web of Science for eligible studies through July 2020. All studies examining the association between maternal consumption of caffeine or caffeinated products and birth defects were included. Twenty-nine studies were included in this meta-analysis. Among all the birth defects, maternal caffeine consumption was associated with a higher risk of cardiovascular defects, [odds ratio (OR) 1.17; 95% confidence interval (CI), 1.07-1.28], craniofacial defects (OR 1.09; 95% CI, 1.02-1.17), alimentary tract defects (OR 1.35; 95% CI, 1.16-1.56), and abdominal-wall defects and hernia (OR 1.13; 95% CI, 1.03-1.25). No association was found between maternal caffeine intake and musculoskeletal system defects, genitourinary system defects, nervous system defects, or chromosomal abnormalities. Meanwhile, all three of the caffeine consumption categories (low, moderate, and high) were associated with a higher risk of cardiovascular defects and alimentary tract defects.

Association between Maternal Smoking during Pregnancy and Missing Teeth in Adolescents

Tooth agenesis and disturbance of tooth eruption is the most prevalent oral defect, and is possibly caused by the interaction of genetic and environmental factors. We hypothesized that prenatal factors may affect tooth development. The objective of this study was to examine whether smoking during pregnancy was associated with missing teeth in the offspring during adolescence. The study population comprised pregnant women and their children registered (N = 1052) at Koshu city, Japan. When the expectant mothers visited the city office for pregnancy registration, a survey was conducted to ascertain their lifestyle habits. Data on missing teeth in the children were obtained from the compulsory dental health checkup during junior high school years. Multivariate logistic regression models were fitted to assess the association between missing teeth and lifestyle habits. A total of 772 children were studied. The prevalence of missing teeth in these children was 4.9%. Children whose mothers smoked six cigarettes or more per day were 4.59 (95% CI: 1.07-19.67) times more likely to present with missing teeth than those children whose mothers did not smoke, after adjustment for possible confounders. Our findings indicate that smoking during pregnancy can be a risk factor for missing teeth in the offspring.

Etiology of Hypomineralized Second Primary Molars: A Prospective Twin Study

The etiology of hypomineralized second primary molars (HSPM) is unclear, but genetic and environmental factors have been proposed. The aim of this study was to investigate the relative contribution of genes and environment to the etiology of HSPM and to identify potential environmental risk factors in a longitudinal twin cohort. Children from twin pregnancies ( N = 250) were recruited antenatally, and detailed demographic, health, and phenotypic data were collected at recruitment, 24- and 36-wk gestation, birth, and 18 mo of age. 25-Hydroxyvitamin D was quantified for mothers at 28-wk gestation and infants at birth. Dental examinations were conducted on the twins at 6 y of age to determine the presence, severity, and extent of HSPM per standardized criteria. To investigate associations of environmental risk factors with HSPM, multiple logistic regression models were fitted with generalized estimating equations to adjust for twin correlation. Within- and between-pair analyses were performed for unshared continuous variables: birthweight and birth 25-hydroxyvitamin D. Twin-twin concordance for monozygotic (MZ) and dizygotic (DZ) pairs was calculated and compared after adjusting for identified risk factors. A total of 344 twins underwent the 6-y-old dental assessment; HSPM occurred in 68 (19.8%). After adjusting for potential confounders, vitamin D levels at birth, infantile eczema, dizygosity, in vitro fertilization, socioeconomic position, and maternal smoking beyond the first trimester of pregnancy demonstrated the strongest associations with HSPM. Overall concordance for HSPM was 0.47 (95% CI, 0.32 to 0.62) with weak evidence ( P = 0.078) of higher concordance in MZ twins (0.63; 95% CI, 0.38 to 0.89) as compared with DZ twins (0.41; 95% CI, 0.24 to 0.58). After adjusting for known risk factors, there was no evidence ( P = 0.172) for an additive genetic influence. These findings suggest that shared and unshared environmental factors, such as maternal smoking later in pregnancy and infantile eczema, are important in the etiology of HSPM.

Association between DNA methylation in cord blood and maternal smoking: The Hokkaido Study on Environment and Children's Health

Maternal smoking is reported to cause adverse effects on the health of the unborn child, the underlying mechanism for which is thought to involve alterations in DNA methylation. We examined the effects of maternal smoking on DNA methylation in cord blood, in 247 mother–infant pairs in the Sapporo cohort of the Hokkaido Study, using the Infinium HumanMethylation 450K BeadChip. We first identified differentially methylated CpG sites with a false discovery rate (FDR) of <0.05 and the magnitude of DNA methylation changes (|β| >0.02) from the pairwise comparisons of never-smokers (Ne-S), sustained-smokers (Su-S), and stopped-smokers (St-S). Subsequently, secondary comparisons between St-S and Su-S revealed nine common sites that mapped to ACSM3, AHRR, CYP1A1, GFI1, SHANK2, TRIM36, and the intergenic region between ANKRD9 and RCOR1 in Ne-S vs. Su-S, and one common CpG site mapping to EVC2 in Ne-S vs. St-S. Further, we verified these CpG sites and examined neighbouring sites using bisulfite next-generation sequencing, except for AHRR cg21161138. These changes in DNA methylation implicate the effect of smoking cessation. Our findings add to the current knowledge of the association between DNA methylation and maternal smoking and suggest future studies for clarifying this relationship in disease development.

Maternal smoking during pregnancy is associated with offspring hypodontia

'...maternal smoking during pregnancy is a risk factor for having a child with hypodontia.'