Dental pain report in children and genetic polymorphism (rs4818) in Catechol-O-Methyltransferase (COMT) gene: a cross- sectional study

AIM

Polymorphisms in the COMT gene can alter enzymatic functions, raising levels of endogenous catecholamines, which stimulates beta-adrenergic receptors related to pain. This study aimed to evaluate whether a polymorphism in the COMT gene (rs4818) is associated with dental pain in children.

METHODOLOGY

A cross-sectional study was conducted with a representative sample of 731 pairs of children and parents randomly selected from a population-based sample of eight-year-old children. Reports of dental pain was evaluated using a question directed at the parents and self-reported pain using the Faces Pain Scale - Revised. Dental caries experience was determined using the Decayed, Missing, and Filled Teeth (DMFT) index. For genetic analysis, DNA was obtained from oral mucosa epithelial cells of 352 children randomly selected from the initial sample.

RESULTS

Children with the CC genotype had higher odds of reporting moderate to intense pain than those with the GG genotype (OR=3.60; 95% CI=0.80-16.20; p=0.03). These same children had greater odds of parental reports of pain (OR=1.93; 95% CI=0.91-4.08; p=0.02). Moreover, lower schooling of parents/guardians and caries experience in the primary dentition were significantly associated with greater odds of a parental report of dental pain (OR=2.06; 95% CI=1.47-2.91; p<0.001; OR=6.26; 95% CI=4.46-8.78; p<0.001).

CONCLUSIONS

The rs4818 polymorphism of the COMT gene is associated with dental pain. Children with the C allele are more likely to report higher levels of pain. Clinical Relevance: Even though the experience of pain is subjective and multifactorial, this study raises the hypothesis that there is a genetic predisposition to dental pain that should be considered in clinical practice.

Interaction Between Environmental Factors and Polymorphisms in a Hypoxia-Related Gene (HIF-1) Associated with Hypomineralized Second Primary Molars

Purpose: This study's purpose was to investigate whether polymorphisms in the HIF-1 encoding gene and hypoxia-related environmental factors were associated with hypomineralized second primary molars (HSPMs). Methods: From a total of 731 children from Curitiba, Paraná, Brazil, were selected, the prevalence of HSPMs in this population was 9.4 percent, representing 69 cases (HSPMs) and 662 controls. The environmental factors were collected via questionnaire. HSPMs were evaluated by calibrated examiners. Two genetic polymorphisms (rs2301113 and rs2057482) in the HIF-1 gene were genotyped by polymerase chain reaction in real time. Associations were tested by Poisson regression analysis (Prevalence Ratio_adjusted; P<0.05). Results: In the multiple variable model, including the environmental factors and genetic polymorphisms, maternal use of an illicit drug (Prevalence Ratio_adjusted; equals 4.52; P<0.001; 95 percent confidence interval [95% CI] equals 2.38-8.53), maternal diseases during pregnancy (Prevalence Ratio_adjusted; equals 1.97; P=0.034; 95% CI equals 1.05 to 3.71), and respiratory diseases during childhood (Prevalence Ratio_adjusted; equals 2.66; P=0.003; 95% CI equals 1.41 to 5.03) increased significantly the prevalence of HSPMs. In the presence of environmental factors, individuals carrying at least one C allele in rs2057482 had a lower prevalence of HSPMs (Prevalence Ratio_adjusted; equals 0.51; P=0.048; 95% CI equals 0.27 to 0.99). Conclusions: Children who had hypoxia-related factors presented with a higher prevalence of hypomineralized second primary molars. A C allele in rs2057482 served as protection against HSPMs in hypoxia conditions.

The relationship between molar incisor hypomineralization, dental caries, socioeconomic factors, and polymorphisms in the vitamin D receptor gene: a population-based study

OBJECTIVES

The purpose of this cross-sectional study was to investigate whether polymorphisms in vitamin D receptor (VDR) genes increase the prevalence of dental caries, molar incisor hypomineralization (MIH), and hypomineralized primary second molars (HPSM).

MATERIAL AND METHODS

A representative population-based sample of 731 schoolchildren, 8 years of age, was randomly selected in Curitiba, Paraná, Brazil. MIH, HPSM, and dental caries were clinically assessed by four calibrated examiners (kappa > 0.80) using European Academy of Pediatric Dentistry (2003) criteria, the modified Developmental Defects of Enamel (DDE) index, and the Decayed, Missing, or Filled Teeth (DMFT) index by the World Health Organization (2013), respectively. The VDR rs739837 and rs2228570 polymorphisms were genotyped using real-time polymerase chain reaction. Associations were analyzed by Poisson regression with robust variance (α = 0.05).

RESULTS

Schoolchildren with MIH presented a higher prevalence of dental caries (DMFT > 1, PR = 2.52, confidence interval = 1.60-3.97, p ≤ 0.001). No association was observed between MIH, HPSM, and dental caries, with rs739837 and rs2228570 polymorphisms. Individuals with the GT/GG genotype in rs739837 polymorphism presented a higher prevalence of MIH in molars and incisors than individuals TT (PR = 2.34, confidence interval = 1.08-5.07, p = 0.03).

CONCLUSION

Children with MIH presented a significant higher prevalence of dental caries than children without MIH. To carry at least one G allele in rs739837 was associated to higher prevalence of MIH in molars and incisors.

CLINICAL RELEVANCE

Our findings suggested that more severe cases with incisors affected by MIH could be associated with polymorphism in VDR gene.

Demarcated opacity in primary teeth increases the prevalence of molar incisor hypomineralization

This cross-sectional study aimed to assess the prevalence of molar incisor hypomineralization (MIH) and its relationship with the number of primary teeth with developmental defects of enamel (DDE). A representative population-based sample of 731 schoolchildren was randomly selected from the public school system in Curitiba, Brazil. Schoolchildren aged 8 years with fully erupted permanent first molars and incisors were eligible for the study. MIH and DDE were classified by four calibrated examiners (kappa > 0.75) according to EAPD criteria and to the FDI-modified DDE index. Clinical data were collected in a school environment. Socioeconomic information was collected through a self-administered semistructured questionnaire applied to the children's caregivers. Statistical analyses were carried out using Poisson multiple regression with robust variance (α = 0.05). MIH prevalence was 12.1% (95%CI: 10-15), and opacities were the most prevalent defect. Socioeconomic factors were not associated with MIH. Children with demarcated opacity in primary teeth presented a higher prevalence of MIH than those without DDE in primary teeth. In the multiple analysis, the increase of one primary tooth affected by demarcated opacity increased the prevalence of MIH by 33% (PR = 1.33, 95%CI: 1.15-1.53, p < 0.001). Asian children had a higher prevalence of MIH (PR = 2.91, 95%CI: 1.08-8.09 p = 0.035) than did Caucasian children.Conclusion: Based on these findings, the prevalence of MIH in Curitiba was 12.1%. Demarcated opacity in primary teeth could be considered a predictor of MIH.