Association between single-nucleotide polymorphisms in serotonin receptor 2A and melatonin receptor 1A genes and pain after root canal treatment.

AIM: This study aimed to investigate whether single-nucleotide polymorphisms (SNPs) in the genes encoding 5-HTR2A (5-Hydroxytryptamine (serotonin) receptor 2A) and MTNR1A (melatonin receptor 1A) may contribute to postoperative pain perception after root canal treatment. We hypothesised that SNPs in HTR2A and MTNR1A genes were associated with postoperative pain after root canal treatment. METHODOLOGY: This genetic cohort study enrolled patients with single-rooted teeth diagnosed with pulp necrosis and asymptomatic apical periodontitis before root canal treatment. Root canal treatment was performed in one session using a standardized protocol. Postoperative pain and tenderness were assessed using a visual analogue scale (recorded every day for 7 days and on the 14th and 30th days after root canal treatment). Genomic DNA was extracted from saliva and used to genotype the SNPs in HTR2A (rs4941573 and rs6313) and MTNR1A (rs6553010, rs6847693 and rs13140012) using real-time polymerase chain reaction. Genotypes were compared using univariate and multivariate Poisson regression with generalized estimating equations (p < .05). RESULTS: In total, 108 patients were enrolled in this study. The SNPs rs6553010 (MTNR1A), rs4941573 and rs6313 (HTR2A) were associated with an increased risk of developing pain after root canal treatment (p < .05). CONCLUSIONS: This study suggests that SNPs in HTR2A and MTNR1A influence pain response after root canal treatment.

Association between genetic polymorphisms in the melatonin receptor type 1 A gene and sleep bruxism.

OBJECTIVE: This study evaluated whether single nucleotide polymorphisms in the melatonin receptor type 1 A gene are associated with sleep bruxism in a Brazilian population. DESIGN: Individuals with suspected sleep-related problems were evaluated using polysomnography, following the recommendations proposed by the American Academy of Sleep Medicine and the Research Diagnostic Criteria for Temporomandibular Disorders. Deoxyribonucleic acid (DNA) samples were collected, and three single nucleotide polymorphisms in the melatonin receptor type 1 A gene (rs13140012, rs6553010, and rs6847693) were selected and genotyped using real-time polymerase chain reaction (RT-PCR). Chi-square and odds ratio tests were used to analyze genotypes and alleles individually, while using the plink software for haplotypes. A confidence interval of 95% was considered, and statistical significance was set at p < 0.05. RESULTS: This study included 48 individuals aged between 21 and 80 years, with 27 males and 21 females. From this sample, 17 individuals were diagnosed with sleep bruxism and 31 without bruxism. No associations were found between sleep bruxism and single nucleotide polymorphisms in either the genotypic, allelic, dominant, or recessive models (p > 0.05). Haplotype genetic analysis also did not reveal any association between single nucleotide polymorphisms and sleep bruxism (p > 0.05). CONCLUSION: The genetic polymorphisms rs6553010, rs13140012, and rs6847693 were not associated with sleep bruxism in the studied population.

Is there an association of genetic polymorphisms of the catechol-O-methyltransferase gene (rs165656 and rs174675) and the 5-hydroxytryptamine receptor 2A gene (rs4941573 and rs6313) with sleep bruxism in individuals with obstructive sleep apnea?

OBJECTIVE: To evaluate the association of single-nucleotide polymorphisms within the catechol-O-methyltransferase and 5-hydroxytryptamine receptor 2A genes with sleep bruxism in individuals diagnosed with obstructive sleep apnea. DESIGN: Sixty-nine individuals with suspected sleep-related problems were evaluated by polysomnography, following the recommendations of the American Academy of Sleep Medicine. Deoxyribonucleic acid (DNA) samples were collected only from 48 of the study participants because of missing polysomnographic data. DNA samples were collected and two single-nucleotide polymorphisms in the 5-hydroxytryptamine receptor 2A encoding HTR2A gene (rs4941573 and rs6313) and two in the catechol-O-methyltransferase gene (rs165656 and rs174675) were selected to be genotyped using real-time polymerase chain reaction. The association between sleep bruxism and genetic polymorphisms was investigated by recessive and dominant models. Association analyses were performed using a 95% confidence interval and the level of statistical significance was p < 0.05. RESULTS: From the 69 study participants, 48 were included in the polymorphism analysis and sleep bruxism was present in 35.4%. No significant differences were observed in the dominant and recessive models (p > 0.05). Haplotype and diplotype analyses revealed the predicted four haplotypes and two diplotypes were not associated with sleep bruxism. CONCLUSION: Polymorphisms rs174675 and rs165656 in the catechol-O-methyltransferase gene and rs4941573 and rs6313 in the 5-hydroxytryptamine receptor 2A gene were not significantly associated with sleep bruxism in individuals with obstructive sleep apnea.