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