Background/Objectives: Bitter Taste Receptors (encoded by TAS2R genes) are expressed in mucosal and bronchial epithelia, as well as in immune cells, contributing to defense against airborne pathogens such as SARS-CoV-2. Data on single-nucleotide polymorphisms (SNPs) in TAS2R genes or pseudogenes in COVID-19 are limited. This study examined the association between TAS2R SNPs and COVID-19 infection and seroconversion in European individuals participating in the Canadian Longitudinal Study on Aging. Methods: Data from the Genome-wide Genetic Data, Comprehensive Baseline (version 7.0), Follow-up 2 (version 1.1), COVID-19 Questionnaire Study (4-2020 to 12-2020), and COVID-19 Seroprevalence (Antibody) Study (11-2020 to 7-2021) datasets were accessed. Associations of TAS2R SNPS with COVID-19 infection or seroconversion were determined using logistic regression adjusted for sociodemographics, genetic principal components, smoking, vaccine doses, and chronic medical conditions (diabetes, immune-mediated inflammatory diseases (IMIDs), respiratory disease, and cardiovascular disease). Results: In the COVID-19 Questionnaire Study (N = 14,073), the rs117458236 (C) variant in TAS2R20 showed a trend toward an association with COVID-19 infection (OR = 1.95; 95% Confidence Interval (CI): 0.98, 3.51). In the COVID-19 Antibody Study (N = 8313), the rs2234235(G) variant in TAS2R1 was associated with anti-nucleocapsid (OR = 1.55; CI: 1.06, 2.20) and anti-spike response (OR = 0.74; CI: 0.57, 0.98); the rs2234010(A) variant in TAS2R5 was associated with anti-nucleocapsid (OR = 1.56; CI: 1.08, 2.19); and the rs34039200(A) variant in TAS2R62P was associated with anti-spike (OR = 0.86; CI: 0.77, 0.97). In a subgroup analysis, the rs2234235(G) variant in TAS2R1 was associated with a decreased anti-spike response to infection or vaccination in individuals with IMIDs or respiratory disease and an increased risk of SARS-CoV-2 infection. Conclusions: TAS2R variants are associated with COVID-19 infection and vaccine response. These data may inform personalized management and vaccination strategies.

This study examined whether the degree of abutment surface modification that may occur with regular periodontal instrumentation has a clinical impact in terms of increased plaque accumulation and increased peri-implant tissue inflammation on zirconia implant abutments. Thirteen patients who had zirconia implant crowns were recruited in this randomized clinical trial. Each patient acted as their control and had either the buccal or lingual surface of their screw-retained implant restoration scaled with a metallic scaler and the other surface with a non-metallic scaler at 3, 6, 9, and 12 months. Cytokine testing of the peri-implant crevicular fluid was completed at 0, 3, and 12 months for IL-2, IL-4, IL-6, IL-8, IL-10, TNF-α, or IFNγ. Implant crowns were removed at 12 months and evaluated under an atomic force microscope for the average roughness (Ra). The implant crowns were polished and re-inserted. The results were analyzed using the Kruskal–Wallis test, and post hoc tests were conducted with a significance level of α = 0.05. Significant differences in surface roughness (Ra) were observed between the metallic and non-metallic scalers. The median Ra values were 274.0 nm for metallic scalers and 147.1 nm for non-metallic scalers. However, there were no significant differences between the type of scaler used and the amount of clinical inflammation or cytokine production. Metallic scalers produced deeper, more aggressive surface alterations to the abutment/crown zirconia surface, but there was no statistically significant difference between the degree of surface alterations, amount of BOP, and the amplitude of cytokine inflammation produced.

Bitter taste receptors (T2Rs) contribute to innate immune responses and taste preferences. Variants in T2R genes (TAS2Rs) may increase the risk of adverse oral health. This study investigated the association of single nucleotide polymorphisms (SNPs) in 25 TAS2R genes and 12 TAS2R pseudogenes with oral health symptoms within the Canadian Longitudinal Study on Aging (CLSA) cohort. Allele frequencies were calculated using PLINK and compared with the 1000 Genomes Project for individuals of European descent. Associations of oral health symptoms reported by 21,991 individuals (mean age 63 years, 50% female, 48% never smokers), with TAS2R SNPs (87 in TAS2R genes; 37 in TAS2R pseudogenes; minor allele frequency > 0.01) were tested by Chi-square with Bonferroni correction and by logistic regression correcting for sociodemographic variables and oral health habits. Fifteen SNPs in TAS2R8, 9, 13, 14, 20, and 50 showed modest suggestive associations with self-reported sore jaw muscles. These variants were associated with relatively small changes in the odds of reporting sore jaw muscles (6 positive; 9 negative). Nine of these SNPs were in TAS2R20 and highly correlated (r² ≈ 1), likely representing a single locus-level genetic signal. However, none of the associations remained significant after Benjamini–Hochberg FDR correction across all 2604 SNP–phenotype tests, and these findings should therefore be considered exploratory. Structure-function analysis identified selected TAS2R20 residues near the predicted ligand-binding region, providing hypotheses for future functional investigation. These exploratory findings provide hypotheses for future genetic and functional investigation and require independent replication in clinically characterized cohorts.