No genetic causal association between periodontitis and ankylosing spondylitis: a bidirectional two-sample mendelian randomization analysis.

BACKGROUND: Observational studies that reveal an association between periodontitis (PD) and ankylosing spondylitis (AS) exist. However, observational research is prone to reverse causality and confounding factors, which make it challenging to infer cause-and-effect relationships. We conducted a two-sample Mendelian randomization (MR) study to examine the causal relationship between the genetic prediction of PD and AS. METHODS: In our study, single-nucleotide polymorphisms (SNPs) were defined as instrumental variables (IVs). The genetic association with PD came from the Gene-Lifestyle Interactions and Dental Endpoints (GLIDE) consortium, wherein 17353 cases of European ancestry and 28210 controls of European ancestry were included in this study. The genetic association with AS from the Neale Laboratory Consortium included 337,159 individuals from the United Kingdom, with 968 cases and 336,191 controls. MR analysis was mainly performed using the inverse-variance weighted (IVW) method. In addition, the robustness of the study findings was assessed using sensitivity, pleiotropy, and heterogeneity analyses. RESULTS: Eighteen independent SNPs with P-values significantly smaller than 1 × 10- 5 were used as IV SNPs for PD, while 39 independent SNPs with P-values significantly smaller than 1 × 10- 5 were used as IV SNPs for AS. The results of the IVW method revealed no causal association between PD and AS (odds ratio = 1.00, 95% confidence interval: 0.99953 to 1.00067, P = 0.72). The MR-Egger method did not support the causal association between PD and AS. It is unlikely that horizontal pleiotropy distorts causal estimates based on sensitivity analysis. No significant heterogeneity was observed in the Q test. The ''leave-one-out'' analysis demonstrated that the robustness of our results was unaffected by eliminating any of the IVs. Likewise, no significant causative effect for AS on PD was observed in the inverse MR analysis. CONCLUSIONS: The study results do not support shared heritability or a causal association between PD and AS.

Deciphering genetic causality between inflammatory bowel disease and periodontitis through bi-directional two-sample Mendelian randomization.

Inflammatory bowel disease (IBD) and periodontitis are reported to be closely associated; however, whether there is a causal association between them remains unclear. To explore the existence of this causality, this study applied a bidirectional two-sample Mendelian randomization (MR). The genetic variants were obtained from the summary statistics of genome-wide association studies of IBD, including its subtypes CD and UC, and periodontitis. 175, 148, 113, and six single-nucleotide polymorphisms were selected as instrumental variables for IBD, CD, UC, and periodontitis, respectively. In MR analysis, random-effects inverse-variance weighted was used as the primary method, and weighted median and MR Egger regression were applied as the complementary method. A series of sensitivity analyses were also conducted to ensure the reliability of the results. None of these analyses found a significant effect of genetically proxied IBD and its subtypes on periodontitis, and vice versa. Subsequent sensitivity analyses did not detect any horizontal pleiotropy and heterogeneity. Caution should be exerted when it comes to clinical relevance and further studies are needed to clarify the relationship between IBD and periodontitis.

The underlying molecular mechanisms and biomarkers between periodontitis and COVID-19.

OBJECTIVE: Emerging evidence shows the clinical consequences of patient with COVID-19 and periodontitis are not promising, and periodontitis is a risk factor. Periodontitis and COVID-19 probably have a relationship. Hence, this study aimed to identify the common molecular mechanism that may help to devise potential therapeutic strategies in the future. MATERIAL AND METHODS: We analyzed two RNA-seq datasets for differential expressed genes, enrichment of biological processes, transcription factors (TFs) and deconvolution-based immune cell types in periodontitis, COVID-19 and healthy controls. Relationships between TFs and mRNA were established by Pearson correlation analysis, and the common TFs-mRNA regulatory network and nine co-upregulated TFs of the two diseases was obtained. The RT-PCR detected the TFs. RESULTS: A total of 1616 and 10201 differentially expressed gene (DEGs) from periodontitis and COVID-19 are found. Moreover, nine shared TFs and common biological processes associated with lymphocyte activation involved in immune response were identified across periodontitis and COVID-19. The cell type enrichment revealed elevated plasma cells among two diseases. The RT-PCR further confirmed the nine TFs up-regulation in periodontitis. CONCLUSION: The pathogenesis of periodontitis and COVID-19 is closely related to the expression of TFs and lymphocyte activation, which can provide potential targets for treatment.

Immediate Implant Placement With or Without Immediate Provisionalization in the Maxillary Esthetic Zone: A Systematic Review and Meta-analysis.

PURPOSE: To determine whether immediate implant placement and loading renders different outcomes from delayed loading with respect to midfacial mucosal level in the maxillary esthetic area. MATERIALS AND METHODS: A literature search was conducted in four electronic databases (PubMed, Web of Science, Embase, and Cochrane), identifying eligible clinical studies published prior to December 2021. Only randomized controlled trials (RCTs) comparing immediate implant placement with or without immediate loading in the maxillary esthetic zone with a mean follow-up of at least 12 months were selected for qualitative analysis and meta-analysis. The Cochrane Risk of Bias tool was adopted to assess the quality of the evidence. The heterogeneity between the pooled literature was analyzed through the chi-square test (P < .05) and quantified by the I2 index. A mixed-effects model was applied if it appeared that there was noteworthy heterogeneity; otherwise, a random-effects model was chosen. For continuous outcomes, the estimate of relative effect was presented to display the standardized mean differences (SMDs) and 95% CIs. For dichotomous variables, the Mantel-Haenszel statistical method was applied with effect sizes expressed as risk ratios (RRs) and 95% CIs. This study is registered on PROSPERO with number CRD42017078611. RESULTS: Out of 5,553 records, 8 RCTs were involved, providing data for 324 immediately placed implants (immediate implants subjected to immediate loading [IPIL]: 163; immediate implants subjected to delayed loading [IPDL]: 161) that had been in function within 12 to 60 months. Meta-analyses revealed significantly lower midfacial mucosal level changes for IPIL compared with IPDL, pointing to 0.48 mm (95% CI: -0.84 to -0.12; P = .01), as well as more significant papillary recession after IPDL (SMD -0.16; 95% CI: -0.31 to 0.00; P = .04). The differences regarding implant survival and marginal bone loss between the two loading groups showed no statistical significance. The result of metaanalyses revealed similar plaque score (SMD 0.03; 95% CI: -0.22 to 0.29; P = .79) and probing depth (SMD -0.09; 95% CI: -0.23 to 0.05; P = .21) for IPIL and IPDL. On the other hand, IPIL induced a trend toward more bleeding on probing (SMD 0.22; 95% CI: 0.01 to 0.42; P = .04) and less change in facial ridge dimension (SMD 0.94; 95% CI: -1.49 to -0.39; P < .01). CONCLUSION: After a follow-up ranging from 12 to 60 months, midfacial mucosa level change was 0.48 mm lower following IPIL compared with IPDL. Immediate implant placement and loading is conducive to the preservation of physiologic soft and hard tissue architecture, appearing to offer considerable benefits in the anterior zone. In summary, IPIL should be considered in the esthetic zone if the primary implant stability permits. Int J Oral Maxillofac Implants 2023;38:422-434. doi: 10.11607/jomi.10112.

The relationship between labial soft tissue changes and jumping spaces after immediate implant placement and restoration in the anterior maxilla: A prospective study.

Oral implants have been increasingly used in the treatment of edentulous patients or those with dentition defects due to reliable treatment procedure and favorable long-term prognosis. We investigated the changes of labial soft tissue contours with different jumping spaces after immediate implant placement and restoration (IIPR) in the maxillary esthetic area and also provided a long-term stability measurement for the changing trend of soft tissue contour. All patients had been separated into three groups based on the jumping space: group A (horizontal defect dimension [HDD] 2 mm), group B (2 mm < HDD 3 mm), and group C (HDD > 3 mm) and the digital impressions were obtained in the first, third, and sixth month after the operation. The changes of gingival mucosa levels, the average thickness of soft tissue contour volume, and the linear change of submarginal level decreased gradually across the three groups, with the largest change of submarginal level being at 5mm. The size of the jumping space was moderately negatively correlated with the level and average thickness of gingival mucosa and the linear changes of 3 mm and 5 mm under gingival margin, while there was no significant correlation with pink esthetic score (PES) and the linear change of the 1 mm under the gingival margin. Generally, IIPR of upper anterior teeth can achieve esthetic satisfaction, and the level of soft tissue around the implant can be well preserved.