Hypothyrodism as a risk factor of periodontitis and its relation with vitamin D deficiency: mini-review of literature and a case report

Transcriptomic Analysis Reveals Genetic Cross-Talk between Periodontitis and Hypothyroidism

Background. Aim of this bioinformatics study based on transcriptomic analysis was to reveal the cross-talk between periodontitis (PD) and hypothyroidism (HT). Methods. The gene expression datasets GSE18152 and GSE176153 of HT and GSE10334, GSE16134, and GSE173078 of PD were downloaded through the Gene Expression Omnibus (GEO) database. Differential Expression Genes (DEG) between cases and controls in each microarray were assessed by using the “limma” (linear models for microarray data) R package (|log2 fold change (FC)| >0 and $P$ -value <0.05). To analyze the cross-talk effect between HT and PD, the intersection of DEG of HT and PD was selected. To investigate the biological function of cross-talk genes, the gene ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were applied. Protein-Protein Interaction (PPI) network was constructed using Cytoscape software. Top 10 cross-talk genes were screened, and the expression values of these 10 genes were extracted. ROC analysis was performed by using the pROC package and GGplot2 package of R language to predict the classification accuracy. Results. The overlapping DEG between HT and PD were 107 cross-talk genes. The results revealed that developmental process ( $P$ -value =1.06E-21) was the most significantly enriched biological process, followed by cell differentiation ( $P$ -value =8.49E-18) and immune system process ( $P$ -value =6.78E-11). KEGG analysis showed that Complement and coagulation cascades ( $P$ -value =2.29E-05), Hematopoietic cell lineage ( $P$ -value =2.66E-05), Phospholipase D signaling pathway ( $P$ -value =0.034367878) and Chemokine signaling pathway ( $P$ -value =0.04946333) were significantly enriched. The top 10 genes with most connections were LCE1B, LCE2B, LCE2A, LCE2C, LCE1C, LCE1F, ITGAM, C1QB, TREM2, and CD19. The AUC values of the two datasets of HT were both greater than 65% (GSE18152 = 81.42%, GSE176153 = 68.75%). AUC values of three datasets of PD were all greater than 60% (GSE10334 = 69.23%, GSE16134 = 73.72%, GSE173078 = 81.6%). Conclusions. A genetic cross-talk between HT and PD was detected, whereby LCE family genes appeared to play the most important role.

Relationship between hypothyroidism and periodontitis: A scoping review

AIM

The objective of this study was to assess the existing literature to determine if a relationship exists between hypothyroidism and periodontitis.

METHODS

We used a modified approach to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses by searching five databases in addition to the gray literature. Keywords in the title and abstract fields, as well as subject headings for both periodontal disease and hypothyroidism, were used to search the existing literature for publications relevant to evaluation of the thyroid-periodontitis relationship.

RESULTS

The authors screened 847 unique publications which, after applying inclusion and exclusion criteria, yielded 29 publications, which were further analyzed for relevance and applicability. Most of the included papers were cross-sectional studies and retrospective chart reviews. Following critical analysis, four publications, including one abstract, were used to further assess the hypothyroid-periodontitis relationship.

CONCLUSIONS

There are very few high-quality studies describing the potential association between hypothyroidism and periodontitis. In general, and among the included papers with the fewest confounding factors, a positive relationship between hypothyroidism and periodontitis was found. Further well-controlled, prospective clinical and immunologic studies will be required to confirm that relationship.

The Qualitative and Quantitative Structure of Oral Microbiocenosis in Rats with Periodontitis in a Setting of Hyper- and Hypothyroidism

Background and aims. Oral microbial flora is a highly sensitive indicator system producing qualitative and quantitative responses to changes in various individual organs and systems. The aim of study was to perform a comparative analysis of qualitative and quantitative structure of oral microbiocenosis in rats with comorbidity-free periodontitis and in animals with periodontitis in a setting of hyper- and hypothyroidism.

Material and methods. Experimental studies were conducted on 48 mature male white rats. Samples for microbiological tests were taken from dental surfaces (on the border between hard tissue and gums in the interdental spaces). The isolated pure cultures were identified by their morphological, tinctorial, cultural and biochemical properties and the signs of pathogenecity.

Results. We found that the oral dysbiosis occurring in a setting of periodontitis in rats is chiefly characterized by increased quantity of coccal forms and by increased candidal inoculation; these organisms cumulatively inhibit the growth of normal microbial flora, such as Lactobacilli, bacteroids and Bifidobacteria. Thyroid dysfunction exacerbates changes in the qualitative and quantitative structure of oral microbiocenosis.

Conclusions. The periodontitis in a setting of thyroid dysfunction increases both the species variety and the quantitative counts of oral microbial flora, with predominance of such microbial organisms as Staph. aureus, E. coli, E. faecalis, Candida albicans and P. aeruginosa.

Association between obstructive sleep apnea and comorbidities with periodontal disease in adults

Background:

Several studies have reported an association between periodontal disease and obstructive sleep apnea (OSA). However, heterogeneity of results suggests that there is insufficient evidence to support this association.

Aims:

The objective of this study was to identify the association between periodontal disease and OSA in adults with different comorbidities.

Settings and Design:

One hundred and ninety-nine individuals (107 women and 92 men) underwent polysomnography with a mean age of 49.9 years were recruited.

Materials and Methods:

The presence of OSA, comorbidities, and periodontal disease was evaluated in each individual. Student's t-tests or Chi-square and ANOVA tests were used to determine the differences between groups.

Results:

The prevalence of periodontal disease was 62.3% and 34.1% for gingivitis. The results showed no statistically significant association between all groups of patients with OSA and non-OSA patients for gingivitis (P = 0.27) and for periodontitis (P = 0.312). However, statistically significant association was shown between periodontitis and mild OSA compared with the periodontitis and non-OSA referent (P = 0.041; odds ratio: 1.37 and 95% confidence interval 1.11–2.68). The analysis between OSA and comorbidities showed a statistically significant difference for patients with OSA and hypertension (P < 0.001) and for patients with OSA and hypertensive cardiomyopathy (P < 0.001) compared with healthy individuals. Periodontitis was more likely in men with severe OSA and with any of two comorbidities such as hypertension or hypertensive cardiomyopathy. Women with hypertension or hypertensive cardiomyopathy were more likely to have mild OSA, and these associations were statistically significant (P < 0.05).

Conclusions:

This study identified association between periodontitis and mild OSA and this association was more frequent in women with hypertension or hypertensive cardiomyopathy. Periodontitis was associated with severe OSA in men who showed any of two comorbidities such as hypertension or hypertensive cardiomyopathy.