Association of vitamin D levels and oral lichen planus. Systematic review and meta-analysis.

BACKGROUND: Oral lichen planus (OLP) is an inmuno-mediated mucocutaneous chronical inflammatory disease. Multiple predisposing factors are considered, such as autoimmune response, microorganisms, medications, dental materials, psychological stress, genetic predisposition or nutritional deficiencies. The deficiency of vitamin D has been related to various autoimmune diseases like OLP. MATERIAL AND METHODS: The electronic search was conducted in the MEDLINE (Pubmed), Scopus, Cochrane Library and Web of Science databases. To assess any potential risk of bias, the authors critically appraised each study by the Newcastle-Ottawa Scale for cohort and case-control studies. Pooled analyses were performed using a random-effects model. Heterogeneity of the studies was assessed by the I2 statistics. Forest Plots were performed to graphically represent the difference between vitamin D concentrations in the OLP compared to healthy group, with a 95% confidence interval. RESULTS: After applying our inclusion and exclusion criteria, 7 articles were included in our review. The median concentration vitamin D in ng/ml found in serum for patients with OLP was of 26,6311,75ng/ml and for healthy patients was of 31,438,7ng/ml. Regarding the quantitative analysis, 7 studies were included. The difference in the concentration of vitamin D in healthy patients and patients with OLP statistically significant (Weighted Mean Difference (WMD): -6.20, 95% CI: -11.24 to -1.15, p=0.02 and I2 heterogeneity: 94%, p<0.00001). CONCLUSIONS: The patients with OLP have statistically lower vitamin D levels than healthy patients.

Role of thyroid hormones in burning mouth syndrome. Systematic review.

BACKGROUND: Burning mouth syndrome is an idiopathic condition characterized by burning pain in a normal-appearing oral mucosa lasting at least four to six months. In the case of secondary burning mouth syndrome is associated with local or systemic factors (such as thyroid disorders) that can cause these symptoms. The aim of this review was to study the relationship between thyroid disorders and burning mouth syndrome. MATERIAL AND METHODS: The present study followed the PRISMA guidelines. An electronic search strategy was developed for PubMed/Medline, Scopus and Cochrane. The following combination of keywords and Boolean operators were used: Thyroid AND burning mouth; Thyroid AND burning mouth syndrome; Hypothyroidism AND burning mouth; Hypothyroidism AND burning mouth syndrome; Hyperthyroidism AND burning mouth; Hyperthyroidism AND burning mouth syndrome. The results were processed by existing free software in https://www.graphpad.com/. To evaluate the association of the categorical variables we used the Fisher test at a level of significance of p-value ≤ 0,05. As a primary summary measure the Odds Ratio (OR) has been used. To analyze the risk of bias the guidelines of the GRADE guide were used and the grade of evidence was analyzed by the guide of Joanna Briggs Institute: Levels of Evidence and Grades of Recommendations. RESULTS: After applying the inclusion and exclusion criteria, 5 studies were selected for review. The Chi-square was 10.92 and the Odds Ratio was 3.31 with respect to TSH values with p <0.0001 (Fisher's test). The population of patients with TSH alterations is increased in 80.49% and decreased in 19.51%. CONCLUSIONS: It can be concluded that thyroid hormone abnormalities are a factor in secondary burning mouth syndrome; specially in patients with hypothyroidism.