Periodontitis As A Risk Factor For Stroke: A Systematic Review And Meta-Analysis.

This systematic review and meta-analysis investigate the association between periodontitis and stroke. This review followed the methods established by the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Searches were conducted in five databases and two sources of grey literature. After the selection of the articles, a risk of bias evaluation was performed. Three meta-analyzes were performed: Assessing the overall association between stroke and periodontitis in case-control studies; Ischemic stroke and periodontitis in case-control studies; The association between stroke and periodontitis in cohort studies. Heterogeneity was assessed using the I2 index and the odds ratio was also calculated (p < 0.05). The Grading of Recommendations Assessment, Development and Evaluation (GRADE) was applied to evaluate the level of evidence. 2193 potentially relevant studies were identified, with 10 studies included in qualitative and quantitative analysis. All the articles were considered with low risk of bias and a low level of certainty. The results demonstrated a positive association between both disorders and increased risk for stroke among cohort studies (RR 1.88 [1.55, 2.29], p<0.00001, I2=0%) and for ischemic stroke events in case-control studies (RR 2.72 [2.00, 3.71], p<0.00001, I2= 4%). Periodontitis may represent a risk factor for stroke, especially in ischemic events. However, new studies with a robust design are necessary for a reliable conclusion.

Dental enamel bleached for a prolonged and excessive time: Morphological changes.

This work aimed to evaluate the roughness, microhardness, ultrastructure, chemical composition and crystalline structure in submitted teeth to a prolonged home bleaching regimen with 10% carbamide peroxide (10% PC) for different periods. The specimens were divided into the following groups: G1: negative control (application of water-soluble gel); G2: tooth whitening group (positive control), under application time recommended by the manufacturer (4h/14 days); G3: prolonged whitening 50%, under prolonged time recommended by the manufacturer in 50% (4h/21 days); G4: excessive whitening 100%, under exceeded manufacturer recommended time by 100% (4h/ 28 days). The results were evaluated descriptively and analytically. There were no changes in the roughness in any of the evaluated groups. However, the microhardness decreased in the G4 group. Scanning electron microscopy showed changes in the enamel surface of groups G2, G3 and G4. Dispersive X-ray spectroscopy identified changes in the concentration of chemical elements O, Mg, P, K in all groups. Thus, this study showed that prolonged home bleaching could cause changes in the ultrastructure, chemical composition and microhardness of the enamel.