Background: Periodontitis is a chronic inflammatory disease with local and systemic implications. Evidence suggests consistent hematologic changes associated with periodontitis. Our aim was to critically appraise the available evidence on hemogram, leukogram and thrombogram alterations in otherwise healthy patients suffering from periodontitis when compared to controls. Methods: For this systematic review (SR), we searched MEDLINE, Web of Science, EMBASE and The Cochrane Library (CENTRAL) for studies published up to June 2020. Both observational and interventional studies with baseline standard hematologic levels were included. Outcomes of interest were baseline hemogram, leukogram and thrombogram values and the impact of periodontitis treatment on these outcomes. Upon risk of bias assessment, data extraction both qualitative and quantitative (standardised mean differences MD) analyses were performed. Random-effects meta-analyses were performed to provide pooled estimates. PRISMA guidelines were followed (PROSPERO reg: CRD42020164531).Findings: A total of 45 studies, 8 intervention and 37 case-control, were identified after the final search of 3012 titles. Following quality assessment, 43 articles were deemed as of low risk of bias whilst two manuscripts with moderate risk. Meta-analyses confirmed that periodontitis was associated with both white and red cells lineages. Severe chronic periodontitis was associated with greater White Blood Cells count (WBC) (SMD of 0.53, 95% CI 0.26-0.79) when compared to controls. Patients with periodontitis were associated with higher number of neutrophils (MD of 7.16%, 95% CI: 5.96-8.37) and lower Mean Platelet Volume (MD of 0.30 fL, 95% CI: 0.49 --0.10) than healthy participants. Nonsurgical periodontal treatment (NSPT) was associated with a decrease in WBC levels (WMD of 0.28 10 9 /L, 95% CI -0.47 --0.08) in patients suffering from chronic periodontitis.Interpretation: Periodontitis is associated with hematologic changes (SORT A recommendation). Higher WBC, neutrophils, erythrocyte sedimentation rate and lower MPV levels are the most common blood counts findings. The association between periodontitis and WBC could be causal in nature. Further research in assessing whether periodontitis causes circulating blood cells changes and identify the molecular mechanisms behind these associations are warranted.

Background: Several lines of evidence suggest a bi-directional association between Rheumatoid Arthritis (RA) and Periodontitis (PD). Our aim was to systematically appraise the evidence on the association between RA and PD in terms of clinical and laboratory outcomes. Methods: An electronic search of several databases (PubMed, EMBASE, MEDLINE, LILACS, CINHL, Scopus, Web of Science, The Cochrane Library, OpenGrey and Google Scholar) was conducted up to March 2019 (PROSPERO CRD42018107817) by two independent reviewers. Observational studies included in the review were quality-appraised using the Newcastle-Ottawa Scale (NOS) tool. Random effects models were used for quantitative analyses. Results: A total of 8 case-control studies were identified after the final search of 1491 titles. Following quality assessment, 2 studies were excluded due to the high risk of bias, while the remaining 6 were further analysed. Meta-analyses revealed no substantial effect of RA on the Probing Pocket Depth (PPD) and Clinical Attachment Level (CAL) of patients with PD when compared to controls but high degree of study heterogeneity was found. To the contrary, PD was associated with substantially worse RA disease activity as assessed by an increase in the DAS28 score of 0.74 (0.25-1.24, 95%CI, p<0.001). Conclusion: There is consistent evidence suggesting that PD is associated with worse RA clinical activity as assessed by DAS28 scores whereas, RA patients do not have worsen PD clinical outcomes.

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease mediated by immune complexes presenting with various systemic manifestations. Its prevalence has been estimated at 20 to 70 per 100 000 cases each year. Incidence rates for SLE demonstrates 1 to 10 per 100 000 each year and affecting mostly women in the second and third decade of their life 1 .