Table 1.

Study findings for rheumatoid arthritis associated with periodontitis

Reference	Study type(s)	Outcome	Strength of evidence
Kaur et al. 201314	SR: 16 case–control studies 3 experimental studies	Association between RA & tooth loss, CAL & ESR CRP, IL-1 β & other markers Some evidence of positive outcome of SRP on RA	Good Moderate Weak
Kaur et al. 201415	SR & MA: 4 RCTs/1 CT	Effects of NSPT on various biochemical markers Statistically significant reductions only for ESR (but not CRP)	Weak
Cerqueira Calderaro et al. 201716	SR & MA: Same 4 RCTs as Kaur et al.15	No significant reductions in ESR but statistically significant reductions in DAS28 Results conflicted with Kaur et al.15	Strong for DAS28
Tang et al. 201717	SR & MA: 8 case–control studies	Statistically significant association Higher prevalence of periodontitis in those with RA. OR: 4.68 (95% CI, 3.11–7.05) Higher levels of P. gingivalis IG-G in RA patients	Strong (but studies lower level)
de Oliveira Ferreira et al. 201918	SR & MA: 2 cohort studies 7 cross-sectional studies	Included those with and without periodontitis; used RA as an outcome 7 of the 9 studies reported associations but only 3 studies were used in MA; results were inconclusive	Inconclusive Higher level studies required
Hussein et al. 202019	SR & MA: 8 case–control studies but 2 eliminated due to high risk of bias	Explored if a bidirectional relationship exists No significant effects of RA on periodontitis Reported significantly worse RA disease activity in those with periodontitis (p < 0.001)	None