CRP and periodontitis: Recent studies have reported that some hematological parameters that are pro-inflammatory mediators such as the neutrophil–lymphocyte ratio (NLR) [6], thrombocyte-lymphocyte ratio (PLR) [7], C-reactive protein (CRP) level [8, 9], neutrophil [10], and thrombocyte counts [11] are increased in patients with periodontitis and these parameters are associated with the severity of periodontitis [12].