The serum level of creatinine (<i>P</i>=0.02), cystatin C (<i>P</i>=0.013), calcium (<i>P</i>=0.046) and phosphorus (<i>P</i>=0.037) had a significant correlation with severity of periodontitis and increase in CAL.<h4>Conclusion</h4>Increase in the serum levels of albumin and ferritin was related to the progression of gingivitis to periodontitis. This evidence concerns the gene CST3 and gingivitis.