Introduction : Periodontitis and dental caries may be synergistically associated, negatively associated, or completely independent.The aim of this study was to evaluate the correlation between these two diseases and investigate the prevalence of dental caries in periodontitis.

Methods: This cross- sectional study has been performed in 180 samples in two groups: periodontal and control group during 2012-2013 in Babol Dental School.All 180 patients were divided into two groups, including 90 cases with chronic periodontitis as the periodontal group (PG) and 90 cases with healthy gums as the control group ( probing depth between 2- 3 mm) (HG).Clinical measurments including Gingival Index ( GI), Bleeding Index( BI), Clinical Attachment Loss (CAL), Periodontal Pocket Depth (PPD) were used to assess the severity of periodontal disease . The clinical features of control group were healthy gums , probing less than 3 mm in depth, and CAL< 1mm . The examination to measure AL was conducted using a Williams’s periodontal probe .In chronic periodontitis group , the patients had GI≥1 and CAL ≥ 1 .The assessment of caries of patients was conducted using bitewing radiography for proximal caries detection , dent on the use of explorer and direct observation. A p-value≤0.05 is considered as significant.

Results: The results of this study showed that the mean number of decayed and filled teeth (DFT) in periodontal group was 4.32 ± 0.17, and in healthy group was 2.16 ± 0.17.DFT in males with periodontitis was 4.85 ± 0.17 and in females was 4.3 ± 0.17 ,while the healthy males was 2.54 ± 0.17, and females was 2.25 ± 0.17 therefore, the mean DFT in the periodontal group was more than the healthy group (p≤0.05) .

Conclusion : Based on our findings, in patients with periodontitis, more dental carries were more significant than the healthy group.