This systematic review and meta-analysis investigated the association between periodontitis (PD) and dental caries. The study included 18 studies and found that PD was associated with an increased risk of dental caries, with an odds ratio (OR) of 1.57 (95% CI: 1.20–2.07). The risk was higher in both crown and root caries, with ORs of 1.03 and 2.10, respectively. Additionally, patients with PD had a higher mean number of decayed, missing, and filled teeth (DMFT) and decayed and filled root teeth (DFR). Conversely, patients with caries had an elevated risk of PD, with an OR of 1.79 (95% CI: 1.36–2.35). However, Streptococcus mutans, a main caries pathogen, was negatively correlated with several main periodontitis pathogens. The study concluded that there is a positive clinical correlation between PD and caries, but the associated pathogens are antagonistic. Further research is needed to understand the mechanisms and develop prevention strategies for these two prevalent oral diseases.This systematic review and meta-analysis investigated the association between periodontitis (PD) and dental caries. The study included 18 studies and found that PD was associated with an increased risk of dental caries, with an odds ratio (OR) of 1.57 (95% CI: 1.20–2.07). The risk was higher in both crown and root caries, with ORs of 1.03 and 2.10, respectively. Additionally, patients with PD had a higher mean number of decayed, missing, and filled teeth (DMFT) and decayed and filled root teeth (DFR). Conversely, patients with caries had an elevated risk of PD, with an OR of 1.79 (95% CI: 1.36–2.35). However, Streptococcus mutans, a main caries pathogen, was negatively correlated with several main periodontitis pathogens. The study concluded that there is a positive clinical correlation between PD and caries, but the associated pathogens are antagonistic. Further research is needed to understand the mechanisms and develop prevention strategies for these two prevalent oral diseases.