This study aims to investigate the relationship between dental caries and periodontal health by examining the clinical parameters and levels of some biochemical markers in the gingival crevicular fluid (GCF) of the teeth. In 22 children, 22 maxillary primary canine teeth and a pair of primary molars in a total of 38 quadrants were examined. The control group (C) consisted of children who had at least 1 caries-free primary maxillary canine. The test group (T) consisted of children who had a pair of primary molars where the interproximal contact was lost due to the caries in the same quadrant. Their primary molars were restored with compomer. The teeth were evaluated based on clinical values (plaque index, gingival index, and probing depth) and biochemical values in GCF before (C-0, T-0) and after a 6-month treatment (C-1, T-1). While total amounts of interleukin-1 beta and vascular endothelial growth factor in GCF in T-0 were significantly higher than in C-0 (P<0.001), osteocalcin was statistically insignificant (P>0.05). Clinic parameters in T-0 were significantly higher than in C-0 and T-1. Also these parameters in C-0 were higher than in C-1 (P<0.01). Clinical and biochemical parameters in GCF in the teeth with interproximal caries might show symptoms of periodontitis.