Dental caries is found to be the most common oral health issue and is a widespread oral disease in children around the globe.Interproximal caries lesions develop between the contacting proximal surfaces of two adjacent teeth.In primary dentition, Molars are the teeth most often affected. The aim is to investigate the Prevalence of distal caries in mandibular first primary molar and mesial caries in second molar .A University based study was conducted on mandibular first and second molar. Data collection was done by reviewing the patient records and analysing the data of 572 and 663 patients with class II caries in mandibular right and left molars respectively and 182 patients with distal caries in mandibular first primary molar and mesial caries in second molar from June 2020 to March 2021, then excel tabulation, Statistical analysis was done using SPSS and Pearson chi-square test was performed.The age ranged 2 to 12 years. Out of the total population 41.57% were female and 58.43% were males.The results showed that 50.55% represents prevalence of distal caries in mandibular left first molar and mesial caries in mandibular left second molar, while 49.45% represents prevalence of distal caries in mandibular right first molar and mesial caries in mandibular right second molar.The conclusions of the study is that in 14.74% of cases, the distal caries in the mandibular first primary molar is associated with mesial caries in the second molar

Mesial caries,Distal caries, mandibular first, second molar,Novel approach