First Permanent Molar Caries and its Association with Carious Lesions in Other Permanent Teeth

Introduction: Dental caries is most prevalent in first permanent molars and it is bilaterally distributed in permanent maxillary and mandibular molars. It is assumed that dental caries in first permanent molar is related to caries in other permanent teeth possibly due to its infectious and transmissible nature. However, there is limited data about a relationship between caries in first permanent molar and other permanent teeth. Aim: To assess the association between dental caries in first permanent molar and other permanent teeth in school children. Materials and Methods: This cross-sectional study was conducted on male intermediate school children (12-15 years) in Dammam, Saudi Arabia in 2016. A sample of 1250 children was randomly selected. Data collection involved clinical examination of caries using the World Health Organisation (WHO) criteria and a pilot-tested questionnaire. Training and calibration of examiners were conducted (k ≥0.6). Statistical analyses involved descriptive statistics, univariate and multivariate logistic and linear regressions using SPSS software. Results: Of 1250 children invited, 1109 participated with a response rate of 88.7%. The first permanent molars had the highest percentage of dental caries among all permanent teeth (50.4%) with a mean of 1.08 carious molars. This was followed by second permanent molars (prevalence=14.7%, mean number of decayed molars=0.25). The canines had the lowest prevalence of dental caries (1.8%) and the mean number of carious canines was 0.02. Logistic regression showed that caries in first permanent molars were significantly associated with higher odds of caries in incisors (OR=4.87), second molars (OR=4.26) and premolars (OR=3.57). It was found that a unit increase in the number of carious first molars was associated with a significant increase in the number of carious incisors, premolars and second molars. Conclusion: The study found associations between caries in first permanent molar with caries in other permanent teeth. School-based oral health promotion programs should start early to target young school children when first permanent molars start to erupt.