Prevalence and Distribution of Radix Paramolaris in the Mandibular First and Second Molars of an Iranian Population

OBJECTIVES: Inability to find supernumerary roots is one of the most important reasons for root canal therapy failures in molar teeth. This research aimed to determine the incidence and distribution of radix paramolaris in permanent mandibular molars of the population of Kerman. Iran over 2016–2017. MATERIALS AND METHODS: This study was performed on a collection of 500 extracted permanent mandibular first and second molars selected by random from different dental centers in Kerman without recording the sex and age of the patients as inclusion criteria. The incidence of additional mesiobuccal root (radix paramolaris), the average root length and morphology of this root was carefully determined following the Calberson and Alexanderson classification pattern. RESULTS: The incidence of radix paramolaris was 1.2% in mandibular first molars (0.8% Type A and 0.4% Type B) and 0.8% in mandibular second molars (0.4% Type A and 0.4% Type B) of this population. Fischer's Exact test showed that the difference in frequency of the radix paramolaris between first and second mandibular molars of this population was not statistically significant (two-sided P = 0.0001). The average length for radix paramolaris was 13.05 mms in mandibular first and second molars in this study. CONCLUSION: Radix paramolaris was found more frequently in mandibular first molars than in mandibular second molars in this sample of 500 mandibular molars. The rate of 1.2% in first molars seems to be higher than reported rates in European or Caucasian populations where the prevalence is typically <0.5%.