3-rooted Primary Mandibular Second Molars among Chinese patients

Resident: Swan

Article Title: Prevalence of 3-Rooted Primary Mandibular Second Molars among Chinese Patients
Author: Liu et al.

Journal: Pediatric Dentistry
Volume (Number): 32 (2)
Major Topic: Primary molar anatomy
Type of Article: Retrospective Study
Main Purpose: Determine the prevalence of 3-rooted primary mandibular second molars in vertical bitewing radiographs obtained from a group of Chinese patients
Overview of method of research: Vertical bitewing radiographs of 185 patients showing bilateral primary mandibular second molars were evaluated by two calibrated dentists, a pediatric dentist, and an endodontist. The presence of an extra root was determined by the crossing of radiolucent lines corresponding to the PDL space of the extra root superimposed on the molar’s pulp floor. Disagreements between examiners were resolved by consensus between 2 investigators.

Findings: An extra distal root in mandibular primary second molars was found in 18/185 (10%) of the patients examined, more specifically, in 23 of the 370 total teeth. Bilateral 3-rooted molars were found in 5 patients (2.7%). The occurrence of such molars did not differ significantly between males and females.

Key Points/Summary: Various studies have examined the prevalence of 3-rooted primary mandibular second molars among different populations. The prevalence found in this study (10%) is on the high end compared to other studies that have been done with larger populations. Other studies suggest that if the primary second molar has three roots, there is a high probability that the permanent first molar will also have one. This is based on theory more than science and more studies need to be done to substantiate it.

Assessment of Article: Decent study about a very specific population. Very subjective determination of root anomalies from radiographs. Hard to generalize these results. Here’s to the 2nd years not missing any board questions about Chinese mandibular second molars!