Morphological changes in the crown of mandibular molars with an additional distolingual root

Ki Rim Kim, Je Seon Song, Seong Oh Kim, Seung Hye Kim, Wonse Park, Heung Kyu Son

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Objective: The mandibular molars typically have two roots placed mesiodistally, but they occasionally have an additional distolingual (DL) root. This study was to determine the morphological characteristics of the crown of such mandibular molars. Design: Radiographic records and study models were collected from a Korean population (n = 86 patients). Each molar was assigned to either the experimental group (i.e. with a DL root) or the control group (i.e. without a DL root; n = 41 patients) based on the radiographic findings. The intercuspal distances of the first permanent molars (total, n = 100; control/experimental, n = 50/50) and primary second molars (46, 23/23), and the largest buccolingual/mesiodistal widths of those molars and primary first molars (42, 21/21) were measured for molars with and without a DL root. In addition, the correlation between the existence of a sixth cusp and a DL root was examined. Results: The crowns of first permanent and primary second molars with DL roots had significantly larger intercuspal distances between the distobuccal-distolingual cusp tips and a larger distal-area buccolingual width than those without the DL root (t-test; p < 0.05). There was no significant correlation between the existence of a sixth cusp and the presence of a DL root. Conclusions: The existence of a DL root was associated with larger buccolingual dimensions, especially in the distal area.

Original languageEnglish
Pages (from-to)248-253
Number of pages6
JournalArchives of Oral Biology
Issue number3
Publication statusPublished - 2013 Mar 1


All Science Journal Classification (ASJC) codes

  • Otorhinolaryngology
  • Dentistry(all)
  • Cell Biology

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