Background: The aim of the study was to determine whether the presence of two palatal roots (2PR) in permanent maxillary molars (PMMs) could be predicted by observing dental morphological traits during the clinical examination.
Materials and methods: A total of 18 second and 26 third PMMs with 2PR were examined from the collection of extracted teeth. The reference sample of 44 extracted PMMs with one palatal root was selected such that pairs of morphologically matching PMMs with one and 2PR were formed. The external morphology of these tooth pairs was examined under a stereomicroscope and distinguishing traits were registered. The Fisher's exact test was applied to examine differences between second and third PMMs. Additionally, the external morphology of 17 PMM with 2PR in 15 patients was analysed retrospectively.
Results: Extracted PMMs with 2PR possessed the following distinguishing morphological traits: crown wider on the palatal half (55.3%), double Carabelli cusps (23.7%), pronounced palatal indentation of the crown (20.5%), thick palatal enamel extension (16.3%), palato-radicular groove (11.6%) and palatal enamel pearl (2.3%). Differences between second and third PMMs were not statistically significant (p > 0.05). At least one distinguishing trait was present in 63.4% and 94.1% of extracted and clinically evaluated PMMs with 2PR, respectively. Omega-shaped deformation of the dental arch may be the first clinically observable clue to this root constellation.
Conclusions: Clinical examination of tooth morphology and shape of the dental arch is essential for the detection PMMs with 2PR.
Keywords: dental morphology; radix distolingualis; radix mesiolingualis; supernumerary root.