The role of clinical examination in the detection of permanent maxillary molars with two palatal roots

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

Morphometric analysis of three-rooted mandibular first molars in a Slovene population: A macroscopic and cone-beam computed tomography analysis

Background: This study examined the root morphology of mandibular first molars (MFMs) with radix entomolaris (RE), which presents diagnostic and therapeutic challenges for clinicians. Material and methods: A total of 17 three-rooted MFMs were taken from a collection of extracted teeth. Root lengths and levels of furcations were measured with a digital calliper. The pulp floor configuration, root canal systems, and RE canal curvatures were evaluated using the cone-beam computed tomography scans. Results: RE was either located disto-lingually, with its coronal portion fixed to the distal root (n =16) or mid-lingually (n = 1). A literature search identified four additional cases of MFMs with RE located mid-lingually. In the present study, RE was significantly (p ≤ 0.001) shorter than the distal root (DR) and the mesial root, on average by 2.04 mm and 3.15 mm, respectively. The level of the distal furcation was significantly (p = 0.003) lower than that of the mesiodistal furcation, on average by 1.39 mm. The average divergence angle formed by the cervical portions of the RE and DR canals was 53.14⁰. All RE canals were severely curved (> 25⁰) in buccolingual direction. The RE orifice was located slightly disto-lingually to considerably mesio-lingually from the DR orifice. Conclusions: The traditional assumption of a disto-lingually located RE needs to be changed, even though this is the most prevalently found variant of this anatomy. The additional variant includes the presence of a mid-lingually located RE, which has implications for the endodontic access cavity design