Prevalence, symmetry and characterization of radicular concavities in human upper premolars

Radicular concavities, particularly in the maxillary premolar region, represent anatomical features that may significantly affect periodontal health. Therefore, the aim of this study was to evaluate the prevalence, dimensions and distribution patterns of radicular grooves in the maxillary premolar region using CBCT.

In total, 3492 CBCT image datasets from patients treated in all dentistry departments of the University Hospital of Mainz were screened. After applying strict inclusion criteria, a cohort of 836 patients with 1678 maxillary premolars could be included in this study. Horizontal depth, vertical extent, angulation, dentine wall thickness, and the distance from the cemento-enamel junction to the groove origin were analyzed.

Patients with concavities in at least one premolar were identified in 637 of 836 cases (76.2 %). The analyzed first premolars exhibited one or more concavities in 83.7 % (right) and 80.7 % (left) of teeth; second premolars were affected in 37.4 % (right) and 30.0 % (left). Mesial concavities were the most prevalent (≈ 60 %), followed by distal (≈ 35 %) and buccal (≈ 4 %). Mean mesial depth reached 1.09 ± 0.39 mm and vertical extension frequently exceeded 6 mm. Three concavities in one premolar increased the risk ratio for the contralateral homologue up to 33.33 (p < 0.001).

The present study provides a detailed morphological characterization of radicular concavities in maxillary premolars using three‑dimensional imaging. These anatomical structures should be considered in clinical decision‑making, especially in patients with a predisposition to periodontal disease.