2026 年 4 巻 1 号 p. 11-15
Purpose : Enamel pearls (EPs) are ectopic enamel deposits on the root surface or within dentin that can affect periodontal therapy and imaging. Their occurrence in Japanese premolars remains underexplored. This study quantified EP prevalence and topographic localization with micro-computed tomography (μCT) and compared patterns between maxillary and mandibular arches.
Materials and Methods : We scanned 347 extracted premolars from Tokyo Dental College (maxilla n＝166, mandible n＝181) using μCT and identified rounded hyperattenuating foci as EPs. For each EP we recorded tooth-level prevalence, surface orientation, position on the root, and distance from the cementoenamel junction.
Results : EPs were found in 29/166 maxillary premolars (total 39 occurrences ; 1.34 per positive tooth) and 9/181 mandibular premolars (9 occurrences ; 1.00 per positive tooth). Prevalence was 17.50％ in the maxilla and 5.23％ in the mandible, significantly higher in the maxilla (p＜0.001). In the maxilla, 32 EPs were on the root surface and 7 were intradentinal EPs ; in the mandible, all EPs were root-surface only. By surface, maxillary EPs occurred on three faces except lingual, whereas mandibular EPs appeared on all root surfaces. Vertically, maxillary EPs were distributed throughout the root, while mandibular EPs clustered near the CEJ.
Conclusion : In Japanese premolars, EPs were detected more frequently than previously reported, with greater prevalence and a tendency toward multiplicity in maxillary premolars. The restriction of intradentinal EPs to the maxilla and arch-specific topography together suggest that these disparities reflect the more complex root morphology of maxillary premolars.
