Spontaneous regression of dentigerous cyst in a impacted mandibular first permanent molar with eruptive potential: a case report

Surgery is the main treatment for dentigerous cysts. Although the treatment concept has shifted from radical lesion removal to function‑preserving strategies, surgical trauma and related risks are still hard to avoid completely. The strategy of spontaneous fenestration may be preferred in a few dentigerous cysts in children. A 6-year-old boy was referred because of the delayed eruption of a left mandibular posterior tooth. Panoramic radiographic examination revealed a well-defined radiolucent area measuring approximately 22 × 18 mm around the crown of the left mandibular first permanent molar (tooth 36), which was vertically impacted at Nolla stage 7 and extended to the distal root of the left mandibular second primary molar. A dentigerous cyst of tooth 36 was diagnosed. Because the tooth 36 presented eruptive potential and no obvious coronal bony barrier, only regular follow-up was adopted. At 6‑month follow‑up the cyst decreased to about 16 × 11 × 14 mm on CBCT。After two years, tooth 36 had erupted spontaneously and the cyst had completely resolved. The tooth 36 had an immature root with no bony obstruction coronally and a small-to-medium cyst volume and lack of adverse effects, and thus conservative monitoring was adopted. During follow-up, the cyst progressively decreased in size and the affected tooth showed a clear tendency for occlusal eruption, ultimately resulting in complete resolution of the cyst and spontaneous eruption of the tooth, confirming that this strategy may be a feasible option. We also reviewed relevant literature and analyzed the underlying mechanisms, providing evidence for more conservative clinical management strategy of dentigerous cysts in children.