“Ringlike hard mass” surrounding the root of a primary tooth in a young child: report of an unusual case

Abstract

<h3>Background</h3> Several lesions of diverse origin may be detected in the oral cavity of young children, affecting the oral mucosa, jaws, or teeth. Their clinicopathologic features may show considerable overlap. We present an interesting case of a "ringlike hard mass" of initially unknown nature around the cervical area of a primary tooth in a young child, and we discuss the diagnostic challenges. <h3>Case Summary</h3> A 2-year-old girl presented for evaluation of a painless lesion surrounding a primary tooth, first noticed before she was 5 months of age. Her medical history was unremarkable without any history of trauma. The clinical examination revealed a yellowish cylindrical mass, hard in consistency, completely surrounding the cervical area of the left first primary lower incisor. It was nonremovable, strongly adhered to the root surface. With a provisional clinical diagnosis of a tooth abnormality (eg, hypercementosis), a periapical radiograph revealed acylindrical radiopacity of mild intensity enveloping the tooth cervix, extending approximately 2 mm apically. Based on an expert oral and maxillofacial radiologist's consultation, a diagnosis of a foreign body around the tooth was favored, although no relevant anamnesis was given. A watch-and-wait policy was adopted, and the patient was observed regularly in follow-up for the next 4 years with mild but progressive gingival recession, revealing a larger part of the ringlike structure. Radiographically, the "lesion" did not show any changes; however, a progressive but overall limited resorption of the alveolar bone in the cervical area was observed. At age 6 years, the tooth was extracted, and, on gross examination, a cylindrical structure was detached with difficulty from the tooth, confirming its nature as a foreign body, most likely an accidentally misplaced rubber ringlike toy part. Subsequent follow-up confirmed uneventful eruption of the permanent central incisor. <h3>Conclusions</h3> Accidental impregnation of a foreign body in the oral soft tissues is an unusual but not rare event in children. However, the occurrence of a foreign body completely surrounding the cervix of a tooth, eventually becoming inseparable possibly due to calcification, is probably very rare. Although harmless, the peculiar clinical and radiographic appearance may cause diagnostic dilemmas.