Wu Zhi-Fang, Lu Ling-Jiao, Zheng Hai-Yan, Tu Yan, Shi Ying, Zhou Zi-Huai, Fang Lin-Xian, Fu Bai-Ping
Department of Pediatric Dentistry, The Affiliated Hospital of Stomatology, School of Stomatology, Zhejiang University School of Medicine, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Hangzhou 310006, Zhejiang Province, China.
Department of Prosthodontics, The Affiliated Hospital of Stomatology, School of Stomatology, Zhejiang University School of Medicine, Key Laboratory of Oral Biomedical Research of Zhejiang Province, Hangzhou 310006, Zhejiang Province, China.
World J Clin Cases. 2021 Apr 26;9(12):2944-2950. doi: 10.12998/wjcc.v9.i12.2944.
Several previous studies have reported an unusual root formation in which a fractured apical fragment of an immature root continued to develop independent of the main root after trauma to an immature tooth. To date, there have been only rare reports of the continuing apical formation of the fractured root associated with dens evaginatus (DE). This paper presents a case of a separated root tip formation associated with a fractured tubercle of DE.
An 11-year-old boy was referred for gingival sinus on the buccal side of the right mandibular second premolar (tooth # 45). Clinically, tooth # 45 was free of caries, but there was a sign of a fractured tubercle of DE on the occlusal surface. Radiography showed that the root canal of tooth # 45 was widely radiolucent. A separated root apex was found apically under the main root and was nearly completely formed with an apical orifice at the apical tip. Tooth # 45 was diagnosed as tubular fracture of DE with chronic apical periodontitis. A revascularization technique was recommended to treat the tooth. At 3-mo and 1-yr follow-up, the patient remained asymptomatic. Periapical radiography revealed that the separated root tip distally drifted with closure of the apex. However, the root length and thickness of the main root did not increased.
Clinicians should be aware that even if tubercle of DE is fractured in an immature tooth, the root tip may be separated from the main root and completely formed.
此前有多项研究报道了一种不寻常的牙根形成情况，即未成熟牙齿受外伤后，未成熟牙根的根尖折断片段可独立于主根继续发育。迄今为止，仅有罕见报道称与畸形中央尖（DE）相关的折断牙根根尖持续形成。本文报告一例与DE折断结节相关的根尖分离形成病例。
一名11岁男孩因右下颌第二前磨牙（45号牙）颊侧牙龈窦道前来就诊。临床检查发现，45号牙无龋齿，但咬合面上有DE折断结节的迹象。影像学检查显示，45号牙根管广泛透射影。在主根根尖下方发现一个分离的根尖，其根尖孔几乎完全形成，位于根尖顶端。45号牙被诊断为DE管状骨折伴慢性根尖周炎。建议采用牙髓血运重建技术治疗该牙。在3个月和1年的随访中，患者无症状。根尖片显示，分离的根尖向远中移位，根尖孔闭合。然而，主根的长度和厚度并未增加。
临床医生应意识到，即使未成熟牙齿的DE结节发生骨折，根尖仍可能与主根分离并完全形成。
