目的: 利用锥形束CT和螺旋CT分析上颌根尖周囊肿的三维影像学特点。方法: 收集2012年12月至2018年1月就诊于北京大学口腔医院并有完整临床资料、病理诊断及锥形束CT或螺旋CT影像的上颌根尖周囊肿患者67例,分析其影像学特点,包括病变大小、形态、膨隆情况、内部结构及与周围组织的关系等。根据病变累及牙的范围分为三型:(1)单牙型:病变仅累及1枚病原牙的根周骨质;(2)邻牙受累型:病变除累及1枚病原牙的根周骨质外,向近中和/或远中累及1枚邻牙牙根;(3)多牙型:病变累及≥4枚相邻牙位的根周骨质。另外,根据矢状位图像囊肿与牙根长轴的关系分为向心(病原牙牙根长轴指向病变中心)、偏腭(囊肿主体位于病原牙根的腭侧)及偏唇颊(囊肿主体位于病原牙根的唇颊侧)三种。结果: 共纳入67例患者,男性38例,女性29例,年龄13~77岁,其中46例(68.7%)位于上颌前部,65例(97.0%)为类圆形或椭圆形,43例(64.2%)唇颊侧骨板膨隆,37例(55.2%)腭侧骨板膨隆,27例(40.3%)累及鼻底,26例(38.8%)突入上颌窦,9例(13.4%)可见牙根吸收。近远中最大径为(20.89±8.11) mm,唇(颊)腭向最大径为(16.70±5.88) mm。4例患者的病原牙已拔除,其余63例患者根据病变范围分为单牙型14例、邻牙受累型26例、多牙型23例,根据病变与牙长轴关系分为向心46例、偏腭15例、偏唇颊2例。结论: 根尖周囊肿以上颌前部多见,多表现为类圆形或椭圆形,少数病变尺寸较大。根据病变与病原牙的近远中向累及范围分为单牙型、邻牙受累型和多牙型。矢状面上,病变与病原牙长轴多为向心关系,少数偏腭或偏唇颊。

Objective: To analyze the three-dimensional radiographic characteristics of maxillary radi-cular cysts using cone-beam computed tomography (CBCT) and spiral CT. Methods: Clinical records, histopathological reports, and CBCT or non-enhanced spiral CT images of 67 consecutive patients with maxillary radicular cysts were retrospectively acquired, and radiographic features, including size, shape, expansion, internal structure and relationship with the surrounding tissues, were analyzed. The lesions were divided into three types according to the involved tooth number, as follows: type Ⅰ (single tooth), the epicenter of the cyst was located at the apex of a nonvital tooth, without involvement of the neighbo-ring tooth; type Ⅱ (adjacent tooth involvement), the cyst was located at the apex of a nonvital tooth with involvement of the mesial and/or distal tooth root; and type Ⅲ (multi-teeth), the cyst involved the apexes of ≥4 teeth. Besides, these cysts were classified as another three types on sagittal views, as follows: centripetal, the root apex was oriented centripetally to the center of the cyst; palatal, the cyst was located mainly at the palatal side of the apex; and labial/buccal, the cyst was located mainly at the labial/buccal side of the apex. Results: Totally, 67 patients with maxillary radicular cysts were acquired, including 38 males and 29 females, and their ages ranged from 13 to 77 years. Among them, 46 lesions (68.7%) were located in the anterior maxilla and 65 (97.0%) were round or oval. Labial/buccal cortex expansion was present in 43 cases (64.2%) and palatal cortex expansion in 37 cases (55.2%). The nasal floor was invaded in 27 cases (40.3%), the maxillary sinus was invaginated in 26 cases (38.8%), and root resorption was present in 9 cases (13.4%). The average diameter of lesions was (20.89±8.11) mm mesio-distally and (16.70±5.88) mm bucco-palatally. In spite of the 4 residual cysts, the remaining 63 lesions included 14 type Ⅰ, 26 type Ⅱ and 23 type Ⅲ cysts according to the involved tooth number. Besides, the 63 lesions included 46 centripetal, 15 palatal and 2 buccal cysts on sagittal views. Conclusion: The maxillary radicular cysts were frequently well-circumscribed round or oval radiolucency, with significantly different sizes. According to the involved tooth number, it can be divided into single tooth, adjacent tooth involvement and multi-teeth types. On sagittal views, the root-cyst relationship was centripetal in most cases, while a minority of cysts expanded palatally or buccally.