替牙早期上颌阻生中切牙矫治过程中的支抗控制

目的评价替牙早期上颌阻生中切牙矫治过程中的支抗控制及矫治要点。方法选择常州市口腔医院正畸科替牙早期上颌中切牙阻生需进行牵引治疗的骨性Ⅰ类患者11例,治疗前拍摄CBCT以确定上颌阻生中切牙的位置、外形、牙根及周围组织等情况,根据情况进行治疗,牙齿位置基本正常即主动加力结束即视为矫治结束,分析矫治过程中的支抗控制及矫治效果。结果替牙早期上颌阻生中切牙矫治过程中,正常萌出的上切牙和第一磨牙或第二乳磨牙基本可以提供所需的支抗;阻生严重者,先采用活动矫治器牵引阻生牙后再采用固定矫治器进行精细调整。结论替牙早期阻生中切牙的保留对面部美观至关重要,采用必要的支抗控制进行保存治疗可以取得良好的效果;采用CBCT对阻生中切牙进行精确分析也是取得良好矫治效果的必要保障。     

上颌第一前磨牙影像学根管形态分析

目的采用锥形束CT(CBCT)探讨上颌第一前磨牙根管的解剖形态,了解其常规形态及变异形态。方法收集176例患者的双侧上颌第一前磨牙的CBCT影像学资料,CBCT资料使用NNT软件进行扫描观察,探究根管类型和根管分布情况。结果 352个上颌第一前磨牙根管分型:Ⅰ型30例(8.52%),Ⅱ型92例(26.1%),Ⅳ型225例(63.9%),Ⅵ型3例(0.85%),Ⅷ型2例(0.56%)。结论上颌第一前磨牙牙根形态多样,且根管形态的类型较为复杂。通过影像学诊断方法更加深入的了解其解剖形态,对临床治疗具有重要意义。     

无髓牙根纵裂的诊断

目的：探讨无髓牙（即经过根管治疗的牙）根纵裂的临床特点和诊断依据。方法14例患牙经影像学检查、翻瓣或拔除等方法确诊的根纵裂无髓牙,回顾性分析其病史、临床体征及影像学检查结果。结果14例确诊患牙中,磨牙6颗,前磨牙4颗,前牙4颗。14例患牙均有牙冠修复（其中10例有桩核）。14例牙周探诊均可及局限性的深牙周袋（≥7 mm）,根尖片表现以牙槽骨垂直吸收为主。5例患者有锥形束 CT 检查,其中1例通过 CT 直接诊断为根纵裂。结论无髓牙根纵裂的诊断可根据病史、临床特点、影像学检查等综合判断。     

3D整合牙颌模型在无托槽隐形治器设计中的应用

目的 探讨将3D整合牙颌模型应用于无托槽隐形矫治器设计,以便精确控制牙根在颌骨中的移动.方法 将基于锥形束计算机断层扫描( CBCT)的牙颌模型和基于机构光扫描的牙冠模型自动配准,建立能精确显示牙列、咬合、牙根及颌骨的3D整合牙颌模型.在3D整合牙颌模型上进行模拟排牙和虚拟矫治,然后应用激光快速成型技术制作无托槽隐形...     

牙科CT系统测量正常人牙齿外部形态数据的可行性研究

目的:探讨牙科CT系统测量正常人牙齿形态数据的可行性。方法:对10名正常青年人(男性6例、女性4例,年龄24～27岁)进行牙科CT扫描,用其随机自带软件测量牙冠宽度及厚度,并制取上述10名青年人上下颌全牙列石膏模型,用游标卡尺测量模型的牙冠宽度及厚度;应用SPSS软件对牙科CT系统与游标卡尺所测数据进行统计学分析。结果:牙科CT系统与游标卡尺对牙冠宽度及厚度进行的两次测量结果均无统计学差异(P>0.05);牙科CT与游标卡尺对牙冠宽度、厚度两次测量结果的平均值无统计学差异(P>0.05)。结论:牙科CT系统测量牙齿外部形态数据稳定、可靠,可用于测量活体全牙列牙齿外部形态数据。     

Observer ability to detect ex vivo simulated internal or external cervical root resorption

Introduction

The objective of this study was to assess observer ability to detect ex vivo simulated internal and external cervical root resorption.

Methods

A total of 90 single-rooted mandibular anterior teeth were split along the coronal plane. By using a 0.5-mm diameter round bur, 50 of the teeth were drilled to simulate resorptive cavities (25 internal and 25 external cervical resorption), and the remaining 40 teeth were left without surface defects. The sectioned teeth were rejoined and placed in the alveolar sockets of a dry human mandible in groups of 6 and imaged with intraoral film by using 3 different angulations and with a cone-beam computed tomography (CBCT) unit. Film and CBCT image sets were evaluated twice by 3 separate observers. Teeth were scored for the presence and location of resorption by using a 5-point scale. Intraobserver and interobserver kappa coefficients and Az values were calculated for each observer and image set. Differences between modalities were compared by using z statistics, with the significance level set at α = 0.05.

Results

Both intraobserver and interobserver agreements were statistically higher (p < .05) for the Iluma CBCT images than for the intraoral images. Az values for CBCT images were also statistically higher (p < .05) than for film images for all observers and readings. In addition, kappa and Az values of external cervical resorption cavities were statistically higher (p < .05) than those of internal cervical resorption cavities for all observers, image types, and readings.

Conclusions

High-resolution Iluma CBCT images performed better than film in the ex vivo detection and localization of simulated internal and external cervical root resorption.     

Vertical palatal bone dimensions on lateral cephalometry and cone-beam computed tomography: implications for palatal implant placement

Objectives: To evaluate the necessity of three‐dimensional imaging (computed tomography [CT]/cone‐beam computed tomography [CBCT]) for paramedian insertion of palatal implants. Material and methods: Lateral radiographs and CBCT scans were performed from 18 human skulls. For lateral cephalometry, the nasal floor (right/left) and the oral hard palate of all skulls were lined with a tin foil for contrast enhancement. The quantity of vertical bone as measured on lateral radiographs was compared with CBCT measurements obtained in median and parasagittal planes and at minimum bone height. Spearman's rank correlation coefficients were determined for bivariate correlation analysis. Results: The median palatal bone height on CBCT (mean 8.98 mm; standard deviation [SD] 3.4) was markedly higher than the vertical height seen on lateral radiographs (mean 6.6 mm; SD 3.2). Comparing lateral cephalometry with CBCT, the strongest association was observed at the minimum palatal bone height (r=0.926; P<0.001; Spearman's rank correlation coefficient). Conclusions: Lateral radiographs allow accurate and adequate assessment of vertical bone before paramedian insertion of palatal implants. The vertical bone dimension as displayed on lateral cephalometry reflects the minimum bone height rather than maximum bone in the median plane. Therefore, a preoperative CT or CBCT is only indicated when the lateral cephalometry reveals a marginal quantity of bone. To cite this article:
Jung BA, Wehrbein H, Heuser L, Kunkel M. Vertical palatal bone dimensions on lateral cephalometry and cone‐beam computed tomography: implications for palatal implant placement.
Clin. Oral Impl. Res. 22 , 2011; 664–668
doi: 10.1111/j.1600‐0501.2010.02021.x     

Multiple idiopathic cervical resorption: case report and discussion of management options

AIM: To present a case of cervical root resorption affecting all teeth and resulting in multiple tooth loss. SUMMARY: A healthy 33-year-old Chinese male, with no contributory medical or family/social history, presented with generalized cervical root resorption. Lesions varied in severity amongst teeth and even involved an impacted third molar. All cervical root surfaces were affected and lesions often extended coronally, undermining enamel. CBCT demonstrated that the lesions were more extensive and more widely distributed than was seen using conventional radiography. Bone extended into many resorptive defects but without clinical evidence of ankylosis. Periodontal probing, pulp testing, percussion sound and mobility were within normal limits. Key learning points ? Aetiology of the generalized idiopathic cervical root resorption is uncertain. ? Management is complex, and options have included surgical exposure and restoration of affected sites, extraction and submergence of affected roots. ? A staged approach involving early intervention with restoration of resorptive defects, followed by progressive extraction and replacement with implant-supported prostheses is recommended.     

Guided surgery for implant therapy

New three-dimensional diagnostic and treatment planning technologies in implant dentistry have expanded on concepts of a team approach to the planning and placement of dental implants. The accurate and predictable placement of implants according to a computer-generated virtual treatment plan is now a reality, taking the virtual plan from the computer to the patient clinically. Recent advances in three-dimensional imaging in dentistry, in combination with the introduction of third-party proprietary implant planning software and associated surgical instrumentation, have revolutionized dental implant diagnosis and treatment and created an interdisciplinary environment in which communication leads to better patient care and outcomes.