CBCT和数字曲面体层片在颌骨后牙区牙种植术中应用研究

目的探讨CBCT与数字曲面体层片在牙种植术中的应用价值。方法 50例(58颗)牙种植治疗患者同时采用CBCT和数字曲面体层检查方法,将得到的术前颌骨牙槽骨量和术后骨结合的影像结果对照,分析差异性。结果下颌后牙区牙槽骨量不足CBCT检出阳性率为28.57%;数字曲面体层影像检查检出阳性率为7.14%。经过χ2检验,P<0.05,差异有统计学意义。上颌后牙区牙槽骨量不足CBCT和数字曲面体层影像检查检出阳性率分别为36.36%、9.09%。经过χ2检验,P<0.05,差异有统计学意义。种植牙术后3个月种植体未发生骨结合的阳性率,CBCT检出阳性率为3.45%(2/58);数字曲面体层片检出阳性率为8.62%(5/58),两者无统计学差异(P>0.05),实际临床检测发现仅1例未发生骨结合,阳性率为1.72%(1/58)。结论 CBCT是种植牙术前目前颌骨骨量测量较为可靠方法。CBCT与数字曲面体层片相比,数字曲面体层片存在变形,牙槽骨高度数据测量值普遍偏大。在术后检查中CBCT能更清晰地反映种植体周围骨质,评估种植手术的成功与否及对上部结构的修复有重要的指导意义。     

锥形束CT诊断颌面部异物1例

<正>张口受限为颌面外科的常见疾患,但颌面部异物引起张口受限多为个案报道[1-3]。准确定位异物位置及其形状大小,是外科手术取出异物,保证手术成功的关键。锥形束CT(cone beam computed tomography,CBCT)因其独特的三维成像特点,可以精确定位,更好地引导外科手术的顺利进行[4-6]。现对我院收治的1例颌面部异物引起的张口受限患者的临床资料进行报道,并结合文献回顾对CBCT在颌面异物诊断中的应用价值进行讨论。     

The Effect of Removable Partial Dentures on Alveolar Bone Resorption: A Retrospective Study with Cone‐Beam Computed Tomography

Purpose: The aim of this study was to compare vertical and horizontal mandibular alveolar bone resorption by measuring bone morphological variation in Kennedy Class II removable partial denture (RPD) wearers and non‐wearers using cone‐beam computed tomography (CBCT). Materials and Methods: In total, 124 sites in the CBCT scans of 62 (29 RPD non‐wearers, 33 RPD wearers) Kennedy Class II patients were analyzed retrospectively. Three‐dimensional representations of the mandible with superimposed cross‐sectional slices were developed with the CBCT scans to evaluate the mandibular alveolar height and width by measuring distances between the mandibular canal, mylohyoid ridge, alveolar crest, and lower border of the mandible in four regions (eight sites) of Kennedy Class II non‐wearers and wearers of RPDs. Results: Mandibular alveolar bone height and width were significantly lower in edentulous sites when compared with dentate sites in both Kennedy Class II non‐wearers and wearers of RPDs (p < 0.05). Additionally, mean vertical and horizontal mandibular bone resorption was significantly higher in RPD wearers than in non‐wearers (p < 0.05). Conclusions: Vertical and horizontal alveolar bone resorption was found to be higher in the RPD wearing patients when comparing the dentate and edentulous sites.     

Biomedical Ti–Mo Alloys with Surface Machined and Modified by Laser Beam: Biomechanical,Histological, and Histometric Analysis in Rabbits

Purpose: In vivo bone response was assessed by removal torque, hystological and histometrical analysis on a recently developed biomedical Ti‐15Mo alloy, after surface modification by laser beam irradiation, installed in the tibia of rabbits. Materials and Methods: A total of 32 wide cylindrical Ti‐15Mo dental implants were obtained (10 mm × 3.75 mm). The implants were divided into two groups: 1) control samples (Machined surface – MS) and 2) implants with their surface modified by Laser beam‐irradiation (Test samples – LS). Six implants of each surface were used for removal torque test and 10 of each surface for histological and histometrical analysis. The implants were placed in the tibial metaphyses of rabbits. Results: Average removal torque was 51.5 Ncm to MS and >90 Ncm to LS. Bone‐to‐implant‐contact percentage was significantly higher for LS implants both in the cortical and marrow regions. Conclusions: The present study demonstrated that laser treated Ti‐15Mo alloys are promising materials for biomedical application.     

Usefulness of cone‐beam CT in the evaluation of a spontaneously healed root fracture case

Horizontal root fractures (HRF) usually affect anterior teeth of male patients as a result of trauma. The consequences can be complex because of combined damage to different tissues, but it has been reported that root fractures undergo healing in majority cases. Diagnosis of HRF must be based on clinical findings, sensibility tests, and radiographic examination. The cone‐beam computed tomography (CBCT) has already been proven to be superior among other radiographic modalities for diagnostic imaging of root fractures. However, CBCT in these cases needs to be used in a careful manner, and only when the radiation exposure should be justified by the potential diagnostic benefits and improvement of the treatment results. This case report describes a case of spontaneously healed horizontal root fracture with displacement of the fragments and discusses the usefulness of CBCT in the follow‐up of root fractures cases.     

A survey of the first 6 years of experience with cone beam CT scanning in a teaching hospital orthodontic department

Abstract

Objective: Cone beam computed tomography (CBCT) is a specialized form of radiography and has been used in the Glasgow Dental Hospital since 2006. The clinical notes of all patients referred for CBCT from the orthodontic department between 2006 and 2011 were evaluated to determine the reasons for referral, scan parameters and clinical findings.

Design: Retrospective observational study.

Materials and methods: From a general database, the notes of patients from the Orthodontic Department of Glasgow Dental Hospital & School referred for CBCT imaging, since the inception of the service (2006 through to 2011) were examined. Information was obtained from CBCT request forms, case notes and radiology reports.

Results: During the chosen time period, 290 patients were referred for CBCT. Of these, 280 had clinical records that were available for investigation. Analysis showed approximately a third of scans were carried out within 4 weeks of referral. The smallest height of 4 cm was used for over a third of the scans investigated. Sixty-two per cent of the scans examined the maxilla only, 32% both jaws and 6% the mandible only. The two most common reasons for referral were to accurately determine the position of impacted teeth and to identify the presence of root resorption in relation to impacted teeth. In this cohort, 39% of teeth adjacent to an impacted tooth were found to have some root resorption, which closely supports the current literature.

Conclusions: This study provides a general overview of CBCT used by an orthodontic department in a teaching hospital environment.