动态导航技术应用于引导牙髓治疗领域的研究进展

近年来,随着口腔数字化技术的发展与锥形束CT(cone beam computed tomography, CBCT)、口内扫描等数据获取方法的普及,以计算机辅助静态导板（static template）与动态导航（dynamic navigation）为代表的引导牙髓治疗技术（guided endodontics）,逐渐应用于微创开髓、钙化根管定位、去除纤维桩、显微根尖外科手术等领域,在提高治疗效率、精准性与成功率,减少组织损失量与医源性失误等方面发挥出独特优势,其中动态导航技术具有实时、可视化、术中可调整的特点,已成为目前引导牙髓治疗新的发展方向。本文将对目前动态导航在引导牙髓治疗领域的体外研究与临床应用进展做一综述,总结目前动态导航的应用优势与不足,为今后的临床推广应用提供参考。     

动静态导航技术在牙髓根尖周病治疗中的应用及展望

根管治疗及根尖手术是处理牙髓根尖周病的常规方法。相比裸眼操作,口腔手术显微镜的普及和应用有效提高了治疗精准度及预后。然而,在面临严重根管钙化、根尖周病损定位困难或毗邻重要解剖结构等复杂情况时,即使经验丰富的术者在进行显微牙髓治疗的过程中也存在风险因素。近年来,随着数字化信息技术的快速发展,动静态导航技术为应对疑难复杂牙髓根尖周病提供了行之有效的治疗新模式,即通过锥形束CT拍摄、口内扫描、结合导航软件设计手术虚拟入路,继而在三维打印导板或实时导航设备的辅助下进行精准根管治疗或根尖手术。本文对导航牙髓治疗的分类、特点以及国内外临床应用现状进行了系统阐述。     

数字化导航技术在牙髓病学领域的研究进展

随着数字化导航技术在口腔种植领域的广泛应用,不少学者已将数字化导航技术用于治疗疑难复杂的牙髓及根尖周病,如疏通钙化根管、建立髓腔通路、定位根尖手术位点等。与传统方法相比,在导航系统的辅助下,临床操作更加精准、高效、安全、微创。本文就近年来数字化导航技术在牙髓及根尖周病领域的应用现状及发展趋势作一阐述。     

动静态导航技术在牙髓根尖周病治疗中的应用及展望

根管治疗及根尖手术是处理牙髓根尖周病的常规方法。相比裸眼操作, 口腔手术显微镜的普及和应用有效提高了治疗精准度及预后。然而, 在面临严重根管钙化、根尖周病损定位困难或毗邻重要解剖结构等复杂情况时, 即使经验丰富的术者在进行显微牙髓治疗的过程中也存在风险因素。近年来, 随着数字化信息技术的快速发展, 动静态导航技术为应对疑难复杂牙髓根尖周病提供了行之有效的治疗新模式, 即通过锥形束CT拍摄、口内扫描、结合导航软件设计手术虚拟入路, 继而在三维打印导板或实时导航设备的辅助下进行精准根管治疗或根尖手术。本文对导航牙髓治疗的分类、特点以及国内外临床应用现状进行了系统阐述。     

手术显微镜在牙髓治疗中的应用

牙髓治疗中手术显微镜的应用主要包括根管治疗、根管再治疗和牙髓外科。在显微镜放大的视野下，能够定位隐蔽根管、发现微裂、辨别髓室底和周围的牙本质、识别峡区及根管系统的细微结构，对根管治疗的成功至关重要^[1]。医生可以在显微镜下清楚地观察到根管内的情况，避免了操作上的盲目性，过去一些困难病例如：     

氢氧化钙在牙体牙髓疾病治疗中的临床研究现状

氢氧化钙具有稳定的理化性能,大量的实验室和临床研究表明：氢氧化钙具有抑制根管内细菌生长、促进根尖形成及根尖周缺损组织重建等优点.本文就氢氧化钙的特性及其在牙体牙髓疾病治疗中的临床应用研究现状进行综述.     

牙体牙髓临床治疗Ⅲ.可视化根管技术

传统的根管治疗技术主要通过手的感觉、冲洗液的颜色以及切削出的牙本质来确定根管预备的效果。由于根管形态的复杂性以及肉眼条件下根管的不可见性，根管清理和充填的质量难以保证，且创伤较大。近年来，手术显微镜和内镜被用于牙髓病和根尖周病的诊断和治疗，术者可以直接观察根管的细微结构，确认手术位置，减少治疗的不确定性，显著提高了牙髓病和根尖周病治疗的品质。     

Accuracy and Efficiency of a Dynamic Navigation System for Locating Calcified Canals

IntroductionCalcified canals present a challenge during endodontic treatments. The purpose of this study was to compare the accuracy and efficiency of a dynamic navigation system (DNS) to the freehand (FH) method for locating calcified canals in human teeth.MethodsSixty human single-rooted teeth with canal obliteration were selected and mounted in dry cadaver jaws. Based on cone-beam computed tomographic scans of the jaws, the drilling path and depth were virtually planned to use X-Guide software (X-Nav Technologies, LLC, Lansdale, PA). Access preparation was made with navigation in the DNS group and without guidance in the FH group by 2 operators with different levels of experience. Postoperative cone-beam computed tomographic scans were taken of all teeth. Linear and angular deviations and reduced dentin thickness at 2 levels were measured. The time for locating the canal, the number of mishaps, and the unsuccessful attempts were determined and analyzed.ResultsThe mean linear and angular deviations, reduced dentin thickness (at both levels), the time for access cavity preparation, and the number of mishaps in the DNS group were significantly less than the FH group (P ≤ .05). The unsuccessful attempts were not different between the 2 groups (P > .05). The time for access preparation was significantly shorter for the board-certified endodontist in the FH group (P ≤ .05).ConclusionsThe DNS was more accurate and more efficient than the FH technique in locating calcified canals in human teeth. This novel DNS can help clinicians avoid catastrophic mishaps during access preparation in calcified teeth.     

Real-Time Guided Endodontics with a Miniaturized Dynamic Navigation System Versus Conventional Freehand Endodontic Access Cavity Preparation: Substance Loss and Procedure Time

IntroductionThis study aimed to evaluate substance loss and the time required for access cavity preparation (ACP) using the conventional freehand method (CONV) versus a miniaturized dynamic navigation system of real-time guided endodontics (RTGE) in an in vitro model using 3-dimensional–printed teeth.MethodsNine human anterior maxillary teeth were selected and micro–computed tomographic scanned. Root canals were virtually reduced to 2 mm below the cementoenamel junction. The teeth were digitally duplicated and mirrored to yield 6 different models with 6 single-rooted teeth each. The models were 3-dimensionally printed using radiopaque resin and consecutively mounted on a dental mannequin for ACP. Two operators with 12 and 2 years of clinical experience, respectively, received 6 models (36 teeth) each and performed ACP on half of the models using RTGE (after digital planning) and CONV on the other half 2 weeks later. The time was recorded. Postoperative substance loss was measured by cone-beam computed tomographic imaging. The differences in time and substance loss between the methods and operators were evaluated by the t test.ResultsOverall, substance loss was significantly lower with RTGE than CONV (mean = 10.5 mm³ vs 29.7 mm³), but both procedures took a similar time per tooth (mean = 195 vs 193 seconds). Operator 1 (more experienced) achieved significantly less substance loss than operator 2 with CONV (mean = 19.9 vs 39.4 mm³) but not with RTGE (mean = 10.3 vs 10.6 mm³).ConclusionsRTGE is a practicable, substance-sparing method performed in comparable time as CONV. Moreover, RTGE seems to be independent of operator experience.     

13例老年人髓室底穿通患牙治疗的临床报告

目的:探讨老年人髓室底穿通患牙的治疗效果.方法:对13例老年人髓室底穿通的病人进行临床分析,探讨临床治疗方法.结果:13例髓室底穿通患牙中,经平均2年随诊观察,3例拔除,10例使用良好.结论:老年人髓室底穿通患牙也可通过治疗保留,以恢复咀嚼功能.     

再论磨牙髓腔解剖研究及临床意义

目的：恒磨牙髓腔解剖的再研究。方法：通过开髓、根管预备，测量扩大针进入根管角度和根管长度，冠颈横断观察。结果：髓室底形态有４型；根管口分布类型：上颌磨牙有２类５型，下颌磨牙有３类４型；扩大针进入根管角度及根管长度因根而异。结论：成功地进行牙髓、尖周病的治疗，熟悉髓腔解剖十分重要。     

Studies on Mineralized Dental Tissues: III. Dental changes in a case of osteopetrosis

Abstract

Aim. The purpose of this study was to investigate the scanning and segmentation precision of surface models of molars for the detection of small volumes, such as the reduced pulp cavity; formation of mineral deposits; detection of narrow root canals and to improve the clinical and morphological understanding of the number of root canals and their configuration. Methods. Eighteen human molars were scanned using X-ray micro-computed tomography. The reconstruction of the surface models had a precision of <1 voxel, using three-dimensional software and quantitative color mapping. In order to relate the measurements to changes over time the size of the pulp chambers was classified in two well-defined groups. Results. The mineral deposits were more evenly distributed in small pulp chambers than in large, but complete root canal calcification was never observed. No difference was observed in the material with respect to the presence of intra-radicular connections. In upper molars, a second mesiobuccal canal (mb₂) frequency of 91% was found. The difference in length between the first mesiobuccal canal (mb₁) and mb₂ was <1 mm. The number of root canals could be related to the number of root cones. Conclusion. In summary, three-dimensional surface models were made with a high precision; an increased accumulation of mineral deposits was noted in molars with small pulp chambers and combined with the consistent pattern of intra-radicular connections, the potential endodontic treatment complexity is underlined in such cases. Finally, an improved understanding of root canal prevalence was reached, when merging well-defined definitions on root morphology and clinical classification systems.     

3-Dimensional Accuracy of Dynamic Navigation Technology in Locating Calcified Canals

IntroductionThis study aimed to present a novel dynamic navigation method to attain minimally invasive access cavity preparations and to evaluate its 3-dimensional (3D) accuracy in locating highly difficult simulated calcified canals among maxillary and mandibular teeth.MethodsThree identical sets of maxillary and mandibular 3D-printed jaw models composed of 84 teeth in their anatomic locations with simulated calcified canals (N = 138 canals) were set up on dental manikins. The Navident dynamic navigation system (ClaroNav, Toronto, Ontario, Canada) was used to plan and execute access preparations randomly with high-speed drills by a board-certified Endodontist. Two-dimensional (2D) and 3D horizontal, vertical, and angulation discrepancies between the planned and placed access preparations were digitally measured using superimposed cone-beam computed tomographic scans. Analysis of covariance models were used to evaluate the associations and the interaction between tooth type and jaw, the canal orifice depth, and the discrepancies between planned and prepared access cavities. The significance level was set at .05.ResultsThe mean 2D horizontal deviation from the canal orifice was 0.9 mm, and it was significantly higher on maxillary compared with mandibular teeth (P < .05). The mean 3D deviation from the canal orifice was 1.3 mm, and it was marginally higher on maxillary teeth in comparison with mandibular teeth (P ≥ .05). The mean 3D angular deviation was 1.7 degrees, and it was significantly higher in molars compared with premolars (P < .05). The 3D and 2D discrepancies were independent of the canal orifice depths (P > .05). The average drilling time was 57.8 seconds with significant dependence on the canal orifice depth, tooth type, and jaw (P < .05).ConclusionsThis study shows the potential of applying dynamic 3D navigation technology with high-speed drills to preserve tooth structure and accurately locate root canals in teeth with pulp canal obliteration.     

干髓术失败患牙的根管再治疗

目的:通过对干髓术失败患牙进行根管再治疗,探讨此类病例的特点及再治疗方法.方法:选取干髓术失败的磨牙63个,采用小号K锉配合次氯酸钠溶液和EDTA溶液探查根管并清理根管内的感染物质,封入氢氧化钙糊剂1～2周,采用机动镍钛器械Hero642进行根管预备,侧向加压技术充填根管,记录治疗过程中患牙症状的改善程度,根管疏通情况,根管预备和充填的效果.结果:62个患牙的根管疏通成功,治疗过程中症状明显缓解或完全消失,瘘管明显减小或消失,根管预备时无根管偏移、根尖阻塞、台阶等并发症发生,根管形态良好.结论:干髓术失败患牙在根管治疗时强调彻底清除根管内的感染物质,采用次氯酸钠和EDTA溶液清理根管,氢氧化钙消毒根管,机用镍钛器械进行根管预备能取得良好的治疗效果.     

不同年龄下颌第一前磨牙髓腔直径的测量观察

目的:观察下颌第一前磨牙髓腔直径的增龄变化。方法:对80颗年龄明确,外形完整的下颌第一前磨牙的X线图像进行定点测量髓腔近远中径和颊舌径,统计髓腔直径的平均值。结果:髓腔直径随年龄增大而逐渐减小。结论:不同年龄下颌第一前磨牙髓腔均呈"扁漏斗状",不利于根管预备中导入器械的旋转;通过测量髓腔直径,为法医学和考古学推测个体年龄提供参考。