An Application Framework of Three-dimensional Reconstruction and Measurement for Endodontic Research Yuan Gao, DDS, PhD,* Ove A. Peters, DMD, MS, PhD, † Hongkun Wu, DDS, PhD,* and Xuedong Zhou, DDS, PhD* Abstract The purpose of this study was to customize an appli- cation framework by using the MeVisLab image pro- cessing and visualization platform for three-dimen- sional reconstruction and assessment of tooth and root canal morphology. One maxillary first molar was scanned before and after preparation with ProTaper by using micro–computed tomography. With a custom- ized application framework based on MeVisLab, in- ternal and external anatomy was reconstructed. Fur- thermore, the dimensions of root canal and radicular dentin were quantified, and effects of canal prepa- ration were assessed. Finally, a virtual preparation with risk analysis was performed to simulate the removal of a broken instrument. This application framework provided an economical platform and met current requirements of endodontic research. The broad-based use of high-quality free software and the resulting exchange of experience might help to improve the quality of endodontic research with micro– computed tomography. (J Endod 2009;35: 269 –274) Key Words Application framework, MeVisLab, micro-CT, morphol- ogy, root canal, 3D T he study of dental and root canal morphology is a critical theme in endodontic education, training, and treatment (1–7). To that end, three-dimensional (3D) reconstruction from high-resolution data is an increasingly popular and valuable method. It allows the evaluation of effects of root canal preparation and obturation; moreover, it allows assessing aspects of apical microleakage and cutting efficiency and has been used to establish finite element models (8 –14). Micro– computed tomography (micro-CT) data acquisition is nondestructive and allows fast examination of morphologic characteristics of a tooth in a detailed and accurate manner. At this point in time, generating a series of cross-sectional images of a tooth by using a micro-CT scanner is a common technique; however, image analysis and visualization techniques are core issues in the successful application of micro-CT data (15). A series of images generated by micro-CT can be visualized as a 3D structure only after performing a 3D reconstruction process (16). Therefore, 3D reconstruction software is indispensable. Currently, most micro-CT scanners are integrated with software that provides quantitative morphometric analysis of trabecular bone and reconstructed 3D images (17). Some of the software applications are available for SGI, Sun, and HP platforms and are relatively expensive and not widely used (18). A number of commercial software packages for 3D reconstruction with platforms applicable to PC-Windows have also been used to characterize tooth and root canal configuration, including 3D-Doctor, V-works, VGStudio Max, and Voxblast (7, 19 –21). These packages are typically expen- sive, and their availability to the general research community is limited. Moreover, most of the commercially available packages do not fulfill special functions needed for endodontic research, further diminishing the universal use of 3D reconstruction and micro-CT techniques in general. Recently, a highly developed software package has become freely available. MeVisLab (MeVis Research, Bremen, Germany) is a framework system for medical image processing and visualization platform for Windows XP (Microsoft Corp, Red- mond, WA); it provides an easy to learn modular visual programming interface with a comprehensive suite of image processing and visualization tools. The creation of a user-oriented application framework in MeVisLab is also quite time-consuming and is not an easy task for endodontic researchers (22). The purpose of this proof-of-principle study was to create a customized applica- tion framework by using MeVisLab for 3D reconstruction and assessment of tooth and canal morphology on the basis of micro-CT data. This framework should also serve to evaluate root canal preparation and perform advanced simulation and analyses includ- ing virtual canal preparation. Material and Methods Preparation of Specimen and Micro-CT Scanning One maxillary first molar that had been stored in thymol solution before usage was used for subsequent four framework application examples. The molar was accessed and prepared by manual ProTaper instruments (Dentsply Maillefer, Bal- laigues, Switzerland) according to the manufacturer’s guidelines. The palatal canal was prepared to F3, whereas mesiobuccal and distobuccal canals were prepared to F2. The tooth was scanned before and after preparation by using a micro-CT system (CT-80; Scanco Medical, Bassersdorf, Switzerland) with an isotropic voxel size of From the *State Key Laboratory of Oral Diseases, West China College & Hospital of Stomatology, Sichuan University, Chengdu, China; and † Department of Endodontics, Arthur A. Dugoni School of Dentistry, University of the Pacific, San Francisco, California. Address requests for reprints to Prof Xuedong Zhou, Pro- fessor and Dean, State Key Laboratory of Oral Diseases, West China College & Hospital of Stomatology, Sichuan University, 14, 3rd Section of RenMin Nan Road, Chengdu, China 610041. E-mail address: zhouxd@scu.edu.cn. 0099-2399/$0 - see front matter © 2008 Published by Elsevier Inc. on behalf of the Amer- ican Association of Endodontists. doi:10.1016/j.joen.2008.11.011 Basic Research—Technology JOE — Volume 35, Number 2, February 2009 Application Framework of 3D Reconstruction and Measurement for Endodontic Research 269