Comparison of alternative image reformatting techniques in micro-computed tomography and tooth clearing for detailed canal morphology.

INTRODUCTION: Micro-computed tomography (MCT) shows detailed root canal morphology that is not seen with traditional tooth clearing. However, alternative image reformatting techniques in MCT involving 2-dimensional (2D) minimum intensity projection (MinIP) and 3-dimensional (3D) volume-rendering reconstruction have not been directly compared with clearing. The aim was to compare alternative image reformatting techniques in MCT with tooth clearing on the mesiobuccal (MB) root of maxillary first molars. METHODS: Eighteen maxillary first molar MB roots were scanned, and 2D MinIP and 3D volume-rendered images were reconstructed. Subsequently, the same MB roots were processed by traditional tooth clearing. Images from 2D, 3D, 2D + 3D, and clearing techniques were assessed by 4 endodontists to classify canal configuration and to identify fine anatomic structures such as accessory canals, intercanal communications, and loops. RESULTS: All image reformatting techniques in MCT showed detailed configurations and numerous fine structures, such that none were classified as simple type I or II canals; several were classified as types III and IV according to Weine classification or types IV, V, and VI according to Vertucci; and most were nonclassifiable because of their complexity. The clearing images showed less detail, few fine structures, and numerous type I canals. Classification of canal configuration was in 100% intraobserver agreement for all 18 roots visualized by any of the image reformatting techniques in MCT but for only 4 roots (22.2%) classified according to Weine and 6 (33.3%) classified according to Vertucci, when using the clearing technique. CONCLUSIONS: The combination of 2D MinIP and 3D volume-rendered images showed the most detailed canal morphology and fine anatomic structures.

Three-dimensional analysis of maxillary first molar mesiobuccal root canal configuration and curvature using micro-computed tomography.

OBJECTIVE: The complex anatomic configuration of the maxillary first molar mesiobuccal (MB) root canal system has been the subject of several studies. The purpose of this investigation was to analyze the 3-dimensional (3D) characteristics of the maxillary first molar MB canal system using micro-computed tomography (microCT). STUDY DESIGN: Extracted maxillary first molars (46) were scanned by microCT and their canals reconstructed by 3D modeling software. RESULTS: In these MB roots, nearly two-thirds (65.2%) had 2 canals, fewer than one-third (28.3%) had only 1 canal, and a few (6.5%) had 3 canals. The most common root canal configuration was 2 distinct canals (type III: 37.0%), followed by 1 single canal (type I: 28.3%), 2 canals that joined together (type II: 17.4%), 1 canal that split into 2 (type IV: 10.9%), and 3 canals (type V: 6.5%). CONCLUSION: MicroCT provided an in-depth analysis of canal configurations, as well as length, curvature, and location of calcified segments.

Quantitative three-dimensional analysis of root canal curvature in maxillary first molars using micro-computed tomography.

In endodontic therapy, access and instrumentation are strongly affected by root canal curvature. However, the few studies that have actually measured curvature are mostly from two-dimensional radiographs. The purpose of this study was to measure the three-dimensional (3D) canal curvature in maxillary first molars using micro-computed tomography (microCT) and mathematical modeling. Extracted maxillary first molars (46) were scanned by microCT (502 image slices/tooth, 1024 X 1024 pixels, voxel size of 19.5 x 19.5 x 39.0 microm) and their canals reconstructed by 3D modeling software. The intersection of major and minor axes in the canal space of each image slice were connected to create an imaginary central axis for each canal. The radius of curvature of the tangential circle was measured and inverted as a measure of curvature using custom-made mathematical modeling software. Root canal curvature was greatest in the apical third and least in the middle third for all canals. The greatest curvatures were in the mesiobuccal (MB) canal (0.76 +/- 0.48 mm(-1)) with abrupt curves, and the least curvatures were in the palatal (P) canal (0.38 +/- 0.34 mm(-1)) with a gradual curve. This study has measured the 3D curvature of root canals in maxillary first molars and reinforced the value of microCT with mathematical modeling.

A multi-layered application for the gross description using Semantic Web technology.

OBJECTIVE: Development of a Semantic Web technology based system for the formalization of the gross description. METHOD: A system is developed using the Java-2 platform. It is based on a light-weight version of the Galen top level ontology. Web technologies like XML, SAX en DOM have been used. RESULT: Three system components have been developed to support the semantic, the object and the syntax layers of the PathOnt architecture. CONCLUSION: The PathOnt approach provides a tool for the communication among clinicians and technicians involved in pathology examinations. This tool also provides a foundation for linking the specimen-specific data with the controlled medical ontology so that the stored information can be used in different circumstances.