A New Methodology to Determine the Orifice for Root Canal Configurations in First Permanent Molar Root and Canal Morphologies Using Micro-Computed Tomography.

BACKGROUND: The distinction between where the pulp chamber ends and the root canal system begins is poorly defined within the existing literature. METHODS: This paper aimed to describe a range of accurate methods to define the transition from pulp chamber to root canal in different first molar root morphologies using micro-focus computed tomography (micro-CT). METHODS: The sample consisted of 86 mandibular and 101 maxillary first molars from the skeletal collections housed in the Department of Anatomy and Histology of the Sefako Makgatho Health Sciences University and the Pretoria Bone Collection. A stepwise approach using the cemento-enamel junction (CEJ) and dedicated landmarks was followed to create an automated cross-sectional slice. RESULTS: Transition from pulp chamber to root canal could be accurately determined on maxillary and mandibular teeth. The occurrence of two separate roots in mandibular molars was 97.7%, with the remaining 2.3% having an additional disto-lingual root, with no mandibular molars displaying fused roots. In the maxillary molars, 92.1% had three separate roots and 7.9% displayed root fusion. Within this group, one tooth displayed a C-shaped root canal configuration and one a mesotaurodont-type morphology. CONCLUSION: The suggested methodology to determine orifice location was found to be appropriate in all morphological types.

Visualization Within the Ventricles of the Brain: A Micro-Focus X-Ray Study.

Conceptualization of the ventricular system of the brain by macroscopic studies is complicated by the lack of physical structure of these interconnected cavities. Dissection procedures designed to display the structures in the walls of the ventricles are destructive and not conducive for the appreciation of the ventricular system in its entirety. The application of Micro-focus X-ray tomography affords the possibility to appreciate hidden structures in a nondestructive manner. The aim of this study was to explore the possibility of using micro-focus X-ray tomography in the three-dimensional (3D) visualization of the ventricular system as well as the various neuroanatomical structures within its walls for educational purposes. Randomly selected embalmed human cadaver brains were scanned at Necsa (South African Nuclear Energy Corporation) housing the MIXRAD laboratory consisting of a Nikon XTH 225 ST micro-focus X-ray tomography facility. A 3D flythrough video of the ventricular system was reconstructed from these scans using software to view the inner surface of the ventricles. Micro-focus X-ray tomography provides feasible means of delivering high-resolution images in a nondestructive way to design a representation of the ventricular system. In addition, structures in the walls of the ventricular system could be appreciated in a novel way. It is envisaged that this 3D-fly-through video of the ventricular system will be valuable when integrated with standard prosections and atlas pictures in the educational setting. Further studies evaluating the use of this integrative visualization of the ventricular system of the brain for its applicability in the educational setting should be performed. Anat Rec, 301:1138-1147, 2018. © 2017 Wiley Periodicals, Inc.

The Pudendal Nerve and Its Branches in Relation to Richter's Procedure.

OBJECTIVE: Variations in the branching pattern of the pudendal nerve (PN) have been described in the literature. This study investigated these variations in order to comment on a safe area for the placement of a Richter's stitch. METHODS: Richter's procedure was performed on nine unembalmed female cadavers and followed by dissection. PN dissections were done on another 20 embalmed female cadavers. Variations in the branching pattern of the PN were noted and the distance between the Richter's stitch placed and the PN/or the inferior rectal nerve (IRN) measured. RESULTS: The IRN entered the gluteal region as a separate structure in 6/29 cases. The separate IRN was found to pass between 4.1 and 14.45 mm medial to the ischial spine in 18/29 cases. In one case, the Richter's stitch was found to pierce the IRN. The distance between the stitch and the PN and/or the IRN ranged from 0 to 17.8 mm. CONCLUSIONS: To minimize the risk of nerve damage or entrapment, the Richter's stitch should be placed >20 mm from the ischial spine. This recommended area should be revised for different population groups, as variations might exist between groups.

The midline mandibular lingual canal: importance in implant surgery.

PURPOSE: The study aims to determine if midline mandibular dental implants pose a risk for the midline lingual canal (MLC). MATERIALS AND METHODS: Cone beam computed tomography was used to scan 122 mandibles (31 black males; 28 black females; 32 white males and 31 white females). Midsagittal sections in the reconstructed images were made. A measurement of 6 mm across bucco-lingually was delineated as the minimum dimensions for implant placement. In dentate cases with a bucco-lingual distance in excess of 6 mm, the measurement was across the apex of the socket to determine the bone dimension available below the socket for implant placement. From these markers a vertical line was dropped to the MLC to measure the available bone. RESULTS: The MLC was a consistent finding. A statistical significant difference in bone availability among the sexes and dentition pattern was found, indicating that midline implants in edentulous females posed a risk of injury to the vessels of the MLC. CONCLUSION: Implants in the position of lower central incisors are regarded as a safe procedure. Clinicians should however take note of the position of the midline mandibular lingual canal and approach this area with caution, especially if the alveolar ridge is to be reduced before implant placement.