This study found a higher prevalence of patients with maxillary sinus septa than what has been reported previously. This may be due to the exact nature of the CT software and the ease of use of the 3D reconstruction for identification of septa. Another explanation could be that all septa that were visible on the 3D reconstruction were included and there was no minimum cut-off height. No significant differences were found between edentulous and dentate patients.
2Running title: Implants near the midline mandibular lingual canal Abstract Purpose: To determine the position and occurrence of the midline mandibular canal (MLC) in the various age, sex, population and dentition groups. The average distances from the MLC to a planned mandibular midline implant and the inferior mandibular border were measured. Materials and methods: Cone beam computed tomography (CBCT) 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 of edentulous mandibles or sagittal sections through the socket of the 41 tooth (FDI nomenclature) in dentate mandibles were made. A measurement of 6 mm across buccolingually (BL) was delineated with the caliper tool indicating the minimum dimensions for placement of an implant. In dentate cases where the BL distance was in excess of 6 mm, the caliper was placed across the deepest part of the socket as a marker 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 within the anterior mandible.A statistical significant difference in bone availability amongst the sexes and with dentition pattern was found indicating that edentulous female patients were particularly at risk of injury to the vessels of the midline lingual canal during implants in that area. Conclusion: Immediate implants in the position of lower central incisors are regarded as a safe procedure as is the placement of interforaminal implants in the anterior mandible. 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.
Oral leukoplakia and other potentially malignant disorders (PMD) may progress to oral squamous cell carcinoma (OSCC). The gold standard for assessing the potential for malignant transformation remains histologic examination with the aim of grading the dysplastic changes. However, not all lesions with dysplasia will progress to OSCC. DNA ploidy has been suggested as a method to predict the clinical behaviour of PMD. This study reports on the use of high-resolution flow cytometry to determine the ploidy status of formalin-fixed, paraffin-embedded material from PMD compared to their dysplasia grade on histology. Aneuploidy was found in 13 % of mild, 31 % of moderate, and 54 % of severe dysplasia cases. This difference was statistically significant (p = 0.011). The differences in ploidy status were more significant when grouping the dysplasia into low-risk and high-risk categories (p = 0.008). These findings indicate that the ploidy status of PMD as determined by high-resolution flow cytometry may be of value in predicting biological behaviour in PMD such as leukoplakia.
The greater palatine foramen (GPF) is an important anatomical landmark and has substantial clinical relevance in dental surgery. Knowledge of its precise location and dimensions is required for proper planning of surgical procedures involving the posterior maxilla. We used microfocus computed tomography to determine the location and dimensions of the GPF, and any sex and race variations in those measurements, in 77 human skulls scanned at the South African Nuclear Energy Corporation. Specialized software was used for three-dimensional rendering, segmentation, and visualization of the reconstructed volume data. GPF location ranged from adjacent to the first molar to distal of the third molar. The most common GPF location was near the third molar (66.7% of skulls), and the GPF was as close as 6.31 mm (mean distance 12.75 ± 3 mm). The mean GPF dimensions were 5.22 mm on the anterior-posterior axis and 2.81 mm on the lateral-medial axis. We noted no significant differences in relation to race, sex, or age in the sample. The GPF was adjacent or posterior to the third maxillary molar in most skulls.
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