Evaluation of the accuracy of linear measurements on multi-slice and cone beam computed tomography scans to detect the mandibular canal during bilateral sagittal split osteotomy of the mandible.

The aim of this study was to compare the accuracy of linear measurements of the distance between the mandibular cortical bone and the mandibular canal using 64-detector multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT). It was sought to evaluate the reliability of these examinations in detecting the mandibular canal for use in bilateral sagittal split osteotomy (BSSO) planning. Eight dry human mandibles were studied. Three sites, corresponding to the lingula, the angle, and the body of the mandible, were selected. After the CT scans had been obtained, the mandibles were sectioned and the bone segments measured to obtain the actual measurements. On analysis, no statistically significant difference was found between the measurements obtained through MSCT and CBCT, or when comparing the measurements from these scans with the actual measurements. It is concluded that the images obtained by CT scan, both 64-detector multi-slice and cone beam, can be used to obtain accurate linear measurements to locate the mandibular canal for preoperative planning of BSSO. The ability to correctly locate the mandibular canal during BSSO will reduce the occurrence of neurosensory disturbances in the postoperative period.

Use of digital panoramic radiography as an auxiliary means of low bone mineral density detection in post-menopausal women.

OBJECTIVES: To correlate the radiomorphometric indices obtained using digital panoramic radiography (DPR) with bone mineral densities, evaluated by the dual-energy X-ray absorptiometry test, in a population of post-menopausal females to identify patients with asymptomatic low bone mineral densities. METHODS: The morphology of the mandibular cortex was evaluated using the mandibular cortical index (MCI) and the inferior mandibular cortex width was evaluated using the mental index (MI) in 64 female patients who had undergone dual-energy X-ray absorptiometry assessment. Of these patients, 21 were diagnosed with osteopaenia and 20 with osteoporosis, and 23 were normal. Three new indices for evaluating the inferior mandibular cortex width were designed: the mental posterior index 1 (MPI1), MPI2 and MPI3. Statistical analyses were performed using the χ(2) and Kruskal-Wallis tests and the receiver operating characteristic curve. RESULTS: There were significant differences between the normal and lower bone mineral density groups (osteopaenia and osteoporosis) for MCI (p < 0.01). In the osteoporosis group, the MI, MPI1, MPI2 and MPI3 were significantly different from the normal and osteopaenia groups (p < 0.05). The MI, MPI1, MPI2 and MPI3 showed that there is an area in the mandibular cortex, located between the mental foramen and the antegonial region, which is valid for identifying females at high risk for osteoporosis. CONCLUSIONS: The MCI, MI, MPI1, MPI2, and MPI3 radiomorphometric indices evaluated using DPR can be used to identify post-menopausal females with low bone densities and to provide adequate medical treatment for them.

Anatomic variations of paranasal sinuses-clinical case report.

This article describes the clinical case of an 86-year-old female patient with an asymptomatic clinical condition, without presenting a history of previous traumatisms. When routine radiographic exam-panoramic radiograph-was performed, the following extensions of the paranasal sinuses were found: maxillary sinus (palate), sphenoid sinus (pterygoid process, major wing, and anterior clinoid process), and supraorbital portion of the frontal sinus. Thus computerized tomography was performed to confirm the diagnosis.

Comparison of transcranial radiograph and magnetic resonance imaging in the evaluation of mandibular condyle position.

OBJECTIVES: Several image modalities have been used to assess the condylar position in the glenoid fossa. However, despite the development of more advanced techniques for imaging the temporomandibular joint (TMJ), the transcranial projection remains widely used in dentistry. The purpose of this study was to compare the condylar position in transcranial radiography (TRANS) with MRI. METHODS: 70 matched pairs of TMJs (35 patients) who had undergone TRANS and MRI were evaluated. The TRANS scans were compared with the lateral, central and medial MRI scans, and the condylar position was assessed in the closed and open mouth position according to subjective and objective methods. The sensitivity, specificity and accuracy values were calculated for each group and Bowker's test was used to analyse the data. RESULTS: There was no statistical significance between TRANS and MRI (P > 0.05). However, even though there were similar mean values between them, the comparison with the lateral image showed higher values, which might be due to TRANS representing the lateral one-third of the condyle. CONCLUSIONS: It can be concluded that TRANS seems to be an acceptable method and its applicability as an adjunctive method in the condylar position should not be rejected.

Evaluation of temporomandibular joint in stress-free patients.

OBJECTIVES: The aetiology of temporomandibular disorders (TMD) is presently considered to be multifactorial, and stress has been regarded as an important factor in their onset. Many studies have evaluated the importance of stress in TMD; however, only patients with TMD and stress have been assessed. This study aimed at evaluating signs and symptoms of TMD in stress-free patients. METHODS: The temporomandibular joints (TMJs) of 40 stress-free patients were evaluated during clinical examination and in MRI. RESULTS: The individuals lived in an area without electric power supply or telephone services. They worked in agriculture and fishery. 77.5% of the patients presented normal mandibular function; 70% presented normal mandibular trajectory; 61.25% did not present sounds in TMJ and 93.75% did not present joint pain during palpation. Image screening showed that 70% of TMJ presented normal disc position. Only one patient (1.25%) presented TMD. CONCLUSIONS: The absence of stress is a strong factor for the non-development of TMD.

Tonsillolith--report of an unusual case.

Tonsilloliths are rare concretions found in the tonsillar crypt. They are usually single and unilateral, but occasionally may be multiple or bilateral. This report describes a case of a 47-year-old woman whose radiography revealed one radiopaque image located in the right ramus of the mandible. The patient revealed a history of slight dysphagia, halitosis and swallowing pain with a foreign body sensation. Her medical history revealed a tonsillectomy when she was eight years old and the removal of the uvula because of sleep apnoea six years ago. Computer tomography showed a delimited and calcified oval image measuring 0.6 x 0.6 cm. The tonsillar concretion might have been formed because of a calcification of the lymphoid tissue. On the patient's request, surgical excision was not performed and she will be monitored due to the tendency of such lesions to grow.

Pneumatization of the sphenoid sinus.

This paper describes a case of pneumatization of the sphenoid sinus in the pterygoid process and greater wing of the sphenoid bone, observed on a panoramic radiograph. Conventional radiographs and computerized tomography in axial and coronal sections confirmed the presence of the pneumatization of these structures.