Effects of low-intensity pulsed ultrasound on healing of mandibular bone defects: an experimental study in rabbits.

Research evidence suggests that low-intensity pulsed ultrasound (LIPU) produces significant osteoinductive effects, accelerating the healing of bone defects. The authors investigated the effects of LIPU on mandibular bone defects in a rabbit model. Fifty-six adult Dutch rabbits were divided randomly into control, LIPU-1 (1MHz), and LIPU-3 (3MHz) groups. A mandibular defect was created in all rabbits. The effect of LIPU on mandibular defects was assessed by frequency (1 or 3MHz) and timing (2 and 4 weeks). Bone mineral density (BMD) was measured and stereology and histology performed; results were compared at the end of 2 and 4 weeks. LIPU-3 resulted in significantly higher bone formation compared to the control group at the end of week 4 on histological assessment (P=0.008). BMD was significantly higher at 4 weeks than at 2 weeks (P=0.03). LIPU-3 increased the numerical density of osteoblasts and osteocytes at the end of week 4 (P=0.05 and P=0.001, respectively). The results of this study are in favour of using LIPU 3MHz to accelerate mandibular bone healing. However, this study suggests that a frequency of 3MHz and the longer application of LIPU 3MHz for 4 weeks can only promote 8% mandibular bone healing in rabbits. Therefore, the use of LIPU has no really convincing, consistent clinical effects on maxillofacial bone healing.

Temporal bone pneumatisation: a computed tomography study of pneumatized articular tubercle.

AIM: To determine the prevalence and characteristics of pneumatized articular tubercle (PAT) at computed tomography (CT), and to determine whether the presence of PAT is a predictor of larger pneumatized spaces of temporal bone. MATERIALS AND METHODS: A retrospective study was performed using axial, sagittal and coronal CT images of 225 patients who attended a private medical imaging centre. Age and gender were recorded for all patients and, for cases of PAT, laterality and types were also recorded. Temporal bone pneumatization was recorded based on three reference structures on axial images. The Chi-square and Mann-Whitney U-tests were used. RESULTS: Of the 225 patients, 43 (9.55%) had PAT, of whom 24 were female and 19 were male. This difference was not statistically significant (p > 0.05). The age range of the patients with PAT was 8-67 years. Of the 43 patients, 24 had unilateral and 19 had bilateral PAT. Fifteen cases of PAT were unilocular and 28 were multilocular. Cases of PAT showed larger pneumatized spaces of other parts of the temporal bone (p = 0.0001). CONCLUSION: It is possible that PAT is a more frequent condition than is commonly perceived. The degree of pneumatization of temporal bone can be estimated by the evaluation of the air cells around the articular tubercle. CT is highly recommended in patients with PAT undergoing surgical treatment to determine the exact size and relationship of PAT to other parts of temporal bone.

Follicular ameloblastoma presenting as a sinonasal tumor.

A case of follicular ameloblastoma of the left maxilla in a 74-year-old man is reported. The tumor was presented as a radiographically solid mass filling the left sinonasal cavity and invaded maxillary alveola. After radical surgery, the patient has pursued a non-aggressive clinical course after 4 years of follow-up. The radiopathological features of this tumor were reviewed and the possibility of its sinonasal epithelium origin was discussed.

Multiple idiopathic apical root resorption: a case report.

The aim of this case report was to present a case of multiple idiopathic apical root resorption which is a rare condition in a 17-year-old adult male. External root resorption of the permanent teeth is a multifactorial process. Well-recognized causes of apical root resorption in permanent teeth include orthodontic therapy, trauma, periapical or periodontal inflammation, tumors, cysts, occlusal stress, impacted teeth, systemic conditions, endocrine imbalances and dietary habits. When none of these causes are present, it is termed idiopathic root resorption which may be either cervical or apical. Multiple idiopathic apical root resorption is a rare condition which is usually detected as an incidental radiographic finding. However, it may cause pain and mobility in severe cases.

Effect of magnetic resonance imaging on microleakage of amalgam restorations: an in vitro study.

OBJECTIVES: The technique of MRI, using powerful magnets, plays an important role in the diagnosis of diseases of the head and neck without any ionizing radiation. Because of the potential hazard imposed by the presence of ferromagnetic metals, patients with implanted metallic objects are excluded from MRI. However, amalgam restorations seem to be safe. The purpose of this study was to evaluate microleakage of amalgam restorations following MRI. METHODS: 63 human freshly extracted premolars were divided into 3 groups based on 3 high-copper amalgams used to restore standard class V preparations on both buccal and lingual surfaces. Three different amalgam materials were used: Cinalux, GS-80 and Vivacap. The teeth were transferred into saline solution for 2 months at room temperature and then sectioned mesiodistally. MRI was randomly applied to one half of each section, and the other half was kept as a control. Following MRI, all specimens were immersed in a dye solution, sectioned and scored for any microleakage using a stereomicroscope. RESULTS: Differences in microleakage within each group following MRI were significant in the GS-80 and Vivacap groups but not in the Cinalux group. However, there was no significant difference between the three groups regarding the microleakage score. CONCLUSIONS: The results of this study suggest that MRI is not a completely safe technique in patients with amalgam restorations. It was shown that the main effect of fields led to the appearance of thermoelectromagnetic convection, which is responsible for the enhancement of the diffusion process, grain boundary migration and vacancy formation resulting in microleakage.

Evaluation of carotid calcification detected using panoramic radiography and carotid Doppler sonography in patients with and without coronary artery disease.

OBJECTIVES: Carotid artery calcification is responsible for an estimated 5% of ischaemic strokes. Carotid doppler sonography (DS) is a frequently used non-invasive method for assessing carotid artery stenosis and calcification. This study assessed the utility of panoramic radiography to detect any carotid artery calcification in patients with and without coronary artery disease, as well as the level of agreement between panoramic radiographs and DS findings. METHODS: Ninety subjects who underwent coronary angiography for any reason in Namazi Hospital, Shiraz University of Medical Science during an 11 month period received a DS assessment and panoramic radiograph. The radiopacities adjacent to the cervical vertebrae at or below the intervertebral space between C3-C4 were diagnosed as carotid artery calcifications. Carotid calcifications were scored as present or absent and pattern of calcification was noted by a maxillofacial radiologist who was blind to the angiogram and sonogram results. The final sample population was 84 subjects, providing data on 168 carotid arteries. RESULTS: The panoramic radiograph had a sensitivity of 66.6% and a positive predictive value of 45% for detecting carotid artery calcifications in patients whose angiograms confirmed the coronary artery disease. It had 50% sensitivity in patients with normal angiogram. The level of agreement between panoramic radiographs and DS results was weak. CONCLUSION: Because of low sensitivity and positive predictive value, the panoramic radiograph can not be considered an accurate or reliable method for detecting carotid artery calcification.