Nao Wakasugi-Sato

Relationship Between Inferior Alveolar Nerve Canal Position at Mandibular Second Molar in Patients With Prognathism and Possible Occurrence of Neurosensory Disturbance After Sagittal Split Ramus Osteotomy

PURPOSE To elucidate the relationship between the anatomic position of the inferior alveolar nerve (IAN) at the mandibular second molar and the occurrence of neurosensory disturbances of the IAN after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Also, the present study evaluated the difference in anatomic position of the IAN between patients with and without mandibular prognathism. PATIENTS AND METHODS Computed tomography images were taken of 28 patients with mandibular prognathism and 30 without prognathism. On these scans, the IANs from the mandibular second molar region to the mandibular foramen in the mandibular ramus were identified. The present study was designed as a cross-sectional study. The distance from the buccal aspect of the IAN canal to the outer buccal cortical margin of the mandible in the mandibular second molar regions was measured on the computed tomography images. Also, the linear distance between the superior aspect of the IAN canal and the alveolar crest in these regions was calculated. In addition, we investigated the presence or absence of contact between the IAN canal and the inner buccal cortical margin of the mandible from the mandibular second molar to the mandibular foramen in the mandibular ramus. Next, we examined whether neurosensory disturbances occurring after SSRO were related to the position of the IAN at the mandibular second molar. RESULTS A significant difference was found in the occurrence of neurosensory disturbances of the IAN after SSRO between men and women (χ(2) test, P < .05). For the distance from the buccal aspect of the IAN canal to the outer buccal cortical margin of the mandible in the mandibular second molar region, a significant difference was found between groups with and without neurosensory disturbances (Students t test, P < .01). The shorter the distance from the buccal aspect of the IAN canal to the outer buccal cortical margin, the more frequent the occurrence of neurosensory disturbances of the IAN. CONCLUSIONS The present results have demonstrated that gender and the anatomic position of the IAN canal at the mandibular second molar are significantly related to the occurrence of neurosensory disturbances of the IAN after SSRO. Therefore, surgeons should clearly inform patients of the increased possibility of neurosensory disturbances after SSRO when the patients are female and are found to have a shorter distance from the buccal aspect of the IAN canal to the outer buccal cortical margin.

Advanced Clinical Usefulness of Ultrasonography for Diseases in Oral and Maxillofacial Regions

Various kinds of diseases may be found in the oral and maxillofacial regions and various modalities may be applied for their diagnosis, including intra-oral radiography, panoramic radiography, ultrasonography, computed tomography, magnetic resonance imaging, and nuclear medicine methods such as positron emission tomography. Of these modalities, ultrasound imaging is easy to use for the detection of noninvasive and soft tissue-related diseases. Doppler ultrasound images taken in the B-mode can provide vascular information associated with the morphology of soft tissues. Thus, ultrasound imaging plays an important role in confirming the diagnosis of many kinds of diseases in such oral and maxillofacial regions as the tongue, lymph nodes, salivary glands, and masticatory muscles. In the present article, we introduce three new applications of ultrasonography: guided fine-needle aspiration, measurement of tongue cancer thickness, and diagnosis of metastasis to cervical lymph nodes.

Correlation of mandibular bone quality with neurosensory disturbance after sagittal split ramus osteotomy

Our aim was to find out whether the quality of bone around the inferior alveolar nerve is correlated with neurosensory disturbance to the nerve after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. Computed tomograms (CT) were taken of 35 patients with mandibular prognathism and 35 without. To assess the density of bone around the inferior alveolar nerve, the width of the buccal cortical bone in the mandibular second molar regions was measured on CT. The Hounsfield units (HU) in the same regions were also measured. The number of HU in the mandible around the second molar regions was significantly higher (p<0.01) in those with neurosensory disturbance (p<0.01). The quality of bone measured by HU is associated with an increased risk of neurosensory disturbance, but the width of buccal bone is not.

Assessment of the relationship between the mandibular cortex on panoramic radiographs and the risk of bone fracture and vascular disease in 80-year-olds

OBJECTIVES The objective of this study was to assess cortical measurements on panoramic radiographs in 80-year-old subjects to predict bone fracture and vascular disease risks. METHODS The cortical width and shape (normal cortex, mildly to moderately eroded cortex, and severely eroded cortex) were evaluated on 659 panoramic radiographs obtained from 262 men and 397 women, all of whom were 80 years old. At baseline, a general medical examination, including heel bone density, was performed in all subjects. Fractures and vascular disease occurring within 5 years after the baseline examination were determined in 191 subjects and in 108 subjects who died within 5 years after the baseline examination. RESULTS There were significant correlations between heel bone density and cortical width (r = 0.435, P < .001) and shape (r = 0.231, P < .001). However, cortical measurements on panoramic radiographs were not significantly associated with the occurrence of fractures and vascular disease within 5 years after the baseline examination. CONCLUSIONS Among the elderly, cortical measurements on panoramic radiographs may be associated with bone mineral density and physical activity, but they are not useful markers for the subsequent occurrence of fractures and vascular disease.

Dynamic magnetic resonance sialography for patients with xerostomia.

OBJECTIVE The aim was to evaluate the utility of dynamic magnetic resonance (MR) sialographic images as a diagnostic tool for patients with xerostomia as chief complaint. METHODS Various parameters of dynamic MR sialographic images from 40 healthy volunteers were compared with those from 28 patients having dry mouth as chief complaint. Dynamic MR sialographic images were acquired using a 1.5-T full-body MR system and 2-dimensional fast asymmetric spin-echo (2D-FASE) sequences. Acquisition of the optimal section using 2D-FASE sequencing with single-section acquisition of thick sections was repeated every 30 s before and after a few drops of 5% citric acid was placed on the tongue. Student t test was used to examine differences between the healthy volunteer and patient groups regarding the maximum area of salivary gland ducts before and after citric acid stimulation. RESULTS The maximum area of the detectable ducts in the patient group was significantly smaller (P < 0.001), whereas the change in detectable duct area was significantly lower (P < 0.001). CONCLUSIONS This study suggests that dynamic MR sialographic images and data can be useful in the diagnosis of patients with dry mouth as chief complaint.

Relationship between the curative effects of carbamazepine administration and the neurovascular compression volume of the trigeminal nerve measured using magnetic resonance cisternography.

ObjectivesTo elucidate the relationship between the extent of pain and neurovascular compression (NVC) volume, measured by magnetic resonance (MR) cisternography, in patients with trigeminal neuralgia. In addition, we aimed to evaluate the relationship between NVC volume and the efficacy of carbamazepine administration in patients with trigeminal neuralgia. MethodsMR cisternography was performed on 214 patients with clinical signs and symptoms that suggested trigeminal neuralgia retrospectively. The extent of their pain was evaluated using visual analog scales. Next, only carbamazepine was administered as the initial treatment. For the patients with NVC detectable on MR cisternography, the relationship between the extent or nature of the pain and the neurovascular volume was analyzed. In addition, the correlation between the efficacy of carbamazepine treatment and the NVC volume was evaluated retrospectively. ResultsOf the 214 patients evaluated, 144 were deemed to have NVC. In these 144 patients, a significant difference was found between the NVC volume and the curative effects of 100 mg/d carbamazepine. However, no significant correlation was found between the extents of pain by visual analog score or between the daily dosage of carbamazepine and the NVC volume measured by MR cisternography. ConclusionsThree-dimensional MR cisternography is very useful for detecting the site of NVC in patients with trigeminal neuralgia. NVC measured by this technique may indicate the prognosis after initial treatment. The present results suggest that the evaluation of NVC volume by MR cisternography would be useful in choosing the initial treatment for patients with trigeminal neuralgia.

Intraperitoneal injection of pilocarpine activates neurons in the circumventricular organs and hypothalamus in rats

It has been suggested that while the sialogogue pilocarpine elicits salivary secretion by acting directly on acinar cells of the salivary glands, it induces drinking behavior by acting on muscarinic receptors in the central nervous system. To study which brain regions are affected by the peripherally injected pilocarpine, we investigated changes in the numbers of c-Fos immunoreactive cells. The injections increased the numbers of c-Fos immunoreactive cells in the subfornical organ, median nucleus of preoptic area, organum vasculosum of lamina terminalis, paraventricular nucleus and supraoptic nucleus. Intracerebroventricular injection of pilocarpine produced similar changes in the expression of c-Fos immunoreactivity. The increases in immunoreactive expression induced by both the intraperitoneally and intracerebroventricularly injected pilocarpine were suppressed by previous intracerebroventricular injection of the muscarinic receptor antagonist atropine. Electrophysiological experiments using slice preparations and whole cell recordings showed that pilocarpine depolarized the membrane of neurons in the subfornical organ and suppressed the inhibitory GABAergic synaptic currents by a presynaptic action. The results suggest that peripherally applied pilocarpine does not act only on the salivary glands as a sialogogue, but also evokes thirst sensation by acting on the center controlling body fluid balance in the central nervous system.

Reflection of 18F-FDG accumulation in the evaluation of the extent of periapical or periodontal inflammation

OBJECTIVES To elucidate whether fluorine-18-labeled ((18)F) fluoro-2-deoxy-d-glucose (FDG) accumulation can reflect the extent of periodontal inflammation, periapical inflammation, or dental caries. STUDY DESIGN (18)F-FDG accumulations on positron emission tomography (PET)-computed tomography (CT) were retrospectively compared with the size of the bone resorption areas caused by periodontal inflammation, periapical inflammation, or dental caries on panoramic radiographs, CT, and magnetic resonance imaging (MRI) in 44 subjects. RESULTS A significant correlation was found between the size of the bone resorption area caused by periodontal (r = 0.595, P < .01) or periapical (r = 0.560, P < .01) inflammation and the highest standardized uptake value (SUVmax) of (18)F-FDG accumulation. A significant correlation was found between the periodontal (r = 0.622, P < .01) or periapical (r = 0.394, P < .01) inflammatory findings on MRI and the SUVmax of (18)F-FDG accumulation. The SUVmax of (18)F-FDG around most teeth with caries was under 1.5. CONCLUSIONS (18)F-FDG accumulation reflects the extent of dental inflammation, not dental caries.

Distinct effects of cevimeline and pilocarpine on salivary mechanisms, cardiovascular response and thirst sensation in rats

OBJECTIVE Cevimeline and pilocarpine (muscarinic receptor agonists) are used as sialogogues in xerostomia treatment. It is important to know the different effects on their salivary mechanisms and the side effects. The aim of the present study was to clarify and compare the comprehensive effects of cevimeline to pilocarpine on salivary, cardiovascular and central mechanisms in rats. DESIGN Under anaesthesia, whole saliva secretion, parotid blood flow and blood pressure were measured following intra-peritoneal administrations of the sialogogues. In digested parotid cells, intracellular Ca(2+) concentrations were measured after the sialogogue application. In the conscious condition, changes in angiotensin II-induced water intake were observed after cevimeline administration. In the subfornical organ, which is a thirst-related central nucleus, the effect of cevimeline on the neuronal activity was electrophysiologically investigated. RESULTS Cevimeline at 80μmolkg(-1) showed slowly increasing and lasting salivation, a similar blood flow increment in the parotid gland and higher pressor response when compared to pilocarpine at 4μmolkg(-1). In parotid cells, cevimeline increased the intracellular Ca(2+) concentration in a similar manner to pilocarpine, but at a higher concentration than pilocarpine. Cevimeline inhibited angiotensin II-induced water intake and neuronal activity in the subfornical organ, which is in contrast to reported effects of pilocarpine. CONCLUSIONS Cevimeline activates common salivary mechanism with pilocarpine but has a slower onset of activation, longer duration of salivation and an increased pressor response at higher doses. The anti-dipsogenic effect of cevimeline is due to the inhibitory neuronal effect on the thirst-related central nuclei.

Diagnostic significance of characteristic findings on ultrasonography for the stitch abscess after surgery in patients with oral squamous cell carcinoma

To elucidate the clinical significance of imaging modalities for detection of stitch abscess after surgery in patients with oral squamous cell carcinoma (SCC). In 137 patients with oral SCC suspected of having lymph node metastases, local recurrence of tumor, or stitch abscess after surgery, the characteristic imaging findings related to lymph node metastases, local recurrence of tumor, and stitch abscess on ultrasonography (US), computed tomography (CT), magnetic resonance (MR), and (18)fluorodeoxyglucose (18FDG)-positron emission tomography (PET) images were identified and analyzed. In all six patients with stitch abscess, characteristic findings were demonstrated on US, different from those of metastatic lymph nodes and local recurrence on CT, MRI, and 18FDG-PET images. Our results suggest that ultrasonography may be a very useful tool for diagnosis of postoperative stitch abscess and may help improve the quality of life of oral SCC patients.