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Purpose Stellate ganglion block (SGB) is effective in treating head and neck pain and neuropathic diseases by increasing tissue blood flow through its sympatholytic effect. This study aimed to investigate the relationship between duration of cervical sympathetic nerve block by SGB and its therapeutic efficacy against trigeminal neuropathy after orthognathic surgery. Methods Twenty-eight patients with trigeminal neuropathy were randomly assigned to two groups (mepivacaine and levobupivacaine) according to the drug used for SGB. Increased blood flow, which is a symptom of sympathetic blockade, was recorded for 180 min after SGB. Current perception threshold, warm or cool detection threshold, and tactile detection threshold were measured preoperatively, postoperatively, on day 10 after initiation of SGB, and 3 months postoperatively to compare therapeutic efficacy between the groups. Results The levobupivacaine group had a significantly longer duration of increased blood flow compared with the mepivacaine group. Values of current perception threshold, warm and cool detection threshold, and tactile detection threshold significantly improved in the levobupivacaine group on day 10 after initiation of SGB and 3 months postoperatively. Conclusion A prolonged increase in blood flow due to long-term sympatholytic effects accelerates the therapeutic efficacy of SGB in trigeminal neuropathy.

Upper airway obstruction (UAO) and oxygen desaturation are risk factors for major complications of intravenous sedation (IVS) in pediatric dental patients. This study aimed to investigate the use of a nasal high-flow (NHF) system for the prevention of UAO and oxygen desaturation in pediatric dental patients under IVS.The authors implemented a prospective randomized design. Thirty pediatric patients (aged 3 to 12), scheduled for dental treatment under IVS, were enrolled in this study. The subjects were randomly assigned to 1 of 2 groups: patients who received oxygen at 5 L/minute through a nasal cannula (NC group) and patients who received oxygen at 2 kg/L/minute, up to a maximum of 30 L/minute, through the NHF system (NHF group). The predictor variable was flow rate. The primary outcome variable was the need for intervention during treatment, and the secondary outcome variable was the lowest peripheral capillary oxygen saturation values during the procedure. Additional study variables measured included patient age, gender, weight, height, and surgical duration. The Mann-Whitney U test and Fisher exact test were used for statistical analysis, with P .05 considered as significant.Both the NC (n = 15; mean age, 6.2 ± 2.3) and NHF (n = 15; mean age, 5.9 ± 2.5) groups had a male:female ratio of 2:1. The use of the NHF system significantly improved the lowest peripheral capillary oxygen saturation values during treatment (P .05). Jaw lifting, to relieve UAO and facilitate spontaneous breathing, was required in both the NC (n = 10) and NHF (n = 3) groups (P .05). The need for interventions during treatment was significantly lower in the NHF group (P .05).The results of this study suggest that the use of the NHF system can prevent UAO and improve the respiratory condition of pediatric dental patients under IVS.

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a rare form of primary headache, classified as trigeminal autonomic cephalalgia. Since the underlying mechanism of the pathogenesis has not yet been determined, a standardized therapeutic strategy for SUNCT is unavailable. We present a case of SUNCT syndrome with successful pain relief by intravenous administration of ketamine, an N-methyl-D-aspartate receptor (NMDAR) antagonist.A 56-year-old male patient reported severe throbbing and shooting pain in forehead, temporal and periorbital region. We confirmed conjunctival injection, lacrimation, blepharoptosis, and miosis as symptoms related to autonomic activity, and made a diagnosis of SUNCT based on ICHD-3 beta. Numerous treatments were attempted, including pregabalin, gabapentine, nonsteroidal antiinflammatory drugs, acetaminophen, steroids, antidepressants, triptans, nerve blocks, and intravenous lidocaine with unsatisfactory results. Intravenous administration of ketamine (0.4 mg/kg) for one hour, was found to relieve the severe pain.Intravenous ketamine can effectively treat SUNCT syndrome. This case demonstrated that involvement of NMDAR could be one of the mechanisms of SUNCT syndrome pathogenesis and establish a therapeutic strategy for this pain syndrome.

Background N-acetyl-p-aminophenol (APAP, acetaminophen, paracetamol) is a widely used analgesic/antipyretic with weak inhibitory effects on cyclooxygenase (COX) compared to non-steroidal anti-inflammatory drugs (NSAIDs). The mechanism of action of APAP is mediated by its metabolite that activates transient receptor potential channels, including transient receptor potential vanilloid 1 (TRPV1) and TRP ankyrin 1 (TRPA1) or the cannabinoid receptor type 1 (CB1). However, the exact molecular mechanism and target underlying the cellular actions of APAP remain unclear. Therefore, we investigated the effect of APAP on osteoblastic differentiation and cell migration, with a particular focus on TRP channels and CB1. Methods Effects of APAP on osteoblastic differentiation and cell migration of MC3T3-E1, a mouse pre-osteoblast cell line, were assessed by the increase in alkaline phosphatase (ALP) activity, and both wound-healing and transwell-migration assays, respectively. Results APAP dose-dependently inhibited osteoblastic differentiation, which was well correlated with the effects on COX activity compared with other NSAIDs. In contrast, cell migration was promoted by APAP, and this effect was not correlated with COX inhibition. None of the agonists or antagonists of TRP channels and the CB receptor affected the APAP-induced cell migration, while the effect of APAP on cell migration was abolished by down-regulating TRPV4 gene expression. Conclusion APAP inhibited osteoblastic differentiation via COX inactivation while it promoted cell migration independently of previously known targets such as COX, TRPV1, TRPA1 channels, and CB receptors, but through the mechanism involving TRPV4. APAP may have still unidentified molecular targets that modify cellular functions.

Intravenous sedation (IVS) is commonly used to complete dental treatment for uncooperative pediatric patients. Propofol (PRO) is widely used for IVS because of its short context sensitive half-time and amnestic effect. However, administering PRO to patients who have a history of egg anaphylaxis is still somewhat controversial. The evidence that supports the potential risks for allergic reactions following PRO use in patients with egg allergies is limited with some anesthesiologists recommending against its use in these patients. Alternative drug regimens for procedural sedation in this population are therefore desirable. Dexmedetomidine (DEX), a selective α-2 agonist, has antianxiety and sedative properties and has been widely used not only for procedural sedation with mild inhibitory effects on respiration but also during minor surgeries for its analgesic effect. In this paper, we describe the successful administration of a combination of DEX and low-dose midazolam (MDZ) for sedation in an uncooperative pediatric patient. Both DEX and MDZ have been reported as safe and useful sedatives for dental treatment, and their combination may provide a helpful option for IVS of pediatric patients for whom PRO is not preferred.

The aim of this study was to determine whether the evaluation of neurovascular compression (NVC) using new criteria on magnetic resonance (MR) cisternography improves the prediction of the curative effects of carbamazepine (CBZ) in trigeminal neuralgia (TN). In this study, a new analysis of NVC using MR cisternography was performed retrospectively for 280 patients with clinical signs and symptoms suggesting TN. The new analysis examined whether the site of the NVC was less than 3mm from the edge of the exit point and within the first third of the root entry zone on MR cisternography. Prediction of the curative effects of CBZ using the new evaluation of distance to the NVC improved on the predictive ability of the previous method of calculating the NVC volume (Mantel-Haenszel coefficient, P 5mm3. The evaluation of NVC on MR cisternography using this new approach appears to be more useful than the previous method for predicting the initial treatment response in patients with TN.

Purpose Hypoxia is a major complication in dental patients under intravenous sedation (IVS). A nasal high-flow (NHF) system has been reported to achieve effective oxygenation in patients with sleep apnea syndrome. This study investigated the ability of the NHF system to prevent hypoxia in dental patients under IVS. Materials and Methods Thirty patients scheduled for dental treatment under IVS were enrolled. Patients were randomly divided into 3 groups: patients spontaneously breathing oxygen at 5 L/minute through a nasal cannula (NC5 group), patients administered oxygen at 30 L/minute through the NHF system, and patients administered oxygen at 50 L/minute through the NHF system. Hypnosis was induced by bolus administration of midazolam (0.05 mg/kg) followed by continuous administration of propofol (target blood concentration, 1.2 to 2 μg/mL). Noninvasive blood pressure, peripheral capillary oxygen saturation (SpO2), heart rate, and bispectral index values were recorded every 2.5 minutes before the induction of anesthesia. Interventions, such as jaw lifting, were recorded during IVS and arterial blood gas analysis was performed at the end of sedation. Patient and surgeon satisfaction with IVS was evaluated by interview. Results Minimum SpO2 was lowest in and surgeons were least satisfied with the NC5 group. In addition, interventions were required most frequently in the NC5 group (P < .05). Compared with the NC5 group, use of the NHF system improved partial pressures of oxygen and carbon dioxide in dental patients under IVS (P < .05). Conclusions These results suggest that use of the NHF system can prevent hypoxia in dental patients under IVS. Further studies are necessary to determine the appropriate flow rate and indications for NHF in obese patients.

Subjects The purpose of this study was to evaluate the treatment modalities for neurosensory disturbances (NSDs) of the inferior alveolar nerve occurring after retromolar bone harvesting for bone augmentation procedures before implant placement. Methods One hundred four patients, of which 49 and 55 exhibited vertical or horizontal alveolar ridge defects in the mandible and maxilla, respectively, were enrolled. Nineteen patients underwent block bone grafting, 38 underwent guided bone generation or autogenous bone grafting combined with titanium mesh reconstruction, and 47 underwent sinus floor augmentation. Using a visual analog scale, we examined subjective symptoms and discomfort related to sensory alteration within the area of the NSDs in these patients. NSDs were clinically investigated using a two-point discrimination test with blunt-tipped calipers. In addition, neurometry was used for evaluation of trigeminal nerve injury. We tested three treatment modalities for NSDs: follow-up observation (no treatment), medication, and stellate ganglion block (SGB). Results A week after surgery, 26 patients (25.0%) experienced NSDs. Five patients received no treatment, 10 patients received medication, and 11 patients received SGB. Three months after surgery, patients in the medication and SGB group achieved complete recovery. Current perception threshold values recovered to near-baseline values at 3 months: recovery was much earlier in this group than in the other two groups. SGB can accelerate recovery from NSDs. Conclusions Our results justify SGB as a reasonable treatment modality for NSDs occurring after the harvesting of retromolar bone grafts.

Recent evidence implicates endothelin in nociception, but it is unclear how endothelin activates trigeminal ganglion (TRG) neurons. In the present study, we investigated the expression of the endothelin receptors ETA and ETB and endothelin-induced responses in rat TRG neurons. Double-immunofluorescence studies demonstrated that ETA and ETB were expressed in TRG neurons and that 26% of ETA- or ETB-expressing neurons expressed both receptors. During whole-cell patch-clamp recording, endothelin-1 enhanced an induced current in response to capsaicin, a TRPV1 agonist, in approximately 20% of dissociated neurons. The enhancement was blocked by the PKC inhibitor chelerythrine and by the ETA antagonist BQ-123, but not by the ETB antagonist BQ-788. Ca2+-imaging showed that endothelin-1 increased the intracellular Ca2+ concentration in more than 20% of the dissociated neurons. Importantly, unlike the effect of endothelin-1 on capsaicin-induced current, the Ca2+ response was largely suppressed by BQ-788 but not by BQ-123. These results suggest that ETA-mediated TRPV1 hyperactivation via PKC activation and ETB-mediated Ca2+ mobilization occurs in different subsets of TRG neurons. These endothelin-induced responses may contribute to the induction of orofacial pain. The ETB-mediated function in TRG neurons is a special feature in the trigeminal system because of no ETB expression in dorsal root ganglion neurons.

This review article provides doctors and dentists with an introduction to the clinical applications and sig- nificance of magnetic resonance cisternography (MRC) for the evaluation of neurovascular compression of the trigeminal nerve in patients with trigeminal neu- ralgia (TN). Specifically, the method and characteris- tics of MRC are first explained using the relevant MR sequences. Next, clinical applications for the diagnosis of TN are discussed. Finally, the significance and util- ity of MRC for effective treatment of patients with TN, such as carbamazepine administration and/or local anesthetic blocks, are presented.

Purpose We examined the effects of sweet taste stimulation on pain tolerance threshold (PTT) of oral mucosa in children. Subjects and methods Subjects comprised 10 children (mean age, 7.3±1.2 years) for whom PTT of oral mucosa was measured 2min after oral administrations of sucrose or xylitol and water. Sine wave current stimulation (2kHz, 250Hz and 5Hz, SWCS) which can stimulate sensory nerve fiber selectively (A β , A δ and C) was used to measure PTT. Results Sweet taste stimulation with sucrose or xylitol increased oral mucosa PTT in children, but not in adults. No difference in the increased PTT was seen between sucrose and xylitol. Conclusions Oral administration of sucrose and xylitol may potentially relieve pain associated with local anesthetic injections in children.

Objectives The aim of this study was to evaluate the 3-dimensional images of thinner main peripheral vessels in oral and maxillofacial regions made without contrast medium by using a new technique, fresh blood imaging (FBI). A second objective was to discern arteries from veins by using the combination of FBI with the subtraction technique. Study design Images from FBI were compared with those from 3-dimensional phase-contrast magnetic resonance angiography (MRA) of blood vessels in 20 healthy subjects. All images were scored for visualization and image quality of the main blood vessels. In addition, appropriate flow-spoiled gradient pulses were applied to differentiate arteries from veins in the peripheral vasculature using a combination of FBI sequences and subtraction between systole- and diastole-triggered images. Results The scores of MRA using FBI for the visualization of thin blood vessels were significantly better than those using phase contrast, whereas scores for the visualization of main blood vessels were equal. Additionally, we succeeded in our initial attempt to differentiate arteries from veins with a reasonable acquisition time. Conclusions Our initial experience shows that FBI could be a useful method to identify 3-dimensional vasculature and to differentiate arteries from veins among thinner peripheral vessels in the oral and maxillofacial regions without using contrast medium.

Background Dentists need to be aware of the relationship between malignancies and paresthesia or complete loss of sensation in a jaw segment. In particular, dentists should be aware of numb chin syndrome (NCS) and its clinical manifestations, as well as the limitations of using panoramic radiographs to detect the causative malignancy. Case Descriptions The authors report two cases of paresthesia in the mental region. No lesions were readily apparent on the patients' panoramic radiographs. To exclude the presence of disease in the mandible that could have been responsible for the NCS, the authors obtained computed tomographic (CT) images. They identified metastases to the mandible from primary malignant tumors elsewhere in the body. Clinical Implications To prevent misdiagnosis of NCS, dentists need to be aware of the clinical manifestations of NCS, the need for CT imaging, the shortcomings of panoramic radiographs and the value of obtaining detailed and accurate medical and dental histories from patients.

Takayasu arteritis is a rare chronic progressive panendarteritis involving the aorta and its main branches. Anesthesia in patients with this disease can be complicated by severe uncontrolled hypertension, end-organ dysfunction, and stenosis of major blood vessels. In this case, general anesthesia was induced with sevoflurane and remifentanil without complications. To prevent intraoperative complications, we conducted intubation with a rigid video laryngoscope with careful consideration of the concentrations of analgesics and sedatives used. This case demonstrates the importance of anesthetic techniques for maintaining adequate tissue perfusion without hemodynamic changes in the anesthetic management of patients with Takayasu arteritis.

顎関節症における疼痛と関連する病態について概説した．顎関節症の痛みは，咀嚼筋および顎関節から生じ，その病態の発生には，安静時の無意識な上下歯牙の接触による閉口筋の筋緊張が存在していることが多い．この疼痛を寛解させるには，筋のリラックスとストレッチを中心とした行動療法とトリガーポイント注射，物理療法等の併用が推奨されており，三環系抗うつ薬を除く多くの薬物療法ならびにスプリント療法はそのエビデンスが証明されていない．疼痛性疾患は種々分類されるが，顎関節症として扱われる咀嚼筋，顎関節由来の疼痛は深部体性痛に属し，他の顔面の深部組織に由来する疼痛と性質は大きく変わらない．顎関節症と鑑別を要する病態としては，深部体性痛を呈する他の疾患や神経因性疼痛，精神疾患に伴う疼痛がある．深部体性痛を呈する疾患には，咀嚼筋以外の筋痛，一次性頭痛，鼻・上顎洞疾患，骨疾患（骨髄炎），頚椎疾患，頭頸部の自己免疫疾患などがあり，これらの病態には，末梢からの侵害刺激による中枢神経の感作，可塑化が深く関係している．深部体性痛では，二次ニューロンの感作，可塑化に伴って，受容野を共有する部位に関連痛を生じることになり，この関連痛が顎関節症の疼痛を複雑にする．神経因性疼痛としては，発作性神経痛，精神疾患としては，身体表現性障害やうつなどがあげられる．疼痛が発生している組織の病態の理解が重要である．

Headache associated with cervical lesions is called cervicogenic headache and involves the occiput but not the orofacial region. However, patients occasionally present with orofacial pain accompanied by neck symptoms. This study investigates whether orofacial pain can originate from the neck and whether cervical plexus block can help in diagnosis. We enrolled eight patients suffering from chronic orofacial pain that had not been relieved by dental treatment. Radiographic and magnetic resonance imaging revealed abnormal findings in the neck in seven of them. To identify the origin of the orofacial pain, we firstly blocked peripheral sensory input from the oral cavity and surrounding tissues, followed by that from deep cervical structures. We injected local anesthetics around the painful orofacial region, then to the tender points in the masticatory and superficial cervical muscles (trigger point injection), and consequently around the cervical plexus. Pain was assessed using a pain relief score compared with pre-treatment control values. Local anesthesia in the painful oral region provided insufficient relief whereas trigger point injection significantly relieved pain. The amount of pain relief generated by the deep cervical plexus block was more significant than that produced by any other procedures. We conclude that certain types of orofacial pain originate from cervical structures and that a deep cervical plexus block can be helpful in differentially diagnosing such pain.

Objective To evaluate the utility of magnetic resonance (MR) cisternography using 3-dimensional (3D) fast asymmetric spin-echo (FASE) sequences with multiplanar reconstruction (MPR) for detection of the sites of neurovascular compression (NVC) in patients with trigeminal neuralgia. Study design Both MR cisternography with 3D-FASE sequences and MR angiography (MRA) were performed on 150 patients with clinical signs and symptoms that suggested trigeminal neuralgia. Results from the original MR cisternography with 3D-FASE sequences, the original MRA, and 4 reformatted images were used for interpretation. Images with inversion between black and white were used from the MR cisternography with 3D-FASE sequences to evaluate NVC. A diagnosis of NVC was made from the presence of vascular contact with the trigeminal nerve at the root entry zone (REZ) and the nature of the involved vessels. For the patients with NVC detectable on 3D-FASE or MRA images, the relationship between the clinically manifested regions and the NVC sites was also evaluated. Results Of the 150 patients evaluated, 89 were deemed to have NVC. Of these 89 patients, 3 underwent surgery that identified the artery that was involved with the trigeminal nerve. The correlation between the clinically manifested regions and the NVC sites was significantly detectable using both 3D-FASE images and MRA in 89 patients with detectable NVC. The correlation coefficient using 3D-FASE imaging was a little higher than that using MRA. Of the 61 patients deemed not to have NVC, 6 were found to have brain tumors that invaded the root entry zone of the trigeminal nerve. However, the remaining 55 patients had no identifiable cause for trigeminal neuralgia. NVC was found in the asymptomatic side in 27 (18%) of the 150 patients with trigeminal neuralgia using MR cisternography with 3D-FASE sequences. Conclusions The technique of MR cisternography using 3D-FASE sequences with MPR is more accurate and useful than MRA for detection of the site of NVC in patients with trigeminal neuralgia. Patients with trigeminal neuralgia should be further examined using MR imaging to rule out a brain tumor. Radiologists should understand that a few subjects with no symptoms could show NVC with MR cisternography.

Venipuncture is often accompanied by pain, which can compromise dental care and foment distrust toward dental care providers. The aim of the present study was to identify sites on the forearm and hand that have the greatest pain tolerance threshold (PTT) during venipuncture.The PTT was estimated in 20 healthy volunteers using a noninvasive nerve conduction threshold device. The subjects self-stimulated 5 sites (median cubital vein, cephalic vein at the cubitus, basilic vein, cephalic vein at the carpus, and superficial dorsal vein) at 2 kHz, 250 Hz, and 5 Hz. We measured the stimulation intensity before the subject deactivated the device. Differences in the average PTT values at each site were compared using the Kruskal-Wallis and Scheffé tests. P.05 was considered to indicate statistical significance.The PTT was significantly greater at the superficial dorsal vein than at the basilic vein for all 3 noninvasive nerve conduction threshold frequencies (P.05). The estimated PTT was significantly greater at the superficial dorsal vein than at the median cubital vein and cephalic vein at the carpus in response to 250-Hz stimulation (P.05).The greater PTT of the superficial dorsal vein suggests that venipuncture at this site should result in the lowest pain intensity among all upper limb sites.

Background The purpose of this study was to use functional magnetic resonance imaging (fMRI) to quantify changes in brain activity during experimental occlusal interference. Methods Fourteen healthy volunteers performed a rhythmical tapping occlusion task with experimental occlusal interference of the right molar tooth at 0 mm (no occlusion), 0.5 mm, and 0.75 mm. The blood-oxygen-level dependent (BOLD) signal was quantified using statistical parametric mapping and compared between rest periods and task periods. Results In tapping tasks with experimental occlusal interference of 0.75 mm or 0.5 mm, there was clear activation of the contralateral teeth-related primary sensory cortex and Brodmann’s area 46. At 0 and 30 minutes after removal of the experimental occlusal interference, the activation clearly appeared in the bilateral teeth-related primary sensory cortices and Brodmann’s area 46. At 60 minutes after the removal of the experimental occlusal interference, the activation of Brodmann’s area 46 had disappeared, and only the bilateral teeth-related primary sensory cortices were active. Conclusions The present results suggest that adjustments for experimental occlusal interference can be objectively evaluated using fMRI. We expect that this method of evaluating adjustments in occlusal interference, combined with fMRI and the tapping task, could be applied clinically in the future.

The purpose of this study was to compare pre- and postoperative autonomic activities and changes in salivary stress biomarkers between patients who received only local anesthesia and those who received local anesthesia together with intravenous sedation in dental implant surgery.A total of 21 patients were enrolled in this non-randomized controlled prospective study; 7 subjects underwent implant surgery under local anesthesia with intravenous sedation and 14 subjects underwent surgery under only local anesthesia. Stress was evaluated by measuring salivary levels of chromogranin A (CgA) and a spectral analysis of heart rate variability (HRV) at baseline (on a day other than the day of surgery), 1h preoperatively, and 1h postoperatively. HRV analysis yields low- (LF) and high-frequency (HF) components, the LF/HF ratio, and the component coefficient of variance (CCV[HF]), which provide indices of sympathetic and parasympathetic regulatory activity.CgA levels were significantly higher (p0.05) at baseline in patients who received sedation than those who did not, but CgA levels did not differ prior to surgery. Also, the values of most parameters, including LF, HF, LF/HF (L/H), and CCV(HF), did not significantly differ between groups or among the three time points. Only ΔL/H and ΔCCV(HF) were significantly lower (p0.05) at 1h preoperatively in patients who received sedation than those who received only local anesthesia.CgA levels were high in both groups immediately before surgery, and thus CgA values immediately before surgery may not be a reliable indicator of the need for intravenous sedation. Also, spectral analysis of HRV, especially ΔL/H and ΔCCV(HF), could be useful for assessing tension and anxiety.

Although recent evidence suggests that central glial hyperactivation is involved in cancer-induced persistent pain, the time course of this hyperactivation and the glial contribution to pain hypersensitivity remain unclear. The present study investigated the time-dependent spatial changes of microglial and astrocytic hyperactivation in the trigeminocervical complex, which consists of the medullary (MDH) and upper cervical (UCDH) dorsal horns, and pain-related behaviors in a rat facial cancer model in which Walker 256B-cells are inoculated into the vibrissal pad. In this model, the tumors grew within the vibrissal pad, from which sensory nerve fibers project into the MDH, but did not expand into the infraorbital region, from which fibers project into the UCDH. Nevertheless, mechanical allodynia and thermal hyperalgesia were observed not only in the vibrissal pad but also in the infraorbital region. Western blotting and immunofluorescence studies indicated that microglia were widely activated in the trigeminocervical complex on day 4 and gradually inactivated by day 11. In contrast, astrocytes were only activated in the MDH on day 4; the hyperactivation later expanded into the UCDH. Daily administration of the glial hyperactivation inhibitor propentofylline beginning on day 4 suppressed the glial hyperactivation on later days. Propentofylline treatment largely prevented allodynia/hyperalgesia in the infraorbital region beginning on day 5, although established allodynia/hyperalgesia in the vibrissal pad was less sensitive to the treatment. These results suggest that central glial hyperactivation, transient microglial hyperactivation and persistent astrocytic hyperactivation, contributes to the development of pain hypersensitivity but not to the maintenance of pain in this model.

Objectives Whether NVC volume on magnetic resonance (MR) cisternography might be related to the success of local anesthetic block by tetracaine (TNB) as an additional treatment after carbamazepine (CBZ) treatments in patients with trigeminal neuralgia (TN) was evaluated. Study Design Detectable NVC volumes were measured from MR cisternography in 65 patients with TN treated by TNB after CBZ treatments. The correlation between the success of TNB and the NVC volume or the improvement in pain by CBZ was evaluated retrospectively. Results A significant difference was found between the improvement in pain by CBZ and the success of TNB, but not between NVC volume on MR cisternography and the success of TNB. Conclusions The present results suggest that the success of CBZ as initial treatment, but not NVC volume on MR cisternography, may be a significant predictor of the success of TNB as additional therapy in patients with TN.

Computed tomography (CT) scanning is very useful in identifying and evaluating the location, size, and suspected pathological diagnosis of lesions such as cysts, tumors, and infections. At the same time, it aids in the elucidation of bone and surrounding soft tissue invasion of lesions with high resolution.1, 2 In the maxilla and mandible, teeth are included and the CT capacity there can distinguished a foreign body of only 30 μm. Precise size and location are needed in the evaluation of lesions in the maxilla and mandible based on a high resolution in addition to the suspected pathological diagnosis based on CT findings. Therefore, multi-detector CT (MDCT) scanning is commonly applied for various kinds of lesions in the maxilla and mandible because of its precision and diagnostic accuracy. Multidetector CT scanning provides rapid acquisition of numerous thin axial images and more accurate reconstruction images. Multi-detector CT scanning provides accurate information about the height, width, and three-dimensional (3D) evaluation of the maxilla and mandible, as well as detailed information about the location of normal anatomical structures, such as the mandibular canal, mental foramen, mandibular foramen, incisive foramen, and maxillary sinus. In addition, the relationship between lesions and anatomical landmarks, including cortical margins and roots of teeth, can be established. These images are also excellent because MDCT eliminates streak artifacts from dental restorations that degrade direct coronal CT scans. With MDCT, axial images are used to reformat the cross-sectional images, projecting the artifact along the crowns of the teeth rather than over the bone that is the region of interest.3 At the same time, CT readings of lesions in the maxilla and mandible measured by MDCT can reflect the nature and inclusion within lesions, from which

In the present case of a 9-year-old girl with prominent swelling in the mental and facial regions after trauma, repeated magnetic resonance (MR) examinations were performed to evaluate areas of incision, because the swelling became worse and more prominent despite intravenous antibiotic treatment. However, there was no evidence of respiratory tract impingement or deformation, including obliteration, on MR imaging. Therefore, surgical treatment involving an incision because of facial region swelling was cancelled, and the intravenous antibiotic therapy was continued. To prevent misdiagnosis and over-treatment of young children with inflammation of the oral and maxillofacial regions, dentists, including pediatric dentists, should be aware of the clinical usefulness of MR examinations. In particular, MR examinations are non-invasive for young children, because there is no X-ray exposure, and they can be used repetitively. At the same time, the present case demonstrated that it is very difficult to understand and predict changes in the inflammation process associated with children's facial trauma.

Peripheral and central glial activation plays an important role in development of pain hypersensitivity induced by inflammation and nerve injury. However, the involvement of glial cells in cancer pain is not well understood. The present study evaluated the peripheral and central glial activation and the effect of an inhibitor of glial activation, propentofylline, on pain-related behaviors in a rat facial cancer model of the growth of Walker 256B cells in the unilateral vibrissal pad until days 3-4 post-inoculation. As compared with sham animals, the facial grooming period was prolonged, the withdrawal latency to radiant heat stimulation was shortened, and the withdrawal threshold by von Frey hair stimulation was decreased at the inoculated region, indicating the development of spontaneous pain, thermal hyperalgesia and mechanical allodynia. In immunostainings for Iba1 and glial fibrillary acidic protein (GFAP), although there were no morphological changes of GFAP-immunopositive satellite glial cells in the trigeminal ganglion, Iba1-immunopositive microglia and GFAP-immunopositive astrocytes in the medullary dorsal horn showed large somata with cell proliferation. After the daily i.p. administration of propentofylline beginning pre-inoculation, the central glial activation was attenuated, the prolonged facial grooming was partially suppressed, and the induced allodynia and hyperalgesia from day 2 were prevented, without a change in tumor size. These results suggest that glial activation in the CNS, but not in the peripheral nervous system, mediates the enhancement of spontaneous pain and the development of allodynia and hyperalgesia at an early stage in the facial cancer model.

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.

Objective. To present a case of complex regional pain syndrome (CRPS) type II with sympathetic dys- function and trophic changes in the orofacial region, which was partially responsive to intravenous ketamine. Patient. The patient was a 68-year-old man who suf- fered from inveterate pain with trophic changes of the right face and tongue and vasomotor dysfunc- tion on the right side of the face after ipsilateral trigeminal nerve block. Allodynia and hyperalgesia were observed on the affected side of the face. Pain initially improved after sympathetic nerve block, but similar pain returned that was unresponsive to the same procedure. Repeated intravenous administra- tion of low-dose ketamine preceded by intravenous midazolam alleviated the pain, but trophic changes of the tongue persisted. Discussion. CRPS in the orofacial region has not been clearly defined and has been infrequently documented. Clinical findings in this patient met the criteria of the International Association for the Study of Pain's and Harden's diagnostic criteria for CRPS. The reason for gradual pain relief after induction of intravenous ketamine therapy was unclear, but the fact that only ketamine and not other various pain medicines or procedures alleviated the pain is important to note. Conclusion. Distinct cases of CRPS involving the orofacial region are rare. Thorough observations and documentation of signs and symptoms may lead to future standardization of diagnostic criteria and treatment strategies for this disorder.

OBJECTIVES: To 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. METHODS: MR 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. RESULTS: Of 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. CONCLUSIONS: Three-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.

Dentists need to be aware of the relationship between malignancies and paresthesia or complete loss of sensation in a jaw segment. In particular, dentists should be aware of numb chin syndrome (NCS) and its clinical manifestations, as well as the limitations of using panoramic radiographs to detect the causative malignancy.The authors report two cases of paresthesia in the mental region. No lesions were readily apparent on the patients' panoramic radiographs. To exclude the presence of disease in the mandible that could have been responsible for the NCS, the authors obtained computed tomographic (CT) images. They identified metastases to the mandible from primary malignant tumors elsewhere in the body.To prevent misdiagnosis of NCS, dentists need to be aware of the clinical manifestations of NCS, the need for CT imaging, the shortcomings of panoramic radiographs and the value of obtaining detailed and accurate medical and dental histories from patients.