Ganglion cyst in the temporomandibular joint: A case report and discussion of surgical approaches.

Background: Ganglion cysts in the temporomandibular joint are treated by resection; however, there has been insufficient discussion regarding the appropriate approach for surgical resection. Clinical presentation: A 55-year-old man presented with a left preauricular swelling for one year. The examination revealed a moderately hard mass with a 30-mm diameter, tenderness, and restricted movement. Magnetic resonance imaging showed a cystic lesion with a 25 mm-long axis. Considering a diagnosis of temporomandibular cyst, separation of the cyst wall through a preauricular incision was attempted. However, the cyst ruptured due to strong adherence on the reverse side. Curettage followed by discectomy was performed. Histopathological diagnosis was of a ganglion cyst. Among 39 reported cases, 24 were excised via the preauricular approach, with 8 intraoperative cyst ruptures. Conclusion: The parotidectomy approach should be employed when the cyst is large, at a low position, or adherent to the surrounding tissue, in order to achieve reliable excision.

Expression of Sphingosine Kinase-1 Is Associated with Invasiveness and Poor Prognosis of Oral Squamous Cell Carcinoma.

BACKGROUND/AIM: The expression of sphingosine kinase-1 (SphK1) has been reported in several cancers. However, the exact roles of SphK1 in cancer progression still remain unknown. The aim of the present study was to investigate SphK1 expression in oral squamous cell carcinoma (OSCC) and clarify the involvement of SphK1 in the proliferation and invasiveness of OSCC and its prognostic implications. MATERIALS AND METHODS: Expression of SphK1, E-cadherin, vimentin, and Ki-67 were examined in 69 OSCC tissues immunohistochemically, as well as by western blot, and correlations between their expression and relationships with tumor invasiveness and prognosis were analyzed. RESULTS: SphK1 was expressed in the tumor cells of 38 of 69 OSCCs, particularly at the invasion front. Patients with OSCCs with high SphK1 expression showed higher invasive grades and unfavorable survival rates. SphK1 expression correlated with acquisition of vimentin expression and loss of E-cadherin expression; there was no significant difference in Ki-67 labeling indices between OSCCs with high and low SphK1 expression. CONCLUSION: These results demonstrate the involvement of SphK1 in the invasiveness of OSCC and in unfavorable prognosis, indicating its role in the epithelial-mesenchymal transition of OSCC cells.

Anti-inflammatory Activity of Hangeshashinto in IL-1ß-stimulated Gingival and Periodontal Ligament Fibroblasts.

Although a large number of Kampo, Japanese traditional medicines, have been used for the treatment of oral diseases, little is known on their relative potency and endotoxin contamination. In order to obtain basic data for clinical applications, 10 Kampo, and 25 constituent plant extracts were tested for the contamination of lipopolysaccharide (LPS)-like substances, and anti-inflammatory activity. Human gingival (HGF) and periodontal ligament fibroblasts (HPLF) were cultured in 10% fetal bovine serum supplemented with Dulbecco's modified Eagle's medium. Viable cell number was measured by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Prostaglandin (PGE2) was determined by enzyme immunoassay. Cyclo-oxygenase (COX)-1 and COX-2 protein expressions were determined by western blot. COX activity was measured using Cox Inhibitor Screening Assay Kit. LPS, quantified by Endotoxin assay kit, was undetectable or relatively low in the test samples except for rikkosan and unseiin. Hangeshashinto potently inhibited PGE2 production by interleukin (IL)-1ß-stimulated HPLFs and HGFs. Hangeshashinto suppressed the expression of COX-2 protein, but not that of COX-1 protein in IL-1ß-induced HGF cells. Hangeshashinto slightly, but not significantly, inhibited both COX-1 and COX-2 activity. The present study provides the basis for clinical application of hangeshashinto for the treatment of stomatitis.

Polyhedral microcrystals encapsulating bone morphogenetic protein 2 improve healing in the alveolar ridge.

Atelocollagen sponges incorporating polyhedra encapsulating bone morphogenetic protein 2 (BMP-2) were implanted into lateral bone defects in the mandible. Half of the bone defects on the left side were treated with atelocollagen sponges containing 1.8 × 10(7) BMP-2 polyhedra, and half were treated with sponges containing 3.6 × 10(6) BMP-2 polyhedra. As controls, we treated the right-side bone defects in each animal with an atelocollagen sponge containing 5 µg of recombinant human BMP-2 (rhBMP-2) or 1.8 × 10(7) empty polyhedral. After a healing period of six months, whole mandibles were removed for micro-computed tomography (CT) and histological analyses. Micro-CT images showed that more bone had formed at all experimental sites than at control sites. However, the density of the new bone was not significantly higher at sites with an atelocollagen sponge containing BMP-2 polyhedra than at sites with an atelocollagen sponge containing rhBMP-2 or empty polyhedra. Histological examination confirmed that the BMP-2 polyhedra almost entirely replaced the atelocollagen sponges and connected the original bone with the regenerated bone. These results show that the BMP-2 delivery system facilitates the regeneration of new bone in the mandibular alveolar bone ridge and has an advance in the technology of bone regeneration for implant site development.

Rheumatoid nodule in the lower lip of a patient with rheumatoid arthritis: a novel case report and review of literature.

PURPOSE: Rheumatoid nodules are a well-characterized common extra-articular manifestation of rheumatoid arthritis. However, the occurrence of a rheumatoid nodule in the oral mucosa is extremely rare. PATIENTS AND METHODS: We present the case of a rheumatoid nodule in the lower lip, which rarely presents with variations in the clinical manifestation, that occurred in a 48-year-old female patient with rheumatoid arthritis. The nodule was totally excised under the clinical diagnosis of either a fibroma or salivary gland lesion. RESULTS: On histopathologic examination, within the deep mucosa, a necrobiotic nodule surrounded by elongated histiocytic cells with a focal palisaded arrangement. The lesion was diagnosed postoperatively as a rheumatoid nodule from the histopathologic and clinical findings. CONCLUSIONS: Few studies have been performed of oral rheumatoid lesions; however, a review of the published data showed that this is the first case of a rheumatoid nodule in the lower lip of a patient with rheumatoid arthritis.

Enhancement of oscillatory activity in the endopiriform nucleus of rats raised under abnormal oral conditions.

Endopiriform nucleus (EPN) is located deep to the piriform cortex, and has neural connections with not only neighboring sensory areas but also subcortical areas where emotional and nociceptive information is processed. Well-balanced oral condition might play an important role in stability of brain activities. When the oral condition is impaired, several areas in the brain might be affected. In the present study, we investigated whether abnormal conditions of oral region influence neural activities in the EPN. Orthodontic appliance that generates continuous force and chronic pain-related stress was fixed to maxillary incisors of rats, and raised. Field potential recordings were made from the EPN of brain slices. We previously reported that the EPN has an ability to generate membrane potential oscillation. In the present study, we have applied the same methods to assess activities of neuron clusters in the EPN. In the case of normal rats, stable field potential oscillations were induced in the EPN by application of low-frequency electrical stimulation under the medium with caffeine. In the case of rats with the orthodontic appliance, stable field potential oscillations were also induced, but both duration of oscillatory activities and wavelet number were increased. The enhanced oscillations were depressed by blockade of NMDA receptors. Thus, impairment of oral health under application of continuous orthodontic force and chronic pain-related stress enhanced neural activities in the EPN, in which up-regulation of NMDA receptors may be concerned. These findings suggest that the EPN might be involved in information processing with regard to abnormal conditions of oral region.

Bilateral craniofacial microsomia: orthognathic treatment for an advanced dentofacial deformity.

In this article, we report the combined surgical and orthodontic treatment for a patient with bilateral craniofacial microsomia and facial asymmetry.

Influences of audio-visual environments on feelings of deliciousness during having sweet foods: an electroencephalogram frequency analysis study.

Feelings of deliciousness during having foods are mainly produced by perceptions of sensory information extracted from foods themselves, such as taste and olfaction. However, environmental factors might modify the feeling of deliciousness. In the present study, we investigated how the condition of audio-visual environments affects the feeling of deliciousness during having sweet foods. Electroencephalograms (EEGs) were recorded from the frontal region of the scalp of healthy participants under virtual scenes of tearoom and construction work, respectively. The participants were asked to rate deliciousness after the recordings. Frequency analyses were performed from the EEGs. During having the foods, occupancy rates of beta frequency band between tearoom scenes and construction work scenes were markedly different, but not in other frequency bands. During having no food, in contrast, there was no difference of occupancy rates in respective frequency bands between the two different scenes. With regard to deliciousness during having sweet foods, all participants rated high scores under the scenes of tearoom than those under the scenes of construction work. Interestingly, there is a positive correlation between occupancy rates of beta frequency band and scores of deliciousness. These findings suggest that comfortable audio-visual environments play an important role in increasing the feeling of deliciousness during having sweet foods, in which beta frequency rhythms may be concerned with producing comprehensive feelings of deliciousness.

Correlation between stimulation strength and onset time of signal traveling within the neocortical neural circuits under caffeine application.

In general, strength of input to neocortical neural circuits affects the amplitude of postsynaptic potentials (PSPs), thereby modulating the way signals are transmitted within the circuits. Caffeine is one of the pharmacological agents able to modulate synaptic activities. The present study investigated how strength of input affects signal propagation in neocortical circuits under the application of caffeine. Spatio-temporal neural activities were observed from visual cortical slices of rats using optical recording methods with voltage-sensitive dye. Electrical stimulations were applied to white matter in the primary visual cortex with bath-application of caffeine. When the strength of stimulation was 0.3mA, signals propagated from the site of stimulation in the primary visual cortex toward the secondary visual cortex along vertical and horizontal pathways. When stimulation strength was reduced from 0.3mA to 0.07mA, start of signal propagation was delayed about 25ms without affecting field PSP amplitude or the manner of signal propagation. Conversely, co-application of caffeine and d-2-amino-5-phosphonovaleric acid (d-AP5) did not induce delays in signal start. These findings suggest that conversion of neural code from amplitude code to temporal code is inducible at the level of neocortical circuits in an N-methyl-d-aspartate (NMDA) receptor activity-dependent manner.

Evaluations of dementia by EEG frequency analysis and psychological examination.

In order to evaluate the stage of dementia, we focused attention on EEG rhythms and Hasegawa-dementia-rating scale (HDS-R). Frontal EEGs were recorded from dementia patients and normal controls during music and photo-image stimulations, and frequency analysis was performed. In the controls, profiles of rhythm pattern during music stimulation seemed to be markedly different from those during photo-image stimulation. In contrast, in dementia patients, it was difficult to find those differences. Interestingly, as HDS-R decreases, the variability of rhythm patterns also decreases. These results suggest that a decrease in cognitive function might be related to a decrease in the ability to generate various cortical rhythm patterns.

Increased levels of soluble cytokine receptors in the synovial fluid of temporomandibular joint disorders in relation to joint effusion on magnetic resonance images.

PURPOSE: The purpose of this study is to clarify the significance of joint effusion (JE) on T2-weighted magnetic resonance images of the temporomandibular joint (TMJ) in comparison to various soluble cytokine receptors in the synovial fluid of patients with temporomandibular disorders (TMDs). PATIENTS AND METHODS: Magnetic resonance imaging of 55 TMJs of 55 patients with TMD was performed, and synovial fluid samples were obtained on the same day. The grade of JE was evaluated on a scale from 0 to 3, with grade 0 indicating the absence of JE and grades 1 to 3 indicating the presence of JE. Correlations were measured between JE and the concentrations of soluble tumor necrosis factor receptors I and II, interleukin (IL) 6 soluble receptor, IL-1 soluble receptor type II, and IL-1 receptor antagonist and protein in the synovial fluid samples. RESULTS: The mean concentrations of cytokine receptors in the synovial fluid were significantly higher in the 30 joints with JE than in the 25 joints without JE. There were no correlations between the JE grade and the level of any mediators. CONCLUSION: Increased levels of cytokine receptors are likely to influence the expression of JE and may play important roles in the pathogenesis of TMD. These results also suggest that JE may reflect synovial inflammation of the TMJ.

Application of caffeine reveals input frequency-dependent determination of signal-traveling routes between primary and secondary visual cortices in rats.

Upon entering the neocortex, neural signals are required to select which neocortical circuits to propagate through. The present study focused attention on use-dependent selection of signal-traveling routes. Rat brain slices including primary visual cortex (Oc1) and the medial part of the secondary visual cortex (Oc2M) were prepared. Electrical stimulation was delivered to white matter in Oc1 and spatiotemporal aspects of traveling signals were observed using optical recording methods under caffeine application. With an interstimulus interval (ISI) of 4-8s, signals traveled horizontally along deep layers from Oc1 to Oc2M, climbed within Oc2M, then returned along layer II/III from Oc2M to Oc1. Conversely, with an ISI of 40-64s, signals climbed within Oc1 and traveled horizontally along layer II/III from Oc1 to Oc2M in parallel with signals traveling along deep layers. Pharmacological experiments with antagonists for ionotropic glutamate receptors revealed that signal-traveling routes under higher-frequency stimulation were N-methyl-d-aspartate (NMDA) receptor activity-dependent, while those at the lower-frequency were non-NMDA receptor activity-dependent. These results suggest that neural circuits between Oc1 and Oc2M possess an input frequency-dependent gating system, in which signal-traveling routes might be affected by the relative balance of receptor activities between NMDA and non-NMDA receptors.

Congenital deformities and developmental abnormalities of the mandibular condyle in the temporomandibular joint.

The temporomandibular joint (TMJ) consists of the mandibular condyle and the articular eminence of the temporal bone. The morphological development of the TMJ during prenatal life lags behind other joints in terms of both the timing of its appearance and its progress. At birth, the joint is still largely underdeveloped. There are many causes of the various growth disturbances and abnormalities of the mandibular condyle and related structures. Growth disturbances in the development of the mandibular condyle may occur in utero late in the first trimester and may result in disorders such as aplasia or hypoplasia of the mandibular condyle. Meanwhile, hyperplasia of the mandibular condyle is not visible at birth and seems to be gradually acquired during growth. In the present review article, the congenital abnormalities of the mandibular condyle are classified morphologically into three major groups and two subgroups from a clinical standpoint: (1) hypoplasia or aplasia of the mandibular condyle, including (i) primary condylar aplasia and hypoplasia, (ii) secondary condylar hypoplasia; (2) hyperplasia; and (3) bifidity. In addition, the molecular-based etiology of anomalies of the mandibular condyle is also discussed.

Multiple tooth-losses during development suppress age-dependent emergence of oscillatory neural activities in the oral somatosensory cortex.

Tooth and tooth-related organs play important roles in not only mastication, but also sensory perception in the oral region. In general, sensory neural inputs during the developmental period are required for the maturation of functions in the sensory cortex. However, whether maturations of oral somatosensory cortex (OSC) require certain levels of sensory input from oral regions has been unclear. The present study investigated the influence of multiple tooth-losses during the developmental period on age-dependent emergence of rhythmic activities of population neurons in the OSC. Low-frequency electrical stimulation was delivered to layer IV and field potentials were recorded from layer II/III in the OSC of rat brain slices. In control rats, N-methyl-d-aspartate (NMDA) receptor-dependent oscillation at 8-10 Hz appeared during postnatal weeks 2-3. In rats with extraction of multiple teeth at 17-18 days old, oscillation did not appear even at maturity, whereas in rats with multiple teeth extracted at 37-38 days old, oscillation appearances were maintained in maturity. Thus, emergence of oscillation in the OSC was suppressed by multiple tooth-losses during postnatal 2-3 weeks. These results suggest that sufficient neural inputs from the teeth and tooth-related organs during developmental periods are essential for maturation of neural functions in the OSC.

Bacterial diversity in synovial fluids of patients with TMD determined by cloning and sequencing analysis of the 16S ribosomal RNA gene.

OBJECTIVE: The purpose of this study was to examine the presence of bacteria in synovial fluids from patients with temporomandibular joint disorder (TMD) by polymerase chain reaction (PCR) targeting the 16S ribosomal RNA (rRNA) gene, followed by cloning and sequencing. STUDY DESIGN: Universal bacterial primers were used to amplify 16S rRNA genes in 28 synovial fluid samples from 27 patients with TMD (TMD group) as well as control subjects: 5 patients with dislocation of TMJ (non-TMD group). Subsequently, PCR amplicons were purified and cloned. Partial 16S rRNA sequences of the cloned insert were used to determine the species identities or closest relative by comparison with known sequences using GeneBank. RESULTS: Nineteen (67.86%) of 28 samples from patients in the TMD group were identified with the presence of bacterial DNA by PCR. The 5 control samples from the nonTMD group were all negative in this study. After cloning and sequencing, a total of 11 bacterial species was detected, including Granulicatella adiacen (6 samples), Pseudomonas sp. (6 samples), Methylobacterium sp. (5 samples), and Beta proteobacterium (4 samples). Other species, such as Acidovorax sp., Bradyrhizobium sp., Sphingomonas, Streptococcus, Leptothrix sp. oral clone, Thiobacillus denitrificans, and Comamonadaceae bacterium, were also identified. Eight patients were found with mixed bacteria, with 2-4 bacteria per sample. The patients with fastidious bacteria such as Granulicatella adiacen and mixed bacteria were more likely to be older than 45 years (P < .05). CONCLUSION: A wide variety of bacteria, including some not previously reported associated with TMD, were identified in the synovial fluids from patients with TMD.

Opening of shortcut circuits between visual and retrosplenial granular cortices of rats.

Traveling neural signals may try to find suitable paths of propagation in cortical circuits. We examined the behavior of electrically evoked signals from primary visual cortex (Oc1) to granular retrosplenial cortex (RSG) in rat brain slices under caffeine application. With continued electrical stimulation, evoked signals propagated from Oc1 to RSG along the upper layer of the secondary visual cortex (Oc2) and agranular retrosplenial cortex (RSA), but on further continuation of stimulation, a new shortcut pathway along the deep layer between Oc2 and RSG was opened. Circuitry changes reduced the signal traveling time by about 40 ms. Cortical neural circuits between Oc1 and RSG may thus have the ability to open a shortcut circuit in a use-dependent manner.

Expression of receptor activator of nuclear factor-kappaB ligand in synovial tissue: comparison with degradation of articular cartilage in temporomandibular joint disorders.

OBJECTIVE: The present study was performed to investigate the correlations between expression of the receptor activator of nuclear factor-kappaB ligand (RANKL) in synovial tissue and the degrees of synovitis, degeneration of articular cartilage, and adhesions in patients with internal derangement (ID) of the temporomandibular joint (TMJ). STUDY DESIGN: Expression of RANKL, detected immunohistochemically, and the severity of arthroscopic features (synovitis, degenerative changes of articular eminence, and adhesion) in 30 patients with ID of the TMJ were assessed and the correlations between them were analyzed statistically. RESULTS: RANKL expression was detected in the cytoplasm of synovial lining cells, endothelial cells, and fibroblast cells. However, there were no correlations between RANKL expression in any cell type and the severity of arthroscopic features. CONCLUSION: These observations indicated that the cellular source of osteoclastic differentiation exists in TMJ with ID and may provide insight into the mechanism of osteoclast differentiation.

Expression of interleukin 8 in synovial tissues in patients with internal derangement of the temporomandibular joint and its relationship with clinical variables.

OBJECTIVES: The objectives of this study were to assay interleukin 8 (IL-8) in synovial tissues of the temporomandibular joint (TMJ) with symptomatic internal derangement, and to assess its relationship with clinical variables. STUDY DESIGN: Forty-six joints in 44 patients were examined using an immunohistochemical technique. As controls, 8 joints in 7 subjects with habitual dislocation without pain were also examined. RESULTS: IL-8 was expressed mainly in the blood vessels beneath the lining cells in 37 of the 46 joints (80%) with internal derangement and in 2 of the 8 control joints. The percentage of IL-8-positive cells was significantly higher in the internal derangement group than in the control group (P = .004). The percentage of IL-8-positive cells showed no correlation with joint pain or number of infiltrating cells. CONCLUSIONS: IL-8 was up-regulated in inflamed synovial tissues in patients with internal derangement. Because IL-8 has no significant correlation with clinical variables, IL-8 may play a secondary role in the pathogenesis of the internal derangement of the TMJ.

Prognostic factors in arthrocentesis of the temporomandibular joint: Comparison of bradykinin, leukotriene B4, prostaglandin E2, and substance P level in synovial fluid between successful and unsuccessful cases.

PURPOSE: To compare levels of bradykinin (BK), leukotriene B4 (LTB4), prostaglandin E2 (PGE2), and substance P (SP) between successful and unsuccessful cases of arthrocentesis of temporomandibular joint disorders (TMDs). PATIENTS AND METHODS: A total of 66 joints in 66 patients with TMDs who underwent arthrocentesis were evaluated in this study. Synovial fluid diluted with saline solution was aspirated from the superior joint compartment before arthrocentesis and their concentrations of BK, LTB4, PGE2, and SP were determined by enzyme-linked immunosorbent assay. The differences in the detection rate and concentration of each mediator between successful cases and unsuccessful cases of arthrocentesis were analyzed statistically. RESULTS: Arthrocentesis was successful for 77% (51/66) of the joints. The mean detection rate of LTB4 was significantly (P < .05) higher in the unsuccessful cases (47%) than in the successful cases (16%). The mean concentration of BK was significantly (P < .0005) higher in the unsuccessful cases (425 pg/mL) than in the successful cases (144 pg/mL). There was also a statistical correlation between the detection of LTB4 and PGE2 (P < .01). CONCLUSIONS: Increased levels of BK and LTB4 in the synovial fluid of patients with TMDs may indicate that arthrocentesis is less likely to be a successful treatment.