Search

Aim The purpose of this pilot prospective cohort study was to investigate the effects of parafunctional masseter muscle activity on periodontitis progression among patients receiving supporting periodontal therapy (SPT). Materials and methods We collected data of patients treated at Okayama University Hospital from August 2014 to September 2018. The progression group was defined as patients with ≥2 teeth demonstrating a longitudinal loss of proximal attachment of ≥3 mm during the 3-year study period and/or at least one tooth extraction due to periodontitis progression. Surface electromyography of masseter muscles at baseline was continuously recorded while patients were awake and asleep. Results We analysed 48 patients (36 females) aged 66.8 ± 9.1 years (mean ± SD). The rate of parafunctional masseter muscle activity during waking hours and sleeping hours at baseline was 60.4% and 52.1%, respectively. Cox's proportional hazards regression model showed that the incidence of periodontitis progression was significantly associated with number of teeth present (p = 0.001) and parafunctional masseter muscle activity during waking hours (p = 0.041). Conclusion Our results suggest that parafunctional masseter muscle activity during waking hours is a risk factor for periodontitis progression among patients receiving SPT.

We investigated the characteristics of grouped discharge (GD) waveforms obtained from long-term masseter electromyogram (EMG) recording in 6 female temporomandibular disorder (TMD) patients with myofascial pain and 6 healthy females. The EMG measurement was performed from the morning of the experiment day until the subject woke up the next day. We observed a significantly larger number of GD waveforms in the TMD group compared to the control group (p=0.002). Our results indicate that the existence of GD waveforms in masseter EMGs might be a predictor of future TMD with myofascial pain.

BACKGROUND Fatigue is an important factor for muscle strengthening in rehabilitation medicine. Frequency analysis has been regarded as the gold standard for muscle fatigue assessment in surface electromyography (EMG). However, there are no experiments quantifying fatigue with grouped discharge (GD), which is one of the historical phenomena observed in patients having fatigue, by using high sampling rate recording of EMG. OBJECTIVE To investigate the effect of fatigue, which is induced by repeated posterior tongue lift movement (TLM), on the occurrence of GD peaks, thus, to provide possible basis as a parameter for future fatigue evaluation. METHODS Nineteen healthy adults (9 men and 10 women) participated in this study. The muscle fatigue protocol consisted of repetitive posterior TLM and maximum voluntary contractions (MVC). Bilateral N-EMG (Neck surface EMG for measuring the muscle activity of the posterior tongue) was recorded. RESULTS Subjective tongue fatigue at the end of the protocol was significantly higher than at beginning throughout the muscle fatigue protocol (p

Purpose To design an efficient tongue prosthesis with reproducibility and to objectively evaluate improvement in speech function. Methods A silicon anatomical artificial tongue (AT) and a flat surface artificial tongue system (FTS) were used in our study. Twenty healthy participants (10 males and 10 females, 26.3 ± 1.8 years) were fitted with a tongue movement suppression appliance (TSA) that fit the dental arch to simulate the glossectomy condition. TSA, TSA + FTS, and TSA + AT simulated the state of glossectomy patients without artificial tongue, with normal artificial tongue, and newly designed artificial tongue, respectively. Three speech intelligibility tests were performed for each of the following conditions: pronouncing 100 Japanese monosyllables, 40 Japanese words, and reading a short story. One-way ANOVA, Wilcoxon signed-rank test, and Tukey-Kramer post-hoc test were used for statistical analyses. Results Significant differences were observed for 100 Japanese monosylla bles and 40 Japanese words between the TSA + FTS, TSA, and TSA + AT conditions (p ‹ 0.05). Regarding the speech intelligibility test for reading a short story, the TSA + FTS condition resulted in a significantly higher speech intelligibility than the TSA and TSA + AT conditions (p ‹ 0.05). Conclusions A flat surface artificial tongue system contributed to the improvement in speech function. This structure can be easily used in cases where conventional artificial tongue are applicable, regardless of variation in the oral condition; thus, making it a widely applicable treatment option for glossectomy patients.

To provide a scientific data related to the tonic activity of masseter muscle in subjects with and without history of orofacial pain during their normal daily life.Thirty-three subjects were divided into two groups, a pain history group (PHG) and a non-pain history group (non-PHG), based on their responses to the Research Diagnostic Criteria for Temporomandibular Disorders questionnaire. After excluding four subjects with incomplete recordings, full-day masseter muscle surface EMGs of 29 subjects (10 men, 19 women; mean age 24.1 years) were analyzed. Tonic episode (TE) was defined as continuous EMG activity with a duration at least 2s with intensities above twice the baseline noise level. TEs were classified into 6 strength categories (7.5%, 7.5-10%, 10-15%, 15-25%, 25-40% and40% of the maximum voluntary clenching (MVC)). The mean duration of activity observed in the non-PHG+2 SD was adopted as a cutoff for identifying sustained TE.During waking hours, the incidence of sustained TEs was significantly higher in the PHG than in the non-PHG (p0.05). The incidence and total duration of sustained TEs were significantly higher in the PHG than in the non-PHG at intensities of 7.5-10% MVC, 10-15% MVC, and 15-25% MVC (p0.05). No significant difference was observed during sleep.Within the limitations of this study, it would be concluded that sustained TEs may have a correlation with orofacial pain and the intensity range of 7.5-25% MVC would be an important range for future clenching studies.

Asian and African elephants are frequently afflicted by foot disorders that can be very challenging to manage even with aggressive therapy. Such conditions may have indirect life-threatening effects. Mohs' paste (zinc chloride based escharotic agent) was used to treat a female Indian elephant (Elephas maximus indicus) aged 39 years with foot disorder at Kanazawa Zoological Gardens. Degenerated hyperplastic tissue was observed inside the hoofs of digits 2 and 5. Mohs' paste was applied on the lesions, which coagulated the hyperplastic tissue and restrained its proliferation. Subsequently, the hyperplastic tissue could be trimmed with little pain, and the disorder became manageable. Mohs' paste treatment was effective and is expected to be an alternative treatment for hoof disorder.

The histopathological, immunohistochemical, and ultrastructural morphologic characteristics of a tumor in the subcutaneous tissue of the chest of a 19-year-old female Japanese macaque were investigated. Consequently, the mass was diagnosed as a malignant mast cell tumor (MCT). Tumors were present in both mammary gland portions of the anterior thorax. Both tumors showed the same histopathological findings. The tumor tissue was defined by the presence of delicate connective tissue, and the tumor cells grew in a cord-like or cobblestone pattern. The tumor cell cytoplasm was very clear. The nuclei were relatively uniform and the cells showed a low nucleus-cytoplasm ratio. The cytoplasmic granules stained blue with Alcian blue and eosinophils had infiltrated into the tumor tissue. Furthermore, immunohistochemical analysis revealed that the tumor cell membrane was positive for the anti-c-kit antibody. In ultrastructural morphologic analyses, all tumor cells showed a rich cytoplasm and, occasionally, granules wrapped in a limiting membrane of high electron density. The tumor cells had metastasized to the axillary lymph nodes, the kidney, and the peritoneum. Based on these results, the mass was diagnosed as a malignant MCT originating from the subcutaneous tissue of the chest. Since cases of MCTs in macaques are very rare, this report presents important new knowledge of neoplastic lesions in this species.

Asian and African elephants are frequently afflicted by foot disorders that can be very challenging to manage even with aggressive therapy. Such conditions may have indirect life-threatening effects. Mohs’ paste (zinc chloride based escharotic agent) was used to treat a female Indian elephant (Elephas maximus indicus) aged 39 years with foot disorder at Kanazawa Zoological Gardens. Degenerated hyperplastic tissue was observed inside the hoofs of digits 2 and 5. Mohs’ paste was applied on the lesions, which coagulated the hyperplastic tissue and restrained its proliferation. Subsequently, the hyperplastic tissue could be trimmed with little pain, and the disorder became manageable. Mohs’ paste treatment was effective and is expected to be an alternative treatment for hoof disorder.

This study was conducted to investigate whether the masseter muscle activity shows any specific pattern in relation to the severity of periodontitis.Sixteen subjects with no or mild periodontitis (NMP group) and 15 subjects with moderate or severe periodontitis (MSP group) were enrolled. Plasma IgG antibody titer was examined using Porphyromonas gingivalis as a bacterial antigen. Surface electromyography (EMG) of the masseter muscles was continuously recorded using an ambulatory surface EMG recording device while patients were awake and asleep. Masseter muscle activity was analyzed using intensities of 5%-10% maximal voluntary clenching (MVC), 10%-20% MVC, and20% MVC. Furthermore, EMG levels of 20% MVC were adopted as the threshold for analysis of phasic, tonic, and mixed EMG activities. The cumulative duration of masseter muscle activity and bruxism episodes was calculated as duration per hour.There was no significant difference in plasma IgG antibody titers against P. gingivalis between the NMP and MSP groups (p = 0.423). During waking hours, the duration of masseter muscle activity with an intensity of20% MVC was significantly longer in the MSP group than in the NMP group (p = 0.037). During sleeping hours, the duration of masseter muscle activity at all MVC intensities was significantly longer in the MSP group than in the NMP group (all p 0.05). Additionally, the duration of phasic and mixed episodes was significantly longer in the MSP group than those in the NMP group while both awake and asleep (all p 0.05).The results of this study suggested that masseter muscle activity might be related to the severity of periodontitis.

In Rhinocerotidae, there are very few reports of tumors and no reports of a mixed tumor. This paper reports the case of a male 33-year-old southern white rhinoceros. Grossly, there were two masses in the coelomic cavity and solid nodules in the liver. Histologically, all tumors had a biphasic pattern that consisted of malignant epithelial cells (cytokeratin- and E-cadherin-positive) and non-epithelial cells (vimentin-positive) with cartilage. In this case, the prostate could not be identified, and instead, the largest tumor mass was present at that site. Furthermore, since structures regarded as the prostate duct remained in this tumor, we considered that this tumor was very likely to be of prostate gland origin. This case is the first report of carcinosarcoma in Rhinocerotidae.

Aims: To assess the influence of clenching side and location (ie, tooth) on the bite force necessary to induce pain or discomfort in patients with unilateral anterior disc displacement (ADD) of the temporomandibular joint (TMJ). Methods: A total of 17 patients with unilateral ADD diagnosed clinically and with magnetic resonance imaging were included. A bite force meter was positioned at each of four experimental positions: the mandibular first premolars and first molars, bilaterally. Subjects were instructed to clench on the bite force meter until they felt pain or discomfort in the orofacial area and to report the location of the pain. Differences in pain location (ADD side versus contralateral side) and in the bite force thresholds for eliciting pain or discomfort were assessed by means of the paired t test and Wilcoxon signed-rank test. Results: Only 18% of subjects (3 out of 17) reported pain in the TMJ with ADD during clenching at the ipsilateral molar, whereas 65% (11 out of 17) reported joint pain during clenching on the contralateral molar (P = .005). At the molars, the mean ± standard deviation bite force necessary to induce pain was 241.2 ± 135.5 N on the side with ADD and 160.9 ± 78.0 N on the contralateral side. The mean molar bite force necessary to induce pain on the side with ADD was significantly higher than that on the contralateral side (P = .002). Conclusion: Patients with unilateral ADD had fewer reports of TMJ pain and discomfort when they were molar clenching on the ipsilateral side compared to molar clenching on the contralateral side.

The activity of the lateral pterygoid muscle has been regarded to be related to the pathological condition of the temporomandibular joint (TMJ) in the craniomandibular disorders. Because the lateral pterygoid muscle is a deep muscle, a needle electrode is necessary for EMG recordings. The purpose of this study was to establish a non-invasive method for the evaluation of muscle activity of the lateral pterygoid muscle using mechanomyogram (MMG). In three male subjects, surface electromyogram (EMG) in the left masseter muscle, left anterior and posterior belly of the temporal muscle, left anterior belly of the digastric muscle and needle EMG of the inferior head of the lateral pterygoid were recorded during mandibular movement tasks simultaneously with the MMG derived from a condenser microphone in the external ear canal. There were significant positive correlations between the needle EMG signal of the lateral pterygoid muscle and the MMG signal for the tasks of static jaw opened position of 30 mm of interincisal distance (p = 0.000, R(2)=0.725), static jaw opened position of 40 mm of interincisal distance (p = 0.000, R(2) = 0.753), 5 mm protruded mandibular position (p = 0.000, R(2) = 0.653), the most protruded mandibular position (p = 0.000, R(2) = 0803). On the contrary, for the task of maximal clenching, there was no significant correlation between the EMG signal of the lateral pterygoid muscle and the MMG signal. These results suggest that the activity of the lateral pterygoid muscle could be evaluated by the MMG signals recorded in the external ear canal, unless jaw closing major muscles show active contraction.

Accepted March 30, 2015. DOI: 10.7883/yoken.JJID.2015.094 *Corresponding author: Mailing address: Laboratory of Acute Respiratory Viral Diseases and Cytokines, Department of Virology III, National Institute of Infectious Diseases, Murayama Branch, 4-7-1 Gakuen, Musashimurayama, Tokyo, 208-0011, Japan. Tel: +81-42-561-0771, Fax: +81-42-567-5631, E-mail: shirato@nih.go.jp Jpn. J. Infect. Dis., 68, 256–258, 2015

The purpose of this study was to reveal the relationship between chewing-side preference and anterior disc displacement (ADD) of the TMJ. Thirty-two healthy subjects with ages ranging from 26 to 34 years were selected from volunteer students at the Okayama University Dental School. Subjects were asked to chew freely with two kinds of test foods, beef jerky (hard food) and chiffon cake (soft food), thus expecting different amounts of mechanical loading on the TMJ. One, 4, and 7 s after starting the mastication, subjects were asked to open their mouth momentarily to have a digital image of their mouth taken. The bolus placement area was measured by processing the digital images, calculated as the number of pixel of bolus area. Area asymmetry index was used for the determination of preferred chewing side (PCS). Oblique sagittal MRI scanning in the closed mouth position was taken to evaluate the articular disc position. In asymptomatic subjects with ADD, a significant predominance of the PCS on the ipsilateral side of ADD was observed during the mastication of hard food. On the contrary, no correlation was found between unilateral ADD and PCS for the soft food. From the results of this study, it is suggested that ADD is the associating factor of PCS for hard food. Therefore, it would be necessary to break down the concept of PCS into at least two categories, one for hard food and one for soft food, considering the mechanical loading on the TMJ.

Aims: Although body posture in relation to the dental condition has been of great interest in the dental profession, rumination bias has been a substantial obstacle to achieving a reliable objective evaluation of the intrinsic body posture. The aim of this study was to establish a posture control protocol that would minimize the effect of bias.Methodology: Fifteen healthy male volunteers (23–33 years of age) participated in this study. The posture movement was recorded for 10 seconds by a three-dimensional motion capture system. The experiment was performed on four different days.Results: The posture was most stable at 4–5 seconds after the start of the front bulb gaze (the mean coefficient of variation ranged from 0·1 to 44·1). The intraclass correlation coefficients for four days were 0·871–0·975 (P≤0·001).Conclusions: It was concluded that the use of this measurement method helped in producing a reliable intrinsic standing posture where unbiased evaluation of the effect of any intervention on t...

A case of malignant melanoma in the conjunctiva of the eyelid of a captive 13-yr-old female fallow deer (Dama dama) was studied. The black tumor that protruded to the palpebral conjunctiva of the right lower eyelid consisted of an infiltrative growth of melanin-containing neoplastic cells with marked cytological atypia. The tumor involved the conjunctiva of the right lower eyelid and infiltrated to the conjunctival epithelial layer, but did not reach the palpebral skin. Numerous mitotic figures and lymphatic invasions were observed. This is a very rare case of a malignant melanoma arising from the palpebral conjunctiva in a wild ruminant.

Previous work suggests a relationship between sustained low-level tooth clenching and the aetiology of myogenous temporomandibular disorder (TMD) pain. This study aimed to establish a reliable system with which to evaluate low-level electromyographic (EMG) activity related to low-level tooth clenching while discriminating speech activity, which is one of the most common facial muscle activities to be discriminated from low-level clenching. This device should facilitate the clinical evaluation of awake muscle activity in TMD patients. Eight female and eight male subjects (38.9 ± 11.3 years) participated in the study to evaluate the validity of estimation of speech duration. Actual speech duration was defined by one examiner by pointing out the timing of beginning and end point of each speech on wave-editing software. Speech duration, as detected by a voice sensor system, which was activated by a voice loudness of 54.71 ± 5.00 dB, was significantly correlated with the above actual speech duration (P < 0.01, R(2) = 0.9935). An actual recording with the system was carried out in one TMD patient and one healthy volunteer and revealed that the duration of diurnal EMG activity higher than 5% MVC was 1649.16 s and 95.99 s, respectively. As the voice sensor system adopted in this study could define the exact onset and offset of each segment of speech, EMG activity during speech could be precisely discriminated. The results of this study demonstrate that the EMG system with voice sensor system would be an effective tool for the evaluation of low-level masticatory muscle activity.

The objectives of this study were (1) to establish a reliable method for detecting the force threshold of the tooth tactile sensation while avoiding experimenter bias and (2) to examine the effect of occlusal force loading on the threshold for impulsive force stimulation in subjects with normal dentition. Twenty volunteers participated in this study (10 males and 10 females; mean age, 26.6 ± 2.9 years). To simulate the bite force during occlusal tapping, a force-loading device was designed to exert impulsive force to the occlusal surface in the direction parallel to the tooth axis. The impulsive force detection threshold of the periodontal sensation was measured before and after loading 98 N of occlusal force on the left upper first molar for 1 min. Transient mechanical loading of the upper first molar caused an increase in the absolute threshold for impulsive force. This increase did not vanish immediately, and the increment of the threshold was maintained during the remainder of the experiment. A computer-controlled method for the evaluation of tooth tactile sensation using impulsive stimulation was established. Transient occlusal force loading parallel to the tooth axis increases the threshold of periodontal sensation for mechanical impulsive stimulation.

The aim of the present study was to investigate whether changes in body temperature are related to the ovarian cycle in elephants. Rectal, tongue or fecal temperature was measured for 2 Asian and 5 African elephants using an electric thermometer. Evaluation of ovarian cycles was based on the changes in serum or fecal progestin. The mean +/- SD values of the rectal, tongue, and fecal temperatures were 36.3 +/- 0.3 (2 Asian), 36.2 +/- 0.5 (1 African) and 36.5 +/- 0.3 C (4 African), respectively; the fecal temperature was the highest of the 3 temperatures (P

In 3 adult female cheetahs, induced-superovulation treatment was conducted, by means of 200 IU of pregnant mare serum gonadotropin (PMSG) and 100 IU of human chorionic gonadotropin (hCG) 80 hr after PMSG. The administration of PMSG created a sharp increase in the estradiol-17beta concentration, resulting in 232 pg/ml 8 hr later in one specimen out of three. The hCG administration showed an increase in the progesterone concentration of 2.29 ng/ml 46 hr later. In addition, after direct observation of the ovary surface by laparoscopy, 5 follicles in the right ovary over 2 mm in diameter, and 7 corpora lutea (5 in the right ovary and 2 in the left) were found. It is assumed that ovulation can be induced with hCG after 80 hr on PMSG during a cheetah's diestrus or proestrus.