[Osaka Daigaku shigaku zasshi] The journal of Osaka University Dental Society最新文献

The magnitude of tooth mobility has been frequently used for evaluating biomechanical response of the periodontal tissue to applied forces. However, tooth mobility during orthodontic tooth movement has not been measured. The purpose of this study was to investigate changes in biomechanical property of the periodontal tissue during canine retraction, in terms of tooth mobility. The upper canines on both sides of ten orthodontic patients were moved in the distal direction for about four weeks with an initial force of 200 gf. An amount of tooth movement and a magnitude of tooth mobility were measured every 3 or 4 days during retraction. A distally directed force up to 500 gf was continuously applied to each canine and tooth mobility was measured with a noncontact type of eddy current displacement sensor. A two-dimensional finite element model was constructed and displacements of the finite element model were calculated with various Young's moduli in loading with a 100 gf force in the distal direction. In comparison with the magnitudes of the tooth mobility, Young's modulus of the periodontal membrane before retraction and the influence of the biomechanical factors on changes in tooth mobility were investigated. The tooth movement curve was divided into three phases; an initial phase, a lag phase and a post-lag phase. The magnitudes of tooth mobility at the initial phase were significantly larger than those before retraction within the range of 250 gf to 500 gf and these magnitudes decreased during the lag phase. The magnitudes of tooth mobility at the post-lag phase significantly increased, within the range of 50 gf to 500 gf, than those before retraction. As a result of curveliniar regression analysis, the tooth mobility curves approximated to delta = AFB, where delta and F denote tooth mobility and force respectively. The coefficients A and B changed according to the phases of tooth movement. An inclination of the tooth mobility curve expressed by a tangent at the 400 gf force was the largest at the initial phase, and this inclination at the 100 gf force was the largest at the post-lag phase. Young's modulus of the periodontal membrane before retraction was determined to be approximately 35 gf/mm2 and Young's modulus of the periodontal membrane was the most important factor on the increase of tooth mobility. Tooth mobility significantly varied associated with tooth movement. It was indicated that biomechanical property of the periodontal tissue changes in response to each phase of tooth movement. In particular, Young's modulus of the periodontal membrane decreased at the post-lag phase of the orthodontic tooth movement.

The expert system for designing removable partial dentures has a great potentiality for clinical and educational use. The system sorts out several solutions for clinical problems with the aid of logic and data bases stored in the memory bank. The most important part of this system is the inference engine. Production system and frame system are often used as the inference engine. The purpose of this report was to compare different types of inference engine in practical situations. Following conclusion were obtained. 1) Since each type of inference engine has its own advantages and disadvantages, one has to select most suitable one for the purpose of the system. 2) One must select the inference engine type which will help potential user's understanding.

The bite plane therapy has been one of the most useful treatment methods for patients with temporomandibular joint (TMJ) dysfunction. But the bite plane usually causes esthetic and articulation disturbances and it is occasionally difficult to use during mastication. The authors have fabricated a new type of bite plane, named occlusal splints, which covers each side of the premolars and molars. The occlusal splint was constructed by a hard-resin for the occlusal part and cast clasps for the retentive part and these parts were adhered after a pre-treatment of metal by the use of a silane coupling agent (Silicoater system). The patient was a 35 year-old man, with a chief complaint of left side reciprocal TMJ clicking. The anterior repositioning type of bite plane was applied for the treatment with the diagnosis of anterior disk displacement with reduction. But he complained of esthetic and articulation disturbances especially during working and eating. After four months we fabricated an occlusal splint that can be used for a long period of time. The patient was satisfied to use this occlusal splint and no symptoms of TMJ dysfunction were found with this appliance. It is suggested that the occlusal splint consisting of a hard-resin and cast clasps is a useful appliance especially for the purpose of use during working and eating, and for evaluating the properness of mandibular position.

The present study was intended to clarify the mechanical contraction properties and to investigate roles in velar movements of the tensor veli palatini (TVP) muscle in dogs. The dogs used in the experiments were anesthetized intra-peritoneally with sodium pentobarbital. Experiment I: Tension of the TVP muscle was induced by stimulation to the motor nerve and was recorded: 1. The contraction time and half relaxation time of maximal isometric twitch of the muscle were 13.7 +/- 0.7 msec and 10.4 +/- 1.2 msec, respectively. 2. A clear summation of muscle contractions was obtained with stimulation at 20 Hz with maximal tetanic tension at 90 Hz. The tetanus twitch tension ratio was found to be 10.7 +/- 1.1. Experiment II: The role of the TVP muscle in velar movements was investigated from the standpoint of upper airway patency. In addition, the effect of fracture of the pterygoid hamulus and transection of the TVP muscle at the pterygoid hamulus on velar movements were also investigated. The results indicated the following: 1. Upon electrical stimulation of the motor nerve of the TVP muscle, the anterior part of the soft palate was displaced laterally with the subsequent expansion of the epipharynx. 2. Negative pressure in the nasal cavity was observed with the respiratory activity of the TVP muscle after tracheostomy, but not in the oral cavity. 3. Contraction of the TVP muscle decreased nasal airway resistance when intranasal airflow was confirmed at levels higher than 120 ml/sec. 4. After fracture of the pterygoid hamulus, contraction of the TVP muscle produced expansion of the epipharynx but less than that prior to the treatment. The fracture did not change nasal airway resistance. 5. After transection of the TVP muscle at the pterygoid hamulus, the contraction of the TVP muscle did not produce any velar movements. Neither expansion of the epipharynx nor changes in nasal airway resistance were observed.

To reveal the functional significance of fiber connections from the cortical taste area (CTA) to the parabrachial nucleus (PBN), a combined study with neuroanatomical and electrophysiological techniques were performed on male Wistar rats anesthetized with urethane. The results were as follows: 1. Tracing of WGA-HRP showed that the fibers connecting the CTA and PBN passed through the central tegmental field (CTF). 2. Injection of glutamate into the PBN and electrical stimulation of the PBN elicited copious salivary secretion. Electrolytic lesion of the CTF and ibotenic acid lesion of PBN neurons diminished salivary secretion induced by electrical stimulation of the CTA. These results suggest that some PBN neurons receive inputs from the CTA and send axons to the lower brain stem for salivary secretion. 3. Electrical stimulation of the CTA induced both salivary secretion and jaw movements. Lesions of the CTF at the inferior colliculus level inhibited the cortically induced salivary secretion, but did not affect the jaw movements. On the contrary, lesions of the pyramidal tract (PT) at the same level inhibited jaw movements, but did not affect salivary secretion. These results suggest that corticofugal fibers concerned with salivary secretion pass through the CTF and those concerned with jaw movements pass through the PT. 4. Of 61 PBN neurons that responded to taste stimuli, 14 (23%) showed facilitatory (F), 11 (18%) facilitatory-inhibitory (F-I), 1 (2%) inhibitory-facilitatory (I-F), and 2 (3%) inhibitory (I) responses to single pulse stimulation of the ipsilateral CTA. Repetitive CTA stimulation induced F responses in 16 (33%) and I responses in 6 (12%). This proportion of F and I responses was essentially the same in any groups of neurons classified by responsiveness to taste stimuli.

A case of lymphoepithelial cyst of the upper neck is presented. The patient was a 77-year-old woman. After her lesion was extirpated under clinical diagnosis of salivary gland tumor, identified as lymphoepithelial cyst (so-called branchial cyst). Histopathologically salivary gland was observed in the cyst wall composed of lymphoid tissue and was demonstrated highly active amylase-enzyme (S type) in the cyst fluid. These findings are convicted that our case originates ductal epithelium entrapped in cervical lymph node (inclusion theory of Bhaskar).

The purpose of this study is to investigate the mechanism on enhanced hemagglutination caused by neuraminidase from Bacteroides in an aspect of zeta-potential levels on erythrocytes and inhibitors on hemagglutination activity. The neuraminidase from the culture medium of Bacteroides loescheii ATCC 15930 was purified by ultrafiltration followed by DEAE-Sephacel anion exchange chromatography, fast protein, polypeptide, polynucleotide, liquid chromatography using Mono P column and finally high performance liquid chromatography using Shim-pack Diol-300 column. The purified enzyme appeared to be homogeneous by analytical polyacrylamide gel electrophoresis. The molecular weight was measured to be approximately 87,000 and the optimal pH was at 4.8. The isoelectric point was at 5.1. The enzyme showed relatively high specificity toward the linkage of NANA alpha (2----3) oligosaccharides and glycoproteins, and less toward the linkage of NANA alpha (2----6), and/or NANA alpha (2----8) oligosaccharides. When the human erythrocytes were treated by the purified enzyme, hemagglutination activities of some strains of Bacteroides gingivalis, Bacteroides denticola and Bacteroides intermedius were enhanced. Hemagglutination inhibition experiments using B. gingivalis 381 showed that the activity of hemagglutination was strongly inhibited by the arginine-containing peptides especially salmine derived from salmon, although the activity was unaffected by the sugars, amino acids and divalent cations such as Ca2+, Mn2+ and Mg2+. The zeta-potential level on asialo-erythrocytes treated by purified enzyme was considerably decreased compared to that of sialo-erythrocytes. It seems likely that the mechanism on hemagglutination by the B. gingivalis 381 may be involved in electrochemical affinity between the erythrocytes and bacterial cells with the reduction of zeta-potential, and in arginine-containing peptides as receptors of ligand-binding on erythrocytes.

The radial forearm flap, or the forearm flap, is called "Chinese flap" for its development of the chinese doctors, and is originally designed for the correction to the post-burn contraction of the face and neck. The radial forearm flap is one of the fasciocutaneous flap, supplied by the radial artery, and transferred as a single-stage reconstruction micro-surgically. In oral and maxillofacial region, the deltopectral flap (D-P flap) and the pectralis major myocutaneous flap (P-M-M-C flap) are mainly used for the reconstruction. These flaps, however, are sometimes too bulky and limited to transfer, and more require two-stage operations. On the other hand, as the forearm flap being thin and pliable, some doctors use this flap micro-surgically at single-stage free flap reconstruction. Before two years, we have begun to transfer the radial forearm flap for the intra-oral reconstruction. The operation method is as follows. Design and Elevation of the Radial Forearm Flap 1. Using the ultrasonic doppler flow meter, the radial artery and the subcutaneous forearm veins are marked on the skin. 2. The flap is designed 20% larger according to the pattern to be reconstructed, with the distal section of the radial artery as an axis on the forearm and the median vein of forearm inclusively. 3. Before the operation, Allen test must be performed in order to determine whether the hand will survive without a radial arterial in-put. 4. The operation is performed with a arm tourniquet. The margin of the flap are incised down to the deep fascia, isolating and preserving the proximal subcutaneous veins as required.(ABSTRACT TRUNCATED AT 250 WORDS)

Chewing movement is one of the most important functional and physiological jaw movements, and it is coordinated by the three elements of the functional occlusion system (teeth, TMJs and masticatory muscles). However, the relationship between chewing movement and these elements has not been clarified. The purpose of this study was to investigate the relationship between chewing movement and the activity of the masticatory muscles which directly control jaw movements. 25 subjects with normal stomatognathic function, 5 patients with MPD syndrome (muscle dysfunction group) and 5 patients with unilateral TMJ internal derangement (TMJ dysfunction group) were selected. 6 gums with different hardness were used as the test bolus. Sirognathograph Electromyograph Analysing System was used to simultaneously record chewing movements and electromyograms of the right and left masseter, anterior temporal, posterior temporal and anterior belly of digastric muscles. Using the analysing software which was developed for this study, chewing movements and muscle activities were analysed. The results were as follow; A. In normal subjects 1. Gum hardness influenced durations of the closing and occluding phases, maximum opening and closing speed, opening degree and deviation of opening and closing path. 2. Gum hardness influenced muscle activities except of the time factors of digastric bursts. 3. Durations of the closing and occluding phases were found to be related with the elevator muscle activities. Maximum closing speed was related with the masseter and anterior temporal muscle activities. Deviation of closing path was related with the anterior and posterior temporal muscle activities. B. In abnormal subjects 1. The changes mainly observed in the muscle activities were found to be significantly different between the muscle dysfunction group and normal group. Similarly, the changes mainly observed in the chewing movements were different between the TMJ dysfunction group and normal group. 2. When compared with the relationships in normal subjects, changes were observed in the relationships for closing movement in the muscle dysfunction group. In contrast, changes were observed in the relationships for opening movement in the TMJ dysfunction group. From the results, close relationships were found between chewing movements and muscle activities, and were characteristically influenced by stomatognathic dysfunction.

The localization of the rabbit pharyngeal montoneurons in the nucleus ambiguus and peripheral courses of their axons were investigated using injection of retrograde labeling tracers, i.e., HRP and nuclear yellow, into the individual pharyngeal muscles or using the injection in conjunction with intracranial severing of either the vagal or glossopharyngeal rootlets. The nucleus ambiguus of the rabbit was divided into four groups of neuron, of which the following two, the compact cell group (CoG) and the medial scattered group (SGm), were pertinent to the pharyngeal montoneurons. The CoG is a group formed by a compact arrangement of the smallest neurons and situated in the rostral half of the nucleus ambiguus. The SGm is a group formed by a scattered arrangement of slightly larger neurons in the rostral one-third of the nucleus and located medial to the CoG. The labeled stylopharyngeal motoneurons occupied the rostral portion of the SGm at a level from about 2800 to 3100 microns rostral to the obex. They were completely abolished by severing the glossopharyngeal rootlets, in contrast to no change of labeled neuron number when severing the vagal rootlets. Thus, all axons of the stylopharyngeal motoneurons were concluded to traverse the glossopharyngeal rootlets. The labeled palatopharyngeal motoneurons were found in the caudal portion of the CoG at a level from 500 to 1900 microns rostral to the obex, with their number being numerous at the caudal one-third of CoG, 500 to 1300 microns. All their axons traversed the vagal rootlets. The labeled pharyngeal constrictor motoneurons were found at almost all rostrocaudal levels of CoG, 500 to 2900 microns rostral to the obex, with their number being numerous in its middle one-third level. Although motoneurons of the superior constrictor, those of the middle constrictor, and those of the thyro and cricopharyngeal muscles composing the inferior constrictor overlapped rostrocaudally in location, their ranges of appearance had a tendency of arranging rostrocaudally in that order. At the middle one-third level of CoG, in which the CoG was subdivided into two subgroups, dorsomedial and ventrolateral, the superior and middle constrictor motoneurons were located in its entire portion. The majority of axons of the pharyngeal constrictor motoneurons traversed the vagal rootlets, though a few axons whose somata lay in the rostral portion of the CoG traversed the glossopharyngeal rootlets.