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

Mastication is one of the most important functions of the stomatognathic system and it can be performed either on the left side or right side. However, some people have each habitual chewing side, so imbalance of stomatognathic function between left and right is observed. This imbalance is supposed to reflect the relationship between the left and right elements of the stomatognathic system. Therefore, the analysis of this imbalance is very useful for assessing the stomatognathic system. The purpose of this study was to reveal the relationship between imbalance of stomatognathic function between left and right and asymmetry of craniofacial morphology, and the relationship between imbalance of stomatognathic function between left and right and center of gravity of upright posture. Eighty subjects without stomatognathic dysfunction were selected for this study. Electromyograms of the left and right masseter, anterior temporal, posterior temporal and anterior belly of digastric muscles during clenching were recorded, and mandibular movements during chewing were recorded. Analysis of imbalance between left and right was performed using functional parameters. Cephalograms (P-A) were taken for an analysis of craniofacial symmetry. The center of gravity of the upright posture was recorded using stabilograph. Analyses were performed to study the relationships between the parameters of stomatognathic function and craniofacial asymmetry, and the center of gravity of the upright posture. The results were as follows: 1. The analysis of functional parameters revealed some subjects showed imbalance between left and right sides. 2. On the side with wider craniofacial morphology as determined by some parameters, the activity of the masseter muscle during clenching showed tendency to be higher than that of the opposite, while the activity of the anterior temporal muscle showed tendency to be lower. On the side with longer craniofacial morphology, the activity of the anterior temporal muscle showed tendency to be higher than that of the opposite. 3. On the side where the center of gravity was shifted during clenching, the activities of the masseter, anterior temporal and posterior temporal muscles showed tendency to be higher than those of the opposite, and the durations of chewing cycle and opening phase showed tendency to be shorter. These results suggest that there are close relationships between imbalance of stomatognathic function and craniofacial asymmetry, and between imbalance of stomatognathic function and the center of gravity of the upright posture.

The study was aimed to investigate the effects of the occlusal contacts on chewing movements according to the changes of the mandibular first molar crown surfaces in 32 young adults. The study includes three components of the experiments as the control, various types of occlusal contact defects and the excessive conditions of occlusal surface contacts on the tooth. The chewing movement consistency was tested in the control study. The effects of the occlusal contact defects to the chewing movements, i.e., a periodontal mechanoreceptive defect (sensory block), a complete defect of coronal contact, partial defects (buccal or lingual cusp and inclination) of coronal surface, were then examined. Third, the effects of the occlusal deflective interference provided for the subjected tooth to the chewing movement was examined as the experiment in the excessive condition. The results obtained were as follows: 1. The consistency of segmental single tooth chewing movements was tested in the control study and revealed highly reliable among parameters of intra-day variance, but not enough for the inter-day variance in each subject. 2. The effects of occlusal contact defects were significant to the path and the rhythm of chewing movements in a poriodontal mechanoreceptive defect, complete coronal defect, cusp and inclination defects. 3. The effects of deflective occlusal interference were significant in the parameters, such as posterior deviation during closing path and inferior deviation of occluding point, prolonged duration in the closing phase, and shortening of duration in the occluding phase. It is suggested that either the occlusal defects or the interference conditions on one side of the first mandibular molar tooth may provide some effects to the chewing movements, and that appropriate occlusal contacts for the tooth may serve to maintain stabilized the path and the rhythm during chewing movements.

Mouth guards are effective to prevent traumatic injury in maxillofacial region during sports activities. This study was conducted to investigate the influence of wearing mouth guards on occlusal force distribution with the T-scan system. With comparison to the value of average occlusal force level per occlusal point (OFL) on natural dentition and wearing conventional full arch bite plane, following results were obtained. 1) Difference of OFL within the same dental arch became smaller when mouth guards were on. 2) Statistically significant difference in OFL was not found between two mouth guards with different hardness. 3) During three seconds clenching, OFL in posterior region changed great deal at the initiation but stayed at about the same level after that.

Statistical studies on numerical anomalies of teeth using orthopanthomograms had been attempted. In this paper, hyperdontia had been researched using 4009 orthopanthomograms of pedodontic patients. The tested were following: Male: Age 2-5 1036, 6-11 905, 12-22 Total 1963 Female: Age 2-5 1032, 6-11 985, 12-29 Total 2046 respectively. And 119 hyperdontia cases (143 teeth -1 tooth: 95 cases, 2 teeth: 24 cases) were found. Male: 84 cases 104 teeth (1 tooth: 64 cases, 2 teeth: 20 cases) Female: 35 cases 39 teeth (1 tooth: 31 cases, 2 teeth: 4 cases). Form supplemental teeth (normal form) deciduous teeth 4 teeth (4 anteriors containing 2-3 C in a case.) permanent teeth 32 teeth (anteriors: 28, premolars: 4) supernumerary teeth (abnormal form) deciduous cuspid like, conical 97 teeth (upper incisors) queer form 10 teeth (upper anteriors) Eruption line normal 85 teeth inversive 46 teeth horizontal 12 teeth Depth in alveolus Hyperdontia are classified in following: 1. in the alveolus deeper than permanent dentition in deciduous teeth period type I 1.7% in permanent teeth period type I' 23.5% 2. in the same depth of permanent dentition in deciduous teeth period type II 24.4% in permanent teeth period type V 9.2% 3. in the depth between permanent dentition and deciduous dentition type III 38.7% 4. in the deciduous dentition type IV 3.4% Type I, Type I', and Type III (total 63.9%) possibly belong to different teeth generation from deciduous and permanent teeth.

The modulation of dental pain transmission at the subnucleus caudalis of the trigeminal sensory nuclear complex (SpVc) was investigated in rabbits in vivo. The superficial layers of SpVc were perfused with artificial cerebrospinal fluid using a push-pull cannula system. Immunoreactive substance P (SP) released into the perfusates following electrical stimulation of the lower incisor pulp was measured. The obtained results were as follows. 1. An increase in the release of SP and [Met5]-enkephalin was observed by the electrical stimulation with 40 V. 2. The increase of SP release following electrical stimulation was inhibited by systemic administration of morphine (10 mg/kg i.v.) or local application of morphine (10(-6) M) to SpVc. The stimulus-evoked SP release was also inhibited by local application of [D-Ala2, Met5]-enkephalinamide (an analog of [Met5]-enkephalin; 10(-4) M). 3. Spontaneous release of serotonin (5-HT) into the perfusates was observed, while that of norepinephrine was not. Tooth pulp stimulation tended to increase the level of 5-HT. Systemic administration of morphine (10 mg/kg i.v.) and electrical stimulation of the nucleus raphe magnus (NRM) significantly enhanced the release of 5-HT. 4. The release of SP evoked by tooth pulp stimulation was inhibited by local application of 5-HT (10(-6)M) and electrical stimulation of NRM. These results suggest that there are two modulatory systems controlling the delivery of the ascending sensory message at the superficial layers of SpVc. One is an intrinsic mechanism associated with the segmental enkephalinergic system, the other is a descending monoaminergic system originating in NRM. It is also suggested that these two systems play an important role in producing the analgesic effect of morphine.

Statistical studies on numerical anomalies of teeth using orthopanthomograms had been attempted. In this paper, congenital hypodontia had been researched using 4009 orthopanthomograms of pedodontic patients. The tested were following; Male: Age 2-5 1036, 6-11 905, 12-22 Total 1963 Female: Age 2-5 1032, 6-11 985, 12-29 Total 2046 respectively. Many interesting results have been acquired, i.e. A. Congenital Hypodontia of Deciduous Teeth total 62 cases (78 teeth) 1 tooth defect--46 cases 2 teeth defect--16 cases B. Congenital Hypodontia of Permanent Teeth total 314 cases (566 teeth) 1 tooth defect--150 cases 2 teeth defect--115 cases 3 teeth defect--23 cases 4 teeth defect--18 cases 5 teeth defect--6 cases 6 teeth defect--0 case 7 teeth defect--1 case 8 teeth defect--1 case C. Defect Position deciduous teeth i2--83.3% permanent teeth P2--42.4% I2--36.4% D. Rare cases Symmetric defect (upper and lower): 2 cases, bisymmetric defect (right and left): 93 cases, symmetric and bisymmetric defect: 7 cases, defect of deciduous teeth and the succeeding permanent teeth: 37 cases, or in other expression, 2 B 1 case, 5/5 1 case, B 2 B B 1 case, 2 2 17 cases, 2 2 4 cases, 1 1 1 case, 3 3 1 case, 5 5 1 case, 3 2 2 3 1 case, 5 2 2 5 1 case, 5 4 4 5 1 case, 7 2 2 7 1 case, 7 3 3 7 1 case, 7 5 5 7 1 case, 7 5 2/2 2/2 5 7 1 case, 5/5 5/5 7 cases and 2B 2B 1 case, 3C 3C 1 case, B2 B2 8 cases, C3 C3 2 cases, 2B 5 cases, 2B 1 case, B2 10 cases, A1 1 case, A1 1 case, B2 6 cases' E5 1 case... In addition, the data have no significant difference in right and left, male and female. And for many reasons, we criticize the established theory (?) that congenital hypodontia is a systemic degeneration in human evolution. So we propose a following, simple and not incompatible concept--eventually congenital hypodontia except hereditary cases appear in many chances when development of dental germs (I2, P2, M3) is later than the surroundings and the space for it is remarkably deficient.

Sialoglycoprotein (SGP) having relatively high molecular weight was purified from human submandibular sublingual saliva by anion exchange chromatography on Q-Sepharose Fast Flow followed by gel filtration on Superose 6 prep grade. The molecular weight of SGP was estimated to be about 440,000 and the isoelectric points obtained by IEF-PAGE, ranged from 5.2 to 5.8. The purified SGP contained high compositions of glutamic acid, proline, glycine and aspartic acid which were calculated as about 57% of the total amino acids, and about 15% of sugars such as N-acetylneuraminic acid, galactose, fucose, mannose, N-acetylgalactosamine and N-acetylglucosamine. A panel of 23 murine monoclonal antibodies (MAbs; 8 IgG1, 15 IgM) directed against SGP was prepared. Although three protein components were detected by SDS PAGE, SGP specific MAb reacted intensely with a 60 kilodalton of protein component. Bacteroides gingivalis 381 showed high binding ability to SGP, but this interaction was inhibited by SGP specific MAb. To detect SGP in the pellicle formed on fragments of human dental enamel, SGP specific MAb were used. During the first hour of formation, rapid increase of SGP detected was observed, and it remained relatively unchanged between 1 and 24 h after beginning of pellicle formation. This work has suggested that SGP purified from submandibular-sublingual saliva is a main component of salivary pellicle on tooth surface and plays an important role in the interaction with oral bacteria including Bacteroides gingivalis.