Human mandible is supported of its spatial position in the I.P. through the four occlusal segments in molar and premolar regions, which are called as the “Supporting zone of the mandible” (Steinhardt, 1952). No one has been able to estimate how prompt and how much the mandibular position would change after the loss of concerned occlusal contacts just in the free-end saddle conditions till today. We have measured and analyzed the chronological change of the mandibular position under the experimental condition with two men in this present study. The results obtained were as follows : (1) Immediate re-movable partiale denture (RPD.) in the free-end situation was able to hold the mandibular position after the extraction of the molar teeth. (2) After disuse of the immediate RPD., it happened the prompt loss of the intermaxillary distance between the upper and lower jaws. (3) The mandibular positions in the IP. were changed markedly according to the scheduled and experimental conditions. The lability of the conditioned change were often seen with at least two types between the loss of occlusal contacts in the second premolar and in the first molar.

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The purpose of this investigation is to establish a diagnostic model applicable for jaw deformities according to the classification based on quantitative discrimination of craniofacial patterns in patients diagnosed as being indispensable with surgical orthodontic treatment. Materials used in this study were lateral roentgenographic cephalograms of 74 female adults from surgical orthodontic cases registered at the Orthodontic Clinic, Showa University Dental Hospital. Data were put to the principal component analysis, the cluster analysis and the discriminant analysis.
The results were as follows.
1. The principal component analysis of craniofacial complex showed the first component was related to lower facial height. The second component was related to the anterior border on the apical base of maxilla as well as mandible, mandibular length and mandibular rotation.
2. The cluster analysis could classify each group into three different types, namely Short face type, Long face type and Mixed type.
3. The linear discriminant analysis, applied to these three groups, validated five variables (SNA, Occlusal plane angle, Mo-Mi', N-ANS, Pog'-Go) sufficient for discriminating groups with 90.5% correctness.
It is presumed this classification is available for “Selection of Similar Cases” on planning surgical orthodontic treatment.

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The crown dimensions were compared between dp4 and M1 on the maxilla in Tupaia glis. Although the dp4 resembled the MI in pattern, the structure of the dp4 was more primitive than that of the Ml. The dp4 was 86.707% of the Ml in the module. The mean values of the crown dimensions were larger in the MI than in the dp4 and these differences were significant statistically except for the distal buccolingual diameter (DBL). The DBL was slightly larger in the dp4 than in the Ml, but the difference was not significant. More pronounced differences between these two teeth were found in the lingual mesiodistal diameter (LMD) and the mesial buccolingual diameter (MBL). This result could be explained by the differences in the development of the hypocone and the mesiobuccal stylar shelf.

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The crown dimensions of the dp4 and the M1 on the mandible in Tupaia glis were measured. The dp4 resembled the M1 in pattern, although they were by no means identical. The dp4 was approximately 60 to 85 % of Ml in size, and it was more compressed in the buccolingual than in the mesiodistal direction. The relative size of the talonid was larger for the dp4 than for the Ml. This result may be correlated with an occlusal function.

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The inhibitory effects of electrical stimulation of large myelinated afferents on spinal dorsal horn neurons were investigated. In rats anesthetized with thiamylal sodium, responses of 153 dorsal horn neurons to noxious heating or innocuous mechanical stimulation (light brushing) of the tail were recorded from the sacral and coccygeal levels of the spinal cord by extracellular microelectrodes. Of these neurons, 45 were low-threshold mechanoreceptive (LTM), 47 were nociceptive-specific (NS), and 61 were wide-dynamic-range (WDR) neurons. In 22.2% of the LTM neurons, responses to innocuous mechanical stimulation were inhibited by electrical stimulation of large myelinated afferents applied to the ipsilateral hindlimb for 5 min. This conditioning stimulation (large myelinated afferent stimulation, LMAS) also inhibited noxious heat responses in 19.2% of the NS neurons. The inhibitory effect of LMAS on WDR neurons was nonselective in that both responses to light brushing and noxious heating were inhibited. Of the WDR neurons, 27.3 % were inhibited by LMAS. These results indicate that inhibition produced by LMAS is exerted on all 3 classes of spinal dorsal horn neurons.

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Sotos syndrome is characterized by accelerated growth, minor craniofacial anomalies, and intellectual deficits. The problems of anesthesia with this syndrome are difficulties of intubation, complications of renal function disturbances and others. We already reported the anesthetic experience with Sotos syndrome. The patient was 2 years and 7 months old male, weighing 11.3 kg. Premedication consisted of atropine 0.2 mg and hydroxydine 10 mg intramusculary. Anesthetic induction was performed using inhalational inductions with N₂O, O₂ and halothane, and performed nasal-endotracheal intubation without a muscle relaxtant. Maintenance of anesthesia was performed with N₂O, O₂ and 0.5-0.75% halothane. The duration of anesthesia, there were no significantly change of blood pressure and pulse rate because of light anesthesia without body movement, and the operation were finished safely. Recovery from anesthesia was smooth, and postoperative condition was uneventful.

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