Skeletal malocclusion with anterior open bite is much more difficult to correct with orthodontics than anteroposterior malocclusion. Anterior open bite induced by skeletal factors is primarily caused by congenital defects or internal diseases. It tends to worsen over time and is associated with persistent abnormality of the craniofacial complex.
We attempted to clarify the relationship between congenital myopathy (the deficiency of type II fibers with minicore) and skeletal Class Ⅲ patients with anterior open bite, as well as, the relationship between vertical facial proportions and over bite.
We found that anterior facial height is significantly greater in this myopathy patient than in skeletal Class III cases with anterior open bite (the control group). In addition, the mandibular body showed more severe clockwise rotation in this myopathy patient than in the control group. Also, descent of the palate in the posterior region was significantly greater in this myopathy patient. We also found that the depth of the palate and the ratio between the depth of the palate and the width of the maxillary dentitions were significantly greater in this myopathy patient than in the control.
These results seem to imply that overbite might be affected by morphological and spatial changes in the palate caused by a deficiency in muscle activity. The morphology and the depth of the palate seemed to be very useful in assessing relations between the vertical proportions of the dentofacial complex and the overbite.Shika Igaku(J Osaka Odontol Soc) 2003 Jun; 66(3): 211-219.

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Erroneous administration of even a small dose of local anesthetic into the carotid artery may induce generalized seizures resulting from acute lidocaine intoxication. We infused lidocaine continuously with or without epinephrine into the carotid artery or femoral vein of rabbits to compare the lowest cumulative dose that would induce seizures, and recorded blood lidocaine levels and cerebral hemodynamics at the onset of seizures for the two routes of administration. Four groups of rabbits under ventilation received lidocaine with or without epinephrine via the cervical artery or femoral vein, and their electroencephalogram, mean arterial pressure, regional cerebral blood flow, and rectal temperature were monitored. Cumulative dose and the plasma level of lidocaine at the onset of seizures were compared for the four groups.
In rabbits receiving lidocaine alone, plasma lidocaine level at seizure onset was lower with administration via the carotid artery than via the femoral vein, although there was no difference in the cumulative dose at onset. In rabbits receiving lidocaine with epinephrine, the epinephrine increased the lowest intracarotid lidocaine dose that induced seizures, but did not affect plasma lidocaine level at onset for either route of administration.Shika Igaku(J Osaka Odontol Soc) 2003 Sep; 66(3): 220-226.

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Standardization of photographic technique and color assessment are necessary in order to utilize image information as data. We developed a standard photographic system incorporating these requirements. Using this system, we examined color differences between areas of free and attached gingiva in healthy individuals. We found a strong correlation between the two types of gingiva. We also compared healthy gingiva with unhealthy gingiva produced by experimental procedures. We found that the blue and green ranges in RGB color were consistent regardless of individual differences in the gingiva.Shika Igaku(J Osaka Odontol Soc) 2003 Sep; 66(3): 227-235.

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We attempted to develop indices for stress reactions in young orthodontic patients.
Two hundred seven orthodontic patients (37 male junior high school students, 77 female junior high school students, 33 male high school students, and 60 female high school students) were asked to answer questionnaires regarding their reaction to stress during treatment.
The results were analyzed statistically by factor analysis. Fifty two psychological stress reactions were analyzed. These included 13 emotional reactions, 30 cognitional reactions and 9 physiological reactions.
We developed indices for stress reactions in young orthodontic patients where severity was rated on a scale from 0 to 3. We feel it important that dentists consider the psychological stress of patients their in clinical orthodontic practice.Shika Igaku(J Osaka Odontol Soc) 2003 Sep; 66(3): 236-240.

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Among soft tissue analysis methods used in orthodontic diagnosis, the one invented by Yamawaki is of particular interest. Although this analysis predicts the soft tissue A-Po to FH angle from the hard tissue A-Po to FH angle, the relationship between these angles does not apply for high or low angle patients. We studied the relationship between these two angles in 50 high angle patients and 50 low angle patients. The correlation between the hard tissue A-Po to FH angle and the soft tissue A-Po to FH angle was analyzed for each group using linear regression. We required a significant difference at the p=0.01 level between the hard tissue A-Po to FH angle and the soft tissue A-Po to FH angle for inclusion in the analysis.
For high angle patients post-treatment, the correlation equation was y=0.87x+8.9, while for low angle patients it was y=0.89x+8.21. The change in the soft tissue A-Po to FH angle in both groups was smaller than that for normal orthodontic patients. Our equations provide the relationship between the hard tissue A-Po to FH angle and the soft tissue A-Po to FH angle for high and low angle patients.Shika Igaku(J Osaka Odontol Soc) 2003 Sep; 66(3): 241-246.

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We analyzed metallic artifacts in magnetic resonance images (MRI) caused by 14 dental crowns made of NiCr alloy Three MRI sequences (FSE-3 D, FSE-2 D and SE-2 D) were taken of anterior and posterior cast crowns combined in various arrangements We observed the shape and volume of the resulting metallic artifacts using multi-planer and three-dimensional reconstructions from the slice data
The metallic artifacts were divided into three signal intensities high, intermediate and low. The shape of the crown, which was in the center of the artifact, could be detected in the area of low signal intensity An area of high signal intensity existed only in the frequency direction of the metallic crowns in the slice data An area of intermediate signal intensity extended widely vertically and horizontally The high signal intensity area increased in volume as the number of crowns increased.Shika Igaku(J Osaka Odontol Soc) 2003 Sep; 66(3): 247-254.

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We investigated the magnitude of occlusal pressure and stress distribution on the condylar head produced by experimental occlusal forces imparted at different positions of occlusal support using a dry human skull Occlusal pressure increased as the occlusal support was moved distally Pressure on the frontal area of the head of the condyle on the nonworking side decreased as the posterior occlusal support increased, while pressure on the top of the condyle increased Little pressure was measured on the frontal and lateral areas of the head of the condyle on the working side when occlusal support was on the first premolar Pressure on the frontal and lateral areas of the nonworking condyle head was decreased when occlusal support was on the posterior teeth, and the working side condyle head floated in the maxillary fossa when occlusal support was on the second and third molars Pressure on the condyle head changed position and magnitude depending on the occlusal support Special care should be taken when changing the antero-postenor positions of molars during orthodontic treatment

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Many orthodontic patients have displaced disks and unstable mandibular positions If orthodontic treatment is done without stabilizing the mandible, the treatment result will not be satisfactory Current orthodontic philosophy advocates that diagnosis should be made with the patient's mandible in centric relation stabilized by a full-coverage gnathological repositioning splint if the patient's mandible is unstable We examined cephalometrically the effect the gnathological splint had on patients Lateral cephalograms were taken of 31 female patients before and after splint therapy Measurements of cephalograms were analysed by the Roth-Jarabak, Powell, Ricketts and Steiner methods The paired t-test was used to assess whether measurements of post-splint cephalograms were significantly defferent from those of the initial cephalograms Statistically significant differences were found betweeen initial and post-splint cepahlograms for 8 of the 14 items in the Roth-Jarabak analysis, 2 of the 4 items in the Powell analysis, 8 of the 12 items in the Ricketts analysis, and 11 of the 16 items in the Stemer analysis Morphological changes between the initial and post-splint cephalograms showed that the body of the mandible rotated backward and the condyles were seated in the most superior and anterior position against the posterior slope of the emmentia Labial tipping movement of the maxillary incisors and mesial bodily movement of maxillary molars were observed Orthopedic forward movement of the maxilla caused by force from the splint was not seen

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We investigated the relationship between dental treatment stress and function of the autonomic nervous system during dental anesthesia and impression taking The procedures were administered to five healthy volunteers, once each week for a total of three times We analyzed the frequency of the R-R interval of the electrocardiogram, and calculated the integrated power values based on the obtained power spectrum for the respective components in the low frequency bands (LF 0 04-0 15 Hz) and high frequency bands (HF 015-0 40 Hz) The ratio of LF to HF was used as an index of sympathetic nervous system function This ratio decreased with repeated impression taking, but not with repetition of dental anesthesia We found that different procedures produced different stresses

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