Tooth brushing movements and brushing forces are dependent on sensations felt in the hand and arm that hold the brush and feeling in the periodontal membrane and gingiva. Therefore, it is often difficult to correct poor brushing habits that a person has acquired simply by instructing him using a model of the dentition. We developed a computer program that automatically measures and analyzes brushing forces, the number of brushing strokes, distortion in the toothbrush, action potentials in the hand and arm muscles, motion ranges of the wrist and forearm, and forces gripping the toothbrush while the subject brushes with various methods (scrubbing, Bass, rolling and modified Stillman). Shika Igaku (J Osaka Odontol Soc) 2003 Jun; 66(2): 151-166.

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We did an in vitro study using the co-culture technique on the influence of periodontal dressing materials on the formation of tubule-like structures by human umbilical vein endothelial cells and human diploid fibroblasts of dermal origin. The rate of growth in length and in area were measured for the tubule-like structures using an Angiogenesis Image Analyzer (Kurabo Industries Ltd., Osaka, Japan). Cell viability was examined by 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT). Of the three materials tested, Coe-Pak, which is eugenol-free, had the largest values for both tests. Formation of the tubule-like structures occurred in the range of 0.078-5.000 mg/mL. In contrast, Surgicalpack N, which was in the eugenol group, had the lowest, and Peripac was in between the other two. Results for the cell viability test were similar to those for the formation of tubule-like structures. We found that eugenol-type periodontal dressing materials had a greater inhibitory effect than the eugenol-free type. This co-culture technique has not previously been used for this type of study. Further studies of this type should be productive. Shika Igaku (J Osaka Odontol Soc) 2003 Jun; 66(2): 167-175.

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Malocclusions associated with a deep overbite are difficult to treat. We investigated various factors associated with deepbite malocclusion. Standardized lateral cephalograms were taken on 60 adult females who had deep overbite with their teeth in occlusion. Vertical, horizontal and angular measurements were recorded. We then determined the degree of correlation between the overbite and 55 variables. Previous reports supported the findings of our study that there is a strong correlation between the vertical position of the maxillary incisors, the interincisor angle, and the overbite. we also found that the curve of Spee must be taken into consideration when correcting the interincisor angle because there is a correlation between the interincisor angle. Our results show that orthodontists must first reduce the overbite in the cuspids before controlling the deep overbite in the incisors.

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We investigated the craniofacial growth and development of 120 Japanese elementary school children (60 males and 60 females). The subjects were divided into six groups based on their skeletal facial patterns (Class I, Class II or Class III) and gender. We did statistical calculations on the angular and linear measurements using tracings of head radiographs.
We found that growth at the anterior cranial base was lowest in the Class III 4th graders. However the amount of the anterior growth at the maxillofacial complex in the Class II group was less than in the other groups. The Class Ⅲ group showed more clockwise rotation than the other groups. Increases in the inclination of the upper and lower incisors were seen in all groups. Boys showed more growth change in the craniofacial complex than did the girls.Shika Igaku(J Osaka Odontol Soc) 2003 Jun; 66(2): 183-197.

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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 between initial and post-splint cephalograms 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 Steiner 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 eminentia. 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.Shika Igaku(J Osaka Odontol Soc) 2003 Jun; 66(2): 198-204.

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We examined the tissue compatibility, sealing ability and interface between a newly-developed resin-based reverse filling material and the root canal wall using scanning electron microscopy (SEM). The filling material was composed of 4-META/MMA-TBB and zirconium oxide (RO). The sealing ability of RO was better than that of the control material (amalgam) when evaluated by apical dye leakage. SEM observation of the interface between RO and the canal wall showed resin tags and hybridized dentin. Histopathological examination (H-E stain) of rat subcutaneous tissues revealed that inflammatory responses were less than with the control material. Likewise, infiltration of macrophages seen by immunohistochemical staining was also less than in the control. We found that RO was less irritating to the periapical tissue than was the control material. These results indicate that the newly developed reverse filling material may be useful for endodontic treatment.

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We evaluated the tissue compatibility of two newly-developed root canal sealers, one composed of 4-META/MMA-TBB resin and zirconium oxide (ZrC), and the other of 4-META/MMA-TBB resin, barium sulfate and bismuth subcar-bonate (A 4). We examined the responses of rat dorsal subcutaneous and periapical tissues to these materials. In order to examine the response in subcutaneous tissue, sections were stained with H-E for histopathological observation and with immunohistochemical stain for observation of macrophages. Serial sections were stained with H-E for histopathological observation of the periapical tissue response. The newly-developed sealers caused less subcutaneous inflammation than zinc oxide eugenol cement (the control). There was significantly less infiltration of macrophages with ZrC and A 4 compared with the control material at 4 weeks. ZrC and A 4 caused less tissue irritation in the periapical tissues than did the control material. These results indicate that both of the newly-developed root canal sealers may be useful for endodontic treatment. The one with ZrC showed especially promising results.

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We analyzed metallic artifacts in magnetic resonance imaging (MRI) caused by 14 dental crowns made of NiCr alloy. Three sequences of MRI (FSE-3 D, FSE-2 D and SE-2 D) were taken of anterior and posteriot cast crowns combined in various arrangements. We observed the shape and the 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.

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