We studied to determine the role of surface enamel during early carious lesion formation in deciduous teeth. Sixteen enamel specimens 3 mm in diameter were prepared from deciduous and permanent teeth using a hollow core drill. Surfaces of the specimens were then highly polished. Half were used controls and the other half for the study of early carious lesions. The lesion was produced by immersing the tooth in a demineralizing solution (pH 5.0) of 0.1 M lactic acid, 0.2% carbopol and 50% saturated hydroxyapatite for 4 or 24 hours. The surface structure of the subsurface lesion was observed by atomic force microscope (AFM) and a longitudinal section of the lesion was observed by SEM. The mineral profile of the lesion was analyzed using translucent microradiograph (TMR) technique. The parameters for the mineral profile were surface thickness, lesion depth and mineral loss.
Based on the results of AFM and SEM images, and the mineral profiles, we concluded that both play active roles in controlling the degree of early carious lesion formation in deciduous teeth.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 261-269.

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We determined a method of evaluating the oral health status of various age groups in Japan. We attempted to analyze the relation between dental caries (DMFT) and age in two age groups (5 to 15 years and over 20 years). The basic data were obtained from the Report on the Survey of Dental Diseases for the years 1957 to 1999. For the 5 to 15 year age group the slope of the linear regression line increased during 24 years between 1957 and 1981, but then decreased for the next 18 years from 1981 to 1999. These results indicated caries increased during the first period but then decreased after that for the 5 to 15 year age group. For those over 20 years, the slope and y-intercept of the linear line increased from 1957 to 1999. The slope and Y-intercept of the linear regression line relating DMFT and age could be used to evaluate changes in caries experience in an age group. We concluded that the oral health status of a group could be evaluated by the slope and Y-intercept data of the linear regression line relating DMFT and age.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 270-278.

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We evaluated use of the oral age index to determine the status of oral health in the community. We compared the actual age and oral age of residents in each community. The oral age index is a total assessment of a person's oral health based on the number of sound teeth and the health of the periodontal tissues. An oral age younger than the actual age is desirable. We surveyed 7,456 people in 24 districts of Osaka City and 31 towns in Osaka Prefecture. We concluded that the oral age index is appropriate for evaluating a community's oral health status and for accurately assessing differences in oral health status among communities. We also developed a map showing the status of each community's oral health so as to better understand their needs.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 279-288.

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We developed a method of caries risk assessment for the permanent teeth of school children to be used in a program of caries reduction. We employed two types of caries activity tests (Dentocult-SM and Cariostat) and various caries indices (caries incidence rate, dft index and DMFT index) to assess the caries risk in school children during regular oral check ups. We studied 921 children (543 boys and 378 girls) in the first through sixth grades of elementary school over a period of six years from 1997 to 2002. The results indicated that screening with the SM score and the number of df teeth during the first three years of elementary school could predict caries risk in the permanent teeth one year later. Furthermore, this screening indicated sensitivity, and negative predictive value were greater than 90%.
We concluded that the caries activity test is suitable for assessing caries risk in elementary school children. Our method for caries risk assessment may contribute to oral health promotion and dental caries prevention in elementary school children.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 289-301.

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We studied the detection and quantification of enamel erosion using digital imaging fiber-optic trans-illumination (DIFOTI^TM). We prepared three sample teeth from extracted human mandibular incisors that had no white-spot lesions and were caries free based on visual examination. A window 3 mm in diameter was made on the buccal surface of each sample tooth with nail varnish and the sample was immersed in 0.1 M HCI solution for 10 minutes at room temperature to produce enamel erosion. DIFOTI^TM was employed to observe and analyze the enamel erosion. The treatment was repeated 6 times for each tooth.
The results indicated that by using differences in the contrast level observed in the DIFOTI^TM image, it was possible to detect erosion on the enamel surface. The level of enamel erosion created by the acid-immersion time could be evaluated by differences in the mean percent contrast values of the DIFOTI^TM images between the sound and eroded enamel. We concluded that DIFOTI^TM can be used to detect and quantitatively evaluate enamel erosion that has occurred on the tooth surface.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 302-307.

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There has been much research on how people avaluate an aesthetic profile. Several factors are involved. We gave questionnaires orthodontic patients, orthodontists and people representing the general public. The general public gave the highest evaluation to normal occlusion, followed by Angle class II-2, Angle class II-1, Angle class III and bimaxillary protrusion in that order. There were significant differences at p<0.01 between normal occlusion and class II-2, and between class II-1 and class III. Among orthodontists, the order of evaluation was same as for the general public. There were significant differences at p<0.01 between normal occlusion and class II-2, between class II-2 and class II-1, and between class II-1 and class III. The was a significant difference at p<0.05 between class III and bimaxillary protrusion. Among orthodontic patients, the order of the evaluation was the same as for the general public. There were significant differences at p<0.01 between class II-2 and class II-1, between class II-1 and class III, and between class III and bimaxillary protrusion. The order of evaluation was similar for orthodontic patients and the general public, but there were considerable differences in the order for orthodontists. Among orthodontic patients, there was a strong tendency to regard protrusion of the lips as very unesthetic.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 308-318.

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Orthodontists consider improvement of occlusion as the primary goal of orthodontic treatment. However, their patients put considerable emphasis on the improvement of esthetics. We gave questionnaires on the esthetic profile to patients receiving orthodontic treatment for maxillary protrusion and for mandibular protrusion. We found that for both groups the profile with normal occlusion was the most esthetic. This was followed by Angle class II-2, Angle class II-1, Angle class III, and Angle class I with bimaxillary protrusion in that order. The maxillary protrusion patients who had not yet received treatment considered Angle class II-1 and Angle class I with bimaxillary protrusion as being particularly unesthetic. This suggests the maxillary protrusion patients particularly dislike projection of the lips. The mandibular protrusion patients who had not yet received treatment considered the Angle class III profile as particularly unesthetic. Both the maxillary protrusion patients and the mandibular protrusion patients seemed to be very conscious of their profile. These results suggest that orthodontists should place considerable emphasis on communication with their patients when planning orthodontic treatment and setting up treatment goals.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 314-318.

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We investigated the effect of regenerated tissue had on tooth movement following guided tissue regeneration. The procedure was done on the maxillary right first molar in 60 Wistar rats. All rats were divided into three groups. The buccal bone was reduced apical to the cementoenamel junction in two of the groups. In the first (experimental) group, Gore-Tex GTR membrane was adapted and sealed to the root surface before suturing the flaps. No membrane was placed in the second (sham operation) group. No surgical procedure was done in the third (control) group. The membrane was removed after four weeks and orthodontic force was applied. The amount of tooth movement was measured after two weeks, at which time the orthodontic force was removed. The movement was measured again two weeks later.
The amount was greatest in the sham operation group, followed by the experimental group and the control group, in that order. After two weeks of retention, the amount of relapse in the experimental group was almost the same as that in the controls. These results suggest that orthodontic treatment is possible following guided tissue regeneration.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 319-324.

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Orthodontists often measure cephalograms with rulers or scan them into computers during treatment planning. We examined the accuracy of several measurement methods. Using cephalograms of adult males with normal occlusion. Three methods were considered: pencil traces measured by rulers, pencil traces input to a computer using a scanner, and cephalograms directly input to a computer. We calculated significance at the 95% confidence level, and applied the F-test for variance.
The 95% confidence level measurements were greatest for the pencil traces (1.0 mm and 0.5 degrees). These values were smallest for the group where the cephalograms were directly input to the computer (about 0.2 mm and 0.2 degrees). There was a significant difference at the 1% confidence level for differences between the group where measurements were by direct scanning into the computer when compared with the other two groups. We concluded that in order to increase accuracy, it is necessary to evaluate the cephalograms by direct scanning into a computer.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 325-330.

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We investigated the magnitude of occlusal pressure and stress distribution on the condylar head of a dry human skull when an experimental masseter muscle was activated at different clenching positions. Occlusal pressure increased as the occlusal support was moved distally. Clenching on the first premolar produced the strongest pressure on the head of the condyle on the nonworking side. Decreased pressure was observed on the front, top, lateral side and medial side of the head, in that order. Clenching from the region of the second premolar to the third molar produced the largest pressure on the top and front of the head. Clenching on the first premolar produced little pressure on the frontal, lateral and medial regions of the head of the condyle on the working side. Pressure on the front of the head of the working side condyle decreased with occlusion on the posterior teeth. The head tended to float in the mandibular fossa with occlusion on the second and third molars. We found that pressure on the temporomandibular joints changed with the position of the occlusal force.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 331-338.

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We evaluated the effect of various periodontal treatments, which included scaling alone, scaling before and after treatment with YAG and CO₂lasers, root planing alone and root planing before and after treatment using the two lasers.
Evaluation was carried out using an X-ray microanalyzer (XMA), by scanning electron microscopy (SEM), by X-ray photoelectron spectroscopy (ESCA), and by measuring the contact angles in vitro. There was little difference whether irradiation was done before or after treatment, regardless of the method of evaluation.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 339-349.

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Analysis of malodorous components of the breath requires a large experimental facility. We recently developed breath detection equipment that had ammonia, not methyl mercaptan, as its target. We found that the amount of ammonia in a healthy subject was less than 16 ppm. There was a significant positive correlation between the amount of ammonia measured by the breath inspection equipment and that of methyl mercaptan detected by gas chromatography in 12 patients with periodontal disease who had halitosis. Also, there was a positive correlation between the amount of ammonia, clinical findings, and the bacteria count indicated by a phase contrast microscope. We found that the amount of ammonia decreased after initial preparation for periodontal therapy.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 350-360.

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We analyzed the circumference of the glenoid fossa in the temporomandibular join (TMJ) during childhood using Computed tomography (CT) data obtained from selected patients who were imaged for other diagnostic purposes over the maxilla and/or mandible. The data included 72 joints in 36 patients (18 males and 18 females) between the ages of 7 and 12 years. None of the patients had growth abnormalities, such as facial growth disturbance. CT three-dimensional (3 D) images were constructed by the volume rendering technique. Five subjects were used to analyze six parameters of the glenoid fossa: vertical dimension, antero-posterior dimension, medio-lateral dimension, location in the axial plane, and angle of the glenoid fossa. Measured values were calculated in the 3 D images where the axial, coronal and saggital aspects could be observed. Spearman's correlation coefficient was used for statistical analysis. Of these values, the medio-lateral value correlated best with the circumference. These results suggest that the entire TMJ structure develops in the medio-lateral dimension during childhood.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 361-367.

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We investigated the formation stage of the microvascular architecture (MA) after transplantating tumor tissues. We transplanted a human tongue cancer cell line (Tca 8113) subcutaneously into the dorso-lumbar region of female nude mice. The proliferated tumor tissue was extracted and transplanted into another nude mouse. At 10 and 20 days after transplantation, corrosion cast specimens were prepared to study the MA of the tumor tissue (TT) using a scanning electron microscope. At 10 days, the blood vessels were meandering, and their diameters were markedly decreased. Leakage of acrylic resin was also observed. At 20 days, the capillary network was seen in the outermost layer of the TT. In addition, many short rod-like processes were observed on the surface of the capillary network. These processes were thought to represent the initial stage of tumor angiogenesis. We speculated that the new capillary network supplying cancer cells was formed outside the pre-existing capillary network. However, inside of the network, in the deep layer of the cancer, few capillaries were observed, and the area was filled almost completely with TT.
Based on these results and those of our predecessors, we concluded that the formation stage of MA occurred between 15 and 18 days after transplantation.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 368-376.

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Since 1972, we have bred naturally occurring gingivitis rats (ODUS/Odu) in our laboratory. They were originally derived from the Wistar-Kyoto strain, and are now in the 84 th generation. The animals were given a commercial powdered diet and tap water ad libitum from five weeks after birth. They had heavy plaque formation on the mandibular incisors and developed both periodontal pockets and gingivitis. We investigated plaque formation susceptibility in these rats using ODUS/Odu and ACl/NJcl, both of which were fed a commercial powdered diet. We obtained first filial generation (F₁) rats, second filial (F₂) rats and backcross rats, and judged their plaque index by the method of Ito et al.
The F₁ rats did not exhibit plaque formation throughout the experimental period. Plaque formation was seen in 50% of the F₂ rats, and 87.4% of the backcross rats. These results suggested that plaque formation susceptibility may be regulated by three autosomal recessive genes.Shika Igaku(J Osaka Odontol Soc) 2003 Dec; 66(4): 377-383.

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Prevotella nigrescens, a Gram-negative black-pigmented anaerobic rod, is frequently isolated from periodontitis and periapical lesions. We isolated an exopolysaccharide (EPS)-producing P. nigrescens, strain 22, from a chronic periodontitis lesion. In this study, we characterized the chemical structure of the purified EPS from strain 22, and studied the biological effects of EPS on abscess formation in mice and on the phagocytosis of peripheral blood polymorphonuclear leukocytes using strain 22, heat-killed strain 22, and an EPS-non-producing mutant, strain 328. EPS exhibited anti-phagocytic activity in vitro, and strain 22 and its heat-killed counterpart induced large abscesses in mice. However, strain 328 did not induce abscesses. These results suggest that one of the functions of EPS produced by strain 22 is to protect the bacteria from the phagocytotic system in order to ensure a longer survival of the organism in the host.

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It has been reported that more than 90% of diabetes mellitus (DM) patients in Japan suffer from the type II variety of the disease. Many studies have been conducted on the relationship between DM and periodontal disease. However, only a very few have focused on the morphological investigation of the epithelium in a type II diabetic rat model. We investigated and compared morphological changes in the gingival epithelium of both normal and type II diabetic rats. We found that development of the epithelium peg was very poor in the type n rats. We concluded that the epithelium of diabetic rats might be very weak to external stimuli.

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Haloperidol is one of the most widely prescribed of conventional antipsychotic drugs. We compared drug concentrations in the saliva, blood and brain, after intravenous administration (0.25 mg/kg) in rats. We also investigated immunohistochemical localizations of the haloperidol. There was a significant correlation between the level of salivary haloperidol in the blood and that in the brain (p<0.01). The correlation coefficient between levels in the saliva and the brain (r=0.56-0.71) was greater than that between the blood and the brain (r=0.37-0.59). The striated duct within the gland was strongly positive for haloperidol. This study supports the concept that salivary haloperidol concentration may be used effectively for therapeutic drug monitoring.

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We investigated the influence of psychological stress on the levels of salivary amylase and cortisol. The amylase level was increased by viewing stressful videos. The cortisol level was increased three minutes later than that of the amylase. Although the amylase level was decreased when the subject watched a soothing video, the cortisol level remained the same. Those results show that the salivary amylase level was increased more significantly and reacted more rapidly to psychological stress than did the cortisol level, suggesting that it is a better index of stress. In addition, the amylase level might be used as an index of comfort.

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We investigated the relation between the length a dental implant is embedded in bone and its mobility in two different models, one with cortical anchorage and one without. The implants were made of brass cylinders 4 mm in diameter which were embedded 7, 9, 11, 13, 15 and 17mm into a resin model of bone. We measured the implant movement (IM) score horizontally with an implant movement checker. We found that the cortical bone was very important for implant stability and that increasing the length the implant was embedded in the bone did not proportionately reduce mobility.

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