The objective of this study was to compare the hand disinfectant effects between super hypochlorous water and 7.5% povidone-iodine. Subjects included thirty pediatric dentists. They first watched the educational videotape for hand disinfection. They then pressed their right five fingers on Brain Heart Infusion (BHI) agars. They disinfected their hands under running super hypochlorous water until they considered to be enough clean, removed the excess water using a paper towel and again pressed their fingers on the BHI agars. Furthermore, the individual disinfectant time was measured. The agars were incubated at 37°C for 48 h, the colonies counted and calculated as logarithmic values. The same procedures were performed using 75% povidone-iodine two months later. As results, the following observations were shown. The disinfectant effects of super hypochlorous water were significantly more effective than that of 7.5% povidone-iodine. There was no correlation between disinfectant effects of both disinfectants and the hand disinfecting times.

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Five-week-old male Wistar rats were used to study the effect of dietary therapy with ipriflavone combined with 1α-OH-D₃. Ultrastructural alterations in the metaphysis of debilitated tibia were observed in the growing rats.
I. Light microscopy findings
In the low-calcium diet·standard diet with supplementary ipriflavone and 1α-OH-D₃ group, calcification of the chondral matrix and ossification were active, and the tibia grew normally as in the control group.
II. Scanning electron microscopy findings
In the low-calcium diet·standard diet with supplementary ipriflavone and 1α-OH-D₃ group, dense calcospherites, distinct chondral lacunae, regularly running collagen fibers, and distinct border lines were noted.
III. Transmission electron microscopy findings
In the low-calcium diet·standard diet with supplementary ipriflavone and 1α-OH-D₃ group we found that the osteoblasts were active, the ruffled border of osteoclast was decrease, indicated this osteoclast is inactive.
In conclusion, insufficient calcium intake during the developmental period resulted in debilitated(3etaphysis tibia, whereas dietary therapy using combined ipriflavone and 1α-OH-D₃ promoted recovery.

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Bisphenol-A (BPA) has been shown to be an endocrine disruptor in animals. We have previously demonstrated selective extraction of BPA from dental materials and its detection by gas chromatography-mass spectrometry. In the present study, this same procedure was employed for the detection of BPA in materials routinely used in pediatric dentistry—commercial resin composites, fissure sealants, compomers, and dentin bonding agents. In unpolymerized materials, significant BPA contamination was detected in 2 of 3 resin composites, 2 of 5 fissure sealants, and all bonding agents and intermediate resins tested. Moreover, in most cases, incubation of polymerized materials for 24 h resulted in release of BPA into phosphate-buffered saline. However, the highest level of BPA released (89.5 ng/g polymerized material) was still far less than the reported lowest dose that produces endocrine disruption in experimental animals (2μg/kg/d).

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In order to investigate the effects of desensitization which is induced by the application of a vibration stimulus simulating massage to patients with cerebral palsy (CP) on the lower-jaw-position sensation, we compared the masticatory-muscle sensation of patients with CP with that of healthy adults without functional abnormalities of the jaw and oral cavity who were used as control subjects, using a lower-jaw-position sensation discrimination test. The subjects of the study were eight patients with CP and eight healthy adults as control subjects. The following findings were obtained.
1) When the discrimination ability in healthy adults was compared between before and after the stimulus application, it was significantly higher after the stimulus application when the interincisal distance was smaller (9.5 mm) than that with the reference stick.
2) When the discrimination ability of patients with CP was compared between before and after the stimulus application, it was significantly lower after the stimulus application when the interincisal distance was smaller (9.5 mm) than that with the reference stick.
Thus, results for the patients with CP are contrary to those for healthy adults; this is because of the appearance of the tonic vibration reflex in CP patients, which results in a decrease in the activity of γ-motor neurons. The threshold value of muscle sensation was increased by the application of vibration stimulus. Consequently, the discrimination ability of the patients with CP increased.

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Sophora alopecuroides is widely used in Mongolian traditional medicine. The antimicrobial effects of the methanolic and aqueous extracts of its roots against Streptococcus mutans, Streptococcus sobrinus and Staphylococcus aureus were examined in vitro. Four fractions were obtained from methanol extract and labeled as Fractions-1, 2, 3, and 4. The MIC's and MBC's of the crude extracts of Sophora alopecuroides were determined, and bacterial cell growth curves in the presence of Fractions-1, 3, and 4 were drawn. Among the methanolic extracts, the extracts of Fractions-1, 3, and 4 possessed strong inhibitory effect on the growth of mutans streptococci and S. aureus. Fraction-2 and the aqueous extracts of S. alopecuroides had weak antibacterial activities. Thus, S. alopecuroides would be useful for the suppression of oral pathogens, and has potential for use in the prevention of dental caries and treatment of diseases caused by S. aureus.

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Tooth brushing is accepted as an most effective measure to removal of supragingival plaque. The purpose of this study was to examine the effectiveness of a newly designed toothbrush both in brushing-simulator in vitro and in children. The newly designed toothbrush had an oval head with 8 tufts in 3 rows and cleaned the tooth surfaces of primary molar on the plastic model of the dentition more effectively in a brushing-simulator than the control toothbrush with 17 tufts in 3 rows. A total of 66 children participated the study to examine the effectiveness of the brush. The newly designed brush could remove the plaque more effectively from the primary tooth surfaces, especially upper buccal and lower lingual surfaces, than the control brush did. These results indicate that the newly designed toothbrush can remove supragingival plaque effectively in children.

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The purpose of the present study was to examine the degree of calcification and the elementary compositions of salivary calculi in children, and to compare the results with those from adults. Two salivary calculi from children and two from adults were used. Each was divided into two parts, one part was examined with a scanning electron microscope (SEM) equipped with an energy dispersive X-ray analyzer (EDAX) and another part with a microradiographic contact device. Calcium, phosphorus, sodium, magnesium, copper, chlorine, silicon, and aluminum could be identified in the salivary calculi from the children using the EDAX. With regard to the ratio of calcium to phosphorus in Kα-wave intensities, there were no statistical differences between the salivary calculi from the children and those from adults. The radiopacities of the salivary calculi from a 4-year-old girl, an 8-year-old girl, a 23-year-old woman, and a 46-year-old man corresponded to 39.8, 42.6, 41.8 and 42.5μm in aluminum thickness, respectively. There were no statistical differences among them. The findings suggest that salivary calculi from children are similar to those from adults in elements, Ca/P ratio, and radiopacity.

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We investigated the effects of grape seed proanthocyanidin extract (GSPE), 3 mg added in 100 g standard diet with calcium content 480 mg/100 g, on rat tibia formation following a low-calcium feeding (30% calcium of standard diet), by examining bone density, mineral content, geometric and bone strength. Five-week old male Wistar rats (n=40), were randomly divided into: control (Co), low-calcium diet (LC), low-calcium diet·standard diet (LCS), low-calcium diet·standard diet with supplementary GSPE (LCSG) groups. Rat metaphysis tibia bones were analyzed using three-dimensional peripheral quantitative computed tomography (pQCT), as well as the whole tibia bones for mechanical resistance using a material testing machine. Our findings showed that there were no significant differences in body weight among the 4 groups. While, all bone parameters of LC were significantly lower than Co. Further, trabecular bone density (TrBD), trabecular bone mineral content (TrBMC), cross-sectional moment of inertia to the reference axis y (yCSMI), stress strain index to the reference axis x (xSSI) in LCSG were significantly higher than those in LCS. Furthermore, the stiffness in LCSG and LCS were significantly higher than that in LC. We concluded that a mixture of calcium and GSPE in the diet would have a beneficial effect on bone formation for the treatment of bone debility in rats. Further, an increase bone mass in the metaphysis tibia bone is likely accompanied by an increase of bone strength within the whole tibia bone.

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The effect of fluoride and xylitol on remineralization at the early stage of the enamel caries in primary tooth was studied. The samples were divided into four groups (control, 10% xylitol, 950 ppm NaF and 10% xylitol+950 ppm NaF) and analyzed by the using single thin section method and pH-cycling model in vitro. The remineralizing ratio were control −8.9%, xylitol −0.4%, NaF 8.3% and xylitol+NaF 32.4%, respectively. Xylitol+NaF group particularly showed significantly smaller ΔZ value compared with 0 days (P < 0.05). Therefore we assume that the effect of xylitol and fluoride are additive. We concluded that xylitol and fluoride treatment to the tooth enamel may be an effective caries-preventive measure in both primary and permanent tooth enamel.

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The main objective of this study was to investigate the relationship between a caries activity test (CAT21 Test), and caries status. The subjects of this study were 419 preschool children, of Okayama City, Japan and, of Ulaanbaatar City, Mongolia. In all, subjects were examined for dental caries using a mouth mirror and probe. Then buccal plaque samples were obtained, incubated at 37°C for 48 hours, and scored as per the manufacturer's instructions for the Cariostat method. The following results were obtained:
1. The caries prevalence and mean deft of the two subjects was 55.0% and 3.2 for Japanese, so 92.4% and 6.6 for Mongolians, respectively.
2. Results of the CAT21 Test score distribution are as follows: 14% of the Japanese, 7.6% of the Mongolians had a CAT score of 0 (very low risk), 38% of the Japanese, 12.4% of the Mongolians had a 1.0 (low risk), 16.3% of the Japanese, 17.9% of the Mongolians had a 2.0 (middle risk), 25.5% of the Japanese, 36.6% of the Mongolians had a 3.0 (high risk), and 6.2% of the Japanese, 25.5% of the Mongolians had a 4.0 (very high risk) score.
3. There was a statistically significant difference in the CAT21 Test scores and dental caries indices of Japanese and Mongolian preschool children (ANOVA P < 0.01, P < 0.001).
From these results, it was suggested that the CAT21 Test is useful in clinical application.

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Several types of denture attachments are used in pediatric dentistry, however, it is difficult to obtain optimal retention using conventional clasps in young patients, because of the shape variations of primary and erupting permanent teeth. We tested application of a magnetic attachment for space maintenance with an orthodontic appliance in pediatric patients. Using a mixed dentition model, we examined the attraction force of denture materials with a magnetic attachment under several conditions, including type of anchor tooth, keeper angle for tooth axis, and direction of retraction. The optimal keeper angle for the primary first, second, and permanent first molars of the maxilla and primary first and second molars of the mandible was 10°, whereas 20° is best for the permanent first molars of the mandible. In the maxilla, a denture containing primary first and second molars as anchor teeth had relatively high retention compared to the same with permanent first molars. In clinical cases, dentures with magnetic attachments showed greater attraction force than those with Adams clasps in the maxilla, while in the mandible, retention was not significantly different between the two. These results suggest that a magnetic attachment may be useful for denture appliances in pediatric patients.

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The etiology of dental caries has been suggested to be multifactorial. We conducted a cross-sectional study to investigate the contribution of the risk factors for dental caries, surveying a total of 645 preschool children at medical check-ups. Among 10 factors investigated in this study, salivary flow, amount of Lactobacillus, amount of total Streptococci, amount of mutans streptococci, and daily number of times of sweet soft drinks correlate with the prevalence of dental caries. Multivariate Logistic regression analysis using the five factors that correlated produced only two factors, salivary levels of mutans streptococci and Lactobacillus, which correlated with the prevalence of dental caries. Furthermore, clear dose-response relationships were observed in these two factors. We therefore suggest that cariogenic bacteria are the most important risk factor for dental caries among preschool children in Japan.

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The purpose of the present study was to investigate effects of early treatment of maxillary incisor crowding on anteroposterior skeletal and dental changes. Treatment group comprised 17 patients with maxillary incisor crowding treated with the two bands and four brackets (2×4) mechanotherapy, and with an initial mean age of 8 years and 10 months. Control group consisted of 17 patients with the same type of malocclusion as the treatment group and with an initial mean age of 8 years and 7 months. Lateral cephalograms in the treatment group were obtained at three time periods: T1, at the start of the 2×4 mechanotherapy; T2, at the end of the 2×4 mechanotherapy; T3, at the end of posttreatment observation. In the control group, lateral cephalograms were obtained at two time periods: T1, at the start of observation; T3, at the end of observation. Ten linear and 10 angular measurements were made for each cephalogram and the cephalometric data obtained were analysed statistically.
The significantly large retroclination of the mandibular incisors was found at T1 in both groups compared with Japanese norms, resulting in the obtuseness of the interincisal angle. The resolution of maxillary incisor crowding during T1-T2 produced the retrusive movement of maxillary central incisor tips and the retroclination of mandibular incisors. There were no statistically significant differences for the T1-T3 changes in any linear and angular measurements between both groups. The mandibular incisors were, however, inclined labially during T1-T3 in the treatment group, which were, on the contrary, inclined lingually in the control group. These results suggested that the resolution of maxillary incisor crowding mostly produce the anteroposterior dental effects, and that its effect on the correction of the retroclination of mandibular incisors which was observed at the start of the 2×4 mechanotherapy was not so significant.

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Regular check-ups are important for reducing the risk factors of dental caries. Through regular check-ups, clinicians empirically know that the incidence of the new dental caries was suppressed. However, the effects of the regular check-up system have not been thoroughly evaluated. Our primary concern was to evaluate the efficacy of the regular check-up system with professional preventive care for preventing dental caries. In this study, we evaluated attitudes toward regular check-ups. Five hundred and thirteen patients who visited one dental office in Japan from 1981 to 2000 and who were under 12 on the first visit were examined for dental caries, salivary mutans streptococci, and Lactobacilli to obtain baseline values and the values for the more recent visit analyzed in this study. Salivary mutans streptococci and Lactobacilli were counted using Dentocult SM and Dentocult LB. Most of the risk factors, particularly the salivary levels of the mutans streptococci, were reduced by regular check-ups in this study. There was a greater risk reduction in particular for the salivary levels of mutans streptococci in patients undertaking regular check-ups. Reduced salivary levels of Lactobacilli were also observed. However, the changes between the groups in the attitude toward regular check-ups were not statistically significant. This result indicates that most of the risk factors investigated in this study could be reduced by regular check-ups, particularly the levels of mutans streptococci, which has been suggested to be a strong etiology of dental caries.

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In this study, pulpal blood flow (PBF) of human primary teeth was measured using laser Doppler flowmeter (LDF) and efficacy of opaque rubber dam application was examined. Twenty-two healthy and 3 non-vital upper primary central incisors in 13 children (age: 3 years 11 months-7 years 3 months) were examined. Recordings were made with and without opaque rubber dam application. Electrocardiogram (ECG) of the subjects was simultaneously recorded. Results obtained were as follows: 1) With dam application, pulsatile signals synchronous with ECG were recorded from all the healthy teeth, whereas no pulsatile signals were recognized in non-vital teeth. 2) Without dam application, pulsatile signals synchronous with ECG were recorded from all the healthy teeth and non-vital teeth. 3) The amplitude of blood flow signal was significantly reduced by the opaque dam application. Results indicated that PBF measurement using LDF with dam application in human primary central incisors was applicable for pulp vitality assessment.

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The purpose of this study was to investigate the effect of biting pressure on first and second molar eruption, and to clarify that biting pressure may be one of factors influence to tooth eruption. The subjects were 103 patients, 57 (28 boys and 29 girls) were 5 years old, 46 children (23 boys and 23 girls) were 11 years old. Each patient's biting pressure was measured on the second deciduous molar at 5 years old, and on the first molar at 11 years old. The degree of first maxillary and mandibular molars at 5 years old was measured using lateral cephalometric radiogram analysis, and the degree of second maxillary and mandibular molars at 11 years old. Pearson's correlation coefficients were used to study the relationship between biting pressure and the degree of molar eruption.
At 5 years old, a significant statistical negative correlation was observed between the biting pressure of the second deciduous molars and the degree of first mandibular molar eruption. But no significant statistical correlation was observed between the biting pressure of the second deciduous molars and the degree of first maxillary molar eruption. At 11 years old, a significant statistical negative correlation was observed between the biting pressure of the first molar and the degree of second mandibular molar eruption. But no significant statistical negative correlation was observed between the biting pressure of the first molar and the degree of second maxillary molar eruption. These results suggested that the biting force might promote mandibular posterior molar eruption.

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Secretory immunoglobulin A (S-IgA) plays the major role for protecting mucosal tissue from infection, and its level in saliva is thought to be the indicator of immune function in the oral cavity. In the present study, we measured the levels of S-IgA, cortisol and total protein in whole saliva as well as flow rate in healthy young adults (n = 8) throughout a 24-hr period, and found that salivary S-IgA, cortisol and flow rate fluctuated in a circadian manner with their acrophases (peak time of the rhythms) at 06:50 h, 09:04 h and 19.01 h, respectively (P < 0.05). Mesor (midline estimating statistics of rhythm) of the three rhythms was 0.30 mg/ml for S-IgA, 8.56 ng/ml for cortisol, and 0.47 ml/min for the flow rate. The acrophase of S-IgA rhythm corresponded to the nadir of the flow rate rhythm, indicating that these two rhythms are anti-phase to each other. We suggest that the circadian rhythm of S-IgA is not simply subject to daily fluctuation of the volume of salivary fluid that dilutes S-IgA, but is influenced directly or indirectly by central circadian pacemaker, because the ratio of S-IgA to total protein in the morning is more than 3 times higher than that in the evening. The elevation of S-IgA concentration in saliva from midnight to early morning may indicate compensatory mechanism of oral immune system to the fall of saliva secretion during sleep.

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Roots of human deciduous teeth with apical periodontitis frequently show abnormal resorption as well as cementum deposition, and features that are different from those of physiological root resorption. The aim of this study was to determine the relationship between the appearance of cultured osteoclasts and the condition of dentin slices of human deciduous teeth. Bone marrow obtained from femora of 3- and 4-week-old male C57BL/6 mice was used for cell culture. The cells used in this study were osteoclasts, bone cells and bone marrow cells. Root dentin slices were prepared from human deciduous teeth with apical periodontitis (group 1) and from sound deciduous teeth (group 2, control group). The dentin surfaces were polished with grindstones. Cell suspension in α-MEM supplemented with 10% fetal bovine serum was seeded on the dentin slices and incubated for 96 hours at 37°C under 5% CO₂ in air. After incubation, specimens were removed and fixed with glutaraldehyde and paraformaldehyde, and then tartrate-resistant acid phosphatase (TRAP) activity, which is considered to be specific to osteoclasts and odontoclasts, was detected. The number of TRAP-positive cells on the dentin were calculated by light microscopic observation. Specimens were then prepared and observed under a scanning electron microscope (SEM). TRAP-positive cells, visible as small red dots, were observed on dentin slices of both groups (n = 50: each group). The densities of TRAP-positive cells in group 1 and group 2 were 2.98 ± 2.57 cells/mm² and 2.90 ± 2.22 cells/mm², respectively. The difference between densities of TRAP-positive cells in group 1 and group 2 was not significant by the Mann-Whitney U-test (P > 0.05). Shallow resorbed lacunae were observed on the specimens by scanning electron microscopy. It was shown that root dentin with apical periodontitis was resorbed by clastic cells such as cultured osteoclasts, suggesting that cell growth on dentin is not affected by apical periodontitis.

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Cell chemotaxis plays a role in many cellular or individual actions suited to accomplishing a variety of purposes. These actions include activities of bacteria and Protista, cellular slime molds' migration to food, starvation-induced aggregation of cellular slime molds and mobilization of immunocytes to infectious or inflammatory sites in higher order animals. Macrophages, neutrophils, C3H10T1/2 clone 8 (10T1/2 (SIGMA, USA)) cells, etc. are chemotactic cells. Macrophages and neutrophils are terminally differentiated cells, while 10T1/2 cells are undifferentiated mesenchymal cells. However, currently there is almost no research in which chemotaxis of terminally differentiated cells and undifferentiated mesenchymal cells are comparatively evaluated. Therefore, in this article, the effects of phospholipase C (SIGMA, USA) or phospholipase D (SIGMA, USA) on chemotaxis were evaluated using these 3 types of cells in different differentiation states. The chemotaxis of each cell was evaluated using D609 (SIGMA, USA) and ET-18-OCH₃ (SIGMA, USA)(which are phospholipase C inhibitors), and suramin (SIGMA, USA) and D-erythro-Sphingosine (SIGMA, USA)(which are phospholipase D inhibitors). As chemotactic factors, ZAS was used for macrophages and neutrophils, and platelet-derived growth factor (PDGF) was used for 10T1/2 cells. The chemotaxis of each cell was assessed using 96-hole chemotaxis chambers. Firstly, chemotactic factors were added only to the lower chambers, and chemotaxis was then measured. In macrophages, D609, ET-18-OCH₃, suramin and D-erythro-Sphingosine significantly inhibited chemotactic activity. In neutrophils and 10T1/2 cells, D609 and ET-18-OCH₃ significantly inhibited chemotactic activity. To study these inhibiting mechanisms, further evaluation was performed. ET-18-OCH₃ significantly and dose-dependently inhibited random migration when chemotactic factors were added to both upper and lower chambers. However, ET-18-OCH₃ did not significantly affect chemokinesis where no chemotactic factor had been added. Secondly, in 10T1/2 cells, D609 significantly reduced random migration and chemokinetics, but ET-18-OCH₃ did not significantly change random migration and chemokinesis, even though it slightly reduced them.

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A rare case is presented in which a congenitally missing primary canine, an abnormally formed primary first molar and an impacted supernumerary premolar were found in the same lower left quadrant. The patient was a Japanese girl aged 2 years and 10 months. After 4 years of observation, when the girl was 6 years 2 months old, the abnormal first primary molar and the impacted supernumerary tooth were extracted to avoid disturbance of the developing lower first premolar. The extracted teeth were examined microscopically. The first primary molar seemed to be a fusion of a normal first primary molar with a small coronal tooth. Thus the supernumerary premolar seemed to be a successor of the coronal tooth. When the patient was 8 years 1 month old, the lower left permanent canine began to erupt; its shape was normal.

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Gingival fibromatosis is a rare clinical finding of non-inflammatory gingival overgrowth. Here we present 2 cases of children with gingival fibromatosis and provide a longitudinal analysis of the correlation between the presence of periodontal bacteria and clinical condition. The first case, a boy treated from age 2 to 6, showed periodontitis in the lower anterior region, which recovered to a good periodontal condition by a professional therapeutic approach. The second case is a girl, treated for 2 years from age 10, who presented with extremely enlarged gingiva and severe gingivitis, and a gingivectomy was carried out to eliminate the dental plaque accumulation. In both cases, periodontal bacteria were assessed periodically using PCR (Polymerase Chain Reaction) method, and the results compared with the clinical conditions. In both cases, increased numbers of periodontal bacteria were detected during the bad gingival condition period. In addition, Prevotella nigrescens and Prevotella intermedia were especially detected. Clinical condition seems to be influenced by the number of the periodontal bacteria present, which indicates that an effective monitoring of such bacteria would be beneficial for not only evaluating the current periodontal condition, but also for making an appropriate prognosis of a lesion.

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