We investigated the all members (4,298 people, of which 4,160 were dentists) concerning recognition of the specialist system of pediatric dentistry authorized by corporate limited liability with in the Japanese Association of Pediatric Dentistry (Hereafter, the specialist). The questionnaire was sent to to 4,298 members (the total of those on answered was 1,140 people, include in 1,129 dentists). We examined the questionnaire of 1,129 dentists who answered and the following was obtained.
1. About 29.1% of the members who have the qualified as for pediatric dentists au thorized by Association of Japanese Pediatric Dentistry hoped to obtain specialist qualification immediately.
2. 80.6% of the members who were not qualified as pediatric dentists answered that they wanted to take an examination for qualified as a specialist as soon as they are qualified to take it. However, numerous members hoped that the examination of specialists would be strictly carried out strictly.
3. 22.6% of the members thought that the qualifications for pediatric dentists authorized by the Association of Japanese Pediatric dentistry should be abolished after putting the specialists system effect.
4. 14.5% who have are qualifico as of pediatric dentists authorized by the Association for Japanese Pediatric Dentistry do no want to acquire the specialist qualification, but they wanted to renew their qualifications.
5. As the dentists got older, the ratio of child patients (under 18 years old) tended to decrease. However, about one-fourth, (112 members about 10% of all) of dentists who are 50-69 years old (347members) Accounted forit occupied 34.7% of all treated exceeded 90% children patients Thus, it appeared to be a tendency of bipolarization.
The result of this questionnaire suggested that the dentists who want to be qualified specialists will be able to become excellent dentists for children, and obtain the information needed for running an organization easily, while they will have to give some information about their medical environment.
We then asked permission from the Ministry of Health, Labour and Welfare to advert ise as specialists. They keenly feel the importance of the self-responsibility.

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We compared the denaturation image of the enamel surface by observation of the SEM observation in with black ink material for the laser reaction and in with substitution use of HY Cement.
The summary of the result is as follows.
1. Under all the conditions of irradiation, use of black ink use and use of the substitution HY Cement were clearly different according to the denaturation condition of enamel surface.
2. With the use of black ink material use, the structure like lave which causes the efficiency of the acid resistant activity of the enamel and forming of cracks were observed with throughout.
3. With substitution of Nd: YAG laser adsorption instead of HY Cement which was originally used for lining and temporary sealing, obviously could not give the same range of denaturation as black ink material.

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We investigated the overall status of oral health among new patients visiting our pediatric dental hospital from 1995 to 2004 to enable us to reconsider a course of medical education and training for students and post graduate dentists. Subjects and Methods:
The subjects of this study were 5,291 new patients who visited the department of pediatric dentistry department at Kanagawa Dental College Hospital from 1995 to 2004. For each new patient, we recorded the age, address, chief complaint, and other information using medical examination interview forms. Our results provide a basis for discussing demographic changes, the present Japanese birthrate, the number of dental health care facilities within the city of Yokosuka, and other important topics. Results and discussion:
1) There had been an annual increase in the number of new patients registered in the Pediatric Dentistry department in the hospital of Kanagawa Dental College from 2001 to 2004.
2) The number of children aged 2 or 3 among the new patients was large.
3) The most common chief complaint was dental caries. The percentage of children treated for dental caries, however, decreased gradually. On the other hand, chief complaints of tooth injury, oral examination requesting caries prevention and treatment of malocclusion were increased.
4) There was a large number of children under age 1 whose chief complaint was tooth injury, and there was a large number of oral examinations requesting caries prevention among 2-year-old children.
5) New patients visiting the Pediatric Dentistry department of Kanagawa Dental College Hospital came mainly from within the boundaries of the city of Yokosuka and Yokohama. To reach our hospital, more patients used public and private transportation than those who came on foot. Conclusions:
The phenomenon of reduction of the child population in Japan is unavoidable. The Pediatric Dental Hospital attached to Kanagawa Dental College needs to maintain its status not only as a provider of high quality tertiary medical care but also as an educational institution. It is therefore very important to gather and spread information and to provide attractive and effective dental health care programs for children and guardians as well as to foster a closer connection with local medical facilities for undergraduate dental students and post-graduate dental professionals undergoing clinical education.

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Although numerous studies have shown that oral disease, such as temporomandibular disease and bruxism are associated with mastication and jaw-closing motion, the mechanism has not yet been fully elucidated.
In this study, in order to elucidate the mechanism of the oral conditions and the chewing motionmechanism, we analyzed the trigeminal mesencephalic nucleus neurons that are projections of periodontal pressoreceptors from periodontal ligaments by using retrograde fluorescence staining.
The fluoresence staining of the originated neurons of the trigeminal mesencephalic nucleus was observed and the results were obtained as follows:
1. In retrograde labelling with 2% dextran, tetramethyl rhodamine, the labelling neuron was not recognized in any of the groups after administration of 2% dextran, tetramethyl rhodamine. In retrograde labelling with 10% dextran, tetramethyl rhodamine, only one retrograde labelling neuron of one rat was recognized out of 12 rats after administration of 10% dextran, tetramethyl rhodamine.
2. In retrograde labelling with 2% dextran, rhodamine B, the retrograde labelling neuron was not recognized in any interval after administration of 2% dextran, rhodamine B.
3. In retrograde labelling with 10% dextran, rhodamine B, retrograde labelling neuron was not recognized 1 day after administration, although the sum of two labellinng neurons obtained from each one of two rats were recognized out of 12 rats 2 days after administration. The sum of six labelling neurons obtained from 4 rats was recognized out of 12 rats 4 days after administration.
4. We carried out retrograde labelling with 20% dextran, rhodamine B. As a result, the sum of two labelling neurons obtaining from each one of two rats, were recognized out of 12 rats 4 days after administration.
These results have shown that the injection into periodontal ligament is able to label the trigeminal mesencephalic nucleus neurons that are projections of periodontal pressoreceptors in the mandibular molar retrogradely.
The number of retrograde labelling neurons was small however and the probability of labelling neurons was low, so that further study is needed to analyze the procedure of retrograde labelling and injection area of the neuronal tracer.

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With treatment of malocclusion in children during the mixed dentition period, it is desirable that close collaboration should be established between the pediatric dentistry and orthodontic departments. If both departments were functionally integrated into one based on the principles of rationalism, it would be possible to examine, diagnose and treat the same patients from infancy to adulthood and further into advanced age on the same time axis. In this paper we shall report on the results of a survey of characteristic changes in the patients who visited our hospital for correction of malocclusion in 1991 and 2001.
The year 2001 was the year when the pediatric dentistry and orthodontic departments were united in accordance with a structural reform program.
A summary of our findings is as follows:
1. The number of patients who wished to have malocclusion corrected did not increase in 2001.
2. The mean age was 6 years 7 months for the malocclusion patients who visited the department of pediatric dentistry during 1991 and 14 years 5 months for those who visited the department of orthodontics during that year. When the pedodontic and orthodontic patients were combined, the mean age came to 13 years,4 months. This figure can be compared with the 15 years 5 months for those patients visiting the newly unified pediatric/orthodontic department during 2001.
3. Of all the malocclusion patients who came for corrective treatment, those patients with mixed dentition accounted for a larger percentage in 2001 than in 1991.
4. Among those who came for occlusal correction during 2001, cases of crowding of teeth were found to be the largest in number, followed by crossbite cases and maxillary protrusion cases, in that order. The types of malocclusion varied greatly, showing characteristics of the so-called urban type distribution.
5. The most common initial appliance used for occlusal correction for the patients who visited the pediatric dentistry department or the orthodontic department during 1991 was the multiphase bracket (premolars extracted). In 2001, the multibracket was also the most commonly used initial appliance, but it was used without removal of premolars.
These findings suggested that under the present system, treatment was being given on the time axis associated with growth and development thanks to smooth liaison between pediatric dentists and orthodontists, which was impossible under the old dental service system.

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We discussed the influence of the tongue rest position on the anterior occlusal relationship among children with tongue thrust.24 children with anterior malocclusion in the mixed dentition period were classified into two groups, the habit group and the non-habit group. The habit group was divided into two types, the open bite type and the anterior cross bite type, and the non-habit group was also divided into two types, the anterior cross bite type and Class I crowding type, according to their clinical diagnoses. The ultrasound mid-sagittal images of their tongue movements during deglutition were recorded using the B-mode. In order to analyze the degree of flatness of the tongue dorsum both when swallowing and resting, the traced tongue dorsum images were divided into quarters mesiodistally and the tangent of each quarter was calculated. We defined the averaged absolute values of the four tangents as the CTD (Curvature of Tongue Dorsum) of each child, and analyzed the relationship between the CTDs and the overbite figures which were calculated from their lateral cephalograms.
There were significant correlations both between the CTD during swallowing and the overbites and between the CTD during resting and the overbites. There was no significant correlation between the CTD during swallowing and the CTD during resting. It is, therefore, suggested that the tongue rest position influenced the anterior occlusal relationship in addition to the tongue swallowing position. The mean of the CTDs of the open bite type in the habit group was the lowest, and that of the anterior cross bite type in the habit group followed. The variations of the CTDs in the habit group are significantly smaller than those of the non-habit group. It seemed that the tongue dorsum of the habit group was by and large flat and the habit group had the characteristic shapes of the tongue dorsum.

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The purpose of the present study was to determine the diagnostic value of the electric pulp test for primary anterior dentition, and influences of trauma on the pulp vitality in children aged 2-7 years old.77 patients corresponding to 152 traumataized teeth were assessed clinically and radiographically, and 63 non-traumataized teeth were tested as the control. The upper central incisors involved 60.5%of the total number of teeth.
According to diagnos is, subluxation and intrusion were the most frequent (78%), with a redomoninance of lateral luxation, followed by crown fracture and alveolar bone fracture. The ages of the chidlren at the time of accident ranged between 0-6 years old.
The results were as follows. Pulp necrosis and periapica l periodontitis (PN) were diagnosed in 30teeth (19.7%). The frequency of PN came to 60% of the teeth with negative response to electric stimuration during the follow-up period under 5 years of age. Falsenegative reading indicates pulp canal obliteration, yet the patient will be unresponsive to the electric pulp test. All positive response to electric stimuration indicated clinical intact pulp. The presence of intrusion seemed to increase the risk of PN in comparison with subluxation.

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In this study, in order to hasten the bone instruction we developed the sintered hydroxyapatite (HAP: Ca₁₀(PO₄)₆(OH)₂) derivatives with porosities, by adding of calscium carbonate or β-tricalcium phosphate (β-TCP: β-Ca₃(PO₄)₂) with bioresorption to HAP using Spark Plasma Sintering. The sintered HAP derivatives were then implanted into the tibia of rat. The effects of additional calcium carbonate or β-TCP to HAP on the new bone formation were examined.
The contact ratio of the new bone onto the HAP carrier was strongly dependent on their composition. Theadditionof β-TCP to the HAP resulted in the harshening the new bone formation along the carrier surface and in an increase in the contact ratio of the new bone.

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One-bottle self-etching systems have recently been develop ed to reduce the number of clinical steps for resin application and have been widely used in dental clinical practice. The purpose of this s tudy was to evaluate the bonding abilities of five one-bottle adhesive resin systems (self-etching syst ems)using the microtensile bond test, fractography with a scanning electron microscope (SEM), and the silver-stained interfacial observation using a transmission electron microscope (TEM).
The bond strength was below 50 MPa for all the adhesive systems, indicatin g that there was no improvement in bond strength compared to traditional systems. SEM and TEM observations indica ted that the amount of nanoleakage formation was relatively small due to the combined structur e among the collagen fibers, dentinal hard tissue, and resin of the one-bottle resin systems. Severe nanole akage and water tree or bubble formation were however observed in the bonding resin layers because of their high content of water or solvents. It was thought that the reason for nanoleakage formation w as phase separation between resin monomer and water, or water sorption of resin from the dent inal tubles during bonding procedures. Since such nanoleakage will be a pathway of water invasion of the adhesive interfaces and result in reduction of long-term durability, a hydrophobic nature is requir ed for chemical formulation of bonding resin.

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The semiconductor titanium dioxide (TiO₂) has been recently used in many fields because of its characteristic photocatalytic reaction property.
Toothbrushes with a semiconductor were clinically produced. The purpose of this study was to determine the photocatalytic effect of semiconductor TiO₂ on cariogenic bacteria S. mutans and to support its efficacy. The possibility of enhancement of the photocatalytic effect using a solar battery was also examined. The following results were obtained.
1) The photocatalytic reaction of TiO₂ inhibited acid production of S. mutans.
2) The photocatalytic reaction of TiO₂ showed antibacterial effect on S. mutans.
3) The photocatalytic effect of TiO₂ expands from the position of the TiO₂ electrode bar to the surrounding area.
4) The photocatalytic effect of TiO₂ was enhanced by the solar battery.

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During dental treatment, fear and anxiety can often be induced in patients by various stimuli such as the environment and activity around the dental chair and the degree of the treatment (painful or not). This can result in stress that subsequently causes avoidance of treatment and lost opportunities for early treatment. Thus accurate evaluations of stress in patients are important to achieve suitable dental treatment. Recently, salivary alpha-amylase activity has received attention as an index of psychological stress. We measured salivary alpha-amylase activity in children before and after treatment, and the relationship between the degree of stress and the activity of salivary alpha-amylase was assessed by comparing the changes in the activities following dental treatment. The activities were significantly increased following treatment in 75% of the subjects (p<0.05). Specifically, there was a significant increase after surgical treatment (p<0.05); suggesting a correlation between the degree of treatment and stress. The results indicated that changes in salivary alpha-amylase activity may represent an index to monitor stress in children. We concluded that monitoring the activity of salivary alpha-amylase is a useful, easy to implement and non-invasive method to assess the stress caused in children by dental treatment.

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Causes of tooth loss are mainly dental caries and periodontal diseases, which are lifestyle-related diseases caused by poor lifestyle habits. Since they originate in childhood, dissemination of oral health knowledge, promotion of health through appropriate guidance, and establishment of healthoriented behavior during this period are essential for prevention of these diseases.
To obtain appropriate indexes for oral hygiene instruction during chil dhood, we undertook regular dental health examinations, performed caries activity tests (cariostat®), and conducted with respect to investigations using questionnaires 780 fifth graders in 13 elementary schools in Nerima Ward in Tokyo, and analyzed the relationship between the results of continuous caries activity tests (cariostat®)and lifestyle habits. The following results were obtained:
1. The questionnaire findings and dental caries incidence correlated to“tooth-brushing habits,”“toothbrush replacement period,” “eating and drinking after tooth-brushing,”“regularity of breakfast,” “dental caries prevention,” “gingival condition,” and“cariostat scores.”
2. The cariostat scores correlated to the“presence of dental caries,” “tooth-brushing habits,”“frequency of tooth-brushing,”“eating and drinking after supper,” “amount of between-meal snacks,”“time of taking between-meal snacks,” “juice intake,” and“self-awareness of mouth odor.”

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The dentigerous cyst is the second most common odontogenic cyst. By definition, a dentigerous cyst is associated with the crown of an unerupted and impacted permanent tooth. They are not cornmon, however, when associated with a supernumerary tooth. There has been only a small number of studies on the association of dentigerous cysts with a supernumerary tooth. We report on a case of a dentigerous cyst associated with an impacted supernumerary tooth in the maxillary right anterior region which occured during an interruption, and which was discovered during periodic recall at our clinic. The patient was a 13-year-old boy. At the age of 10 the supernumerary tooth in his right incisor region of maxilla was found in our clinic using X-ray photo. But extraction of the tooth was not performed due to his low systemic physical condition and we decided to keep following this up. He had a few month history of progressive painless swelling of the maxillary right anterior mucogingival fold. He was diagnosed as having a Wilson-Mikity syndrome at when newly born and was also diagnosed as having epilepsy, cerebral palsy and mental retardation. The extraoral examination revealed swelling of the right upper lip and intraoral examination revealed that fluctuating buccal swelling covered with blue-violet appearing mucosa expanded from the right central incisor to the canine region. The occulusal radiographs showed a well-defined unilocular radiolucency containing a supernumerary tooth. We performed enunciation of the cyst and extraction of the supernumerary tooth under local anesthesia.17 days after the operation, we recognized the region was infected and performed a antibiotic therapy. Postoperative course was uneventful for 2 months following the surgery. The progress of the supernumerary teeth should be followed up both clinically and radiographically at adequate intervals, to allow early identification of pathological changes. This case suggests the importance of having a comprehensive and continuously examination in the case of tooth anomaly for pediatric and disable people.

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In the clinical practice of pediatric dentistry we occasionally encounter patients with submerged primary teeth. Submerged primary teeth, with no other symptoms, can cause abnormal eruption of succedaneous teeth, resulting in impaction of food as well as dental caries. The submerged tooth may be extracted immediately or its condition observed periodically in the hope that the tooth might resume eruption to the occlusion line.
The submerged tooth which is missing a succedaneous tooth should nevertheless be preserved as long as possible from the point of view of maintaining the space. When it appears that it might cause obstruction to the eruption of succedaneous teeth, it is of great importance that the tooth be extracted immediately. Here we report on a case of submergence and impaction of both lower second primary teeth without succedaneous teeth. We therefore extracted both second primary teeth which had been submerged and impacted, and undertook minor tooth movement. At the same time we performed primary oral care and this enabled us to confirm that there were indications that the bone level would catch up to the normal level.

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Respiratory disorders are aggravated according to age in many instances involving patients with severe cerebral palsy (CP). Most anesthetics have stronger effects on older people. It is therefore hypothesized that older CP patients show airway obstruction more easily than younger CP patients during dental treatment under general anesthesia without intubation. We investigated management using propofol without intubation, which had been performed in our hospital during dental treatment for 29patients with cerebral palsy in order to clarify the relationship between the respiratory disorder and age of CP patients under general anesthesia. The following results were obtained.
1. The doses of propofol administered to the patients did not change significantly with aging.
2. The ratio of the occurrence of body movement during dental treatment did not show a significant relationship to age.
3. The ratio of the occurrence of airway obstruction during the management of the oldest group was significantly higher than that of the younger groups.

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The purpose of this study was to analyze several cases, and investigate the usefulness of the limited area cone beam CT (CBCT) in pediatric dentistry.
The cases analyzed involved ortho-CT and 3 DX Multi-Image Micro CT (Morita Co., Japan) from January 1998 to December 2003 in the Radiology department and ordered by the department of Pediatric Dentistry section of Nihon University Dental Hospital. The conditions of the requests (objects, clinical diagnosis etc. ) the average, maximum and minimum ages of patients and gender were investigated.
The total number of cases over the 6 years amounted to 455. The distribution of the requests was as follows; impacted supernumerary teeth 51.0%, disorder in tooth eruption 26.8%, TMJ 9.2%, and other diseases 13.0%. The average age of the patients was 8 years and 4 months (Max; 18 years and 2 months, Min; 2 years and 10 months).
According to the analysis of 455 cases, it was showed that CBCT is very useful in pediatric dentistry.

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