The situation of medical malpractice was investigated among the departments of 29 universities by the Japanese Association of Pediatric Dentistry, to collect the basic data for the establishment of a preventive system in the future.
The subjects were 59 cases that were defined as medical malpractice in pedodontical clinics from 29 universities between Jan.1989 and Dec.1995.
The changes occurred in 17 universities out of 29,59 cases in all, none in the other 12 universities.
It included 33 cases of medical dissatisfaction,12 cases of medical fault,10 cases of accidental events and 4 cases of inevitable accidents, with medical dissatisfaction the most.
There were 16 cases of changes of malpractice in 1994,12 cases in 1995 and 10 cases in 1993, in decreasing order.
By month the distribution was 10 cases in June,9 cases in November and the least,1 case, in March.
They occurred the most in the morning in 38 cases, in afternoon 16 cases and at other times (including the unknown) 5 cases.
Eleven cases occurred in children 3 years old,8 cases children 4 year-old and 8 cases in children 5year-old, in decreasing order. Slightly more female patients were involved. The changes occurred more during reattendance.
Countermeasure against medical changes of malpractice and problems of medical dissatisfaction should be investigated in detail in the future.

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We studied 12 children in the mixed dentition period who were diagnosed as having an open bite or an open bite tendency with tongue thrusting who were treated with two types of removable habit breakers, a Hawley's type retainer with incorporated tongue cribs (the Plate group) and a bionater for open bite (the Bionator group). We compared their lateral cephalograms at both the time of examination and the time of removal of the appliances (around 1 year later) with the standard values of the cephalograms of groups of the same age.
The results were as follows.
1. At the time of the examination, besides significantly smaller over-bites in both groups than those of the standard value, the distance between the Prosthion and the Infradentale in the Plate group was significantly longer and the angle of the upper central incisor to the SN plane in the Bionator group was significantly higher than those of the standard value.
2. At the time of removal, the over-bites had changed to the range of from 1.0 mm to 0.2 mm in the Plate group, and from 1.5 mm to 0.2 mm in the Bionator group.
3. At the time of removal in the Plate group, the lower central incisor angle to the mandibular plane became significantly smaller, and the upper central incisor angles had become nearer to the standard values on the whole. The distance between the Prosthion and the Infradentale was no more significant compared with the standard value. There were more changes of the linear measurements, however, than those of the standard values between the same age groups.
4. At the time of removal in the Bionator group, the lower central incisor angle to the mandibular plane also became significantly smaller. The reduction of the labial inclination of the central incisors to some extent, with the significant labial movement of the point A, seemed to be brought about from the myoplate added to the bionator. The changes of the linear measurements were roughly equal to those of the standard values between the same age groups.
5. To reduce the excessive lingual inclination of the lower central incisors, it seemed necessary that the design of the tongue crib should be changed in the Plate and the adjustment methods should be improved in the Bionator.

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The purpose of this study was to examine the size of the teeth, dental arch, crowding, and craniofacial morphology in children from nine to ten years of age and the relationship to the timing of the formation of the permanent teeth. We further investigated whether the formation stages of the lower teeth of the subjects with negative overjet develop further ahead than in the case of subjects with positive overjet.
The materials consisted of dental casts, cephalometric X-rays and panoramic X-rays of 94 males and 154 females from nine to ten years of age taken from the files of the Department of Orthodontics, School of Dentistry, Kyushu University. The results were as follows;
1. Tooth formation developed ahead more in females than in males and in the lower teeth more than in the upper teeth. The difference between upper and lower teeth was remarkable in the lateral incisor.
2. The arch width, upper in females and lower in both sexes, was in inverse proportion to tooth formation. Moreover, the arch length was in inverse proportion to the lower tooth formation in males.
3. We were not able to find a significant relationship between the crowding of the mandibular incisors and tooth formation.
4. There was a significant relationship between the craniofacial morphology, such as a steep mandibular plane, posterior rotation of the mandible, long anterior facial height, palatal inclination of the maxillary incisors and large overbite, as well as early developed tooth formation, particularly in males than in females.
5. There was no significant relationship between the size of both jaws and tooth formation.
6. We compared the tooth formation of two groups that were classified according to whether the overjet was positive or negative. The tooth formation, however, did not show significant differences between two groups.

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Hitherto, rotary cutting equipment has been the most commonly used in the cutting of teeth in clinical dentistry, but its use is accompanied by pressure, vibration, noise, heat and pain. As Kinetic techniques tend to reduce these unpleasant effects, the authors have conducted a series of basic research projects concerning the application of kinetic energy within the area of pediatric dentistry. In the present study, histological serial sections were undertaken and cavity shapes and other features were observed in order to better understand the details of cavities formed using an air-abrasive cutting machine. The KCP-2001 J air-powder abrasive system was used to prepare Class 5 cavities on 50 teeth of 6 adult dogs. Following decalcification of the specimens, paraffin serial sections were done and hematoxylin-eosin staining was performed. Sections were observed and photographed under an optical microscope, and the resulting images were processed with an image scanner. Computer analysis was then used to measure the dimensions and features of the prepared cavities.
The following conclusions were obtained:
1) Cavities prepared with air-abrasive cutting instrument take mainly the shape of a slightly outwardly spread “U”.
2) The cavity walls of preparations done by air-abrasive cutting system are relatively smooth.
3) Even though the used air-abrasive cutting system without water spray, no burning was observed on the tooth material surrounding the cavities.
4) Although it is difficult to form cavities with distinct point angles or line angles using the abrasive cutting system, extremely precise long cavities can be prepared.

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To study the age at which children are ready for oral examination, oral examination was carried out on 154 children aged 1-5 years, and the relationship of their responses to the examination and the state of their development was analyzed using AIC.
1. Whether the child was ready for oral examination or not closely correlated to the developmental age, chronological age, and degree of independence in ADL.
2. The optimal cut-off point concerning the readiness for oral examination was 2 years and 6 months for the chronological age, and was between 2 years and 4.5 months to 2 years and 10.5 months for the developmental age.
3. Children aged 2 years and 6 months or older in their chronologeical age are considered to be ready for oral examination.

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Dentists can contribute to the safety of the players in various sports against sports injury through making protector in the oral and facial areas. We selected a mouth formed type of mouth guard adaptable for each individual and checked the comfort level in wearing it, in order to know what is important in producing a comfortable and effective mouth guard.
Twenty high school students who were members of rugby football clubs voluntarily took part in this investigation. A mouth guard was made by each player following the instructions and also another mouth guard was prepared by a dentist using the plaster model of the player. Comparison of the fitting of these mouth guards was conducted by measuring the thickness of the silicon rubber impression material placed between the model and the appliance. The subjects answered the questionnaires about the mouth guard after one month of use.
The fitting of the mouth guard made by the dentist was significantly better than that made by students. According to the questionnaire, the mouth guard made by a dentist was not necessarily accepted as a very good appliance when it did not have the impression of the lower teeth. On the contrary it resulted in a bad feeling when worn. They listed the following demands as conditions important to a good mouth guard. #1 Easy breathing #2 Fitting and #3 The prevention of cerebral concussion. To the question “Are you willing to use the mouth guard from now on?”, seventeen out of eighteen answered “Yes”, only one answered “I don't know”. This result indicates the latent demand for a mouth guard among contact sports players.

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Commercially available bonding-agents and composite resins were employed in this study to investigate the cytotoxicity of dentin-bonding composite resin, using human gingival fibroblasts in cell cultures. The cells were seeded on the resin surfaces cured with various periods of light illumination. The cells were cultivated for 1,3 and 6 days, and cell morphology was observed using a phase contrast microscope and a light microscope. The number of living cells on the uniform area of the resin surfaces was counted for 1,3 and 6 days of cultivation for quantitative evaluation of cytotoxicity. After 24 hours of obsevation, the cells were attached to the surfaces of the bonding-agents and composite resins. The cell attachment rate was however suppressed in comparison with the growth of the control cells. The greater cell growth of LB and AP-X was demonstrated with the longer light illumination. On the other hand, the cell growth of MP and Z 100 was not affected by the number of the seconds of light illumination. The number of cells did not increase as much as the control cell growth in 1,3 and 6 days of culture. However, the lesser cytotoxicity of the cured bonding agents and cornposite resins was suggested by the result of the adhesion and growth of cells on the resin surface.

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The Kanagawa Dental College Pediatric Dentistry Department founded on investigation of the recall system. The 2418 patients, under the age of 9, were included in the investigation. The patients first visited the hospital between January 1970 and December 1974. The patients follow up period was 14 years.
The results were as follows.
1) The average age of the first-visit patients was 4 years and 4 months, and the largest number was for 3-year-old patients. About 85.2% of all the patients was included between the ages of 2 and 5.2) The average period of the recall continuation was 3 years and 4 months. Among them 241 (10%)patients did not appear for the recall.
3) The average continuation period of the 0-year-old patients was the longest (5 years and 6 months)and that of 8 and 9-year-old patients was the shortest (2 years and 4 months).
4) The rate of rejection within 1 year of the patients who first came to the hospital at the ages from 6years up was relatively higher. The rejection rate of the patients of the ages between 0 and 5 at their first visit was not marked before and after 6 years old.
5) The rate of patients domiciled in the vicinity of the hospital (necessary time for attendance less than 1 hour) was 74.7% and that of the distant patients was 25.3%. The number of the distant patients showed a tendency to be lower within 1 year.
6) The period of the recall continuation of the dwelling nearly patients was higher if they were younger, while that of the dwelling for away patients was higher if they were older.

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A new light-ctivated glass ionomer cement specifically designed for pit and fissure sealant was examined as to the cytotoxic effect on the cultured human gingival fibroblasts.
Specimens of the light-ctivated glass ionomer cement meterials with various light illumination periods of 0-60 seconds were prepared, while the individual liquid and powder were prepared separately. Cultured human gingival fibroblasts were exposed to these specimens indirectly through the intervening agar plate for 24 hours at 37°C in a 5% CO₂, humidified atmosphere. The round-haped affected area showing cell death developed in the culture beneath the specimen as a result of the cytotoxic effect of the constituent element(s) of the cement meterial and the size of the area was calculated in mm2 to evaluate the degree of cytotoxicity.
The results showed that the liquid provided a high level of cytotoxicity, while the powder had no deteriorative effects on the cell vitality of the cultured fibroblasts. The cement material of the mixture of the liquid and powder without light illumination showed an intensive cytotoxicity, but it decreased according to the increase of the duration of the light illumination period. Cytotoxicity completely disappeared with more than 30-econds of light illumination.
These results demonstrate that the light-ctivated glass ionomer cement used in this study was innoxious when more than 30-econds of light illumination was given, which also indicates that the 30-econds of light illumination allows the complete setting of the cement material to prevent disintegration of the cement structure and consequent dissolution of the constituent elements even in the presence of the wet agar.

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We investigated the actual conditions of restorative treatment for young permanent teeth in the Pediatric Dental Clinic of the Tokyo Dental College from April 1993 to March 1994. The materials investigated in this study were 1700 permanent teeth from 758 patients aged from 5 to 19 years.
The most frequently treated restorations were composite resin restoration for the anterior teeth and metal inlay restoration for the posterior teeth. One tooth surface a tooth was the most frequently restored for both anterior and posterior teeth. Metal inlay restoration was performed frequently to two tooth surfaces a tooth, and composite resin restoration was performed frequently to one tooth surface a tooth for both anterior and posterior teeth. Almost of all of the teeth restored with glass-ionomer cement or silver amalgam involved one tooth surface a tooth.
The OL-cavity form in maxillary first molar, OB-cavity form in mandibular first molar were the most frequently prepared with metal inlay restoration. The cavity form included the M in the anterior teeth and the M or B-cavity form in the posterior teeth were prepared frequently for composite resin restoration. Cavity forms of each restoration took into consideration the characteristics of each restorative material. It seems that the glass-ionomer cement and silver amalgam were used for temporally restorations, so that, these two restorations were performed on the younger patients more frequently than on the patients receiving metal inlay restoration and composite resin restoration.

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The purpose of this study was to evaluate the clinical usefulness of sedation using sublingual administration of midazolam together with nitrous oxide/oxygen inhalation. The clinical usefulness was evaluated by the evaluation of the clinical sedative effects, and the status of adverse effects and discharge.
The subjects were 21 mentally handicapped patients, aged 6 to 21 years, all of whom had previously exhibited highly combative and resistant behavior toward dental treatment under nitrous oxide/oxygen inhalation sedation. In this study, they received 0.2 mg/kg of sublingual instillation of midazolam, then received dental treatment with nitrous oxide/oxygen inhalation (20-40% N₂O/80-60% O₂).
Four of the 21 patients (19.0%) exhibited combative and resistant behavior toward the sublingual administration of midazolam. The initial sedative effects appeared within 5-10 minutes after sublingual midazolam administration. One patient rejected the nasal mask and refused to inhale the nitrous oxide/oxygen. The range of the success rate evaluated as both “markedly effective” and “effective” in each dental procedure was 65.0-90.5%. The injection of local anesthesia showed the lowest success rate among all of the procedures. The majority of the patients recovered within 150 minutes of the sublingual instillation of midazolam. At no time during the course of this study were any adverse effects observed.
Sixteen of the 21 patients (76.2%) were able to keep midazolam in their sublingual for more than 21 seconds. The rate of the clinical usefulness was 76.2%. The clinical usefulness tended to be influenced by the length of time of keeping midazolam in the sublingual. Comparing the clinical usefulness of keeping midazolam in the sublingual more than 21 seconds and of less than 21 seconds, we found that better effect was obtained from the former case. We believe that this technique is a useful conscious sedation during dental treatment.

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It is postulated that mothers have some effect on dentists during the treatment of their children. Therefore, we examined several reports demonstrating that mothers have an effect on dentists during the treatment of their children. It was said that the individual personalities of the dentists were related principally to their feeling psychological stress, and it became increasingly apparent that there were important individual differences in response to stress. The strength, duration, and timing of the stresser and the specific makeup of the individual determine how he/she reacts to the stresser to produce a particular stress response. Accordingly, with 23 dentists from the Department of Pediatric Dentistry, Hiroshima University School of Dentistry as subjects, we analyzed the effect of mothers on dentists during the treatment of their children using the Psychological Stress Response Scale and YG (Yatabe-Gilford Character test) Personality Test. We examined the results by analyzing the relationship between the personalities of the dentists and their psychological stress scores. The findings were as follows:
1. As for personality types, the D-type (director type) accounted for the largest percentage of dentists 34.8%, while of the 26.1% were C-type (calm type),17.4% of the A-type (average type),13.0% of the B-type (blast type), and 8.7% of the E-type (escape type).
2. It was found that there was a significant correlation between the psycholigical stress score and the four scales that measured emotional stability (depression, cyclic tendency, inferiority feelings, nervousness)within the 12 scale YG personality test. No significant correlations were found with the three scales that measured social adaptability (lack of objectivity, lack of cooperativeness, lack of agreeableness), and the five scales that measured social direction (general activity, rhathymia, thinking extraversion, ascendance, social extraversion).
These results suggest that, concerning the relationship between stress effected by mothers on dentists during treatment of their children and the character of the dentists as measured by the YG Personality Test, the scales used to measure emotional stability were highly relevant while the scales used to measure social adaptability and social direction were not.

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“The Test of Young Children's Behavioral and Emotional Estimate in the Dental Setting” estab lished at the Department of Pediatric Dentistry, The University of Tokushima School of Dentistry, was evaluated in 82 kindergarten children (40 male,42 female) three year zero month to six year ten month old and in 88 school children (34 male,54 female) six year eight month to twelve year two month old and their mothers at 17 private dental offices.
The results are summarized as follows:
1. The success rate of the Test was 74.4% in kindergarten children with an average age of five years and three months.
2. The success rate of the Test was 86.4% in school children with an average age of eight years and eleven months.
3. The Test was conducted without difficulty at each private dental office. These results suggest that “The Test of Young Children's Behavioral and Emotional Evaluation in the Dental Setting” is to a wide extent very useful in clinical use in kindergarten and school children.

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The degree of tooth formation were studied quantitatively way using 11,200 orthopantomograms (5,700 males and 5,500 females) obtained from Japanese children aged 2 to 14.
The assessment was based on a slight of modification Moorrees, et al. tooth formation stages. They were divided into 14 stages for the molars and 13 for the premolars. Each stage consisted of points ranging from 0 to 14.
The results obtained were as follows:
1. The formation was faster in all teeth for female than for male, this tendency being especially true during middle stages of tooth development.
2. Statistically a tooth on one side developed at the same rate as its counterpart on the other side regardless of sex, or arch differences.3. The norms of the formation for Japanese permanent molars may be applied to daily dental practice.

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Supernumerary teeth are frequently found in the maxillary anterior region, but they are found less in the mandibular anterior region than in the maxilla.
It is reported that the frequency of missing successors was 50 percent when the fused teeth were present in the deciduous dentition.
Rare cases of supernumerary teeth in the mandibular anterior region of four child patients were reported.
Three cases had a fused deciduous tooth, it was, however, unclear whether there was a fused deciduous tooth or not in our case.

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In general, patients with congenital cyanotic heart disease are sensitive to infectious endocarditis. In the event that a bacteremia occurs in a patient with a circulatory shunt, bacteria in the venous circulatory system are allowed to pass directly to the brain without going through the normal pulmonary circulation having a filtering capability and may cause a brain abscess. The patient in this case was a female at the age of 9 years and 7 months with congenital cyanotic heart disease (single ventricle, coarctation of aorta, mitoral stenosis and atrial septal defect). A brain abscess developed after the tooth extraction but was successfully treated through drainage and administration of antibiotic through neurosurgery. The brain abscess in this patient. was considered to have been caused by bacteria that might have been reached the brain through her right-to-left shunt from the forcus in the oral cavity after tooth extraction. As an intraoral lesion in children with congenital cyanotic heart disease may directly cause a focal infection, antibiotic prophylaxis and subsequent careful observation are recomended especially for invasive treatment.

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We experienced a case of Stevens-Johnson syndrom in a boy at the age of 8 years and 7 months. Our findings are as follows:
1. Dental anomalies such as white spots of the enamel, anomaly of the root formation and enamel hypoplasia were observed. As the time that the Patient was diagnosed as Stevens-Johnson syndrom corresponded with the time his crowns and root were stating to form, it was suggested that the occurence of the teeth disturbance was associated with Stevens-Johnson syndrom. A bald tongue was also observed and is considered to have been caused.
2. Mobility due to anomaly of the root formation (short roots) was observed in the maxillary bilateral incisors, mandibular bilateral incisors and mandibular right lateral incisors.

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We have applied 1.23% phosphoric acid fluoride foam with artificial sweetenings to patients of Pediatric Dentistry of The hospital of the Osaka Dental Univerity, Handicapped Dental Clinic in the Osaka Dantal Association and general dental office from January 10,1994 to August 31,1996.
The artificial sweetenings in the fluoride foam were of five kinds. We applied this to fifty patients including normal children, handicapped children and adults. We set up a questionnaire concerning the fluoride foam.
The results were as follows;
1. We have not found any difference in the taste of the artificial sweetenings (cinnamon-apple, razuberry, candyminto, grape and babulgum) in the fluoride foam.
2. We have found differences of taste according to the age and sex of the patient.
3. The application of the fluoride foam was performed using cotton rolls, a tray and a tooth brush. We found application with the tooth brush to be better than other ways.
4. We did not find any coloring or stimulus on the tooth and oral mucosa by the fluoride foam.
5. The application of the fluoride foam was effective for the prevention of dental caries and hyperesthesia.
6. Because the fluoride was applied as a foam, the total mass of the fluoride was actually less.
7. There was a disadvantage in that the fluoride foam gelled in the vessel.
8. The dental treatment of the normal children, handicapped children and handicapped adults was easily performed by the application of the fluoride foam and they cooperated better during the dental treatment.

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The authors analyzed the psychosocial background of an 11 year 7 month old female child who experienced difficulty in her dental treatment due to being unable to follow the instructions of her dentist which resulted from her being unable to communicate verbally with the dentist. The child refused to attend school, and showed weak responses to stimulation and a tendency to retire within herself when she felt anxious: there facts were considered to indicate a low level of self-confidence. Therefore, in order to reduce the level of her anxiety and tension resulting from the dental treatment, we included sedation through inhalation of nitrous oxide-oxygen in her treatment as a method of systematic desensitization, one form of behavioral therapy. We reduced the concentration of nitrous oxide and the inhalation time at each step of the treatment, and at the same time, we praised her attitude toward the treatment to increase her confidence in the treatment. As a result, she became capable of following the dentist's instructions from the 9 th treatment, and thus could subsequently be treated under normal conditions.

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