A number of previous studies have reported the effects of breathing on maxillofacial morphology in childhood. However, accurate findings for evaluating the airway are difficult to acquire because it analysis of upper airway ventilation condition can be problematic. To improve this situation, we developed a three-dimensional upper airway model using cone beam CT data for highly precise analysis of the upper airway with computational fluid dynamics used to assesses the flow of air. As a result,we found that the pharyngeal airway morphology in Class III children showed that the long diameter type of pharyngeal airway and wide diameter type of pharyngeal airway with low tongue posture were shown. On the other hand, in Class II children, upper airway obstruction can be a cause of excessive vertical maxillofacial growth, and that this may be attributed to various parts of the upper airway, such as the nasal, nasopharyngeal, oropharyngeal, and hypopharyngeal airway. It was also revealed that when nasal obstruction is improved by rapid maxillary expansion, the volume of the pharyngeal airway increases and low tongue posture is improved. Thus, we succeeded in clarifying the mechanism by which rapid maxillary expansion improves upper airway obstruction. Pediatric obstructive sleep apnea syndrome occurs at a high frequency, with a prevalence of 2% in otherwise health children. With use of available medical treatment, the success rate is 70%. In the future, we hope to examine the efficacy of application of orthodontic procedures for treatment, such as rapid maxillary expansion or mandibular forward induction, for social contributions from the field of pediatric dentistry.

The aim of this study was to investigate the purpose of a visit to a private pedodontic clinic of patients aged 0 to 1 year. A survey was performed of 464 infant patients who visited during the past 12 -year period. The purpose of the visit and related matters were surveyed using proprietary questionnaires. Correlations among the obtained data were statistically analyzed, and the following results obtained.

1.For age at the initial visit, 16-19 months in females and 12-15 months in males were predominant.

2.The number of males significantly increased from the age category of 4-7 months to 12-15 months,while the number of females significantly increased from the age category of 8-11 months to 12-15 months.

3.As for the purpose of the visit, dental caries was most frequent at 35%, followed by oral examination and prophylaxis at 32%, and injury at 15%.

4.As for the ratio of purpose by age category, dental caries was highest in the 12-15 month old period, oral examination/prophylaxis was highest in the 16-19 month old period, and injury was high est in the 8-11 month old period.

5.The number of sibling-existent patients was significantly greater than that of no sibling-existent among those who visited for dental caries and oral examination/prophylaxis.

6.As for the age difference of an existent sibling, under 3 years was answered most often for dental caries, while the ratio of under 2 years to under 1 year was significantly different for injury.

The results of this 12-year retrospective survey revealed variations in regard to the purpose of a dental visit by 0- to 1-year-old children, even among those of the same age. In addition, they suggest that existence of a sibling and age difference of the sibling are influential factors.

A dental check­up performed for a child patient generally includes tooth cleaning instruction related to the dental condition, eating guidance, professional mechanical tooth cleaning, instructions regarding caries prevention, topical fluoride application, and a bite­wing X­ray examination to reveal proximal caries. Such a protocol is superior to screening conducted with a large population for the purpose of preventing dental disease. However, the importance of regular dental check­ups is not well recognized in Japan as compared to other countries. I conducted a questionnaire survey in order to understand the current situation in Japan in comparison with other countries. The findings showed that the ratio of Japanese 12­year­old children who received regular dental check­ups was 44%, which was less than half of most other countries investigated. The main reasons noted for not visiting a dentist in Japan were because “the child had no cavities”, “large economic burden”, and “no time to spare”. In answer to the question “Has your child ever been absent from school because he/she visited the dentist for a check­up?”, 98% of the Japanese respondents answered “never”, which was also much higher than in other countries. Regular dental check­ups are considered to be less valuable in Japan as compared with other devel­ oped countries, with social and economic issues cited as primary reasons. Since improvements in oral health during childhood lead to improved oral health in adulthood, a major issue to be addressed in Japan is strategies to increase the rate of regular dental check­ups to the level seen in other developed countries.

Recently, several reports have indicated that the prevalence and severity of dental caries in Japanese children are showing decreasing trends. As a result, the chief complaint of patients being treated in the pediatric dental field has changed to such conditions as prevention of dental caries, malocclusion, dental trauma, and surgical treatment. In the present study, we analyzed information obtained at the first examination of new patients seen in the recent 4-year period, including chief complaint, sex,age, address, date, and reason for referral from another clinic. Those findings were compared with the records of patients treated in the prior 30-year period. The following results were obtained.

1.The chief complaint showed a tendency to be related to patient age.

2.Dental caries showed the highest prevalence of all chief complaints. However, most of those patients were referred from other special needs pediatric dentistry care institutions because of difficul ties with treating at a younger age.

3.As for the number of patients by age, the peak was 2-3 years old in records obtained from 1987 to 2004. Since 2004, another peak associated with malocclusion complaints at the age of 5-6 years appeared.

4.Chief complaints in regard to malocclusion and dental trauma showed increasing tendencies.

We concluded that an investigation of chief complaints among pediatric dentistry patients is very important to under recent trends regarding the oral conditions of children with special needs.

To evaluate uncooperative behavior by pediatric patients in dental clinical situations, multivariate analysis and other analyses of the relationships between patient age and expressions of uncooperative behavior were performed using criteria developedbyKurosuetal.(Kurosucriteria).Weexamined 224 healthy children between the ages of 3 and 6 years, and the following results were obtained.

1.Behaviors used as major explanatory variables identified by multiple regression analysis of the relationship between patient age and the Kurosu criteria were [Crying loudly], [Kicking legs], [Cry ing quietly], [Flailing hands], and [Shaking head].

2.In results of principal component analysis, the first principal component of 3-year-old patients was an index that reflected the effects of all Kurosu items and accounted for approximately 40% of the total. For the second principal component, the factors [hands] and [eyes, face] were considered to be contradictory indicators. The first principal component of the 4-year-old patients was an index that reflected the effects of all Kurosu items and accounted for about 34% of the total. For the second principal component, the factors [hands] and [eyes, face] were considered to be contradictory indicators. For the third component, the factors [trunk] and [eyes, face] were considered to be contradictory indicators. The first principal component of the 5-year-old patients was an index that reflected the effects of all Kurosu items and accounted for approximately 50% of the total. For the second principal component, the factors [trunk] and [leg] were considered to be in the same group,while [eyes, face], [leg], and [trunk] were considered to be contradictory indicators. The first principal component of the 6-year-old patients was an index that reflected the effects of all Kurosu items and accounted for approximately 40% of the total. For the second principal component, the factors [leg] and [trunk] were considered to be contradictory indicators.

Based on our results, we concluded that expressions of uncooperative behavior in child patients do not always lessen with increasing age and each behavior has different meanings dependent on age.

The incidence of supernumerary teeth in deciduous dentition is very low. In this case report, we present the treatment progress of a pediatric patient who had bilateral maxillary supernumerary deciduous teeth, which resembled upper lateral incisors. On follow-up visits, the patient was also found to have a fused tooth in the position of the upper left lateral incisor and an impacted supernumerary tooth on the palatal side of the upper right central incisor. A 1-year 10-month-old boy with 2 supernumerary teeth in the upper dental arch visited our clinic. Those were extracted at the age of 2 years 6 months because of crowding of the deciduous upper anterior teeth and premature contact with the lower incisors. During a periodic check-up for dental management of the patient, 2 more abnormal teeth were detected in mixed dentition ;a fused tooth in the upper left lateral incisor tooth position and an impacted supernumerary tooth on the palatal side of the upper right central incisor. The impacted supernumerary tooth was extracted at the age of 7 years 8 months, then the fused tooth was morphologically restored using composite resin. Space shortage was encountered for the upper anterior erupting teeth, thus the upper bilateral first premolars were extracted and an acceptable permanent dentition was attained.