The aim of this study was to derive the relationship between clinical symptoms and disc configuration on MR images of both sides with TMJ symptoms present or absent in juvenile patients with unilateral symptomatic temporomandibular disorders. The subjects were comprised of a study group of 80 juvenile patients with unilateral TMJ symptomatic temporomandibular disorders. The TMJ assessment consisted of the disc position, disc morphology and disc reduction at the maximum opening position using sagital MR images. Anterior disc displacement (ADD) was observed in 73 (91.3%) out of 80 patients consisting of 40 (50.0%) patients with bilateral ADD,31 (38.8%) patients with unilateral ADD on the side with the symptom and 2 (2.5%) patients with unilateral ADD on the side without the symptom. ADD was observed in 71 (88.8%) out of 80 TMJs on the side with the symptom and 42 (52.5%)out of 80 TMJs on the side without the symptom (p<0.01). Intermediate level of ADD was observed more on the side with the symptom of TMJ,43 (60.6%), than on the side without the symptom,23 (54.8%), (p< 0.05). Disc deformation was observed more on the side with symptom TMJ,44 (55%), than on the side without symptom 27 (33.8%) (p<0.05). ADD without reduction at the maximum opening position was observed more on the side with the symptom 41 (57.7%), than on the side without symptom 13 (31 %), of TMJ. Number of juvenile patients with bilateral ADD seemed to increase with their age. From this study it was clear that the grade of the ADD on the side with the symptom in juvenile patients with unilateral symptomatic disc disorders was worse than that of the ADD on the side without the symptom.
Moreover, these results implied that unilateral ADD may be one of the etiological factors of ADD on the contralateral side because of derangements of bilateral condylar movements.

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The anteroposterior position of the first molar on the maxilla may be determined by both genetic and environmental factors. The aim of this study was to identify quantitative trait loci (QTL) affecting the anteroposterior position of the first molar on the maxilla, using SMXA recombinant inbred (RI)strains of mice.
We measured the anteroposterior maxilla length between the incisor pore and the posterior border of the basisphenoid in 21 SMXA RI strains and its parental strains, SM/J and A/J. Also the length between the incisor pore and the upper first molar were measured in the same mice. The anteroposterior position of the first molar on the maxilla was evaluated by the value of the length between the incisor pore and the upper first molar divided by the maxilla length. For the trait, mean values of the substrains showed a continuous spectrum of distribution between 0.350 and 0.389, suggesting that the anteroposterior position of the first molar on the maxilla is controlled by multiple genes. In a genomewide linkage analysis, a high LOD score exceeding the suggestive threshold level was found at D 18Mit 7 on chromosome 18. These findings suggest that one of the genes controlling anteroposterior position of the first molar on the maxilla in mice is located in a distal region on chromosome 18.

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The Okayama University pediatric dental outpatient clinic started its services in April 1984. Since then, there have been changes in the demographics of patients and their dental needs. This study was therefore done to improve dental services for future patients. All dental records of patients coming for their initial visit in 2006 were compared with records of initial visit patients in 1993 and 1984. The following results were obtained:
1. There was a marked increase and decrease of patients coming for their initial visit since establishment of the clinic but this difference became negligible in recent years.
2. The chief complaints were mostly dental caries. However, there was a decrease in the number of dental caries and an increase in orthodontic problems and preventive dentistry or oral examination.
3. There was an increase in patients with systemic diseases and those who were physically and mentally handicapped.
4. The number of referrals accepted has increased.
5. There was a decrease in the number of patients in Okayama City, but an increase in patients in Okayama Prefecture and outside of the prefecture.
6. There was an increase of patients who had no experience of dental treatment prior to visiting our clinic. Seventy percent of the patients under six-years of age had no experience of dental treatment.

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Recent surveys on pediatric dentistry in university hospitals have revealed an increase in the number of patients under three years of age. It has thus been speculated that the overall prevalence of patients under three years old is on the rise. Ages under three years are a critical period for primary teeth eruption. However, the norm for dental treatment is three years of age or older, and the treatment of patients younger than this is considered difficult.
We conducted a dental survey of first-visit pat ients under three years of age who consulted the Department of Pediatric Dentistry, Suidobashi Hospital of Tokyo Dental College over a period of five years and six months from January 1999 to investigate chief complaints and reasons for visiting the hospital, and obtained the following results:
1) The minimum age of patients was 1 month. The peak age of patients was between a year and a half and two years of age.
2) The most common complaint was caries, followed by injury. The number of patients seeking caries treatment increased after a year and a half of age; injury was found in every age bracket except for those under six months old. Most cases with these and other chief complaints required diagnoses and treatment by pediatric dentists.
3) Approximately 30% of the patients was referred from general dental practitioners, and another 30%came for consultation without referral.
4) The main areas of residence comprised 23 wards in Tokyo.
The majority of the patients who visit the Departmen t of Pediatric Dentistry of university hospitals at an early age require diagnosis, treatment, and long-term maintenance by pediatric dentists. It is considered therefore that university hospitals play an important role in providing specialized dental treatment for those patients.

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The purpose of this study was to detect the factors which would affect the period of apical bather formation of apexification in immature permanent teeth.
The results of this investigation were as follows.
1) The period of apical barrier formation was longer in incior teeth than in molar teeth.
2) The shorter the period from the beginning of treatment to the filling of root canals with paste agent was, the longer the period of apical barrier formation was.
3) The shorter the exchanging period of the filling of root canals with paste agent was, the faster the period of apical barrier formation was.

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The recent decline in birthrate, The decrease of caries in childhood, and the increase in the number of dental offices has led to changes in how local clinicians handle child patient referrals. We carried out a survey to identify the actual situation regarding referrals by general dental practitioners so that channels of communication and cooperation could be established between these local clinics and our university dental hospital ensuring that our child patients continue to receive proper treatment and regular dental checkups. The referral letters and dental records of 620 child patients who had been referred to our dental hospital from 2003-2006 were surveyed and the results were as follows.1. The majority of these children were 9 years of age or younger with the 3-4 yea r-olds comprising the age group most referred.2. The major reason for referrals of children aged 3 or younger was dental caries and injuries, while for children aged 6 and older, caries was the primary reason for referral. Results also showed that the older the children, the greater the number of inquiries concerning tooth eruption and occlusion, and the fewer the number of injuries.3. About 20% of the referrals was because of patient odontophobia or uncooperative behavior on the part of the patient; of these cases 92.4% were treated in our department as outpatients and 4.9%were treated under general anesthesia. It is important that our de partment and local clinicians exchange information and opinions in an effort to meet the needs of our child patients by improving post-treatment management and the handling of special cases.

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Dens invaginatus is called dens in dente, the developed tooth being abnormal and rarely observed in the mandibular teeth, but dens invaginatus has been reported in some mandibular incisors and premolars. A 12 year 7 month old girl visited our clinic with a complaint of gingival swelling in the region of her mandibular right premolar. Periapical radiographs, CT radiographs and clinical examination revealed dens invaginatus present in the mandibular right second premolar, as well as periradicular radiolucency. The tooth was treated with endodontic instrumentation and obturation, followed by coronal restoration using a glass ionomer base, and an occlusal composite resin. Due to their abnormal anatomical configuration, canal accessibility of invaginated teeth is difficult technically. It is important to prevent the bacterial infection of the dental pulp by the sealant, to do follow-up observations, and to render endodontic therapy as early as possible at the time of the pulpal infection.

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Fused or attached teeth in primary dentition are observed frequently in pediatric dentistry. Most cases of fused or attached teeth appear in the lower central and lateral incisor, or lateral incisor and canine.
We report on two cases of fused or attached primary molar in the patients with cleft lip, alveolus and palate (CLP). The first case showed that lower primary first molar and supernumerary tooth were attached together. Tooth germ of the second premolar was not identified by X-ray examination. The second one showed that the lower primary first and second molar were fused. The tooth germ of the lower second premolar was not identified. These results indicate that evaluation of attached or fused teeth in the region of the primary molar is required for dealing with the occlusion. Furthermore, the prevalence of dental caries is higher in those teeth compared with normal ones, because the attached or fused tooth has an accessory fissure and/or enamel hypoplasia.
We need to perform a careful and periodical examination to give occlusion and oral hygiene instruction to prevent caries for patients with CLP.

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The purpose of this study was to evaluate the relationsh ip between the duration of decalcification and the number of decayed teeth at one year after the first application of the software which made the caries prediction. We examined a total number of 158 children (74 males and 84 females) aged between three and fourteen with an average age of six. The following results were obtained. The number of decayed teeth for one year showed a significan tly positive correlation with the duration of decalcification by using Spearman's rank correlation coefficient. The duration of decalcification (19.3%) in the caries-free group was significantly lower than that (23.6%) in the caries group. Based on these resu lts, the duration of decalcification in order to keep the caries-free condition for one year might be suggested to be less than 19%.

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There is a strong presumption that playing a wind instrument would have a profound impact on the maxillofacial morphology and oral functions of players, especially when they are physically in the period of growth and development. We encountered a case of myofunctional disorders involving a temporomandibular joint and aggravated occlusion in a growing individual with malocclusion by nature. She had been practicing hard on a wind instrument for the preceding 14 months. We thought that it would be worthwhile to explore the relationship between malocclusion and playing the wind instrument from the standpoint of dentistry as well as of medicine. The purpose of this study was to shed light on the association between the playing of the wind instrument during adolescence and developmental changes in the shape of jaws and face in terms of morphology and masticatory function.
The subject of the study was a 13 year,5 month old girl who was enthusiastic abou t practicing the baritone saxophone. Upon examination, there was a proclination of the maxillary anterior teeth, a retroclination of the mandibular anterior teeth, a steep mandibular plane, reduction in height of the mandibular ramus, a recess of the mental foramen, and anteriorly upward-tipped palatal plane.
In conclusion, our study findings suggested that before starting to play a wind in strument, growing young people with malocclusion should receive treatment to correct the deviation of the upper and lower jaws without delay and make a wise selection of an instrument.

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