Teeth, maxilla and mandible are complex structures and their sizes can be determined by genetic and environmental factors. The purpose of this study was to investigate the relationship between genetic factors in the growth of crowns and jaws in inbred mice. We measured the mesiodistal crown diameters of the first molars, anteroposterior mandible length between menton to gonion and anteroposterior maxilla length between the anterior border of the incisor pore and the posterior border of the basisphenoid in 21 SMXA recombinant inbred (RI) strains and their parental strains, SM/J and A/J.
The results obtained were as follows.
1. Continuous distribution patterns of both crown diameters in the first molars and lengths of jaws in SMXA RI strains suggest that sizes of the crowns and jaws are not determined by a simple Mendelian inheritance and are controlled by multiple genes.
2. Crown diameters in the first molars and lengths of jaws in SMXA RI strains may be strictly controlled by genetic factors rather than environmental factors.
3. It is conceivable that SM/J and A/J-derived alleles include both increasing and decreasing effects on the growth of the crowns and jaws, and that the sizes of the crowns and jaws in SMXA RI strains are determined by a combination of SM/J and A/J-derived alleles.
4. A correlation of crown diameters between the upper and the lower first molars suggests that the same gene effects influence crown growths of both the upper and the lower first molars.
5. As maxilla and mandible lengths have a mutual relationship, the same gene effects may influence the growth of both the maxilla and mandible.
6. There was no correlation between the maxilla length and crown diameters of the upper first molar. There was also no correlation between the mandible length and crown diameters of the lower first molar. These findings suggest that crown and jaw growths are genetically independent, and that different gene effects strongly influence crown and jaw sizes.

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Treatment for pediatric leukemia may have adverse effects on developing teeth. We studied the dental development, using panoramic radiographs, of 31 patients younger than age 12 diagnosed as having leukemia, and investigated the relationship between the permanent tooth formation stages and treatment for leukemia. The disturbances in tooth development were classified into three major groups such as agenesis, microdontia and arrested root development. Further, arrested root development was classified into five varieties according to root morphology and shortening degree.
1. As for the relationship between the dental developmental disturbances by chemotherapy and the tooth formation, stage, microdontia was observed among 95.5% of the cases in the stage of “before the start of calcification. ”In addition, U 2-type arrested root development was observed in approximately 80% in the stage of “crown complete. ”
2. As for the relationship between the dental developmental disturbances by hematopoietic stem cell transplantation and the tooth formation stage, in the stage of “before the start of calcification, ” agenesis was observed in 83.3% of the cases, and microdontia was observed in 16.7% of the cases. Microdontia was observed in 90% or more of the cases in the stage of “cusp formation. ” As for arrested root development, it was observed in 100% of the cases in some root morphology from the stage of “crown 3/4 complete” to “root length 1/2. ” V 1-type arrested root development was observed in 76.5% of the cases in the stage of “crown 3/4 complete”; V 2-type arrested root development was observed in 45.9% of the cases in the stage of “crown complete”; Y-type arrested root development was observed in 31.3% of the cases in the stage of “root length 1/4”; U 1-type arrested root development was observed in 33.3% of the cases in the stage of “crown complete”; U 2-type arrested root development was observed in 68.2% of the cases in the stage of “root length 3/4. ”
3. Dental developmental disturbances were observed by radiographs at four years after the treatment.

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The purpose of the present study was to investigate craniofacial morphological deviations in cases with mandibular arch crowding and their relationship to discrepancies in the permanent dentition, and to establish treatment objectives for crowding in the mixed dentition. The subjects comprised 20 females with mandibular arch crowding at Hellman's dental age IVA (the crowding group), who all had Angle class I occlusion and existing mandibular third molars. The mean age of the crowding group was 17 years and 8 months. The materials consisted of posteroanterior, lateral and forty-five degree oblique cephalograms, and mandibular models of the crowding group. The measurements for craniofacial morphological deviations, and anterior, posterior and total discrepancies were made in the crowding group. Statistical analyses were made for these deviations compared with the previous reported Japaneses norms, and their correlation to discrepancies investigated.
The characteristic features in the crowding group were the smaller cranial base and gonial angles, the shorter ramus height, the anteriorly and upward rotationed mandibule, the mesial inclination of the canines, first and second premolars and first molars, and the infraversion of the canines, and first and second premolars. The anterior discrepancy showed a significant correlation with the mesial inclination and infraversion of canines, and the distal inclination of second molars. The posterior discrepancy showed a significant correlation with the distal inclination of second premolars and first molars. The interception of these morphogical deviations was the objective of the treatment for mandibular arch crowding in the mixed dentition.

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The purpose of this study was to evaluate the tensile bond strength of commercially available fissure sealants to the bovine enamel. Moreover, we evaluated the influence of the combination of fissure sealant (Resin-based or Glass ionomer) and the enamel surface pretreatment reagents (acid etching or conditioner)
The results were as follows:
1. FE-SEM revealed that the degree of decalcification using phosphoric acid etching was greater than that using the conditioner treatment.
2.The tensile bond strengths of resin-based sealant to bovine enamel was significantly higher than that of glass ionomer sealant when both sealants were used according to the instruction of the manufactuer.
3. The tensile bond strength was influenced by a combination of fissure sealants and the enamel surface pretreatment reagents. The bond strength of the resin-based sealant was influenced more by the difference of pretreatment reagents than that of the glass iomomer.
4. When resin-based sealant was applied to the enamel, the mechanical anchorage was a dominant factor for the bond strength to enamel etched with phosphoric acid, resulting in higher bond strength. On the other hand, when glass ionomer sealant was applied to the enamel, the mechanical factor was not a dominant factor for the bond strength due to the lower mechanical properties of glass ionomer selant.

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Neuropeptide Y (NPY) is an orexigenic peptide and the arcuate nucleus (ARC) is the primary site of NPY synthesis in the hypothalamus. In adult rats, arcuate NPY mRNA increases during periods of food deprivation and it returns to the basal levels when the rats are fed again. Little is known, however, about relationship between the expression of NPY mRNA in the brain and feeding behavior during the early developmental stage. In the present study, expression of NPY mRNA in the ARC and lower brainstem was examined in neonatal rats under conditions of satiation and fasting by in situ hybridization.
Neonates of postnatal day (P) 2,7 and 10 were classified into three groups; "control" pups were nursed by the mothers until being sacrificed, and "fasting" pups were sacrificed after maternal deprivation for 18 h (P 2) or 30 h (P 7,10), and "refed" pups were separated from the mothers for 12 h (P 2) or 24 h (P 7,10) and then nursed for 6 h before being sacrificed. Fasting pups showed significantly higher NPY mRNA levels in the middle of the ARC than the controls at all of the ages examined, and refed pups showed middle levels of NPY mRNA between the control and fasting pups. NPY mRNA levels in the nucleus of the solitary tract (NST) increased in fasting pups on P 2, but did not show change on P 7 and 10.
These results indicate that NPY neurons in the ARC respond to fasting at all the ages examined (P 2,7,10), while those in the NST respond to fasting only on P 2. There may be a critical period when NPY neurons in the NST participate in feeding behavior of neonatal rats.

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Much epidemiological research has been conducted on childhood dental fear and anxiety, but it is difficult to compare these comprehensively due to several parameters such as methodological or criterion variables among the populations surveyed. To enable comparisons with other countries, in the present study the Dental Subscale of Children's Fear Survey Schedule (the CFSS-DS) was used, a well-known instrument showing good reliability and validity and used in several countries in the study of childhood dental fear. This study described the prevalence of dental fear in Japanese, and examined its relationship with trait anxiety and willingness to visit a dentist. The following results were obtained.
1) The Japanese version of CFSS-DS showed high reliability and validity.
2) Twenty percent of Japanese school children were dentally fearful. Girls were more likely to report to have dental fear than boys.
3) Children who had never visited a dentist were more likely to report to have higher dental fear than those who had visited.
4) The more fear the children had, the higher trait anxiety they had.
5) Japanese school children had relatively higher dental fear than Scandinavian children, but lower fear than that of children in the US, Singapore and China.

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The pattern of appearance of congenitally missing teeth in the oligodontia was studied. The materials consisted of panoramic radiograms taken from 12 patients who were missing more than three permanent teeth congenitally except third molars without any systemic disease in particular. We added up every missing permanent tooth on both sides of 12 patients and designated them as the total number of missing teeth. We discussed the degree of accordance between the amount of the total numbers of missing teeth of the permanent successors from the central incisor to the second premolar and Fujita's Terminal reduction theory which had explained the human reduction pattern in teeth theoretically.
The results were as follows:
1. In the upper arch, in no case was the central incisor missing congenitally and the total numbers of missing teeth increased in order as the teeth went in a distal direction.
2. In the lower arch, in no case was the canine missing and the total numbers of missing teeth increased in order from the canine as the teeth went in both mesial and distal direction.
3. These appearance patterns of the missing teeth did not necessarily correspond to Fujita's Terminal reduction theory which presupposes that the upper and the lower arch are considered in series with the lower arch ahead, both the upper central incisor and the upper canine being the Key Teeth.
4. Assuming that the upper and the lower arch were to be independent again and the Key Teeth were the upper central incisor and the lower canine, there was no discrepancy between the result of this study and the main part of Fujita's Terminal reduction theory that the reduction would occur from the terminal sides of each tooth group.

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We investigated the regulatory effects of the macrophage migration inhibitory factor (MIF) on osteoclast formation. MIF plays an important role not only in the immune system, but also in cell proliferation and differentiation in a variety of organs. MC 3 T 3-E 1 cells and mouse bone marrow cells were cocultured, and formation of osteoclastic multinuclear cells was examined. MIF reduced the number of multinuclear cells differentiating from bone marrow cells. It was not due to either impairment of receptor activator of nuclear factor-kappa B ligand (RANKL) mRNA expression or activation of osteoprotegerin production in MC 3 T 3-E 1 cells. MIF almost completely suppressed the formation of mature osteoclasts while the total number of the nuclei of osteoclastic cells per well was unaffected. These results suggest that MIF inhibits formation of mature osteoclasts by preventing the multinucleation process.

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In this study, we aimed at establishing broader assessments of development of feeding functions with respect to behavioral development. We examined the relationship with the results of the evaluation of development by means of observation of feeding actions and behavior for weaning subjects. We obtained the following results:
1. Concerning the divided weaning periods based on "the revised edition of the basics of weaning"and the assessment of feeding functions, there were more infants observed in the middle-to-latter period of weaning who had a high evaluation of feeding functions of the Chronological ages. Regarding the Developmental ages and the weaning period, in the latter period of weaning, many infants were observed with a higher the Developmental ages than the month of after-birth seen in the division of weaning.
2. We paid attention to the relationship between the weaning periods which were divided in accordance with the development of feeding functions and the Chronological ages, as well as the Developmental ages of the developmental assessment. In each period, the Chronological ages was higher than the Developmental ages. The Developmental ages in feeding regions was found to be lower than those in other regions (action, searching/manipulation, society) in all weaning periods, but no significant differences were found.
3. We examined the relationship between the indexes of each feeding function, the Chronological ages and the Developmental ages. The Chronological ages was strongly related to the Developmental ages in many indexes of each weaning period. However, in the index based on the traction of angle of mouth and tongue movement until the middle period of weaning, the Developmental ages and the Chronological ages showed a weak connection.

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Treatment using the MUH Shield (YC 3 Shield) appliance and that using the chin cap were evaluated. Based on lateral cephalalometric radiographical analysis, changes in craniofacial morphology and tongue position after treatment of deciduous anterior cross bite were compared among the 12 patients in the MUH Shield (YC 3 Shield) group and the 9 patients in the chin cap group, for whom the over jet relationship had inrproved. The following results were obtained.
1. The MUH Shield (YC 3 Shield) group showed labial inclination of the maxillary anterior teeth, flattened occlusal plane, and posteriorly changed, and elevated tongue position.
2. The chin cap group showed a retruded position of the mandibular bone, decreases in mandibular angle, and a posteriorly changed tongue position.
3. It was speculated that functional changes when using the MUH Shield (YC 3 Shield) appliance influenced the skeletal pattern in terms of function during the period of active skeletal growth.

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In laboratory mice, cleft lip, cleft lip with palate and cleft palate are generally very rare. However, the cleft lip with or without cleft palate occurred spontaneously at higher frequencies in one family of inbred mouse “A” strains. In addition, it has been known that cleft palate can be induced in fetal mice by injection of cortisone during a sensitive period of gestation. Recently, the “A” strains of mice have been utilized extensively as models to study the genetic factors and the processes involved in clefting of the lip and palate. Of the “A” substrains, the A/WySn mouse was utilized in this study to investigate the frequency of spontaneous cleft lip with or without cleft palate and cleft palate, and detect their susceptibility to this teratogenic effect that cortisone-induced orofacial clefts. Another was used to compare the differences in incidence between the A/WySn and C 3 H/He strains. Pregnant mice were injected on days 11 through 14 of gestation with 100 mg of cortisone per kg of body weight. As a control group the pregnant mice were not treated with the drugs mentioned above. The frequency of each cleft was observed among embryos that attained at least Day 18 of development. In the control group, A/WySn was found to have a frequency of spontaneous cleft lip and cleft lip with palate being 3.7% (9/241) and 10.8% (26/241), respectively, but cleft was not found in C 3 H/He strains. Further, the incidence of cortisone-induced cleft palate in A/WySn for 40.6% (65/160) was significantly higher than 16.7% (8/48) in C 3 H/He. The mean living fetuses showed significant decreases in the A/WySn, showing no appreciable decreases in C 3 H/He when the pregnant mice were treated with cortisone, indicating the susceptibility to the teratogenic effect of cortisone in A/WySn. The significantly different frequency occurring the orofacial clefts between A/WySn and C 3 H/He suggested however that this may apply to genetic research for human congenital cleft lip, cleft lip with palate and cleft palate as the animal model thought genetic crosses between the two strains of mice.

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Nursing bottle caries is a type of rampant dental caries associated with prolonged bottle-feeding. Mutans streptococci have been thought as the principal microorganisms that cause coronal caries in humans. They settle in the mouth after the teeth are erupted because they primarily colonize tooth surfaces by utilizing self-synthesized water-insoluble glucan from sucrose. However, the number of mutans streptococci detected in milk-fed infants is very small. Mutans streptococci are not able to produce water-insoluble extracellular glucan from lactose that is a dominant saccharide in breast milk or in commercially available powder milk provided for infant formula. Moreover, some fractions of milk protein prevent mutans streptococci from adhering to the tooth surface. These imply that some other microorganisms than mutans streptococci may cause dental caries in the milk-fed infants.
On the other hand, lactobacilli are detectable in the mouths of infants. The detection rate rises from 30% at 4 months of age to more than half at 12 months of age. They are also known to be the most acidgenic and aciduric bacteria of human oral florae. They seem, however, unlikely to be a member of human dental plaque.
Hypothesizing that there must be some lactobacilli that show a certain affinity to milk pellicle on teeth in the mouths of infants, adhesion of lactobacillus collected from the saliva of infants to a few experimental pellicles derived from skim milk and/or human saliva formed on hydroxyapatite beads (HA) in places on human teeth were examined in this study.
HA was equilibrated in a phosphate buffered saline (PBS) and incubated either with 10% skim milk for preparing the milk pellicle (milk-HA) or with whole human decomplemented filtered saliva (DFS) from an adult subject for preparing the salivary pellicle (s-HA). Some aliquots of s-HA were further soaked in the skim milk for preparing the saliva-milk mixed pellicle (mix-HA). Bacterial cells were radiolabeled during culture, washed in PBS, suspended in DFS and challenged to the pellicles at a turbidity of OD_550nm=0.1.
Mann-Whitney's U-test verified that only one out of 7 strains tested, Lactobacillus paracasei JCM 1133, adhered by itself to milk-HA and mix-HA (P<0.05). This strain was revealed to adhere to s-HA (P<0.05), too. In addition, although the amount was varied, it adhered to s-HA (P<0.05) prepared with DFS respectively derived from subjects including milk-fed infants and other adults.
It is therefore suggested that when a lactobacillus like JCM 1133 is introduced into a human mouth, it may be able to adhere to smooth surfaces of teeth, irrespective of milk consumption and age of the subject because the bacterium possesses a certain affinity to the saliva-milk mixed pellicle and salivary pellicle formed on the tooth surfaces.

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Inconsistent results have been reported on the chronological changes in the size of the permanent teeth crown and its actual condition is still not clear. The change in the tooth crown size was investigated between the present and twenty years past by measuring the mesio-distal and bucco-lingual width of central incisors and first permanent molars representing successor and predecessor respectively using plaster models of children with mixed dentition. The subjects were fifty-five children (twenty-eight males, twenty-seven females) and fifty-nine children (thirty males, twenty-nine females)who visited the pediatric dentistry clinic at Iwate Medical University from 1995 to 2000 and from 1975 to 1980, respectively. The following results were obtained.
1. The mesio-distal width of the first permanent molars of the present male children was significantly smaller than twenty years ago. As for the central incisor, the maxillary of the males was larger while mandible of the males, the maxillary and mandible of the females were smaller, although without statistically significant difference.
2. The bucco-lingual width of the first permanent molar showed no significant change when compared with twenty years ago in both male and female children. That of the male central incisor was significantly larger.
3. Although central incisors and first permanent molars were used for measuring typical permanent teeth, no consistent clear tendency was detected. Farther investigations on other kinds of permanent teeth are required.

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There are various methods in the medical treatment of hemangioma. Particularly hemangioma of the face requires medical treatment with the aesthetic aspect taken into consideration.
A 1-month-old girl with a red spot lesion in the upper lip was referred to the Chiba Children's Hospital. At first, it appeared as 3 pinhead-sized spots, and the clinical diagnosis made was a strawberry mark. Observations on the changes in the lesion were continued. The lesion increased in size and occupied two thirds of the lip at 8 months of age. She was histologically diagnosed as having capillary hemangioma of the upper lip at 8 months of age. As the size of the tumor increased, intralesional injection of absolute ethanol was planned and the endpoint of the treatment was set at blanching and shrinkage of the hemangioma. Ethanol at a dose of 0.4 ml was injected into the tumor at 11 months of age.
Ethanol at a dose of 0.7 ml was used at 1 year and 2 months of age. Afterwards, the injection of ethanol was given 4times with doses ranging from 1.1 to 2 ml. With these treatments, the tumor was blanched and shrunk gradually, but a slight bulge of the upper lip remained. Plastic surgery of the upper lip was performed at 3 years and 8 months of age. Therefore, with this operation, the lip became symmetrical and there was no paresthesia of the lip. Presently, at 11 years of age, no relapse was found.
Intralesional injection of absolute ethanol is useful in the treatment of hemangioma.

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Williams syndrome commonly includes such symptoms, as growth abnormalities, mental retardation, and cardiovascular anomalies. Dental care for a Japanese boy with Williams syndrome was performed starting at the age of 4 years and 7 months. In this patient, low body weight and height, slight mental retardation, disruption in walking, as well as an atrial septal defect that closed naturally at the age of 2 years were observed as the general symptoms. Oral examination revealed a large number of caries and anterior crossbite. Radiographic examination revealed some question as to the abnormal form of the permanent incisors.
Although he cried and struggled at the beginning of the caries treatment, his cooperation improved gradually. Periodical oral care for this patient has been rendered for the purpose of maintaining good oral health.
Caries treatment of children with Williams syndrome is difficult and requires care because of the symptoms associated with the syndrome, such as mental retardation and cardiovascular anomalies. It is therefore important for patients with Willams syndrome that the oral care is rendered periodically in order to maintain good oral health.

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