Over the past 30 years, bisphosphonates (BPs) have been used for prevention and treatment of bone diseases characterized by bone fragility, such as osteoporosis. Recently, an increased risk of bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been identified in patients with longterm BP administration, and no effective therapy has been established for this severe and extremely refractory progressive condition. We constructed a mouse model of BRONJ-like disease that manifests the major clinical and radiographic findings of the disease seen in humans, including characteristic features of delayed healing displayed orally as an open alveolar socket, exposed necrotic bone, increased inflammatory infiltrates, and radiopaque alveolar bone in the jaw. The present findings show that an alteration in the balance between Treg/Th17 allows development of BRONJ.

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Caries is the most commonly encountered chronic multifactorial disease in the world, though little is known about genetic factors influencing susceptibility. Our previous genome-wide linkage scan identified 5 loci related to caries susceptibility ; 5q13.3, 13 q 31.1, 14q11.2, 14q24.3, and Xq27. In the present study, fine mapping of the 5q13.3 locus was reviewed. Using single nucleotide polymorphism (SNP) genotyping, 477 subjects from 72 pedigrees with similar cultural and behavioral habits living in the Philippines were studied. For replication purposes, a total of 1464 independent subjects from 5 different populations were analyzed based on their caries experience. Statistically significant associations were found between caries experience and 3 genes spanning 5q13.3, and those results were replicated in some of the populations studied. In addition, SNP markers were genotyped in selected genes that influence enamel formation in the same populations. The most expressive association between caries and genotypes was for a marker in AMELX. Our results suggest that genes in 5q13.3 and AMELX may be related to caries susceptibility.

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Cleft lip and/or cleft palate (CLP), a major craniofacial structural birth defect occurring in humans,has a prevalence of rate of 0.18−0.20% in newborns in Japan. Patients with CLP require complex interdisciplinary care, including nursing, plastic surgery, maxillofacial surgery, otolaryngology, speech therapy, audiology, psychological and genetic counseling, orthodontics, and dental treatment, as well as others. For an effective clinical approach, clinical specialists must communicate as team members to provide CLP treatment. A pediatric dentist is an important member of the CLP treatment team and can organize appropriate management, referral, and follow-up examinations for oral care throughout the life of the patient. On the other hand, a basic science approach is also important to evaluate CLP occurrence and investigate means of prevention. We have focused on soft palate development using mice. Velopharyngeal insufficiency causes severe functional difficulties in swallowing and speech,which are deeply associated with quality of life for CLP patients. Histological analysis has shown that cranial neural crest cells comprise the palatal mesenchyme found throughout the anterior and posterior axis of the palate. During soft palate development, neural crest cells express periostin in the posterior region. Furthermore, periostin expression is regulated by TGF-β signaling. Our results suggest that periostin, an extracellular matrix, plays an important role in palatal muscle development during palatogenesis via TGF-β signaling. Additional research is needed to elucidate the specificity of soft palate development using a mouse model. Better understanding of the mechanism of soft palate development will provide new therapeutic approaches for CLP patients.

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We clinically investigated 40 teeth in 31 patients (mean age 7 years 6 months) requiring tooth extraction and performed cone beam computed tomography (CBCT) to obtain a definitive diagnosis over a 5-month period from October 2013 through March 2014 at our specialized pediatric dental clinics. The results indicated that maxillary anterior supernumerary teeth are more common in males,with a male to female ratio of 7 : 2, while the direction of eruption was normal for 17 and inverted for 23 teeth. In addition, 22 patients had 1 and 9 had 2 impacted supernumerary teeth. Based on the distance from the inferior margin of the bottom of the nasal cavity to the alveolar crest in panoramic radiographs, we evaluated the position of impacted supernumerary teeth by classifying vertical depth (type I−III), which showed that 5, 26, and 9 teeth were type I, II, and III, respectively. The 3-dimensional positional depth of the impacted supernumerary teeth was also investigated by classifying their position as 1, 2, or 3 from the palatine bone to the alveolar bone in sagittal CBCT images. Those results indicated that 8, 23, and 9 teeth were in position 1, 2, and 3, respectively.Together, our results demonstrated that the positions of supernumerary teeth shown by CBCT coincided with those shown by panoramic radiography in 92.5% of the examined cases. Prior to extraction of a maxillary anterior supernumerary tooth, depth classification based on panoramic radiography findings exhibited a statistically significant correlation even when converted to a three-dimensional positional relationship, suggesting their use as diagnostic criteria for indication of extraction.

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Digital panoramic radiography with tomosynthesis can be used to measure the distance between any 2 points with spatially oriented panoramic planar imaging technology. We determined measurement values (MVs) for mesio-distal crown diameter on tomosynthesis panoramic radiograph (TSPX) images and compared them with standard values (SVs) obtained from plaster models of children who had eruption of 4 permanent lower front teeth and persistence of deciduous lower lateral dentition. In addition, we determined the correction factor (α ) for each tooth type by dividing SV by MV and analyzed measurement accuracy. Moreover, we calculated the mesio-distal crown diameters of unerupted permanent lateral dentition predicted by multiplying α of the associated primary teeth, and compared those with predicted values obtained with the regression equation of Ono and prediction table of Moyers.The MV of the mesio-distal crown diameter of the lower deciduous molars showed a tendency to be greater, while that of the mesio-distal crown diameter of lower deciduous canine and permanent front teeth tended to be reduced in the TSPX findings. The mesio-distal crown diameter of permanent lateral dentition determined by TSPX was consistent with values determined by use of the regression equation of Ono and 50th percentile prediction values from the prediction table of Moyers, except for a female case of the left mandible. Therefore, space analysis using TSPX may be more effective than the regression equation of Ono and prediction table of Moyers, because dispersion of personal data can be expressed.

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In this study, we aimed to develop an effective method for remineralization (REM) of enamel with incipient dental caries. The effects of phosphoryl oligosaccharide calcium (POs-Ca) with various fluorides on REM was evaluated by quantitative light-induced fluorescence (QLF) and transverse microradiography (TMR). Bovine enamel surfaces (1×5 mm) were covered with clear nail varnish and then demineralized using a two-layer method with an 8% carboxymethyl cellulose gel and 0.1 M lactate buffer (pH 4.5) at 37℃for 2 weeks, then immersed in PBS for 1 day. After removing the varnish with acetone, fluorescence loss［ΔF(%)］，ΔQ(％・mm²), and white spot demineralized area size［WS area (mm²)］of the enamel samples were determined by QLF. As a test of experimental surfaces, the enamel surfaces were again covered with the same varnish, then remineralized at 37℃under various conditions in the presence of POs-Ca (0.48%), 1.2 ppmF of green tea fluorine, acidulated phosphate fluoride (APF), or NaF. REM was determined by QLF, then mineral loss (ΔZ) and lesion depth (ld) of the remineralized samples were determined by TMR. After a 1-week REM period, ΔΔF, ΔΔQ, and ΔWS area were determined by QLF. The REM of the POs-Ca group (CP group), CP＋green tea F group (CPF group), CP＋APF group (CPAPF group), and CP＋NaF group (CPNaF group) showed them to be significantly more effective than the control group (C group : Ca/P ratio＝0.4). The REM rate using ΔZ and ld of each REM group was determined by TMR. The REM rates of the control group, CPF group, CPAPF group, and CPNaF group were 12.22±5.37%, 58.10±10.87%, 56.54±8.46% and 48.60±12.75%, respectively. When effects of various fluorides on REM were compared,green tea F tended to promote REM more effectively than the others. Furthermore, promotion of REM by POs-Ca was significantly reinforced as compared to the control by addition of fluorides.

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To determine the cause of fear and worry regarding dental treatment in children, which can be factors for stress during procedures, we measured α -amylase using a simplified chair-side indicator in patient saliva samples obtained before and after treatment in 84 children aged 3−12 years (45 boys, 39 girls). The relationships between measured values and various parameters were examined, with the following results obtained.1.There were differences among individuals as well as wide variations in amylase levels in saliva before and after treatment. However, the value declined after treatment in many cases.2.Although no significant differences related to age were observed in regard to amylase level, that rose after treatment in many patients aged 6 to 12 years old.3.When analyzed by time of day, the percentage of cases with an elevated level after treatment was higher in the afternoon than in the morning, while that of cases with a reduced level was significantly higher in the morning.4.There were scant variations in amylase level when analyzed based on hour or treatment protocol.5.Use of local anesthesia had no significant effect on variations in amylase level.6.Patient characteristics had no significant correlations with amylase levels. However, there were slightly fewer patients with a quiet character who showed an elevated level after treatment as compared to those classified as active or average, while the number of quiet patients with a reduced level was somewhat greater as compared to the other types.Based on our results, we propose that treatment of child patients should be performed with appropriate consideration regarding time of day, use of local anesthesia, age, and personal characteristics. Our findings may also be useful for development of future dental procedures.

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For further improvement in hospital-clinic cooperation, we conducted a survey of new patients (n＝952 ; 550 boys, 402 girls) who visited the outpatient clinic of the Department of Pediatric Dentistry,School of Dentistry, Showa University from January 1, 2012 to December 31, 2013 and brought treatment information reports or referrals from dental clinics or general hospitals. The following results were obtained.1.The most common age of the referred patients was 7 years and patients aged 0 to 8 years accounted for approximately 80% of the total.2.Most of the referring institutions were dental clinics, which accounted for more than 90%.3.Dental caries was most common reason for referral for patients 0 to 6 years old, while tooth eruption anomaly was the most common for those aged 7 years and over.4.By area, dental caries referrals most commonly came from neighboring areas, while tooth eruption anomaly referrals commonly came from distant areas. No difference was recognized for dental trauma in regard to the area of referral.5.As for the age of the referred patients by area, no difference was seen for patients 12 years of age and under, while a significant difference was recognized for patients 13 years old and over.In contrast to our previous report, we found relationships between age of the referred patients and area, as well as reason for referral. Based on our findings, we considered that a quick understanding of the situation for which our department is needed as well as close cooperation with neighboring dentists are important factors for pediatric dentistry provided by our dental university.

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Various studies of lip closure in children have recently been reported, though few have given attention to child patients with open bite. We investigated 15 children with normal occlusion and 15 with open bite ranging in age from 8 to 11 years old who were treated at Kyushu Dental College. The purpose of this study was to examine lip closing force in children with open bite.We determined lip closure force using a multidirectional lip closing force measurement system and tongue pressure with a simple tongue pressure measuring assembly, and also examined hearing ability. Our results showed that lip closing force from the lower jaw was significantly greater than that from the upper jaw in both the normal occlusion and open bite groups.In a review of previous reports, muscle pressure from the lower lip was shown to be significantly greater than that from the upper lip, and children with open bite and puckered lips showed the same results as found in the present study. We consider that movement of neighboring soft tissues during lip closure in children with open bite is similar to that in those with normal occlusion.Results of tongue pressure measurements revealed no significant difference between children with normal and open bite. In regard to tongue elevation to the palate, our results suggest that children with an open bite have similar characteristics as those with normal occlusion.In addition, questionnaire findings showed that children with an open bite have easier mouth opening and tend to breathe through the nose. There are various causes of open bite development, and we intend to investigate its association between mouth breathing and open bite in a future study.

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Cleft lip and palate (CLP) is the most frequent cleft malformation seen in the maxillofacial region and morphological changes have been observed when evaluating treatment. However, few studies have reported regarding changes in oral function in affected patients. We investigated changes in physiological characteristics of sucking function along with perioral muscle activity and sucking pressure in infants with CLP.Twelve infants with unilateral CLP underwent a cheiloplasty procedure at the center of the cleft lip and palate at Fujita Health University Hospital. Measurements were performed before, and 1 week and 3 months after the cheiloplasty. Electromyogram (EMG) findings from the bilateral temporal (L-R, TM) and masseter (L-R, MM) muscles, as well as the orbicularis oris (OM) of the healthy side and the suprahyoid (SM) muscles were recorded. Values for sucking pressure and EMG findings obtained from healthy infants at the age of 3 months were used as a control.We found that both sucking cycle time and negative pressure duration during sucking were significantly longer following the operation. Activities on both sides of the TM, OM, and for total muscle were significantly increased after the operation, while sucking pressure was also significantly increased at 3 months. A comparison of CLP infants at 3 months after the cheiloplasty with the control group showed that SM activity was significantly decreased in the former.In conclusion, the duration of negative pressure in a sucking cycle increased following cheiloplasty procedures, which seemed to be effective for formation of negative intraoral pressure. However, EMG activity of the SM in the CLP remained low after the cheiloplasty, indicating that tongue movement during sucking was weaker than that in full-term normal infants.

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There are many reports regarding the influence of tracheal intubation on the oral cavity in very low and extremely low birth weight infants, though none from Japan. Furthermore, the long-term impact of tracheal intubation on dentition during infancy is rarely reported, due to rapid growth and development that occur prior to the first visit to a dental clinic.We treated a child with incomplete eruption, enamel hypoplasia, and crossbite in the upper anterior deciduous teeth that appeared to be due to the influence of tracheal intubation. The patient, an extremely low birth weight infant who had undergone tracheal intubation for a period of 3 months, was 2 years 3 months old at the time of the initial examination. At that time, the upper left deciduous central incisor, deciduous lateral incisor, and deciduous canine were found to be incompletely erupted,while crossbite in the opposite anterior teeth was also observed. Windowing and removal of odontoma-like hard tissue was performed under general anesthesia. Subsequently, eruption of deciduous anterior teeth as well as improvement of the crossbite were seen at follow-up examinations. On the other hand, odontoma-like hard tissue was found to be associated with severe enamel hypoplasia of the deciduous lateral incisor, which was also observed in the erupted deciduous central incisor and deciduous canine crown. This case had localized abnormalities and the affected location was under pressure during the intubation, thus we considered that the abnormalities were influenced by tracheal intubation performed during the neonatal period. Based on our findings, it is possible that enamel hypoplasia, crossbite, morphological abnormalities of the palate, and other abnormal conditions can be found in very low and extremely low birth weight children who receive tracheal intubation as neonates. Thus, appropriate examinations and treatment for such cases are essential.

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Trisomy 13 syndrome is an autosomal genetic disease caused by an extra chromosome 13 and 95% of affected individuals die within 1 year after birth. Due to the low survival rate, reports of oral findings in such patients are rare. Here, we present oral findings of a 14-year-old female who was diagnosed with partial trisomy 13 at a heredity clinic in a prefectural children's hospital at the age of 10 years. Her initial visit to our hospital was for displacement of the left upper canine. An oral examination revealed that the third molars were missing, the upper canines were displaced, and the tooth crowns had a large mesiodistal width, while a bilateral crossbite in the molar region was noted. Large amounts of dental calculus and severe gingivitis were also observed. We corrected malalignment and treated the dental caries, after which the patient entered a preventive program and for follow-up examinations every 2-5 months after treatment.

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