Katsura Saeki

Al and Fe levels in mixed saliva of children related to elution behavior from teeth and restorations

OBJECTIVES The levels of trace elements in mixed saliva were not well-defined. This study was performed to determine Al and Fe concentrations in mixed saliva of children and to investigate the relationship between these levels and dental caries. METHODS Among 562 collected mixed saliva specimens, 514 and 548 samples for analyses of Al and Fe levels were obtained, respectively. The Al and Fe concentrations were determined using flameless atomic absorption spectrometry. RESULTS The Al and Fe concentrations in children without a history of caries were 0.093±0.136 and 0.121±0.128 μg/mL, respectively. The Fe level depended on sex. The Fe level in girls who experienced caries was significantly higher than that without caries history. The Al and Fe levels were significantly higher in children with treated caries than children without caries history. The Fe concentrations were affected by restoration type. Composite resin increased the Fe level significantly especially in girls, and the Fe level was also higher in boys treated with both composite resin and metal restorations. In children without caries history, the Al level was inversely proportional to the number of deciduous teeth and increased with the number of permanent teeth. In contrast, the Fe level showed the reverse tendency. CONCLUSIONS The Fe level in mixed saliva of children was influenced by the restoration type. It was suggested that Al was eluted more from sound permanent teeth than sound deciduous teeth, while Fe was eluted in the opposite manner.

Pulp Revascularization in Immature Permanent Tooth with Apical Periodontitis Using Mineral Trioxide Aggregate

Mineral trioxide aggregate (MTA) is a material that has been used worldwide in several clinical applications, such as apical barriers in teeth with immature apices, repair of root perforations, root-end filling, pulp capping, and pulpotomy. The purpose of this case report was to describe successful revascularization treatment of an immature mandibular right second premolar with apical periodontitis in a 9-year-old female patient. After preparing an access cavity without anesthesia, the tooth was isolated using a rubber dam and accessed. The canal was gently debrided using 5% sodium hypochlorite (NaOCl) and 3% hydrogen peroxide irrigant. And then MTA was packed into the canal. X-ray photographic examination showed the dentin bridge 5 months after the revascularization procedure. Thickening of the canal wall and complete apical closure were confirmed 10 months after the treatment. In this case, MTA showed clinical and radiographic success at revascularization treatment in immature permanent tooth. The successful outcome of this case suggests that MTA is reliable and effective for endodontic treatment in the pediatric dentistry.

A spatial association between odontomas and the gubernaculum tracts

OBJECTIVES The purpose of this study was to identify the spatial relationship and/or association between odontomas and the gubernaculum tract or the dental sac and the characteristic findings for radiographic diagnosis of odontomas. STUDY DESIGN The visualizations of the odontomas and the gubernaculum tract were retrospectively analyzed using cone beam computed tomography or multidetector computed tomography. RESULTS Most of odontomas were within the gubernaculum tract or dental sac of unerupted permanent teeth on computed tomography. In some odontomas, the gubernaculum tract existed as a well-defined low density tract extending from the top of odontomas on computed tomography. CONCLUSIONS A close spatial relationship and/or association between odontomas and the gubernaculum tract or dental sac on computed tomography may be used as one of the criteria for radiographic diagnosis of odontomas. Development of odontomas may be associated with the gubernaculum tract or dental sac of unerupted permanent teeth.

Detection and imaging characteristics of the gubernacular tract in children on cone beam and multidetector computed tomography

PURPOSE To elucidate the appearance and imaging characteristics of the gubernacular tract (GT) during the growth stage of children. Furthermore, this study evaluated the significance of the appearance of the GT. STUDY DESIGN The visualizations of the GT were retrospectively analyzed by using panoramic radiographs and computed tomography (CT) in children. RESULTS In patients with normal eruption who had unerupted permanent teeth, except maxillary central supernumerary teeth, the GT was clearly visualized as a well-defined low-density tract on CT but not on panoramic radiographs. In patients with obstructive eruption, including impaction, the GT was deformed and not visible on CT. CONCLUSIONS This paper describes the frequency of detection and appearance of the GT in unerupted teeth. Preliminary data suggest that any alteration to the GT may be used to predict abnormal eruption of permanent teeth.

Supernumerary deciduous teeth with multiple maxillary impacted mesiodens: A case report

Maxillary impacted mesiodens are frequently encountered in pediatric dentistry. Much research has been conducted concerning their incidence, position, and form. Supernumerary teeth erupting in the primary dentition with maxillary impacted mesiodens are very rare. In January 2011, a nine-year-old boy presented for dental treatment and was found to have supernumerary deciduous teeth. Upon panoramic radiography, multiple impacted mesiodens were found; therefore, computed tomography (CT) was performed for further examination. One month later, the boy was referred to our department for extraction of the deciduous supernumeraries and impacted mesiodens. We suspected that these supernumeraries, mesiodens, and remaining primary teeth would lead to problems with the eruption of the permanent teeth. Therefore, by ascertaining the exact position of the mesiodens and the successional permanent teeth using CT, extraction was performed under general anesthesia in March 2011 without any error. Six months postoperatively, panoramic radiographs showed no superfluous structure that appeared to be a tooth. We suggest that when multiple maxillary impacted mesiodens are found, their exact positions can be located using CT before extraction.

Ameloblastin and enamelin prevent osteoclast formation by suppressing RANKL expression via MAPK signaling pathway

Ameloblastin (Ambn) and enamelin (Enam) play a pivotal role in enamel mineralization. Previous studies have demonstrated that these enamel-related gene products also affect bone growth and remodeling; however, the underlying mechanisms have not been elucidated. In the present study, we examined the effects of Ambn and Enam on the receptor activator of nuclear factor kappa-B ligand (RANKL) expression induced with 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and dexamethasone (DEX) on mouse bone marrow stromal cell line ST2 cells. We then verified the effect of Ambn and Enam on osteoclastogenesis. We found that pretreatment with recombinant human Ambn (rhAmbn) and recombinant human Enam (rhEnam) remarkably suppressed RANKL mRNA and protein expression induced with 1,25(OH)2D3 and DEX. Interestingly, rhAmbn and rhEnam attenuated the phosphorylation of mitogen-activated protein kinases (MAPK), including ERK1/2, JNK, and p38 in ST2 cells stimulated with 1,25(OH)2D3 and DEX. Moreover, pretreatment with specific inhibitors of ERK1/2 and p38, but not JNK, blocked RANKL mRNA and protein expression. Cell co-culture results showed that rhAmbn and rhEnam downregulated mouse bone marrow cell differentiation into osteoclasts induced with 1,25(OH)2D3 and DEX-stimulated ST2 cells. These results suggest that Ambn and Enam may indirectly suppress RANKL-induced osteoclastogenesis via downregulation of p38 and ERK1/2 MAPK signaling pathways in bone marrow stromal cells.

Significance and usefulness of imaging characteristics of gubernaculum tracts for the diagnosis of odontogenic tumors or cysts

We aimed to determine the significance and usefulness of imaging characteristics of gubernaculum tracts (GT) for the diagnosis of odontogenic tumors or cysts. This was a retrospective analysis of relationships between odontogenic or non-odontogenic tumors or cysts and the GT that were visualized using multi-detector computed tomography (MDCT). The relationship between the size of a mass and expansion of the GT in all odontogenic tumors or cysts to which GTs were contiguous on MDCT, was statistically analyzed. Intact or expanded GTs were detected in MDCT images on the top of almost all odontogenic tumors or cysts, but not on non-odontogenic tumors or cysts. Characteristic image findings regarding the relationship between the GT and the odontogenic mass were detected for the respective odontogenic tumors or cysts in which the GTs were contiguous to the mass on MDCT. In ameloblastomas, expansion of the GTs significantly and very strongly correlated with tumor size (r = 0.741, p = 0.0001), but this correlation was very weak in dentigerous cysts (r = 0.167, p = 0.028) and there was no correlation between these parameters in odontogenic keratocysts (r = -0.089, p = 0.557). The imaging characteristics of GTs at the top of masses should be very useful for both the differential diagnosis of the pathological diagnosis of odontogenic masses and for differentiation between odontogenic and non-odontogenic masses.

Influence of childhood type II diabetes on bone formation in the growth period

Abstract The influence of childhood type II diabetes on bone formation in the growth period was investigated using the mouse mandible, femur, and tibia. Five-week-old mice with spontaneous type II diabetes (KK-A Y ) and C57BL/6J mice as a control group were used. Animals were randomly divided into 3 groups, and the regions were excised after 1, 5, and 13 weeks. Regarding the bone length, growth of the femur and tibia was greater in the KK-A Y than in the control group, and that of the mandible varied depending on the measurement site. On P-QCT, the trabecular and cortical bone mineral densities of the femur were higher in the KK-A Y than in the control group, whereas those of the head of the mandible were higher in the control. The thickness and circumferences around the exosteum and endosteum of the cortical bone were significantly different between the KK-A Y and control groups, and X-SSI, Y-SSI, and Polar-SSI of the femur and head of the mandible, were significantly different. The μCT findings were correlated with the p-QCT findings. Bone morphometry clarified that bone formation of long bone at the early age was more active in the KK-A Y than in the C57BL/6J group, and bone resorption was promoted with aging in the head of the mandible. These findings suggested that not only the bone length but also bone quality tend to increase in the growth period in childhood type II diabetes.

Magnetic Resonance Angiography Using Fresh Blood Imaging in Oral and Maxillofacial Regions

The present paper provides general dentists with an introduction to the clinical applications and significance of magnetic resonance angiography (MRA) in the oral and maxillofacial regions. Specifically, the method and characteristics of MRA are first explained using the relevant MR sequences. Next, clinical applications to the oral and maxillofacial regions, such as identification of hemangiomas and surrounding vessels by MRA, are discussed. Moreover, the clinical significance of MRA for other regions is presented to elucidate future clinical applications of MRA in the oral and maxillofacial regions.

Alterations of the Temporomandibular Joint on Magnetic Resonance Imaging according to Growth and Development in Schoolchildren

The paper explains the alterations of the temporomandibular joint (TMJ) visualized by magnetic resonance imaging (MRI) according to the growth and development of schoolchildren. Appearance and disappearance of a “double contour-like structure” (DCLS) of the mandibular condyle on MRI according to the growth and development of schoolchildren were demonstrated. In addition, possible constituents of DCLS and the significance of detection of DCLS on MRI were also speculated. The relationship between red marrow and yellow marrow in the articular eminence of temporal bone, the disappearance of DCLS, and alterations of the mandibular condyle have been elucidated.