Temporal and dynamic changes in gingival blood flow during progression of ligature-induced periodontitis.

OBJECTIVES: To evaluate temporal changes in gingival blood flow (GBF) during progression of periodontitis in rats using a laser Doppler flowmeter (LDF) approach and to characterize morphological and biochemical features in the periodontium associated with GBF. MATERIALS AND METHODS: Forty-two Wistar rats were divided into a ligature-induced periodontitis group and a control group. To induce periodontitis, ligatures were tied around maxillary first molars bilaterally. GBF was measured in palatal gingiva at pretreatment and following ligature placement after 30 min, 1, 3, 7, 14, 21, and 28 days using LDF with a non-contact probe. Bone loss and gene expression in gingival tissues were assessed using micro-computed tomography (µCT) and quantitative polymerase chain reaction (PCR), respectively. Immunostaining for vascular endothelial growth factor (VEGF) in the maxilla was also histologically evaluated. RESULTS: GBF in the ligature group increased significantly compared with the control group 30 min after ligation. However, on days 3 and 7, GBF decreased in the ligature group. Also, after day 10, there was no difference in GBF between groups. The levels of alveolar bone loss, gene expression (interleukin-6, cluster of differentiation-31, VEGF-A, and lymphatic vessel endothelial hyaluronan receptor-1), and immunostained VEGF-positive vessels correlated well with changes in GBF. CONCLUSION PROGRESSION OF PERIODONTITIS: In rats was associated with a triphasic pattern of GBF, consisting of a short initial increase, followed by a rapid decrease, and then a gradual plateau phase.

Spatiotemporal expression profiles of c-Mpl mRNA in the tooth germ: Comparative expression dynamics of vascularization-related genes.

BACKGROUND: Vascularization is an essential event for both embryonic organ development and tissue repair in adults. During mouse tooth development, endothelial cells migrate into dental papilla during the cap stage, and form blood vessels through angiogenesis. Megakaryocytes and/or platelets, as other hematopoietic cells, express angiogenic molecules and can promote angiogenesis in adult tissues. However, it remains unknown which cells are responsible for attracting and leading blood vessels through the dental papilla during tooth development. METHODS: Here we analyzed the spatiotemporal expression of c-Mpl mRNA in developing molar teeth of fetal mice. Expression patterns were then compared with those of several markers of hematopoietic cells as well as of angiogenic elements including CD41, erythropoietin receptor, CD34, angiopoietin-1 (Ang-1), Tie-2, and vascular endothelial growth factor receptor2 (VEGFR2) through in situ hybridization or immunohistochemistry. RESULTS: Cells expressing c-Mpl mRNA was found in several parts of the developing tooth germ, including the peridental mesenchyme, dental papilla, enamel organ, and dental lamina. This expression occurred in a spatiotemporally controlled fashion. CD41-expressing cells were not detected during tooth development. The spatiotemporal expression pattern of c-Mpl mRNA in the dental papilla was similar to that of Ang-1, which preceded invasion of endothelial cells. Eventually, at the early bell stage, the c-Mpl mRNA signal was detected in morphologically differentiating odontoblasts that accumulated in the periphery of the dental papilla along the inner enamel epithelium layer of the future cusp region. CONCLUSION: During tooth development, several kinds of cells express c-Mpl mRNA in a spatiotemporally controlled fashion, including differentiating odontoblasts. We hypothesize that c-Mpl-expressing cells appearing in the forming dental papilla at the cap stage are odontoblast progenitor cells that migrate to the site of odontoblast differentiation. There they attract vascular endothelial cells into the forming dental papilla and lead cells toward the inner enamel epithelium layer through production of angiogenic molecules (e.g., Ang-1) during migration to the site of differentiation. C-Mpl may regulate apoptosis and/or proliferation of expressing cells in order to execute normal development of the tooth.

Nisin lantibiotic prevents NAFLD liver steatosis and mitochondrial oxidative stress following periodontal disease by abrogating oral, gut and liver dysbiosis.

Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum, were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin's ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

Bimodal expression of Wnt5a in the tooth germ: A comparative study using in situ hybridization and immunohistochemistry.

BACKGROUND: During tooth development, Wnt5a, a member of the noncanonical Wnt ligand, is expressed prominently in the dental mesenchyme. However, the spatiotemporal profiles of Wnt5a protein production and distribution in tooth germs are largely unknown, which impairs elucidation of the Wnt5a-mediated regulatory mechanism of tooth development. METHODS: We performed analyzes of the spatiotemporal expression of Wnt5a in embryonic tooth germs (E11.5-E18.5) by using in situ hybridization and immunohistochemistry in parallel. The developmental stages of the embryonic tooth germs were determined by HE staining. In order to compare the spatiotemporal distribution patterns of Wnt5a mRNA-expressing cells and those of Wnt5a protein-expressing cells, serial frontal sections of paraffinized mouse embryo heads were used for the analyzes. When needed, the immunohistochemistry images were subjected to digital detection analysis of Wnt5a immunostaining signal using the WinROOF 2018 Ver. 4.19.0 image processing software program. RESULTS: Throughout the developmental process, cells expressing Wnt5a mRNA were found in various tissues including the dental follicle, dental papilla, inner and outer enamel epithelium, stratum intermediate, and stellate reticulum. However, odontoblasts differentiating and polarizing at E18.5 were the only cells representing an accumulation of Wnt5a protein in the apical region of the odontoblast process. The Wnt5a protein was undetectable in undifferentiated mesenchymal cells as well as any other cells positive for Wnt5a mRNA. CONCLUSION: Differentiating odontoblasts execute Wnt5a expression, the mode of which is distinct from that executed by the other cells constituting tooth germ. Change of the mode of Wnt5a expression begins to take place in the mesenchymal cells by E18.5, starting the elongation of the cytoplasmic process.

Analysis of vascular distribution and growth factors in human gingival tissue associated with periodontal probing depth.

SUMMARY: Vascular endothelial growth factor (VEGF) is a key regulator of blood vessel endothelium. Tissue levels of this angiogenesis marker are unknown in human gingival tissue, as is the correlation between vascular growth factors and hypoxia-inducible factor. We examined the expression of VEGF, type III tyrosine kinase receptors (VEGF-R2), platelet-endothelial cell adhesion molecule (CD31) and hypoxia-inducible factor (HIF) mRNA from human gingival tissue of the oral cavity. Tissue samples were from a small quantity of gingival sample biopsy with gingival sulcular depth (GSD) < 2 mm (Group 1), 2 to 4 mm (Group 2), and > 4 mm (Group 3). We found that the levels of VEGF-R2, CD31 and HIF mRNA were higher in the gingival tissue of Group 2 than that of Group 1, and VEGF in the Group 3 was also higher than that of Group 1. The different mRNA levels of these markers may reflect the mRNA levels reflect the vasculature state of gingival tissue based on GSD. VEGF-R2 and HIF also indicate the presence of an elongated blood vessel in the gingival tissue. In the early stage of angiogenesis, VEGF-R2 leads to expression of VEGF, and HIF-1 mediates increased VEGF expression in response to hypoxia in swollen tissues or during the expansion of periodontal tissues, which is useful in the early diagnosis of periodontal diseases.

A morphological study of the blood vessels associated with periodontal probing depth in human gingival tissue.

Gingival tissues in human cadavers were examined the blood vessel diameter in the depths of the gingival pockets such as three groups: gingiva adjacent to a sulcus of 2 mm (Group 1); gingiva adjacent to a 2-4-mm sulcus (Group 2); and gingiva adjacent to a sulcus of > 4 mm (Group 3). A meaningful significant difference was seen observed in gingival pocket side, intermediate and outer layer side regions of the gingiva. A meaningful significant difference was seen found in intermediate part and the outer layer of the gingiva in Group 3. Other gingival biopsies were performed on a human body donation specimen to examine CD-31 positive endothelial cells of blood vessels by an immnohistochemical method. Our results suggest that the periodontal probing depth reflect the blood vessel organization of human gingival tissue.

Understanding the formation of maxillary sinus in Japanese human foetuses using cone beam CT.

The formation of the maxillary sinus (MS) is tied to the maturation of the craniofacial bones during development. The MS and surrounding bone matrices in Japanese foetal specimens were inspected using cone beam computed tomography relative to the nasal cavity (NC) and the surrounding bones, including the palatine bone, maxillary process, inferior nasal concha and lacrimal bone. The human foetuses analysed were 223.2 ± 25.9 mm in crown-rump length (CRL) and ranged in estimated age from 20 to 30 weeks of gestation. The amount of bone in the maxilla surrounding the MS increased gradually between 20 and 30 weeks of gestation. Various calcified structures that formed the bone matrix were found in the cortical bone of the maxilla, and these calcified structures specifically surrounded the deciduous tooth germs. By 30 weeks of gestation, the uncinate process of the ethmoid bone formed a border with the maxilla. The distance from the midline to the maximum lateral surface border of the MS combined with the width from the midline to the maximum lateral surface border of the inferior nasal concha showed a high positive correlation with CRL in Japanese foetuses. There appears to be a complex correlation between the MS and NC formation during development in the Japanese foetus. Examination of the surrounding bone indicated that MS formation influences maturation of the maxilla and the uncinate process of the ethmoid bone during craniofacial bone development.

Evaluation of the blood and nerve supply patterns in the molar region of the maxillary sinus in Japanese cadavers.

The maxillary sinus (MS) in the maxilla bone is located near the orbit, the nasal cavity and the oral cavity; however, the positioning of the constituent bones is complex. The posterior superior alveolar branches of the maxillary artery and nerve are distributed in the lateral wall of the MS. The courses of these blood vessels and nerves are restricted by the morphology of the craniofacial bones, and the landmarks used in dental implant treatment of these courses mainly run along the lateral wall of the MS. In this study, 19 human cadavers with 34 sides of Japanese origin (ranging in age from 59-94 years, mean 77.7 +/- 9.8 years) were prepared for measurement of the MS, the superior alveolar artery and the infraorbital artery using cone beam computed tomography (CBCT). The posterior superior alveolar artery (PSAA) of the lateral wall of the MS can be classified into one of three groups based on the supply pattern. In the greatest number of cadavers, the PSAA ran mainly to the lateral surface of the zone between the superior border of the alveolar foramen and the inferior border of the MS (53.0%, 18/34). In others, the PSAA ran to the zone between the infraorbital foramen and the superior border of the alveolar foramen (17.6%, 6/34); in a third group, the PSAA ran to the zone between the inferior border of the MS and the greater palatine foramen (23.5%, 8/34). The lest of two sides are spread out in this area (5.9%, 2/34). CBCT is the most accurate tool to evaluate important anatomical parameters, such as the distance of the blood supply, for the implant of grafts in the floor of the MS during surgical procedures.

Distribution of glutamate receptor, ionotropic, kainate 1 and neuropeptide calcitonin gene-related peptide mRNAs during formation of the embryonic and postnatal mouse molar in the maxilla.

The neuropeptide calcitonin gene-related peptide (CGRP) is a well-characterized neurotransmitter. Glutamate receptor, ionotropic, kainate 1 (Grik1) has also been demonstrated to generate high-affinity kainate receptors. However, little is known about the roles of CGRP and Grik1 during the developmental formation of teeth. In this study, we endeavoured to analyse the expression and localization of CGRP and Grik1 mRNAs using in situ hybridization on the mouse maxilla during development from the embryonic stage (E18.5) to after birth (P10, P15 and P20). We found that hybridization with an anti-sense probe for CGRP clearly localized in the maxilla at E18.5 in contrast to that of P15 and P20. Hybridization with an anti-sense probe for CGRP was not detected in the dental pulp of molars in the maxilla at P10, which is in contrast to Grik1 mRNA at the same developmental stage. Hybridization with an anti-sense probe for Grik1 mRNA was detected in the basal region of the dental pulp of molars at P10 and P15. Finally, these markers were not detected in molars in the mouse maxilla at P20. The ratio of positive cells for the hybridization signals of Grik1and CGRP in the dental pulp decreased from E18.5 (p<0.001). These features in CGRP and Grik1r mRNAs may indicate roles of function during tooth development between embryonic and postnatal stages with root formation and erupted movements.

Immunocytochemical localization of vascular endothelial growth factor and vascular endothelial growth factor receptor-2 of the human deciduous molar tooth germ development in the human fetus.

Vascular endothelial growth factor (VEGF) is a key regulator of blood vessel endothelial development. We used immunohistochemical methods to demonstrate the localization of VEGF and its receptors, showing the specific expression pattern of VEGF and VEGF receptor in the human deciduous tooth from the cap to late bell stages in the human fetus. Immunoreactivity to VEGF and its receptor VEGF receptor-2 (VEGFR-2) was intensely positive in the inner enamel epithelium at the cap stage and ranged from negative to moderately positive in the bell stage. At the late bell stage, VEGF immunoreactivity was mainly positive but weak for VEGFR-2. The intensity of VEGF and VEGFR-2 in odontoblasts increases from cap stage to late bell stage. We postulate that the dissimilar expression of VEGF in inner enamel epithelium, ameloblast and odontoblast during each stage of human tooth development may affect tooth germ formation.

Distribution of LYVE-1 and CD31 in postnatal rat masseter muscle.

During the development of blood vascular systems in the masseter muscle, one functional property of the blood supply via capillaries is altered by the change in feeding pattern from suckling to mastication. The lymphatic vessel hyaluronan receptor-1 (LYVE-1) is a marker of lymphatic endothelial cells. The PECAM (CD31) is also an important marker of vascular endothelial cells and lymphatic cells. The mechanisms by which circulating lymphatic endothelial cells from blood vessels in masseter muscle form a network of lymphatic capillaries and vessels functioning in jaw muscle movement remain unknown. In our results, LYVE-1- and CD31- positive reactions were located in almost identical regions at the stages examined using double immunofluorescence staining. However, the level of protein for LYVE-1 and CD31 differed between superficial and deep regions in postnatal rat masseter muscle using Western blotting analysis. The different distribution of LYVE-1 and CD31 antibody reactions was found in the deep region in contrast to that of the superficial area in 3-7-week-old rat masseter muscles. Concomitant with the increased level of protein for CD31 in the deep region, many small vessels branch in this region during development in rat masseter muscle. Therefore, different levels of protein and immunohistochemical reactions for CD31- and LYVE-1-positive cells may reflect alterations in the functional properties of the blood supply and collection via capillaries due to the changes in feeding pattern.

CBCT imaging of the alveolar bone structure in maxilla of elderly donor cadavers and PCA analysis.

There is an important bone matrix with remodelling between dentate and edentulous samples of the human maxilla for bone metabolism. Cone beam computed tomography (CBCT) is useful for structural analysis of bone. The objective of this study was to investigate morphological data of donor cadavers in detail using CBCT imaging and principal component analysis (PCA). We analysed 38 donor cadavers using a CBCT apparatus. The analytical results defined differences in skull measurement parameters and dentate and edentulous levels using PCA. We observed cortical bone, trabecular bone, and the distance from the bottom of the maxillary sinus to the oral mucosa at a right angle to the palatal plane of the first molar region between dentate and edentulous samples of the human maxilla using CBCT imaging. In the dentate sample of the maxilla, component 1 was defined by negative contributions from gender (-0.84) and age (-0.54) to positive contributions such as cortical bone structure (CBS, 0.68) and trabecular bone structure (TBS, 0.50). There was a difference in CBS between dentate and edentulous human maxilla samples. This study of CBCT data provides useful basal information for planning dental implant surgery using PCA.

Immunohistochemically localization of vascular endothelial growth factor, vascular endothelial growth factor receptor-2, collagen I and fibronectin in the epithelia-mesenchymal junction of the human tooth germ.

During tooth development, tooth shape is mediated by the ECM through epithelial-mesenchymal interactions mediated by the ECM at the epithelia-mesenchymal junction. Blood vessel endothelium growth is mainly regulated by vascular endothelial growth factor (VEGF) and the relationship between tooth shape formation and VEGF are unknown. We examined immunohistochemical localization of VEGF and its receptor VEGF receptor-2 (VEGFR-2), collagen I and fibronectin, (both representative protein of ECM) at the epithelia-mesenchymal junction of human deciduous teeth from the cap stage to late bell stages in a human fetus at 16, 20, 24, 28 and 32 weeks of gestation. Immunoreactivity at the basement membrane for VEGF was detected from the cap stage to the bell stage. Immunoreactivity to fibronectin was weak in the cap stage and increased in the bell stage; collagen I was negative in the cap stage and slightly expressed in the bell stage in the basement membrane. We suggest that VEGF and ECM affect cooperatively in tooth shape formation at the basement membrane.

A morphological study of the foramina of the mandible in the Japanese macaque by cone-beam computed tomography.

The mandibular canal (MC) contains vessels and nerves in the mandible of the Japanese macaque (JM). The inferior alveolar nerves and vessels of the mandible insert from the mandibular foramen and then run through the MC, the mental foramen and spinal foramen to the outside of the mandible. However, the detailed morphological properties of multiple canals, such as the accessory canal (AC) of the mandible, are unknown in JMs. The purpose of this study was to describe the multiple canals of JMs and to determine the location and analyse the measurements of the JM mandible. In this study, we also showed the course of the lingual foramen in 17 JMs (male: n = 8; female: n = 9) using cone-beam computed tomography (CBCT). In our results, we classified multiple mental foramina and multiple lingual foramina found on the mandibular body at the premolar or molar region. However, there was no significance between the formation of mandibular properties and the lingual foramen. These multiple foramina contain nerves and blood vessels have a few branched canals; these branches run downward and connect with the inferior mandibular nerve and artery. These morphological features may provide useful information about surgical treatment of the alveolus in a human model.

Immunohistochemical localization of vascular factors in tooth germ of amphibian (Cynops pyrrhogaster) / Localización inmunohistoquímica de factores vasculares en germen dentario de anfibios (Cynops pyrrhogaster)

SUMMARY: Vascular endothelial growth factor (VEGF) and its receptor, VEGFR-2, are known to regulate blood vessel endothelium growth. They play important role in human and rodents teeth development. In newt jaws, there are sequential developmental teeth germs following behind the mature teeth. We examined the immunohistochemical localization of VEGF and its receptor and showed the specific expression pattern of VEGF and VEGF receptor in Cynops pyrrhogaster sequential tooth development. The intensity of immunoreactivity for VEGF in the inner enamel epithelium was weaker than that in the outer enamel epithelium in the dentine matrix formation and mineralization stages. Finally, at the enameloid maturation and enamel-like matrix formation stage, immunoreactivity for VEGF in inner enamel epithelium was stronger than in the outer enamel epithelium. The intensity of immunoreactivity for VEGFR-2 was positive for the outer enamel epithelium throughout tooth development. The crown sides of the odontoblasts were stained especially strongly for VEGF and VEGFR-2 during the dentine matrix formation and mineralization stage of the enameloid maturation and enamel- like matrix formation stage. We postulate that the expression of VEGF in the inner enamel epithelium and odontoblast widely effects tooth development in newts, as well as in human and rodents.

RESUMEN: Se sabe que el factor de crecimiento endotelial vascular (VEGF) y su receptor, VEGFR-2, regulan el crecimiento del endotelio de los vasos sanguíneos. Desempeñan un papel importante en el desarrollo de los dientes humanos y de los roedores. En las mandíbulas de tritón, hay gérmenes dentales de desarrollo secuenciales que siguen a los dientes maduros. Examinamos la localización inmunohistoquímica de VEGF y su receptor y mostramos el patrón de expresión específico de VEGF y receptor de VEGF en el desarrollo secuencial de dientes de Cynops pyrrhogaster. La intensidad de la inmunorreactividad para VEGF en el epitelio interno del esmalte era más débil que en el epitelio externo del esmalte en las etapas de formación y mineralización de la matriz de dentina. Finalmente, en la etapa de maduración del esmalte y de formación de la matriz similar al esmalte, la inmunorreactividad para VEGF en el epitelio interno del esmalte fue más fuerte que en el epitelio externo del esmalte. La intensidad de la inmunorreactividad para VEGFR- 2 fue positiva para el epitelio externo del esmalte durante el desarrollo del diente. Los márgenes de la corona de los odontoblastos se tiñeron especialmente para VEGF y VEGFR-2 durante la etapa de formación de la matriz de dentina y mineralización de la etapa de maduración del esmalte y la etapa de formación de la matriz similar al esmalte. Postulamos que la expresión de VEGF en el epitelio interno del esmalte y odontoblastos afecta ampliamente el desarrollo de los dientes en tritones, así como en humanos y roedores.

A morphological study of the multi-posterior superior alveolar canals of maxilla in the Japanese macaque by cone-beam computed tomography.

The posterior superior alveolar canal (PSAC) composed of several canals which contains vessels and nerve in molar region of the maxilla of Japanese macaque. The PSAC of maxilla run to the maxillary sinus. However, the PSAC and accessory canal (AC) of the maxilla in the Japanese macaque (JM) is unknown in morphological features in the maxilla. The purpose of this study was to describe the PSAC of the primates and to determine whether this structure could be used as a model for the human clinical condition. In this study, we showed the course of PSAC structure of the 23 JMs (male: n = 15; female: n = 8) using a cone-beam computed tomography apparatus. In the results, we classified a type to have one AC toward, a type to have two ACs toward, and three ACs in a type to have in PSAC. The main canal have some bony branch canals (BBCs) composed of 3 types (no BBC, one BBC, two BBCs). These canals and they run downward and supply to MS, these roots of maxillary molar region of the craniofacial skeleton in contrast to numerous small accessory canals with no nerve and vessels observed in the posterior regions in maxilla. These morphology features may give useful information about MS in dental treatment human model.

The appearance of foramen in the internal aspect of the mental region of mandible from Japanese cadavers and dry skulls under macroscopic observation and three-dimensional CT images.

The lingual canal with foramen displays different appearances on the internal surfaces of mandible as confirmed by macroscopic observation and computerized tomography (CT). The lingual canal was observed in the inside of mental region run to the outside of lingual foramen, which is extend internally from mandibular canal in right and left sides of the mandible in cadavers (13 sides out of 88 sides) and in dry skulls (43 out of 94 sides) examined. The spinal foramen connected with mental canal occurred at the midline of mandible in 6 cases (6 out of 47 cases) in dry skulls. In this small foramen, the inferior alveolar artery give some branches to the inside of mental region at the anterior mandible and which may be run pass through the lingual canal to the lingual foramen, where they emerge to enter the mylohyoid or anterior belly of digastric muscles. The observations of these are important considerations for surgical placement of dental implants in the region in the mandible.

Branch of mylohyoid and lingual nerves on submandibular and submental triangles.

The mylohyoid nerve (MN) displays several branches in the posterior, intermediate, and anterior region of the mylohyoid muscle (MM) as it courses on the internal surface of the mandibular body. Branches in the intermediate region were found in 66% of the cases (272 out of 413 sides). In the submandibular triangle, one or two large branches of the MN communicated with the lingual nerve at submandibular triangle and submental triangle in 1.45% of the cases (6 out of 413 sides). These distributions of nerve supply are an important in the operations of radical neck dissection on the submandibular triangle.

Distribution of tenascin-c and -X in rat TMJ development.

In the neonatal and postnatal development of rat TMJ, tenascin-C and -X were detected in the muscle, bone matrix, connective tissue around the bone, and blood vessel of rats at E18 (18-days old embryo), 0-, and 5-days postnatal. The reaction of tenascin-X was also found in the connective tissue around the mandibular condyle. The mRNA of tenascin-C (600 bp) and -X (588 bp) was also detected in the developmental muscle with the level of tenascin-C mRNA moderately decreased during development. Therefore, tenascin-C and -X may have different effects on the connective tissue during development of TMJ.

Differences in the morphology of the maxillary sinus and roots of teeth between Macaca fuscata and Macaca fuscata yakui determined using cone beam computed tomography.

The Japanese macaque is an endemic species consisting of two subspecies: Macaca fuscata fuscata (MFF) and Macaca fuscata yakui (MFY). The MFY is indigenous to Yakushima Island and represents a subspecies of MFF that lives from Honshu to Shikoku and Kyushu, Japan. However, the differences in the skulls of the MFY and MFF are unknown, despite these subspecies having different skull sizes. The maxillary sinus (MS) indicates that the features of the frontal view reflect the transversal growth of the maxilla of the skull. In this study, we show the MS structures of the MFF (n = 9, 18 sides) and MFY (n = 10, 20 sides) using a cone-beam computed tomography instrument. Base on three-dimensional (3D) reconstructed images the MS and nasal cavity were found to present almost to no significant differences between MFF and MFY. However, we designated three classifications of the sinus floor based on the 3D MS images of these Japanese macaques: a round-like shape (type a, MFF = 66.7% (12/18), MFY = 45% (9/20)), a flat-like shape (type b, MFF = 22.2% (4/18), MFY = 35% (7/20)), and an irregular shape (type c, MFF = 11.1% (2/18), MFY = 20.0% (4/20)). The sinus floor shapes of the MFF were mostly type a, while those of the MFY were mostly type b. The prevalence of a root contacting the cortical bone is higher in the canine (26.7%, (8/30)) and second premolar (20%, (6/30) of the MFY at the nasal cavity, moreover, this value is higher in the third molar (42.9%, (9/21)) of the MS in the MFY. These results suggest that the features of the floor of the MS are related to the differences in maxillary root apices teeth between MMF and MMF.