In the present study, tissue responses of two types of three-dimensional titanium fiber structure, namely, titanium web (TWe) and titanium wire (TWi), were evaluated for external and internal bone augmentation, respectively. TWe was produced by sintering intertwined thin titanium fibers. TWi was produced by interweaving thin titanium fibers without a sintering process. The mechanical strength was superior in TWe and the formability was superior in TWi. As surface modifications of TWe and TWi, both CA coating using a molecular precursor method and immobilization of cell-adhesive protein, collagen and fibronectin, using the tresyl chloride-activated method were employed. TWe materials were implanted under the periosteum of rat calvaria to evaluate the external bone augmentation. TWi materials were implanted into the bone defect of rabbit femoral condyle to evaluate the internal bone augmentation. After 4 and 8 weeks for rat experiments with TWe materials and 12 weeks for rabbit experiments with TWi materials, new bone formation inside the porous area of the fiber structure was histologically evaluated. The bone formation rate (BFR) and the vertical bone augmentation rate (VBR) were also histomorphometrically analyzed. BFR and VBR of CA-coated TWe and TWi were significantly higher than those of non-coated TWe and TWi, respectively, for rat external and rabbit internal bone augmentation (p<0.05). BFR of collagen- or fibronectin-immobilized TWi was significantly higher than for non-coated TWi for rabbit internal bone augmentation (p<0.05), but not for rat external bone augmentation (p>0.05). In conclusion, it is suggested that surface-modified three-dimensional titanium fiber structure is a good candidate as a three-dimensional scaffold for regenerative medicine.

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To date, more than 120 total types of HPV have been identified, and in a recent meta-analysis, HPV was confirmed as an independent risk factor for oral carcinoma. Some investigators have reported that HPV infection is related to certain factors, including the gender, age, alcohol consumption, smoking habit, sexual behavior and denture wearing. Denture wearing can lead to denture epulis, which is a hyperplasia of fibrous connective tissue caused by denture irritation. Recently, HPV infection was detected in the hyperplastic epithelium of denture fibroma, but it still has received little study. The objective of the present investigation, therefore, was to clarify the relationship between the hyperplastic epithelium of the denture epulis and HPV infection. DNA of 118 formalin-fixed, paraffin-embedded hyperplastic epithelium biopsies of epulis specimens was extracted. Firstly, HPV infection was detected by PCR using consensus primers. Secondary, PCR using HPV type-specific primers (low risk types 6 and 11; high risk types 16, 18 and 33) was done in positive PCR samples. HPV infection was also detected by in situ hybridization and immunohistochemical techniques. Eighteen (23.1 %) of the 78 cases of denture epulis were positive, and 2 (5.0 %) of the 40 cases of non-denture epulis were positive. The difference was statistically significant (p<0.05, using Fisher’s exact test). The most frequent type of HPV found in the 14 positive samples was HPV 16. It seems that the hyperplastic epithelium of denture epulis is easily infected with viruses because the epithelium is exposed daily to traumatic irritation from dentures. These results suggest that the hyperplastic epithelium of denture epulis might be an important reservoir for HPV infection of the oral region where later HPV-associated diseases, such as oral cancer and other oral lesions, may develop.

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Orthodontically-induced inflammatory root resorption (OIIRR) is one of the procedure-related adverse effects that occur during orthodontic treatment, and the incidence is related to the proinflammatory cytokine produced in response to the mechanical stress caused by the procedure. It is known that tumor necrosis factor (TNF)-α is produced following environmental insults in vivo at an early stage, and that it deeply affects inflammatory bone resorption. However, the relationship between the TNF-α level and root resorption is unclear. In this study, the relationship between TNF-α and root resorption was evaluated using an experimental mouse tooth movement model and a pressure side model using human periodontal ligament (hPDL) cells, as well as an osteoclast culture system. Nine days after the tooth movement in the mouse model, an increase in TNF-α and receptor activator of nuclear factor-κB ligand (RANKL) positive cells was observed. In vitro, their levels increased in the cultures of hPDL cells exposed to the 4 g/cm² pressure. In addition, the differentiation of osteo/odontoclasts was promoted by TNF-α weakly, but the ability to resorb the dentin was unchanged. However, the activation of osteo/odontoclastogenesis is more potent in the presence of RANKL and TNF-α, which leads to synergistic activation. These results suggest that TNF-α may be an aggravating factor for root resorption during orthodontic treatment.

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This study focused on the abnormality of dentin matrix to clarify the pathogenesis of human dentinogenesis imperfecta (DI). Dentin matrix of mandibular molars from wild type (Zip13+/+) and Slc39a/Zip13 knockout (KO) mice were examined histologically. Hematoxylin and eosin, as well as silver staining, were used for light microscopy. Samples were also observed under backscattered and transmission electron microscopy. Immunohistochemistry using type I collagen was also carried out. Results showed that Zip13-KO mice exhibited 1) lamellated dentin matrix with accentuated incremental lines under the light microscope, 2) abnormal collagen fibers and round shape collagen molecules in transmission electron microscope, and 3) unusual immunoreaction to collagen type I. The similarity in the histological features of dentin in Zip13-KO mice to human DI indicates that Zip13-KO mice may be used as models for investigating the mechanism of human DI.

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We have developed a novel supplement diet for osteoporosis prevention that contains fructo-oligosaccharide, isoflavone, and calcium citrate, in addition to calcium phosphate (high mineral diet: HMD). The present study aimed to clarify whether rats with osteoporosis fed an HMD showed an improved structure model index (SMI) in the femoral epiphyseal region compared with rats fed a normal mineral diet (NMD). The experiment used 20-week-old ovariectomized rats divided into an NMD group (n=6) and an HMD group (n=6). After 24 weeks on the diet, this study examined the changes in SMI and the 3-dimensional pseudocolor map (3D-map) using micro-computed tomography. Compared to the NMD group, the HMD group had significantly greater Trabecular Thickness (Tb. Th) and Trabecular Number, and shorter Trabecular Separation and Trabecular Spacing, indicating highly dense trabeculae. The trabeculae of the NMD group had low Tb. Th and bone volume / tissue volume (BV/TV), indicating a thin, rod-like shape, but the trabeculae of the HMD group had significantly greater Tb. Th and BV/TV, demonstrating a thick, plate-like structure. In the sagittal section image of the 3D-map, the trabecular bone of the NMD group showed low bone mineral density (BMD), represented by light blue and purple colors, on the growth plate side of the inner portion of the cortical bone, indicating near complete resorption of the trabecular bone. The trabecular bone of the HMD group showed moderate to low BMD, represented by light blue and green colors, on the growth plate side, indicating a greater trabecular bone density compared to the NMD group.
The present results showed that the intake of HMD, compared to NMD, maintains the trabecular structure by preventing trabecular bone resorption, indicating the usefulness of HMD intake.

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The aim of this study was to evaluate the effects of alendronate immobilization on bone formation following the implantation of apatite-coated titanium implants in rats. Thin carbonate-containing apatite coatings were deposited onto titanium implants (Ti implants) using a molecular precursor method. Alendronate was then immobilized on apatite-coated titanium implants (HA implants) by immersing the HA implants in alendronate solution (Ald implants). The rat molars were extracted, and the implants were immediately placed in the tooth sockets. Bone labeling was performed 14 and 7 days before sacrifice. At 3 and 9 weeks after implantation, undecalcified sections were prepared and bone histomorphometry was performed. Greater bone mass was found around the Ald implants than around either the Ti or HA implants at both 3 weeks and 9 weeks. At 3 weeks, fluorochrome bone labeling was greater around the Ald implants than around the Ti implants, and the values of bone to implant contact (BIC) and bone mass (BM) were significantly greater around the Ald implants than around the HA and Ti implants. At 9 weeks, bone labeling decreased and the values of BIC and BM increased compared with those at 3 weeks for all types of implant. In conclusion, we found that immobilized alendronate triggered pronounced bone formation around the implants at an early stage of bone healing. These results suggest that alendronate immobilization accelerates implant fixation early in the healing phase.

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FThe purpose of this study is to clarify the destructive processes of periodontal tissue, especially of alveolar bone, induced by food impaction. Streptozotocin-induced diabetic rat was used, gutter percha point (GP) was inserted into interdental gingival col space between upper M1 and M2, and the change of body weight, histopathological findings and 3D SEM structure of alveolar bone were compared between diabetic (Group DM) and control (Group N) animals (Experiment 1). Large amounts of bacterial deposits and sequester were observed at the alveolar crest, and subsequently experiment 2 was carried out to explore the relationship between bacterial infection and sequester formation. The combination of mechanical compression and daily twice cleaning with 3% oxydol and Periocline were carried out. As a result of experiment 1, ulceration with partial exposure of alveolar crest, inflammatory infiltrates and hyaline degeneration occurred in the col, and bone resorption was scarcely observed at 1d in Group N. Bone resorption of alveolar bone progressed at 3d and 5d, decreasing the height of alveolar crest and the width of alveolar bone. Reepithelization of ulcer surface was observed at 7d and 14d, and concurrently bone resorption regressed and new bone formation suggested reparative changes. SEM observation confirmed these changes of alveolar bone. On the contrary, massive bacterial deposits were observed, and bone resorption was scanty in the upper region and slight in the middle to lower region of alveolar bone at 1 day of Group DM. Massive bacterial deposits with partial exposure of alveolar bone were observed at 3d and 5d, and sequester was isolated owing to intense undermining bone resorption. Regeneration of epithelium was seen beneath the sequester at 14d, showing the phenomenon of foreign body exclusion. The light microscopic changes of Group DM were consistent with SEM findings. The total number of osteoclasts was fewer at 1d and larger at 3d and 5d in Group DM. Osteoclasts at the upper region of alveolar bone increased from 1d to 5d in Group N, although the number of osteoclasts did not show a significant change in Group DM. At the middle to lower portion of alveolar bone, the number of osteoclast was significantly fewer at 1d, larger at 3d and 5d in Group DM. In experiment 2, the col with ulceration and necrosis did not show bacterial deposits or sequester, suggesting the intimate relation between bacterial infection and sequestration. The present study suggests that food impaction and subsequent mechanical compression to the col could induce various damages of periodontal tissue, including sequester formation, and elaborate plaque control at the initial stage of food impaction could prevent sequester formation and protect the height of alveolar bone.

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Peritendinous adhesions are serious complications after surgical repair of tendons and can lead to poor functional outcome. In the present study, the tensile strength of repaired tendons was measured biomechanically in two groups using a rabbit Achilles tendon model, and the effects of Adcon gel on peritendinous adhesions and tendon healing were examined by means of histological and mechanical analyses. In the treatment group, the Achilles tendon was transected, followed by a primary repair using a modified Kessler technique, and Adcon gel was injected between the tendon and skin of the right leg. The same operation was done for the control group, and 1 mL of normal saline solution was applied locally in a similar fashion. The experimental protocols were approved by the local animal ethics committee. Microscopic evidence of the formation of adhesions and of inflammation was less in the treatment group than in the control group. There was no significant difference in the tensile load necessary to rupture the repaired tendons between the two groups. Adcon gel reduced the peritendinous adhesions histologically without impairing tendon healing, as determined with mechanical analyses. The use of Adcon gel may provide a simple means of preventing of postoperative peritendinous adhesions, thereby offering a beneficial effect on tendon repair.

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The aim of this study was to investigate the relationship between the different kinds of leukoaraiosis (LA) and carotid atherosclerosis (AS) plaques. A total of 208 LA patients were divided into three groups, namely, circumventricular (Group I, n=68), subcortex (Group II, n=66), and mixed types (Group III, n=74). The AS plaques and stenosis of the carotid were detected using color Doppler flow imaging and the magnetic resonance images of patients, respectively. Among the patients enrolled in this study, 67.79% (141/208) had AS plaques, 24.04% of which was detected in Group II (50/66), 25.96% from Group III (54/74), and 17.79% from Group I (37/68), with significant difference among all groups. By contrast, the score of the stable plaques was identical, with all the AS plaques scoring under three grades. The Grades I/II/III plaques of the subjects in Group I were 45/40/47, respectively; Group II had 20/40/47; and Group III had 20/31/34. The Grades I/II/III plaques among the 52 subjects with cortid stenosis (50%) were 15/19/18 without any differences. The carotid AS plaque is one of the risk factors of LA and the fragments of vulnerable plaques related to leukoaraiosis.

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The aim of the present study was to clarify the shape of the pulp chamber and the three-dimensional positional relationship between the contour of the crown and pulp chamber using a micro-computed tomography system (micro-CT) for restorations of mandibular second deciduous molars without pulp exposure, and to evaluate quantitatively the thickness of the hard tissue surrounding each pulp chamber. Samples were caries-free mandibular second deciduous molars of the deciduous and mixed dentition periods (10 each) extracted from the dry skulls of Indian children. Micro-CT images of the crowns were taken. Horizontal two-dimensional slice data were then stacked to construct three-dimensional images, and the shape of the pulp chamber and positional relationship between the contour of the crown and pulp chamber were observed from various directions. Then, the volume ratio of the pulp chamber relative to the crown contour and the distance from the crown surface of each pulp horn (hard tissue thickness) were investigated to evaluate the characteristics of the deciduous and mixed dentition periods objectively. The results showed that the mesiobuccal and mesiolingual pulp horns of deciduous dentition were most pointed, and approximately the same height. The pulp horn was lower and rounder in the mixed dentition period than in the deciduous dentition period. The pulp chamber shifted to the mesial side of the crown contour in both the deciduous and mixed dentition periods. These findings suggest that care should be exercised to avoid exposure of the mesial pulp horn during cavity preparation for deciduous mandibular second molars, especially during the deciduous dentition period.

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To produce a large-sized regenerative joint by the conjugation of small elements combining artificial bone with tissue engineering cartilage, we made small beta tricalcium phosphate (β-TCP)-hexagonal columns (each side: 2 mm, height: 1 cm) as a substitution of subchondral bone, and attempted to achieve mutual bonding of those columns. A large number of cell sheets was produced from mesenchymal stem cells (MSCs) using N-Isopropylacrylamide (NIPPAM)-coated culture dishes. Those cell sheets were dripped onto the lateral surface of a β-TCP-hexagonal column. A pair of the columns was combined side-to-side with each other and were then cultured in osteogenic medium. After 3 weeks of culture, the matrix production-promoting stimulation led to bonding of the two columns, and they were not readily separated by lifting one column using forceps. Not only a pair of those columns, but also three or five, were strongly conjugated, and the columns could be lifted as a single mass. Such in vitro bonding of hexagonal columns of β-TCP utilizing MSCs can support the increase in size of regenerative joints and would enable widening of clinical indications for tissue engineering.

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Craniofacial growth is influenced by the interaction of muscle and bone tissues. The medial pterygoid (MP) is one of the muscles of mastication attached to the mandible. The purpose of the study was to investigate the relation between the MP and mandible during embryogenesis. Specimens were prepared from fifty fetal mice at embryonic day (ED) 12.5, 13.5, 14.5 and 15.5. Slides were stained with hematoxylin and eosin (H&E) and observed under the light microscope. Immunohistochemistry using desmin, a muscle specific marker, as well as vimentin, a mesenchymal specific marker, were also carried out. Desmin and vimentin mRNA expressions were analyzed by quantitative polymerase chain reaction. Results showed that at ED 12.5, the MP and lateral pterygoid (LP) and tensor veli palatine (TVP) were adjacent to one another. Over time, the LP moved more externally while the TVP moved more medially. At ED 13.5, the mandible started to form while the MP moved towards the developing mandible. At ED 14.5, the palatine shelves were also seen in a horizontal position. Over time, desmin localization was observed at myotendinous junctions in between the MP and Meckel’s cartilage (MC) as well as in between the MP and mandible and finally in the center of the muscle. The increase in the expression was supported by desmin mRNA expression. Vimentin was widely distributed in mesenchymal cells with no significant difference among the stages. The results suggest that although the muscles of mastication were still immature, the premature contraction of the MP and the positional relationship provide a dynamic change between the development growth of the mandible and the start of the fusion of the secondary palate.

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Bone allografts are commonly used for bone regeneration. The aim of this study was evaluate the efficacy of a freeze dried bone matrix (FDBM) in critical size defect (CZD) rat calvaria. Eighteen Wistar female rats (body weight 150 ± 50 g) with CZD (5mm) were divided in two groups: group 1, using freeze dried bone matrix; and group 2, only with coagulum. All samples were evaluated on the 1st, 3rd and 6th weeks post-surgery by soft X-ray, histological and histometric studies. Soft X-ray results showed a radiolucent image with many irregular radiopaque areas. Histologically, bone regeneration was initiated from the 3rd week, when a thin layer of new woven bone could be seen adjacent to the matrix. At the 6th week, lamellar bone covered over half (61.8 %) of the defect area. The lack of FDBM resorption allowed its incorporation to the new regenerated bone. This behavior is important in circumstances where it is necessary not only to stimulate bone regeneration but also increase the volume in affected areas, such as during the placement of dental implants. The results obtained in this research are encouraging for the use of freeze dried bone matrix as a bone graft material.

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For dental implant treatment, it is important to assess the general bone condition. Using multi-slice CT scans, we assessed the relationships between the bone mineral densities (BMDs) of the cervical and lumbar vertebrae in postmenopausal women to see if such data might be useful for imaging-based diagnosis prior to dental implant treatment. Thirty postmenopausal women were enrolled in this investigation, and their third cervical vertebrae were scanned for BMD using multi-slice computed tomography (CT) while the lumbar vertebrae were measured using dual energy X-ray absorptiometry, after which the percentage of the young adult mean (YAM) was calculated. The correlations between the BMD of the cervical vertebra and percentage of YAM were analyzed. The mean BMD of the cervical vertebra was 255 mg/cm³ HA (s.d.: 28.8) in the normal group, 233 mg/cm³ HA (s.d.: 44.3) in the osteopenic group, and 178 mg/cm³ HA (s.d.: 35.9) in the osteoporosis group. A significant difference was observed between the normal and osteoporosis groups, and between the osteopenic and osteoporosis groups. A correlation (r = 0.705) was observed between the BMD of the cervical vertebrae and percentage of YAM of the lumbar vertebrae. The BMD of the third cervical vertebrae obtained from multi-slice CT images might be applicable in dental implant treatment to evaluate the influence of the general bone condition.

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The medical use of ozone has been based on its antibacterial and oxidative characteristics. Currently ozone is being discussed in dentistry as a possible alternative oral antiseptic agent. In this study, we examined the hemostatic effect of water and gel contains aqueous ozone in animal testing. The mean of bleeding time using ozonated water and ozonated gel were observed for significant difference compared with no treatment. 0.5 ppm diluted ozonated water shortened bleeding time the same as 4.0 ppm ozonated water. These results suggest that ozonated water and gel which contains aqueous ozone show hemostatic ability which is almost equal to the Bosmin solution and Liquid Thrombin.

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To creat a preliminary database in accordance with McNamara’s cephalometric analysis on lateral view of 3D CT cephalometric of the population from northeast China. Lateral 3D CT scans from 98 adults with Class I normal occlusal relationship from northeast China were collected. The coordinates of landmark points including the subspinale, supramental, upper incisor, pognion etc, were measured with the Frankfort plane and a vertical straight line though the nasion being the origin of reference. Measurements were taken with respect to effective maxillary and mandibular lengths, middle anterior and anterior face heights, and lower anterior length. The data were then analyzed with the data in McNamara’s cephalometric analysis. Our lateral view of 3D CT based McNamara’s cephalometric data indicate that subspinale locate antierior to the vertical line, but there is no significant difference between male and female. Statistical differences exist between male and female on effective maxillary length, effective mandibular length, 1/3 height of middle face, 1/3 height of lower face and lower face length. The present study built the first preliminary data of McNamara’s cephalometric analysis on lateral view of 3D CT cephalometric of the population from northeast China. These data would be a useful reference for diagnosis and treatment plan of dental facial deformities, however it will take time to accumulate a large sample to establish a representative database.

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Periodontitis is characterized by alveolar bone resorption and loss of attachment. Recently, many induced periodontitis animal models have been developed to mimic alveolar bone resorption, but each model has a number of disadvantages. Periodontitis-inducing procedures should be simple and reproducible. Therefore, with the aim of establishing an experimental mouse model of periodontitis, we induced subgingival plaque accumulation in eight-week-old male C57BL/6 wild-type mice by placing an orthodontic ligature wire around the contact point between the left maxillary first and second molars. Maxillae were collected at four and eight weeks after ligature placement, and alveolar bone between the left molars (test maxillae) was compared with that between the right molars (control maxillae). Micro-computed tomography and pathological analysis were then performed to examine the degree of alveolar bone resorption. Alveolar bone resorption was significant in the test maxillae compared with the controls. In addition, the ligature wire was not found to affect the periodontal tissue. The induction of alveolar bone resorption was likely due to the direct mechanical impact (mechanical irritation of gingiva) of the wire ligature. These findings suggest that placement of the ligature wire around the contact point between teeth successfully induced alveolar bone resorption. Furthermore, use of the ligature wire removed the need to induce alveolar bone resorption by using an impacted wire ligature to create mechanical stress. Therefore, the present report provides a new animal model of periodontitis.

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Mandibular resection has been associated with a poor health-related quality of life (HRQOL), particularly in young patients with free fibula flap requiring defect reconstruction.¡¡The purpose of our study was to evaluate HRQOL of young patients who have had mandibular resections of huge ameloblastoma and free fibula flap reconstruction. The present study assessed 32 young patients who had undergone immediate mandible reconstruction with free fibula flap for huge ameloblastoma using the University of Washington Quality of Life (UW-QOL) Questionnaire and 49-item Oral Health Impact Profile (OHIP-49). Thirty-two of the forty-seven questionnaires were returned (68.08%). Of the 12 disease-specific domains on the UW-QOL, the best 3 scores from the patients were for shoulder, pain and taste, and the worst 3 scores were for chewing, anxiety and mood. On the OHIP-49, the lowest-scoring domain was physical pain, followed by handicap and social disability. A significant effect was found on the HRQOL of young patients with huge ameloblastoma who had undergone immediate mandible reconstruction with free fibula

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Uncertainty exists regarding sex-, age- and tooth-related cortical and trabecular bone quantity tendencies at the mandibular first molar, a frequent implant recipient site in partially edentulous patients with missing molars. We assessed these tendencies for the mandibular first molar by using computed tomography in patients missing the first molar on one side. Eighty-two subjects were assessed. Cortical and trabecular bones were quantified using computed tomography image reformatting software on a cross-sectional image, including the site of the mandibular first molars on sides with and without the first molar. Bone quantity associations with age and between the sides with and without the first molar were evaluated. Bone quantities were compared according to sex and between the two sides. Great interindividual variations between cortical and trabecular bone quantities were seen in both sexes and on the two sides. Although no sex-related or age-related difference in trabecular bone quantity existed, men demonstrated a greater cortical bone quantity than women; women, but not men, exhibited an age-related decline in cortical bone quantity. Bilateral symmetry of both bone quantities appeared only in women. Cortical bone quantity did not differ between the two sides in either sex, while trabecular bone quantity differed; the side without the first molar had greater values than that with it in women and, to a lesser extent, in men. A computed tomography analysis distinctively measured cortical and trabecular bone quantities and unveiled their sex-related differences in a clinical situation, as specifically designed in this study.

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Tissue engineering is a rapidly evolving field involved in the restoration of functions and esthetics of tissues after surgery. Utilizing the oral mucosa as a source of tissue-engineered epithelial cell sheets is beneficial due to the fast healing rate and regenerative capability of the tissue. This study investigated the effect of mesenchymal fibroblasts on epithelial cells taken from rabbit oral mucosa. Rabbit oral epithelial cells were cultured on collagen gels both with oral mucosa fibroblasts (OMFs+) and without (OMFs-). Samples were stained with hematoxylin and eosin and observed under a light microscope. The expressions of cytoskeletal, adhesion, basement membrane and junctional complex as well as cell proliferation protein markers were also determined through immunohistochemistry. Results showed that the OS+ group had epithelial cell sheets that were better developed than those of the OMFs- group. Moreover, cytoskeletal, adhesion, basement membrane, junctional complex and cell proliferation markers were more intensely expressed by epithelial cells in the OMFs+ group than in the OMFs- group, and the expression increased over time. Immunohistochemistry demonstrated how stem cells taken from the oral mucosa contributed to the expression of various cytokines indispensable for the growth of the cells. The epithelial-mesenchymal interaction between the keratinocytes and fibroblasts accounts for the architecture of the epithelial cell sheets.

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