We examined the effect of occlusal force on morphology of the mandibular molar region. The subjects were 20 males with individual normal occlusion. The bite force was measured with an occlusal force-meter using pressure sensitive film. The morphology of the mandibular molar region was determined with dental cone beam CT. Slice images across the apex of mesial root of the mandibular first molar were used to measure of (1) the widths of the mandibular molar region across the apex, (2) the widths of the mandibular molar region at the midpoint between the apex and the nadir of the mandibular bone, (3) the widths of the cortical bone in the mandibular molar region across the apex, (4) the widths of the mandibular cortical bone at the midpoint between the apex and nadir of the mandibular bone, (5) the distance between the apex and the lingual cortical bone surface, and (6) the distance between the apex and the buccal cortical bone surface. Correlation analysis was conducted between the occlusal force and these measurements. We investigated the positive correlation between occlusal force and the FH-plane-based width of the mandibular bone across the apex and the width of the mandibular bone at the midpoint between the apex and nadir of the mandibular bone. We found that the mandibular inter molar width increased with increases in occlusal force.

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We devised a method of fabricating copings for all-ceramic crowns in a short time that does not require specific equipment or duplicate models, and evaluated its possible clinical application. We reduced the working time and improved the fit of the copings. However, we were unable to improve the strength of the copings. In this study, to improve the fit of the copings, we evaluated the effect on the fit of drying the slips with a dryer and with air drying, after sintering and after infiltration, during production of the copings. We found that the fit of the copings with air drying averaged 190μm while the fit with the dryer averaged 37μm after sintering. After infiltration, the fit of the copings with air drying averaged 298μm while the fit with a dryer averaged 212μm. Fit of the coping with the dryer, was better than the fit of the coping with air drying at the 1% significance level after sintering. The drying process after infiltration did not significantly affect the fit. Therefore the fit of the coping after sintering was improved by using a dryer to dry the slip. The fit of the copings was degraded by the infiltration.

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It has been reported that a titanium oxide nanotube (TNT) has a specific tube structure and diversity of the titanium crystals, as well as superior photocatalytic capacity and a physicochemical function. We did basic research on TNT. We measured its number of radicals and its changes in methylene-blue (MB) solution to evaluate its photocatalytic capacity. Also, we examined its effect on tooth whitening. We found that the TNT produced radicals such as TiO_2, reduced the concentration of MB, and bleached stained apatite pellets when combined with a low concentration H_2O_2.

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We evaluated the influence of the combined use of dentin desensitizer and a tooth whitening agent on bleaching effects. Bovine teeth were immersed in a pigmentation liquid to discolor the specimens. The color was measured before and after the whitening using TiONTM in Office four times every day for seven days in total (control group). After each bleaching treatment, MS coat F, Nanoseal, or Teethmate Desensitizer were applied to the specimens. This group was referred to as the application during bleaching group. After bleaching treatments, another group of specimens were immersed in a pigmentation liquid, desensitizer was applied, and color measurements were done every 7 days. This group was referred to as the application of desensitizer after bleaching group. Because dentin desensitizer applied to the hydroxyapatite had no effect on whitening, we concluded that there is no problem with their combined use.

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Peripheral injury to sensory nerves causes glial responses at the primary nerve terminals of the ascending sensory pathways in the central nervous system. During these responses, microglia alter neural activityin the primary sensory nuclei. We investigated the distribution of microglia in the rostral NST (rNST) after inferior alveolar nerve (IAN) transection. IAN transection was done in seven-week old Sprague-Dawley rats at the ascending ramus under pentobarbital anesthesia. One week after the IAN transection, microglia-specific protein Iba1-immunoreactive (ir) cells were labeled with fluorescent immunohistochemistry in brainstem slices that included the NST. The glialresponse in the NST was significantly higher in the rostral-lateral region in the lAN-transected rats in comparison with the same region in the sham rats. This result suggests taste disruption after dental surgery may be attributed to the responses of rNST microglia resulting from IAN damage.

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Temporary anchorage devices (TAD) have been used for tooth intrusion and distal movement in recent years, and their clinical efficacy is well established. One of the advantages of using TAD in orthodontics is reduced treatment time. A three-dimensional model of the maxilla was constructed to evaluate the utility of TAD, and stress change affecting the alveolar bone after the extraction of the first premolar was investigated using the three-dimensional finite element method. An outline of the model was fabricated from CT image data with extracted contours using the stress analysis software MECHANICAL FINDER version 6.2, followed by the construction of a three-dimensional maxillary model and fabrication of an extracted maxillary first premolar model. Four chronological models, immediately after tooth extraction, and after 1, 3, and 6 months, were fabricated by changing the CT values of the extracted area based on this model. A TAD was constructed in the mesial area of the upper first molar using the SolidWorks software. The upper first molar was constrained, and the upper canine was pulled in a distal direction towards a constructed anchor at 1 N to analyze stress changes affecting the alveolar bone in the region of the extracted tooth. Stress affecting the alveolar bone in the extracted region peaked immediately after tooth extraction, gradually decreased between 1 and 6 months, and reached a minimum at 6 months. Similarly, the amount of tooth displacement peaked immediately after tooth extraction, gradually decreased between 1 and 6 months, and reached a minimum at 6 months. These results suggest that when using TAD it is more beneficial to apply tractive force soon after tooth extraction for distal tooth movement.

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The purpose of this study was to evaluate the Chondrocyte differentiation potential of dedifferentiated fat cells (DFATs) and adipose stem cells (ASCs) from the buccal fat pad (BFP) in an atelocollagen sponge. The gene expression levels of Chondrocyte differentiation markers were higher in DFATs than in ASCs cultured for 14 and 21 days, whereas protein expression levels were higher in DFATs at all time points tested for aggrecan. Additionally, the levels of the embryonic stem cell markers were higher in DFATs than in ASCs at 72 h. The extracellular matrix of both the cultured ASCs and DFATs was Alcianblue-positive and was also aggrecan-positive. Therefore, we think that BFP-derived DFATs are an ideal cell source for cartilage tissue engineering.

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We evaluated the mechanical properties and bond strength of commercially available adhesives used with ortho-dontic brackets on enamel. Debonding of brackets must be done gently so as not to create pain or injury to the enamel. Three commercially available adhesive resin cements, Super-Bond (SB), Beauty Ortho Bond (BO) and Rely X^<TM> Unicem 2 Automix (UN) were used. Two self-etching primer adhesive systems, Beauty Ortho Bond (BO) and Rely X^<TM> Unicem 2 Automix (UN) were used. The bond strength to enamel of SB placed in 37℃ water was 18.8 Mpa after one day, 16.6 Mpa after 6 months, and 19.2 Mpa after one year. The bond strength to enamel of BO in 37℃ water was 11.6 Mpa after one day, 8.9 Mpa after six months, and 13.6 Mpa after one year. The bond strength to enamel of UN in 37℃ water was 5.8 Mpa after one day, 4.0 Mpa after six months, and 13.6 Mpa after one year. The adhesives showed excellent bond strength of approximately 6〜15 Mpa with both precious alloy brackets after 10,000 thermocycles consisting of alternately immersing the specimens in 5℃ and 55℃ water for one minute each. We concluded that the application of adhesives greatly improvied the bond strength of the resin cements.

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The macrophage cell line RAW264.7 is differentiated into osteoclasts by stimulation of receptor activator of nuclear factor κB ligand (RANKL). We examined the coordinated effect of IL-17 AandlL-27 on osteoclast differentiation of RANKL-stimulated RAW264.7 cells. The coordinated effect of IL-17 A and IL-27 decreased the number of multinuclear TRAP-positive cells, which are induced by RANKL. Phosphorylation of JNK, which was markedly induced by RANKL stimulation, was inhibited by the coordinated effect of IL-17 A and IL-27. These results suggest that the reduction of JNK phosphorylation, which is induced by the coordinated effect of IL-17 A and IL-27, may be a factor that suppresses the differentiation of osteoclast precursors into osteoclasts.

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Diabetes mellitus (DM) is one of the main etiology/risk factors of periodontal disease, and is intimately involved with the treatment of the disease. Although it has been reported that high blood glucose mediates the proliferation, differentiation and production of inflammatory cytokines from mesenchymal cells, there have been few reports on the effect of DM on periodontal regenerative therapy. We examined the biological effect of high blood glucose on the bone marrow mesenchymal stem cells (BMMSC) of Goto-Kakizaki (GK) rats. Cell culture experiments were performed on the BMMSC of the animals. The biological effects of the high glucose condition on the BMMSC was determined at four concentrations of culture solution by examining cell proliferation, cell differentiation and the production of inflammatory cytokines. We found that highly-concentrated glucose promotes cell proliferation and inhibits hard tissue differentiation and calcification in the BMMSC of GK rats. Differentiation depended on production of inflammatory cytokines like IL-6. The data suggests that a high glucose condition promotes cell proliferation while inhibiting hard tissue differentiation and calcification because of the inflammation by periodontal regeneration.

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We used ultrasonography to examine how insertion of a mandibular bilateral extension denture affected tongue movements during mastication. We selected 10 young dentate individuals, 10 older dentate individuals, 10 people with complete dentures, and 6 others who had mandibular bilateral extension dentures. Height differences between the left and right sides of the tongue were compared during mastication. The results suggested that tongue movement during mastication was lower where occlusal support had been established.

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Few studies have investigated bone healing of the extraction socket in osteoporosis. We evaluated the bone response after mandibular incisor extraction in rats with osteoporosis using titanium alloy implants in vitro and in vivo. Ovariectomy (OVX) or control operations were performed at 9 weeks of age. In vitro measurements were done with titanium alloy disks of the alkaline phosphate (ALP) activity after 7 and 14 days, osteocalcin (OCN) production after 21 and 28 days, and calcium deposition after 21 and 28 days. The titanium alloy screws were placed in the mandibular extraction sites and the animal body weight was examined at three-week intervals. At 3, 6 and 9 weeks post-insertion, histological observations were performed. At all measurement points, cells of the control group show significantly more ALP activity, OCN production and calcium deposition than did cells of the OVX group. The healing process of the extraction socket after insertion of a titanium screw was different between the controls and the OVX animals. Histopathologic examination showed that formation of new bone in the extraction socket was markedly inhibited in the ovariectomized rats. We found that osteoporosis affects socket healing after the extraction in ovariectomized rat mandibular incisors. This should be taken into consideration when doing implants in patients with osteoporosis.

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One possible complication of tracheal intubation is injury to the anterior teeth by the laryngoscope blade. We measured pressure where the anterior teeth contacted the blade, and investigated differences in this pressure using six different laryngoscope blades (German design, US design, UK design, English Channel type, reduced flange type and flangeless type). We used a mannequin for intubation training (Laerdal Airway Management Trainer; Laerdal Medical, Tokyo, Japan) and a German bite pressure meter (Ninon Kohden Corporation, Tokyo, Japan). Each laryngoscope blade was used 30 times to perform direct laryngoscopic exposure, and we measured the maximum pressure of the laryngoscope blade on the contact site of the anterior tooth when a Cormack Grade I larynx field of vision had been secured. Because the field of vision of the larynx could be obtained with the flangeless type laryngoscope blade without any contact with the anterior teeth, it was excluded from this analysis. Statistical analysis performed using multiple comparisons (Tukey-Kramer method, p<0.05) showed that contact pressure with the reduced flange type laryngoscope was significantly smaller than with the other types. These results suggest that laryngoscopes with a narrow blade width cause less pressure and therefore a smaller burden on the contact site of the anterior teeth.

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Strontium (Sr) ions are often used for treatment of bone disease. However, it is unclear whether they are applicable for cartilage regeneration therapy using adipose-derived stem cells (ADSCs). We demonstrated in this study that the Sr ions contained in a chondrogenic medium (CM) enhanced the chondrogenic differentiation for ADSCs in vitro up to day 14. In addition, the media caused no elevation in osteoblastic, hypertrophic chondrogenic, or adipogenic differentiation. We concluded that Sr supplementation in CM might be useful for preparing ADSCs-derived chondrocytes for chondrogenic regeneration therapy in cleft lip and palate cases.

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We examined morphological and functional changes induced with the use of a modified Herbst appliance to promote condylar cartilage growth and thereby induce forward remodeling of the glenoid fossa. The study included 7 females between 18 and 20 years of age with Angle Class U malocclusion and an ANS angle between 4.5° and 7.5°. The treatment time with this appliance was 9 months. Lateral cephalometric radiographs and computed tomography images were taken to evaluate morphological changes. The results suggest that Herbst treatment promoted condylar growth and fossa remodeling.

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Tobacco smoke is a complex mixture of numerous components. We have shown that a comprehensive mixture of tobacco smoke components (TSCs) attenuated bone resorption through osteoclastogenesis inhibition, thereby retarding experimental tooth movement in a rat model. Histological evaluation disclosed that the attenuation was partially due to the decrease of the number of TRAP-positive osteoclastic cells in the bone marrow cavity. An in vitro study indicated that TSCs seemed to more influence preosteoclasts than osteoblasts. These results may aid in formulating predictable treatments for orthodontics and bone diseases.

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