An accurate evaluation of tooth size and tooth size discrepancy is critically important in orthodontic diagnosis and treatment planning. The purpose of this study was to establish a new method to measure and assess tooth size and tooth size discrepancy with accuracy and reproducibility, named as circumferential tooth size (CFT), circumferential anterior tooth size ratio (CAR), circumferential overall tooth size ratio (COR) respectively. Total 128 dental models were scanned via Hirox digital stereomicroscope for the fabrication of the digital models. Dental models were selected on the basis of inclusion criteria. All the measurements were obtained with the accuracy of 0.1×10^-6 mm; the mean and the SD for the CFT, CAR and COR were calculated. The developed norms for the CFT, demonstrated significantly greater values for males in relation to females. More precisely, there were statistically significant differences observed in different variables (*p≦0.05 to ***p≦0.001). CAR and COR ratio show slight greater value for males without any statistically significant differences. The findings provide valuable information that CFT cover the tooth size in all dimensional aspects. For the prediction of ideal occlusion to be achieved at the finishing stage, orthodontist needs to evaluate CAR and COR ratios via proposed method.

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Recent studies have suggested that a balance between Wnt and bone morphogenetic protein (BMP) output may be a key factor for regulatory networks involved in bone regeneration. Here we report that Wnt inhibitors coordinately regulate osteoblastic differentiation induced by BMPs of human periodontal ligament cell. Human periodontal ligament (HPDL) cells were stimulated with BMP2/7, Dexamethasone (Dex), or a combination of these reagents. After treatment, we analyzed the phosphorylated Smad1/5 and osteoblast differentiation markers. Specific antagonists such as Dickkopfs (Dkk1, Dkk2) , secreted Frizzled-related proteins (SFRP1,SFRP2), and sclerostin(SOST) which are believed to play important roles in osteoblast differentiations were also examined by quantitative RT-PCR. BMP2/7 treatment increased ALP activity modestly, and the combination of BMP2/7 with Dex greatly enhanced ALP activity. SOST expression increased sharply following BMP2/7 treatment; however, adding BMP2/7 and Dex drastically reversed this increase in SOST. BMP2/7 and Dex treatment synergistically decreased DKK2 and sFRP2 expression. In contrast, BMP2/7 and Dex had a significant inductive effect on DKK1 and sFRP1 expression. BMP2/7 treatment resulted in Smad1/5 phosphorylation, but adding Dex did not induce p-Smad1/5. However, BMP2/7-induced Smad1/5 phosphorylation was inhibited in the combined treatment group. These opposite trends support the previous reports showing mutual antagonism between DKK1 and DKK2 or sFRP1 and sFRP2. In conclusion, well-balanced Wnt inhibitors may be crucial for bone tissue homeostasis.

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Dysregulation of growth and inflammatory mediators might contribute to defective tissue homeostasis and healing, as commonly observed in sedentary lifestyles and in conditions such as diabetes mellitus and periodontitis. Periodontitis is an inflammatory disease characterized by extensive bone resorption. Sodium fluoride (NaF) causes proliferation and differentiation, and modulates the activity of growth factors. In this study, we investigated the effects of NaF on insulin-like growth factor (IGF) 1 and 2 in Goto-Kakizaki (GK) rats, a spontaneous model of type 2 diabetes induced by Porphyromonas gingivalis, an important colonizer of the oral cavity that has been implicated in periodontitis. NaF strongly inhibited the P. gingivalis-induced alveolar bone loss. That effect was accompanied by decreased levels of TNF-α, IL-1β, and RM4, which were up-regulated in P. gingivalis-induced diabetes model. Consistent with the anti-inflammatory effect, NaF inhibited osteoclast markers, the receptor activator of nuclear factor kappa B ligand (RANKL) and Cathepsin K protein expression. IGF-1, -2 was strongly expressed by periodontal ligament, fibroblasts, particularly those in areas close to cementum and bone surfaces in NaF-treated groups. In the periodontal ligament, strong staining was noted in the fiber bundles inserting into alveolar bone and cementum. Our findings suggest the mechanism of IGF signaling by which NaF alters periodontal tissue repair in type 2 diabetes.

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The green spotted pufferfish (Tetraodon nigroviridis) is a brackish tropical fish whose draft genomic sequence has been published. Its genome is the smallest among vertebrates, and genes account for a high rate of the genome. In addition, many genes have a specific function. Because of these characteristics, the green spotted pufferfish is used as a model animal for genetics. Therefore, this species is likely to be used for basic and clinical studies, similarly to zebrafish and medaka, but no study on its jaw bone and tooth structures has been reported. In this study, we observed the jaw and tooth structures of green spotted pufferfish with an about 3-cm body length using electron and light microscopes. In its jaws, the bilateral bones were joined through finger-like processes at the middle on both upper and lower sides. Several tooth germs in different developmental stages were vertically arranged in the jaw bone, which may have a rod-like morphology in the mesio-distal direction. Soft tissue was present between the tooth germs. A protrusion containing tooth germs was present on the bilateral lingual sides in the upper and lower jaw bones, but the position of this protrusion was lower than the jaw bone apex. Based on these findings, the green spotted pufferfish may be used as an experimental animal useful for studies on tooth morphogenesis.

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Developmental studies indicate the Wnt/ β-catenin pathway biphasically regulates tissue differentiation. Bone morphogenetic protein (BMP) and Wnt signaling reported function in osteoblast differentiation, but few studies have investigated these complex mechanisms. We hypothesized that Wnt/β-catenin signaling acts, either promoting or inhibiting osteogenesis of human periodontal ligament (HPDL) cells depending on times of treatment of Wnt3A. HPDL cells were treated with single or repeated administration (12- or 24-h intervals) of 10 ng/ml of Wnt3A and cultured for 3 days. Single Wnt3A administration increased alkaline phosphatase (ALP) activity. Conversely, repeated Wnt3A administration significantly decreased the expression of osteoblast marker genes. Single Wnt3A administration resulted in Smad1/5 and Akt phosphorylation; however, repeated Wnt3A administration inhibited it. BMP2/7 or IGF-1 treatment was sufficient to reverse the inhibitory effects of repeated Wnt3A treatment. Single administration of a glycogen synthase kinase 3 inhibitors, CHIR99021, increased ALP expression, but repeated CHIR99021 administration significantly decreased ALP expression and ALP activity compared with single administration. These findings suggest that repeated activation of Wnt signaling inhibits osteoblast differentiation by suppressing the BMP2/7–Smad1/5 and phosphatidylinositide 3-kinase (PI3K) /Akt pathways in HPDL cells. This indicated that crosstalk between the Wnt, Smad1/5, and PI3K/Akt pathways is important for osteoblastic differentiation of HPDL cells.

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The aim of the present study was to evaluate the bone adaptation of fibronectin-immobilized titanium implants in vivo using a tresyl chloride-activated method in implantation experiments with rabbit tibiae. Cylindrical pure titanium (3.5 mm in diameter and 7 mm in height) was treated with tresyl chloride (2,2,2-trifluoroethanesulfonyl chloride, CF₃CH₂SO₂Cl) and then coupled with fibronectin to give fibronectin-immobilized cylindrical titanium (Fn/Ti) implants. Non-treated cylindrical titanium (Ti) implants were used as a control. Ti and Fn/Ti implants were implanted into bone defects in the tibiae of rabbits. The implants were excised 12 weeks later and non-decalcified thin sections were prepared. After staining each section with methylene blue and basic fuchsin, the implant-bone interface was histologically evaluated and the bone-to-implant contact ratio (BIC) and bone mass (BM) were histomorphometrically calculated using an image analysis system. A larger amount of new bone formation was recognized for Fn/Ti implants and histomorphometrical evaluations showed that BIC and BM were significantly higher for Fn/Ti implants than for Ti implants. Fn/Ti implants also showed better bone adaptation. These results demonstrated that the immobilization of fibronectin onto cylindrical titanium implants effectively enhanced bone regeneration around implants.

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This study aimed to compare the response of peri-implant tissue surrounding hydroxyapatite-coated titanium (HA) implants and anodic oxidized titanium (AnO) implants, as well as associated ligature-induced peri-implantitis. The third and fourth premolars (P3, P4) of the mandible were extracted in five beagle dogs. After 2 months, 10 dental implants with different surfaces (HA/AnO) were inserted into the mandible in five beagle dogs. A plaque control program was maintained until the second-stage surgery. Three months after implantation, a healing-cap connection was performed, and silk ligatures were placed in the submarginal position around the neck of the implants to induce peri-implantitis. Macroscopic evaluations including modified plaque index (mPI), modified gingival index (mGI), and probing depth (PD), and radiographic evaluations including dental radiography and multislice computed tomography (MSCT) were conducted for 24 weeks following ligature placement. Bone loss around the implant was evaluated according to the radiolucent area on dental radiographic images and the hyperpermeability area on MSCT images. All macroscopic parameters except PD exhibited a consistent increase for all implants. Over the course of the study, bone loss associated with the HA implant was greater than losses with the AnO implant. Following evaluation of dental radiographs at 20 and 24 weeks after ligature placement, a significant difference was detected between the HA and AnO implants (P < 0.05). The results suggested that the resistance of the HA implant to peri-implantitis was inferior to that of the AnO implant.

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This histopathological study used streptozotocin (STZ)-induced diabetic rats to investigate insulin administration in conjunction with an antibacterial irrigation of chlorhexidine gluconate solution and its effect on the disturbance of periodontal tissue and destruction of alveolar bone induced by mechanical compression at the col due to food impaction. The experimental animals were divided into normal rats (Group N) and STZ-induced diabetes mellitus (DM) rats. Mechanical compression was done by insertion of a gutta-percha point (GP). The diabetic rats were further divided into Group (DM+Ins), in which insulin was administered, and into Group (DM+Chlo), in which 0.2% chlorhexidine gluconate solution was used for bactericidal irrigation. Histological comparisons of the destructive process and reparative changes of the periodontal tissue were performed at 1, 3, 7 and 14 days after the col compression.
The antibacterial irrigation effects caused by chlorhexidine gluconate solution were considered to be low during the early stages. However, since there was no sequestrum formation at the alveolar crest at 7 days after the col compression, reparative changes of periodontal tissue were able to progress. These results suggest that there was a constant antibacterial effect after the chlorhexidine gluconate solution irrigation. Even so, the use of only chlorhexidine gluconate solution in cases with very destructive changes or in cases with persistent mechanical compression, made it difficult to perform a successful treatment of the disturbance of the periodontal tissue. Results for Group (DM+Ins) were better than those for Group (DM+Chlo) with regard to the inhibition of bacterial contaminant at the food impaction area, alleviation, and improvement of the healing process after disturbance in the periodontal tissue. The persistent use of 0.2 % chlorhexidine gluconate solution did appear to lead to a constant effect on the bacteria. Therefore, when treating a disturbance of the periodontal tissue due to food impaction in the diabetic state, the first step should include the administration of insulin in order to improve the diabetic state.

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Orthodontic anchor screws, which made from titanium are widely used as anchorage units in orthodontic treatment. However, there are some problems, including dropout during treatment and the invasive nature of screw removal. An orthodontic anchor screw, in which the main component is a bioabsorbable material is therefore sought. We investigated the biological evaluation of a prototype material composed of polyglycolic acid (PGA) and hydroxyapatite (HAp). Five types of PGA/HAp composites were examined. The HAp compound ratios by weight were 0, 5, 10, 30 and 50 %. We examined the effects of the PGA/HAp components on the gene and protein expression of collagen type 1 (COL-1), alkaline phosphatase (ALP) and osteocalcin (OCN) from mouse osteoblasts (MC3T3-E1) in vitro by real-time a PCR and an ELISA. Furthermore, we evaluated the osteoinductive potential in vivo, in a rat calvarial defect model after subjecting samples to a μ-CT image analysis. COL-1 and ALP production peaked on day 7, and increased dependent on the concentration of HAp. OCN production also increased in a dose- and time dependent manner up to day 10 in vitro. In the in vivo study, μ-CT image analyses showed that newly formed bone areas in defects for PGA/HAp disk were significantly higher at two and three months after surgery than in controls that underwent sham operations. The results suggest that the biological properties of the PGA-based trial prototype were increased with the addition of HAp. An orthodontic anchor screw constructed of PGA may be useful for orthodontists.

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Fracture of the mandibular condyle accounts for 20-30 % of mandibular fracture cases overall. We will hereby report on four cases of fracture of the mandibular condyle for which good outcomes were achieved by means of fixation and aggressive mouth-opening exercises using a bite plate as a type of conservative treatment. Patients between the ages of 6 and 53 years with the mean age of 37.25 years were investigated. The male to female ratio was 3:1. Of the four patients with fracture of the mandibular condyle, three exhibited midline fracture of the mandible. Bite plates were fabricated and intermaxillary fixation was conducted for 1-3 weeks with these bite plates for patients who presented at hospital from 1-10 days after injury and were refused surgery. After completion of intermaxillary fixation, aggressive mouth-opening exercises were implemented. Once sufficient mouth opening was possible, the healing progress was confirmed on computed tomography (CT) images. Treatment methods for fracture of the mandibular condyle include invasive and non-invasive ones. Favorable treatment outcomes were achieved with intermaxillary fixation using a bite plate and mouth-opening exercises in this study. Therefore, we conducted a preliminary study on the efficacy of this treatment and will hereby report on the results.

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The purpose of this study is to evaluate an ability of a moldable autogenous tooth bone graft material (M-AutoBT), which is made of demineralized dentin matrix (DDM) and hydroxypropylmethyl cellulose (HPMC) to repair sinus-related defects in the implant dentistry. Sinus-related alveolar defects were classified into three types depending on the remnant of socket wall as follows; Class I: Only alveolar bone repair is required even if sinus cavity is involved (remained socket wall > 5mm). Class II: Both alveolar bone and sinus repair are required (3mm < remained socket wall < 5mm). Class III: Only sinus repair is required without any alveolar bone (remained socket wall < 3mm). Sinus cavity should always be involved during the implant placement regardless of defect types. The histological examination of three case reports, which represented class I, II and III defect respectively, showed osteoconductive and osteoinductive functions of M-AutoBT that is similar to the effect of the conventional AutoBT. Therefore, HPMC might be the suitable base material for AutoBT.

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The mechanism in the formation of periodontal polyp has been established in several histological studies but details on cell differentiation and/or proliferation have not been elucidated. In the present study, we established a convenient and possible experimental system using ddY mice. Briefly, pentobarbital sodium (Somnopentyl) was injected into the abdominal cavity of the mouse followed by access cavity preparation on maxillary first molar using low speed ½ round bur (Merufa Inc), exposing the pulp and then allowed to perforate the floor of the pulp chamber. Observation was done over time until 6 months using micro CT (m_CT) image photography. Results with transmission image using m_CT showed the expansion in the width of the periodontal ligament in the furcation area. The lesion was excised as one mass and examined histopathologically. The granulation tissue was covered with stratified squamous epithelium. The present experimental technique has been confirmed to be effective in analyzing the formation of periodontal polyp induced by mechanical perforation.

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CD81 belongs to a family of cell-surface proteins (tetraspanins) that have four transmembrane domains and two outer-membrane loops. CD81 has been shown to be up-regulated in rheumatoid arthritis (RA) synoviocytes and is involved in the progression of RA through the promotion of synoviolin expression. Recently, we showed that small interfering RNA targeting CD81 (CD81 siRNA) ameliorates paw swelling in collagen-induced arthritic (CIA) rats. CD81 siRNA also decreases the expression of TNF-α in SW982 cells. Previously, we established hybridoma cell lines producing monoclonal antibodies (MAbs) against CD81, which decrease the proliferation of rat C6 glioma cells. Here, we established a sandwich enzyme-linked immunosorbent assay (ELISA) system for the quantitation of CD81 using these MAbs.

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