Cranial bone regeneration after cranioplasty using cryopreserved autogenous bone by a programmed freezer with a magnetic field in rats.

BACKGROUND: The purpose of this study was to develop a bone tissue bank using a programmed freezer with a magnetic field. Parietal bones were removed from rats and used for organ culture examination (non-cryopreserved, cryopreserved with a magnetic field (CAS) and cryopreserved without a magnetic field group). Next, other parietal bones were used for histological examination. The cryopreserved bones by a CAS freezer and dried bones were transplanted respectively. Control bones were replanted without cryopreservation. Animals were sacrificed at 4, 8, 12 and 24 weeks after surgery. After organ culture, the isolated osteoblasts from parietal bones which were cryopreserved by a CAS freezer can survive and proliferate as much as non-cryopreserved group. Histological examinations showed new bone formation in control and CAS group. These results suggest that bone tissue cryopreservation by CAS freezer can be successfully used for bone grafting which may be a novel option for regeneration medicine.

Gummy smile and facial profile correction using miniscrew anchorage.

This case report describes the treatment of a case involving a skeletal Class II facial profile with a gummy smile. While treating a facial profile and a gummy smile, the outcome may not always be successful with orthodontic therapy alone. For this reason, surgical therapy is often chosen to gain an esthetic facial profile and a good smile. However, sometimes the patients reject surgical treatment and an alternative method must be considered. Skeletal anchorage systems such as miniscrews are now frequently used for correcting severe malocclusion that should be treated by surgical therapy. In this case report, we treated a skeletal Class II malocclusion with a convex profile and a gummy smile using miniscrews, which were placed in the upper posterior and anterior areas. The active treatment period was 3.5 years, and the patient's teeth continued to be stable after a retention period of 36 months.

In-vitro and in-vivo study of periodontal ligament cryopreserved with a magnetic field.

INTRODUCTION: The purpose of this study was to examine the effect of a new cryopreservation method with a magnetic field on periodontal regeneration in vitro and in vivo. METHODS: Human periodontal ligament cells were frozen in 10% dimethyl sulfoxide by using a programmed freezer with a magnetic field. Cells were cryopreserved for 3 days at -150°C. Immediately after thawing, collagen type I and alkaline phosphatase gene expression were determined by real-time polymerase chain reaction. Incisors were extracted from 15-week-old Wistar rats and cryopreserved or dried for 3 days. Then the incisors were replanted into the same sockets. Ninety days after transplantation, they were observed under light microscopy. RESULTS: There was no difference in the messenger RNA expression of collagen type I between the cryopreserved and the control groups. The expression of alkaline phosphatase messenger RNA in the cryopreserved group was slightly decreased compared with the control group. There was no progressive root resorption in the teeth that were replanted immediately (control group) or cryopreserved. However, there was widespread root resorption and ankylosis in the dried teeth. CONCLUSIONS: These results show that a magnetic field programmed freezer can be successfully used for cryopreservation of teeth.

Treatment of a case of skeletal class II malocclusion with temporomandibular joint disorder using miniscrew anchorage.

At the present time, there are no reports in the literature on the treatment of temporomandibular joint disorder (TMD) by intrusion of molars using mini-screws. This case report describes the treatment for a female patient, aged 19 years seven months, with a TMD and an excessive lower anterior facial height. Overjet and overbite were +5.0 mm and +0.5 mm, respectively. The patient had a history of orthodontic treatment in which her first premolars were all extracted. During the first orthodontic treatment, a clockwise mandibular rotation was observed as a result of the increase of posterior dentoalveolar height. She had temporomandibular joint (TMJ) pain during mouth opening and complained of difficulty in eating due to masticatory dysfunction. The pretreatment Schuller views of both TMJ showed a posterior condyle position. In order to correct the overjet, molar relationship and the mandibular condyle position, a miniscrew was inserted into the palatal region of the upper first molar to intrude the upper posterior teeth. As the upper molars were intruded, the overjet was decreased, and a class I molar relationship was achieved by a counterclockwise mandibular rotation. After one year of treatment, an acceptable occlusion was achieved, and the condyle moved into centric position in the glenoid fossa. The patient's teeth continued to be stable, and she had no pain in TMJ after a retention period of three years. The result of this treatment showed that molar intrusion using miniscrew anchorage is effective for treatment of a TMD patient with a posterior condyle position.

A newly developed snack effective for enhancing bone volume.

BACKGROUND: The incidence of primary osteoporosis is higher in Japan than in USA and European countries. Recently, the importance of preventive medicine has been gradually recognized in the field of orthopaedic surgery with a concept that peak bone mass should be increased in childhood as much as possible for the prevention of osteoporosis. Under such background, we have developed a new bean snack with an aim to improve bone volume loss. In this study, we examined the effects of a newly developed snack on bone volume and density in osteoporosis model mice. METHODS: Orchiectomy (ORX) and ovariectomy (OVX) were performed for C57BL/6J mice of twelve-week-old (Jackson Laboratory, Bar Harbar, ME, USA) were used in this experiment. We prepared and given three types of powder diet e.g.: normal calcium diet (NCD, Ca: 0.9%, Clea Japan Co., Tokyo, Japan), low calcium diet (LCD, Ca: 0.63%, Clea Japan Co.,) and special diet (SCD, Ca: 0.9%). Eighteen weeks after surgery, all the animals were sacrified and prepared for histomorphometric analysis to quantify bone density and bone mineral content. RESULTS: As a result of histomorphometric examination, SCD was revealed to enhance bone volume irrespective of age and sex. The bone density was increased significantly in osteoporosis model mice fed the newly developmental snack as compared with the control mice. The bone mineral content was also enhanced significantly. These phenomena were revealed in both sexes. CONCLUSION: It is shown that the newly developed bean snack is highly effective for the improvement of bone volume loss irrespective of sex. We demonstrated that newly developmental snack supplements may be a useful preventive measure for Japanese whose bone mineral density values are less than the ideal condition.

Fms-like tyrosine kinase (Flt)-4 signaling participates in osteoclast differentiation in osteopetrotic (op/op) mice.

Vascular endothelial growth factor (VEGF) induces osteoclast differentiation as well as neovascularization by binding to the fms-like tyrosine kinase (Flt)-1 and fetal liver kinase (Flk)-1 receptors. The Flt-4 receptor also plays an important role in angiogenesis and lymphangiogenesis. The purpose of this study was to investigate the functions of Flt-4 in the signaling pathway of osteoclast differentiation. We examined the expression of Flt-4 on osteoclast precursor cells (OCPs), and the ability of recombinant human (rh) VEGF-D, one of the ligands of Flt-4, to stimulate the phosphorylation of extracellular-regulated kinase1/2 (ERK1/2) and to activate the nuclear factor-kappa B (NF-kappaB) pathway in OCPs. The number of osteoclasts induced by injection of rhVEGF-D in osteopetrotic (op/op) mice was also evaluated in the absence or presence of neutralizing antibodies to Flt-4. Flt-4 expression was detected on OCPs at both gene and protein levels and stimulation of Flt-4 by rhVEGF-D might induce activation of mitogen-activated protein kinase (MAPK) and NF-kappaB pathways for induction of osteoclast differentiation. Moreover, the number of osteoclasts in op/op mice increased after injection of rhVEGF-D, but was significantly reduced by the injection of Flt-4 neutralizing antibodies. We have therefore shown that Flt-4 expressed on OCPs, might activate MAPK and NF-kappaB pathways and played an important role in osteoclast differentiation.

VEGF and M-CSF levels in periodontal tissue during tooth movement.

It has been reported that both vascular endothelial growth factor (VEGF) and macrophage colonystimulating factor (M-CSF) can induce osteoclast recruitment. Thus, VEGF and M-CSF are considered to be closely involved in the bone remodeling process. The purpose of this study was to evaluate changes in VEGF and M-CSF expression during orthodontic treatment. The expression of VEGF and M-CSF mRNA in osteoblasts and fibroblasts was detected by in situ hybridization during experimental tooth movement in mice. Furthermore, the canine retraction side and the control side of orthodontic patients were compared, revealing a statistically significant increase in both VEGF and M-CSF concentrations in gingival crevicular fluid. These results suggest that orthodontic tooth movement causes an increase in VEGF and M-CSF levels. These factors may induce bone remodeling via osteoclastic bone resorption.