To clarify the effects of low-intensity pulsed ultrasound (LIPUS) irradiation on the myotubes differentiation of the myoblast cell line, C2C12, derived from mouse skeletal muscle, gene expression levels after differentiation induction were quantified by real-time PCR. First of all, no calcium deposit was detected by von Kossa staining in LIPUS-irradiated C2C12 cells, demon strating no induction of bone differentiation. Subsequently, the expression levels of the following genes were measured : ERK5 (signal-promoting factor for cell fusion), Klf2 (transcriptional activator), Cdh15 (cell adhesion factor), MyoD and Myogenin (transcriptional activators of muscle-specific genes), and MCK (Muscle Creatine Kinase).
As a result, LIPUS irradiation enhanced the relative gene expression levels of the ERK5, Klf2, and Cdh15 genes at 23 hours after the induction of differentiation, suggesting the promotion of cell fusion. The relative gene expression levels of the Cdh15 gene were enhanced again at 7 days after the induction of differentiation, with elongated cells after fusion. Moreover, the expression levels of the MyoD and Myogenin genes were also enhanced, with increased level of expression of a final myo tubes differentiation marker, MCK, from the early stage of differentiation. It is suggested that myotubes differentiation was completed earlier.
Laminin 332 (LN332) is an extracellular matrix that enhances the adhesion and migration of epithelial cells. The specific binding of LN332 on titanium (Ti) surfaces may serve to enhance the biological sealing at the epithelium-implant interface. Accordingly, it is important to analyze the response and application of LN332 on titanium implants. Superhydrophilic surface modification is reported to enhance the adsorption of proteins to titanium. This study aimed to evaluate the binding behavior of LN332 on surface-modified Ti with superhydrophilicity. In addition, the mechanism by which adsorption of LN332 is enhanced was examined by surface analyses.
Atmospheric-pressure plasma treatment (Ti-Plasma) and ultraviolet treatment (Ti-UV) as superhydrophilic treatments were performed on a titanium sensor that was designed for quartz crystal microbalance (QCM-D) apparatus. Untreated gold (Au-Air) or titanium sensor (Ti-Air) was used as a control. Adsorption properties of LN332 were assessed using a QCM-D method. In addition, surface characteristics were examined with X-ray photoelectron spectroscopy (XPS) and SEM observation using LN332-adsorbed specimens.
The amount of LN332 adsorption was increased on Ti-Air compared to Au-Air. In addition, the specific binding of LN332 was increased on the superhydrophilic treatment groups (Ti-Plasma and Ti-UV) compared with Ti-Air. Surface analyses of LN332-adsorbed surfaces revealed that carbon (C) and nitrogen (N) contents as well as carbonyl group, carboxyl group and peptide-related group were increased on the Ti-Plasma and Ti-UV specimens. Accordingly, peptide bonds seemed to play an important role on the specific binding of LN332 to surface-modified titanium with superhydrophilicity.
These results suggested that the superhydrophilic modifications may promote the adhesion of LN332 to titanium.
Background : Platform-switched (PS) implants are beneficial for preserving the peri-implant bones, but their effects on the soft tissue remain unclear.
Purpose : The purpose of this study was to compare the effects of implant platform shape on the expression of collagens and adhesion factors in the soft tissue surrounding implants.
Materials and Methods : Ten-week-old rats were randomized into three groups : sham group, non-PS (NPS) group, and PS group. At 2 and 4 weeks after the implantation, the peri-implant soft tissues were harvested and the expression of collagen and cell adhesion molecules was analyzed using real-time PCR. Collagen expression in the decalcified specimens was analyzed immunohistochemically.
Results : We demonstrated that type Ⅻ collagen expression significantly increased in the PS group compared with that in the sham and NPS groups. However, no differences in type I collagen expression were observed between the groups. In the PS group, the expression of integrin α1β1 and connexin 43 was significantly increased compared with that in other groups. Circular collagen fibers were observed in the platform section of the peri-implant soft tissue in the PS group.
Conclusions : Our findings indicate that the PS implant stabilizes the peri-implant soft tissue by organizing closely bound collagen fibers through type Ⅻ collagen expression modulation.
Objective : This study examined the meaning of screening of bone density on panoramic radiography by investigating the correlation between the depiction of the mandibular canal on a panoramic radiograph and bone density, as evaluated on a computed tomography (CT) image of the mandibular molar area.
Materials and Methods : This retrospective cohort study comprised 99 patients aged 50 years or older who underwent panoramic radiography and CT imaging. A total of 147 sites were included, comprising mandibular molar areas ; 70 sites were partially or fully edentulous with respect to the mandibular molars, and 77 sites showed no defect in the mandibular molars. Depiction of the mandibular canal on panoramic radiography was classified into three types : typeⅠ, mandibular canal visible in superior and inferior walls ; typeⅡ, mandibular canal visible in inferior and invisible in superior walls ; and typeⅢ, mandibular canal invisible in superior and inferior walls. In addition, the correlation between the mandibular canal depiction on panoramic radiography and bone density evaluated by CT images of the mandibular molar area was investigated.
Results : In the case of a panoramic radiograph showing a decrease in depiction of the mandibular canal, cortical bone and cortical bone width on the buccal side and lower border side of CT decreased. In addition, although there was no difference in the CT value within the mandibular canal due to depiction of the mandibular canal, a significant difference was found in the CT value of the outer circumference of the mandibular canal.
Conclusion : The ratio of the width of the cortical bone, as well as the CT value around the mandibular canal, both decreased when mandibular canal depiction on panoramic radiography was unclear. These results indicate that the depiction of the mandibular canal on panoramic radiography enables screening of bone density for dental implant therapy.
At the Japanese Society of Oral Implantology, a specialist medical system is in force. However, even the same specialist sees various ideas and procedures in the actual clinical practice of oral implantation.
To ensure the safety of oral implants, the trend of the actual clinical practice of specialists should be clarified and linked to education. This time, using a 25-item oral implant-related questionnaire, we surveyed 102 specialists who were members of the Clinical Implant Society of Japan, in order to analyze oral implants, implantation techniques, prosthodontics, maintenance of oral implants, implantation time, implant material, and so on in clinical practice in Japan. However, responses were inconsistent; some clearly described the protocols used, whereas others did not.
Thus, it is considered necessary to further clarify the protocol, enhance education and training, and improve the knowledge and skills of specialists to ensure the safety of oral implants.