Search

In this study, for improving the bioactivity of titanium used as an implant material, alkali and heat treatments were carried out after formation of the nanotubes via anodization. Nanotubes with uniform length, diameter, and thickness were formed by anodization. The alkali and heat-treated TiO2 nanotubes were covered with the complex network structure, and the Na compound was generated on the surface of the specimens. In addition, after 5 and 10 days of immersion in the SBF, the crystallized OCP and HAp phase was significantly increased on the surface of the alkali-treated TiO2 nanotubes (PNA) and alkali and heat-treated TiO2 nanotubes (PNAH) groups. Cell proliferation was decreased due to the formation of amorphous sodium titanate (Na2TiO3) layer on the surface of the PNA group. However, anatase and crystalline sodium titanate were formed on the surface of the PNAH group after heat treatment at 550 °C, and cell proliferation was improved. Thus, PNA group had higher HAp forming ability in the simulated body fluid. Additional heat treatment affected on enhancement of the bioactivity and the attachment of osteoblasts for PNA group.

The aim of this study was to clarify the spatial relationship between the facial artery and the insertion of the zygomaticus major muscle in the perioral region. In 30 of 70 dissections (42.9%), the facial artery passed through the separate muscle bands of the zygomaticus major muscle. The mean diameter of the facial artery passing through the zygomaticus major muscle in this region was 1.74 mm (range 0.82-2.86 mm). The relationship between the facial artery and the insertion of the zygomaticus major muscle in the perioral region described in this study is expected to provide critical information for surgical planning and procedures around the perioral region.

Until now there has been no definitive anatomical study describing the area where the parotid duct enters the buccinator muscle. In this study, we performed anatomical and histological examinations to investigate the relationship between the parotid duct and the buccinator muscle. Thirty specimens (including the buccinator and the terminal portion of the parotid duct) were obtained from embalmed Korean cadavers. Dissection was performed on 22 of these specimens, and the remaining eight specimens were prepared for histological examination and stained with haematoxylin–eosin or Gomori trichrome. In all specimens, small, distinct muscle fibres originating from the buccinator muscle extended to and inserted into the terminal portion of the parotid duct. The topography of these fibres varied, and we classified them into three categories according to where they originated. Type I buccinator muscle fibres, which inserted into the terminal portion of the parotid duct, originated simultaneously from the anterior and posterior aspects of the duct (ten cases, 45.5%). Type II fibres originated from the anterior aspect of the duct and inserted into the anterior side of the duct (seven cases, 31.8%). Type III fibres originated from the posterior aspect of the parotid duct and ran anteriorly toward the duct (five cases, 22.7%). These results were confirmed in the histological examination of all eight specimens. Based on these findings, we have proposed a tentative description of the physiological role of the buccinator muscle fibres in salivary secretion and in the formation of the sialoliths.

To examine the changes of the mechanical properties of 7 different light-cured composite resins after thermal cycling and the correlations between these properties.Seven different light-cured composite resins, including 2 microfilled composites (A110:AH and ESTELITE :ET), 3 microhybrid composites (AELITE:AT, Z250:ZS, and CharmFil plus:CP), and 2 nanohybrid composites (Z350:ZH and Grandio:GD), were prepared into test specimens with a diameter of 12 mm and a thickness of 1.0 mm. The specimens were stored in distilled water at 37 degrees celsius; for 24 h prior to 1 000 thermal cycles of 5 degrees celsius; for 15 s and 55 degrees celsius; for 15 s. The biaxial flexural strength (δ(f)) was tested using the ball-on-three-ball method at a crosshead speed of 0.5 mm/min (ISO4049). The fracture surface was observed under scanning electron microscope (SEM), and the remaining specimens underwent Knoop hardness test with a 50-g loading for 10 s.The highest and lowest Weibull modulus was observed in AH (18.752) and AT (5.290) group, respectively. The highest and lowest biaxial flexural strength was observed in ZS (158.2 MPa) and ET (54.0 MPa) groups, respectively. The δ(f) of the tested materials decreased in the order of microhybrid composite, nanohybrid composite, and microfiller composite, and the δ(f) showed no significant difference between the composites with a similar filler (P0.05). The fracture number was positively correlated to the strength of the material. The Knoop hardness numbers (H) was the highest in GD group (110.81∓14.77 kg/mm(2)) and the lowest in AH group (42.81∓1.91 kg/mm(2)). SEM showed that the interface region of the matrix and the filler was vulnerable to crack formation.The nanohybrid composite resins better suit clinical applications than microhybrid composites. The applicability of Knoop hardness test in hardness measurement of the composite resins needs to be further demonstrated.

In order to bind or fix bioactive materials directly to the surface of a Ti implant, the prior binding process of functional groups (FGs, -COOH and -OH) to the implant surface is necessary. Conventional binding processes are so high-cost and complex, so it is essential to find a simple and effective procedure for Ti-FG binding.Various electrolyte compositions and electrochemical processing were adopted in this study to develop a relatively simple and effective Ti-FG binding process. The ability of Ti-FG binding and calcium (Ca)/phosphorous (P) absorption and corrosion resistance were evaluated according to various titanium surface treatment in electrolyte involving -COOH and -OH ion by using X ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FE-SEM) and potentiodynamic scan method respectively.In cases of -COOH, the anodic oxidation process (AN) showed an effective binding ability between -COOH and Ti surface. On the other hand, in cases of -OH, there were no significant differences in the result between the conditions used. In regard to the absorption of Ca and P on Ti surface, there was a minimal amount of Ca absorbed but no P was absorbed. The anodic oxidation series showed homogenous corrosion, whereas the electrolyte immersion (EL) series showed unstable corrosion. Although EL-OH showed a novel corrosion potential, the EL-COOH series showed good corrosion resistance over the anodic potential range.The ability of binding between FG and the Ti surface and Ca/P absorption were strongly associated with the surface potential (ζ potential), which was dependent on the pH of the electrolyte. Accordingly, in order to achieve the effective absorption of various FGs on the Ti surface, it is needed to develop the combination process in addition to the electric affinity, relation with the ζ potential.

The dramatic changes in facial expression are most remarkable in the perioral region. Among the perioral musculatures, the zygomaticus major (ZMj) muscle plays an important role in the facial expression. The aim of this study was to determine the anatomic patterns of the bifid ZMj through a topographic examination at the perioral region. Through 70 dissections of the hemifaces, the insertion area of the ZMj was observed in 70 embalmed cadavers. The bifid ZMj was observed in 28 cases (40%). In most cases of the bifid ZMj, the superior muscle fibers were larger and wider than the inferior fibers. Bilateral bifid ZMj was found in 71.4% of the bifid ZMj specimens. The arrangement and insertion patterns of the ZMj in this study are expected to provide critical information for the surgical planning and procedure for facial reanimation surgery.

The aim of this study was to investigate the prevalence and configuration of the C-shaped canal using serial axial computed tomography images of the mandibular second molars that had not been restored severely or treated endodontically, and to compare the thickness of the remaining tooth structure from the center of the canal to the outer surface of the deepest groove area in C-shaped mandibular second molar to that of "danger zone of perforation" in normal mandibular second molar. This distance was measured at the cervical, middle, and apical third level each. From 220 teeth, C-shaped canals were found in 98 teeth (44.5%). Almost all the grooves were directed lingual (99%). The continuous C-shaped canal was the most frequently found (49%) and the separated canal was the least (17.4%). The thinnest remaining tooth structure in the groove area of the C-shaped mandibular second molar was not different from that of the danger zone of normal mandibular second molar at the three levels (p > 0.05).

Background: Pain remains the chief complaint that brings patients to physician's office, despite recent insights into underlying mechanism and the identification of potential new therapeutic targets. In recent years, however, with the development of molecular biology cell transplantation gives us a new chance for treating intractable chronic pain. The major purpose of the present study was to determine if the chromaffin cells that were encapsulated with 1.3% (w/v) sodium alginate-poly-l-lysine-alginate (APA) had robust analgesic effects in the spinal atlanto-occipital subarachnoid space even without nicotine stimulation. Methods: In order to determine whether microencapsulated bovine adrenal medullary chromaffin cells transplanted in the spinal cord can produce analgesic effects, we microencapsulated adrenal medullary chromaffin cells with APA and implanted them into the subarachnoid space of rats' (n = 10) spinal cord, and investigated the hot sensitivity of rats' hind-paw by a light-beam test. Results: It was found that compared with the control group, hot response latency of the group which received adrenal medullary chromaffin cells increased from the 12th day and the analgesic efficacy was maintained for at least 75 days. Conclusions: Microencapsulated bovine adrenal medullary chromaffin cells transplanted in the rats' spinal cord may provide a permanent and locally available source of neuropeptides for the relief of intractable pain. Furthermore, these kinds of analgesic effect were produced without any stimulation such as nicotine.