Sun-Kyoung Yu

Autogenous teeth used for bone grafting: a comparison with traditional grafting materials.

OBJECTIVES This study evaluated the surface structures and physicochemical characteristics of a novel autogenous tooth bone graft material currently in clinical use. STUDY DESIGN The materials surface structure was compared with a variety of other bone graft materials via scanning electron microscope (SEM). The crystalline structure of the autogenous tooth bone graft material from the crown (AutoBT crown) and root (AutoBT root), xenograft (BioOss), alloplastic material (MBCP), allograft (ICB), and autogenous mandibular cortical bone were compared using x-ray diffraction (XRD) analysis. The solubility of each material was measured with the Ca/P dissolution test. RESULTS The results of the SEM analysis showed that the pattern associated with AutoBT was similar to that from autogenous cortical bones. In the XRD analysis, AutoBT root and allograft showed a low crystalline structure similar to that of autogenous cortical bones. In the CaP dissolution test, the amount of calcium and phosphorus dissolution in AutoBT was significant from the beginning, while displaying a pattern similar to that of autogenous cortical bones. CONCLUSIONS In conclusion, autogenous tooth bone graft materials can be considered to have physicochemical characteristics similar to those of autogenous bones.

MicroRNA-205 Directly Regulates the Tumor Suppressor, Interleukin-24, in Human KB Oral Cancer Cells

MicroRNA (miRNA) is a form of small noncoding RNA that regulates the expression of genes either by inhibiting mRNA translation or by inducing its degradation. Small microRNA play important roles in regulating a large number of cellular processes, including development, proliferation and apoptosis. This study examined the biological functions of miR-205 as a tumor suppressor in KB oral cancer cells. The results showed that miR-205 expression was significantly lower in KB oral cancer cells than in human normal oral keratinocytes. Furthermore, the miR-205 over-expressed in KB oral cancer cells increased the cell cytotoxicity and induced apoptosis through the activation of caspase-3/-7. The transfection of miR-205 into KB oral cancer cells strongly induced IL-24, a well known cytokine that acts as a tumor suppressor in a range of tumor tissues. In addition, miR-205 targeted the IL-24 promoter directly to induce gene expression. Overall, miR-205 has significant therapeutic potential to turn on silenced tumor suppressor genes by targeting them with miRNA.

Histological assessment of the palatal mucosa and greater palatine artery with reference to subepithelial connective tissue grafting.

This study aimed to measure the thickness of the epithelium and lamina propria of the palatal mucosa and to elucidate the location of the greater palatine artery to provide the anatomical basis for subepithelial connective tissue grafting. Thirty-two maxillary specimens, taken from the canine distal area to the first molar distal area, were embedded in paraffin and stained with hematoxylin-eosin. The thickness of the epithelium and lamina propria of the palatal mucosa was measured at three positions on these specimens, starting from 3 mm below the alveolar crest and in 3-mm intervals. The location of the greater palatine artery was evaluated by using image-processing software. The mean epithelial thickness decreased significantly in the posterior teeth; it was 0.41, 0.36, 0.32, and 0.30 mm in the canine, first premolar, second premolar, and first molar distal areas, respectively. The lamina propria was significantly thicker in the canine distal; it was 1.36, 1.08, 1.09, and 1.05 mm, respectively. The mean length from the alveolar crest to the greater palatine artery increased toward the posterior molar; it was 7.76, 9.21, 10.93, and 11.28 mm, respectively. The mean depth from the surface of the palatal mucosa to the greater palatine artery decreased from the canine distal to the first premolar distal but increased again toward the posterior molar; it was 3.97, 3.09, 3.58, and 5.50 mm, respectively. Detailed histological assessments of the lamina propria of the palatal mucosa and the greater palatine artery are expected to provide useful anatomical guidelines for subepithelial connective tissue grafting.

Induction of apoptosis by diphenyldifluoroketone in osteogenic sarcoma cells is associated with activation of caspases

The aim of the present study was to investigate and compare the effects of diferuloylmethane (curcumin) and diphenyldifluoroketone (EF-24) on cell growth and apoptosis induction in human osteogenic sarcoma cells. This was examined by MTT assay, nuclear DAPI staining, caspase-activation assay, flow cytometry analysis and immunoblotting in Saos2 human osteogenic sarcoma cells. Curcumin and EF-24 inhibited the growth of Saos2 cells in a dose-dependent manner. The apparent potency of EF-24 was more than 3-fold higher that of curcumin. Treatment with curcumin or EF-24 resulted in nuclear condensation and fragmentation in the cells. The caspase-3/-7 activities were detected in living cells treated with curcumin or EF-24. Flow cytometry showed that the rate of apoptosis was increased by curcumin and EF-24 compared to the control. Curcumin and EF-24 promoted the proteolytic cleavages of procaspase-3/-7/-8/-9 with increases in the amount of cleaved caspase-3/-7/-8/-9. The curcumin- or EF-24-induced apoptosis in the Saos2 cells was mediated by the expression of Fas and activation of caspase-8, caspase-3 and poly(ADP-ribose) polymerase. Immunoblotting revealed the Bid and Bcl-2 proteins to be downregulated, and truncated-Bid, Bax and p53 proteins to be upregulated by curcumin and EF-24. Curcumin and EF-24 increased the Bax/Bcl-2 ratio significantly. These results suggest that the curcumin and EF-24 inhibit cell proliferation and induce apoptotic cell death in Saos2 human osteogenic sarcoma cells via both the mitochondria-mediated intrinsic pathway and the death receptor-mediated extrinsic pathway, and may have potential properties for anti-osteosarcoma drug discovery.

Histomorphologic approach for the modiolus with reference to reconstructive and aesthetic surgery.

AbstractThe modiolus is strongly associated with facial expression, beauty, and aging, and so it is often viewed as the main facial landmark, both functionally and aesthetically. This study examined the modiolus and the surrounding structures histomorphologically with the aim of providing useful information for reconstructive and aesthetic surgery. Nineteen embalmed cadavers (38 hemifaces; 8 males and 11 females; mean age at death, 66.9 years) were examined in this study. For macroscopic observations, the modiolus and facial artery in the perioral region of 28 hemifaces were revealed by meticulous dissection. The modiolus and its surrounding structures were then prepared from 12 hemifaces for routine histology and stained with hematoxylin-eosin and Masson trichrome. A tendinous tissue nodule in the modiolus was found in 21.4% of cases (ie, 6 hemifaces). The facial artery passed approximately 1 mm lateral to the lateral border of the modiolus. In the central region of modiolus, which was an area of convergence of muscle fibers, the tendinous structure appeared as dense irregular collagenous connective tissue. Particularly in the middle layer between the skin and the oral mucosa, it appeared as a dense, compact, and prominent shape horizontally. The finding of the existence of a tendinous structure in the central region of the modiolus, which could act as an anchor for the converging facial muscles, is expected to provide critical information in the field of facial plastic surgery.

Anatomical configuration of the inferior alveolar neurovascular bundle: a histomorphometric analysis

PurposeThe inferior alveolar neurovascular bundle (NVB) is important in implant placement and many other surgeries in dentistry because it is a major supplier of sensation and blood to the mandible via the mandibular canal. The purposes of the present study were to determine the areas and diameters of the NVB, the inferior alveolar nerve (IAN), and the inferior alveolar artery (IAA), and to verify the buccolingual location of the mandibular canal.MethodsThe anatomical configuration of the NVB was examined by histomorphometrically analyzing 20 embalmed dentulous hemimandibles. The areas and maximum horizontal and vertical diameters of the NVB, IAN, and IAA were measured according to tooth region. The distances from the internal border of the mandibular canal to the outer surface of the buccal and lingual cortical plates were also measured.ResultsThe areas of the vertically oval-shaped NVB and IAN appeared to be constant between the molar and premolar regions, which contain the mental branch, and decreased sharply in the lateral incisor after branching off of the mental branch via the mental canal. The mandibular canal was located close to the lingual cortical plate in the posterior tooth region before passing through the mental canal, immediately after which it was situated quite close to the buccal cortical plate, and then closer to the middle toward the anterior tooth region.ConclusionsThe findings of this study provide useful anatomical information that should help to minimize the risk of injury to the NVB during surgical procedures in the mandibular region.

Cortical and cancellous bone thickness on the anterior region of alveolar bone in Korean: a study of dentate human cadavers

PURPOSE The cortical bone thickness on the anterior region is important for achieving implant stability. The purpose of this study was to examine the thickness of the cortical and cancellous bones on the anterior region of the maxilla and mandible. MATERIALS AND METHODS Twenty-five cadaver heads were used (16 male and 9 female; mean death age, 56.7 years). After the long axis of alveolar process was set up, it was measured in 5 levels starting from 2 mm below the cementoenamel junction (L1) at intervals of 3 mm. All data was analysed statistically by one-way ANOVA at the .05 significance level. RESULTS The cortical bone thickness according to measurement levels in both the labial and lingual sides increased from L1 to L5, and the lingual side below L3 was significantly thicker than the labial side on the maxilla and mandible. In particular, the labial cortical bone thickness in the maxilla was the thinnest compared to the other regions. The cancellous bone thickness according to measurement levels increased from L1 to L5 on the maxilla, and on the mandible it was the thinnest at the middle level of the root. CONCLUSION For implant placement on the anterior region, a careful evaluation and full knowledge on the thickness of the cortical and cancellous bone are necessary, therefore, these results may provide an anatomic guideline to clinicians.

Anticancer activities of diphenyl difluoroketone, a novel curcumin analog, on KB human oral cancer cells

Effects of diphenyl difluoroketone (EF-24) and curcumin on cell growth and apoptosis induction in KB human oral cancer cells were examined. EF-24 and curcumin inhibited the growth of KB cells in a dose-dependent manner, and the potency of EF-24 was 30 times greater than that of curcumin. Treatment with EF-24 or curcumin resulted in nuclear condensation and fragmentation. EF-24 and curcumin promoted the proteolytic cleavage of procaspases-3, -7, and -9. Activities of caspases-3 and -7 were detected in living KB cells treated with EF-24 or curcumin. These results suggest that EF-24 and curcumin inhibit cell proliferation and induce apoptosis in KB human oral cancer cells, and have potential properties for development of anti oral cancer drug.

Resveratrol Induces Apoptosis of KB Human Oral Cancer Cells

Resveratrol (trans-3,4′s,5,-trihydroxystilbene), a phytoalexin present in grape skin and red wine, suppresses many types of cancers by regulating cell proliferation and apoptosis through a variety of mechanisms. However, the effects of resveratrol on oral cancer are not completely understood. Thus, effects of resveratrol on cell growth and apoptosis induction were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, DNA fragmentation, immunoblotting, and determination of caspase activation in KB human oral cancer cells. Treatment with resveratrol induced inhibition of cell growth depending on the resveratrol treatment time and concentration in KB cells. Treatment with resveratrol induced DNA ladder formation in KB cells and promoted proteolytic cleavage of procaspase-3 and procaspase-7 with increases in the amount of cleaved caspases-3 and -7. Proteolytic processing of caspase-9 in KB cells was increased by resveratrol treatment. Activation of caspase-3/-7 was detected in living KB cells by fluorescence microscopy. These results suggest that the resveratrol can suppress cell growth and induce cell apoptosis in KB human oral cancer cells, and may have potential as an anti-cancer drug.

Histologic features and fascicular arrangement of the inferior alveolar nerve

OBJECTIVES Knowledge of the various possible morphologies and courses of the inferior alveolar nerve and artery is important for successful and safe surgical procedures in the mandibular region. The purpose of this study was to verify the histologic features and fascicular arrangement of the inferior alveolar nerve and artery relative to tooth region. MATERIALS AND METHODS Twenty embalmed dentulous hemimandibles were examined (eight males and two females; mean age, 58.2 years). The hemimandibles were prepared for routine histology and stained with hematoxylin-eosin and Massons trichrome. The histologic features, fascicular arrangement, courses, and areas of the inferior alveolar nerve and artery were investigated with the aid of a light microscope. RESULTS The inferior alveolar neurovascular bundle comprised the inferior alveolar nerve, which appeared as a large trunk comprising two major nerves (the mental and dental nerves), and the inferior alveolar artery, which occupied a relatively small portion of the bundle. The mental nerve was located inferolingually in the third molar region and turned to the buccal side in the first molar region, separating from the dental nerve before reaching the mental foramen. The mandibular incisive canal with a bony wall was not found in the lateral incisor region; instead, small dental nerve fascicles and arteries presented consistently in the intertrabecular spaces. The inferior alveolar artery traveled above the inferior alveolar nerve over the entire mandibular canal. CONCLUSIONS These results provide data that are relevant to treatment planning for operative procedures such as implant placement, endodontic treatment, and osteotomy in the mandibular region.