Nicotinamide phosphoribosyltransferase regulates the cell differentiation and mineralization in cultured odontoblasts

The aim of the present study was to investigate the physiological role of nicotinamide phosphoribosyltransferase (NAMPT) associated with odontogenic differentiation during tooth development in mice. Mouse dental papilla cell-23 (MDPC-23) cells cultured in differentiation media were stimulated with the specific NAMPT inhibitor, FK866, and Visfatin (NAMPT) for up to 10 days. The cells were evaluated after 0, 4, 7, and 10 days. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The mineralization assay was performed by staining MDPC-23 cells with Alizarin Red S solution. After cultivation, MDPC-23 cells were harvested for quantitative PCR or Western blotting. Analysis of variance was performed using StatView 5.0 software (SAS Institute Inc., Cary, NC, USA). Statistical significance was set at p < 0.05. The expression of NAMPT increased during the differentiation of murine odontoblast-like MDPC-23 cells. Furthermore, the up-regulation of NAMPT promoted odontogenic differentiation and accelerated mineralization through an increase in representative odontoblastic biomarkers, such as dentin sialophosphoprotein, dentin matrix protein-1, and alkaline phosphatase in MDPC-23 cells. However, treatment of the cells with the NAMPT inhibitor, FK866, attenuated odontogenic differentiation, as evidenced by the suppression of odontoblastic biomarkers. These data indicate that NAMPT regulated odontoblastic differentiation through the regulation of odontoblastic biomarkers. The increase in NAMPT expression in odontoblasts was closely related to the formation of the extracellular matrix and dentin via the Runx signaling pathway. Therefore, these data suggest that NAMPT is a critical regulator of odontoblast differentiation during tooth development.

Alpha-lipoic acid protects human dopaminergic neuronal cells against hydrogen peroxide-induced cell injury by inhibiting autophagy and apoptosis

Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and BclxL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.

Apoptotic activity of demethoxycurcumin in MG-63human osteosarcoma cells

Demethoxycurcumin (DMC), which is a curcuminoid found in turmeric, has anti-proliferative effects on cancer cells. However, the effect of DMC on osteosarcoma has not been established. The aim of this study was to examine the effects of DMC on cell growth and apoptosis induction in MG-63 human osteosarcoma cells. This study was investigated using 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromid assay, Live/Dead cell assay, 4’, 6-diamidino-2-phenylindole staining, and immunoblotting in MG-63 cells. DMC induced MG-63 cell death in a dosedependent manner, with an estimated IC50 value of 54.4 μM. DMC treatment resulted in nuclear condensation in MG-63 cells. DMC-induced apoptosis in MG-63 cells was mediated by the expression of Fas and activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting results showed that Bcl-2 and Bcl-xL were downregulated, while Bax and Bad were upregulated by DMC in MG-63 cells. These results indicated that DMC inhibits cell proliferation and induces apoptotic cell death in MG-63 human osteosarcoma cells via the death receptormediated extrinsic apoptotic pathway and mitochondria-mediated intrinsic apoptotic pathway.

Morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process / 대한해부학회지

The temporalis muscle is usually described as a single layer originating at the temporal line, converging to a tendon, and inserting onto a narrow site of the coronoid process. However, recent studies have shown that the temporalis muscle can be divided into two or three separate segments and the distal attachment continues inferiorly beyond the coronoid process. Therefore, the aims of this study were to analyze the morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process and to provide educational values. The temporalis muscle was carefully dissected in 26 cadavers and classified based on the muscle fascicle direction. Each divided part was sketched and measured based on bony landmarks to elucidate its tendinous insertion site onto the coronoid process, and the results obtained were reviewed through the literature. The temporalis muscle ends at two distinct terminal tendons with wider insertion sites than usually presented in textbooks and atlases and separates into two parts that combine to act as a single structural unit. The superficial part is a large fan-shaped muscle commonly recognized as the temporalis muscle. This converges infero-medially to form the superficial tendon and the lateral boundary of the retromolar triangle. Meanwhile, the deep part is a narrow vertically oriented rectangular muscle that converges postero-laterally to form the deep tendon and the medial boundary of the retromolar triangle. These results indicate that understanding the temporalis muscle’s insertion site onto the coronoid process will be useful clinically with educational values during surgical procedures.

Alpha-lipoic acid protects human dopaminergic neuronal cells against hydrogen peroxide-induced cell injury by inhibiting autophagy and apoptosis

Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and BclxL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.

Apoptotic activity of demethoxycurcumin in MG-63human osteosarcoma cells

Demethoxycurcumin (DMC), which is a curcuminoid found in turmeric, has anti-proliferative effects on cancer cells. However, the effect of DMC on osteosarcoma has not been established. The aim of this study was to examine the effects of DMC on cell growth and apoptosis induction in MG-63 human osteosarcoma cells. This study was investigated using 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromid assay, Live/Dead cell assay, 4’, 6-diamidino-2-phenylindole staining, and immunoblotting in MG-63 cells. DMC induced MG-63 cell death in a dosedependent manner, with an estimated IC50 value of 54.4 μM. DMC treatment resulted in nuclear condensation in MG-63 cells. DMC-induced apoptosis in MG-63 cells was mediated by the expression of Fas and activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting results showed that Bcl-2 and Bcl-xL were downregulated, while Bax and Bad were upregulated by DMC in MG-63 cells. These results indicated that DMC inhibits cell proliferation and induces apoptotic cell death in MG-63 human osteosarcoma cells via the death receptormediated extrinsic apoptotic pathway and mitochondria-mediated intrinsic apoptotic pathway.

Morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process / 대한해부학회지

The temporalis muscle is usually described as a single layer originating at the temporal line, converging to a tendon, and inserting onto a narrow site of the coronoid process. However, recent studies have shown that the temporalis muscle can be divided into two or three separate segments and the distal attachment continues inferiorly beyond the coronoid process. Therefore, the aims of this study were to analyze the morphology of the temporalis muscle focusing on the tendinous attachment onto the coronoid process and to provide educational values. The temporalis muscle was carefully dissected in 26 cadavers and classified based on the muscle fascicle direction. Each divided part was sketched and measured based on bony landmarks to elucidate its tendinous insertion site onto the coronoid process, and the results obtained were reviewed through the literature. The temporalis muscle ends at two distinct terminal tendons with wider insertion sites than usually presented in textbooks and atlases and separates into two parts that combine to act as a single structural unit. The superficial part is a large fan-shaped muscle commonly recognized as the temporalis muscle. This converges infero-medially to form the superficial tendon and the lateral boundary of the retromolar triangle. Meanwhile, the deep part is a narrow vertically oriented rectangular muscle that converges postero-laterally to form the deep tendon and the medial boundary of the retromolar triangle. These results indicate that understanding the temporalis muscle’s insertion site onto the coronoid process will be useful clinically with educational values during surgical procedures.

Inhibition of cell growth and induction of apoptosis by acacetin in FaDu human pharyngeal carcinoma cells

Acacetin, which is present in damiana (Turnera diffusa) and black locust (Robinia pseudoacacia), has several pharmacologic activities such as antioxidant, anti-inflammatory, and anti-proliferative effects on cancer cells. However, the effect of acacetin on head and neck cancers has not been clearly established. This study aimed to examine the effects of acacetin on cell growth and apoptosis induction in FaDu human pharyngeal carcinoma cells. These were investigated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, Live/Dead cell assay, 4′,6-diamidino-2-phenylindole dihydrochloride staining, caspase-3 and caspase-7 activation assay, and immunoblotting in FaDu cells. Acacetin induced FaDu cell death in a dose-dependent manner, with an estimated IC50 value of 41.9 µM, without affecting the viability of L-929 mouse fibroblasts as normal cells. Acacetin treatment resulted in nuclear condensation in the FaDu cells. It promoted the proteolytic cleavage of procaspase-3, -7, -8, and -9 with increasing amounts of the cleaved caspase isoforms in FaDu cells. Acacetin-induced apoptosis in FaDu cells was mediated by the expression of Fas and activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting showed downregulation of the anti-apoptotic mitochondrial proteins Bcl-2 and Bcl-xL, but upregulation of the mitochondria-dependent pro-apoptotic proteins Bax and Badin FaDu cells after acacetin treatment. These findings indicate that acacetin inhibits cell proliferation and induces apoptotic cell death in FaDu human pharyngeal carcinoma cells via both the death receptor-mediated extrinsic apoptotic pathway and the mitochondria-mediated intrinsic apoptotic pathway.

3-dimensional reconstruction of mandibular canal at the interforaminal region using micro-computed tomography in Korean

PURPOSE: The purpose of this study was to identify the complex course of the mandibular canal using 3D reconstruction of microCT images and to provide the diagram for clinicians to help them understand at the interforaminal region in Korean. MATERIALS AND METHODS: Twenty-six hemimandibles obtained from cadavers were examined using microCT, and the images were reconstructed. At both the midpoint of mental foramen and the tip of anterior loop, the bucco-lingual position, the height from the mandibular inferior border, the horizontal distance between two points, and position relative to tooth site on the mandibular canal were measured. The angle that the mental canal diverges from the mandibular canal was measured in posteriorsuperior and lateral-superior direction. RESULTS: The buccal distance from the mandibular canal was significantly much shorter than lingual distance at both the mental foramen and the tip of anterior loop. The mandibular canal at the tip of anterior loop was significantly located closer to buccal side and higher than at the mental foramen. And the mental canal most commonly diverged from the mandibular canal below the first premolar by approximately 50° posterior-superior and 41° lateral-superior direction, which had with a mean length of 5.19 mm in front of the mental foramen, and exited to the mental foramen below the second premolar. CONCLUSION: These results suggest that it could form a hazardous tetrahedron space at the interforaminal region, thus, the clinician need to pay attention to the width of a premolar tooth from the mental foramen during dental implant placement.

Morphological assessment of the anterior loop of the mandibular canal in Koreans / 대한해부학회지

The mandibular canal divides into the mental and incisive canals at the premolar region, forms the anterior loop which crosses anterior to the mental foramen, and turns back to reach the mental foramen. The aim of this study was to elucidate the general anatomical structure of the anterior loop of the mandibular canal using morphometry. Twenty-six hemimandibles from 19 cadavers (16 males, 3 females; mean age at death, 54.4 years) were studied by meticulous dissection with the aid of a surgical microscope. The location of the anterior loop, the diameters of the mandibular, mental, and incisive canals, and their distances from bony landmarks were measured using digital calipers. The anterior loop of the mandibular canal was located 3.05+/-1.15 mm (mean+/-SD) anterior to the anterior margin of the mental foramen and 2.72+/-1.41 mm inferior to the superior margin of the mental foramen, and was 4.34+/-1.46 mm long. The diameters of the mandibular, mental, and incisive canals were 2.8+/-0.49, 2.63+/-0.64, and 2.22+/-0.59 mm, respectively. The distances between the inferior border of the mandible and each of these canals were 7.82+/-1.52, 10.11+/-1.27, and 9.08+/-1.66 mm, respectively. The anterior loop of the mandibular canal was located a mean of 3.1 mm anterior and 2.7 mm inferior to the mental foramen, and continued upward and backward into the mental canal, and forward into the incisive canal. These detailed morphological features of the anterior loop of the mandibular canal represent useful practical anatomical knowledge regarding the interforaminal region.

Morphometric Analysis of the Facial Artery in Perioral Region / 체질인류학회지

The facial artery is the largest and main arterial supply of the face, and the inferior and superior labial arteries supply blood to the lower and upper lips and intersect on the opposite site. The aim of this study was to provide quantitative data on the course of facial artery and the distribution of inferior and superior labial artery in perioral region. The location, distance, course, and diameter of the facial artery, inferior labial artery, and superior labial artery were measured directly on 50 hemifacial cadavers of Koreans and statistically analyzed using oneway ANOVA. The facial artery was located 18.50 mm lateral to the mouth corners (Cheilions). The inferior labial artery at its origin was located 15.11 mm inferior and 19.63 mm lateral to the Cheilions. The superior labial artery at its origin was located 5.83 mm superior and 11.28 mm lateral to the Cheilions. The diameter of facial artery, inferior labial artery, and superior labial artery was 2.19, 1.56, and 1.48 mm, respectively. The courses of the facial artery and it's branches showed no significant differences on laterality except for the diameter of the superior labial artery (p=0.026). The buccal branch of facial artery was showed in 44% of the cases in the deep layer of perioral region. In conclusion, this study provides that the data will be useful in predicting the courses of the facial artery and helpful for reconstructive surgery in perioral region.

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

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.

MicroRNA Analysis during Cultured Odontoblast Differentiation

MicroRNAs (miRNAs, miRs) are about 21-25 nucleotides in length and regulate mRNA translation by base pairing to partially complementary sites, predominantly in the 3'-untranslated region (3'-UTR) of the target mRNA. In this study, the expression profile of miRNAs was compared and analyzed for the establishment of miRNA-related odontoblast differentiation using MDPC-23 cells derived from mouse dental papilla cells. To determine the expression profile of miRNAs during the differentiation of MDPC-23 cells, we employed miRNA microarray analysis, quantitative real-time PCR (qRT-PCR) and Alizaline red-S staining. In the miRNA microarray analysis, 11 miRNAs were found to be up- or down-regulated more than 3-fold between day 0 (control) and day 5 of MDPC-23 cell differentiation among the 1,769 miRNAs examined. In qRT-PCR analysis, the expression levels of two of these molecules, miR-194 and miR-126, were increased and decreased in the control MDPC-23 cells compared with the MDPC-23 cells at day 5 of differentiation, respectively. Importantly, the overexpression of miR-194 significantly accelerated mineralization compared with the control cultures during the differentiation of MDPC-23 cells. These results suggest that the miR-194 augments MDPC-23 cell differentiation, and potently accelerates the mineralization process. Moreover, these in vitro results show that different miRNAs are deregulated during the differentiation of MDPC-23 cells, suggesting the involvement of these genes in the differentiation and mineralization of odontoblasts.

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.

Angulation between Long Axis of Anterior Teeth and Alveolar Process, and Thickness of Alveolar Bone / 체질인류학회지

The main aim of dental implant placement on the anterior region is to recover the function and esthetics. Therefore, this study examined the angulation between the long axis of the anterior teeth and the alveolar process, and thickness of the alveolar bone on the anterior region. Twenty-five cadaver heads (18 maxillae and 23 mandibles) were examined (16 male and 9 female, mean: 56.7 years). The angulation between the long axis of the anterior teeth and the alveolar process was measured, and the alveolar bone thickness was measured in the three levels (crest; C, middle; M, apex; A) on the labial and lingual sides. All data was analyzed statistically using one-way ANOVA. The maxillary anterior teeth showed two to three times more lingual inclination than the mandibular teeth. The difference in maxillary alveolar bone thickness on the labial and lingual sides was significant in all levels, particularly in the apex. The mandibular alveolar bone thickness on the labial and lingual side was significantly different only in the apex. In conclusion, the alveolar bone thickness on the anterior region was too thin, and the long axis of the maxillary anterior teeth showed more lingual inclination than the alveolar process. Therefore, clinicians need to be a detailed assessment of the labial alveolar bone for dental implant placement.

Angulation between Long Axis of Anterior Teeth and Alveolar Process, and Thickness of Alveolar Bone / 체질인류학회지

The main aim of dental implant placement on the anterior region is to recover the function and esthetics. Therefore, this study examined the angulation between the long axis of the anterior teeth and the alveolar process, and thickness of the alveolar bone on the anterior region. Twenty-five cadaver heads (18 maxillae and 23 mandibles) were examined (16 male and 9 female, mean: 56.7 years). The angulation between the long axis of the anterior teeth and the alveolar process was measured, and the alveolar bone thickness was measured in the three levels (crest; C, middle; M, apex; A) on the labial and lingual sides. All data was analyzed statistically using one-way ANOVA. The maxillary anterior teeth showed two to three times more lingual inclination than the mandibular teeth. The difference in maxillary alveolar bone thickness on the labial and lingual sides was significant in all levels, particularly in the apex. The mandibular alveolar bone thickness on the labial and lingual side was significantly different only in the apex. In conclusion, the alveolar bone thickness on the anterior region was too thin, and the long axis of the maxillary anterior teeth showed more lingual inclination than the alveolar process. Therefore, clinicians need to be a detailed assessment of the labial alveolar bone for dental implant placement.

Localization of the Mental and Infraorbital Foramen with related to the Soft-tissue Landmarks

During maxillofacial surgery, the infraorbital and mental nerves are blocked at eac foramen to induce local anesthesia. This study examined the relative locations of the infraorbital foramen (IOF) and mental foramen (MF) based on soft-tissue landmarks. Twenty-eight hemifacial cadavers were dissected to expose the IOF and MF. The distances between the bilateral IOFs, the bilateral MFs, the alae of the nose (alares), and the corners of the mouth (cheilions) were measured directly on cadavers by using a digital vernier caliper. The vertical and horizontal distances of the IOF and MF relative to the alare and cheilion were measured indirectly on digital photographs using Adobe Photoshop (Adobe, CA, USA). The distance between the bilateral IOFs (58.09 +/- 4.04 mm) was longer than the distance between the bilateral MFs (50.32 +/- 1.93 mm). The distances between the bilateral alares and cheilions were 41.22 +/- 3.44 mm and 58.43 +/- 6.62 mm, respectively. The IOF was located 12.92 +/- 3.75 mm superior and 7.88 +/- 2.56 mm lateral to the alare, and the vertical angle (Angle 1) between these structures was 31.67 +/- 13.36degrees superolaterally. The MF was located 21.83 +/- 3.26 mm inferior and 5.56 +/- 3.37 mm medial to the cheilion, and the vertical angle (Angle 2) between these structures was 14.05 +/- 10.12degrees inferomedially. In conclusion, these results provide more detailed information about the locations of the IOF and MF relative to soft-tissue landmarks.

Morphometric Analysis of the Supraorbital and Infraorbital Foramina Based on the Medial Canthus in Koreans / 체질인류학회지

Knowledge of the location of the maxillo-facial foramina is essential for regional nerve blocks and endoscopic surgical procedures to avoid nerve injury passing through these foramina. The purposes of this study were to determine the locations of the supraorbital foramen (SOF) and the infraorbital foramen (IOF) related to medial canthus (MC), and to analyze the morphology of these foramina. Thirty-two embalmed cadavers (64 sides, mean age: 64.1 years) and 33 dry skulls (66 sides) were used. The distances from the SOF, IOF, and MC to facial midline were directly measured on the cadavers using digital Vernier caliper. The vertical and horizontal distances of the SOF and IOF relative to the medial canthus were indirectly measured on the digital photographs using image analyzer software. The vertical and horizontal diameters of the IOF, and its location in relation to maxillary tooth were evaluated on the dry skull. Statistical analysis was performed using one-way ANOVA with declaration of significant difference when P<0.05. The mean distances of SOF, MC, and IOF to the facial midline were 24.13 mm, 15.00 mm, and 29.11 mm, respectively. The SOF was located 18.99 mm superior and 9.05 mm lateral to the medial canthus. The distance between the medial canthus and the SOF was 22.67 mm, and the vertical angle (Angle 1) between these structures was 24.36degrees superolaterally. The IOF was located 26.69 mm inferior and 13.53 mm lateral to the medial canthus. The distance between the medial canthus and IOF was 30.82 mm and the vertical angle (Angle 2) between these structures was 26.59degrees inferolaterally. In the this study, spraorbital notch (SON) was found more frequently than the SOF. The mean vertical and horizontal diameters of IOF were 3.36 mm, 3.45 mm, respectively. IOF was most commonly found in the same vertical plane with the second upper premolar. In conclusion, these results are important for performing local anesthetic, facial plastic surgery, and other invasive procedures in the forehead and periorbital region to prevent injury of neurovascular bundles passing through these foramina.

Cortical Bone Thickness for Mini-implant Placement in Korean

Recently, mini-implant is popular in the orthodontic treatment due to its simplicity and convenient surgical procedure. The objective of this study is to provide the anatomical guideline for mini-implant placement by analysing the cortical bone thickness in Korean. Hemi-sections of sixteen maxillae and twenty-two mandibles with normal teeth were used. Interdental areas between the 1st premolar and the 2nd premolar (Group 1), the 2nd premolar and the 1st molar (Gruop 2), and the 1st molar and the 2nd molar (Group 3) were sectioned and then scanned. After setting the axis of teeth, the cortical bone thickness was measured at the distance of 2 mm, 4mm, 6 mm, and 8 mm from alveolar crest. The mean thickness of cortical bone in the maxilla according to distance from alveolar crest was 1.30 +/- 0.63 mm (2 mm), 1.49 +/- 0.62 mm (4mm), 1.72 +/- 0.64 mm (6mm), and 1.90 +/- 0.90 mm (8 mm) at the buccal side and 1.33 +/- 0.47 mm, 1.31 +/- 0.45 mm, 1.37 +/- 0.55 mm, and 1.39 +/- 0.58 mm at the palatal side. In the mandible, that was 3.14 +/- 1.71 mm, 4.31 +/- 2.22 mm, 4.23 +/- 1.94 mm, and 4.30 +/- 1.57 mm at the buccal side and 1.98 +/- 0.88 mm, 2.79 +/- 1.01 mm, 3.35 +/- 1.27 mm, and 3.93 +/- 1.38 mm at the lingual side. The buccal cortical bone thickness in the maxilla was decreased from Group 1 to Group 3, while the thickness of palatal side was no change. In the mandible, it did not show a tendency at the buccal side and it was decreased from Group 1 to Group 3 without significant difference at the lingual side. Therefore, the buccal side of the Group 1 and Group 2 in both the maxilla and mandible seems to be the most appropriate site for a mini-implant placement with taking the stability and retention.

Effects of Chitosan on the Differentiation of MDPC-23 Cells

The effects of chitosan upon the experimentally induced differentiation of MDPC-23 cells, derived from mouse dental papilla cells, were investigated by RT-PCR, observations of cell morphology and Alizaline red-S staining. Chitosan was found to significantly increase and accelerate the expression of ALP mRNA but decrease the ColI transcript levels, as compared with the control, in a time-dependent manner during the differentiation of MDPC-23 cells. Chitosan also significantly downregulated ON mRNA expression and accelerated mineralization in differentiating MDPC-23 cells. These results suggest that chitosan facilitates odontoblast differentiation and mineralization and may have potential clinical applications as a dentin regeneration material.