Treatment effects of mandibular total arch distalization using a ramal plate / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate treatment effects after distalization of the mandibular dentition using ramal plates through lateral cephalograms. METHODS: Pre- and post-treatment lateral cephalograms and dental casts of 22 adult patients (11 males and 11 females; mean age, 23.9 ± 5.52 years) who received ramal plates for mandibular molar distalization were analyzed. The treatment effects and amount of distalization of the mandibular molars were calculated and tested for statistical significance. The significance level was set at p < 0.001. RESULTS: The mandibular first molar distalization at the crown and root were 2.10 mm (p < 0.001) and 0.81 mm (p = 0.011), respectively. In the evaluation of skeletal variables, there was a significant increase in the Wits appraisal (p < 0.001). In the evaluation of the soft tissue, there was no significant effect on upper lip position, but the lower lips showed a significant retraction of 2.2 mm (p < 0.001). CONCLUSIONS: The mandibular molars showed a significant amount of distalization accompanied by limited extrusion and mesiobuccal rotation of the crowns. A ramal plate may be a viable device for mandibular total arch distalization in Class III patients who are reluctant to undergo orthognathic surgery.

The Vertical Changes of Lip and Perioral Soft Tissue Following Orthognathic Surgery in Skeletal Class III Patients by a Cephalometric Analysis of Cone Beam Computed Tomography

Three-dimensional analysis of pharyngeal airway change of skeletal class III patients in cone beam computed tomography after bimaxillary surgery

INTRODUCTION: To evaluate the 3-dimensional changes in the pharyngeal airway of skeletal class III patients after bimaxillary surgery. MATERIALS AND METHODS: The study sample consisted of 18 Korean patients that had undergone maxillary setback or posterosuperior movement and mandibular bilateral sagittal split osteotomy setback surgery due to skeletal class III malocclusion (8 males, 10 females; mean age of 28.7). Cone beam computed tomography was taken 1 month before and 6 months after orthognathic surgery. Preoperative and postoperative volumes of the nasopharyngeal, oropharyngeal, and laryngopharyngeal airways and minimum axial areas of the oropharyngeal and laryngopharyngeal spaces were measured. Moreover, the pharyngeal airway volume of the patient group that had received genioplasty advancement was compared with the other group that had not. RESULTS: The nasopharyngeal and laryngopharyngeal spaces did not show significant differences before or after surgery. However, the oropharyngeal space volume and total volume of pharyngeal airway decreased significantly (P<0.05). The minimum axial area of the oropharynx also decreased significantly. CONCLUSION: The results indicate that bimaxillary surgery decreased the volume and the minimum axial area of the oropharyngeal space. Advanced genioplasty did not seem to have a significant effect on the volumes of the oropharyngeal and laryngopharyngeal spaces.

A clinical evaluation of efficacy of an office bleaching gel containing 30% hydrogen peroxide / 대한치과보존학회지

This study evaluated the efficacy of an office bleaching gel (RemeWhite, Remedent Inc., Deurle, Belgium) containing 30% hydrogen peroxide. 31 volunteers were recieved office bleaching with the RemeWhite for 3 times at one visit, total 2 visits. As control group, the same gel in which hydrogen peroxide was not included was applied to 31 volunteers with the same protocol. The shade change (DeltaE*, color difference) of 12 anterior teeth was measured using Colorimerter and Vitapan classical shade guide. The shade change of overall teeth in the experimental group was significantly greater than that in the control group which was measured using Colorimeter. There was also a significant difference between baseline and 14 weeks or 26 weeks though color rebounding phenomenon occurred as time went by. Small shade change difference can be measured accurately using Colorimeter than using Vitapan classical shade guide.

A clinical evaluation of safety of an office bleaching gel containing 30% hydrogen peroxide / 대한치과보존학회지

This study evaluated the safety of an office bleaching gel (RemeWhite, Remedent Inc., Deurle, Belgium) containing 30% hydrogen peroxide. 37 volunteers were recieved office bleaching with the RemeWhite for 3 times at one visit, total 2 visits. As control group, the same gel in which hydrogen peroxide was not included was applied to 34 volunteers with the same protocol. There was no difference between experimental group and control group using electric pulp test. In the result of gingival inflammation index and tooth sensitivity test, there was mild pain response in experimental group but it disappeared as time went by. Therefore, safety of the office bleaching gel containing 30% hydrogen peroxide was confirmed.

Stress distribution pattern of the different diameter and length of short implants according to the bone quality: 3-D Finite Elements Analysis

Osteogenesis by BMP-2 in adult stem cell derived from buccal fat pad

Bone morphogenetic proteins (BMPs) in combination with stem cells gain more significance for their use in bone tissue engineering. The mesenchymal stem cell can be differentiated into osteoblast by the treatment of BMP. The aim of this study is to characterize the osteogenic differentiation process of adult stem cells derived from buccal fat pad according to BMP-2 within culture media and decide the appropriate concentration of BMP-2 to facilitate osteogenesis. The authors procured the stem cell from buccal fat pad and analyzed for presence of stem cell by flow cytomety against CD-34, CD-105 and STRO-1. The buccal fat derived stem cells (BFDC) were treated by application of the different concentration with BMP-2 of 0, 10, 50, 100 and 200ng/ml, respectively. And their ability to differentiate into osteogenic pathway were checked by alkaline phosphatase(ALP) staining, Alizarin red staining and RT-PCR for osteocalcin(OC) gene expression at 7, 14 and 21day of culture. Flow cytometric analysis and biochemical assays demonstrated that BFDC might be a distinguished stem cells, and mineralization was accompanied in proportion to BMP-2 concentration. However, with 100ng/ml concentration of BMP-2, the BFDC demonstrated most efficent staining pattern of ALP and Alizarin red. The feasibilty of the osteogenic differentiation in the group of both 50ng/ml and 200ng/ml of BMP-2 showed similar activity and relatively weaker than that of 100ng/ml. These results suggest that the BMP-2 stimulate osteogenesis by BFDC effectively and that bone induction might be controlled through negative regulatory feedback in higher concentration.

The hypermethylation of E-cadherin gene in oral squamous cell carcinoma

Loss of E-cadherin (E-cad) expression has been found in multiple cancers and is postulated to facilitate tumor cell dissociation and metastais. Promotor methylation may provides an alternative pathway for loss of gene function. This study evaluated the role of hypermethylation in the down-regulation of E-cad in oral squamous cell carcinoma (OSCC). We examined the E-cad expression by immunohistochemical staining and detected methylation status by methylation-specific polymerase chain reaction (MSP) in 20 OSCC tissues. Overally, 12 (60 %) cases of hypermethylation of E-cad were detected and we found there were no correlation between methylation and age, histologic grade, lympn node metastasis, tumor size and clinical stage. However, Eleven (73.3 %) of 15 samples which was negative for E-cad staining showed hypermethylation of E-cad promotor region. On the other hand, only one (20 %) of 5 E-cad positive sample was observed with methylated status. The underexpression of E-cad was found to be related to promotor hypermethylation (p=0.035). In conclusion, we suggest that hypermethylation play a role in inactivation of E-cad gene and may be a appreciable biomarker for diagnosis and treatment of OSCC.

The hypermethylation of E-cadherin gene in oral squamous cell carcinoma

Loss of E-cadherin (E-cad) expression has been found in multiple cancers and is postulated to facilitate tumor cell dissociation and metastais. Promotor methylation may provides an alternative pathway for loss of gene function. This study evaluated the role of hypermethylation in the down-regulation of E-cad in oral squamous cell carcinoma (OSCC). We examined the E-cad expression by immunohistochemical staining and detected methylation status by methylation-specific polymerase chain reaction (MSP) in 20 OSCC tissues. Overally, 12 (60 %) cases of hypermethylation of E-cad were detected and we found there were no correlation between methylation and age, histologic grade, lympn node metastasis, tumor size and clinical stage. However, Eleven (73.3 %) of 15 samples which was negative for E-cad staining showed hypermethylation of E-cad promotor region. On the other hand, only one (20 %) of 5 E-cad positive sample was observed with methylated status. The underexpression of E-cad was found to be related to promotor hypermethylation (p=0.035). In conclusion, we suggest that hypermethylation play a role in inactivation of E-cad gene and may be a appreciable biomarker for diagnosis and treatment of OSCC.

Differentiation of adult stem cell derived from buccal fat pad into osteoblast

For the repairing of bone defect, autogenous or allogenic bone grafting remains the standard. However, these methods have numerous disadvantages including limited amount, donor site morbidity and spread of diseases. Tissue engineering technique by culturing stem cells may allow for a smart solution for this problem. Adipose tissue contains mesenchymal stem cells that can be differentiate into bone, cartilage, fat or muscle by exposing them to specific growth conditions. In this study, the authors procured the stem cell from buccal fat pad and differentiate them into osteoblast and are to examine the bone induction capacity. Buccal fat-derived cells (BFDC) were obtained from human buccal fat pad and cultured. BFDC were analyzed for presence of stem cell by immunofluorescent staining against CD-34, CD-105 and STRO-1. After BFDC were differentiated in osteogenic medium for three passages, their ability to differentiate into osteogenic pathway were checked by alkaline phosphatase (ALP) staining, Alizarin red staining and RT-PCR for osteocalcin (OC) gene expression. Immunofluorescent and biochemical assays demonstrated that BFDC might be a distinguished stem cells and mineralization was accompanied by increased activity or expression of ALP and OC. And calcium phosphate deposition was also detected in their extracelluar matrix. The current study supports the presence of stem cells within the buccal fat pad and the potential implications for human bone tissue engineering for maxillofacial reconstruction.

Construction of recombinant HSCC-1 adenovirus vector for oral cancer gene therapy

Expression of e-cadherin with correlation to clinicopathologic parameters in oral squamous cell carcinoma

It becomes more concerned that the cell adhesion molecule plays an important role in the process of malignant transformation and tumor behaviors including invasive growth and metastasis. It is postulated if the expression of adhesion molecule is reduced in tumor tissue, the tumor cell will be undifferentiated and lose their cell adhesion ability and polarity. So the tumor cells lost the adhesion of cell to cell and to basement membrane that they became more aggressive. Reduced cadherin expression enhances invasiveness through infiltrative growth and metastasis of tumor cells is well known and mostly accepted in many epithelia tumors. We explored the expression of E-cadherin by immunohistochemical staining in 50 oral squamous cell carcinomas and investigated the correlation between the expression of E-cadherin and clinicopathologic parameters and prognosis. The expression of E-cadherin was reduced in 40/50(80%) of primary tumors, and 21/22(95.5%) of lymph nodes. The reduced expression of the E-cadherin was associated with lymph node metastasis(P=0.029), invasive mode(P=0.030) and marginal status(P=0.038). Survival analysis showed that predictive period of E-cadherin reduced group(37 months) was lower than that of E-cadherin preserved group(60 months), but there was no statistical significant difference.

Induction of apoptosis in oral cancer cell line through an recombinant HCCS-1 adenovirus

Despite advances in surgery, radiotherapy, and chemotherapy, the survival of patients with oral squamous cell carcinoma has not significantly improved over the past several decades. Gene therapy is currently under investigation and shows us new possibility of cancer curing method. This experiment was undergone to find out the cell growth inhibition effect and evidence of apoptosis by HCCS-1(human cervical cancer suppressor-1), one of the candidates of tumor suppressor gene, transducted to human oral cancer cell line. To determine the efficiency of the adenovirus as a gene delivery vector cell line was transducted with LacZ gene and analysed with X-gal staining. Northern blot was performed to confirm the transfection with HSCC-1 gene and cell viability was assessed by cell cytotoxicity assay using cell count kit(CCK). To show the evidence of apoptosis, DNA fragmentation assay and flow cytometry(FACS) were performed. We had successfully construct the recombinant HSCC-1 adenovirus(Ad5CMV-HCCS-1), and importation efficiency was 20% at 2 MOI(multiplicity of infection), 80% at 20 MOI. Northern blot analysis showed that a single 0.6kb mRNA transcript was expressed in Ad5CMV-HCCS-1 transducted cell lines. As a result of CCK, when comparing to control subjects, transducted group showed 50% growth inhibition. In DNA fragmentation assay, according to increasing of MOI, DNA volume was diminished. In FACS analysis, DNA distribution showed fragmentation.This results imply that HCCS-1gene has growth inhibition effect in human oral cancer cell lines through apoptosis induction.

Current review of molecular biology in distraction osteogenesis

Distraction osteogenesis is a well-established clinical treatment for limb length discrepancy and skeletal deformities. Appropriate mechanical tension-stress is believed not to break the callus but rather to stimulate osteogenesis. In contrast to fracture healing, the mode of bone formation in distraction osteogenesis is primarily intramembranous ossification. Although the biomechanical, histological, and ultrastructural changes associated with distraction osteogenesis have been widely described, the basic biology of the process is still not well known. Moreover, the molecular mechanisms in distraction osteogenesis remain largely unclear. Recent studies have implicated the growth factor cascade is likely to play an important role in distraction. And current reserch suggested that mechanical tension-stress modulates cell shape and phenotype, and stimulates the expression of the mRNA for bone matrix proteins. This article presents the hypotheses and current research that have furthered knowledge of the molecular biology that govern distraction osteogenesis. The gene regulation of growth factors and extracellular matrix proteins during distraction osteogenesis are discussed in this article. It is believed that understanding the biomolecular mechanisms that mediate distraction osteogenesis may guide the development of targeted strategies designed to improve distraction osteogenesis and accelerate bone healing.

Immunohistochemical Study on the Expression of c-erbB-2 Oncoprotein in the Odontogenic cysts

To investigate epithelial cell proliferation reactivity in the odontogenic cysts, the expression of c-erbB-2 oncoprotein by epithelial lining was studied in odontogenic keratocyst(OKC, n=10), dentigerous cyst(DC, n=12), radicular cyst(RC, n=12) and normal dental follicle(n=7). The c-erbB-2 immunoreactivity was studied using a streptavidine- biotin- peroxidase method with polyclonal rabbit anti-human antibody to c-erbB-2 oncoprotein which is known to react with formalin fixed, paraffin-embedded sections and the intensity of staining was determined by manually. In all of 10(100%) OKCs, showed positive expression for c-erbB-2 oncoprotein compared with 10/12(83.3%) in DCs, 11/12(91.7%) in RCs and 5/7(71.4%) in normal dental follicles. The expression within OKC was higher than that of DC, RC and dental follicle but statistically not significant(p>0.05) and but may reflects underlying genetic defect. These results demonstrate differences in c-erbB-2 expression between the epithelial linings of the three major odontogenic cyst types, indicating differences in proliferation activity and differentiation processes within these lesions. And, in particular, these results are able to explain the peculiar aggressive growth pattern of OKC.