• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.3
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• pp.191-198
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• 2007

The p53 which is well known as tumor suppressor gene is located at 17p13. p53 is a sequence-specific DNA binding transcription factor that responds to certain cytotoxic stresses, such as DNA damage, by enhancing the transcription of genes that regulate cell-cycle progression as well as programmed cell death. The p63 gene that is located at 3q27-29, is recognized members of the p53 family, and responsible for the transcription of 6 isoforms. Three isoforms ($TAp63{\alpha}$, $TAp63{\beta}$, $TAp63{\gamma}$) contain an N-terminal transactivation (TA) domain and can induce apoptosis. The other 3 isoforms (${\Delta}Np63{\alpha}$, ${\Delta}Np63{\beta}$, ${\Delta}Np63{\gamma}$) lack the TA domain and may function in a dominant-negative fashion by inhibiting the transactivation functions of p53 and TAp63 proteins, and thus act as oncoproteins. A number of studies have investigated the role of p63 in human squamous cell carcinomas from different organs. Only a few studies have examined ${\Delta}Np63$ isoform in oral squamous cell carcinoma including normal epithelium. This study aimed to evaluate expression of ${\Delta}Np63$ isoform in human oral squamous cell carcinoma tissue and normal mucosa. The 3 cases of well differenciated oral squamous cell carcinoma specimen including adjacent normal mucosa were examined, and immunohistochemical study with monoclonal antibody(4A4) and tumor cell apoptosis analysis with Transmission Electon Microscopy were studied. And, RT-PCR analysis was done for expression of ${\Delta}Np63$ isoform. The results were as followed. 1. Normal gingiva showed the restricted p63 expression in basal cell layer. 2. Well differentiated squamous cell carcinoma showed mainly p63 expression in overall area of malignancy, especially in basal cell layer to adjacent stromal tissue. 3. Tumor cells around keratinized area with no p63 expression disclosed less micro-organelle in decreased size cytoplasm and severe chromatin margination with nuclear destruction that means apoptosis. 4. Comparison of mRNA expression of ${\Delta}Np63$ isoform by RT-PCR showed variable expression of ${\Delta}Np63$ isoform, but ${\Delta}Np63{\alpha}$ was most highly expressed in all 3 tumor specimen. From theses results, it should be suggested that ${\Delta}Np63$ isoform expression in well differentiated squamous cell carcinoma was closely related to tumor oncogenesis, expecially overexpression of ${\Delta}Np63{\alpha}$ is a most important factor in tumor genesis of oral squamous cell carcinoma.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.2
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• pp.141-150
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• 2008

We studied 1809 oral cancer patients who visited and were treated in 2002 at the 148 institutions certified as training facilities by the Japanese Society of Oral and Maxillofacial Surgeons, which is composed of 39 dental university hospitals, 44 medical university hospitals, 64 general hospitals, and 1 unknown institution. The patients consisted of 1071 (59.2%) males and 738 (40.8%) females (male:female ratio, 1.45:1), who had a mean age of 65.2 years old. The tongue (40.2%) was the most common site affected, followed by the gingiva (32.7%), buccal mucosa (10.1%), and oral floor (9.0%). There were 6 cases of intraoral multiple cancer. In histopathological examinations, squamous cell carcinoma (88.7%) was the most common type found, followed by adenoid cystic carcinoma (2.1%), and mucoepidermoid carcinoma (1.7%). In addition, non-epithelial tumors comprised 1.8%, among which malignant melanoma was the most common type. Cases classified as T2N0 were the most common (32.1%), followed by T1N0 (21.4%), T4N0 (8.0%), and T2N1 (7.6%). Distant metastasis occurred in 17 patients (1.0%). The sizes of the non-epithelial malignant tumors ranged from 1.0 to 7.0 cm, with a mean size of 3.7 cm.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.821-838
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• 1999

On the basis of the evidences that electrical stimulation could enhance proliferation and differentiation of bone cells and promote healing and regeneration of bone, this study was performed to investigate the effects of electrical stimulation on human periodontal ligament cells and gingival fibroblasts in vitro, which also have important roles in regeneration of periodontium, and to evaluate the potential of clinical application of electrical stimulation. Human periodontal ligament cells and gingival fibroblasts were primarily cultured from the root surface of extracted premolar and the adjacent gingiva without periodontal diseases. In control group, the cells ($5{\times}10^4$ cells/ml)were incubated only in Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum. In test groups, electrical stimulation was given at the current intensity of $0.25{\mu]A$(test group 1), $1.0{\mu}A$(test group 2), and $2.5{\mu}A$(test group 3) for 12 hours to the same culture media with the control group. After 12 hour exposure of electrical stimulation, the cells were incubated for 2 and a half days(60 hours), and then each group of cells was analyzed for cell proliferation, protein level, and activity of alkaline phosphatase. The results were as follows ; 1. The Rate of cell proliferation of every test group increased significantly in both periodontal ligament cells and gingival fibroblasts, and in periodontal ligament cells, test group 3 showed significantly increased proliferation compared to the other test groups(p<0.05). 2. In the protein levels, neither periodontal ligament cell nor gingival fibroblast showed statistically significant differences between control and test groups. 3. The activity of alkaline phosphatase in periodontal ligament cells increased significantly in all test groups(p<0.05), but there were no significant differences between 3 test groups. In gingival fibroblasts, the activity of alkaline phosphatase increased significantly only in test group 3(p<0.05). From the above results, it is concluded that electrical stimulation may have beneficial effects on the regeneration of destructed periodontal tissue in regard of the stimulation of periodontal ligament cells and gingival fibroblasts as well as electrically stimulated bone formation that has been known, and that electrical stimulation may have the potential of clinical application.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.151-156
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• 2006

Purpose : The aim of this study was to determine the accuracy of clinical and radiologic assessments in detecting positive cervical lymph nodes in oral cancer. Materials and Methods : We had reviewed the preoperative clinical, radiologic and postoperative histopathologic reports of 46 patients who had been diagnosed as oral cancer and underwent surgical excision combined with neck dissection (52 sides of neck) in the Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University from the July 1, 1992 to the April 30, 1999. Results : The results were as follows 1. The male to female ratio was 4.38 : 1 and the mean age was 57. 2. Sensitivity values for the preoperative assessment of cervical lymph node metastasis in oral cancer were 62.5 % in clinical examination and 50.0 % in radiologic assessments. Specificity values were 77.8 % in clinical examination and 94.4 % in radiologic assessments. 3. False positive values were 44.4 % in clinical examination and 20.0 % in radiologic assessments. False negative values were 17.6 % in clinical and 19.0% in radiologic assessments. 4. Overall efficiency values were 73.1 % in clinical examination and 80.8 % in radiologic assessments. Summary : There were some limits on the accuracy of clinical and radiologic assessments in the preoperative detection of the cervical lymph nodes in oral cancer. To improve the accuracy, it is important to communicate between clinician and radiologist, and adjunctive diagnostic measures, ultrasound and fine needle aspiration cytology, were helpful increasing the overall efficiency. In the high risk sites (oral tongue and floor of the mouth) the false negative value is higher and the overall efficiency in radiologic evaluation is lower than those of the low risk sites (gingiva and alveolar ridge, retromolar trigone and buccal mucosa ). The elective neck dissection should be considered in the high risk sites.

• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.783-796
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• 2006

The periodontium is a topographically complex organ consisting of epithelial tissue, soft and mineralized tissues. Structures comprising the periodontium include the gingiva, periodontal ligament (PDL) , cementum and the alveolar bone. The molecular mechanism of differentiation in PDL fibroblast cells remain unclear. Amino acid transporters play an important role in supplying nutrition to normal and cancer cells and for cell proliferation. Amino acid transport system L is a major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The system L is divided into two major subgroups, the L-type amino acid transporter 1 (LAT1) and the L-type amino acid transporter 2 (LAT2). In this study, the expression pattern of amino acid transport system L was, therefore, investigated in the differentiation of PDL fibroblast cells. To determine the expression level of amino acid transport system L participating in intracellular transport of amino acids in the differentiation of PDL fibroblast cells, it was examined by RT-PCR, observation of cell morphology, Alizaline red-S staining and uptake analysis after inducing experimental differentiation in PDL fibroblast cells isolated from mouse molar teeth. The results are as follows. 1. The LAT1 mRNA was expressed in the early stage of PDL fibroblast cell differentiation. This expression level was gradually reduced by differentiation- inducing time and it was not observed after the late stage. 2. The expression level of LAT2 mRNA was increased in time-dependent manner during differentiation induction of PDL fibroblast cells. 3. There was no changes in. the expression level of 4F2hc mRNA, the cofactor of LAT1 and LAT2, during differentiation of PDL fibroblast cells. 4. The expression level of ALP mRNA was gradually increased and the expression level of Col I mRNA was decreased during differentiation of PDL fibroblast cells. 5. The L-leucine transport was reduced by time from the early stage to the late stage in PDL fibroblast cell differentiation. As the results, it is considered that among neutral ammo acid transport system L in differentiation of PDL fibroblast cells, the LATl has a key role in cell proliferation in the early stage of cell differentiation and the LAT2 has an important role in the late stage of cell differentiation for providing cells with neutral amino acids including several essential amino acids.

• Journal of Periodontal and Implant Science
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• v.41 no.4
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• pp.176-184
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• 2011

Purpose: The final goal of regenerative periodontal therapy is to restore the structure and function of the periodontium destroyed or lost due to periodontitis. However, the role of periosteum in periodontal regeneration was relatively neglected while bone repair in the skeleton occurs as a result of a significant contribution from the periosteum. The aim of this study is to understand the histological characteristics of periosteum and compare the native periosteum with the repaired periosteum after elevating flap or after surgical intervention with flap elevation. Methods: Buccal and lingual mucoperiosteal flaps were reflected to surgically create critical-size, "box-type" (4 mm width, 5 mm depth), one-wall, intrabony defects at the distal aspect of the 2nd and the mesial aspect of the 4th mandibular premolars in the right and left jaw quadrants. Animals were sacrificed after 24 weeks. Results: The results from this study are as follows: 1) thickness of periosteum showed difference as follows (P<0.05): control group ($0.45{\pm}0.22$ mm)> flap-elevation group ($0.36{\pm}0.07$ mm)> defect formation group ($0.26{\pm}0.03$ mm), 2) thickness of gingival tissue showed difference as follows (P<0.05): defect formation group ($3.15{\pm}0.40$ mm)> flap-elevation group ($2.02{\pm}0.25$ mm) > control group ($1.88{\pm}0.27$ mm), 3) higher cellular activity was observed in defect formation group and flap-elevation groups than control group, 4) the number of blood vessles was higher in defect formation group than control group. Conclusions: In conclusion, prolonged operation with increased surgical trauma seems to decrease the thickness of repaired periosteum and increase the thickness of gingiva. More blood vessles and high cellular activity were observed in defect formation group.

• Journal of Periodontal and Implant Science
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• v.39 no.2
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• pp.111-118
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• 2009

Purpose: The integrity of interproximal hard/soft tissue has been widely accepted as the key determinant for success or degree of root coverage following the connective tissue graft. However, we reason that the gingival biotype of an individual, defined as the distance from the interproximal papilla to gingiva margin, may be the key determinant that influence the extent of root coverage regardless of traditional classification of gingival recession. Hence, the present study was performed with an aim to verify that individual gingival scalloping pattern inherent from biotype influence the level of gingival margin following the connective tissue graft for root coverage. Methods: Test group consisted of 43 single-rooted teeth from 21 patients (5 male and 16 female patients, mean age: 36.6 years) with varying degrees of gingival recession requiring connective tissue graft; 20 teeth of Miller class I and 23 teeth of Miller class III gingival recession, respectively. The control group consisted of contralateral teeth which did not demonstrate apparent gingival recession, and thus not requiring root coverage. For a biotype determination, an imaginary line connecting two adjacent papillae of a test tooth was drawn. The distance from this line to gingival margin at mid-buccal point and this distance (P-M distance) was designated as "gingival biotype" for a given individual. The distance was measured at baseline and 3 to 6 months examinations postoperatively both in test and control groups. The differences in the distance between Miller class I and III were subject to statistical analysis by using Student.s t-test while those between the test and control groups within a given patient were by using paired t-test. Results: The P-M distance at 3 to 6 months postoperatively was not significantly different between Miller class I and Miller class III. It was not significantly different between the test and control group in a given patient, either, both in Miller class I and III. Conclusions: The amount of root coverage following the connective tissue graft was not dependent on Miller's classification, but rather was dependent on P-M distance, strongly implying that the gingival biotype of a given patient may play a critical impact on the level of gingival margin following connective tissue graft.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.657-661
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• 2005

Various chemotherapeutic agents have been recommended for pulpotomy of primary teeth, and there are formocresol, ferric sulfate, and calcium hydroxide. Of those, formocresol has fixation effect of pulp tissue and high clinical success rate, so it is most commonly used agent. But formocresol has strong cytotoxic effects, thus many articles reported displacement and loss of permanent successor, amelogenesis imperfecta, mutation by general absorption, possibility of cancer induction. Recently, it has been reported that leakage by imperfect temporary sealing when FC-soaked cotton was inserted into the root canal caused necrosis of surrounding tissues. and that necrosis of alveolar bone related to the use of excessive formocresol. In this case, 2nd primary molar of upper left jaw was treated using formocresol in local clinic, but extracted because of lasting pain. Furthermore, symptoms didn't disappear so patient was refered to us. The patient was 8-year-old male, had foul odor from oral cavity and circular alveolar bone necrosis around the permanent successor' crown. Thus sequestrectomy was operated and observed through 19 months after operation, we found normal root development of permanent successor but no complete regeneration of alveolar bone defect and attached gingiva. Lesion of periodontal tissues by formocresol is irreversible, so we have to confirm the indication in using formocresol and pay attention to complete temporary sealing.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.256-261
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• 2005

Scleroderma is a connective tissue disease of unknown etiology, but known as a kind of auto-immune disease. It is most common in women especially in $30{\sim}50$ years, and very rare in childhood. It can be classified into two main classes : localized scleroderma & systemic sclerosis. Localized type has better prognosis, and usually involves skin only, or in some cases, the muscle below, except inner organs. Systemic type involves skin, oral mucosa and major internal organs. Involving facial skin, we can see small and sharp nose, expressionless stare and narrow oral aperture. Usually they have Raynaud's phenomenon, and in progress, show mouth opening limitation and sclerosis of tongue and gingiva. It is called CREST syndrome showing calcinosis cutis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangioectasia. Treatment of scleroderma is systemic and localized steroid therapy, use of collagen-link inhibitor (D-penicillamine), immune depressor and etc. Mouth opening limitation can be improved by mouth stretching exercise. We report a 6 years old boy, diagnosed with localized scleroderma who had mouth opening limitation. We could get additional mouth opening, and have done successful restorative treatment of mandibular and maxillary 1st and 2nd deciduous molar under deep sedation with nitrous oxide and enflurane.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.1
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• pp.66-72
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• 2012

Autogenous tooth transplantation can be defined as the surgical movement of a tooth from one position in the mouth to another in the same individual. The most common reasons for tooth transplantation include replacement of a missing first molar, transplantation of impacted canines to their normal positions in the arch, and transplantation of premolars in areas of missing teeth, especially in the anterior area of the mouth. The key to successful tooth transplantation is proper selection of graft with adequate root development as well as the design of surgical operation. Root development stage with half to three-quarter-developed roots increase the success rate of autotransplantation. We report the cases of successful autotransplantation which resulted in ideal healing of periodontal ligament, gingiva and alveolar bone. All transplanted teeth presented immature root formation at the moment of the procedure. After surgical procedure, we can observe good healing pattern without endodontic problem.