• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.299-303
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• 2009

Introduction: Maxillary malignant tumors are primary tumors of the maxillary gingiva, sinus, and palate. The purpose of this study was to research the prognosis and treatment modalities of maxillary malignant tumors. Materials & Methods: For this study, 52 patients, who were treated after being diagnosed for maxillary malignant tumors at the department of OMFS at Yonsei University college of Dentistry from January 1997 till April 2008, were classified, then the prognoses of these patients were evaluated depending on their primary site, histopathology and treatment modalities. The results of this study showed that the most common primary site for maxillary malignant tumors was the gingiva and for histopathology, squamous cell carcinoma. Result & Conclusion: The average follow up period was 32.7 months. In determining prognosis, the most important factors were the control of local site and metastasis of cervical lymph nodes. Therefore, for a better prognosis, a tumor free margin during surgery and a periodic follow up to examine for metastasis to cervical lymph nodes and other organs are necessary.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.335-339
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• 2009

The purpose of this study was to evaluate clinical and radiographic changes of regular diameter implants placed in the posterior region. A total of 47 standard diameter implants were consecutively placed in the posterior region of 20 partially edentulous patients. The diameters of the implants were 4.1mm (N=35, 74%) and 4.3mm (N=12, 26%), respectively. Peri-implant bone loss and clinical parameters such as mobility, suppuration, swelling, bleeding on probing (BOP) were evaluated at the baseline and?the final follow-up visit. The age of the patients ranged between 24~82 years (mean age: 54.7 years). The cumulative survival rate of the regular diameter implants loaded for a period of 3-24 months (Mean: $11.7{\pm}7.9$ month) was 100%. The average bone loss over the follow-up was $0.36{\pm}0.67\;mm$. Success rate was 95.7%. Only two implants failed (bone loss exceeding 1mm after 1 year of placement). Some prosthetic complications occurred, such as screw loosening (N=1) and dissolution of cementation material (N=2). The present study describes successful outcome following the use of standard-diameter-implants placed in the posterior region, and further comprehensive maintenance practices and follow-up schedules are required.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.329-334
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• 2009

Objective: To evaluate the ratio between bone-contact length and inter-segmental length of the rigid fixation screw used in bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. Material and Methods: Records of 40 patients with Class III malocclusion were selected. 20 of them had BSSRO, while the other 20 had BSSRO with maxillary LeFort I osteotomy. All of the patients had three noncompressive bicortical screws inserted at the gonial angle through transcutaneous approach. Two screws were inserted antero-posteriorly above inferior alveolar nerve and one screw was inserted below. The lengths of bone-contact and that of inter-segmental part were measured using cone-beam computed tomography. Ratio between these two measured lengths was calculated. Results: Both bone-contact and inter-segmental lengths were longer in BSSRO group than in BSSRO with maxillary LeFort I osteotomy group. Ratio of bone-contact to inter-segmental length was lower in BSSRO group than in BSSRO with Lefort I group. Both bone-contact and inter-segmental lengths were longer at the antero-superior position than at the inferior position. However, their ratio showed little difference. Conclusion: This study suggest that stability of screws in BSSRO group was greater than in BSSRO with Lefort I group. Stability of screws at the antero-superior position was greater than at the inferior position. Ratio of bone-contact to inter-segmental lengths was 0.2 in average.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.312-315
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• 2009

Objective: It is important to sterilize oral cavity with antibacterial agent before surgery for preventing infection. The object of this study was to compare the effect on reduction of salivary bacterial counts according to applied time when povidone-iodine (PVI) and chlorhexidine gluconate (CHX), most broadly used materials in dentistry, were applied intraorally before the surgery. Methods: Sixty subjects were divided into 6 groups. PVI and CHX were applied in each group for 1, 2 and 3 minutes, respectively. Then salivary microbacteria taken before and after applying the materials were cultured using 5% sheep blood agar plate. Results: There was significant difference in reduction of microbacteria in both PVI and CHX and the effect did not show differences depending on time. When applied for a minute, PVI showed somewhat higher reduction rate than CHX, but in the other groups, there was no difference in reduction rate. Conclusion: We found that there was no significant difference in sterilization ability of PVI and CHX in all groups in this study. Therefore, both agents would get sufficient effect when applied for a minute.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.287-293
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• 2009

Cell survival is the result of a balance between programmed cell death and cellular proliferation. Cell membrane receptors and their associated signal transducing proteins control these processes. Of the numerous receptors and signaling proteins, epidermal growth factor receptor (EGFR) is one of the most important receptors involved in signaling pathways implicated in the proliferation and survival of cancer cells. EGFR is often highly expressed in human tumors including oral squamous cell carcinomas, and there is increasing evidence that high expression of EGFR is correlated with poor clinical outcome of common human cancers. Therefore, we examined the antiproliferative activity of gefitinib, epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI), in head and neck cancer cell lines. SCC-9, KB cells were cultured and growth inhibition activity of gefitinib was measured with MTT assay. To study influence of gefitinib in cell cycle, we performed cell cycle analysis with flow cytometry. Western blot was done to elucidate the expression of EGFR in cell lines and phosphorylation of EGFR and downstream kinase protein, Erk and Akt. Significant growth inhibition was observed in SCC-9 cells in contrast with KB cells. Also, flow cytometric analysis showed G1 phase arrest only in SCC-9 cells. In Western blot analysis for investigation of EGFR expression and downstream molecule phosphorylation, gefitinib suppressed phosphorylation of EGFR and downstream protein kinase Erk, Akt in SCC-9. However, in EGFR positive KB cells, weak expression of active form of Erk and Akt and no inhibitory activity of phosphorylation in Erk and Akt was observed. The antiproliferative activity of gefitinib was not correlated with EGFR expression and some possibility of phosphorylation of Erk and Akt as a predictive factor of gefitinib response was emerged. Further investigations on more reliable predictive factor indicating gefitinib response are awaited to be useful gefitinib treatment in head and neck cancer patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권1호
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• pp.1-6
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• 2009

DNA double-strand breaks (DSBs) occur commonly in the all living and in cycling cells. They constitute one of the most severe form of DNA damage, because they affect both strand of DNA. DSBs result in cell death or a genetic alterations including deletion, loss of heterozygosity, translocation, and chromosome loss. DSBs arise from endogenous sources like metabolic products and reactive oxygen, and also exogenous factors like ionizing radiation. Defective DNA DSBs can lead to toxicity and large scale sequence rearrangement that can cause cancer and promote premature aging. There are two major pathways for their repair: homologous recombination(HR) and non-homologous end-joining(NHEJ). The HR pathway is a known "error-free" repair mechanism, in which a homologous sister chromatid serves as a template. NHEJ, on the other hand, is a "error-prone" pathway, in which the two termini of the broken DNA molecule are used to form compatible ends that are directly ligated. This review aims to provide a fundamental understanding of how HR and NHEJ pathways operate, cause genome instability, and what kind of genes during the pathways are associated with head and neck cancer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권1호
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• pp.7-12
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• 2009

Purpose: Gelatin-hydroxyapatite nanocomposite is similar to inorganic nanostructure of bone. To make a scaffold with osteoinductivity, bone marrow derived stem cells from rabbit femur were impinged into the nanocomposite. This vitro study was to test osteogenic differentiation of the stem cells in the nanocomposite, which was made by authors. Material & Methods: Gel-HA nanocomposite with 10g of HA, 3 g of Gel has been made by co-precipitation process. Bone marrow was obtained from femur of New Zealand White rabbits and osteogenic differentiation was induced by culturing of the BMSCs in an osteogenic medium. The BMSCs were seeded into the Gel-HA nanocomposite scaffold using a stirring seeding method. The scaffolds with the cells were examined by scanning electron microscopy (SEM), colorimetry assay, biochemical assay with alkaline phosphatase (ALP) diagnostic kit, osteocalcin ELISA kit. Results: Gel-HA nanocomposite scaffolds were fabricated with relatively homogenous microscale pores ($20-40{\mu}m$). The BMSCs were obtained from bone marrow of rabbit femurs and confirmed with flow cytometry, Alizarin red staining. Attachment and proliferation of BMSCs in Gel-HA nanocomposite scaffold could be identified by SEM, ALP activity and osteocalcin content of BMSCs. Conclusion: The Gel-HA nanocomposite scaffold with micropores could be fabricated and could support BMSCs seeding, osteogenic differentiation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권5호
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• pp.346-352
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• 2009

There have been reports of successful bone formation with sinus floor elevation by simply elevating the maxillary sinus membrane and filling the sinus cavity below the lifted sinus membrane with a blood clot. But, in a review of the current literature, we found no animal study that substantiated blood clot's ability in this respect. The aim of this study was to investigate the effect of the method of maxillary sinus floor augmentation using the patient's own venous blood in conjunction with a sinus membrane elevation procedure. An implant was placed bilaterally in the maxillary sinus of six adult mongrel dogs so that it protruded 8 mm into the maxillary sinus after sinus membrane elevation. On one side of the maxillary sinus, the resultant space between the membrane and the sinus floor was filled with autologous venous blood retrieved from the dog. On the opposite side, the maxillary sinus was left untreated as a control. The implants were left in place for six months. The mean height of the newly formed bone in the sinus was 3.7 mm on the side without venous blood and 3.5 mm on the side with venous blood (p>0.05). There was no difference between the two sides regarding new bone height in the sinus. Our results indicate that filling the space between the lifted sinus membrane and the sinus floor with venous blood has no effect on bone formation around implants placed in the maxillary sinus cavity.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권1호
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• pp.21-25
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• 2009

Objective: The purpose of this study is to determine the prevalence of sinus disease and abnormalities in patients scheduled for dental implant in maxillary posterior area using cone beam CT. Patients and Method: One hundred five maxillary sinuses in eighty-seven patients who underwent cone beam CT for dental implant in maxillary posterior area were included. Any patients who had previous history of sinus operations were not included. The sinus abnormalities were classified as follows ; normal (membrane thickness <2 mm), mucosal thickening (membrane thickness ${\geq}$ 2 mm and < 6 mm), partial opacification (membrane thickness > 6 mm but not full), full opacification and mucous retention cyst. The relationship between the remaining bone height, sinus symptoms and maxillary sinus abnormality was statistically surveyed. Results: Of 105 maxillary sinuses in 87 patients, 80 (76%) maxillary sinuses showed abnormalities ; 4 of 4 symptomatic patients and 76 of 101 asymptomatic patients. Mucosal thickening was the most common sinus abnormality. Only 3 (4%) of 80 maxillary sinus abnormalities were caused by the odontogenic origin. The prevalence of maxillary sinus abnormalities was higher in the symptomatic group than asymptomatic one (p<0.05). Conclusion: Maxillary sinus abnormalities were very common in the patients who were planning implantation in maxillary posterior areas. This result supports that thorough evaluation for maxillary sinus is recommended when implant treatment is planned for those areas.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제35권1호
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• pp.31-34
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• 2009

Purpose: This study compared the frequency of postoperative infections in patients for a closed mandibular fracture with that without the postoperative antibiotic prophylaxis. Patients and Methods: 48 patients without any specific medical history were divided into two groups depending on whether or not antibiotics had been applied after the surgery. The 24 patients in group 1 received only a second-generation cephalosporin ($Cefotetan^{(R)}$) intravenously from admission to immediate after the surgery. Likewise, 24 patients in group 2 received 1.0g of $Cefotetan^{(R)}$ twice daily longer than the third day after surgery. The mean (SD) duration of antibiotics administration after surgery was 6.9 (${\pm}3.56$). The patients were evaluated after surgery for any postoperative infections according to the criteria: purulent drainage from a wound, spontaneous wound dehiscence accompanied by swelling, pain, and fever around the wound. Results: Postoperative infections were encountered in 2 out of 24 patients in group 1, who received antibiotic medication until shortly after surgery, and in 3 out of the 24 patients in group 2, in whom the medication was continued even after the surgery. There was no sig nificant difference in the incidence of postoperative infections between the two groups. Conclusion: From this study, postoperative use of antibiotics seems to be unnecessary with view of the little significance of the factors that could affect the wound infection.