Most Authors reported that mouth guard is a part of equipment for body-contact sports players. Mouth guards protectorofacial injuries but have some problems in breathing and speaking. Some authors reported that mouth guards have alsoimprove the muscle strength and sport ability. This experiment was performed to study the change of masseter muscle EMGafter wearing of mouth guard. 10 D university male base ball players were participated in this study. After impression taking,mouth guards were constructed and weared. Masseter muscle EMG and nasal ventilation after ten day's adaptation werechecked. They were requested clenching with or without mouth guard. EMG and nasal ventilation were checked by iworx 104instrument simultaneousley. The result showed that masseteric EMG were improved and nasal ventilation were stable afterwearing mouth guard. It concluded that mouth guard had improved muscle activity and stabilized the nasal ventilation dependon experimental method.

This research was designed to investigate changes of growth factors and bone matrix proteins during the bone healingprocesses using immunohistochemistry and in situ hybridization. Especially this study was focused on the changes of bonematrix and growth factors around the titanium implant. Threaded implants were introduced into the long bone of tibia.Time dependent changes of several bone associated protein and and its mRNAs were observed. Proteins investigated in thisstudy are collagen, osteonectin(ON), osteopontin(OPN), osteocalcin(OC). Expression of the proteins were measured usingimmunohistochemistry. VEGF and ON were measured using in situ hybridization, and northen blot technique. Bone regenerationwere observed as early as the third day of experiment. Matrix proteins and growth factors observed around implantwere identical to the proteins observed in the control group. The expression of the ON, OC and VEGF were observedmainly in the osteoblast-like cell on the surface of new bone around the implant and the cells lining the margin of bone defectapart from the implant. The observation may not result from direct osteoconducting activities of titanium but by passiveadsorption of extracellular factors which has bone inducing capacities. These passive adsorption results in the immobilizationof the growth factors and consequent prolongation of the activities.

ISPARC (Secreted protein acidic and rich in cysteine) is detected in the bone stroma during wound-healing process. Tounderstand the roles of SPARC in bony wound-healing process, SPARC cDNA were synthesized from rat calvarial osteoblastculture, and SPARC protein was synthesized from the cDNA. To observe the effects of SPARC protein on the differentiationof osteoblasts, bony defect were made on rat tibia, and the distributions of bone matrix related proteins and SPARC wereinvestigated using immunohistochemistry. In the rat osteoblastic culture using untreated plastic surface, Collagen-SPARCtreated surface presented higher protein synthesis than untreated surface or only collagen treated surface. SPARC synthesisin the bony defect of rat tibia was augmented by introducing SPARC to the bony defect. SPARC synthesis were increasedfrom the center of the defect compared to the control. SPARC synthesis in cells of the center of the defect was increased andmaintained for 14 days. We could conclude that SPARC introduction may affect the early bone matrix formation, includingSPARC, and mineralization in bony wound healing process.

An extremely rare case of chondromyxoid fibroma of the zygomatic arch in a 65-year-old woman is presented. Block resectionand immediate reconstruction were done with calvarial bone with fixed with microplate and screws through the hemicoronalapproach. Follow-up studies have shown no tumor recurrence for 7 years. Also, we carried out an immunohistochemicalstudy. The results showed positive S-100 and vimentin staining, while showing only very weak stainingfor NSE. The Ki-67 staining study showed a PI-index of only 0.67%.

Adenoid cystic carcinoma(ACC) is one of the most common malignant tumors of minor salivary glands and can also arise ina variety of sites in the head and neck including the major salivary glands, the esophagus, the lacrimal glands. ACC showsslow but relentless growth, so it shows long-term recurrence. The various reports about prognostic factors which influencethe recurrence pattern are introduced but the reports about prognostic factors are rare in Korean adenoid cystic carcinomapatients. We examined 40 ACC patients who finally diagnosed at Department of Oral Pathology, Seoul National UniversityDental Hospital. Clinicopathologic and immunohistochemical features were reviewed and factors correlated with recurrenceand survival were analyzed. The 5-year survival rate of T3,T4 stage was 31.2%, while that of the T1,T2 stage was 88.2%,and the difference 5-year survival and T stage was statistically significant. The rate of local recurrence was 20% and therate of distant metastasis was 27.5%. Mean recurrence time were 4.8 years and 5.2 years. There was no significant differencebetween age, sex, T stage, TNM stage, histologic type and recurrence. But the high T stage and the solid type recurredmore frequently. There was no significant difference between recurrence rate, 5-year survival rate and Ki-67, MVDexpression. But the higher expression of Ki-67, MVD show the higher recurrence rate and the lower 5-year survival rate.

System L amino acid transporter is a major route for providing living cells with neutral amino acids including several essentialamino acids. To elucidate the expression pattern of L-type amino acid transporter 1 (LAT1) in the bone formationprocess, the expressions of LAT1 and its subunit 4F2 heavy chain (4F2hc) were investigated in the healing process after theimplantation of bone graft materials in the calvarial osseous defected rats. Circular calvarial defects (1 cm in diameter) weremade midparietally. The rats were divided into 4 groups of 1 control group and 3 experimental groups. In the control group,the defect was only covered with soft tissue flap. In the experimental groups, they were filled with human particulate dentin(particulate dentin group), with plaster of Paris (plaster of Paris group) and with the mixture of human particulate dentinand plaster of Paris with ratio of 2 : 1 by weight (mixture group). The rats were sacrificed at the 1, 2, 4 and 8 weeks afteroperation and the RT-PCR analysis and immunohistochemical analysis were performed. In the RT-PCR analysis, the mRNAsof LAT1 and 4F2hc were strongly detected in all 4 groups. In the immunohistochemical analysis, at 1 week after operation,the LAT1 protein and its subunit 4F2hc protein were mainly expressed in the osteoblasts, osteocytes and interstitial tissuesof the around the defect and inner part of newly forming bone in all 4 groups. The expressions of LAT1 and 4F2hc proteinswere decreased at 2 and 4 weeks after operation. The LAT1 and 4F2hc proteins were scarcely expressed at 8 weeks after operationin all 4 groups.These results suggest that the LAT1 and its subunit 4F2hc highly expressed at the early stage of new bone formation andmay have an important role in providing cells with neutral amino acids including several essential amino acids at that stage.

It is well known that the imbalance between epithelial cell growth and inhibitor factors may cause human epithelialcancer. Over-expression of the epidermal growth factor receptor(EGFR) has been implicated in the development of oral squamouscell carcinoma. ZD1839 inhibits selectively the EGFR tyrosine kinase activity and is clinically used for cancerpatients. However the mechanisms by which it exerts its anti-tumor activity remains unclear. This study attempted to determinethe mechanisms underlying the effects of ZD1839 on the cellular level and to characterize the effects of ZD1839 withregard to human oral squamous cell carcinoma(OSCC) cell growth. The YD-10B and YD-38 cell lines established from OSCCin the department of Oral Pathology, Yonsei University College of Dentistry and ZD1839(Iressa) were used for this study. Theinhibition of cell proliferation induced by ZD1839 was reversible and the lowest dose of ZD1839 that produced statisticallysignificant growth inhibition in YD cell lines were 0.1 μM. The delay in cell cycle progression was induced by 0.1 μM ofZD1839 treatment after 24 hr. This reduction in cell proliferation and cell cycle delay were associated with up-regulation ofthe cyclin dependent kinase inhibitor(CDKI), P21CIP1/WAF1 and P27KIP1. Reduced expression of cyclin D1 was also observed aftertreatment with ZD 1839 to YD-38 cells but not to YD-38. The present results suggest that the antiproliferative effects ofZD1839, in vitro was associated with degradation of cyclin D1, which may be used as a possible indicator of a high cell sensitivityto ZD1839.

This experiment was performed to study the biocompatibility of xenograft materials (ABBM. coralline HA). Both autogenousbone grafts and allogenic banked bone were frequently and successfully used to promote regeneration of parts ofskeleton. The use of these types of grafts were limited by the cost of donor site operation for autogenous boneor by fear ofthe risk of infection of allogenic materials. Another type of graft is xenograft which include ABBM and coralline HA. For investigatingthe biocompatibility, generally many investigators used cancer cell lines or animal cell lines. But cancer cell linesand animal cell lines had functioned different metabolism from normal human cell. So the experiment used normal humanosteoblast for compare the biocompatibility of ABBM with coralline HA which were fixed in 24 well base contained culturemedium. After 1st, 3rd, 7th, 14th, 28th days, the culture medium were taken out and checked the concentrations ofcalcium(Ca), inorganic phosphate(IP) and alkaline phosphatase(ALP). In another method, histologic samples were investigatedafter 8weeks of xenograft materials implantated on rabbit's tibia, the bone was cut and made undecalcified ground samplesand checked with fluorecent microscope, polarizing microscope, reflection electron microscope and electron probemicroanalysis. The statistical results of concentrations (Ca, IP, ALP) of materials in the culture medium have decreasedbyday's, which meant that xenograft materials were effective for bone remodelling. The concentrations in the culture mediumof ABBM were lower than that of coralline HA, that meant that biocompatibility of ABBM were superior than that of corallineHA. Histologic samples showed that ABBM had better bone remodelling effect than coralline HA. ABBM showed good alizarinred marking lines, more deposition of Ca, IP, and dense color of bone around newly formed osteon and bonetrabeculae. it was concluded that ABBM was more biocompatible than corallineHA in vivo and in vitro test.

It has been reported that light-emitting diodes(LED) can be used in the treatment of oral diseases. Although bio-stimulatoryeffects of LED irradiation such as promotion of wound healing have been well known, there are few reports aboutmolecular mechanisms associated with wound healing by LED irradiation. The purpose of the present study was to investigatethe expression pattern of various extracellular matrix(ECM) molecules in relation to wound healing after LED irradiationon primary human gingival fibroblasts(hGFs) in vitro. The source of light for irradiation was a continuous-wave LEDemitting at a wavelength of 635 nm, and manufactured that energy density was 5 mW/cm2 on sample surfaces. The hGFswere irradiated for 1 hour at 37℃ in 5% CO2 humidified chamber. Experimental samples were acquired at 0 (right after irradiation),24 and 48 hour after irradiation. To investigate the molecular mechanisms associated with wound healing, we examinedthe mRNA expression of 6 types of collagens, 7 types of matrix metalloproteinases(MMPs) and 4 types of tissue inhibitionof metalloproteinases(TIMPs) after LED irradiation by RT-PCR. The mRNA expression of collagen 4, MMP-3, 9, and16, and TIMP-3 was influenced by LED irradiation. Generally, the collagen expression of the irradiation group was slightlyincreased, particularly collagen 4 was significantly increased at 0 hour. The expression of MMP-3 was increased at 0 and 24hours and MMP-16 was increased at 24 hours, respectively. The expression of MMP-9 was decreased at 0 hour and increasedat 24 and 48 hours. The mRNA expression of TIMP-3 was significantly decreased at 24 and 48 hours after irradiation. Theseresults suggest that the altered expression of ECM molecules after LED irradiation may contribute to the accelerated woundhealing.

β-catenin is a cytoplasmic protein that participates in the assembly of cell-cell adherens junctions by binding cadherinsto the cytoskeleton. In addition, it is a key component of the Wnt signaling pathway. Activation of this pathway triggers theaccumulation of β-catenin in the nucleus, where it activates the transcription of target genes. Abnarmal accumulation of β-catenin is characteristic of polyposis coli(APC) or Axin tumor suppressor proteins, which regulates β-catenin degradation,or activating mutations in β-catenin molecule itself. Here we show that overexpression of Sox4 down-regulates wild typeβ-catenin in HEK 293 cells. The inhibitory effect of Sox4 on wild type β-catenin is apparently mediated by the ubiquitin-proteasoem system and requires an active glycogen synthase kinase 3β(GSK3β). Mutations in the N-terminus of β-catenin(S33Y) which compromise its degradation by the proteasomes or inhibition of GSK3β activity rendered β-cateninresistant to down-regulation by Sox4. In light of recent evidence that Sox4 expression is activated in colon and other tumorswith β-catenin dysregulation, our findings suggest that Sox4 is part of a feedback inhibitory pathway for Wnt signalingin normal cells. Moreover, the mutations in APC, Axin or β-catenin in cancer cells appear to render β-catenin resistantto the effects of Sox4 inhibition.

Pro-inflammatory cytokines are important mediators of cutaneous cellular activities during many oral mucosal diseases.IHOK culture model transfected by E6/E7 genes provide further evidence for the role of HPV in tumorogenesis. It is interestingto investigate cytokine expression of immortalized human oral keratinocyte(IHOK). The purpose of this study were toanalysis cytokine mRNA expression levels of NHOK and IHOK by RT-PCR. IHOK showed about 5 fold increases of IL-6 comparedwith NHOK, while TNF-α was the lowest. It suggested that immortalization of NHOK with E6/E7 could result in elevatedexpression of IL-6, and IHOK be in the intermediate stage of oral carcinogenesis.

Epithelium maintains homeostasis by the signaling balance of growth stimulation and inhibition. Recently, loss of growthinhibitory effects of transforming growth factor-β(TGF-β) on epithelial cells is regarded as a possible mechanism ofcancer. Although the genomic mutation in type I and type Ⅱ receptors of TGF-β is considered one of important mechanismof these inactivation, there might be another inactivation mechanism because the mutation rate is relatively low and inhibitoryeffect is not associated with the mutation. The purpose of this study is evaluating controlling mechanism type Ⅱreceptor of TGF-β by detecting effects of TGF-β on growth inhibition and on expression of cell cycle regulatory proteinp21CIP1. Eight cancer cell lines derived from oral squamous cell carcinoma(OSCC) were examined. There was no growth inhibitioneffects by TGF-β except YD-8 cells. YD-8 cells which showed growth inhibition expresses p21CIP1 by TGF-βwhether refractory cell lines, YD-9, did not. All of the tumor cells express mRNA of type Ⅱ receptor by RT-PCR and northernblot analysis, especially on YD-8 and YD-17M. From these results, most of oral cancer cell lines might loose the growthinhibitory effects by TGF-β, and the growth inhibition on YD-8 cells was mediated by expression of p21CIP1.