This study tried to focus on nontraditional job that has not been studied in terms of the subjects associated with MSDs(Musculoskeletal Disorders). Specifically, dental procedure was the job to be analyzed in this study. An alternative method as well as a traditional method for viewing teeth while performing simulated dental procedures. Four graduated students did both methods(direct view and indirect view) as the subjects in this study. The method based on indirect view used a video camera and monitor to view the teeth. The experiment was conducted five times for each subject. The major findings in this study were as follows; 1) Job speed was increased with the repetitions for both methods, 2) Difference of Neck flexion between direct and indirect methods was statistically siginificant(Neck flexion for indirect method was dramatically decreased), 3) Difference of job speed between direct and indirect methods was statistically significant(Job speed for direct method was faster than that of indirect method), 4) Difference of error rate between direct and indirect methods was statistically significant(error rate for direct method was lower than that of indirect method), 5) Even though indirect method did not provide better performance in terms of job speed and error rate yet, it seemed to need a trade-off between two methods in the future since indirect method provided better working postures than that of direct method.

The purpose of this study was to observe the histopathologic reaction in vital bone to various surface treated implants. For this purpose, ten New Zealand Albino rabbits, weighing 3.3 to 4kg were used as experimental animals. All the experimental groups divided into five groups; 1) Machined surface as control, 2) RBM(resorbable blast media), 3) RBM etched nitric acid solution, 4) RBM etched sodium hydroxide solution, 5) RBM etched acid, alkali, and heat treated group on each. All the surfaces of implants were examined under the scannning electron microscope to distinguish the differences between each experimental groups compare to that on the control group. All the rabbits were implanted into the tibial metaphyses of rabbits. On the 4th and 8th week after implantations, all the experimental rabbits were sacrificed. All the tissues containing each implanted materials were fixed in ethyl alcohol, and embedded in spurr resin as usual manner, sectioned in 10μm or more thickness, grinded, stained with the Villanuevaʼs osteochrome bone stain method and examined histopatholgically. For the fluorescence microscopic examination, three kind of fluorescence dyes, Oxytetracycline, Alizarin-Complexone, and Xylenol-Orange were injected to put into the bone to implant interface produced polychromatic fluorescence labelling on the 1st week, 2nd week, and 5th week on each. On the 8th week after experiments, the animals sacrificed, and the tissues containing the implants were taken, fixed in ethyl alcohol and embedded in spurr resin, sectioned, grounded 10um in thickness and examined under the fluorescence microscope. Following results were obtained; On the scanning electron microscopic examination of the implants, dull cracks, continuous linear indentations were revealed on the machined surface implant, irregular multiple leaflike eruptions on the RBM, and more sharp porous indentation with multiple complicated c rack s on the RBM acid etched surface, and more dull margins on complicated porous indentation on the RBM alkalic etched surface and more dull and less indented particles were noted on the RBM, acid, alkalic etched, heat treated surface, On the histopathologic examination, on the 4th week after experiment, complete osseointegation was noted between the implant and cortical bone on the collar and the apex lesion. and in parts, small newly formed bone spicules directly attached to the screws, and osteoid tissues were revealed in marrow tissues, in all experimental groups. On the histopathologic examination, on the 8th week after experiment, osseointegration is more increased compare to that on the 4th week group, the amount of bone trabeculae and osteoid tissues directly fused to screw of implants were markedly increased. On fluorescence examination, band or linear shape was witnessed on the boarder of compact bone and marrow tissues, and on bone trabeculae according to the formed age. and precipitated as granular and globular shape on the haversian canals. These results indicate that the surface treated method used for the present study render the implants compatible to bone tissue but the tissue compartibility is not different among the surface treated implants.

The purpose of this study was to observe the histopathologic tissue reaction in vital bone in applying the various treated implants. For this purpose, twelve New Zealand Albino rats, weighing 3.3 to 4 kg were used as experimental animals. All the experimental groups divided into four groups; Machined surface as control, RBM(resorbable blast media), Hydroxyapatite-sand and Porous coating groups. All the experimental implants were examined under the scannning electron microscope. All the experimental rabbits were implanted in the tibial metaphyses of rabbits under the general anesthesia with Ketamine HCl(2.5ML /kg.body wt.) injections. For prevention of infection after implant, prophylactic erythromycine injections, 250mg/body wt.(Aldrich Co. USA) were performed on each. On the sixth week after implant, all the experimental rabbits were sacrificed with over dose of Sedaject(Samwoo Pharm .Co. Korea). All the tissues containing each experimental materials were fixed in ethyle alcohol, and embedded in spurr resin(Polytechnic Co. USA) as usual manner. sectioned in 12 um thickness, grinded , stained with the Vulenueva's osteochrome stain methed and examined histopatholgically. For measuring the distances between the implant and bone without any connective tissue interface, all the distances were calculated the length of the implant direct contact to bones. using the view analyzer program( Korea Optical Co.) and the statistical analysis were performed using the one-way ANOVA test. The statistical differences were considered significant below 5% level. Following results were obtained. On the scanning electron microscopic examination, dull cracked continuous linear indentations were revealed on the machined surface implant, irregular sharp indentation on the resorbabale blast, irregular thin exophytic or indentated leaflets on the hydroxyapatite-sand implant, and long ovoid globular particles were revealed on the porous coating implant surface respectively. On the histopathologic examination, complete osseointegation was noted between the implant and cortex bone on the collar and the apex lesion and in parts, small newley formed bone spicules attached to the screws in marrow tissues with compatibility in all experimental groups, but on the aspect of the tissue compatibility to the various implant materials, the superiority of the materials could not identified. The ratio of drect contact between the bone and implant, the HA sand gorup was the most superior among the gorups and followed by the machine surface, but on RBM and porous coating groups were inferior compared to that on the experimental groups. With these results, the superiority of tissue compatibility among the experimental implant group could not be identified

This research was designed to investigate changes of growth factors and bone matrix proteins during the bone healing processes using immunohistochemistry and in situ hybridization. Especially this study was focused on the changes of bone matrix 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 this study are collagen, osteonectin(ON), osteopontin(OPN), osteocalcin(OC). Expression of the proteins were measured using immunohistochemistry. VEGF and ON were measured using in situ hybridization, and northen blot technique. Bone regeneration were observed as early as the third day of experiment. Matrix proteins and growth factors observed around implant were identical to the proteins observed in the control group. The expression of the ON, OC and VEGF were observed mainly in the osteoblast-like cell on the surface of new bone around the implant and the cells lining the margin of bone defect apart from the implant. The observation may not result from direct osteoconducting activities of titanium but by passive adsorption of extracellular factors which has bone inducing capacities. These passive adsorption results in the immobilization of the growth factors and consequent prolongation of the activities.

Since ancient Eygypt, various dental materials were used for lost teeth including gold. The key point of this materials were nontoxic to human body. Since early of 1990's, dental implant was done for recovery of maxillofacial defects. From middle of 1970's, osseointergation concept of implant was introduced and performed in dental field. Biocompatibility of titanium showed good effect for osseointergration but had some problems (Galvance current and toxic corrosion) with suprastructures such as gold crowns. This study was performed to make safe dental implants which have reduced Galvanic currents and corrosion. 3 kind of dental casting gold alloys (different Gold contents, 1㎝×1㎝×0.1㎝ plates.) were used as experimental group, while Titanium were used as control group. Normal human osteoblasts(NHOsts)were cultured during 1-4weeks for histologic study. For analysing the calcium(Ca), Phosphorus(P) and alkaline phosphatase(ALP), NHosts were cultred during 2-23days. After experiments, histologic finding were observed by LSM and SEM. Ca, P, ALP concentration by automatic biochemical analyzer were analyzed by ANOVA test and linear regression method. The results were as follows. Biocompatibility of dental casting gold alloys were similar to titianium alloys histolgically. Biochemical analysis of dental casting gold alloys had no significant difference to titianium alloy except AIGIS-Fine. We could conclude that biocompatibility of dental casting gold alloys with high contents of gold were superior to that of low contents and alloys with high contents of gold had no significant difference from titanium on NHost culture. Gold dental implant might be better than titanium implant due to similar biocompatibility and no galvanic currency.

1'hi s s t u dy was pe rformed to investigate the osseointegration on the interface between bone and dental casting gold alloy's impla nts . Some inves tigators prese nted that only fi brous integratioJ1 in implant interface of precious met al im plants was occu red. 1'he mate ri a ls of dental implant must have biocompatibility and have no phY5ical 01' chemical s ide effect lmpla nts whi ch we re made of pure t itanium or titanium alloys had 50me chemical problem such as Galvanic current wi th s uprastru ctu re cur re ntly. So. we t hought that there was no problem if dental casting gold al1 0y’s impla nts had 5ucceed osseoin tegration. Thi s s tudy used 99%. 86%. 70% gold composition ìmplant as experimental group and tita niuITI implant as cont ral g rOllp. After 4th a nd 8th weeks of implant impLantation. experimental animals were saC l 나 i ce d and hi stologic sections we re made. All sections were examined by 8EM. PM. L8M. and EPMA. lmplants made of dental casting gold a ll oys occllrred good osseointegration as titanium implants. Osseointegr ation were not depend on the gold composit ion in implant groups ’ denta l casting gold al1oys. Both groll ps‘ osseointegration were 1TI0re completed in 8th weeks than 4th weeks . From t he a boving results. dental casting gold alloy's implants had induced similar osseointegrat ion to t h at 01" titan iu rn irnplants . So if we make implant and suprastructllre of dental casting gold alloys. Galvanic current and chemical co rrosio ns wOllld be sllppressed

The ciga rette smoki ng may act direct ly on the oral mucosal membrane The effects of smoking has many harrnJul effects on the oral cavi ty ‘ s uch as oral cancer. oral Icukoplakia , erythroplakia‘ nicotine stomati tis. ha iry tongue. smoker’s melanosis. acute nec roti zing ulverative gingivitis, gingivitis/periodontitis ‘ treatment of periodontitis. implant surgery a nd den tal cari es. lf pregna nt woman smokes. the tobacco can effect on the both pregnant and embryo/fetus negati ve ly. For the cessation 0 [' smoki ng, the dentists have an important role to play in preve nti ng t he harmful efTects on smoking in the oral cav ity, Conseq uently smoking cou nseling should be as a part of the dentist's job in the de ntal pract ice,

본 연구는 연역조직 회학 방법 및 in situ hybridization 법을 이용하여 골 치유 과정중의 골성 장 반응 빛 골 기질 단백질 형성이| 관여하는 여러 성장인자 및 골기질 관련물질에 대한 변화를 알아보고자 하였으며 특히 임 플란트 배식 후 티티늄 표연과 인접한 주변 골에서 나타나는 다양한 골기질 단백질의 형성과 골 성장과 관련한 성장인지들의 변화를 관칠하고자 히였디 직경 3 -5mm의 thread - ed implan t를 백서 장골에 매 식한 후 시 간적 변화에 따른 골기질 관련 물질 및 관련 mRNA의 분포변호}를 관찰히였다 디1 상은 콜리 겐 . osteonectin(ON). osteopontin(OPN). osteocalcin (OC) 동의 분포의 변호}를 연역조직화학적 방법으로 보고 이와 힘께 골기질 형 성관련 성장인자인 VEGF와 ON 의 l알헌을 in situ hybricli za tion 법을 이용해서 관찰하였다 3일째 소견에서 는 골 내부에 형성된 나사 산과 잉프란트의 강제적인 접 촉으로 인해서 높은 접촉률을 나티내고 있었으나‘ 부위에 따라서는 혈벙으로민 둘러씨인 부분도 관칠되었 다 7일째 소견에서 는 이 같은 인위적인 접촉부위에서 골 흡수가 일어니연서 골접촉이 크게 감소하였다 7 일과 14일에서 골의 형성은 이주 낮은 정도로 나타났으마. 14 일째에 는 골 집촉의 증기기 다소 나타나지만 골 밀도는 골의 게조로 인해 김소하는 소견을 나타내 었 다 연역조직화학적 염색에서 대조균은 콜라겐이 결합조직 에 서 항상 강한 양성 반응을 보였다 반면 실험군에서는 신생 골에서 일부에 서만 약한 양성 반응을 보였다 OC은 신생골에서는 거의 관찰되지 않았으며 기존 골의 손상부위에 부분적으로 양성 만응을 보였다 OPN은 결함조직 에서 강한 양성 반응을 보였으며 신생 골의 골양 조직과 골소공 주변에서 양성반응을 나타내었다 ON은 기존골의 일 부와 신생골에서 관찰 되었다 특히 골모세포와 골세포에서 양성반응을 나타내 었다 대조군과 실험군들 간의 연역조직화학적 염색에서 의 뚜렷한 차이는 보이지 않았다 OC은 대조군에서와 마찬가지로 신생골에서는 거의 관찰되지 않았으며. 인접 골 주변부에서 부분적 으로 양성 반응을 보였다 OPN은 대 조군과 실험군 동일하게 결합조직 에서 강한 양성 반응을 보였으며 신생골의 골양 조직과 골소공 주변에서 발현되는 것도 유시하였다 ON의 말현 OJ상도 대조군의 경우와 통일하였으며 골모세포나 골세포 에서 양성 반응을 나티 내 띤 서 골질에 대해서 는 신생골이니 골 게 조 후의 골보다 석회화가 어느 정도 진행된 골 개조 이전의 골에서 뚜렷한 양성을 보였다 ON 의 발현잉상에서 연띄조직화학 염색소견과 달러 골기질 단백질의 형성과정에서 나타나는 세포내 mRNA의 발현은 임플란트에 보다 근 접힌 세포에서 발현이 증가히는 깃이 관찰되었다 이상의 결과에서 얻은 겔론은 다음과 같다 i 소형 임플린트의 떼식 시 나타나는 조직 띤응은 정싱크기 의 임 풀란트에서외 동일힌 소견을 나타내았다 2 골재생은 3일 째부터 관칠되었으며 14 일이후 골재소가 나티니 21 일까지 지속되었다 3 임플란트 주맨에서 나타냐는 골재생관련 성장인자외 골기질 단백질은 골결손으로 인한 재생 시와 동일한 소 낀을 니 타내 었다 4 띤약조직화흐l 염색소견과 달리 골기질 단백질의 형성과정에서 나타나는 세 포내 mR NA의 발현은 임플란트에 보디근접한 세포에서 발힌이 증가히는 것이 관찰되었으며 이는 임풀란트 제 료의 표면이 골형성 유도능을 가진 것이기 보다는 골형성 유도 능을 가진 세 포외 인지들이 티타늄 표띤 애 수동적으로 홉착됨으로 잔존 기간이 증가하고 이동성이 감소함으로서 나타나는 현상으로 보인다 5. 티타늄 인 플렌트의 표띤은 특띨힌 처리 없이 도 곧형성 유도른 증가시 키는 것으로 보인다

The aim of this study was to investigate the cytotoxicity of dental casting gold alloys. Recently, "biocompatability" is considered the most important requirement of dental materials. Dental metals and alloys were estimated by quantity of released ions, which had influenced to living tissues. The requirement of using normal human cells for cytoxicity strudy were abruptly increased. We used the cultured normal human gingival fibroblasts to estimate the cytotoxicity of dental casting gold alloys. The product of S company(Korea, AIGIS-SOFT, AIGIS-PLUS, AIGIS-A, AIGIS-PT, experimental group) and D company's (German, Biocclus inlay, Biolor SG, Stabilor NF Ⅳ, Degulor B, control group) dental casting gold alloys were used. The morphological investigation, hemolysis test, MTT assay and SRB assay were done in vitro. In vivo, inflammatory reaction in rat was examined for 2 weeks. 1. In the result of cytotoxicity assay, there were some differences but was no significancy among the results between two group's hemolysis, MTT and SRB assay. 2. The gingival fibroblasts attached to the surface of dental casting gold alloy showed various features and increased in number as the time had passed. 3. In vivo, chronic inflammatory cell infiltration was prominent from 3 days to 1 week and inflammation was reduced as time had gone. From the aboving results, there were no significant differences in cytoxicity depending on the ratio of gold content, but showed differences depending on the ratio of total precious and non-precious metal content between two groups. In vitro study showed few differences in inflamation reaction.

This expe띠nent was performed to evaluate the contamination of private dental clinics and the effect of antiseptics. 까lere are high risks of cross infection in dental clinic during the dental treatffient both in dental clinic workers and dental pa디ents. We took the samples in 30 dental clinics. 4 sites(hand piece, head rest, room air, and cuspidor) were sampled in each clinic. Each samples were studied with molecular biologically using DNA sequencing. After DNA sequencing, all microorganisms were tested with 4 commercial antiseptics. The results were as followings. 1. 30 species and 54 strains of pathogenic microorga띠sms were found in 30 dental cωúcs. 2. 깨ere were no signifìcant difference in regions for fmding the micr，∞rganisms(p(O. 06). 3. 8 species and 13 sσains of micr∞rganisms were found in room air of Seoul area, and 6 species and 10 strains were in head rest of An-yang area were the most frequent sites. 4. Staphylococcus epidermidis was found the most frequently. 5. Calymatobacterium granulomatis and Enterococcus faecalis were found, which were not concemed with oral disease 6. Sterilization effect showed difference by antiseptics and also showed difference by sterilization method and sites. From the aboving resutls, there were no significant difference in regions for finding microorganisms, but little differences in sampling site. There were quite differences depend on the sterilization method and antiseptic drugs. It may be exist that there are high risks of cross contamination between dental c뼈c workers and patient.