아르곤 레이저와 가사광선의 복합레진 및 Glass ionomer 중합에 관한 연구

장기택,이상훈,이광수 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.1

Following results were obtained after measuring microhardness value of top and bottom surface of the specimens, which were made of either light curing glass ionomer or composite resin, polymerized with visible light and argon laser varying curing time. 1. In Fuji Ⅱ-LC and Vitremer, significant difference was found in microhardness value, only in less than 10 seconds of curing time between using visible light and argon laser, and in the basis of microhardness value of the bottom surface, curing time of the argon laser takes only a half than that of visible light. 2. In Prisma, significant difference was found in microhardness value, only in less than 20 seconds of curing time between using of visible light and argon laser, and in the basis of microhardness value of the bottom surface, curing time of the argon laser takes only a half than that of visible light. 3. In Z-100, significant difference was found in microhardness value, only in less than 30 seconds of curing time between using of visible light and argon laser, and curing time of the argon laser takes only a quater than that of visible light. 4. In Clearfil, significant difference was found in microhardness value, in every each curing time between using of visible light and argon laser, and curing time of the argon laser takes only a quater than that of visible light.

수종 음료수의 법랑질과 상아질 침식에 관한 연구

장기택 大韓小兒齒科學會 1997 大韓小兒齒科學會誌 Vol.24 No.4

The aim of this study was to evaluate the in vitro effects of exposure to acidic beverages on microhardness of enamel and dentin. Thirty enamel specimens and thirty dentin specimens were obtained from extracted bovine maxillay incisiors. Enamel and dentin specimens were divided into three groups and treated with acidic beverages as follows ; Group 1 : cola(pH 2.52), Group 2 : plain soda water(pH 2.93) and Group 3 : orange juice(pH 3.75). Erosive treatment was performed by storing each specimens for 5 min in 50ml solution of cola, soda water and orange juice. Average microhardness values(VHN) were determined before and after erosive treatment. All beverages produced significant loss of microhardness of enamel and dentin. Microhardness of enamel was reduced in the following order : Group 1 :42.71±4.36(%), Group 2 : 37.09±6.25(%), Group 3 : 35.46±4.98(%). Microhardness of dentin was reduced in the following order : Group 1 : 17.14±3.42(%), Group 2 : 13.89±3.18(%), Group 3 : 13.82±3.50(%). The differences between group 1 and group 2,3 were statistically significant(p<0.05).

가시광선과 아르곤 레이저로 복합레진 중합시 미세누출에 관한 비교 연구

장기택,정태련,김종철 大韓小兒齒科學會 1996 大韓小兒齒科學會誌 Vol.23 No.4

For the purpose of evaluation of microleakage of class V resin restoration, 64 extracted bovine teeth were filled with two kinds of light curing composite resins(Z-100, Clearfil) and polymerized with 40 seconds of visible light and with 10 seconds of argon laser. After 1000 thermocycling(5℃/55℃), specimens were placed in 1% methylen blue dye solution for 72 hours in 37℃ water bath. The specimens were sectioned at center of filling body and the degree of dye penetration was observed with a stereomicroscope. The following results were obtained, 1. Differences of the microleakage of resin restorations polymerized with 10 seconds of argon laser and 40 seconds of visible light were statistically insignificant. 2. There was more microleakage in Z-100 than clearfil and there was a statistical significancy (p<0.05).

중합시간과 중합방법에 따른 자가중합형 상교정용 레진의 중합률의 비교에 관한 연구

장기택,김종철,유종욱 大韓小兒齒科學會 1999 大韓小兒齒科學會誌 Vol.26 No.2

가찰성 상교정 장치에 많이 사용되는 자가중합형 상교정용 레진의 미반응 단량체는 레진의 물성과 생물학적인 면에 많은 영향을 끼친다. 다라서 미반은 단량체를 최소화하고 중합률을 최대로 하는 중합방법에 대한 연구는 중요한 의의를 갖는다. 저자는 자가중합형 상교정용 레진의 중합시간과 중합방법에 따른 중합률을 비교해보기 위해 시편을 다음과 같이 5군으로 나누어 연구를 진행하였다. 상교정용 레진의 분말과 용액을 혼합하여 제 1군은 28℃의 공기중에 보관하였고, 제 2군은 28℃의 물에, 제 3군은 28℃의 물과 30psi의 압력에, 제 4군은 43℃의 물에, 제 5군은 43℃의 물과 30psi 의 압력하에 각각 보관하였고, 10분, 1시간, 12시간, 1일, 3일 경과 후에 각 시편을 Fourier 변환적외선분광법을 이용하여 중합률을 측정하여 다음과 같은 결론을 얻었다. 1. 모든 군에서 중합시간이 경과함에 따라 중합률도 지속적으로 증가하는 양상을 보였다. 10분경과 후의 결과와 비교하여 볼 때, 제 1군은 12시간 경과 후부터 중합률의 증가가 유의성이 있었고, 제 2군과 3군, 4군, 5군은 1시간 경과 후부터 유의성이 있었다.(p<0.05) 2. 10분과 1일, 3일 경과 후에는 제 5군, 제 4군, 제 3군, 제 2군, 제 1군의 순서대로 중합률이 높았다. 3. 중합시 온도에 따른 비교에서, 1일 경과 후를 제외하고는 모든 시간에서 43℃에서 중합시킨 군의 중합률이 28℃에서 중합시킨 군의 중합률보다 유의성 있게 높았다.(p<0.05) 4. 압력은 12시간 경과 후를(p<0.05) 제외하고는 중합률에 영향을 주지 못했다. 5. 보관방법은 1시간 경과 후를(p<0.05) 제외하고는 중합률에 영향을 주지 못했다. Autopolymerized resin facilitates a more rapid and easier means for the construction of removable orthodonic appliances than heat cured resin. But many reports reveal that more unreacted monomer is found in autopolymerized resin. It is very important to achieve maximum degree of polymerization because if polymerization is inadequate, high level of unreacted monomer has been shown to adversely affect mechanical and physical properties, and also the question of allergy or toxicity to methylmethacrylate must be considered. The purpose of this study was to compare the degree of polymerization according to curing method and curing time. Five groups were desinged ; Group 1 was polymerizied at room temperature(28℃) ; Group 2 in 28℃ water ; Group 3 in 28℃ water under 30psi pressure ; Group 4 in 43℃ water ; Group 5 in 43℃ water under 30psi pressure for 10 minutes. 1 hour, 12 hour, 1 day and 3 day. The degree of polymerization was meaured by means of Fourier Transform Infrared spectroscopy. The results were as follows : 1. The degree of polymerization increased constantly in accordance with curing time in all groups and after curing for 10 minutes. Group 1 showed significantly higher degree of polymerization after 12 hours and Group 2, Group 3, Group 4, Group 5 after 1 hour (p<0.05). 2. The degree of polymerization decreased in the order of Group 5, Group 4, Group 3, Group 2, Group 1 except when the curing time was 1 hour and 12 hours(p<0.05). 3. The degree of polymerization Group 4, Group 5 cured at 43℃ showed significantly higher degree of polymerization than Group 2, Group 3 at 28℃ except when the curting time was 1 day(p<0.05) 4. Among Group 2, Group 3 and Group 4, Group 5, the pressure had no effect on polymerization except when the curing time was 12 hours(p<0.05) 5. Between Group 1 and Group 2, the method of storage had no effect on polymerization except when the curing time was 1 hour(p<0.05)

Air abrasive technique 을 이용한 복합레진 수복 증례

장기택,이상훈,한세현,이창우 大韓小兒齒科學會 1997 大韓小兒齒科學會誌 Vol.24 No.4

The air abrasive technique is a non-mechanical method by which teeth are treated before restoration and stains and calculi are removed from tooth surfaces using the kinetic energy of small particles. The air abrasive technique in dentistry was first introduced in the 1950's with as instrument called 'Airdent'. But, as the main restorative materials of the period were amalgam and gold, and the instrument's inability to control the flow of particles caused the particles to be spread throughout the clinics, widespread use was not possible. In the 1990's, as these techincal problems were solved and more interest in new restorative materials rose in an effort to preserve sound tooth structure, new developments took place in instruments related to the air abrasive technique. The air abrasive technique produces less pressure, vibration and heat that might cause patient discomfort and facilitates the preservation of sound tooth structure. It also reduces the need for anesthesia and is less harmful to the pulp. Other advantages include increase in dentin bonding strength of composite resin, lower possibility of saliva contamination and maintenance of a dry field. But there is not direct contact between the nozzle and the tooth, the operator cannot use his or her tactile sense and must rely solely upon visual input. Other disadvantages are : the tooth preparation depends on the operator's ability ; alpha-alumina particles, after bouncing off the tooth surface, cause damage to dental mirrors ; the equipment is expensive and takes up a certain amount of space in the clinic. The author conducted case report using the air abrasive technique on patient visiting the Department of Pediatric Dentistry at Seoul National University Dental Hospital and arrived at the following conclusions. 1. The tooth preparation capability of different air abrasive devices varied widely among manufacturers. 2. It was more effective in treating early caries lesions and stains compared to lesions where caries had already progressed to produce soft dentin. 3. The cold stream and noise caused by the evacuation system was a major cause of discomfort to pediatric patients. 4. As there is no direct contact with tooth surface when using the air abrasive technique for tooth preparation, considerable experience and skill is required for proper tooth preparation.

A2024-T4 同種材 마찰용접시 업셋압력이 접합특성에 미치는 영향

고봉학,장승수,여상은,민택기 忠南大學校 産業技術硏究所 2002 산업기술연구논문집 Vol.17 No.2

The study deal with the strength of weld zone, the effect of upset pressure and microstructure of weld zone which are obtained from the variation of upset pressure in the friction welding A2024-T4 similar materials. The welding conditions was fixed welding condition of rotation speed 1000rpm, friction pressure 150Mpa, friction time 1.0sec and upset time 4.0sec. The upset pressure was variationed from 200Mpa to 320Mpa. The result are summarized as follows: 1. As a result of tensile test, the maximum tensile strength was obtained 503Mpa and it corresponds to about 104% of base metal tensile strength. tensile fracture surfaces appeared deep Dimple in heat affected zone(HAZ) 2. As a result of vickers hardness test, the maximum hardness was obtained 136Hv in friction welding interface and width of heat affected zone(HAZ) appeared 0.2mm. 3. As a result of analyzing th microstructure of weld zone. Me or Mn compounds of friction welding interface come out flash zone by centrifugal force and upset pressure, the microstructure of weld zone is recrystallized.

유구치 기성 금관의 변연 적합도에 관한 연구

우주형,장철호,김정욱,장기택,김종철 대한소아치과학회 2007 大韓小兒齒科學會誌 Vol.34 No.1

본 연구의 목적은 발거된 기성 금관 수복 유구치를 대상으로 변연 적합도를 관찰 분석하는 것이다. 서울대학교 치과 병원 소아치과에서 수거한 3M사의 기성 금관 수복 유구치를 대상으로 하였다 상악 제 1유구치 42개, 상악 제 2유구치 25개, 하악 제 1유구치 37개, 하악 제 2유구치 28개를 대상으로 기성 금관의 변연에 따라 치근 절단한 후 단면을 Fine Pix S602 디지털 카메라로 촬영한 후 Kappa image base program을 이용해 두각 부위 및 임의로 20 부분의 변연 간격과 전체 기성 금관 면적 중 변연 간격의 면적이 이루는 비율을 측정하여 다음과 같은 결과를 얻었다. 1. 평균 변연 간격은 상악 제 2유구치, 하악 제 1유구치, 하악 제 2유구치, 상악 제1 유구치 순으로 높았다 (P<0.05). 2. 평균 변연 간격 면적의 비율은 치아의 종류에 관계없이 약 20%를 상회하는 값을 보였다. 3. 상악 제 1,2유구치에서는 근심면의 변연 간격이 가장 컸고, 하악 제 1유구치에서는 원심 설면, 하악 제 2유구치에서는 협면에서 변연 간격이 가장 큰 값을 보였다. Stainless steel crowns are invaluable restorative material for the treatment of badly broken down primary teeth in pediatric dentistry. But it is difficult to fit margin because selection of size is not easy and they are not adjusted for Korean children. The purpose of this study was to examine and analyze the marginal adaptation of stainless steel crown of posterior primary tooth. Marginal surface was taken by Fine Pix S602 digital camera and measurements of crown were recorded at 20 points that were randomly selected for marginal gap evaluation by Kappa image base program. 1. Mean marginal gap were large upper 2nd primary molar, lower 1st primary molar, lower 2nd primary molar, upper 1st primary molar in order(p<0.05). 2. Mean marginal surface dimension ratio was more than 20% irrespective of tooth. 3. Largest amount of marginal gap was shown at mesial surface in upper 1st, 2nd primary molar and distolingual surface in lower 1st primary molar, buccal surface in lower 2nd primary molar.

Twin Block을 이용한 Ⅱ급 부정교합의 치료증례

박수진,장기택,김종철 大韓小兒齒科學會 1998 大韓小兒齒科學會誌 Vol.25 No.1

Twin Blocks are simple bite-blocks that effectively modify the occlusal inclined plane to induce favorably directed occlusal forces by causing a functional mandibular displacement. These devices use upper and lower bite-blocks that engage on occlusal inclined planes. Twin Blocks use the forces of occlusion as the functional mechanism to correct the malocclusion. To get an excellent result in the treatment by using the Twin Block appliances, proper case selection must be needed. Twin Block treatment is performed in two stages. Twin Blocks are used in the active phase to correct the anteroposterior relationship and establish the correct vertical dimension. Once this phase is accomplished, the Twin Blocks are replaced with an upper Hawley type of appliance with an anterior inclined plane, which is then used to support the corrected position as the posterior teeth settle fully into occlusion. The Twin Block is the most comfortable, the most esthetic ane the most efficient of all the functional appliances. Twin Blocks have 24 hours per day and can eat comfortably with the appliances in place. From the moment Twin Blocks are fitted, the appearance is noticeably improved. There is less interference with normal function. Integration with conventional fixed appliances is simpler than with any other functional appliance. Twin Blocks allow independent control of upper and lower arch width. Appliance design is easily modified for transverse and sigittal arch development. The authors treated ClassⅡ malocclusion with Twin Blocks, and the results as follows: 1. Rapid profile improvement was achieved in 2-3 months. 2. There was excellent patient cooperation. 3. Severe overjet and overbite were reduced. 4. Class Ⅱ molar relationship was changed to Class Ⅰ.

Russell-Silver Syndrome

이진,장기택,김종철 大韓小兒齒科學會 2002 大韓小兒齒科學會誌 Vol.29 No.1

러셀-실버 증후군(Russell-Silver Syndrome)은 출생시 저신장, 편측성 비대칭과 성기관 발육의 다양성 및 그 외 cafe-aulait 반점, 만지증 등의 특징과 태아기부터 발현되는 성장지연을 보이는 질환이다. 이 신드롬과 관련된 안면 특징은 작고 삼각형의 얼굴과 짧은 안면고경, 구각부가 아래로 쳐진 입모양(shark's mouth), 작은 하악골과 흔히 좌우 비대칭이 있는 것이다. 현재까지 보고되고 있는 러셀-실버 증후군의 주요한 구강내 소견은 높은 구개궁(high-arched palate), 맹출 지연, 왜소치와 총생이다. 현재까지 세계적으로 약 150 증례가 보고되고 있으나, 치의학적으로는 극히 드물다. 본 증례는 출생전 성장지연, 저신장, 저체중 등 임상소견을 통해 러셀-실버 증후군으로 진단받았고 성장호르몬 치료를 받았고, 현재 치료 중이다. 이 두 증례를 러셀-실버 증후군의 구강내 특징을 보고하고, 관련 문헌을 고찰해 보고자 한다. Russel-Silver syndrome is a type of intrauterine growth retardation, characterized by short stature noted at birth, hemiatrophy or asymmetry, variation in sexual development and other abnormalities, including cafe-aulait pigmentation and clinodactyly. Facial features commonly associated with this syndrome are a small triangular face, decreased facial height, down-turned corners of the mouth(shark's mouth), a small mandible, and occasionally asymmetry. The major intra-oral features of the syndrome that have been reported are a high-arched palate, delayed tooth eruption, microdontia, hypodontia, and crowding. These cases were diagnosed at birth as Russel-Silver syndrome by clinical features such as prenatal growth retardation, short stature, low body weight, et al., and have been treated with growth hormone. The purpose of this paper is to report the dental findings of two patients and review the pertinent literature through the two cases.

유치열에서 Chlorhexidine Varnish와 Polyurethane Sealant의 Streptococcus mutans억제 효과에 대한 연구

이성혁,장기택,김종철 大韓小兒齒科學會 1998 大韓小兒齒科學會誌 Vol.25 No.1

Numerous chemical agents have been developed to reduce the activity of cariogenic bacteria. Of these, chlorhexidine is acknowledged as the most effective. Gel and mouthrinse have been the traditional method of its application in the mouth. It has been reported that chlorhexidine varnish has prolonged inhibitory effect on the number of streptococcus mutans in saliva and plaque. Recently, chlorhexidine varnish and polyurethane sealant have been developed to promote prolonged anticariogenic effect of chlorhexidine. Products containing 10% chlorhexidine varnish and polyurethane sealant have been developed to prevent caries by reducing the number of streptococcus mutans in the oral cavity. The purpose of this study is to investigate the inhibitory effect of chlorhixidine varnish and polyurethane sealant on streptococcus mutans in the primary dentition. Children with primary dentition containing no active carious lesion were divided into two groups. To the experimental group(n=11), chlorhexidine varnish and polyurethane sealant ( Chlorzoin , Knowell Therapeutic Technologies, Inc. Canada.) was applied once a week for four weeks according to the manufacturer's instruction. Only oral prophylaxis was performed on the control group(n=7). Cariesactivity was measured after using Chlorzoin SM(Knowell Therapeutic Technologies, Inc. Canada.) to incubate streptococcus mutans before and 5, 12, 24 weeks after initial varnish application. The following results were observed.: 1. There was statistically significant decrease in the number of streptococcus mutans in the experimental group for 5 weeks(P<0.01), 12 weeks(P<0.05) after the initial application. but, by 24 weeks significant difference had disappeared. 2. As the inhibitory effect of chlorhexidine varnish and polyurethane sealant application is not everlastion, reapplication at 12-24 weeks should be needed.