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).

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.

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).

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.

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)

Ferric sulfate를 이용한 유치치수절단술의 3년 후 임상평가

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

15.5% ferric sulfate solution을 이용하여 유치치수절단술을 시행한 유구치의 상태를 임상적, 방사선학적으로 평가를 하여 이를 20%로 희석한 formocresol로 치수절단술을 시행한 경우와 비교하였다. 1997년부터 1998년까지 서울대학교병원 소아치과에서 치료를 받은 건강한 환아를 대상으로 하였고, ferric sulfate를 이용한 치수절단술을 치료받은 30개의 치아와 20%로 희석한 formocresol로 치수절단술치료한 23개의 치아, 총 53개의 치아를 평균 34개월 후 follow-up하여 그 임상적, 방사선학적 상태를 조사하였다. ferric sulfate군의 전체적인 성공률은 80.0%이었고, formocresol군의 성공률은 81.0%이었다. 두 군의 결과 차이를 카이제곱검정의 통계방법으로 분석하였다. ferric sulfate군의 4개의 formocresol군의 4개의 차이가 외흡수를 보였고 근단부 치조골파괴는 ferric sulfate군의 3개와 formocresol군의 2개에서 보였다. ferric sulfate군과 formocresol군 사이의 성공률은 통계학적으로 유의한 차이를 보이지 않았다. The objective of this report is to assess clinically and radiographically the state of the primary molars pulpotomized with a 15.5% ferric sulfate solution. The subjects selected were healthy children treated at the pediatric dental clinic of the Seoul National University Hospital in Korea. Thirty teeth were pulpotomized with a ferric sulfate solution(FS). Another twenty-one teeth were pulpotomized with 20% dilute formocresol(FC). Clinical and radiographic data for the fifty-one primary molars were collected with a mean follow-up period of 34 months. The success rate for the FS group was 80.0%. The success rate for the FC group was 81.0%. The differences in the results between the two groups were analyzed statistically utilizing the chi square test. External root resorption was observed in four teeth of FS group and four of the FC group. Periapical bone destruction was observed in three of FS group and two of FC group. There were no significant statistical differences between the success rates for FS group and the FC group.

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.

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.

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.

All-in-one 접착제에서 초음파진동이 법랑질과 상아질의 결합강도와 레진침투에 미치는 영향

이범의,장기택,이상훈,김종철,한세현 大韓小兒齒科學會 2004 大韓小兒齒科學會誌 Vol.31 No.1

초기의 접착 시스템은 여러 단계의 술식을 필요로 하였으며 술자의 기술과 재료의 성질에 크게 좌우되었으나 최근 산부식, priming, adhesive를 한번에 적용할 수 있는 a11-in-one adhesive system이 등장하였다. 치과에서의 vibration의 이용은 치석의 제거 및 접착제의 점도를 낮추는데 이용되어왔으며 vibration은 접착제의 흐름성을 향상시켜 film thickness를 낮추어 수복물 주위의 미세누출을 줄이는데 도움을 준다. 이에 저자들은 all-in-one adhesive system에서 vibration이 법랑질과 상아질의 접착강도와 레진침투에 미치는 효과를 알아보고자 하였다. 법랑질 시편은 발거 후 실온에서 0.1% thymol 용액에서 보관된 30개의 건전한 사람의 대구치를 무작위로 10개씩 세군으로 나누고 근원심 방향으로 두 부분으로 분리하여 각각은 같은 접착제를 사용하고 초음파진동여부를 다르게 하였고, 아크릴 레진을 이용하여 직경 1-inch의 PVC관에 매몰한 후 협설면이 아크릴봉과 동일한 높이가 되도록 220-, 600-grit 연마지로 순차적으로 연마하였고 군당 10개씩 여섯 군으로 분류하였다. 1군과 2군은 Prompt L-Pop(3M-ESPE, Seefeld, Germany), 3군과 4군은 One-Up Bond F(Tokuyama Corp., Tokyo, Japan). 5군과 6군은 AQ bond(Sun Medical Co., Kyoto, Japan)를 제조사의 지시에 따라 도포하였다. 2군, 4군, 6군은 초음파 치석제거기를 이용하여 치면에 대고 15초간 진동을 가한 후 광중합하였다. 상아질 시편은 치관부 법랑질을 제거한 후 상아질면을 아크릴 봉과 동일한 높이가 되도록 하고 법랑질 시편과 동일하게 처리하였다. 이후 직경 2mm, 높이 3mm의 Teflon mold(Ultradent, U.S.A.)를 이용하여 복합레진을 충전한 후 40초씩 두 번에 나누어 광중합한 후 24시간동안 실온에서 증류수에 보관하였다. 열순환 시행한 후, 만능측정 기(Instron4465)로 전단결합강도를 측정하였으며 Resin tag의 양상을 비교하기 위해 각 군의 시편의 치질을 완전히 용해 시킨 후 표면을 주사전자현미경사진으로 관찰하여 다음과 같은 결과를 얻었다. 1. 법랑질에서 초음파 진동을 가한 군(2,4,6군)은 가하지 않은 군(1,3,5군)에 비해 평균 전단결합강도가 높게 나타났다. 그 차이는 AQ bond 군을 제외하고 통계적으로 유의하였다(p<0.05). 2. 상아질에서 초음파 진동을 가한 군(2,4,6군)은 가하지 않은 군(1,3,5군)에 비해 평균 전단결합강도가 높게 나타났다. 그러나 그 차이는 One-Up Bond F군을 제외하고는 통계적으로 유의한 차이가 없었다. 3. 전자 현미경 관찰에서 초음파 진동을 가한 군에서 더 많은 법랑질의 소실과 상아질에서 resin tag의 길이가 길었고 lateral branch의 수도 많이 관찰되었다. The objective of this study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration in enamel and dentin achieved with those gained using the conventional technique and vibration technique. For enamel specimens, thirty teeth were sectioned mesio-distally. Sectioned two parts were assigned to same adhesive system but different treatment(vibration vs non-vibration) Each specimen was embedded in 1-inch inner diameter PVC pipe with a acrylic resin. The buccal and lingual surfaces were placed so that the tooth and the embedding medium were at the same level. The samples were subsequently polished silicon carbide abrasive papers. Each adhesive system was applied according to its manufacture's instruction. Vibration groups were additionally nitrated for 15 seconds before curing. For dentin specimen, except removing the coronal part and placing occlusal surface at the mold level, the remaining procedures were same as enamel specimen. Resin composite(Z250 3M. U.S.A.) was condensed on to the prepared surface in two increments using a mold kit(Ultradent Inc., U.S.A.) Each increments was light cured for 40 seconds. After 24 hours in tap water at room temperature, the specimens were thermocycled for 1000cycles.. Shear bond strengths were measured with a universal testing machine(Instron 4465, England). To investigate infiltration patterns of adhesive materials, the surface of specimens was examined with scanning electron microscope. The results were as follows : 1. In enamel, the mean values of shear bond strengths in vibration groups(group 2,4,6) were greater than those of non-vibration group(group 1,3,5). The differences were statistically significant except AQ bond group. 2. In dentin, the mean values of shear bond strengths in vibration groups(group 2 4, 6) were greater than those of non-vibration groups(group 1,3,5). But the differences were not statistically significant except One-up Bond F group. 3. The vibration group showed more mineral loss in enamel and longer resin tag and greater number of lateral branches in dentin under SEM examination.