수종 음료수의 법랑질과 상아질 침식에 관한 연구

장기택 大韓小兒齒科學會 1997 대한소아치과학회지 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 대한소아치과학회지 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).

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.

Air abrasive technique 을 이용한 복합레진 수복 증례

장기택,이상훈,한세현,이창우 大韓小兒齒科學會 1997 대한소아치과학회지 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.

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)

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.

성장기 아동에서의 기능성 전치부 개교의 치료증례

김종철,장기택,손동수,김주훈 大韓小兒齒科學會 1996 대한소아치과학회지 Vol.23 No.3

Anterior openbite is defined as the lack of contacts between the functional occluding teeth on vertical line at centric occlusion and classified into functional and skeletal anterior openbite based on its causes and characteristics. Anterior openbite causes masticatory, speech, and esthetic problems in the growing children and difficulties in diagnosis, treatment, and the prediction of its prognosis. We are reporting on the treatment of anterior openbite in the growing children and the results follow as : 1. In the growing children with anterior openbite, the overbite could be increased by the treatment according to its causes and characteristics. 2. The prognosis is not determined by the presence or severity of oral habit but the skeletal tendency of the patient.

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 대한소아치과학회지 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.

유구치 기성 금관의 변연 적합도에 관한 연구

우주형,장철호,김정욱,장기택,김종철 대한소아치과학회 2007 대한소아치과학회지 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.

유구치 I급 와동에서 와동벽 위치와 중합광원에 따른 Microtensile Bond Strength 비교 연구

이현헌,장철호,김영재,김정욱,장기택 대한소아치과학회 2007 대한소아치과학회지 Vol.34 No.1

이번 실험에서는 중합수축 응력이 가장 크게 나타나는 유구치 I급 와동에서 와동벽의 위치와 중합광원의 변화에 의해 다르게 나타나는 응력의 차이를 microtensile bond strength (MTBS)를 이용하여 알아보는 것을 목적으로 하였다. 교합면 법랑질을 제거한 하악 제 2유구치 30개를 준비하여 I급 와동을 형성하였다. 제조사의 지시에 따라 상아질 접착제를 도포 후 3가지 중합광원: 할로겐 램프, 플라즈마, 발광다이오드를 이용하여 10개씩 광중합하였다. 복합레진을 한꺼번에 충전 후 각각의 중합기로 광중합하였다. 동일 치아에서 각각 치수벽과 축벽의 MTBS 측정용 시편을 제작하고 각 군을 중합광원과 와동벽 위치에 따라 할로겐 램프-축군, 할로겐 램프-치수벽군, 플라즈마-축벽군, 플라즈마-치수벽군, 발광다이오드-축벽군, 발광다이오드-치수벽군의 6개 군으로 분류하였다. 만능시험기에서 MTBS를 측정하고 파절편과 와동의 단면을 SEM을 이용하여 관찰하였다. 동일 중합광원에서 와동벽 간 비교는 T-test, 동일 와동벽에서 중합광원 간 비교는 One-way ANOVA와 Tukey's post hoc test를 이용하였고 Weibull 분포분석을 하였다. 동일 중합광원 군간 비교에서 모두 치수벽 시편의 접착강도가 축벽 시편에 비해 유의하게 높았으며 동일 와동벽 군간 비교에서 모두 중합광원에 따른 접착강도가 유의한 차이를 보이지 않았다. 축벽 시편이 치수벽 시편보다 낮은 Weibull 변수(m)를 나타내었고 SEM 관찰 결과 축벽 시편에서 보다 더 불균일한 접착이 이루어진 것을 알 수 있었다. The purpose of present study was to determine whether different kinds of curing lights can alter microtensile bond strength(MTBS) of class I cavity pulpal and axial wall specimens in primary molar. Thirty clean mandibular 2nd primary molar's occlusal enamel were removed and class I cavity, size of 2×4×2 mm was prepared. Dentin bonding agent was applied according to manufacturer' s manual. Each group was cured with Halogen Curing Unit, Plasma Curing Unit and LED Curing Unit. Composite resin was bulk filled and photo cured with same curing unit. MTBS specimens which size is 0.7×0.7×4 mm were prepared with low speed saw. Specimens were coded by their curing lights and wall positions (Halogen - Axial wall group, Halogen - Pulpal wall group, Plasma - Axial wall group, Plasma - Pulpal wall group, LED - Axial wall group, LED - Pulpal wall group). MTBS were tested at 1 mm/min cross Head speed by Universal Testing Machine. Fractured surface and bonding surface was observed with SEM. T-test between axial and pulpal specimens in each curing lights, one-way ANOVA among different curing light specimens in each wall positions were done. Weibull distribution analysis was done. The results were as follows: Mean MTBS of pulpal wall specimens were significantly greater than that of axial wall specimens at each curing units(p<.05). There was no significant difference in the MTBS among three curing units at axial wall and pulpal wall. In Weibull distribution, pulpal wall specimens were more homogeneous than axial wall specimens.