• 대한치과보철학회지
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• 제47권3호
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• pp.295-300
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• 2009

연구목적: 현대의학의 발달로 고령 인구가 증가함에 따라 부분 무치악이나 완전 무치악 환자의 비율이 증가되고 있다. 고령 환자는 전신적 질환이 동반되는 경우가 흔하므로 보철 치료 시에도 전신적인 건강 상태 및 경제적 여건에 대한 고려가 필요하다. 고령의 환자나 전신적 질환자에 있어 임플란트 등의 치료보다 가철성 국소의치가 선호되고 실제로 많이 적용되고 있으나 기존의 금속-아크릴 국소의치는 많은 한계점을 가지고 있다. 전치부에 금속 클래스프가 위치하여 비심미적이고 미중합 레진에 의한 알레르기 반응이 있으며 지대치에 가해지는 응력이 크며, 파절 시 수리가 용이하지 않다. 또한 대부분의 경우 지대치에 주조 금관의 제작이 필요하며 이로 인해 추가적인 고가의 보철비용을 부담하여야 하고 제작과정이 복잡할 뿐 아니라 장기간의 치료와 여러 번의 내원이 필요하다. 반면, 최근 이용빈도가 증가하고 있는 Valplast$^{(R)}$ 탄성 국소의치는 Nylon 재질로 생체친화성이 높고 심미적이고 가벼우며 수리가 용이한 장점이 있다. 또 간단한 진료 과정과 짧은 제작기간 후 의치를 장착할 수 있다. 본 증례에서는 장기간의 치료기간과 다수의 내원이 어려운 전신 질환자 및 예후가 불량한 환자에서 Valplast$^{(R)}$ 탄성국소의치를 적용한 예를 보고하고자 한다. 결과 및 결론: 증례에서 환자들은 만성 질환, 암 등의 전신적, 소모성 질환을 앓고 있거나 개구 제한 또는 예후가 불량한 잔존 지대치 등 통상적인 보철치료가 힘든 경우였다. 이러한 환자들에게 기존의 금속-아크릴 국소의치는 신체적으로나 경제적인 이유로 적용이 어려워 대신 추가적인 보철물의 제작이 필요없고, 제작과정이 간단한 Valplast$^{(R)}$ 탄성 국소의치를 적용하였다. 환자들은 평균 1-2회의 주기적 체크를 했고 현재까지 동통이나 파절 등의 불편감이 없이 잘 사용하고 있다. 여러 증례에서 기존의 가철성 의치의 단점을 보완하는 탄성의치를 이용하여 만족한 결과를 얻었기에 보고하는 바이다.

• 대한치과보철학회지
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• 제47권3호
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• pp.286-294
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• 2009

연구목적: 우리 사회가 선진화 됨에 따라 장애인과 장애인의 사회복지에 대한 관심이 점차 증가되고 있으며 장애인의 의료환경에 대한 연구도 차츰 늘어가고 있다. 하지만 그 동안 증가하는 장애인 치과 진료의 수요 및 관심에 비해 장애인 보철 진료에 대한 연구가 전무한 실정이었다. 본 연구는 치과의사가 바라본 현행 대한민국의 장애인 보철 진료 실태와 인식에 관해 조사하였다. 연구 재료 및 방법: 전국의 장애인 진료를 하는 치과 병의원 및 복지기관, 보건소의 치과의사 87명을 대상으로 총 11문항으로 구성된 설문지를 발송하여 68부의 유효한 설문지를 회수하여 통계 분석하였다. 결과 및 결론: 1. 조사 대상 치과의사 중 45.6%가 일반인과 마찬가지로 장애인에게도 심미보철 진료가 필요하다는 데에 긍정적으로 답변하여 시대의 흐름에 따라 과거 기능회복 위주였던 장애인 치과치료에서 점차 심미적인 고려가 필요함을 보여주었다. 2. 보철 진료의 이상적인 진료비 지불방식에 대한 조사결과 정부로부터의 재정지원이 필요하다는 의견이 79.4%를 차지하였고, 그 중 66.7%의 응답자가 그 규모를 일반보철 수가의 최소 50%이상을 정부가 지원하는 것이 적절하다고 응답했다. 현재 우리나라 장애인 보철 진료 실태에 관해 97.1%의 응답자들이 열악하다고 인식하고 있었다. 이러한 문제의 원인으로는 장애인의 협조도 부족 문제를 제외하면 재정적인 부분이 가장 컸다. 따라서 향후 정부의 장애인 보철 진료에 대한 현실적인 지원 방안이 마련되어야 할 것으로 생각된다.

• 대한치과보철학회지
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• 제45권5호
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• pp.644-652
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• 2007

Statement of problem: Resonance frequency analysis is evaluated as the non-invasive and objective method for the evaluation of implant stability and has been increasingly used. It is necessary to evaluate the factors affect the ISQ measurement stability. Purpose: This study was performed to evaluate the effect of the autoclave sterilization and reuse of $Smartpeg^{TM}$ on ISQ measurement. Material and methods: $SmartPeg^{TM}$ (Integration Diagnostics Ltd., $G\ddot{o}teborg$, Sweden) of autoclave group (A) was autoclave sterilized 9 times and $Smartpeg^{TM}$ of reuse group (R) was reused 9 times. Ten $SmartPeg^{TM}s$ were allocated to each group and after each autoclave sterilization and reuse, implant stability quotient (ISQ) values were measured 3 times from the two directions a and b at a right angle. $Osstell^{TM}$ mentor (Integration Diagnostics Ltd. $G\ddot{o}teborg$, Sweden) was used and type 1 (article no. 100353) $Smartpeg^{TM}$ was selected according to $Smartpeg^{TM}$ reference list. Osstem Implant US II future (Osstem Co., Seoul, Korea) in $4.0mm{\times}11.5mm$ was embedded in the self-curing acrylic resin ($Orthojet^{(R)}$, Lang Dental, U.S.A.). Data was statistically analyzed by one-way ANOVA $({\alpha}=.05)$ and scheffe test was done where a significant difference exist. Correlation test was also done between ISQ value and the number of autoclave sterilization or reuse. Results: 1. In autoclave group, the means and sd. of ISQ value before autoclave sterilization were $84.97{\pm}0.41,\;84.93{\pm}0.74$ at direction a and b. There was significant differences between autoclave groups at direction a and b (P=.000). 2. In reuse group, the means and sd. of ISQ value before reuse were $85.40{\pm}0.62,\;85.50{\pm}0.57$ at direction a and b. There was no significant difference between reuse groups at direction a and b (P>.05). 3. There was a weak positive correlation between the number of reuse and ISQ value at direction a and b (${\gamma}=.207$ and .246, P<.01). Conclusion: Within the limitations of this study, the following conclusions were drawn. Till ninth reuse of $Smartpeg^{TM}$, the ISQ measurement stability did not be affected. After twice autoclave sterilization of $Smartpeg^{TM}$ the ISQ measurement stability was affected.

• 대한치과보철학회지
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• 제45권5호
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• pp.611-620
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• 2007

Statement of problem: Second-generation indirect composite resins have been improved flexural strength, compressive strength, hydrolytic degradation resistance, wear resistance compared to first-generation indirect composite resins, but there are still some problems as hydrolysis and low wear resistance. Some manufacturers claim that wear resistance of their materials has been improved, but little independent study has been published on wear properties of these materials and the properties specified in the advertising materials are largely derived from in-house or contracted testing. Purpose: This study was to evaluate the wear of indirect composite resins (SR Adore, Sinfony, Tescera ATL) and gold alloy against the human enamel. Material and method: Extracted human incisors and premolars were sectioned to $2{\times}2{\times}2mm$ cube and embedded in the clear resin and formed conical shaped antagonist to fit the jig of pin-on-disk tribometer. Total 20 antagonists were stored in distilled water. Five disk samples, 24mm in diameter and 1.5mm thick, were made for each of three groups of indirect composite resins and gold alloy group, and polished to #2,000 SiC paper on auto-polishing machine. Disk specimens were tested for wear against enamel antagonists. Wear test were conducted in distilled water using a pin-on-disk tribometer under condition (sliding speed 200rpm contact load 24N, sliding distance 160m). The wear of the enamel was determined by weighing the enamel antagonist before and after test, and the weight was converted to volumes by average density. The wear tracks were analyzed by scanning electron microscopy and surface profilometer to elucidate the wear mechanisms. Statistical analysis of the enamel wear volume, wear track depth and wear tract width of disk specimens were accomplished with one-way ANOVA and the means were compared for significant differences with Scheffe's test. Results: 1. The enamel wear was most in gold alloy, but there were no statistically significant differences among all the groups (P>.05). 2. In indirect composite resin groups, the group to make the most shallow depth of wear tract was Sinfony, followed by Tescera ATL, SR Adoro (P<.05). Gold alloy was shallower than Sinfony, but there was no statistically significant difference between Sinfony and gold alloy (P>.05). 3. The width of wear tract of SR Adore was larger than the other groups (P<.05), and there were no statistically significant differences among the other groups (P>.05). 4. SEM analysis revealed that Sinfony and gold alloy showed less wear scars after test, Tescera ATL showed more wear scars and SR Adore showed the most. Conclusion: Within the limits of this study, Sinfony and gold alloy showed the least wear rates and showed similar wear patterns.

• 대한치과보철학회지
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• 제45권5호
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• pp.675-686
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• 2007

Statement of problem: Titanium nitride(TiN) coatings are the most general and popular coating method and used to improve the properties of metallic surface for industrial purposes. When TiN coating applied to the abutment screw, frictional resistance would be reduced, as a results, the greater preload and prevention of the screw loosening could be expected. Purpose: The purpose of this study was to investigate mechanical properties of TiN coated film of various coating thickness on the titanium alloy surface and to evaluate proper coating thickness. Material and method: 95 Titanium alloy (Ti-6Al-4V) discs of 15 mm in diameter and 3 mm in thickness were prepared for TiN coating and divided into 7 groups in this study. Acceding to coating deposition time (CDT) with TiN by using Arc ion plating, were divided into 7 groups : Group A (CDT 30min), Group B (CDT 60min), Group C (CDT 90min), Group D (CDT 120min), Group E (CDT 150min), Group F(CDT 180min) and Group G (no CDT) as a control group. TiN coating surface was observed with Atomic Force Microscope(AFM), field emission scanning electron microscopy(FE-SEM) and examined with scratch tester, wear tester. Result: 1. Coating thickness fir each coated group was increased in proportion to coating deposition time. 2. Surface of all coated groups except Group A was homogeneous and smooth. However, surface of none coated Group G had scratch. 3. Adhesion strength for each coated group was increased in proportion to coating deposition time. 4. Wear resistance for each coated group was increased in proportion to coating deposition time. 5. Surface roughness in Group A, B, C was increased in proportion to coating deposition time. But, surface roughness in Group D, E, F was showed decreased tendency in proportion to coating deposition time. Conclusion: According to coating deposition time, mechanical properties of TiN coated film were changed. It was considered that 120 minutes coating deposition time ($1.32{\mu}m$ in coating thickness) is necessary.

• 대한치과보철학회지
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• 제45권5호
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• pp.567-578
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• 2007

Statement of problem: The endodontically treated tooth is generally restored with post and core, owing to the brittle and the loss of large amount of tooth structure. As periodontal treatment was developed, there are many cases that periodontally involved teeth used in prosthetic treatment. Purpose: The purpose of this study was to analyze the stress distribution in the dentin and post structures by the various post materials and the amount of remaining alveolar bone height. Material and method: The 3-dimensional finite element models of mandible 1st premolars were divided into six types according to the various amount of remaining alveolar bone and post type. All types were modeled using equal length, diameter and shape of the post. Three types of post and core materials were used: prefabricated titaniumpost and amalgam core, prefabricated stainless steel post and amalgam core, and cast gold post and core. 300 Newton force was applied to functional cusp of mandible 1st premolar. Results: The results were as follows: First, there was no apparent difference in the pattern of stress distribution according to the alveolar bone condition concentrate on the post middle area. Second, there was difference in pattern of stress distribution according to the core materials, gold post and core generated same than amalgam core. Third, there was no apparent difference in the pattern of stress distribution within the dentin according to the post and core materials. But a cast gold post and core generated the lowest maximum stress value, a stainless steel post generated the highest maximum stress value. Fourth, in the reduced alveolar bone model, maximum stress value is 1.5 times than that of the normal alveolar bone model. Conclusion: Within the limitations of this study, to provide minimal stress to the root with alveolar bone reduced, the post length may be as long as apical seal was not destroyed. To prevent fracture of tooth, it is rational to use gold alloy which material was good for stress distribution for post materials.

• 대한치과보철학회지
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• 제45권5호
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• pp.589-600
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• 2007

Statement of Problem: Titanium has many advantages of high biocompatibility, physical porperties, low-weight, low price and radiolucency, but it is incompatible with conventional dental porcelain due to titanium's oxidative nature. Many previous studies have shown that they used the method of sandblast surface treatment prior to porcelain application, the researchs are processing about the method of acid etching or surface coating. Purpose: The purpose of this research is to study the effect on bond strength between titanium and porcelain when using macro-surface treatment and micro-surface treatment and macro and micro surface treatment. Material and method: In this study, we evaluated the bond strength by using 3-point bending test based on ISO 9693 after classified 7 groups-group P : polished with #1200 grit SiC paper, group SS : sandblasted with $50{\mu}m$ aluminum oxides, group LS : sandblasted with $250{\mu}m$ alumium oxides, group HC : treated with 10% hydrochloric acid, group NF : treated with 17% solution of fluoric acid and nitric acid, group SHC : treated with 10% hydrochloric aicd after sandblsting with $50{\mu}m$ alumium oxides, group SNF treated with 17% solution of fluoric acid and nitric acid. Results : Within the confines of our research, the following results can be deduced. 1. Group SS which was sandblasted with $50{\mu}m$ aluminum oxides showed the highest bond strength of 61.74 MPa and significant differences(P<0.05). The bond strengths with porcelain in groups treated acid etching after sandblasting decreased more preferable than the group treated with sandblasting only. It gives significant differences(P<0.05). 2. After surface treatments, the group treated with sandblasting showed irregular aspect formed many undercuts, in the SEM photographs. The group treated with hydrochloric acid had the sharp serrated surfaces, the group treated with the solution of fluoric acid and nitric acid had the smooth surfaces, the group with sandblasting and hydrochloric acid had irrigular and porous structure, the group with sandblasting and the solution of fluoric acid and nitric acid had crater-like surfaces. But all of the groups treated with acid etching was not found and undercut. Conclusion: In above results, average surface roughness increase, bond strength also increase, but surface topographs influences more greatly on bond strengths.

• 대한치과보철학회지
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• 제45권5호
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• pp.653-664
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• 2007

Statement of problem: The screw detorque value is a measure of the preload remaining in the screw just before detorquing. Purpose: This study evaluated the effect of different screw tightening sequences and tightening methods on detorque values for a well-fitting implant superstructure. Material and method: An implant superstructure that connected directly to four implants (Astra Tech) was fabricated on a fully edentulous mandibular acrylic resin model. Six well-fitting dental stone casts were made with a pickup impression of the superstructure from the acrylic resin model. To evaluate the effect of three screw tightening sequences (1-2-3-4, 2-4-3-1, and 2-3-1-4) and two tightening methods (2-step and 1-step) on the stability of screw joint, the detorque values for a well-fitting implant superstructure were measured twice after screw tightening using 20 Ncm. Detorque values were analyzed using multi-way analysis of variance and two-way analysis of variance at a .05 level of significance. Results: 1. The mean detorque values for three screw tightening sequences were 12.3 Ncm, 12.6 Ncm, and 12.0 Ncm, respectively. 2. The mean detorque values for two screw tightening methods were 12.0 Ncm, and 12.2 Ncm, respectively. 3. The mean of mimimum detorque values for three screw tightening sequences and for two tightening methods were 10.6 Ncm, 11.1 Ncm, 10.5 Ncm, and 9.8 Ncm, respectively. 4. No statistically significant differences among the variables of screw tightening sequence and tightening method were found (p>.05) for detorque values and for mimimum detorque values. Conclusion: Within the limitations of this study, the screw tightening sequence and tightening method did not have a significant effect on the detorque values for a well-fitting implant superstructure.

• 대한치과보철학회지
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• 제45권5호
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• pp.601-610
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• 2007

Statement of problem: The adhesion between titanium and ceramic is less optimal than conventional metal-ceramic bonding, due to reaction layer form on cast titanium surface during porcelain firing. Purpose: This study characterized the effect of titanium-ceramic adhesion after gold and TiN coating on cast and wrought titanium substrates. Material and method: Six groups of ASTM grade II commercially pure titanium and cast titanium specimens$(13mm{\times}13mm{\times}1mm)$ were prepared(n=8). The conventional Au-Pd-In alloy served as the control. All specimens were sandblasted with $110{\mu}m\;Al_2O_3$ particles and ultrasonically cleaned for 5min in deionized water and dried in air before porcelain firing. An ultra-low-fusing dental porcelain (Vita Titankeramik) was fused on titanium surfaces. Porcelain was debonded by a biaxial flexure test at a cross head speed of 0.25mm/min. The excellent titanium-ceramic adherence was exhibited by the presence of a dentin porcelain layer on the specimen surface after the biaxial flexure test. Area fraction of adherent porcelain (AFAP) was determined by SEM/EDS. Numerical results were statistically analyzed by one-way ANOVA and Student-Newman-Keuls test at ${\alpha}=0.05$. Results: The AFAP value of cast titanium was greatest in the group 2 with TiN coating, followed by group 1 with Au coating and the group 3 with $Al_2O_3$ sandblasting. Significant statistical difference was found between the group 1, 2 and the group 3 (p<.05). The AFAP value of wrought titanium was greatest in the group 5 with TiN coating, followed by the group 4 with Au coating and the group 6 with $Al_2O_3$ sandblasting. Conclusion: No significant difference was observed among the three groups (p>.05). The AFAP values of the cast titanium and the wrought titanium were similar. However the group treated with $Al_2O_3$ sandblasting showed significantly lower value (p<.05).

• 해양환경안전학회지
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• 제21권6호
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• pp.637-644
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• 2015

항내 정온도 평가는 이상파 및 평상파 조건에 대해 수행이 되어야 하나, 어항개발 시 이루어지는 평가는 이상파에 대해서만 수행되고 있다. 축산항, 교암항, 궁평항 및 시산항에 대한 사례를 통해 해역이용협의 시 정온도 평가에 대한 실태를 분석하였다. 대상항 모두 이상파에 대한 항내 정온도를 평가를 수행하였으나, 목표 정온도를 만족하지 못하였다. 평상파에 대한 정온도는 가동률로 평가하며, 가동률을 평가하기 위해서는 장기간의 파랑관측이 필요하나 수행되지 않고 있었다. 가동률에 대한 평가는 계획의 적정성과 관련 있는 평가항목이기 때문에 개발로 인한 해양환경에 미치는 악영향을 최소화할 수 있는 계획의 수립과 어업인들의 정주환경 개선을 평가하기 위해서는 수행이 필요하다. 정온도 평가를 위해서는, 정온도 평가에 대한 이해가 선행되어야 하고, 장기간의 파랑관측이 수행되어야 하며, 평상파 및 이상파에 대한 평가절차를 명확히 해야 한다. 그리고 실효적인 계획이 수립될 수 있도록 조석정보와 같은 파랑정보의 제공 및 정온도를 평가할 수 있는 가이드라인의 수립이 필요하다.