• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.1003-1017
• /
• 2005

이 논문은 단일조사 저출력 $CO_2$ Laser조사가 치주인대 섬유아세포의 증식과 분화에 미치는 영향을 살펴보고 가장 효과적인 에너지와 파워밀도(power density)를 알아보기 위해 다음과 같이 실험하였다. 0.5W 출력, 10.6 ${\mu}m$ 파장, 50 Hz 연속형 $CO_2$ Laser를 사용하여, 실험군은 laser tip과 배양된 세포 사이의 거리를 2cm, 3cm으로 나누고, 조사시간을 1초, 3초로 나누어 4개의 군으로 설정하였고 대조군은 laser를 조사하지 않은 군으로 하였다. 치주인대 섬유아세포의 증삭정도와 골모세포로의 분화정도를 보기 위하여 각각 MTT 실험과 ALP activity 실험을 시행하여 다음과 같은 결과를 얻었다. 1. Laser를 조사하고 난 후 5일째에, 모든 군에서 유의하게 세포가 증식되는 것을 확인할 수 있었고 조사방법간에 유의한 차이가 없었다. 2. 대조군과 살험군에서 0일째에 비하여 3일째, 5일째, 7일째, 10일째에 통계적으로 유의 하게 ALP activity가 증가하였고, 이중 2cm,1sec 군을 제외하면 3일째에서 가장 높은 ALP activity 값을 보였다. 특징적으로 2cm,1sec 군은 3일째부터 10일까지 통계적으로 유의하지는 않지만 시간이 지남에 따라서 ALP activity가 증가함을 보였다. 7일과 10일째에는 2cm,1sec, 3cm,3sec군에서 다른 군에 비하여 큰 activity값을 보였다. 이번실험에서 저출력 $CO_2$ Laser 조사는 세포의 증식보다는 분화에 더 큰 영향을 끼쳤고, 2cm, 1sec, 3cm, 3sec 군이 치주인대 섬유아세포의 분화에 가장 효과적인 laser 조사방법으로 분석되었다.

• Journal of Periodontal and Implant Science
• /
• v.30 no.1
• /
• pp.11-27
• /
• 2000

The purpose of this study was to evaluate the clinical effects of Dipotassium glycyrrhizinate, Allantoin, Hinokitiol, Cetylpyridinium chloride containing gel($Dentheth^{(R)}$) on periodontitis. 41 patients with sites having pocket depth of 4-6mm were selected for the study. We classified 2 groups which consisted of 21 patients in the test group(exp.) and 20 patients in the control(placebo) respectively. Following a baseline examination, plaque and calculus were removed and then the experimental gel were handed out to the patients and topical application regimens were initiated. During the 4-week experimental period, pocket depth, bleeding on probing, gingival index, plaque index as a clinical parameters were measured in the baseline, 2 weeks, 4 weeks respectively. A questionnaire was delivered to each patients in 2 weeks, 4 weeks respectively. The results were as follows : 1. Probing pocket depth showed a significant difference in the Exp. group compared with the control group in the changes from baseline to 2 weeks(p<0.05), but there was no significant difference between the groups in the changes from baseline to 4 weeks, from 2 weeks to 4 weeks(p<0.05). 2. The Exp. group showed a significant difference compared with the control group in the changes from baseline to 2 weeks, from baseline to 4 weeks, from 2 weeks to 4 weeks in bleeding on probing(p<0.05). 3. The gingival index showed a significant difference compared with the control group in the changes from baseline to 2 weeks, from baseline to 4 weeks, from 2 weeks to 4 weeks after 4 weeks use of a gel(p<0.05). 4. The plaque index showed a significant difference in the Exp. group compared with the control group in the changes from baseline to 2 weeks(p<0.05), but there was no significant difference between the groups in the changes from baseline to 4 weeks, from 2 weeks to 4 weeks(p<0.05). 5. A questionnaire was consisted of 5 kinds as to bleeding, pus discharge, pain, burning sensation, patient's satisfaction and all of the questions showed a significant difference compared with the control group in the changes from 2 weeks to 4 weeks(p<0.05). 6. During the 4-week experimental period, important side-effects were not finded out, but each groups had one patient appealed nausea or discomfort respectively. These results indicate that application of periodontitis medical gel was useful as an additional aid of mechanical treatment.

• Journal of Periodontal and Implant Science
• /
• v.35 no.3
• /
• pp.609-621
• /
• 2005

1. 목적 Osteotome 상악동거상술(Bone Added Odteotome Sinus Floor Elevation ; 이하 BAOSFE) 과 동시에 식립한 임프란트($Br{\aa}nemark$, ITI)의 예상 생존율에 대해 현재까지 정확히 알려진 바는 없었으며, $Br{\aa}nemark$ Ti-Unite 과 ITI SLA 임프란트의 표면에 대한 비교 연구 또한없었다. 이번 연구는 BAOSFE 술식과 동시에 식립한 $Br{\aa}nemark$ Ti-Unite 과 ITI SLA 임프란트의 임상 결과를 비교, 평가하고 초기 치유기간 동안의 이식골 높이의 변화를 방사선학적으로 관찰하여 두 가지 임프란트 시스템을 비교해 보고자 한다. 2. 방법 위축된 상악 구치부를 갖는 22명의 환자를 대상으로, BAOSFE술식과동시에 $Br{\aa}nemark$ Ti-Unite(11명, 13 임프란트)임프란트와 ITI SLA(11명, 18 임프란트)임프란트를 식립하였다. 수술 전, 임프란트 식립 직후, 술후 6개월의 파노라마 방사선 사진을 촬영하여 비교 및 평가에 사용하였다. 각 임프란트 시스템의 생존율을 측정하고, 술전 상악동저 높이와 식립된 임프란트 길이를 참고하여 이식골 높이의 방사선학적 변화를 평가하였다. 3. 결과 평균12개월의 추적기간 결과, $Br{\aa}nemark$ Ti-Unite 임프란트의 생존율은 100%(13/13 임프란트)이었으며, ITI SLA 임프란트의 생존율은 94.4%(17/18 임프란트)이었다. 초기 치유 기간인 6개월 동안 평균 이식골 높이의 감소는 $Br{\aa}nemark$ Ti-Unite 임프란트에서 0.67mm(10.73%), ITI SLA 임프란트에서는 0.55mm(8.18%)로 나타났다. 두 가지 임프란트 시스템 간의 유의성 있는 차이는 보이지 않았다. 4. 고찰 BAOSFE 술식과 동시식립한 $Br{\aa}nemark$ Ti-Unite 과 ITl SLA 임프란트는 위축된 상악 구치부를 갖는 환자에서 효과적인 치료방법이 될 수 있으며, 임프란트 표면에 따른 이식골의 치유 반응은 두 가지 임프란트 시스템에서 유사한 양상으로 일어남을 알 수 있었다.

• Journal of Periodontal and Implant Science
• /
• v.50 no.6
• /
• pp.368-378
• /
• 2020

Purpose: Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss. Methods: Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008-2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions. Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed. Results: Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis. Conclusions: This population-based cross-sectional study indicates that low serum 25(OH) D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.

• The Journal of Korean Academy of Prosthodontics
• /
• v.55 no.2
• /
• pp.151-155
• /
• 2017

Purpose: The aim of this study was to evaluate screw removal torque of the two-piece zirconia abutment with the novel titanium component compared to the conventional one-piece titanium abutment in the internal connection implant before and after dynamic cyclic loading. Materials and methods: Two types of the abutment assemblies with internal connection were prepared and divided into the groups; titanium abutment-titanium abutment screw assemblies as control, and zirconia abutment-titanium socket-titanium abutment screw assemblies as experimental group. A total of 12 abutments and implants were used of six assemblies each group. Each assembly was tightened to 30 Ncm. A cyclic load of 300 N at an angle of 30 degrees in reference to the loading axis was applied until one million cycles or failure. The removal torque values (RTVs) of the abutment screws were measured with a digital torque gauge before and after cyclic loading. The RTVs of the pre load and post load were analyzed with t-test, and P-values < .05 were considered statistically significant. Results: The assemblies of both groups survived all after the dynamic cyclic loading test without screw loosening. The statistically significant differences were found between the mean RTVs before and after the cyclic loading in both groups (P < .05). The RTV differences for the control and the experimental group were $-7.25{\pm}1.50Ncm$ and $-7.33{\pm}0.93Ncm$, respectively. Statistical analysis revealed that the RTV differences in both groups were not significantly different from each other (P > .05). Conclusion: Within the limitation of this study, the two-piece zirconia abutment with the titanium component did not show a significant RTV difference of the abutment screw compared to the titanium abutment after dynamic cyclic loading.

• Journal of Biomedical Engineering Research
• /
• v.26 no.2
• /
• pp.123-127
• /
• 2005

Compression Hip Screw (CHS) is one of the most widely-used prostheses for the treatment of intertrochanteric fractures because of its strong fixation capability. Fractures at the neck and screw holes are frequently noted as some of its clinical drawbacks, which warrant more in-depth biomechanical analysis on its design variables. The purpose of this study was to evaluate changes in the strength with respect to the changes in design such as the plate thickness and the number of screw holes. Both mechanical test and FEM analysis were used to systematically investigate the sensitivities of the above-mentioned design variables. For the first part of the mechanical test, CHS (n=20) were tested until failure. The CHS specimens were classified into four groups: Group Ⅰ was the control group with the neck thickness of 6-㎜ and 5 screw holes on the side plate, Group Ⅱ 6-㎜ thick and 8 holes, Group Ⅲ 7.5-㎜ thick and 5 holes, and Group Ⅳ 7.5-㎜ thick and 8 holes. Then, the fatigue test was done for each group by imparting 50% and 75% of the failure loads for one million cycles. For the FEM analysis, FE models were made for each group. Appropriate loading and boundary conditions were applied based on the failure test results. Stresses were assessed. Mechanical test results indicated that the failure strength increased dramatically by 80% with thicker plate. However, the strength remained unchanged or decreased slightly despite the increase in number of holes. These results indicated the higher sensitivity of plate thickness to the implant strength. No fatigue failures were observed which suggested the implant could withstand at least one million cycles of fatigue load regardless of the design changes. Our FEM results also supported the above results by showing a similar trend in stress as those of mechanical test. In summary, our biomechanical results were able to show that plate thickness could be a more important variable in design for reinforcing the strength of CHS than the number of screw holes.

• The Journal of Korean Academy of Prosthodontics
• /
• v.46 no.3
• /
• pp.255-260
• /
• 2008

STATEMENT OF PROBLEM: Preparation of implant beds with lasers is considered a safe and reliable method, but the accuracy of this technique has not been examined. PURPOSE: The purpose of this study was to evaluate the accuracy and effectiveness of implant bed preparation using an Er,Cr:YSGG laser. MATERIAL AND METHODS: An Er,Cr:YSGG laser was applied to pig rib bone. The laser was employed at a 5.75 W power setting, 30 Hz/sec pulse repetition, and 70 ${\mu}s$ pulse duration with 50 % water and 60% air spray. According to laser tips the groups were divided as follows; Group 1: paralleled - shaped sapphire tip (0.6 mm${\Phi}$), Group 2: paralleled - shaped zirconia tip (0.6 mm${\Phi}$), Group 3: tapered sapphire tip (0.4 mm${\Phi}$). The Er,Cr:YSGG laser tip was separated by 1 mm from the bone and applied for 15 seconds in a non-contact mode. After the application, the bone was sectioned for specimens. Histologic measurements were determined by computerized morphometry. The length of the prepared bone surface was measured and the width of the entrance was measured. The results were analyzed with one-way ANOVA (P<0.05). RESULTS: The prepared length of group 3 was longer than that of group 2. The prepared bone width was larger than the width of the laser tip in every group. Additional bone removal was observed adjacent to the prepared area and displayed an irregular surface. CONCLUSION & DISCUSSION: Different cutting effects were observed according to the laser tip, emphasizing the importance of proper tip selection in the clinical setting. This preliminary study supported the existence of hydrokinetic effects.

• The Journal of the Korean dental association
• /
• v.48 no.2
• /
• pp.119-126
• /
• 2010

Introduction. In this study, we applied the immediate loading to implant using temporary prosthesis, and compared the treatment results by each placement site, amongst pre-loading period. The study was intended to search for occurrence of complications and the amount of marginal bone resorption. Materials and Methods. We retrospectively reviewed the medical records of 99 cases of implants from 29 patients who were treated at Seoul National University Bundang Hospital from September 2003 to September 2008. We grouped all the cases by placement arches and pre-loading periods, and subdivided each group by placement site(anterior/posterior), type of prosthesis(full-mouth cross splinting/Partial multiple splinting, Single). Results. In the cases of anterior maxilla, the average amounts of marginal bone resorption showed $1.71{\pm}0.71mm$ in group 1, and $1.44{\pm}0.69mm$ in group 2, which means they revealed no statistically significant difference between group 1 and group 2(p=0.646). In the cases of posterior maxilla, the average amounts of marginal bone resorption showed $1.25{\pm}0.72mm$ in group 1, and $1.14{\pm}1.15mm$ in group 2, which means they were not statistically significant. In the cases of anterior mandible, there was no cases classified as group 4, but the average amounts of marginal bone resorption in group 3 showed $1.38{\pm}0.79mm$. In the cases of posterior mandible, Group 3 showed $1.39{\pm}0.64mm$, and group 4 showed $1.84{\pm}1.19mm$ as amounts of marginal bone resorption, which means they revealed no statistically significant difference between group 3 and group 4(P=0.210). The survival rate of group1 was 97.14%, 92.1% of group3, and 100% of group 2 and group4. According to each type of prosthesis, each average amount of marginal bone resorption revealed no statistically significant difference in maxi11a(p=0.575) in mandible(p=0.206). Conclusion. It is concluded that the marginal bone resorption and the rate of complications might not be affected by placement sites and pre-loading periods. The marginal bone resorption and the rate of complications might vary as different bone quality of placement site and implant system, diameter, length, etc. It is suggested that the proper placement of immediate loading implants decreases the whole treatment period and any inconvenience occurred to patients.

• Journal of Periodontal and Implant Science
• /
• v.33 no.2
• /
• pp.311-319
• /
• 2003

치주조직재생을 도모하기 위한 전통적인 시술방법으로는 여러 가지 골이식재를 이용한 골이식술이 오래 전부터 이용되고 있다. 이번 실험의 목적은 장,단기간의 신생골의 형성과 CPP의 흡수를 비교하여 골이식재로서 Calcium Polyphosphate(CPP)를 평가하는 것이다. 이번 실험에 사용된 CPP는 무수 $Ca(H_2PO_4)$를 condensation하여 무결정의 $Ca(PO_3)_2$를 얻고 이를 용융하고 냉각시킨후 분쇄하여 얻은 것으로 키토산이나 $Na_2O$를 첨가한 후 3세된 비글견에 이식하여 관찰하였다. 양성 대조군으로 동결탈회건조골을 이용하였다. 조직학적으로 3개월 소견과 같이 섬유조직의 게재없이 신생골의 형성이 관찰되었다. 12개월 후의 신생골의 형성은 3개월 결과에 비해서 동결탈회건조골이나 키토산, $Na_2O$를 넣은 CPP 과립에서 더 많은 비율로 나타났다. 음성 대조군과 이식재를 넣은 군간에는 유의성이 있는 것으로 나타났고(p<0.05), 또한 키토산을 첨가한 CPP 과립과 $Na_2O$를 첨가한 CPP 과립 사이에는 신생골의 형성에 유의성이 없었다. 이식한 CPP 과립의 경우 흡수소견이 3개월 결과에 비해 크게 증가하지 않았다. 이번 실험에서는 첨가물에 상관없이 CPP 과립은 골유도성과 생체적합성을 보였다. 그러나 흡수속도가 매우 느려 신생골로 대체되는 여부를 알 수 없었다. 향후 연구에서는 흡수속도를 증가시킬 수 있는 적당한 CPP 형태와 첨가물을 밝혀내어야 할 것이다.

• Clinics in Shoulder and Elbow
• /
• v.14 no.1
• /
• pp.140-145
• /
• 2011

Purpose: Installing a radial head prosthesis has developed into a reliable procedure to replace the native radial head for treating unreconstructible radial head fracture when this is associated with an unstable elbow or forearm. A variety of implants have been developed and these are now commercially available. This article reviews the literature related to the indications, the available implants and the surgical techniques of radial head replacement arthroplasty. Materials and Methods: The main indication for a metallic radial head prosthesis is a comminuted fracture that is not amenable to reconstruction, and particularly if it is associated with complex elbow injuries. Excision of the radial head should be avoided in the presence of combined injured ligaments or interosseous membrane injury. Three different implants are available in Korea, including the bipolar, press fit monopolar and loose fit monopolar radial head prostheses. A primary technical goal of radial head arthroplasty is the insertion of an implant that closely replicates the native radial head. The major pitfall when using a metallic radial head prosthesis is the insertion of a longer implant, which results in overstuffing of the radiocapitellar joint. Results and Conclusion: Satisfactory clinical results can be anticipated when a radial head prosthesis is used for the correct indications and when a systemic approach is undertaken to ensure proper sizing. For the future studies, we need data regarding the long term outcomes and comparison of the various types of prostheses.