• Journal of Periodontal and Implant Science
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• 제48권3호
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• pp.182-192
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• 2018

Purpose: The purpose of the present study was to validate an experimental model for assessing tissue integration of titanium and zirconia implants with and without buccal dehiscence defects. Methods: In 3 dogs, 5 implants were randomly placed on both sides of the mandibles: 1) Z1: a zirconia implant (modified surface) within the bony housing, 2) Z2: a zirconia implant (standard surface) within the bony housing, 3) T: a titanium implant within the bony housing, 4) Z1_D: a Z1 implant placed with a buccal bone dehiscence defect (3 mm), and 5) T_D: a titanium implant placed with a buccal bone dehiscence defect (3 mm). The healing times were 2 weeks (one side of the mandible) and 6 weeks (the opposite side). Results: The dimensions of the peri-implant soft tissue varied depending on the implant and the healing time. The level of the mucosal margin was located more apically at 6 weeks than at 2 weeks in all groups, except group T. The presence of a buccal dehiscence defect did not result in a decrease in the overall soft tissue dimensions between 2 and 6 weeks ($4.80{\pm}1.31$ and 4.3 mm in group Z1_D, and $4.47{\pm}1.06$ and $4.5{\pm}1.37mm$ in group T_D, respectively). The bone-to-implant contact (BIC) values were highest in group Z1 at both time points ($34.15%{\pm}21.23%$ at 2 weeks, $84.08%{\pm}1.33%$ at 6 weeks). The buccal dehiscence defects in groups Z1_D and T_D showed no further bone loss at 6 weeks compared to 2 weeks. Conclusions: The modified surface of Z1 demonstrated higher BIC values than the surface of Z2. There were minimal differences in the mucosal margin between 2 and 6 weeks in the presence of a dehiscence defect. The present model can serve as a useful tool for studying peri-implant dehiscence defects at the hard and soft tissue levels.

• 대한치과보철학회지
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• 제44권5호
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• pp.594-605
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• 2006

Statement of problem: Modification of titanium implant surface has potential to ensure clinically favorable performance that several surface modification technologies have been introduced. Among the methods. anodizing method and sol-gel hydroxyapatite coating method have gained much interest due to its roughness and chemical composition of the coating layer, but more of its biocompatibility result is required. Purpose : The purpose of this study was to compare bone-implant interface shear strength of four different surface treated implants as time elapsed. Resonance frequency analysis(RFA) and removal torque measurement methods were employed to measure implant stability at one week and six week after implantation. Material and method: A total of 80 screw-shaped implant [20 machined, 20 resorbable media blasted(RBM), 20 anodized, and 20 anodized+hydroxyapatite sol-gel coated] were prepared, and one of each group was implanted in the tibia of a New Zealand white rabbit that total 20 of them were used. In order to test the implant stability and implant-tissue interface contact changing in the bone bed, each 10 rabbit were sacrificed 1 week and 6 week later while resonance frequency and removal torque were measured. One-way analysis of variance and the Tukey test were used for statistical analysis. Results : The results were as follows. 1. There was no statistically significant difference of implant stability quotients(ISQ) value in RFA between individual groups after 1 week of implantation and 6 weeks(p>0.05). But, there was statistically significant increase of ISQ value in 6 weeks group compared to 1 week group(p<0.05). 2. There was no statistically significant difference in removal torque analysis between individual groups after 1 week of implantation and 6 weeks(p>0.05). but there was statistically significant increase in all 4 groups after 6 weeks compared to 1 week later(p<0.05). 3. There was no statistically significant difference in removal torque analysis between anodized group and HA coating after anodic oxidation 6 weeks later(p>0.05), but significant difference was appeared in both groups compared to RBM group and smooth-machined group(p<0.05). Conclusions : It can be suggested that changes in surface characteristics affect bone reactions. Anodized and anodized+hydroxyapatite sol-gel coating showed significantly improved bone tissue response to implants, but further study on the effect of hydroxyapatite dissolution is needed.

• 대한치과보철학회지
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• 제44권5호
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• pp.606-616
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• 2006

Purpose: This experiment examined the effect of different surface treatment on the osseointegration and stability of implants. Material and methods: In this study, 40 each of machined, SLA and RBM implants, which are the most commonly used implants, were implanted into the tibia of 20 normal rabbits using $OsseoCare^{TM}$. The rabbits were sacrificed after 1 week, 4 weeks, 8 weeks and 12 weeks for implant stability analysis, removal torque analysis, histologic and histomorphometric analysis. Result : ISQ showed significant difference between Machined and RBM at first week and at 4 weeks. There was significant difference between Machined and both SLA and RBM(p<0.05) but after 8 weeks there were no significant difference between each group. In the removal torque, RBM showd significantly higher values than SLA and Machined surface at 1st week. At 4th and 12th week, there was significant difference between Machined and SLA, RBM(p<0.05). In the bone to implant contact variable, there was no significant difference between each surface treatment method. In the Machined surface group, there was no significant difference between each time interval. but in SLA group, there were significant differences between the 1st week and 12th week and in RBM group, there were significant differences between the 1st week and 8th, 12th week and between 4th and 12th week(p<0.05). The bone area showed significantly higher values in SLA and RBM compared to Machined surface 1st and 8th week and significantly higher values in SLA than Machined surface at the 4th week(p<0.05). Conclusion: The roughened surface of implants showed positive effect in the early stages of implantation and assisted in bone formation After the bone formation stage, there was no statistical difference between Machined and roughened surface groups. In dental implantation, where initial stability is critical to the success of implants, the use of roughened surface implants should assist in reducing the healing period after implantation.

• Journal of Periodontal and Implant Science
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• 제36권3호
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• pp.673-682
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• 2006

Recent study shows that implant design has a great impact on initial stability in bone. The ITI $TE^{(R)}$ implant, designed originally for immediate placement has a tapered/ cylindrical form which fits the anatomical shape of the natural alvelous or tooth root. The increased diameter at the collar region coupled with more threads lead to more bone contact and enhanced stability. The aim of this retrospective study is to evaluate the clinical use and the efficacy of recently introduced ITI TE implant with a new macro-design. The following results are compiled from 139 patients who received ITl TE implant surgery at the periodontal department. of Yonsei University Hospital between July 2002 and September 2005. 1. 139 patients received 173 ITl $TE^{(R)}$ implants in their maxilla and mandible (Mx 82, Mn 91). Posterior area accounted for 84% of the whole implant surgery, 2. In the distribution of bone quality, type III(41,0%) was the most, followed by type IV(41,0%) and type II (27.7%). As for the bone quantity, type B(43.9%) was the most, followed by type C(42.2%), type D(12.2%) and type A(1.7%). 3. 125 implants(83.9%) were treated by single crown, which accounted for the majority. 4, The total implant survival rate was 100% after a mean follow-up period of 21.2 months. This preliminary data with ITl $TE^{(R)}$ implant showed excellent survival rate although the majority of implants evaluated in this study were placed in the posterior region of the jaw and compromised sites.

• 대한치과보철학회지
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• 제30권4호
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• pp.541-564
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• 1992

The purpose of this experiment was to study the effect of implantation of the dense hydroxyapatite (HA) granules$(Apaceram^{(R)})$ in the fresh extraction sockets on the residual ridge resorption in normal and induced diabetic rabbits. Sixty-four white rabbits, weighing 3.0kg, were utilized in this study and they were divided into four group : group 1-sixteen normal rabbits without filling HA granules, group 2-sixteen normal rabbits with filling HA granules, group 3-sixteen diabetic rabbits without filling HA granules, group 4-sixteen diabetic rabbits with filling HA granules. HA granules were filled immediately after extraction in the extraction sockets of the mandibular left 1st, 2nd, and 3rd molar in group 2 and 4, and no HA granules were filled in group 1 and 3. The calculation of residual ridge resoption was done at 4th week, 8th week, 12th week, and 16th week after surgery, and histologic examination was performed to study healing process at 2nd week, 4th week, 8th week, and 16th week after surgery. The results were as follows : 1. The amount of residual ridge resorption was largest in group 3, and smallest in group 2 in every interval. There was no statistically significant difference between group 1 and 4. 2. In all groups, the amount of residual ridge resorption was high until 4th week after surgery, but the rate of residual ridge resolution slowly decreased after 4th week 3. There was more active healing process in group 1 and 2 than in group 2 and 4. 4. According to filling of HA granules, there was no difference in the amount of new bone formation, but direct contact could be observed between newly formed bone and HA granules in group 2 and 4. 5. Group 1 and 3 showed marked bone resorption and adipose marrow from 8th-16th week after surgery, but group 2 and 4 did not show maeked bone resolution, and showed fibrous tissue and a little adipose tissue among trabeculae from 8th week.

• 대한치과보철학회지
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• 제58권2호
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• pp.77-85
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• 2020

목적: N-acetyl cysteine (NAC)를 탑재한 sandblasted and large-grit and acid-etched (SLA) 임플란트를 성견에 식립한 후, 조직형태학적 분석을 통하여 NAC가 SLA 임플란트 주위의 초기 골형성에 미치는 영향을 알아보고자 한다. 재료 및 방법: NAC 탑재 여부에 따라 2개의 실험군으로 구성하였으며, SI 군은 NAC를 탑재하지 않은 SLA 임플란트로, NSI 군은 NAC를 탑재한 SLA 임플란트로 설정하였다. 4마리의 성체 비글 견에 두 실험군의 임플란트를 식립하고(각 군당 n = 8) 술 후 3주와 6주에 각각 2마리의 비글 견을 희생하여 식립된 임플란트 매식체와 주위 골 조직을 채취하였다. 조직 표본을 제작하고 조직형태학적 검사를 통해 골-임플란트 접촉률 및 골면적비율을 계산하였다. NAC 탑재 여부에 따른 각 실험군간 골-임플란트 접촉률과 골면적비율의 유의성을 알아보기 위해 독립표본 t검정을 이용한 통계분석을 시행하였다(α = .05). 결과: 3주차의 경우 NAC를 탑재한 SLA 임플란트가 일반 SLA 임플란트보다 약 1.5배 높은 골-임플란트 접촉률을 보였으나 통계적 유의성은 없었다(51.79 vs 35.43%; P = .185). 골면적 비율에서는 NAC를 탑재한 SLA 임플란트가 일반 SLA 임플란트보다 통계적으로 유의성 있게 높은 결과 값을 보였다(45.09 vs 37.57 %; P = .044). 6주차의 경우 골-임플란트 접촉률과 골면적 비율 모두에서 NAC를 탑재한 SLA 임플란트와 일반 SLA 임플란트가 비슷한 결과 값을 보였다(P > .05). 결론: 본 실험의 한계 내에서 NAC는 SLA 임플란트 주위의 초기 골형성에 긍정적인 영향을 미침으로써 임플란트의 골유착기간을 단축시키고 하중 부담시기를 앞당기는 데에 기여할 것이라고 사료된다.

• 구강회복응용과학지
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• 제24권4호
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• pp.337-349
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• 2008

최적의 골유착을 얻기 위하여 임플란트 디자인의 개선과 다양한 표면처리 방법이 개발되어 왔는데, 특히 최근 알칼리 에칭과 이온 주입법, 양극산화법 등 생화학적인 골유착을 유도할 수 있는 표면개질 방법이 관심의 대상이 되고 있다. 이러한 방법 중 마그네슘 이온을 함유한 전해액속에서 양극산화피막처리한 임플란트(마그네슘 임플란트)를 이용하여 조기 하중의 가능성이 제시된 바 있다. 그러나 마그네슘 임플란트의 경우 장기간의 기능적 하중을 가한 경우에 대한 연구가 부족한 상태이므로, 이에 본 연구에서는 비글견을 이용한 동물실험을 통해 지연하중을 가한 마그네슘 임플란트의 방사선적, 임상 안정성 검사 및 조직형태학적 분석을 시행하여 화학적 표면개질 임플란트의 골조직 반응을 기계가공 임플란트와 비교 평가하고자 하였다. 발치 후 3개월의 치유과정을 가진 비글 성견 6마리의 하악에 좌우 3개씩 실험용으로 제작된 직경 3.75 mm, 길이 10.0 mm의 나사 형태 임플란트 36개를 보편적인 임플란트 시술시 이용하는 식립법을 이용하여 식립하였다. 18개의 대조군은 기계가공만 한 상태였고, 실험군은 마그네슘을 함유한 전해액에서 양극산화 피막처리하였다. 식립 후 3개월 동안의 치유기간 후 이차수술을 실시하였으며, 연결고정하지 않고 단일치 금관수복으로 보철물을 장착하여 하중을 가하였다. 3개월 동안 하중을 가한 후에 희생시켜 비탈회 연마 표본을 제작하여 조직형태 계측학적 분석을 시행하였다. 임플란트 식립시, 이차 수술시, 하중을 가한 1개월, 3개월 후에 변연골 흡수를 평가하기 위해 방사선학적 검사를 실시하였고, 골계면 사이에서의 안정성을 평가하기 위해 공진주파수 수치를 측정하였다. Mann-Whitney U test와 repeated measured ANOVA를 이용하여 95 퍼센트 유의수준으로 통계적 유의성을 확인하였다. 총 36개의 임플란트 중 8개에서 일차 수술 후 골유착의 실패가 나타났으며, 1개는 3개월의 부하 후에 실패 양상이 나타났다. 공진주파수분석결과, 마그네슘 임플란트군은 대조군과는 달리 공진주파수 수치가 증가하다가 다소 감소하는 양상을 보였으며, 하중을 가한 3개월 후에는 두 군의 수치가 비슷하였다. 방사선 사진 분석 결과 두 군 모두 시간에 따른 변연골 흡수량이 증가하였으며, 통계적으로 유의한 차이는 없었다. 조직형태학적인 분석 결과 마그네슘-임플란트가 대조군에 비해 더 높은 수치의 골임플란트 계면접촉율을 보여 주었으나, 나사산내 골면적은 더 낮았다. 그러나 두 군 모두에서 통계적 유의성은 없었다. 이상의 결과에서 지연 하중을 가하는 경우에 있어서 골유착에 대한 마그네슘-임플란트의 효과는 기계가공된 임플란트와 유사하였다. 조기 하중시 더 빠르고 강한 골반응을 보여주던 이전 연구와 종합하여 볼 때, 마그네슘 임플란트는 즉시 또는 조기 하중 가능성을 증진시켜 주며, 지연 하중에서는 생체 적합성이 우수한 타이타늄과 유사한 골유착 정도를 보이는 것으로 사료된다. 그러나 임상적으로 화학적 표면개질 방법의 유용성을 판단하기 위해 다양하고 장기적인 임상 연구가 필요하리라 사료된다.

• 대한치과보철학회지
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• 제29권3호
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• pp.141-170
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• 1991

This study was to analyze the displacement and the magnitude and mode of distribution of the stresses in the lower overdenture, the mucous membrane, the abutment teeth and the mandibular supporting bone when various abutment designs were subjected to different loading schemes. For this study, the two-dimensional finite element method was used. The models of overdenture and mandibe with the canine and the second premolar remaining, were fabricated. In the first design, a 1 mm space was prepared between the denture and the dome abutment with the height of 2 mm(OS). In the second design, a contact between the denture and the occlusal third of the dome abutment with the hight of 2 mm was prepared(OC). In the third design, a 0.5 mm space was prepared between the denture and 8 degree tapered cylindrical abutments with the height of 7 mm(TS). In the fourth design, a contact between the denture and the occlusal two thirds of the conical abutments with the height of 7 mm was prepared(TC). In order to represent the same physiological condition as the fixed areas of the mandible under loading schemes, the eight nodes which lie at the mandibular angle, the coronoid process and the mandibular condyle were assumed to be fixed. Each model was loaded with a magnitude of 10 Kgs on the first molar region (P1) and 7 Kgs on the central incisor region (P2) in a vertical direction. The force of 10 Kgs was then applied distributively from the first premolar to the second molar of each motel in a vertical direction (P3). The results were as follows: 1. The vertical load on the central incisor region(P2) produced the higher displacement and stress concentration than that on the posterior region(P1, P3). 2. The case of space between abutment and denture base produced higher displacement than that of contact, and the case of long abutment produced higher displacement than that of short abutment because of low rigidity of denture base. 3. The magnitude of the torque and vertical force to the abutment teeth and the stress distribution to the denture base was higher in the telescope coping than in the overdenture coping. 4. The vertical load on the central incisor region(P2) produced higher equivalent stress in the mandible than that on the posterior region(P1, P3). 5. The case of space between abutment and denture base produced better stress distribution to the farther abutment from the loading point than that of contact. 6. In case of sound abutment teeth, the type of telescope coping can be used, hilt in case of weak abutment, the type of overdenture coping is considered to be favorable generally.

• 대한치과교정학회지
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• 제29권6호
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• pp.637-648
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• 1999

교정 치료 후 이상적인 교합과 양호한 심미적 결과를 얻기 위해서 일반적으로 교정 장치 제거하기 4개월에서 7개월 전에 detailing을 시행한다. 이와 같은 과정을 finishing이라고 하며, 이 과정은 최종적인 양호한 결과를 얻는데 있어서 필수적이다. 일부 교정의는 finishing을 위한 특별한 이론적 근거 및 기준 없이 이 과정을 교정 치료의 마지막 단계에서 시행하면 되는 것으로 여기고 있다. 그러나, 최종적인 양호한 교정 치료 결과를 얻기 위해서는finishing 과정이 총 치료 계획의 부분으로 치료의 초기 단계에서부터 고려되어야만 하며, 교정 장치 제거를 위한 이론적 근거 및 기준에 근거한 finishing을 위한 checklist가 필요하다. 이 checklist는 크게 네 부류로 분류할 수 있다. 즉, 교합 요인, 심미적 요인, 치주적 요인과 습관적 요인으로 분류할 수 있다. 교합 요인에서 점검해야할 요소로는 alignment, marginal ridge discrepancy, interproximal contact, anterior inclination, posterior inclination, overjet, overbite, arch form과 functional occlusion 등이 있다. 심미적 요인에는 gingival form, crown form, crown width과 crown length 등이 있다. 치주적 요인에는 root angulation, bone level 등이 있다. 습관적 요인에는 mouth breathing, tongue position at rest, tongue thrust habit, lip biting, nail biting과 finger sucking 등이 있다.

• Journal of Periodontal and Implant Science
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• 제43권1호
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• pp.41-46
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• 2013

Purpose: The objective of this study was to evaluate the effect of microthreads on removal torque and bone-to-implant contact (BIC). Methods: Twelve miniature pigs for each experiment, a total of 24 animals, were used. In the removal torque analysis, each animal received 2 types of implants in each tibia, which were treated with sandblasting and acid etching but with or without microthreads at the marginal portion. The animals were sacrificed after 4, 8, or 12 weeks of healing. Each subgroup consisted of 4 animals, and the tibias were extracted and removal torque was measured. In the BIC analysis, each animal received 3 types of implants. Two types of implants were used for the removal torque test and another type of implant served as the control. The BIC experiment was conducted in the mandible of the animals. The $P_1-M_1$ teeth were extracted, and after a 4-month healing period, 3 each of the 2 types of implants were placed, with one type on each side of the mandible, for a total of 6 implants per animal. The animals were sacrificed after a 2-, 4-, or 8-week healing period. Each subgroup consisted of 4 animals. The mandibles were extracted, specimens were processed, and BIC was analyzed. Results: No significant difference in removal torque value or BIC was found between implants with and without microthreads. The removal torque value increased between 4 and 8 weeks of healing for both types of implants, but there was no significant difference between 8 and 12 weeks. The percentage of BIC increased between 2 and 4 weeks for all types of implants, but there was no significant difference between 4 and 8 weeks. Conclusions: The existence of microthreads was not a significant factor in mechanical and histological stability.