• 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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권4호
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• pp.302-309
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• 2002

In order to improve the success rate of implants, various implant designs have been developed. Although there have been enough efforts to handle the surface of the implant with careful choice of material and mechanics so that the bone and the implant can be tightly joined together, they have still failed to play the role of periodontal ligaments of the natural teeth in the past. The role of periodontal ligaments is very important since it can improve the initial stability of implant by absorbing the impacts. The purpose of this study is, thus, to test the possibility of alleviating the impact when the surface of the implant was coated with chitosan, a natural polymer, and making sure that the coated material stayed on. Then, the condition of newly developed bone formation and the degree of inflammation in response was closely observed in the surface level. In the main experiment, Chitosan coated implant ($3.3mm{\times}7mm$) was implanted on both the right and the left side of rabbit's femur. The animals were each sacrificed on the $1^{st}$, $2^{nd}$, $3^{rd}$, $7^{th}$, $14^{th}$, $21^{st}$ and 28th day. The process was observed under an light microscope after the Toluidin Blue staining. From the experiment, it was found that the chitosan was evenly distributed on the surface of the screws, and the implant was adjoined with adjacent bone. There was a sign of inflammation on the $3^{rd}$ day, but on the $14^{th}$ day, the formation of woven bone and newly formed bones were noticed. Also, chitosan filled the gap was formed between the implant and the newly formed bone. The implant, the chitosan and the newly formed bone were forming one unit as a result. Therefore, it was found that chitosan coated implant could absorbe the impact in the initial stage of implant.

• The Journal of Advanced Prosthodontics
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• 제7권2호
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• pp.151-159
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• 2015

PURPOSE. To describe and characterize the surface topography and cleanliness of CAD/CAM manufactured zirconia abutments after steaming and ultrasonic cleaning. MATERIALS AND METHODS. A total of 12 ceramic CAD/CAM implant abutments of various manufacturers were produced and randomly divided into two groups of six samples each (control and test group). Four two-piece hybrid abutments and two one-piece abutments made of zirconium-dioxide were assessed per each group. In the control group, cleaning by steam was performed. The test group underwent an ultrasonic cleaning procedure with acetone, ethyl alcohol and antibacterial solution. Groups were subjected to scanning electron microscope (SEM) analysis and Energy-dispersive X-ray spectroscopy (EDX) to verify and characterize contaminant chemical characterization non- quantitatively. RESULTS. All zirconia CAD/CAM abutments in the present study displayed production-induced wear particles, debris as well as organic and inorganic contaminants. The abutments of the test group showed reduction of surface contamination after undergoing an ultrasonic cleaning procedure. However, an absolute removal of pollutants could not be achieved. CONCLUSION. The presence of debris on the transmucosal surface of CAD/CAM zirconia abutments of various manufacturers was confirmed. Within the limits of the study design, the results suggest that a defined ultrasonic cleaning process can be advantageously employed to reduce such debris, thus, supposedly enhancing soft tissue healing. Although the adverse long-term influence of abutment contamination on the biological stability of peri-implant tissues has been evidenced, a standardized and validated polishing and cleaning protocol still has to be implemented.

• 대한치과보철학회지
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• 제39권6호
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• pp.659-681
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• 2001

Platelet-rich plasma(PRP) has been known to increase the rate and degree of bone formation by virtue of growth factors in concentrated platelets. Although its great healing effect on bone defect or pre-implantation site preparation in conjunction with bone substitute has been reported, the effect associated with implant is unknown. The purpose of this study was to investigate the effect of PRP on rapid osseointegration of endosseous dental implants in the rabbit tibiae. Twenty two adult female New Zealand white rabbits, weighing approximately 2.7-3.3kg, were used for this study. Twelve of the 22 animals were used for histomorphometric analysis and ten of the 22 were for removal torque test. Each animal received two implants in each tibia (two treated with PRP and two as control) and was given fluorochrome intramuscularly. For histomorphometric analysis, rabbits were divided into four groups according to the healing period. At 1 week, 2 weeks, 4 weeks and 8 weeks postoperatively, each three animals were sacrificed serially and the amount and rate of bone formation around dental implant were examined on the undecalcified sections under fluorescent microscope, polarized microscope and light microscope connected to a personal computer equipped with image analysis system. For removal torque test, rabbits were divided into two groups and removal torque tests were performed at 4 weeks, 10 weeks after implant placement. In total, 88 screw shaped, commercially pure titanium implants (Neoplant, Neobiotech, Seoul, Korea) were used in this study. Labeling pattern reflected differences of two groups in bone formation rate at each period. Histomorphometrically, PRP group showed significantly higher bone volume within threads compared to control group at 2 weeks ($70.30{\pm}4.96%$ vs. $50.68{\pm}6.33%$; P < .01) and 4 weeks ($82.59{\pm}5.94%$ vs. $72.94{\pm}4.57%$; P < .05 ). PRP group at 1, 2 and 4 weeks revealed similar degree of bone volume formation comparable to control group at 2, 4 and 8 weeks, respectively. On the other hand, while PRP group showed higher bone-implant contact ($47.37{\pm}8.09%$) than control group ($33.16{\pm}13.47%$) at 2 weeks, there were no significant differences between PRP group and control group for any experimental period. Removal torque values also showed no significant differences between PRP group and control group at any experimental period (P > .05). These findings imply that PRP could induce rapid, more bone formation around implant during early healing period and get faster secondary stability for reducing healing period, though it has not induced bone maturation enough to resist functional loading.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권4호
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• pp.225-231
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• 2022

Objectives: This study aims to evaluate the efficacy and safety of two types of sandblasted with large-grit and acid-etched (SLA) surface implants with different surface roughness. Patients and Methods: This study was conducted based on a clinical record review of 55 patients (mean age, 53.00 years). A total of 80 SLA surface implants was placed. Among the 80 implants, 38 implants placed in 29 subjects had surface roughness (Ra) of 3.09 ㎛ (test group, TG), while the other 42 implants placed in 31 subjects had a surface roughness (Ra) of 2.50 ㎛ (control group, CG). A comparison was made of implant primary/secondary stability; success and survival rates; marginal bone loss; and soft tissue assessment including probing pocket depth (PPD), plaque index (PI), gingival index (GI), and bleeding on probing (BOP) between the groups at 1 year after implant placement. Results: Among the implants that were initially registered, 1 from the TG and 4 from the CG dropped out, leaving 37 implants in the TG and 38 implants in the CG to be traced and analyzed. Although 1 TG case showed unstable primary stability, all cases showed stable secondary stability. Success and survival rates at 1 year after implant placement were 100% in both groups. Marginal bone loss was 0.07 mm and 0.00 mm for the TG and CG, respectively, but the difference was not significant. Among the several parameters for evaluation of soft tissue, the TG showed lower PI at 1 year after implant placement (TG=0.00, CG=0.29; P=0.0004), while the remaining categories showed no significant difference between the groups. Conclusion: This study shows that the two types of SLA implants with different surface roughness have no difference in efficacy or safety. Therefore, both of the implants can be used safely and with promising outcomes.

• 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.

• Journal of Periodontal and Implant Science
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• 제47권1호
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• pp.51-63
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• 2017

Purpose: Following tooth extraction, alveolar ridge preservation (ARP) can maintain the dimensions of ridge height and width. Although previous studies have demonstrated the effects of ARP, few if any studies have investigated the compressive force applied during grafting. The aim of this study was to determine the effects of different compressive forces on the graft materials during ARP. Methods: After tooth extraction, sockets were filled with deproteinized bovine bone mineral with 10% porcine collagen and covered by a resorbable collagen membrane in a double-layered fashion. The graft materials were compressed using a force of 5 N in the test group (n=12) and a force of 30 N in the control group (n=12). A hidden X suture was performed to secure the graft without primary closure. Cone-beam computed tomography (CBCT) was performed immediately after grafting and 4 months later, just before implant surgery. Tissue samples were retrieved using a trephine bur from the grafted sites during implant surgery for histologic and histomorphometric evaluations. Periotest values (PTVs) were measured to assess the initial stability of the dental implants. Results: Four patients dropped out from the control group and 20 patients finished the study. Both groups healed without any complications. The CBCT measurements showed that the ridge volume was comparably preserved vertically and horizontally in both groups (P>0.05). Histomorphometric analysis demonstrated that the ratio of new bone formation was significantly greater in the test group (P<0.05). The PTVs showed no significant differences between the 2 groups (P>0.05). Conclusions: The application of a greater compressive force on biomaterials during ARP significantly enhanced new bone formation while preserving the horizontal and vertical dimensions of the alveolar ridge. Further studies are required to identity the optimal compressive force for ARP.

• 구강회복응용과학지
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• 제27권3호
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• pp.267-275
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• 2011

구치부 부분 결손 환자에서 즉시하중군과 지연하중군의 임상적 성공률을 측정하기 위한 전향적 연구가 계획되었다. 즉시하중군에서는 17명의 환자에 42개의 GSIII 임플란트(Osstem, Korea)를 식립하고 48시간 안에 하중을 가하였다. 대조군인 지연하중군에서는 15명의 환자에 27개의 GSIII 임플란트를 식립하고 평균 $2.6{\pm}1.7$개월 후에 하중을 가하였다. 하중 전 1차안정성을 ISQ로 측정하였고 임상증상, 동요도, 연조직 반응을 식립 직후, 3개월 후, 6개월 후, 12개월 후에 평가하였다. 변연골 흡수량은 치근단 방사선 영상으로 측정하였고 Mann-Whitney test (${\alpha}$=0.05)와 repeated measured ANOVA (${\alpha}$=0.05)로 두 군의 차이를 검정하였다. 식립 직후 실험군과 대조군의 ISQ는 각각 $80.3{\pm}7.1$과 $69{\pm}17$이었다. 실험군은 95.23%의 성공률을, 대조군은 100% 성공률을 나타냈다. 3개월과 6개월 후 실험군의 변연골 흡수량은 대조군에 비해 유의성 있게 컸다(p<0.05). 하지만 12개월 후 두 군의 차이는 관찰되지 않았다 (p>0.05). 변연골 흡수량은 성별과 식립위치에 따른 차이가 없었다 (p>0.05). 실험의 한계 내에서, 1차안정성이 획득된다면 구치부 식립 GSIII 임플란트의 즉시하중은 예지성 있는 치료법이라고 여겨진다.

• Imaging Science in Dentistry
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• 제40권4호
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• pp.179-185
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• 2010

Purpose : Cortical bone thickness is one of the important factor in mini-implant stability. This study was performed to investigate the buccal cortical bone thickness at every interdental area as an aid in planning mini-implant placement. Materials and Methods : Two-dimensional slices at every interdental area were selected from the cone-beam computed tomography scans of 20 patients in third decade. Buccal cortical bone thickness was measured at 2, 4, and 6 mm levels from the alveolar crest in the interdental bones of posterior regions of both jaws using the plot profile function of $Ez3D2009^{TM}$ (Vatech, Yongin, Korea). The results were analyzed using by Mann-Whitney test. Results : Buccal cortical bone was thicker in the mandible than in the maxilla. The thickness increased with further distance from the alveolar crest in the maxilla and with coming from the posterior to anterior region in the mandible (p<0.01). The maximum CT value showed an increasing tendency with further distance from the alveolar crest and with coming from posterior to anterior region in both jaws. Conclusion : Interdental buccal cortical bone thickness varied in both jaws, however our study showed a distinct tendency. We expect that these results could be helpful for the selection and preparation of mini-implant sites.

• Clinics in Orthopedic Surgery
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• 제10권4호
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• pp.491-499
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• 2018

Background: Advances in surgical techniques, implant technology, radiotherapy, and chemotherapy have increased the recovery chances of patients with bone sarcomas. Accordingly, patients' expectations on life quality have also increased, highlighting the importance of objective evaluation of the functional results of reconstruction. Methods: Thirteen patients with distal femoral endoprosthesis, who had been followed for an average of 2.9 years were evaluated. Postural stability, daily energy expenditure, muscle power, and range of motion were the four parameters analyzed in this study. The Musculoskeletal Tumor Society (MSTS) score and Toronto Extremity Salvage Score (TESS) were used to assess postoperative function and examine correlations with other parameters. Results: Patients had sedentary activities in 84% of their daily lives. They exhibited a slower speed in the walk across test and a higher sway velocity in the sit-to-stand test (p = 0.005). MSTS scores were significantly correlated with the daily energy expenditure and walking speed. Conclusions: Objective functional results acquired from various clinics will provide significant data to compare reconstruction techniques, rehabilitation protocols, and surgical techniques. In this way, it will be possible to satisfy the expectations of patients that increase in relation to enhanced recovery.