• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.1039-1052
• /
• 2005

IMZ는 "intramobile cylinder implant system" (IMZ)로 독일에서 가장 오래되고 많이 사용되어진 임플란트 중 하나이다. 이 임플란트에 관한 장기적 성공률과 생존률에 대한 연구는 대개 80% 이상을 보고하고 있다. 그러나, 연세대학교 치과병원 치주과에서 식립된 83개의 임플란트에서는 이전의 연구와는 다른 결과를 나타내었다. 1. IMZ 임플란트의 생존률은 67.5% 였다. 2. 변연 치조골 소실에 대한 성공 기준을 적용한 결과 성공률은 49.4%로 나타났다. 3. 발거된 총 27개의 임플란트 중에서 임플란트 주위 골소실을 가지는 경우는 17개, 내부구조 파절은 4개, 식립체 파절은 5개로 보고되었다. 4. 10년 이상 생존된 임플란트에서 변연골 소실의 평균치는 2.82mm였다. IMZ 임플란트는 장기적으로 높은 실패율을 보고하였다. 이는 cylindrical design, titanium plasma flame spray coating, prosthodontic complication 등의 요소에 기인한 것으로 사료된다. 임플란트는 그 형태, 표면 처리 등 여러 가지 요인들에 의해 실패가 나타날 수 있으며 본 연구를 통해 임플란트의 개발 및 선택에 바탕이 될 수 있을 것으로 생각된다.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.29 no.2
• /
• pp.153-162
• /
• 2013

This study compared the marginal bone loss around dental implants that were placed in the canine areas of the mandibles and finded the survival rate of the implants, marginal bone loss around implants and prosthetic complications in 20 patients treated with overdentures retained with Locator attachments. Implants placed in this study showed a 95% survival rate and the average marginal bone loss was 1.21 mm($SD{\pm}0.60mm$) in 94.3 weeks of functional loading. Implant-retained overdentures had various prosthetic complications such as male change, metal cap loosening, Locator attachment loosening, denture teeth change, relining and denture fracture. Implant-retained overdentures using two implants and Locator attachments in the edentulous mandibles is considered as a stable way for long terms because of minimal invasive operation, simple prosthetic process and easy repair.

• Korean Journal of Clinical Laboratory Science
• /
• v.47 no.3
• /
• pp.117-124
• /
• 2015

Mesenchymal stem cells (MSCs) are an attractive tool in tissue engineering as they have the required potential to treat injured articular cartilage. UV-exposed DTOPV (S-triazine bridged p-phenylene vinylene) is a biocompatible and fluorescent polymer with a hydrophilic surface. Previous studies have demonstrated that the surface wettability and hydrophilicity play critical roles in regulating cell adhesion and proliferation. The objective of this study was to improve the potential of in vitro MSC differentiation into Chondrocytes using DTOPV. MSCs were cultured on two different substrates: (1) tissue culture polystyrene (TCPS) as a reference and (2) UV-exposed and patterned DTOPV films. Chondrogenesis of MSCs was induced for two weeks on TCPS and DTOPV in the presence of an induction medium containing transforming growth factor (TGF)-${\beta}3$. Interestingly, the MSCs on TCPS adhered and spread, while those on DTOPV tended to form aggregates within several days. The cells cultured on DTOPV for two weeks had a round morphology, with stronger Safranine O staining of the extracellular matrix than that of the cells cultured on TCPS. Also, Type II collagen gene was significantly expressed in cells induced on DTOPV. These results indicate that chondrogenic differentiation of MSCs proceeds more rapidly on DTOPV than on TCPS. Therefore, in cartilage tissue engineering, DTOPV could be used to induce effective chondrogenic differentiation of MSCs.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.27 no.3
• /
• pp.267-275
• /
• 2011

This prospective study was designed to compare clinical outcomes of immediately loaded implant with delayed loaded implant in partially posterior edentulous patients. For test group, 42 GS III (Osstem, Korea) implants in 17 patients were loaded within 48 hours after the placement. Control group was 27 implants in 15 patients loaded at $2.6{\pm}1.7months$ from the placement surgery. Before loading, primary stability was evaluated by ISQ value. Clinical symptoms, mobility, soft tissue state was evaluated at baseline, 3 months, 6 months and 12 months of loading. Marginal bone level change was also measured with periapical radiographs. Mann-Whitney test (${\alpha}$=0.05) and repeated measured ANOVA (${\alpha}$=0.05) was used for marginal bone level change between two groups. At the baseline, mean ISQ value of test group and control group was $80.3{\pm}7.1$ and $69{\pm}17$ respectively. Test group showed 95.23% of success rate and 100% of control group was successful. At 3 and 6months of loading, significantly more bone resorption was observed in test group than in control group (p<0.05). However, there was no significant difference in the bone level change at 12months of loading between two groups (p>0.05). Marginal bone level change showed no significant difference with gender and location (p>0.05). Within the limitation of this study, when primary stability was obtained, immediate loading of GS III implant at posterior region could be predictable treatment option.

• The Journal of Korean Academy of Prosthodontics
• /
• v.51 no.3
• /
• pp.183-189
• /
• 2013

Purpose: The aim of this study was to evaluate clinical outcomes of implant supported fixed-hybrid prostheses (FHP) in the fully edentulous arches. Materials and methods: Patients in this retrospective study were restored with fixed-hybrid prostheses supported by 4 to 6 implants and functioned more than 1 year of loading. Outcome measures were marginal bone change of implant related with sex, anatomical location (maxilla vs. mandible), opposing teeth, loading time of patients, tilting of posterior implant by Mann- Whitney U test and cantilever length of superstructure by regression analysis, and complication rates. Significance level was set P<.05. Results: A total number of 84 implants (16 restorations) placed in 16 patients were observed for 28 months and mean marginal bone loss was $0.53{\pm}0.39mm$. There were no differences of marginal bone loss according to sex, anatomical location (maxilla vs. mandible), opposing teeth, loading time of patients (P>.05), and cantilever length was not significantly related with a marginal bone loss of implant next to cantilever (P>.05). Complication was shown in 11 patients and veneer fracture and dislodging of artificial teeth were most prevalent. Conclusion: Within the limitations of this study, although marginal bone loss of FHP was very little, complication rates were high. Irrespective of tilting of most posterior implants, marginal bone loss of most posterior implants next to cantilever was less than those of the other implants positioned anteriorly. Cantilever length (<17 mm) did not affect a marginal bone loss of most posterior implants.

• Journal of the Korean Society of Radiology
• /
• v.83 no.3
• /
• pp.582-596
• /
• 2022

To accurately interpret knee MRI, it is important not only to know the basic meniscal anatomy but also to distinguish it from that under pathological conditions. Thus, it would be helpful to know the normal meniscus variants (false positives) that could be mistaken for meniscal tears, and tears that could easily be missed and incorrectly diagnosed as normal (false negatives). False positives include synovial recesses, meniscal flounce, the relationship between the popliteus tendon and lateral meniscus, transverse ligament, the anterior root of the meniscus, and meniscofemoral ligament. False negatives include focal radial tears, flap tears, posterior root tears, meniscocapsular separation, and discoid meniscal tears. In this pictorial essay, we reviewed the imaging data obtained in the aforementioned cases.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.20 no.3
• /
• pp.256-262
• /
• 1998

The aim of this study was to evaluate treatment plan and treatment procedure such as bone graft material, timing of bone graft and orthodontic treatment in 31 alveolar cleft bone graft patients treated at the Department of Oral and Maxillofacial Surgery of Chonnam University Hospital from Jan. 1992 to Dec. 1996. Results obtained were as follows : In total 31 patients of alveolar bone grafts, males(64.5%) were more than females(35.5%). The patients' age ranged between 2 - 33 years of age. Secondary bone grafting was the highest incidence(58.1%) when procedures were undertaken in patients between 6 - 16 years of age. In distribution of cleft side, unilateral clefts(93.5%) were the major part with the left side was larger than the right side. The Missing teeth were found most in lateral incisor, the supernumary teeth were found most between lateral incisor and canine. The most common occlusion before operation was class III malocclusion and anterior cross-bite(65.1%), orthodontic treatment was performed similarly between before and after the bone graft. The most common combined operation with alveolar bone graft was secondary cheiloplasty. The complications were 6 cases of bone defect, a case of oronasal fistula, 3 cases of dehiscence. PMCB and DFDB were used bone graft materials. In marginal bone height after operation, PMCB grafts were higher than DFDB grafts and marginal bone level was increased in the PMCB group but not in the DFDB group.

• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.3
• /
• pp.224-231
• /
• 2010

Purpose: This study was to investigate how the crestal module design could affect the level of marginal bone stress around dental implant. Materials and methods: A submerged implant of 4.1 mm in diameter and 10 mm in length was selected as baseline model (Dentis Co., Daegu,Korea).A total of 5 experimental implants of different crestal modules were designed (Type I model : with microthread at the cervical 3 mm, Type II model : the same thread pattern as Type I but with a trans-gingival module, Type III model: the same thread pattern as the control model but with a trans-gingival module, Type IV model: one piece system with concave transgingival part, Type V model: equipped with beveled platform). Stress analysis was conducted with the use of axisy mmetric finite element modeling scheme. A force of 100 N was applied at 30 degrees from the implant axis. Results: Stress analysis has shown no stress concentration around the marginal bone for the control model. As compared to the control model, the stress levels of 0.2 mm areas away from the recorded implant were slightly lower in Type I and Type IV models, but higher in Type II, Type III and Type V models. As compared to 15.09 MPa around for the control model, the stress levels were 14.78 MPa, 18.39 MPa, 21.11 MPa, 14.63 MPa, 17.88 MPa in the cases of Type I, II, III, IV and V models. Conclusion: From these results, the conclusion was drawn that the microthread and the concavity with either crestal or trans-gingival modules maybe used in standard size dental implants to reduce marginal bone stress.

• The Journal of Korean Academy of Prosthodontics
• /
• v.47 no.3
• /
• pp.301-311
• /
• 2009

Statement of problem: Flapless implant surgery using a soft tissue punch device requires a circumferential excision of the mucosa at the implant site. To date, Although there have been several reports on clinical outcomes of flapless implant surgeries, there are no published reports that address the appropriate size of the soft tissue punch for peri-implant tissue healing. Purpose: In an attempt to help produce guidelines for the use of soft tissue punches, this animal study was undertaken to examine the effect of soft tissue punch size on the healing of peri-implant tissue in a canine mandible model. Material and methods: Bilateral, edentulated, flat alveolar ridges were created in the mandibles of six mongrel dogs. After a three month healing period, three fixtures (diameter, 4.0 mm) were placed on each side of the mandible using 3 mm, 4 mm, or 5 mm soft tissue punches. During subsequent healing periods, the peri-implant mucosa was evaluated using clinical, radiological, and histometric parameters, which included Gingival Index, bleeding on probing, probing pocket depth, marginal bone loss, and vertical dimension measurements of the peri-implant tissues. Results: The results showed significant differences (P <0.05) between the 3 mm, 4 mm and 5 mm tissue punch groups for the length of the junctional epithelium, probing depth, and marginal bone loss during healing periods after implant placement. When the mucosa was punched with a 3 mm tissue punch, the length of the junctional epithelium was shorter, the probing depth was shallower, and less crestal bone loss occurred than when using a tissue punch with a diameter $\geq$ 4 mm. Conclusion: Within the limit of this study, the size of the soft tissue punch plays an important role in achieving optimal healing. Our findings support the use of tissue punch that 1 mm smaller than implant itself to obtain better peri-implant tissue healing around flapless implants.

• The Journal of Korean Academy of Prosthodontics
• /
• v.49 no.4
• /
• pp.346-353
• /
• 2011

Purpose: The peri-implant soft tissue is remodeled by the initial marginal bone resorption affecting the prognosis and esthetic result of treatment. Thus various designs on implant neck design are studied to preserve peri-implant bone. The purpose of this study is to review on the causes of initial marginal bone resorption, the configuration of peri-implant soft tissue, and the implant crestal module favorable in preserving peri-implant tissue. Materials and methods: The studies on the causes of initial marginal bone resorption and the implant crestal modules are researched and reviewed using Pubmed database. The implant crestal modules including one piece and two-piece implant, internal and external hex abutment, taper and butt joint connection, scalloped design abutment, and platform switching concept are reviewed. Results: A number of clinical and experimental studies preferred one piece implant to two-piece in preserving initial peri-implant tissue. For two piece implants, internal hex abutment and taper joint connection appear more favorable than external hex abutment and butt joint connection relatively. Controversial issues still exist on scalloped design requiring more studies on it. Although the rationale is not certain, the concept of platform switching seems favorable in preserving initial peri-implant tissue based on clinical and experimental studies. Conclusion: Each implant crestal module contains its own advantages and disadvantages with various controversial issues. In the aspect of preservation of initial peri-implant tissue, however, one-piece implant seems beneficial. In cases when two-piece implant is more appropriate due to prosthodontic concerns or any other problems, the application of platform switching concept, internal connection abutment, and taper joint connection may be favorable for the preservation of peri-implant tissues.