• 대한치과보철학회지
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• 제41권2호
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• pp.169-181
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• 2003

Statement of problem : The survival rate of wide diameter implants was lower than of 3.75-mm implants in some clinical researches. Purpose : The purpose of this study was to investigate the influence of implant diameter on the osseointegration of implants in the rabbit femoral condyle and tibial metaphyses by means of removal torque measurements and histomorphometric analysis. Material and Method : Ten adult New Zealand White rabbits were used in this study Two 3.75-mm diameter implants were inserted through one cortical layer in the tibial metaphyses and one 3.75-mm diameter implant was inserted in the femoral condyle. 5.0-mm diameter implants were inserted in the other leg in the same manner. A total of 60 implants (3.75-mm diameter implants:30 : 5.0-mm diameter implants:30) were installed. After a healing time of 4 and 12 weeks, the peak removal torque values required to shear off the implants were recorded. From the removal torque values (Ncm) obtained, the mean shear stress ($N/mm^2$) was calculated. And the percentage of direct bone-to-implant contact and the percentage of bone area inside the thread were measured by Kappa Image Base-metreo. The Student's t-test was undertaken for statistical analysis (p<0.05). Results : The removal torque value of 5.0-mm diameter implants was higher than of 3.75-mm diameter implants (p<0.05). The difference of shear stress value between 3.75-mm and 5.0-mm diameter implants was not statistically significant (p>0.05). The percentage direct bone-to-implant contact had no statistical difference between two groups (p>0.05). The percentage of bone area inside the thread had no statistical difference between two groups (p>0.05). Conclusion It is concluded that the quality f osseointegration is not influenced by increasing implant diameter.

• 대한치과보철학회지
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• 제31권3호
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• pp.411-422
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• 1993

Osseointegrated dental implants are now an accepted part of the prosthetic treatment of fully and partially edentulous patients. Clinical studies have shown that osseointegrated dental implants may successfully be used as abutments for prosthetic rehabilitations, and that the supporting tissue can be kept in a stable and healthy clinical state for prolonged periods of time. The purpose of this study was to look for differences in the distribution in the bacterial morphotypes around natural teeth and osseointegrated dental implants. The subgingival plaque around natural teeth and implants was analysed by means of differential phase-contrast microscopy. In addition, clinical indices used to analyse natural teeth condition were used to compare the condition of natural teeth and implants. The results were as follows : 1. In implants of partially edentulous patients, the plaque index, sulcus bleeding index(P<0.05), pocket depth(P<0.01) were greater than natural teeth. 2. Gingival crevicular fluid volume was not significantly different between natural teeth and implants. 3. In implants of fully edentulous patients, the plaque index was greater than natural teeth(P<0.01) and implants of partially edentulous patients(P<0.05), but sulcus bleeding index was not significantly different. 4. In partially edentulous patient, coccoid cell proportion was greater in implants than natural teeth (P<0.05). 5. In implants of fully edentulous patients, coccid cell proportion was even greater than implants of partially edentulous patients(P<0.05) and natural teeth(P<0.01). 6. Among three groups, the proportions of non-motile rods, motile rods, spirochetes and others were not significantly different. 7. The proportion of motile bacteria was not significantly different among three group.

• Journal of Periodontal and Implant Science
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• 제52권3호
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• pp.230-241
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• 2022

Purpose: The purpose of this study was to evaluate failed implants and reimplantation survival and to identify the relative risk factors for implant re-failure. Methods: Ninety-one dental implants were extracted between 2006 and 2020 at the National Health Insurance Service Ilsan Hospital, including 56 implants in the maxilla and 35 implants in the mandible that were removed from 77 patients. Patient information (e.g., age, sex, and systemic diseases) and surgical information (e.g., the date of surgery and location of the implants and bone grafts) were recorded. If an implant prosthesis was used, prosthesis information was also recorded. Results: In total, 91 first-time failed dental implants in 77 patients were analyzed. Of them, 69 implants in 61 patients received reimplantation after failure. Sixteen patients (22 implants) refused reimplantation or received reimplantation at a different site. Eight of the 69 reimplants failed again. The 1-year survival rate of the 69 reimplants was 89.4%. Age at reimplantation and smoking significantly increased the risk of reimplantation failure. However, a history of taking anti-thrombotic agents showed a statistically significant negative association with reimplantation failure. Of the failed implants, 66% showed early failure and 34% showed late failure of the initial implantation. All 8 re-failed implants showed early failure. Only 3 of these 8 failed reimplants were re-tried and the second reimplants all survived. Conclusions: The total survival rate of implants, which included reimplants and second reimplants was 99.2%, although the survival rate of the initial implantations was 96.3%. Previous failure did not affect the success of the next trial. Reimplantation failure was more strongly affected by patient factors than by implant factors. Therefore, each patient's specific factors need to be meticulously controlled to achieve successful reimplantation.

• Journal of Periodontal and Implant Science
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• 제35권1호
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• pp.65-76
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• 2005

This retrospective study evaluates the clinical performance of the recently introduced $XiVE^{(R)}$ implant(Dentsply-Friadent) with a new macro-design to improve primary stability. A total of 208 $XiVE^{(R)}$ implants (101 in the maxilla and 107 in the mandible) were placed in 71 patients. The average age of the patients was 49 years. Of the 208 implants, 190 (91.3%) were posterior implants and 82 (39.4%) were placed in compromised sites (grafted sites). Clinical and radiographic evaluation were made at second stage surgery for exposure and after functional loading. 192 implants in 64 patients were evaluated at exposure and 146 implants in 50 patients were loaded (average 170 days-loading) and evaluated after functional loading. Of 192 implants available for evaluation before loading, 3 implants failed (early failure) ; 1 before exposure, 1 at exposure and 1 during prosthetic procedure. 2 implants were in the maxilla and 1 was in the mandible. The success rate before loading was 98.4%. After functional loading, no implant failure was occurred in 146 implants evaluated during this period (100% interval success rate). This preliminary data with a new implant showed excellent success 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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• 제29권2호
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• pp.267-284
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• 1991

Since the concept of a direct contact between bone and implants, without interposed soft- tissue layers, was reported by Dr. $Br{\aa}nemark$, there has been increasing necessity for correct under-standing of bone-implant interface and surrounding tissue response. Beside quality of bone, surgical technique, load applied to implants, one must consider implant materials, design and surface characteristics to obtain osseointegration. In this study HA plasma-sprayed implants, TPS implants and $Al_2O_3$ implants were inserted into the alveolar bone of dog and tissue response was observed with radiograph, stereoscope, light microscope, and scanning electron microscope. Results were as follows : 1. There was rapid and active bone formation in the region adjacent to HA plasma-sprayed implants but in the deep supporting bone only slight bone formation was seen. 2. There was considerable lamella bone formation in the region adjacent to TPS implants and the deep supporting bone became more compact. 3. There was some gap and sclerosing bone formation in the adjacent region of $Al_2O_3$ implants, but there was irregular new bone formation in the deep supporting bone. Therefore, it seems that $Al_2O_3$ is not adequate for osseointegrated implants.

• 대한치과의사협회지
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• 제57권7호
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• pp.372-378
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• 2019

The dental implants in modern dentistry brought out a new era in everyday dental practice. Increasing of dental implants usage, various failures and complications has occurred. Failures and complications of dental implant treatments that can happen in implant surgery, in mechanical or prosthetic problem and in biological aspect. The aim of this study was to assess implant failures for 6 years as well as find out how to overcome implant failure. In Jeju National University hospital, 26 dental implants in 17 patients were removed by implant failure through 2013.1.1.-2018.12.31. Each implant failure case was analyzed in report form with various informations about failure retrospectively. The present study showed 26 failed dental implants of 17 patients were removed. 13 implants(50%) of 8 patients(47.06%) were failed before functional loading and 13 implants(50%) of 9 patients(52.94%) were failed after functional loading. 11 implants(42.31%) of 7 patients(41.18%) with medical disease were extracted. 6 implants(23.08%) of 5 patients(29.41%) with additive bone graft were failed. We discuss with 26 failed dental implants of 17 patients about their causes, solutions and prevention retrospectively for 6 past years. Precise diagnosis and treatment planning are needed. Medically compromised patients and patients with implants and additive bone grafts should be cautiously treated with high failing possibilities.

• Archives of Plastic Surgery
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• 제50권2호
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• pp.160-165
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• 2023

Background The number of cosmetic and reconstructive surgeries that use breast implants is increasing in Korea. Recently, it has been reported that breast implant-associated anaplastic large-cell lymphoma is related to textured breast implants, and interest in classification according to the texture of breast implants is increasing. However, there is currently no clear and unified classification. In particular, the definition of "microtextured" is highly varied. In this study, we retrospectively investigated and analyzed the clinical outcomes of smooth and microtextured breast implants. Methods A retrospective chart review of all patients who underwent breast augmentation surgery with smooth and microtextured silicone gel implants between January 2016 and July 2020 was performed. We retrospectively analyzed implant manufacturer, age, body mass index (BMI), smoking status, incision location, implant size, follow-up period, complications, and reoperation rate. Results A total of 266 patients underwent breast augmentation surgery, of which 181 used smooth silicone gel implants and 85 used microtextured silicone gel implants. Age, BMI, smoking status, implant size, and follow-up period were not significantly different between the two groups. Similarly, complications and reoperation rates were not significantly different between the two groups. Conclusion It is important to provide information regarding the clinical risks and benefits of breast implants to surgeons and patients through a clear and unified classification according to the texture of the breast implant.

• 대한치과보철학회지
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• 제36권4호
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• pp.615-643
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• 1998

The purpose of this study was to evaluate the effect of cantilever length, load, and implant number on the stress distribution of implant supported fixed prosthesis. In the replica of an edentulous human mandible, four or five implants were placed and spaced evenly between the mental foramina and symmetrical gold alloy cast superstructures with cantilever were fabricated. Strain gauges were placed in buccal and lingual side of implants. 9, 15, 21kg of loads at varying cantilever lengths were applied to the occlusal surface of fixed prostheses. The strains were recorded from each gauge and principal stresses were calculated The results were as follows : 1. Increasing the length of the cantilever increased the stresses on the bone supporting implants. and the ratio of increase became high as increasing the load. 2. In the model with four implants, the highest compressive stress was measured on lingual side of the first implants nearest loading point and the highest tensile stress was measured on buccal side of the second implants. 3. In the model with five implants, the highest compressive stress was measured on lingual side of the first implants nearest loading point. And the highest tensile stress was measured on buccal side of the second implants, and lingual side of the third implants. 4. There was no significant change of the magnitude of stress on the most distal imp]ant of non cantilevered side as increasing the cantilever length or load. 5. In general, the superstructure supported by five implants reduced the stress and was less affected by cantilever length compared to the support provided by four implants.

• 대한치과교정학회지
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• 제47권4호
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• pp.229-237
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• 2017

Objective: The aim of this study was to compare the initial stability as insertion and removal torque and the clinical applicability of novel orthodontic zirconia micro-implants made using a powder injection molding (PIM) technique with those parameters in conventional titanium micro-implants. Methods: Sixty zirconia and 60 titanium micro-implants of similar design (diameter, 1.6 mm; length, 8.0 mm) were inserted perpendicularly in solid polyurethane foam with varying densities of 20 pounds per cubic foot (pcf), 30 pcf, and 40 pcf. Primary stability was measured as maximum insertion torque (MIT) and maximum removal torque (MRT). To investigate clinical applicability, compressive and tensile forces were recorded at 0.01, 0.02, and 0.03 mm displacement of the implants at angles of $0^{\circ}$, $10^{\circ}$, $20^{\circ}$, $30^{\circ}$, and $40^{\circ}$. The biocompatibility of zirconia micro-implants was assessed via an experimental animal study. Results: There were no statistically significant differences between zirconia micro-implants and titanium alloy implants with regard to MIT, MRT, or the amount of movement in the angulated lateral displacement test. As angulation increased, the mean compressive and tensile forces required to displace both types of micro-implants increased substantially at all distances. The average bone-to-implant contact ratio of prototype zirconia micro-implants was $56.88{\pm}6.72%$. Conclusions: Zirconia micro-implants showed initial stability and clinical applicability for diverse orthodontic treatments comparable to that of titanium micro-implants under compressive and tensile forces.

• Journal of Yeungnam Medical Science
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• 제36권1호
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• pp.43-49
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• 2019

Background: In the osseointegration of dental implants, the implant surface properties have been reported to be some of the most important critical factors. The effect of implant's surfaces created by resorbable blast media (RBM) followed by laser ablation on bone tissue reactions was examined using the removal torque test and histomorphometric analysis. Methods: Two types of dental implants, RBM-laser implants (experimental group) and RBM implants (control group) (CSM implant system, Daegu, Korea; L=6 mm, diameter=3.75 mm) were placed into the right and left distal femoral metaphysis of 17 adult rabbits. Six weeks after placement, removal torque was measured and histomorphometric analysis was performed. Results: The mean removal torque was $24.0{\pm}10.2Ncm$ and $46.6{\pm}16.4Ncm$ for the control and test specimens, respectively. The experimental RBM-laser implants had significantly higher removal torque values than the control RBM implants (p=0.013). The mean values of total and cortical bone to implant contact (BIC) were respectively $46.3{\pm}10.8%$ and $65.3{\pm}12.5%$ for the experimental group, and $41.9{\pm}18.5%$ and $57.6{\pm}10.6%$ for the control group. The experimental RBM-laser implants showed a higher degree of total and cortical BIC compared with RBM implants, but there was no statistical significance (p=0.482, 0.225). Conclusion: The removal torque and BIC of the test group were higher than those of the control group. In this study, the surface treatment created by RBM treatment followed by laser ablation appears to have a potential in improving bone tissue reactions of dental implants.