• The Journal of Korean Academy of Prosthodontics
• /
• v.29 no.2
• /
• pp.1-16
• /
• 1991

In order to see the possible effect of the functional load-bearing after osseointegration of the titanium root form implant in dog a histologic study was conducted. One side of lower jaw was surgically prepared edentulousness and titanium implants were inserted. Some implants were functionally loaded through fixed detachable prosthesis and some are isolated and unloaded. The dog was sacrificed four months later and bone sections with implants were processed for histologic evaluation and the results were as follows ; (1) The bone to implant interface after four months of load bearing presented no mobility and no marginal bone loss radiographically and histologically. (2) The interface zone between compact bone and implant revealed a direct bone to implant contact and in some areas marrow tissue contacts were examined at the light microscopic level. (3) At the ultrastructural level the interface of surrounding compact bone matrix and implant, three types of superficial layers were found ; one with moderate electron dense amorphous granular substance layer, other with high electron dense fine granular substance layer, and another type of amorphous granular substance covered with high electron dense line of minute granules. (4) The osteoblasts in the marrow tissue neighboring implants and osteocytes in compact bone showed typical normal characteristics and in the marrow tissues some of lymphocytes and mast cells were observed. (5) The abscence of abnormal tissue reactions at a cellular level indicates a high degree of biocompatibility for the experimental titanium implant and basically no difference was found between functionally loaded and unloaded implants.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.41 no.6
• /
• pp.317-321
• /
• 2015

Objectives: The purpose of this study is to evaluate five-year radiographic follow-up results of the Korean sandblasting with large grit, and acid etching (SLA)-treated implant system. Materials and Methods: The subjects of the study are 54 patients who have been followed-up to date, of the patients who underwent implant surgery from May 1, 2009 to April 30, 2011. In all, 176 implant placements were performed. Radiographs were taken before the first surgery, immediately after the first and second surgeries, immediately and six months after the final prosthesis installation, and every year after that. Bone loss was evaluated by the method suggested by Romanos and Nentwig. Results: A total of 176 implant placements were performed - 122 in men and 54 in women. These patients have been followed-up for an average of 4.9 years. In terms of prosthetic appliances, there were 156 bridges and 20 single prostheses. Nine implants installed in the maxillary molar area, three in the mandibular molar area and two in the maxillary premolar area were included in group M, with bone loss less than 2 mm at the crestal aspect of the implant. Of these, eight implants were single prostheses. In all, six implants failed - four in the mandible and two in the maxilla. All of these failures occurred in single-implant cases. The implant survival rate was 98.1% on the maxilla and 94.3% on the mandible, with an overall survival of 96.6%. Conclusion: Within the limitations of this study, implants with the SLA surface have a very superior survival rate in relatively poor bone environments such as the maxilla.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.49 no.5
• /
• pp.278-286
• /
• 2023

Objectives: This review assessed the performance of implant-supported fixed hybrid prostheses in 21 patients who received a total of 137 implants between 2003 and 2010. The implants were evaluated for marginal bone resorption, complications, success rate, and survival rate based on their vertical angularity, type of bone graft, and measured implant stability. Materials and Methods: One-way ANOVA and chi-square tests were used to analyze the relationships among long-term evaluation factors and these variables. The mean initial bone resorption in the implant group with a vertical angle of more than 20° was 0.33 mm and mean final bone resorption was 0.76 mm. In contrast, the mean initial bone resorption in the implant group with a vertical angle of less than 10° was 1.19 mm and mean final bone resorption was 2.17 mm. Results: The results showed that mean bone resorption decreased with an increase in the vertical placement angle of the implants used in fixed hybrid prostheses, as well as in the group without additional bone grafts and those with high implant stability. The success rate of implants placed after bone grafting was found to be higher than those placed simultaneously. Conclusion: These results suggest that implant-supported fixed hybrid prostheses may be an effective treatment option for edentulous patients, and intentionally placing implants with high angularity may improve outcomes.

• The Journal of Korean Academy of Prosthodontics
• /
• v.31 no.1
• /
• pp.129-150
• /
• 1993

Since the restoration or masticatory function is the most important aim of implants, it should be substituted for the role of natural teeth and deliver the stress to the bone under the continous load during function. In natural teeth, stress distribution can be obtained through enamel, dentin and cementum and the elasticity of the periodontal ligament play a role of buffering action. In contrast, implant prosthesis has a very unique characteristics that it delvers the load directly to bone through the implant and superstructure. This fact arise the needs to evaluate the stress distribution of the implant in the mechnical aspects, which has a similar role of natural teeth but different pathway of stress. With 3 kinds of implant in prevalent use, 2 types of experimental PEA implant models were made, axisymmetric and 2-dimensional type. In axisymmetric model, the stiffness of the part including the prosthesis and implant which extrude out of bony surface could be calculated with displacement of the superstructure un er 100N vertical load and then damping effects could be determined through this stiffness. In axisymmetric FEA model, load to the bone could be deduced by evaluation the stress distribution of the designed surface under the 100N vertical force and in 2-dimensional model, 100N eccentric vertical load and 20N horizontal loda. The result are as follows. 1. In every implant, stress to the bone tends to be concenturated on the cortical bone. 2. Though the stress of the cancellous bone is larger at the apex of implants, it is less compared with cortical bone. 3. Under 20N horizontal load, stress of the left and right sides of implant shows a symmetrical pattern. But under 100N eccentric vertical load, loaded side shows much larger stress value. 4. In the 1mm interface, stress distribution among implants tend to have a similar pattern. But under 20N horizontal load apposite side of being loaded shows less stress in IMZ. 5. In the case of screw type implant, stress tends to vary along with screw shape. 6. According to the result determined with microstrain, cancellous bone id generally under the condition of overload, while cortical bone is usually within the limitation of physiologic load. 7. In the Branemark implant, maximum stress to the cortical bone is larger than any other implant except for the condition of 20N horizontal force and 0.05mm interface. 8. Damping effects of implants is maximum in IMZ.

• Journal of Yeungnam Medical Science
• /
• v.20 no.1
• /
• pp.45-52
• /
• 2003

Background: Immediate implant placement has become an acceptable treatment for the edentulous area. The advantages of the immediate implant placement include considerable decrease in time from tooth extraction to placement of the finial prosthesis, fewer surgical procedures, and better acceptance of the overall treatment plans. But the success is dependent on the quantity and quality of the extraction socket. The purpose of this study is to evaluate the success of the immediate implant placement. Materials and Methods: Twenty-one sites in 16 patients were selected for the evaluation of the immediate implant placement. All of the cases were followed using clinical and radiographic examinations. Criteria of success were the absence of peri-implant radiolucency, mobility, and persistent pain or sign of infection. Results: Of the 21 implants, 13 implants have been succeeded. Of the 13 implants, 10 implants were replaced for the periodontal disease and 3 implants were replaced for the trauma. Conclusion: The criteria of the success in immediate implant placement are as follows. 1) Implants placed into fresh extraction sockets have a high rate of survival. 2) Implant should be placed as close as possible to the alveolar crest. 3) Implant placed into available bone beyond the apex have a high success rate.

• The Journal of the Korean dental association
• /
• v.56 no.9
• /
• pp.492-502
• /
• 2018

Anterior maxillary teeth play an important role in determining a person's first impression and facial profile. Implant surgery in esthetic area requires more careful diagnosis, treatment planning, surgery, and prosthetic restoration than in posterior area. To avoid complications in surgery and prosthetic restoration for implants in esthetic area, accurate diagnosis and appropriate case selection become very important. If you have decided to restore the area with implant prosthesis, you have to know exactly where to place an implant. I will discuss the ideal implant position in terms of mesio-distally, apico-coronally, labio-palatally, and implant angulation. And I would like to point out the selection of fixture diameter & length for anterior implant. Finally, a clinical implant prosthesis case in maxillary central incisor will be shown. In conclusion, for superior esthetic outcome in anterior implant prostheses, we must understand the patient's anatomic condition and know our ability.

• Journal of Technologic Dentistry
• /
• v.30 no.1
• /
• pp.49-55
• /
• 2008

In this study, to provide the fundamental data on stable connection method for successful implants prosthesis, We fabricated the solder joint of gold alloy bar specimens by gas flame soldering method and laser welding and soldering method. It compared and studied the tensile strength of two soldering method by universal testing machine. The results using universal testing machine were as follow : The mean of tensile strength of solder joint bar in gas flame soldering method specimens was 363.89 $\pm$17.62 MPa, and the mean strength of laser welding and soldering method was 125.91 $\pm$ 19.66 MPa, so gas flame soldering method was better than laser welding and soldering method and the finding better way to improve tensile strength is needed in laser welding method. On weak loading condition and the part which is needed an accuracy, laser welding method is more effective and on long-span prosthesis and frequent chewing loading part, laser welding technique is recommended first and applying additional gas flame soldering technique would be better for making much more successful prosthesis.

• Journal of Chest Surgery
• /
• v.30 no.8
• /
• pp.739-746
• /
• 1997

A variety of experiments concerning the development of ideal prosthetic grafts for correcting circumferential tracheal defects have been performed. The requirements for an ideal tracheal prosthesis are impermeability to air, consistency to prevent collapse, and acceptance by the host tissue causing a minimum inflammatory reaction, allowing fibroblastic infiltration and epithelialization. The synthetic material, polyurethane(PU), is known as a biocompatible polymer with an inert component. In this study, the tracheal prosthesis was made from microporous PU(30 micrometer in diameter) coated with gelatin and reinforced with isoplastic rings. This procedure provides the prosthesis with a compression strength. The out side diame er of the prosthesis was 20 mm with a length of 30 mm. The gelatin used in the study was obtained from pig skin and immobilized and cross-linked by irradiation(60 Co gamma ray) to promote host tissue incorporation and render the prosthesis epithelization after implantation. Animal experiments using 10 mongrel dogs were performed to compare three kinds of prosthesis; gelatin coated polyurethane graft, uncoated polyurethane graft, and prosthesisf pericadium complex graft. After 6 weeks of implantation, the epithelialization of implants was seen on the gelatin-coated and prosthesisfpericadium complex grafts. Implanted prosthesis were complicated by airway obstruction due to anastomosis granuloma. Early tracheal stenosis was found in the uncoated graft group. Two kind of anastomosis techniques were tested on the gelatin-coated prosthesis. Everted anastomosis resulted severe granuloma than the inverted anastomosis. In the prosthesislpericadium complex graft, bacteria and inflammation at a anastomotic site was found. Based on these results, gelatin coated porous polyurethane trachea prosthesis is biocompatible and may be useful in clinical application with further investigation.

• 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.

• The Journal of Korean Academy of Prosthodontics
• /
• v.56 no.3
• /
• pp.235-242
• /
• 2018

Periodontal and prosthodontic maintenance of implant overdenture is a very important factor for the long term success of the prosthesis and implants. Failure of maintenance can lead to prosthetic failure due to peri-implant bone loss and fracture and wear of the prosthesis or components. In this case, the existing gold milled bars were reconstructed with cobalt chrome milled bar in a manner that does not interfere with the external shape for the retreatment of fractured implant overdenture by maintenance failure. Two implants of mandible were selected strategically and the CM LOC attachments were connected to the two implants, and implant overdentures were fabricated. As a result, prosthesis with a functional and esthetic design that facilitates good hygiene management of the patient was delivered, which is advantageous for long term maintenance, and regular check-ups were scheduled for proper maintenance.