• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.423-430
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• 2016

The implant prosthesis can be divided into the screw retained prosthesis and cement retained prosthesis. Each type has advantages as well as disadvantages which is unfavorable to maintain the implants. To overcome these drawbacks, T-screw system was developed. T-screw system which utilizes a lingual direction of the screw to retain the implant prosthesis, has advantages of retrievability of the prosthesis, passive fit, and possibility to form esthetic and functional occlusal surface. The prior prosthesis which utilized horizontal screws had difficulty in fabrication especially in the case of multiple units, and also limited use with all-ceramic prosthesis. In this case, fabricating the implant prosthesis by using the T-screw system showed superior results in easy maintenance, esthetics, and also functions. In addition, we are to report the method of using the T-screw system in implant prosthesis, such as multiple units of implant prosthesis and all ceramic prosthesis.

• 대한치과보철학회:학술대회논문집
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• 1999.04a
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• pp.61-61
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• 1999

• The Journal of the Korean dental association
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• v.53 no.9
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• pp.628-643
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• 2015

Purpose: The aim of this retrospective study was to compare marginal bone loss and survival rates of double short implants(multiple implant) which had been installed and restored in severely atrophic maxillary molar site without a grafting procedure. Material and Method: The subjects were patients (90 patients, 180 implants) who had been installed double short implants in severely atrophic maxillary single molar site without bone augmentation procedure from 2006 to 2014 in dental clinic in Chuncheon city. Following data were collected from dental records and radiographic panoramic views: patient's age, gender, smoking status, implant site, timing of implant installation, residual ridge height. The correlation between those factors and survival rate and marginal bone loss were analyzed. Statistical analysis was performed using Chi-square test, Student's t- test and ANOVA. Result: Eleven implants in 6 patients failed and the cumulative survival rate was 93.9%. No significant differences were found in relation to the following factors: patient's age, gender, implant site, timing of implant installation (P> .05). There were significant differences in smoking status and residual ridge height(P< .05). The average follow-up time was $45{\pm}14.7months$. The mean marginal bone loss of survived 169 implants was $0.08{\pm}0.59mm$. Conclusion: Despite the short term outcomes, the survival rate of double short implants was comparable to normal length implants. This study demonstrated that placement of double short implants without the use of bone grafting procedure for severely atrophic posterior maxilla is a simple and predictable treatment procedure.

• Journal of Periodontal and Implant Science
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• v.49 no.3
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• pp.185-192
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• 2019

Purpose: Implant wall thickness and the height of the implant-abutment interface are known as factors that affect the distribution of stress on the marginal bone around the implant. The goal of this study was to evaluate the long-term effects of supracrestal implant placement and implant wall thickness on maintenance of the marginal bone level. Methods: In this retrospective study, 101 patients with a single implant were divided into the following 4 groups according to the thickness of the implant wall and the initial implant placement level immediately after surgery: 0.75 mm wall thickness, epicrestal position; 0.95 mm wall thickness, epicrestal position; 0.75 mm wall thickness, supracrestal position; 0.95 mm wall thickness, supracrestal position. The marginal bone level change was assessed 1 day after implant placement, immediately after functional loading, and 1 to 5 years after prosthesis delivery. To compare the marginal bone level change, repeated-measures analysis of variance was used to evaluate the statistical significance of differences within groups and between groups over time. Pearson correlation coefficients were also calculated to analyze the correlation between implant placement level and bone loss. Results: Statistically significant differences in bone loss among the 4 groups (P<0.01) and within each group over time (P<0.01) were observed. There was no significant difference between the groups with a wall thickness of 0.75 mm and 0.95 mm. In a multiple comparison, the groups with a supracrestal placement level showed greater bone loss than the epicrestal placement groups. In addition, a significant correlation between implant placement level and marginal bone loss was observed. Conclusions: The degree of bone resorption was significantly higher for implants with a supracrestal placement compared to those with an epicrestal placement.

• The Journal of the Korean dental association
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• v.49 no.7
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• pp.389-397
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• 2011

Bisphosphonate inhibits the function of osteoclast, so they are widely used for multiple myeloma, Paget's disease, metastatic malignant bone disease, and severe osteoporosis. This drug is very effective for preventing severe complication of osteoporosis, some unpredictable complication occurred such as esophageal malignancy, atypical fracture of femur, and osteonecrosis of the jaw. Bisphosphonate related osteonecrosis of the jaw (BRONJ) is closely related with invasive, open bone surgery like tooth extraction. BRONJ associated with dental implant is rare, however, as the use of bisphosphonate increase, BRONJ cases with dental implant are increasing. In this article, we will describe the considerations during dental implant treatment for patient under bisphosphonate therapy.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.4
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• pp.280-292
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• 2016

Purpose: The purpose of this study was to compare the long-term survival rate and peri-implant marginal bone loss related to multiple risk factors including the clinician's experience. Materials and Methods: Four hundred twenty implants in 146 patients, who had involved a supportive periodontal therapy program every 3 to 6 months and had follow up data for at least 5 years, were selected as the study group. Peri-implant marginal bone loss, data of demographic, implant and surgical characteristics were collected from peri-apical radiographs and chart review. Implant survival was regarded as the remaining with radiographic marginal bone level in excess of 50% of the fixture length for any reason. Results: The cumulative survival rate after 5 years of loading was 94.9%. In binary logistic regression analysis, smoking status (P = 0.033) and presence of spontaneous cover screw exposure (P < 0.001) were significantly related to 5-year survival of implants. In stepwise multiple regression analysis, smoking status (P < 0.001), type of abutment connection (P < 0.001) and implant surface (P = 0.033) were significantly related to peri-implant marginal bone level. And the year of resident was not statistically related to 5-year implant survival in simple logistic regression analysis (P = 0.171). Conclusion: Smoking status, spontaneous cover screw exposure, type of abutment connection and implant surface might influence the implant success. There was no significant correlation between the year of resident and implant failure.

• Applied Microscopy
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• v.42 no.3
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• pp.151-157
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• 2012

The microstructure of various shapes of stacking fault pyramids (SFPs) formed in multiple implant/anneal Separation by Implanted Oxygen (SIMOX) material were investigated by plan-view and cross-sectional transmission electron microscopy. In the multiple implant/anneal SIMOX, the defects in the top silicon layer are confined at the interface of the buried oxide layer at a density of ${\sim}10^6\;cm^{-2}$. The dominant defects are perfect and imperfect SFPs. The perfect SFPs were formed by the expansion and interaction of four dissociated dislocations on the {111} pyramidal planes. The imperfect SFPs show various shapes of SFPs, including I-, L-, and Y-shapes. The shape of imperfect SFPs may depend on the number of dissociated dislocations bounded to the top of the pyramid and the interaction of Shockley partial dislocations at each edge of {111} pyramidal planes.

• Journal of Korean society of Dental Hygiene
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• v.14 no.3
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• pp.371-379
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• 2014

Objectives : The purpose of this study is to investigate the correlation between quality of sleep and dental fear in implant surgery patients. Methods : A self-reported questionnaire was filled out by 153 implant patients from December 2012 to February 2013 in dental clinics and hospitals in Busan and Changwon. Data were analyzed by descriptive analysis, t-test, ANOVA and multiple regression analysis using SAS version 9.20. Results : The quality of sleep in the implant patients was $41.0{\pm}6.0$. The systemic diseases influenced on the quality of sleep and dental fear also affected the quality of sleep. Conclusions : The results of the analysis of a relationship between the fear perception of dental implant surgery patients and the quality of their sleep showed that the patients with systemic diseases, the patients with a fear by the physical stimulation relating to implant treatment showed the low quality of sleep.

• The Journal of Advanced Prosthodontics
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• v.11 no.5
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• pp.271-279
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• 2019

PURPOSE. The newest technologies for digital implant impression (DII) taking are developing rapidly and showing acceptable clinical results. However, scientific literature is lacking data from clinical studies about the accuracy of DII. The aim of this study was to compare digital and conventional dental implant impressions (CII) in a clinical environment. MATERIALS AND METHODS. Twenty-four fixed zirconia restorations supported by 2 implants were fabricated using conventional open-tray impression technique with splinted transfers (CII group) and scan with Trios 3 IOS (3Shape) (DII group). After multiple verification procedures, master models were scanned using laboratory scanner D800 (3Shape). 3D models from conventional and digital workflow were imported to reverse engineering software and superimposed with high resolution 3D CAD models of scan bodies. Distance between center points, angulation, rotation, vertical shift, and surface mismatch of the scan bodies were measured and compared between conventional and digital impressions. RESULTS. Statistically significant differences were found for: a) inter-implant distance, b) rotation, c) vertical shift, and d) surface mismatch differences, comparing DII and CII groups for mesial and distal implant scan bodies ($P{\leq}.05$). CONCLUSION. Recorded linear differences between digital and conventional impressions were of limited clinical significance with two implant-supported restorations.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.14-20
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• 2016

Purpose: The aim of this study was to know whether there is significant difference of peri-implant bone density according to the state of antagonist region. Materials and methods: 51 patients who had implant operation in Daejeon Dental Hospital of Wonkwang University participated in this study and total of 51 implants were analyzed. Implants were classified depending on opposing antagonist region, gender, age and location of jaw. The opposing antagonist region was divided into four groups; natural tooth, implant, pontic and edentulous region. Fractal analysis was performed using two periapical radiographs; one after implant placement and the other after 10 weeks following prosthetic restoration. The analysis was done by Image J. The data was statistically analyzed using one-way ANOVA and Tukey multiple comparison test. Results: The mean value of fractal difference was $0.009{\pm}0.048$ with opposing natural tooth, $0.026{\pm}0.080$ with opposing implant, $0.025{\pm}0.068$ with opposing pontic and $0.093{\pm}0.171$ with opposing edentulous area. There was a statistically significant difference in fractal value between opposing implant and opposing edentulous state. And there was no statistically significant difference according to age, gender and location of jaw. Conclusion: There was no statistically significant difference between 3 groups except opposing edentulous region and there was a statistically significant difference between opposing implant and edentulous region. And there was no statistically significant difference according to age, gender and location of jaw.