• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.127-134
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• 2022

Among many contributing factors of implant failure, excessive loading and inflammation contribute mainly to increasing implant failure rate. Especially, poor oral hygiene around implants is one of the most common reasons for implant failure. When implant prosthesis fails to function, the clinician should re-diagnose and plan treatment using the remaining implants. Additional implantation may be needed to make a new type of prosthesis or either implant-assisted RPD and implant overdenture treatment may be performed using the remaining implants. In this article, a patient whose fixed implant prosthesis in the maxilla had failed of poor oral hygiene maintenance was reported to be recovered with removable implant overdenture by using remaining implant abutments and a milled bar with additional retentive elements. Through this treatment, the clinical results were satisfactory in terms of esthetics, masticatory function recovery and oral hygiene management.

• The Journal of Korean Academy of Prosthodontics
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• v.55 no.3
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• pp.272-278
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• 2017

Purpose: The aim of the present prospective clinical study was to assess the cumulative survival rate (CSR) of Neobiotech implants restored with fixed partial prosthesis in relation to its potential risk factors. Materials and methods: Thirty six partially edentulous patients received Neobiotech implants and implant supported fixed partial prosthesis at Korea University Guro Hospital Dental Center from November 2009 until November 2011. The observation period was set from the implant placement and the last clinical visit until December 2015. Implant survival rate was determined using the Kaplan-Meier method. The relationship between implant survival rate and the potential risk factors were analysed using the multi Cox proportional analysis (P<.05). Results: A total of 69 implants were placed in 36 patients after a mean observation period of 45.9 months. Two out of 69 implants failed before loading, yielding a 5-year cumulative survival rate of 97.1%. The maxillary implants have a lesser CSR than the mandibular implants based on log rank test analysis (maxilla=91.3%; mandible=100% P<.05). However, the multi Cox proportional analysis showed that implant location has no significant correlation with implant failure (P>.05). Conclusion: Neobiotech implants showed predictable results with a 5 year cumulative survival rate of 97.1%.

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

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.28-40
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• 2010

Purpose: The aim of this retrospective study was to provide long-term data about the correlation between multifactorial local factors and the survival of implants. Material and methods: During 19 years (1991 to 2009), 2796 implants were placed in 879 patients. From dental charts and radiographs, the following data were collected: patient's age at implant placement, gender, implant system, surface, length, diameter, location of implant placement, bone quality, primary stability, type of prosthesis. The correlations between these data and implant survival were analyzed. Statistical analysis was performed using Kaplan-Meier survival analysis, Chi-square test, odds ratio. Results: 1. Among the 2796 implants, 150 implants failed that resulted in a cumulative survival rate of 94.64%. The cumulative survival rate of smooth surface implants (91.76%) was lower than rough surface implants (96.02%). 2. Anatomic location, implant surface, diameter of smooth surface implant, primary stability, type of prosthesis, patient's age and gender were significantly associated with implant survival (P < .05). 3. No significant difference in implant survival was found in relation to the following factors: implant length, bone quality, diameter of rough surface implants and type of rough surface according to implant manufacturer (P < .05). Conclusions: Local factors such as anatomic location, implant surface, diameter of smooth surface implant, primary stability and type of prosthesis have a significant effect on implant survival.

• The Journal of Korean Academy of Prosthodontics
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• v.56 no.2
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• pp.95-104
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• 2018

Purpose: The purpose of this study is to analyze the factors affecting the longevity of failed prosthesis and the success rate of the prosthesis based on the data evaluated with the newly developed Korean Academy of Prosthodontics (KAP) criteria. Materials and methods: Evaluation was performed in the restored prosthesis for patients who visited the prosthodontics department of the 13 dental university hospitals and general hospitals. The status of the prosthesis was classified into four categories: Good, Fair, Bad, Worst. The success was recorded if only the category was classified in 'good'. The mean duration of failed prostheses and the success rate through Kaplan-Meier method were analyzed. Results: A total of 1,804 cases of prosthesis were evaluated: 810 cases of fixed dental prostheses (FDP), 519 cases of Removable Dental Prostheses (RDP), and 475 cases of implant prosthesis. The mean duration of failed FDP was $11.41{\pm}0.30years$ and the median was 10 years. The mean duration of failed RDP was $8.18{\pm}0.29years$ and the median was 7 years. The mean duration of failed implant prosthesis was $7.99{\pm}0.30years$ and the median was 7 years. The factors related to the failure were as follows: number of units, abutments, abutments treated with root canal, and plaque index in FDPs; treated and opposing dentition in RDPs; the number of implants, duration of use, and plaque index in implant prostheses. Conclusion: The average duration of failed prosthesis was 11.41 years for FDPs, 8.18 years for RDPs, and 7.99 years for implant prosthesis, according to the evaluation with newly developed KAP criteria.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.1
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• pp.1-13
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• 2012

Short implants are used in parts which have anatomical structures like maxillary sinus, inferior alveolar nerve and limited alveolar height due to severe alveolar bone resorption. In these case, there are no need of additional bone augmentation so there are advantages like reduced entire treatment time, reduced patient's discomfort and protection of important anatomical structures. The aim of this study is, in implants whose length is less than 10mm, to analyze the impact of implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting on survival rates and marginal bone resorption. The samples used in this study were 227 implants, less than 10mm, placed in 137 patients in Wonkwang university dental hospital implant center. From dental charts the information about implant length, diameter, location of implant placement, presence of bone graft, presence of prosthesis splinting were obtained. Emago advanced v5.6(Oral diagnostic systems, Amsterdam, The Netherlands)program was used to measure the amount of marginal bone resorption. Out of total 227 implants, resulting in 96.5 % of survival rate. There was a tendency toward higher failure rates for the maxilla and bone graft site. No significant difference in marginal bone resorption was found associated with length of implants(p>0.05) and neither with the diameter of implants. Among the risk factors examined, more failure rates of short implants can be attributed to poor bone quality in the maxilla and presence of bone graft. At implants under 10mm, length, diameter, location of implant placement, bone graft and splinting of prosthesis didn't affect marginal bone loss.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.393-400
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• 2016

Fixed implant prosthesis and removable implant overdenture are the main treatment options for treating edentulous maxilla with implants. If clinicians select one of the treatment options without accurate diagnosis and evaluation, this may lead to unfavorable treatment result and one would not be able to guarantee successful long term prognosis. In this case, 69 year-old female presented with failed fixed implant prosthesis that was treated in private dental clinic. Since the patient did not want additional insertion of implants and considering factors such as oral hygiene maintenance, splinting effect, and esthetics, the patient was treated with removable implant bar type overdenture using pre-existing implants. The clinical results were satisfactory in the aspect of esthetics and masticatory function, oral hygiene maintenance.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.2
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• pp.113-124
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• 2023

Purpose. The purpose of this study is to help increase the success rate by analyzing the types and characteristics of implant prosthesis and the survival rate. Materials and methods. Among implants placed between 2011 and 2020 at Sanbon Dental Hospital, College of Dentistry, Wonkwang University, a case restored by a prosthetic surgeon was investigated for the characteristics and correlation of failure. The causes of failure were classified as failure of osseointegration, peri-implantitis, fixture fracture, abutment fracture, screw fracture, screw loosening, prosthesis fracture, and loss of prosthesis retention. Prosthetic method, cantilever presence, placement location, etc. were analyzed for their correlation with implant failure. Results analysis was derived through Chi-square test and Kaplan-Meier survival analysis using SPSS ver 25.0 (IBM, Chicago, IL, USA). Results. A total of 2587 implants were placed, of which 1141 implants were restored with Single Crown and 1446 implants with Fixed Partial Denture, and the cumulative survival rate was 88.1%. The success rate of SC was 86.2% (984) and the success rate of FPD was 89.6% (1295), showing statistically significant differences, among which factors that had significant differences were abutment fracture, screw fracture, and screw loosening (P < .05). Conclusion. As a result of the 10-year follow-up, more failures occurred due to biomechanical factors than biological factors. Further studies on the success of implants will be needed in the future.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.2
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• pp.161-168
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• 2020

Failure of fixed implant supported prosthesis is caused by biomechanical factors such as excessive occlusal stress and biological factors such as bacterial infections and inflammation. Implants with severe bone resorption that have worsened without being resolved due to implant complications should be removed and then new treatments should be planned, taking into account remaining teeth, remaining implants, and residual alveolar. The patient of this case removed some of fixed implant prosthesis of mandible. The condition of the remaining alveolar bone was reassessed for further implant replacement and a few implants were placed. Then implant assisted removable partial denture (IAPRD) treatment is performed using implant surveyed bridge as abutment. Through this treatment, the clinical results were satisfactory on aspect of masticatory function recovery and oral hygiene management.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.1
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• pp.61-66
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• 2012

Purpose: This study was to compare the cumulative survival rate (CSR) of Br${\aa}$nemark machined surface implants and TiUnite$^{TM}$ imlants and to analyze association between risk factors and the CSR of the implants. Materials and methods: A retrospective study design was used to collect long-term follow-up clinical data from dental records of 156 patients treated with 541 Br${\aa}$nemark machined and TiUnite$^{TM}$ implants at Korea University Guro hospital in South Korea from 1993 through 2008. Machined implant and TiUnite$^{TM}$ implant were compared by CSR. Exposure variables such as gender, systemic disease, location, implant length, diameter, prosthesis type, opposing occlusion type, date of implant placement, type of edentulous space, abutment type, existence of splinting with natural teeth, and existence of cantilever were collected. Life table analysis was undertaken to examine the CSR. Cox regression method was conducted to assess the association between potential risk factors and overall CSR (${\alpha}$=.05). Results: Patient ages ranged from 16 to 75 years old (mean age, 51 years old). Implants were more frequently placed in men than women (94 men versus 63 women). Since 1993, 264 Br${\aa}$nemark machined implants were inserted in 79 patients and since 2001, 277 TiUnite$^{TM}$ implants were inserted in 77 patients. A total survival rate of 86.07% was observed in Br${\aa}$nemark and Nobel Biocare TiUnite$^{TM}$ during 15 years. A survival rate of machined implant during 15 years was 82.89% and that of TiUnite$^{TM}$ implant during 5 years was 98.74%. The implant CSR revealed lower rates association with several risk factors such as, systemic disease, other accompanied surgery, implant location, and Kennedy classification. Conclusion: Clinical performance of Br${\aa}$nemark machined and TiUnite$^{TM}$ implant demonstrated a high level of predictability. In this study, TiUnite$^{TM}$ implant was more successful than machined implant. The implant CSR was associated with several risk factors.