• The Journal of Advanced Prosthodontics
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• v.6 no.1
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• pp.35-38
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• 2014

PURPOSE. This study aimed to evaluate the correlation between microleakage and screw loosening at different types of implant-abutment connections and/or geometries measuring the torque values before and after the leakage tests. MATERIALS AND METHODS. Three different abutment types (Intenal hex titanium, internal hex zirconium, morse tapered titanium) with different geometries were connected to its own implant fixture. All the abutments were tightened with a standard torque value then the composition was connected to the modified fluid filtration system. After the measurements of leakage removal torque values were re-measured. Kruskal-wallis test was performed for non-parametric and one-way ANOVA was performed for parametric data. The correlation was evaluated using Spearman Correlation Test (${\alpha}=0.05$). RESULTS. Significantly higher microleakage was found at the connection of implant-internal hex zirconium abutment. Observed mean torque value loss was also significantly higher than other connection geometries. Spearman tests revealed a significant correlation between microleakage and screw loosening. CONCLUSION. Microleakage may provoke screw loosening. Removing torque values rationally decrease with the increase of microleakage.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.473-488
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• 2006

Adequate bone quality and stress distribution to the bone are of decisive importance for implant success. Even though the success rates of dental implants have been high, implant failures do occur. Overloading has been identified as a primary factor behind dental implant failure. The purpose of this study was to theoretically investigate the effect of two types of implants on the stress distribution in poor bone quality. Employing the finite element method, the study modeled a 4.1 mm diameter, 12.0 mm length implant placed in cortical or spongeous bone. A static loading of lOON was applied at the occlusal surface at 0, 30 degrees angle to the vertical axis of the implant. von Mises stresses concentrations in the supporting bone were analyzed with finite element analysis program. The results were as follows; 1. The stresses at the marginal bone were higher under buccal oblique load(30 degrees off of the long axis) than under vertical load. 2. Under buccal oblique load, the stresses were higher at the lingual marginal bone than at the buccal marginal bone, and the differences were almost the same. 3, Under vertical and oblique load, the stress was the highest at the marginal bone and lowest at the bone around apical portions of implant in cortical bone. 4, Under vertical load, Model 1 showed more effective stress distribution than Model 2 irrespective of bone types. On the other hand, Model 2 showed lower stress concentration than Model 1 under buccal oblique load.

• The Journal of the Korean dental association
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• v.47 no.9
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• pp.585-595
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• 2009

Purpose : The aim of this study was to compare surgical complications between simple implant placement and implant placement combined with complicated surgical procedures. We also evaluated prosthetic complications according to the specific types of prosthesis. Material and Method : A retrospective analysis of dental chart of patients who was performed implant therapy during the period from June 2003 to December 2005 was carried out. This study was performed on 408 patients (208 male, 200 female). In addition, 1671 implants were performed. Based on their medical record and radiographs, the authors evaluated surgical and prosthetic complications, surgical procedures accompanied at the time of implant, risk factors of implant failure etc. Result : Surgical complications were developed on 358 implants(21.4% on total placed implants) and wound dehiscence was most prevalent complication. On maxillary posterior area, surgical complications developed more frequently on implants with major surgery and showed a significant difference. And complication rate of implants accompanied with GBR was higher than that of simple implants placement and also showed significant difference. The implant supported prosthesis showed no statistical difference in the occurrence of complications according to the types of prosthesis, and food retention was the most common post-prosthetic complication. Also we speculated that length and width of implant showed significant correlation to the failure of implant primary osseointegration. Conclusion : Based on the result, clinician should provide more careful maintenance for patients with implant placement accompanied by complicated surgical procedure. And periodic maintenance for the patient is requested for long-term survival of implant therapy.

• The Journal of Advanced Prosthodontics
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• v.8 no.4
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• pp.313-320
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• 2016

PURPOSE. The aim of this study was to evaluate the clinical findings and patient satisfaction on implant overdenture designed with Locator implant attachment or Locator bar attachment in mandibular edentulous patients. MATERIALS AND METHODS. Implant survival rate, marginal bone loss, probing depth, peri-implant inflammation, bleeding, plaque, calculus, complications, and satisfaction were evaluated on sixteen patients who were treated with mandibular overdenture and have used it for at least 1 year (Locator implant attachment: n=8, Locator bar attachment: n=8). RESULTS. Marginal bone loss, probing depth, plaque index of the Locator bar attachment group were significantly lower than the Locator implant attachment group (P<.05). There was no significant difference on bleeding, peri-implant inflammation, and patient satisfaction between the two denture types (P>.05). The replacement of the attachment components was the most common complication in both groups. Although there was no correlation between marginal bone loss and plaque index, a significant correlation was found between marginal bone loss and probing depth. CONCLUSION. The Locator bar attachment group indicates lesser marginal bone loss and need for maintenance, as compared with the Locator implant attachment group. This may be due to the splinting effect among implants rather than the types of Locator attachment.

• Journal of Periodontal and Implant Science
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• v.39 no.3
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• pp.293-301
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• 2009

Purpose: The purpose of this study is to show the total survival rate of implants with maxillary sinus floor elevation and the effects that reach the survival rate by classifying types of graft materials, implant surface, operation method, bone height. Methods: In a total of 131 patients, 251 implants with sinus floor elevation were installed simultaneously or after regular healing. Various bone grafts (autograft, xonograft, allograft, alloplast) and implant surface (MTX-HA implant, chemical etching implant, Titanium oxide surface implant, resorbable blasting media implant, resorbable blast texturing implant, HA-coated implant) were used. All implants were investigated clinically and radiographically, being with 1 to 5 years follow-up period after installation. Results: The survival rate of 251 implants with maxillary sinus floor elevation was 94%. The types of implant, surface, graft material, bone height have no statistically signi-ficant differencies. Conclusions: It can be suggested that maxillary sinus floor elevation may have predictable result with various bone graft materials and implant surface.

• Journal of Periodontal and Implant Science
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• v.52 no.6
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• pp.496-508
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• 2022

Purpose: This study aimed to compare the long-term survival rate and peri-implant marginal bone loss between different types of dental implant-abutment connections. Methods: Implants with external or internal abutment connections, which were fitted at Gangneung-Wonju National University Dental Hospital from November 2011 to December 2015 and followed up for >5 years, were retrospectively investigated. Cumulative survival rates were evaluated for >5 years, and peri-implant marginal bone loss was evaluated at 1- and 5-year follow-up examinations after functional loading. Results: The 8-year cumulative survival rates were 93.3% and 90.7% in the external and internal connection types, respectively (P=0.353). The mean values of marginal bone loss were 1.23 mm (external) and 0.72 mm (internal) (P<0.001) after 1 year of loading, and 1.20 mm and 1.00 mm for external and internal abutment connections, respectively (P=0.137) after 5 years. Implant length (longer, P=0.018), smoking status (heavy, P=0.001), and prosthetic type (bridge, P=0.004) were associated with significantly greater marginal bone loss, and the use of screw-cement-retained prosthesis was significantly associated (P=0.027) with less marginal bone loss. Conclusions: There was no significant difference in the cumulative survival rate between implants with external and internal abutment connections. After 1 year of loading, marginal bone loss was greater around the implants with an external abutment connection. However, no significant difference between the external and internal connection groups was found after 5 years. Both types of abutment connections are viable treatment options for the reconstruction of partially edentulous ridges.

• The Journal of Advanced Prosthodontics
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• v.3 no.1
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• pp.10-15
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• 2011

PURPOSE. This study investigated the influence of bone quality and surgical technique on the implant stability quotient (ISQ) value. In addition, the influence of interfacial bone quality, directly surrounding the implant fixture, on the resonance frequency of the structure was also evaluated by the finite element analysis. MATERIALS AND METHODS. Two different types of bone (type 1 and type 2) were extracted and trimmed from pig rib bone. In each type of bone, the same implants were installed in three different ways: (1) Compaction, (2) Self-tapping, and (3) Tapping. The ISQ value was measured and analyzed to evaluate the influence of bone quality and surgical technique on the implant primary stability. For finite element analysis, a three dimensional implant fixture-bone structure was designed and the fundamental resonance frequency of the structure was measured with three different density of interfacial bone surrounding the implant fixture. RESULTS. In each group, the ISQ values were higher in type 1 bone than those in type 2 bone. Among three different insertion methods, the Tapping group showed the lowest ISQ value in both type 1 and type 2 bones. In both bone types, the Compaction groups showed slightly higher mean ISQ values than the Self-tapping groups, but the differences were not statistically significant. Increased interfacial bone density raised the resonance frequency value in the finite element analysis. CONCLUSION. Both bone quality and surgical technique have influence on the implant primary stability, and resonance frequency has a positive relation with the density of implant fixture-surrounding bone.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.6
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• pp.591-601
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• 2008

STATEMENT OF PROBLEM: The improvement in oral function and comfort from the dental implant appears to depend on the particular type of implant support used with the denture. The number and positioning of implants have an influence on the force transfer and subsequent stress distribution around implants. Nevertheless, a quantitative comparison has not been made between the types of implant prosthesis used with different materials compared to conventional complete denture. PURPOSE: The objective of this study is to assess the masticatory performance, bite force and impact of two different type of implant supported prostheses on oral health-related quality of life compared to conventional complete denture with GOHAI, validated oral-specific health status measures, the sieving method, and the Prescale Dental System. MATERIAL AND METHODS: From the years 1999 to 2006, a total of 30 completely edentulous patients in a single arch were selected from the Yonsei University Dental Hospital, Department of Prosthodontics and Implant Clinic in Seoul, S. Korea. Patients were divided into 3 groups of 10 each. Group HR was restored with fixed-detachable hybrid prostheses with resin teeth. Group FP had fixed dentures with porcelain teeth while Group CD had a complete denture. The masticatory performance was compared between 3 groups. RESULTS: The results showed a significant improvement in oral health-related quality of life with dental implants compared to a conventional denture in GOHAI comparison. Overall, implant prostheses showed a higher masticatory performance ($S_{50}$) and maximum bite force compared with conventional dentures (P < .05) but no differences between different implant supported prostheses (P > .05). CONCLUSION: Within the limitation of this study, the numbers of implant and material of implant prostheses does not appear to impact patient satisfaction, masticatory performance or bite force.

• The Journal of Advanced Prosthodontics
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• v.12 no.1
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• pp.38-48
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• 2020

PURPOSE. The objective of this literature review was to analyze the cumulative survival rates (CSRs) of rigid and non-rigid double-crown-retained removable dental prostheses. MATERIALS AND METHODS. Screening of the literature published from January 1995 to December 2019 was performed by using electronic data base (Pubmed) and manual search. The CSRs of rigid and non-rigid double crown removable dental prostheses were investigated. RESULTS. A total of 403 articles were reviewed and 56 relevant articles of them were selected. Subsequently, 25 articles were included for data extraction. These articles were classified according to rigid and non-rigid type double crowns and further subdivided into teeth, implants, and teeth-implant combination types. The CSRs of rigid type double crown ranged from 68.9% to 95.1% of 5 to 10 years in tooth abutments, 94.02% to 100% over a 3-year mean observation periods in implant abutments, and 81.8% to 97.6% in tooth-implant combination. Non-rigid type double crowns had various CSR ranges from 34% to 94% maximum during 10 years observation in teeth abutment. The CSRs of non-rigid type had over 98% in implant abutments, and ranged from 85% to 100% in tooth-implant combination. CONCLUSION. The CSRs of double crowns varies according to types. With accurate evaluation of the remaining teeth and plan of the strategic implant placement, it could be successful treatment alternatives for partially or completely edentulous patients.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.5
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• pp.687-697
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• 1999

A finite element analysis has been utilized to analyze stress and strain fields and design a new configuration in orthopedics and implant dentistry. Load transfer and stress analysis at implant bone interface are important factors from treatment planning to long term success. Bone configuration and quality are different according te anatomy of expecting implantation site. The purpose of this study was to compare the stress distribution in maxilla and mandible accord-ing to implant length and bone engagement types. A three dimensional axi-symmetric implant model(Nobel Biocare, Gothenburg, Sweden) with surrounding cortical and cancellous bone were designed to analyze the effects of bone engagement and implant length on stress distribution. ANSYS 5.5 finite element program was utilized as an interpreting toot. Three cases of unicortical anchorage model with 7, 10, 13 mm length and four cases of bicortical anchorage model with 5, 7, 10 and 13 mm length were compared both maxillary and mandibular single implant situation. Within the limits of study, following conclusions were drawn. 1. There is a difference in stress distribution according to cortical and cancellous bone thickness and shape. 2. Maximum stress was shown at the top of cortical bone area regardless of bone engagement types. 3. Bicortical engagement showed less stress accumulation when compared to unicortical case overall. 4. Longer the implant future length, less the stress on cortical bone area, however there is no difference in mandibular bicortical engagement case.