• The Journal of Advanced Prosthodontics
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• v.8 no.1
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• pp.53-61
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• 2016

PURPOSE. This study conducted an analysis of cost-effectiveness of the implant and conventional fixed dental prosthesis (CFDP) from a single treatment perspective. MATERIALS AND METHODS. The Markov model for cost-effectiveness analysis of the implant and CFDP was carried out over maximum 50 years. The probabilistic sensitivity analysis was performed by the 10,000 Monte-Carlo simulations, and cost-effectiveness acceptability curves (CEAC) were also presented. The results from meta-analysis studies were used to determine the survival rates and complication rates of the implant and CFDP. Data regarding the cost of each treatment method were collected from University Dental Hospital and Statistics Korea for 2013. Using the results of the patient satisfaction survey study, quality-adjusted prosthesis year (QAPY) of the implant and CFDP strategy was evaluated with annual discount rate. RESULTS. When only the direct cost was considered, implants were more cost-effective when the willingness to pay (WTP) was more than 10,000 won at $10^{th}$ year after the treatment, and more cost-effective regardless of the WTP from $20^{th}$ year after the prosthodontic treatment. When the indirect cost was added to the direct cost, implants were more cost-effective only when the WTP was more than 75,000 won at the $10^{th}$ year after the prosthodontic treatment, more than 35,000 won at the $20^{th}$ year after prosthodontic treatment. CONCLUSION. The CFDP was more cost-effective unless the WTP was more than 75,000 won at the $10^{th}$ year after prosthodontic treatment. But the cost-effectivenss tendency changed from CFDP to implant as time passed.

• The Journal of Advanced Prosthodontics
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• v.14 no.3
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• pp.182-202
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• 2022

PURPOSE. The aim of this study is to summarize various biomechanical aspects in evaluating the long-term stability of dental implants based on finite element method (FEM). MATERIALS AND METHODS. A comprehensive search was performed among published studies over the last 20 years in three databases; PubMed, Scopus, and Google Scholar. The studies are arranged in a comparative table based on their publication date. Also, the variety of modeling is shown in the form of graphs and tables. Various aspects of the studies conducted were discussed here. RESULTS. By reviewing the titles and abstracts, 9 main categories were extracted and discussed as follows: implant materials, the focus of the study on bone or implant as well as the interface area, type of loading, element shape, parts of the model, boundary conditions, failure criteria, statistical analysis, and experimental tests performed to validate the results. It was found that most of the studied articles contain a model of the jaw bone (cortical and cancellous bone). The material properties were generally derived from the literature. Approximately 43% of the studies attempted to examine the implant and surrounding bone simultaneously. Almost 42% of the studies performed experimental tests to validate the modeling. CONCLUSION. Based on the results of the studies reviewed, there is no "optimal" design guideline, but more reliable design of implant is possible. This review study can be a starting point for more detailed investigations of dental implant longevity.

• The Journal of Advanced Prosthodontics
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• v.1 no.1
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• pp.31-36
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• 2009

PURPOSE. To determine the change in stability of single-stage, three different design of implant systems in humans utilizing resonance frequency analysis for early healing period(24 weeks), without loading. MATERIAL AND METHODS. Twenty-five patients were included into this study. A total of 45 implants, three different design of implant systems(group A,C,R) were placed in the posterior maxilla or mandible. The specific transducer for each implant system was used. ISQ(implant stability quotient) reading were obtained for each implant at the time of surgery, 3, 6, 8, 10, 12, 24 weeks postoperatively. Data were analyzed for different implant type, bone type, healing time, anatomical locations. RESULTS. For each implant system, a two-factor mixed-model ANOVA demonstrated that a significant effect on ISQ values(group A=0.0022, C=0.017, R=0.0018). For each implant system, in a two-factor mixed model ANOVA, and two-sample t-test, the main effect of jaw position(P > .005) on ISQ values were not significant. CONCLUSIONS. All the implant groups A, C and R, the change patterns of ISQ over time differed by bone type. Implant stability increased greatly between week 0 and week six and showed slow increase between week six and six months(plateau effect).

• Journal of Periodontal and Implant Science
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• v.53 no.6
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• pp.444-452
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• 2023

Purpose: The aim of this study was to retrospectively evaluate the survival and failure rates of RESTORE^® implants over a follow-up period of 10-15 years at a university dental hospital and to investigate the factors affecting the survival rate of these dental implants. Methods: A total of 247 RESTORE^® dental implants with a resorbable blast media (RBM) surface inserted in 86 patients between March 2006 and April 2011 at the Department of Periodontology of Seoul National University Dental Hospital were included. Patients with follow-up periods of less than 10 years were excluded, and data analysis was conducted based on dental records and radiographs. Results: Over a 10- to 15-year period, the cumulative survival rate of the implants was 92.5%. Seventeen implants (6.88%) were explanted due to implant fracture (n=10, 4.05%), peri-implantitis (n=6, 2.43%), and screw fracture (n=1, 0.4%). The results of univariate regression analysis using a Cox proportional hazards model demonstrated that implants placed in male patients (hazard ratio [HR], 4.542; 95% confidence interval [CI], 1.305-15.807; P=0.017) and implants that supported removable prostheses (HR, 15.498; 95% CI, 3.105-77.357; P=0.001) showed statistically significant associations with implant failure. Conclusions: Within the limitations of this retrospective study, the RESTORE^® dental implant with an RBM surface has a favorable survival rate with stable clinical outcomes.

• Journal of Periodontal and Implant Science
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• v.54 no.2
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• pp.96-107
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• 2024

Purpose: Deproteinized bovine bone or synthetic hydroxyapatite are 2 prevalent bone grafting materials used in the clinical treatment of peri-implant bone defects. However, the differences in bone formation among these materials remain unclear. This study evaluated osteogenesis kinetics in peri-implant defects using 2 types of deproteinized bovine bone (Bio-Oss^® and Bio-Oss/Collagen^®) and 2 types of synthetic hydroxyapatite (Apaceram-AX^® and Refit^®). We considered factors including newly generated bone volume; bone, osteoid, and material occupancy; and bone-to-implant contact. Methods: A beagle model with a mandibular defect was created by extracting the bilateral mandibular third and fourth premolars. Simultaneously, an implant was inserted into the defect, and the space between the implant and the surrounding bone walls was filled with Bio-Oss, Bio-Oss/Collagen, Apaceram-AX, Refit, or autologous bone. Micro-computed tomography and histological analyses were conducted at 3 and 6 months postoperatively (Refit and autologous bone were not included at the 6-month time point due to their rapid absorption). Results: All materials demonstrated excellent biocompatibility and osteoconductivity. At 3 months, Bio-Oss and Apaceram-AX exhibited significantly greater volumes of formation than the other materials, with Bio-Oss having a marginally higher amount. However, this outcome was reversed at 6 months, with no significant difference between the 2 materials at either time point. Apaceram-AX displayed notably slower bioresorption and the largest quantity of residual material at both time points. In contrast, Refit had significantly greater bioresorption, with complete resorption and rapid maturation involving cortical bone formation at the crest at 3 months, Refit demonstrated the highest mineralized tissue and osteoid occupancy after 3 months, albeit without statistical significance. Conclusions: Overall, the materials demonstrated varying post-implantation behaviors in vivo. Thus, in a clinical setting, both the properties of these materials and the specific conditions of the defects needing reinforcement should be considered to identify the most suitable material.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.173.2-173.2
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• 2005

• Journal of Technologic Dentistry
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• v.40 no.2
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• pp.63-69
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• 2018

Purpose: The purpose of this study is to investigate the non-precious metal core materials used in the dental laboratory to fabricate the implant superstructure by CAD / CAM method. And to observe and compare the morphology and distribution of the osteoblasts in relation to implant osseointegration. Methods: In this study, the mandibular right first molar tooth model was selected as an international standard to produce a single core. Using this model, the impression was made with the silicone rubber, the tooth model was scanned, and a single core was designed and 5-axis milling was performed. The materials used were Cobalt-Chromium and Nickel-Chromium, and the cores for dental implant top structures were fabricated according to the procedures of the dental labs. After the fabrication, the marginal area of the core was separated and cell culture experiment was performed. The osteoblast cells used MC3T3-E1, which is currently widely used. For morphological analysis of osteoblasts, cells were posttreated and observed using CLSM (Confocal Laser Scanning Microscope) and compared. Results: The cell adhesion behavior of the specimen surface measured by CLSM was uniformly distributed in specimen A (Cobalt-Chromium) than in specimen B (Nickel-Chromium). The distribution and changes of the cells were different in the two specimens. Conclusion : It is possible to confirm that specimen A (Cobalt-Chromium) is suitable for the living body through adhesion and proliferation of osteoblasts related to implant osseointegration in the non-precious metal superstructure used after implantation. It is considered that it is preferable to use Co-Cr when fabricating the superstructure.

• Journal of Periodontal and Implant Science
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• v.54 no.4
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• pp.280-291
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• 2024

Purpose: This study aimed to investigate whether new-onset periodontitis or apical periodontitis in the adjacent teeth affects osseointegrated dental implants in a beagle dog model. Methods: One control group and 2 experimental groups (periodontitis and apical periodontitis groups) were defined based on the presence of experimental periodontitis or apical periodontitis, with 1 beagle dog randomly assigned to each group. The mandibular second and fourth premolars on both sides of the 3 beagles were extracted. Eight weeks after extraction, 4 bone-level implant fixtures, 2 on both sides of each mandible, were placed in each beagle. Six weeks after implant surgery, healing abutments were connected. After sufficient osseointegration, plaque control was performed in the control group, while periodontitis and apical periodontitis were induced in the experimental groups. The beagles were euthanized for histological analyses 20 weeks after induction of experimental periodontitis. Statistical analyses were performed using the Kruskal-Wallis test with the Bonferroni correction to compare the 3 groups. Results: The implants in the control and apical periodontitis groups were well-maintained, while those in the periodontitis group showed clinical signs of inflammation with bone resorption. The bone-to-implant contact (BIC) and bone area values in the periodontitis group were lower than those in the other groups. The distance between the implant shoulder and the first BIC was significantly greater in the periodontitis group than in the control group (P<0.05). Conclusions: The presence of periodontitis in adjacent teeth can pose a risk to dental implants, potentially resulting in peri-implantitis. However, this was not observed for apical periodontitis. Within the limitations of this study, periodontal care is necessary to reduce the impact of periodontitis in adjacent teeth on osseointegrated implants.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.1
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• pp.55-74
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• 2006

The external contour of an implant can have significant effects on the load transfer characteristics and may result in different bone failure rates for different implant system. The purpose of this study was to investigate the effects of crest module shape and occlusal load direction on bone failure modes of five commercially available dental implant systems. Five different implant systems with internal connection; ITI (Model 1), Astra (Model 2), Bicon (Model 3), Friadent (Model 4), and Paragon (Model 5), comparable in size, but different in thread profile and cest module shapes, were compared using the finite element method. Conclusively, in the internal connection system of the implant-abutment connection methods, the stress-induced pattern at the supporting bone according to the abutment connection form had differenence among them, and implants with narrowing crestal module cross-sections at the top of the cortical bone created more favorable load transfer characteristics in this region. But it is considered that the future study is necessary about how this difference in the magnitude of the stress have an effect on the practical clinic.

• Journal of Periodontal and Implant Science
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• v.52 no.2
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• pp.170-180
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• 2022

Purpose: This study was conducted to assess the effect of hard and/or soft tissue grafting on immediate implants in a preclinical model. Methods: In 5 mongrel dogs, the distal roots of P2 and P3 were extracted from the maxilla (4 sites in each animal), and immediate implant placement was performed. Each site was randomly assigned to 1 of the following 4 groups: i) gap filling with guided bone regeneration (the GBR group), ii) subepithelial connective tissue grafting (the SCTG group), iii) GBR and SCTG (the GBR/SCTG group), and iv) no further treatment (control). Non-submerged healing was provided for 4 months. Histological and histomorphometric analyses were performed. Results: Peri-implant tissue height and thickness favored the SCTG group (height of periimplant mucosa: 1.14 mm; tissue thickness at the implant shoulder and ±1 mm from the shoulder: 1.14 mm, 0.78 mm, and 1.57 mm, respectively; median value) over the other groups. Bone grafting was not effective at the level of the implant shoulder and on the coronal level of the shoulder. In addition, simultaneous soft and hard tissue augmentation (the GBR/SCTG group) led to a less favorable tissue contour compared to GBR or SCTG alone (height of periimplant mucosa: 3.06 mm; thickness of peri-implant mucosa at the implant shoulder and ±1 mm from the shoulder: 0.72 mm, 0.3 mm, and 1.09 mm, respectively). Conclusion: SCTG tended to have positive effects on the thickness and height of the periimplant mucosa in immediate implant placement. However, simultaneous soft and hard tissue augmentation might not allow a satisfactory tissue contour in cases where the relationship between implant position and neighboring bone housing is unfavorable.