• The Journal of Korean Academy of Prosthodontics
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• v.46 no.2
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• pp.125-136
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• 2008

Statement of problem: Since the concept of osseointegration in dental implants was introduced by $Br{{\aa}}nemark$ et al, high long-term success rates have been achieved. Though the use of dental implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. Purpose: The aim of this retrospective study was to provide long-term data on the $Neoplan^{(R)}$ implant, which features a sandblasted and acid-etched surface and external connection. Material and methods: 96 $Neoplan^{(R)}$ implants placed in 25 patients in Yonsei University Hospital were examined to determine the effect of the factors on marginal bone loss, through clinical and radiographic results during 18 to 57 month period. Results: 1. Out of a total of 96 implants placed in 25 patients, two fixtures were lost, resulting in 97.9% of cumulative survival rate. 2. Throughout the study period, the survival rates were 96.8% in the maxilla and 98.5% in the mandible. The survival rates were 97.6% in the posterior regions and 100% in the anterior regions. 3. The mean bone loss for the first year after prosthesis placement and the mean annual bone loss after the first year for men were significantly higher than that of women (P<0.05). 4. The group of partial edentulism with no posterior teeth distal to the implant prosthesis showed significantly more bone loss compared to the group of partial edentulism with presence of posterior teeth distal to the implant prosthesis in terms of mean bone loss for the first year and after the first year (P<0.05). 5. The mean annual bone loss after the first year was more pronounced in posterior regions compared to anterior regions (P<0.05). 6. No significant difference in marginal bone loss was found in the following factors: jaws, type of prostheses, type of opposing dentition, and submerged /non-submerged implants (P<0.05). Conclusion: On the basis of these results, the factors influencing marginal bone loss were gender, type of edentulism, and location in the arch, while the factors such as arch, type of prostheses, type of opposing dentition, submerged / non- submerged implants had no significant effect on bone loss. In the present study, the cumulative survival rate of the $Neoplan^{(R)}$ implant with a sandblasted and acid-etched surface was 97.9% up to a maximum 57-month period. Further long-term investigations for this type of implant system and evaluation of other various domestic implant systems are needed in future studies.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.240-246
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• 2009

Statement of problem: Insertion of endosseous implants in the atrophic maxilla is often complicated because of lack of supporting bone. Augmentation of the floor of the maxillary sinus with autogenous bone & bone substitute graft has been proven to be a reliable treatment modality, at least in the short term. The aim of this study is to evaluate the factors of implant survival rate associated with maxillary sinus lift with grafts. Material and methods: The sinus floor was augmented with bone grafts derived from modified Caldwell-luctechnique(71 subject, 93 sinus, 180 implants), the autogenous bone or autogenous+Bio-oss. Before implant installation the width and height of the alveolar crest were increased in the first stage procedure in 10 patients while in the other 61 patients augmentation and implant installation could be performed simultaneously width and height of the alveolar crest > 4 mm) or delayed installation. Results: In all case bone volume was sufficients for implant insertion. 14 of 180 inserted implants were lost during follow up and the healing period Patient received implant supported overdenture(5 patients) or fixed bridge(62 patients). Conclusion: Within the limit of the result of this study, we conclude that bone grafting of the floor of the maxillary sinus floor with bone for the insertion of implants might be a reliable treatment modality and the autogenous bone graft and delayed installation method might be the factors for good results.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.280-285
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• 2016

Mandible defects could be caused by congenital malformations, trauma, osteomyelitis, tumor resection. If large areas are included for reconstruction, those are primarily due to tumor resection defects. The large jaw defect results in a problem about mastication, swallowing, occlusion and phonetics, and poor esthetics causes a lot of inconvenience in daily life. It is almost impossible to be a part underwent mandibular resection completely reproduced, should be rebuilt artificially. This case is of a patient who was diagnosed with squamous cell carcinoma pT1N0M0, stage I in February 2004 and received surgery (combined mandibulectomy and neck dissection operation (COMMANDO) in oromaxillofacial surgery) in March 2004, by implant assisted removable partial denture. We could obtain good retention and stability through sufficient coverage and implant holding. Follow up period was about four years. Mandibular left third molar regions have been observed to have resorption of surrounding bone, and periodic check-ups are necessary conditions.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.1
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• pp.54-63
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• 2024

The long-term use of an implant overdenture shows problems, such as wear of attachment, concentrated occlusal forces on the anterior teeth, fracture of artificial teeth and rotation of denture. By transitioning to an Implant-assisted removable partial denture (IARPD) using additional implant placement, the problems can be solved. In this case report, a transition was made from implant overdenture to IARPD utilizing surveyed crowns to distribute occlusal forces concentrated on anterior teeth and to prevent denture rotation in a skeletal Class III patient. Design of definitive prosthesis with appropriate function and aesthetics was determined through several stages of provisional restorations. In this case, appropriate posterior occlusion and maintenance of peri-implant bone level of definitive prosthesis were observed.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.2
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• pp.316-322
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• 2001

Chemotherapy and radiotherapy used on pediatric oncology patients often causes dentofacial anomalies. Defects noted include tooth and root agenesis, root thinning, root shortening, localized enamel defect and maxillofacial underdevelopment. The effect of radiotherapy usually is confined to the radiation site but the effect of chemotherapy may be more wide spread becuase of its systemic distribution. Many pediatric cancers are treated with a combination of radiation and multiagent chemotherapy. Dental treatment affected by chemotherapy and radiation therapy damage to developing teeth and maxilloface includes retention of teeth, space maintenance, prosthetic considerations, requirements for oral hygiene. The following case related to multiple rootless teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.2
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• pp.150-156
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• 2015

As dental implant treatment becomes popular for both partial and complete edentulous patients, old people with complex systemic diseases also tend to prefer implant-assisted-overdenture or implant-supported-fixed prostheses to conventional complete denture. In this case, 77-year-old female who was on medication for hypertension and osteoporosis and paralyzed on right side due to stroke visited for implant-assisted-overdenture on lower jaw. After oral and radiographic examination, root-assisted magnet overdenture on upper jaw and implant-assisted magnet overdenture on lower jaw are planned. Consequently, overdentures using self-adjusting magnetic attachment(SA) system on both jaws resulted in recovering satisfying function and retention, which is enable to insert and remove with only one hand.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.4
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• pp.349-360
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• 2009

Purpose: As the esthetic demands of dental implant patients are increased, the demands of zirconia as implant abutment material are also increased. It has non-metalic color, good biocompatibility, high strength and high toughness. Even thought the advatage of zirconia abutment, there are a few studies about mechanical properties of zirconia abutment. This study evaluated the mecanical strength with compressive bending strength and endurance limit of implant-zirconia abutment assembly. Materials and Methods: Static and cyclic loading of implant-Zirconia abutment assembly were simulated under worst case condition according to ISO. Test groups were implants of external butt joint with straight regular diameter and angled regular diameter zirconia abutment, implant of external butt joint with narrow straight diameter zirconia abutment and implant of internal conical joint with straight narrow diameter zirconia abutment. All test group were evaluated the mecanical strength with compressive bending strength and endurance limit. After fatique testing, fracture surface were examined by SEM. Results: The compressive bending strengths exceed 927N. Regular diameter zirconia abutment were stronger than narrow diameter zirconia abutment(P<.05). The endurance limits ranged from 503N to 868N. Conclusion: Within the limitation of this study, zirconia implant abutment exceeded the estabilished values for maximum incisal biting forces reported in the literature.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.337-349
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• 2008

Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in delayed loading conditions. A total of 36 solid screw implants (diameter 3.75 mm, length 10mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium Implants served as control. Gold crowns were inserted 3 months. Radiographic assessments and stabilitytests were performed at the time of fixture installation, $2^{nd}$ stage surgery, 1 and 3 months after loading. Histological observations and morphometrical measurements were also performed. Of 36 implants, 32 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels (p=0.413) and RFA values. The mean BIC % in the Mg-implants was $54.4{\pm}20.2%$. The mean BIC % in the turned implant was $48.9{\pm}8.0%$. These differences between the Mg-implant and control implant were not statistically significant (P=0.264). In the limitation of this study, bone-to-implant contact (BIC) and bone area of Mg-incorporated oxidized implant were similar to machine-turned implant. The stability analysis showed no significantly different ISQ values and marginal bone loss between two groups. Considering time-dependent bone responses of Mg-implant, it seems that Mg-implants enhanced bone responses in early loading conditions and osseointegrated similarly to cp Ti implants in delayed loading conditions. However, further investigations are necessary to obtain long-term bone response of the Mg-implant in human.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.97-109
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• 2022

Purpose: This study aims to investigate the risk indicators contributing to implant failure, and analyze the relationship between risk indicators and marginal bone loss (MBL) through long-term follow-up over 3 years. Materials and Methods: From 2003 to 2017, patients' medical charts with a history of dental implant surgery at Chonnam National University Dental Hospital were reviewed retrospectively. The patient's demographic variables, and clinical variables were recorded. Periapical radiographs were used to evaluated the changes in MBL around implants. And we analyzed implant survival rates. Multiple regression analysis with backward elimination was conducted to correlate the patient's clinical variables and implant failure and Pearson correlation analysis was performed to the correlated between implant long-term survival rates and MBL and initial stability. Results: In multiple regression analysis, there was a statistically significant negative correlation between abutment connection type (β = -.189, P < .05), with or without SPT (β = -.163, P < .05), diabetes (β = -.164, P < .05), osteoporosis (β = -.211, P < .05) and MBL. Anticoagulant medication influenced the long-term success rate of implants. PTV values at the second implant surgery showed a statistically significant negative correlation with long-term implant survival (P < .05). Conclusion: For the long-term success of the implant, the appropriate abutment connection type must be selected and the periodic SPT is recommended. Systemic diseases such as diabetes and osteoporosis and anticoagulant medication should be considered. Furthermore, since high PTV at the second implant surgery correlated with the long-term survival rates of the implant, initial stability should be carefully considered before undergoing the prosthetic procedure.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.1
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• pp.32-44
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• 2023

Purpose: The purpose of this study was to investigate the effect of implant connection type on marginal bone loss (MBL) and to analyze the factors that affect MBL. This study focuses on single implants planted in the upper and lower first molar area. Materials and Methods: A total of 87 implants from 68 patients were tracked for a period over 5 years. There were 57 external connection type (EC) implants and 30 internal connection type (IC) implants in 38 males and 30 females. The MBL and EA were measured from intraoral radiograph images taken after 5 years at most. Results: Significant difference in MBL between EC and IC type was observed in patients without GBR or diabetes. Patients without GBR exhibited an MBL of -0.065 ± 0.859 mm in EC type and -0.627 ± 0.639 mm in IC type (P = 0.025). Using multiple regression analysis, a statistically significant negative correlation was observed between MBL and conditions including implant-abutment connection type (β = -0.303), diabetes (β = -0.113), emergence angle > 30° (β = -0.234), and age (β = -0.776). Conclusion: Within this results, IC type implants had less MBL than EC type, and implant prosthesis with emergence angle over 30° showed greater MBL. To minimize the MBL of the implant and ensure implant stability, careful consideration should be given to the EA of implant prosthesis and its connection type.