• The Journal of the Korean dental association
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• v.56 no.5
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• pp.263-276
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• 2018

Long-term survival and prognosis of narrow-diameter implants have been reported to be adequate to consider them a safe method for treating a deficient alveolar ridge. The objective of this study was to perform case report of narrow-diameter implants with a trapezoid-shape in anterior teeth alveolar bone. A 50-year-old male patient presented with discomfort due to mobility of all of the maxillary teeth and mandibular incisors. Due to destruction of alveolar bone, four anterior mandibular teeth were extracted. Soft tissue healing was allowed for approximately 3 months after the extraction, and a new design of implant placement was planned for the mandibular incisor area, followed by clinical and radiological evaluation. Implant placement was determined using an R2GATE surgical stent. The stability of the implants was assessed by ISQ measurements at the first and second implant surgery and after prosthetic placement. At 1 and 3 months and 1 year after implantation of the prosthesis, clinical and radiological examinations were performed. Another 50-year-old male patient presented with discomfort due to mobility of the mandibular central incisors. For the same reason as in the first patient, implant placement was carried out in the same way after extraction. ISQ measurements and clinical and radiological examinations were performed as in the previous case. In these two clinical cases, 12 months of follow-up revealed that the implant remained stable without inflammation or additional bone loss, and there was no discomfort to the patient. In conclusion, computer-guided implant surgery was used to place an implant in an optimal position considering the upper prosthesis. A new design of a narrow-diameter implant with a trapezoid-shape into anterior mandibular alveolar bone is a less invasive treatment method and is based on the contour of the deficient alveolar ridge. Through all of these procedures, we were able to reduce the number of traumas during surgery, reduce the operation time and total treatment period, and provide patients with more comfortable treatment.

• Journal of Periodontal and Implant Science
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• v.50 no.2
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• pp.97-105
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• 2020

Purpose: The present retrospective clinical study aimed to evaluate and compare the clinical and radiographic parameters, complications, and satisfaction in patients who received fixed prostheses supported by narrow-diameter implants (NDIs) in the anterior and posterior jaw. Methods: Patients aged ≥30 years who had NDI-supported fixed prostheses in the anterior or posterior region of either jaw for at least 2 years were included. Complications such as chipping of the crown; loosening or fracture of the screw, crown abutment, or implant; and loss of retention were recorded. Clinical peri-implant outcomes and crestal bone loss (CBL) were measured. A questionnaire was used to record responses regarding the aesthetics and function of the fixed restorations. Analysis of variance was used to assess the significance of between-group mean comparisons. The log-rank test was performed to analyze the influence of location and prosthesis type on technical complications. Results: Seventy-one patients (mean age: 39.6 years) provided informed consent with a mean follow-up duration of 53 months. Only bleeding on probing showed a statistically significant difference between NDIs in the anterior and posterior regions. The complication rate for NDIs in the posterior region was significantly higher than that for NDIs in the anterior region (P=0.041). For NDIs, CBL was significantly higher around splinted crowns than single crowns (P=0.022). Overall mean patient satisfaction was 10.34±3.65 on a visual analogue scale. Conclusions: NDIs in the anterior and posterior jaws functioned equally well in terms of periimplant soft and hard tissue health and offered acceptable patient satisfaction and reasonable complication rates.

• 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 the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.4
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• pp.325-330
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• 2010

Introduction: Mini-implant system is applicable to areas of narrow space and area requiring temporary loading support. The purpose of this study was to evaluate the clinical outcome of a mini-implant system as well as the application of mini-implant system in the dental clinical field. Materials and Methods: The patients who had been operated from Jan 2007 to Dec 2007 in the four dental facility including Seoul National University Bundang Hospital were enrolled. To evaluate the factors associated with the clinical outcome, the patients were classified according to gender, age, area of surgery, type of implant, diameter and length of the implant, and the purpose of the mini-implant system application. Results: From 147 implants, only three implants failed, one of them was for temporary loading. There were no serious surgical or prosthetic complications in this study. Conclusion: An analysis of the preliminary data revealed a satisfactory clinical outcome. However, more long-term evaluation of narrow ridge type as well as the patient’s satisfaction on the use of a provisional type mini-implant system is needed.

• The Journal of Advanced Prosthodontics
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• v.8 no.4
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• pp.304-312
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• 2016

PURPOSE. The aim of this study was to investigate the stress distribution of 2-short implants (2SIs) installed in a severely atrophic maxillary molar site. MATERIALS AND METHODS. Three different diameters of internal connection implants were modeled: narrow platform (NP), regular platform (RP), and wide platform (WP). The maxillary first molars were restored with one implant or two short implants. Three 2SI models (NP-oblique, NP-vertical, and NP-horizontal) and four single implant models (RP and WP in a centered or cantilevered position) were used. Axial and oblique loadings were applied on the occlusal surface of the crown. The von Mises stress values were measured at the bone-implant, peri-implant bone, and implant/abutment complex. RESULTS. The highest stress distribution at the bone-implant interface and the peri-implant bone was noticed in the RP group, and the lowest stress distribution was observed in the 2SI groups. Cantilevered position showed unfavorable stress distribution with axial loading. 2SI types did not affect the stress distribution in oblique loading. The number and installation positions of the implant, rather than the bone level, influenced the stress distribution of 2SIs. The implant/abutment complex of WP presented the highest stress concentration while that of 2SIs showed the lowest stress concentration. CONCLUSION. 2SIs may be useful for achieving stable stress distribution on the surrounding bone and implant-abutment complex in the atrophic posterior maxilla.

• The Journal of the Korean dental association
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• v.46 no.4
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• pp.243-247
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• 2008

Purpose : Ridge expansion osteotomy (REO) has been introduced when it is necessary to expand narrow crestal ridge with simultaneous implant placement. This study has designed to evaluate the clinical availability of REO. Materials and methods : Subject were patients who had visited Seoul National University Bundang Hospital from July. 2003 to December, 2005 for implant placement using REO by one surgeon. Intraoperative and postoperative complication, failure of initial osseointegration and marginal bone resorption were estimated using electronic medical record and periapical radiography. Twenty?three patients, 8 males and 15 females, mean age 51, ranged 18 to 72, were treated for mean 26 months, ranged from 16 months to 46 months. Results : Mean diameter and length of implants placed at upper anterior, were 3.72mm and 13.32mm each other. Guided bone regeneration and ridge splitting were accompanied in this study. Five cases of cortical bone fracture, three cases of crestal bone loss more than 2mm, 2cases of gingival recession, and 2 cases of infection were noted, but there were no implants removed because of disintegration. Success rate of implant was 91.7%, even if survival rate of implant was 100%. In addition, there were no statistical significance between the success rate of REO and bone graft(p>0.05). Conclusion : Based on the results of the present study, it can be concluded that REO technique is reliable for implant placement at atrophic ridge with adequate height compared to bone graft and other osteotomies for ridge expansion, but care should be taken of esthetic problem such as gingival recession because of crestal bone resorption from trauma by osteotome.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.1
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• pp.119-126
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• 2022

Mini-implant has been reported as an alternative method to conventional diameter implants in the treatment of mandibular anterior region with narrow ridge. However, one-piece type mini-implant showed biological and technical complications, such as peri-implantitis by residual cement and prosthetic detachment. Recently, one-piece type mini-implant with additional retentive structure has been introduced to increase the retention and stability of the mini-implant. The mini-implant is based on spreading the upper retentive structure with a spreader and connected it with the inner surface of the zirconia prosthesis. In two cases, we tried to reduce these complications through the mini-implant on the narrow mandibular anterior region, and it was possible to reduce the overall treatment period through a digital system. In this case report, restoration using the digital mini-implant system showed improvement of patient satisfaction on the aspect of function and esthetic in the narrow mandibular anterior region.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.6
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• pp.579-585
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• 2006

Introduction: The fibular free flap is now considered as the first choice for long mandibular discontinuity defect. In spite of its good bone quality for implant installation, its diameter is too narrow to rehabilitate the masticatory function with implant installation. In this report, distraction osteogenesis was used for the augmentation of bone to install the dental implant in the mandible which was reconstructed with a vascularized fibular free flap. Patients and Methods: Three patients undertook the vertical augmentation of grafted fibular bone and dental implants were installed. On the day 8 post-surgery, the activation of the distractor was started at the rate of 1 mm twice a day. The total amount of distraction was 15 mm in two patients and 12.5 mm in one patient. Twelve implants were installed in three patients. Dental implants were simultaneously installed during removal of the distraction device in two patients. In one patient, the implant installation was delayed after device had been removed. All three patients showed the symptoms of mild to severe postoperative infection during the activation and consolidation. However, the distracted site showed undisturbed bone regeneration. Conclusion: The distraction osteogenesis showed the reliable results for the vertical augmentation of fibular bone which was used for the mandibular reconstruction. However, the great tendency of postoperative infection must be considered and clinically controlled.