• The Journal of Advanced Prosthodontics
• /
• v.4 no.4
• /
• pp.204-209
• /
• 2012

PURPOSE. The aim of this systematic review is to address treatment outcomes of Mandibular implant overdentures relative to implant survival rate, maintenance and complications, and patient satisfaction. MATERIALS AND METHODS. A systematic literature search was conducted by a PubMed search strategy and hand-searching of relevant journals from included studies. Randomized Clinical Trials (RCT) and comparative clinical trial studies on mandibular implant overdentures until August, 2010 were selected. Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants. RESULTS. Six studies presented the data of the implant survival rate which ranged from 95% to 100% for 2 and 4 implant group and from 81.8% to 96.1% for 1 and 2 implant group. One study, which statistically compared implant survival rate showed no significant differences relative to the number of implants. The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group, and denture repair due to the fracture around an implant for 1 and 2 implant groups. Most studies showed no significant differences in the rate of prosthetic maintenance and complication, and patient satisfaction regardless the number of implants. CONCLUSION. The implant survival rate of mandibular overdentures is high regardless of the number of implants. Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants.

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

• Journal of the Korean Society of Industry Convergence
• /
• v.26 no.4_2
• /
• pp.623-628
• /
• 2023

The purpose of this study was to evaluate the fracture strength and removal torque value (RTV) of a conventional angled abutment and a newly developed angled abutment (Beauty up abutment) with an angulated screw access hole. Each abutment was divided into a control group and an experimental group (n = 20, respectively). To measure the fracture strength, the abutment was connected to the internal hex implant with 30 Ncm torque, and a load was applied at 30 degree angle with cross-head speed of 1 mm/min using a universal testing machine according to the ISO 14801:2016 standard. To measure RTV, each abutment was fastened to the implant with 30 Ncm torque. Retightening was performed after 10 minutes, and initial RTV was measured with a digital torque gauge. After retightening, a load of 250 N was applied to the abutment at a 30 degree angle using a chewing simulator. After a total of 100,000 repeated loads, RTV was measured. Statistical analysis was performed using Wilcoxon signed rank test and Mann-Whitney U test (α = .05). The fracture strength of the experimental group was statistically significantly lower than that of the control group (P = .009). There was no significant difference between initial RTV and post-loading RTV between the experimental group and the control group (P = .753, P = .527, respectively), and cyclic loading did not significantly affect RTV in both groups (P = .078).

• Biomaterials and Biomechanics in Bioengineering
• /
• v.5 no.1
• /
• pp.37-50
• /
• 2020

Development of lightweight implant plates are important to reduce the stress shielding effect for a prosthesis of femur bone fractures. Stainless steel (SS-316L) is a widely used material for making implants. Stress shielding effect and other issues arise due to the difference in mechanical properties of stainless steel when compared with bone. To overcome these issues, composite materials seem to be a better alternative solution. The comparison is made between two biocompatible composite materials, namely Ti-hydroxyapatite and Ti-polypropylene. "Titanium (Ti)" is fiber material while "hydroxyapatite" and "polypropylene" are matrix materials. These two composites have Young's modulus closer to the bone than stainless steel. Besides the variety of bones, present paper constrained to femur bone analysis only. Being heaviest and longest, the femur is the most likely to fail among all bone failures in human. Modelling of the femur bone, screws, implant and assembly was carried out using CATIA and static analysis was carried out using ANSYS. The femur bone assembly was analyzed for forces during daily activities. Ti-hydroxyapatite and Ti-polypropylene composite implants induced more stress in composite implant plate, results less stress induced in bone leading to a reduction in shielding effect than stainless steel implant plate thus ensuring safety and quick healing for the patient.

• The Journal of the Korean dental association
• /
• v.58 no.2
• /
• pp.83-92
• /
• 2020

In the anterior maxillary area, dental implants for tooth replacement are challenging due to the need to satisfy high esthetic level as well as functionality. Immediate implant placement and provisionalization can dramatically reduce the edentulous period, and then fulfill patient's demand for esthetics. The aim of present case report is to demonstrate two cases that successfully restored single tooth with immediate implant placement and provisionalization in the anterior maxillary area. A 47 years old female was scheduled to replace her maxillary right central incisor due to crown-root fracture by trauma. Another 54-year-old female was planned to place dental implant following tooth extraction of maxillary right lateral incisor owing to continuous pus discharge despite repetitive treatments including apicoectomy. In these two cases, surgical and prosthetic procedures progressed in a similar way. After minimal flap elevation, atraumatic tooth extraction was performed. Implant was placed in proper 3-dimensional position and angulation with primary stability. Bone graft or guided bone regeneration for peri-implant bone defect was conducted simultaneously. Provisionalization without occlusal loading was carried out at the same day. Each definitive crown was delivered at 7 and 5 months after the surgery. Two cases have been followed uneventfully for 2 to 5 years of loading time. In conclusion, Immediate implant placement and provisionalization could lead to esthetic outcome for single tooth replacement with dental implant under proper case selection.

• Proceedings of the KOSOMBE Conference
• /
• v.1997 no.11
• /
• pp.337-342
• /
• 1997

Dental implant has been increasingly used to recover the masticatory unction of tooth. It has been well known that the success of dental implant is heavily dependent on initial stability and long-term osseointegration due to optimal stress distribution in the surrounding bones. The role of periodontal ligament, removed during operation, is to absorb impact force and to distribute them to alveolar bone. or this reason, the study for artificial periodontal ligament has become an important issue in this field. In this study, chitosan was coated on dental implant or the purpose of replacing the role of intact periodontal ligament. The results by experiment and FEM analysis showed : I) Initial stability of dental implant was significantly increased(35%) when the implant was coated with chitosan. II) The coated implant showed higher impact absorption, more even stress distribution and lower stress magnitude under impact force than uncoated implant. Accordingly, the micro-fracture of the surrounding bones due to impact force would be lessened by chitosan coating on dental implant.

• Journal of Korean Neurosurgical Society
• /
• v.37 no.6
• /
• pp.416-421
• /
• 2005

Objective: Despite general agreement on the goals of surgical treatment in thoracolumbar burst fractures, considerable controversy exists regarding the choice of operative techniques. This study is to evaluate the efficacy of short-segment fixation for thoracolumbar burst fractures after long-term follow-up and to analyze the causes of treatment failures. Methods: 48 out of 60 patients who underwent short-segment fixation for thoracolumbar burst fractures between January 1999 and October 2002 were enrolled in this study. Their neurological status, radiological images, and hospital records were retrospectively reviewed. Simple radiographs were evaluated to calculate kyphotic angles and percentages of anterior body compression (%ABC). Results: The average kyphotic angles were $20.0^{\circ}$ preoperatively, $9.6^{\circ}$ postoperatively, and $13.1^{\circ}$ at the latest follow-up. The average %ABC were 47.3% preoperatively, 31.2% postoperatively, and 33.3% at the latest follow-up. The treatment failure, defined as correction loss by $10^{\circ}$ or more or implant failure, was detected in 6 patients (12.5%). 5 out of 6 patients had implant failures. 2 out of 5 patients were related with osteoporosis, and the other 2 were related with poor compliance of spinal bracing. 3 patients with poor initial postoperative alignment had implant failure. 4 patients with screws only on the adjacent vertebrae and not on the injured vertebra itself showed poor initial and overall correction. Conclusion: With proper patient selection, adequate intraoperative reduction with screw fixation involving the injured vertebra, and strict postoperative spinal bracing, the short-segment fixation is an efficient and safe method in the treatment of thoracolumbar burst fracture.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.41
• /
• pp.36.1-36.8
• /
• 2019

Background: This study aims to examine the outcome of simultaneous maxillary sinus lifting, bone grafting, and vertical ridge augmentation through retrospective studies. Methods: From 2005 to 2010, patients with exhibited severe alveolar bone loss received simultaneous sinus lifting, bone grafting, and vertical ridge augmentations were selected. Fifteen patients who visited in Seoul National University Bundang Hospital were analyzed according to clinical records and radiography. Postoperative complications; success and survival rate of implants; complications of prosthesis; implant stability quotient (ISQ); vertical resorption of grafted bone after 1, 2, and 3 years after surgery; and final observation and marginal bone loss were evaluated. Results: The average age of the patients was 54.2 years. Among the 33 implants, six failed to survive and succeed, resulting in an 81.8% survival rate and an 81.8% success rate. Postoperative complications were characterized by eight cases of ecchymosis, four cases of exposure of the titanium mesh or membrane, three cases of periimplantitis, three cases of hematoma, two cases of sinusitis, two cases of fixture fracture, one case of bleeding, one case of numbness, one case of trismus, and one case of fixture loss. Prosthetic complications involved two instances of screw loosening, one case of abutment fracture, and one case of food impaction. Resorption of grafted bone material was 0.23 mm after 1 year, 0.47 mm after 2 years, 0.41 mm after 3 years, and 0.37 mm at the final observation. Loss of marginal bone was 0.12 mm after 1 year, and 0.20 mm at final observation. Conclusions: When sinus lifting, bone grafting, and vertical ridge augmentation were performed simultaneously, postoperative complications increased, and survival rates were lower. For positive long-term prognosis, it is recommended that a sufficient recovery period be needed before implant placement to ensure good bone formation, and implant placement be delayed.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2018.06a
• /
• pp.72-72
• /
• 2018

A dynamic fatigue characteristic of dental implant system has been evaluated with applying single axial compressive shear loading based on the ISO 14801 standard. For the advanced dynamic fatigue test, multi-directional force and motion needed to be accompanied for more information of mechanical properties as based on mastication in oral environment. In this study, we have prepared loading and motion protocol for the multi-directional fatigue test of dental implant system with single (Apical/Occlusal; AO), and additional mastication motion (Lingual/Facial; LF, Mesial/Distal; MD). As following the prepared protocol (with modification of ISO 14801), fatigue test was conducted to verify the worst case results for the development of highly stabilized dental implant system. Mechanical testing was performed using an universal testing machine (MTS Bionix 858, MN, USA) for static compression and single directional loading fatigue, while the multi-directional loading was performed with joint simulator (ADL-Force 5, MA, USA) under load control. Basically, all mechanical test was performed according to the ISO 14801:2016 standard. Static compression test was performed to identify the maximum fracture force with loading speed of 1.0 mm/min. A dynamic fatigue test was performed with 40 % value of maximum fracture force and 5 Hz loading frequency. A single directional fatigue test was performed with only apical/occlusal (AO) force application, while multi directional fatigue tests were applied $2^{\circ}$ of facial/lingual (FL) or mesial/distal (MD) movement. Fatigue failure cycles were entirely different between applying single-directional loading and multi-directional loading. As a comparison of these loading factor, the failure cycle was around 5 times lower than single-directional loading while applied multi-directional loading. Also, the displacement change with accumulated multi-directional fatigue cycles was higher than that of single directional cycles.

• Clinics in Shoulder and Elbow
• /
• v.5 no.1
• /
• pp.23-28
• /
• 2002

Purpose Displaced lateral end fracture of clavicle and acromioclavicular dislocation type Ⅲ∼Ⅵ may be required surgical treatment. Material and Methods : From May 1998 to March 2001, we operated with Welter plate with minimal incision by one surgeon. Immediately, pendulum and passive exercise was initiated after surgery. The shoulder function was evaluated using UCLA score. Average follow up was on 28(12∼45) months. Results : All 11 patients were regained satisfactory function. Average UCLA score was 31.9(29~35) at last follow up. Conclusion . The merit of Welter plate fixation with minimal incision is simple technique, reduced surgical time, smaller scar than large plate, strong fixation, early exercise, reduced implant failure. The disadvantage is expensive, skin irritatatation by long hook. But Welter plate fixation with minimal incision is a good method of internal fixation and excellent clinical result in surgical treatment of type H displaced lateral end fracture of the clavicle and type Ⅲ∼Ⅵ acromioclavicular dislocation.