• The Journal of Advanced Prosthodontics
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• v.13 no.6
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• pp.396-407
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• 2021

PURPOSE. Zirconia has exceptional biocompatibility and good mechanical properties in clinical situations. However, finite element analysis (FEA) studies on the biomechanical stability of two-piece zirconia implant systems are limited. Therefore, the aim of this study was to compare the biomechanical properties of the two-piece zirconia and titanium implants using FEA. MATERIALS AND METHODS. Two groups of finite element (FE) models, the zirconia (Zircon) and titanium (Titan) models, were generated for the exam. Oblique (175 N) and vertical (175 N) loads were applied to the FE model generated for FEA simulation, and the stress levels and distributions were investigated. RESULTS. In oblique loading, von Mises stress values were the highest in the abutment of the Zircon model. The von Mises stress values of the Titan model for the abutment screw and implant fixture were slightly higher than those of the Zircon model. Minimum principal stress in the cortical bone was higher in the Titan model than Zircon model under oblique and vertical loading. Under both vertical and oblique loads, stress concentrations in the implant components and bone occurred in the same area. Because the material itself has high stiffness and elastic modulus, the Zircon model exhibited a higher von Mises stress value in the abutments than the Titan model, but at a level lower than the fracture strength of the material. CONCLUSION. Owing to the good esthetics and stress controllability of the Zircon model, it can be considered for clinical use.

• The korean journal of orthodontics
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• v.52 no.6
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• pp.412-419
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• 2022

Objective: This study evaluated the effect of cyclic pre-calcification treatment on the improvement of bioactivity and osseointegration of Ti-6Al-4V mini-screws. Methods: The experimental groups were: an untreated group (UT), an anodized and heat-treated group (AH), and an anodized treatment followed by cyclic pre-calcification treatment group (ASPH). A bioactive material with calcium phosphate was coated on the mini-screws, and its effects on bioactivity and osseointegration were evaluated in in vitro and in vivo tests of following implantation in the rat tibia. Results: As a result of immersing the ASPH group in simulated body fluid for 2 days, protrusions appearing in the initial stage of hydroxyapatite precipitation were observed. On the 3rd day, the protrusions became denser, other protrusions overlapped and grew on it, and the calcium and phosphorus concentrations increased. The removal torque values increased significantly in the following order: UT group (2.08 ± 0.67 N·cm), AH group (4.10 ± 0.72 N·cm), and ASPH group (6.58 ± 0.66 N·cm) with the ASPH group showing the highest value (p < 0.05). In the ASPH group, new bone was observed that was connected to the threads, and it was confirmed that a bony bridge connected to the adjacent bone was formed. Conclusions: In conclusion, it was found that the surface treatment method used in the ASPH group improved the bioactivity and osseointegration of Ti-6Al-4V orthodontic mini-screws.

• Archives of Craniofacial Surgery
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• v.24 no.2
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• pp.52-58
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• 2023

Background: Complex orbital fractures are impure orbital fractures because they involve the orbital walls and mid-facial bones. The author reported an orbital wall restoration technique in which the primary orbital wall fragments were restored to their prior position in complex orbital fractures in 2020. As a follow-up to a previous preliminary study, this study retrospectively reviewed the surgical results of complex orbital wall fractures over a 4-year period and compared the surgical outcomes by dividing them into groups with and without balloon restoration. Methods: Data of 939 patients with facial bone fractures between August 2018 and August 2022 were reviewed. Of these, 154 had complex orbital fractures. Among them, 44 and 110 underwent reduction with and without the balloon technique respectively. Pre- and postoperative Naugle exophthalmometer (Good-Lite Co.) scales were evaluated. The orbital volume and orbital volume ratio were calculated from preoperative and 6 months postoperative computed tomography images. Results: Among 154 patients with complex orbital fractures, 44 patients underwent restoration with the balloon technique, and 110 patients underwent restoration without it. The Naugle scale did not differ significantly between the two groups, but the orbital volume ratio significantly decreased by 3.32% and 2.39% in groups with and without the balloon technique and the difference in OVR was significantly greater in patients in the balloon restoration group compared with the control group. Postoperative balloon rupture occurred in six out of 44 cases (13.64%). None of the six patients with balloon rupture showed significant enophthalmos at 6 months of follow-up. Conclusion: The balloon rupture rate was 13.64% (6/44 cases) with marginal screw fixation, blunt screws, and extra protection with a resorbable foam dressing. Furthermore, we restored the orbital wall with primary orbital fragments using balloon support in complex orbital wall fractures.

• Hip & pelvis
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• v.36 no.1
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• pp.12-25
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• 2024

Protrusio acetabuli, or abnormal protrusion of the femoral head into the acetabulum, requires performance of a total hip arthroplasty (THA) for which various reconstruction techniques and outcomes have been described. The aim of this systematic review is to provide a comprehensive analysis of the current evidence, evaluate treatment efficacy, compare surgical techniques, and identify topics for future research along with improving evidence-based decision-making, improving patient outcomes in the management of this condition. A thorough systematic review of the PubMed, Embase, Cochrane Library databases, and Scopus library was conducted, and articles describing techniques of THA for treatment of protrusion acetabuli were extracted. The initial search generated 751 results. After exclusion, 18 articles were included. Of these, eight were prospective studies and 10 were retrospective. Surgery was performed on 783 hips with a mean age of 60 years; 80% of females who mostly had inflammatory arthritis were followed up for 8.86 years (range, 2-15.4 years). Good outcomes have been achieved with THA using uncemented cups with bone graft; however, no conclusion could be drawn with regard to the femoral side. It can be concluded that the concept of restoration of the anatomical hip center of rotation is paramount for good outcome and better survival of the implant is important when using uncemented cups with a bone graft. In addition, screw augmentation for fixation is not recommended unless absolutely necessary. The most common complications were aseptic loosening and heterotopic ossification. While the former required revision, conservative management was administered for the latter.

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.2
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• pp.128-133
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• 2004

Purpose: This study was planned to evaluate complications? of posterior cruciate ligament (PCL) reconstruction with tibial inlay technique using autogenous bone-patellar tendon-bone graft. Materials and Methods: From September 1994 to January 2004, we analyzed surgical complications in fifty-seven patients with fifty-eight cases who underwent PCL reconstruction. Fifty of them were male and seven female. The mean age of the patients was 35(15$\~$73). Twenty eight cases of injury were isolated PCL, while thirty cases had associated injury of knee. The causes of injury were thirty-nine cases of traffic accident, seven sport injuries, seven fall down injuries, and five of others. The follow-up study was done at 4 weeks, 3 months,6 months and 1 year after surgery. KT-2000 arthrometer and posterior stress X-ray were used to examine the stability of the knee joint and the Lysholm Knee Score and a variety of clinical complications were evaluated. Results: Although the mean score of the preoperative Lysholm Knee Score was 43.2, the postoperative score was increased to 87.9. The preoperative mean value of knee stability using KT-2000 arthrometer was 8.75 mm(6.2$\~$14.3 mm) but the postoperative mean was 3.41 mm(2.1$\~$10.6 mm). The intraoperative complications were: one case of popliteal artery injury with compartment syndrome, one case of patellar fracture, two cases of 20$^{\circ}$ flexion loss, and two cases of anterior cortical penetration of the screw through proximal tibia during screw fixation. The postoperative complications were: eleven cases of knee instability, one case of patellar fracture, five cases of extension loss, thirteen cases of flexion loss, twenty-one cases of around knee pain and eight cases of kneeling pain. Conclusion: After PCL reconstruction with tibial inlay technique using autogenous bone-patella tendon-bone graft, complications were observed in this study. Careful attention during and after the operation, as well as rehabilitation must be required.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.3
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• pp.341-349
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• 2008

Purpose: The purpose of this study was to evaluate the $Osstem^{(R)}$ implants (US II/SS II implants) through the retrospective study for the clinical success rate during the installation of the $Osstem^{(R)}$ implants (US II/SS II implants) by using of the procedures of maxillary sinus floor elevation. Materials and methods: The current study was researched in the 6 medical institutions: Chonnam National University, Chosun University, Pusan DaeDong Hospital, Bundang Seoul National University Hospital, Ap-Seon Clinic, and All Clinic. Based on the total number of 116 patients whose treatment was the installation of the US II/SS II implants with the procedures of the maxillary sinus floor elevation, they were conferred on the dental records of the patients under the joint consultation of the 6 medical institutions. On the dental recording charts, there were included in as the following; the name of the institutions, gender, age, with or without smoking or drinking, with or without the generalized diseases, the height of the alveolar bone on the operational sites, elapsed edentulous state period, the state of the opposed or adjacent teeth, the methods of the maxillary sinus floor elevation, secondary time period for surgery, the lengths, types, and diameters of implants, with or without bone transplantation or the types of bone, postoperative current bone height, current adjacent soft tissue state of the implants, with or without the success of the installations of the implants. We have done our survey with the clinical and radiolographical examinations and dental questionaries. The success and survival rate of the implants was evaluated. Results 1. Total number of the patients with the installation of the US II implants were 62. The 252 numbers of US II implants were installed on the 89 maxillary sinuses. The patient's mean age was 54.1 years old and there were 36 men and 27 women. 2. Total number of patients with the installation of SS II implant were 57. The 165 numbers of SS II implants were planted on the 80 maxillary sinuses. Their mean age was 48.7 years old and there were 37 men and 20 women. 3. The follow-up period was 30.7 months(21-49 mon) on average. The vertical bone loss of installed implants after the procedures of the maxillary sinus elevation was 1.1 mm on average in SS II and 1.3 mm on average in US II. There existed no statistical significance on each group. The mean enlarged bone height after the maxillary sinus floor elevation was 8.2 mm. 4. For the procedures of the maxillary sinus elevation, the Lateral approach technique occupied 87.1%, which was the most used one. In addition, the most frequently used transplanted bone was autogenous bone only which was 72.7% during the maxillary sinus floor elevation. 5. The complication of maxillary sinus floor elevation were perforation of sinus membrane, disesthesia on doner site, exposure of cover screw and exposure of maxillar bone. 6. The survival rate of US II and SS II after maxillary sinus floor elevation was 99.2% and 95.8%, respectively. And the success rate of US II and SS II after maxillary sinus floor elevation was 97.6% and 89.7%, respectively. Conclusion : On the evaluation of the analysis of our study, both US II and SS II implants showed the excellent clinical results by use of the procedures of maxillary sinus floor elevation.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.4
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• pp.301-311
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• 2011

Introduction: This study examined the effect of the application of low intensity pulsed ultrasound on bone healing after an injection of adipose tissue-derived stem cells (ADSCs) during the implantation of a titanium implant in the tibia of diabetes-induced rats. Materials and Methods: Twelve Sprague-Dawely rats were used. After inducing diabetes, the ADSCs were injected into the hole for the implant. Customized screw type implants, 2.0 mm in diameter and 3.5 mm in length, were implanted in both the tibia of the diabetes-induced rats. After implantation, LIPUS was applied with parameters of 3 MHz, 40 mW/$cm^2$, and 10 minutes for 7 days to the left tibiae (experimental group) of the diabetesinduced rats. The right tibiae in each rat were used in the control group. At 1, 2 and 4 week rats were sacrificed, and the bone tissues of both tibia were harvested. The bone tissues of the three rats in each week were used for bone-to-implant contact (BIC) and bone area (BA) analyses and the bone tissues of one rat were used to make sagittal serial sections. Results: In histomorphometric analyses, the BIC in the experimental and control group were respectively, $39.00{\pm}18.17%$ and $42.87{\pm}9.27%$ at 1 week, $43.74{\pm}6.83%$ and $32.27{\pm}6.00%$ at 2 weeks, and $32.62{\pm}11.02%$ and $47.10{\pm}9.77%$ at 4 weeks. The BA in experimental and control group were respectively, $37.28{\pm}3.68%$ and $31.90{\pm}2.84%$ at 1 week, $20.62{\pm}2.47%$ and $15.64{\pm}2.69%$ at 2 weeks, and $11.37{\pm}4.54%$ and $17.69{\pm}8.77%$ at 4 weeks. In immunohistochemistry analyses, Osteoprotegerin expression was strong at 1 and 2 weeks in the experimental group than the control group. Receptor activator of nuclear factor kB ligand expression showed similar staining at each week in the experimental and control group. Conclusion: These results suggest that the application of low intensity pulsed ultrasound after an injection of adipose tissue-derived stem cells during the implantation of titanium implants in the tibia of diabetes-induced rats provided some positive effect on bone regeneration at the early stage after implantation. On the other hand, this method is unable to increase the level of osseointegration and bone regeneration of the implant in an uncontrolled diabetic patient.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.206-214
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• 2003

Purpose : To analysis each clinical results after arthroscopic ACL reconstruction with using variable fixatives which are metallic and bioabsorbable interference screw, and RIGIDfix. Therefore, We reported the clinical reliability and safty of ACL reconstruction using RIGIDfix. Materials and Methods : We evaluated the results of arthroscopic ACL resconstruction with patellar tendon autograft among three groups, of which group 1 is used metal interference screw for 44 patients, group 2 used bioabsorbable interference screw for 47 patients, group 3 used RIGIDfix for 42 patients. We compared the clinical results by physical examination (anterior drawer test, Lachman test and pivot shift test), Lysholm score and KT-2000 arthrometer and compared the radiological results by measurement of tunnel and fixatives position and widening and by MRI findings. We analyzed the results by SAS 8.2 Ducan. Tukey and paired t-test Results : Physical instability was in 5 cases, which group 2 had 4 cases and group 3 had 1 case. Lysholm score improved from 59.8. 64.4, 61 to 90.1, 92.3. 92. KT-2000 arthrometer instability improved from 9.20, 10.2, 9.5 to 1.43. 1.62. 2.00 (p=0.478). Radiologically, all cases had excellent tunnel position and cyst change was observed the 8 cases in the group 2, but, all 20 cases 2nd MRI had signal change of peri-fixatives. But, no correlation of clinical results. Conclusion : No statistical difference of clinical instability was found among three groups. And femoral tunnel changes were much observed in group I, II than III. We considered the RIGIDfix has much advantages because the short operation time, better fixation position and much bone contact surface. But, further long term follow up study was needed.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.36 no.5
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• pp.219-223
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• 2014

During surgical procedures, unexpected material, including surgical instruments and tissue segments, may get lost in the surgical field. Most of these should be immediately removed to prevent further complications, such as vital organ irritation, infection, and inflammatory pseudo-tumor formation. However, it is not always easy to define the exact location of the foreign body, especially if the item is very small and/or it is embedded in the soft tissue of the head and neck region. Intraoperative real-time radiological imaging with C-arm fluoroscopy can be useful to trace the three-dimensional location of small and embedded foreign bodies in the oral and maxillofacial area. We describe an unusual case of an embedded micro-screw in the intrinsic tongue muscle that had been dropped into the sublingual space during a lower alveolar bone graft procedure. The lost foreign body was accurately identified with C-arm fluoroscopy and safely removed without any further complications.

• Journal of Korean Foot and Ankle Society
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• v.15 no.1
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• pp.18-21
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• 2011

Purpose: To evaluate the clinical and radiological results of internal fixation with tension band wiring for the fracture at the base of fifth metatarsal bone. Materials and Methods: From January 2008 to December 2009, 15 cases with displaced fracture at the base of fifth metatarsal were analyzed and average follow up period was 13.8 months. Lawrence classification was used to classify fracture type. We evaluated clinical results by American Orthopedic Foot Ankle Society (AOFAS) midfoot score and radiological results by union time. Complications was also checked. Results: According to classification, zone I fracture were 11 cases and zone II fracture were 4 cases. Bony union was achieved in all cases after 7 weeks. In the final follow-up, average AOFAS score was 94. There were no complications except hardware irritation. Conclusion: Satisfactory results were obtained after tension band wiring for the fifth Metatarsal base fracture in zone I fracture or comminuted zone II fracture for which it is not easy to be fixed with screw.