• Hip & pelvis
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• v.36 no.2
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• pp.87-100
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• 2024

Total hip arthroplasty (THA) is an effective treatment for osteoarthritis, and the popularity of the direct anterior approach has increased due to more rapid recovery and increased stability. Instability, commonly caused by component malposition, remains a significant concern. The dynamic relationship between the pelvis and lumbar spine, deemed spinopelvic motion, is considered an important factor in stability. Various parameters are used in evaluating spinopelvic motion. Understanding spinopelvic motion is critical, and executing a precise plan for positioning the implant can be difficult with manual instrumentation. Robotic and/or navigation systems have been developed in the effort to enhance THA outcomes and for implementing spinopelvic parameters. These systems can be classified into three categories: X-ray/fluoroscopy-based, imageless, and computed tomography (CT)-based. Each system has advantages and limitations. When using CT-based systems, preoperative CT scans are used to assist with preoperative planning and intraoperative execution, providing feedback on implant position and restoration of hip biomechanics within a functional safe zone developed according to each patient's specific spinopelvic parameters. Several studies have demonstrated the accuracy and reproducibility of robotic systems with regard to implant positioning and leg length discrepancy. Some studies have reported better radiographic and clinical outcomes with use of robotic-assisted THA. However, clinical outcomes comparable to those for manual THA have also been reported. Robotic systems offer advantages in terms of accuracy, precision, and potentially reduced rates of dislocation. Additional research, including conduct of randomized controlled trials, will be required in order to evaluate the long-term outcomes and cost-effectiveness of robotic-assisted THA.

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.196-204
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• 1994

The purpose of this clinical trial was to study the effectiveness of 5% potassium nitrate dentifrice as a daily home treatment of dentinal hypersensitivity. Thirty subjects with dentinal hypersensitivity were included in a 4-week, double-blind, parallel, comparative study. Stimuli used included mechanical, cold water and compressed air blasts. A subjective assessment of the degree of hypersensitivity for each stimulus was recorded. The results indicated that 5% potassium nitrate dentifrice, in comparision with a conventional fluoride dentifrice, reduced dentinal hypersensitivity to a significant degree. The therapeutic response to potassium nitrate was apparent within 2 weeks and increased continuously for the length of the study period. We conclude that 5% potassium nitrate dentifrice is an effective agent for the daily home treatment of dentinal hypersensitivity.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.847-852
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• 2014

As the scaling trend becomes accelerated in process technology for cost reduction in semiconductor chip manufacturing, the requirement for shrink technology has increased. Hot Carrier Injection (HCI) degradation for I/O transistors is most concerning part when shrink. To solve this, the effective channel length (Leff) was increased using liner oxide before Light Doped Drain (LDD) implants and optimized the tilt angle to increase Leff without E-field degradation in LDD region, satisfying the HCI specification.

• Journal of Periodontal and Implant Science
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• v.36 no.2
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• pp.345-359
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• 2006

Loss of maxillary molar teeth leads to rapid loss of crestal bone and inferior expansion of the maxillary sinus floor (secondary pneumatization). Rehabilitation of the site with osseointegrated dental implants often represents a clinical challenge because of the insufficient bone volume resulted from this phenomenon. Boyne & James proposed the classic procedure for maxillary sinus floor elevation entails preparation of a trap door including the Schneiderian membrane in the lateral sinus wall. Summers proposed another non-invasive method using a set of osteotome and the osteotome sinus floor elevation (OSFE) was proposed for implant sites with at least 5-6mm of bone between the alveolar crest and the maxillary sinus floor. The change of grafted material in maxillary sinus is important for implant survival and the evaluation of graft height after maxillary sinus floor elevation is composed of histologic evaluation and radiomorphometric evaluation. The aim of the present study was radiographically evaluate the graft height change after maxillary sinus floor elevation and the influence of the graft material type in height change and the bone remodeling of grafts in sinus. A total of 59 patients (28 in lateral approach and 31 in crestal approach) who underwent maxillary sinus floor elevation composed of lateral approach and crestal approach were radiographically followed for up to about 48 months. Change in sinusgraft height were calculated with respect to implant length (IL) and grafted sinus height(BL). It was evaluated the change of the graft height according to time, the influence of the approach technique (staged approach and simultaneous approach) in lateral approach to change of the graft height, and the influence of the type of graft materials to change of the graft height. Patients were divided into three class based on the height of the grafted sinus floor relative to the implant apex and evaluated the proportion change of that class (Class I, in which the grafted sinus floor was above the implant apex; Class II, in which the implant apex was level with the grafted sinus floor; and Class III, in which the grafted sinus floor was below the implant apex). And it was evaluated th bone remodeling in sinus during 12 months using SGRl(by $Br\ddot{a}gger$ et al). The result was like that; Sinus graft height decreased significantly in both lateral approach and crestal approach in first 12 months (p$MBCP^{TM}$ had minimum height loss. Class III and Class II was increased by time in both lateral and crestal approach and Class I was decreased by time. SGRI was increased statistically significantly from baseline to 3 months and 3 months(p<0.05) to 12 months(p$ICB^{(R)}$ single use, more reduction of sinusgraft height was appeared. Therefore we speculated that the mixture of graft materials is preferable as a reduction of graft materials. Increasing of the SGRI as time goes by explains the stability of implant, but additional histologic or computed tomographic study will be needed for accurate conclusion. From the radiographic evaluation, we come to know that placement of dental implant with sinus floor elevation is an effective procedure in atrophic maxillary reconstruction.

• Journal of Periodontal and Implant Science
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• v.36 no.3
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• pp.661-671
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• 2006

The purpose of this study was to evaluate cumulative survival rate (CSR, %) of mandibular posterior single tooth implants replaced with ITI SLA (sand-blasted, large-grit, acid-etched) implant system and compare the CSR between first and second molar. The findings from the results were as follows; 1. Total of 158 implants were inserted into 147 patients. 68 patients were males, 79 patients were females and their mean age was 47.8 years. 98 implants were placed in first molar area and 60 implants were placed in second molar area. In terms of diameter, implants with wide diameter over 4.8mm dominated (91.1%). Implants with length over lOmm were used (96.2%). 2, In the two cases, there was a slight transient numbness which recovered within 1-2 months. Nine SynOcta screw type abutments demonstrated screw loosening, There were ten cases of crown fallen-out from decementation. 3. Only one failed out of 158 implants. The CSR was 99.4%. The CSRs for first molar and second molar were 99% and 100%, respectively. From the results, it was concluded that single tooth replacement implant in the mandibular posterior area, might be considered as the effective treatment modality comparable to the conventional crown and bridge.

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.449-455
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• 2010

Implantable middle ear hearing devices(IMEHDs) have being actively studied to overcome the problems of conventional hearing aids. Vibration transducer, an output devices of IMEHDs, is attached on the ossicular chain and transmits mechanical vibration to cochlea. This approach allows us to hear more clear sound because mechanical vibration is effective to transfer high frequency acoustics, but occurs some problems such as fatigue accumulation to ossicular chian and reduction of vibration displacement caused by mass loading effect. Recently, many studies for the round window stimulation are announced, because it does not cause such problems. It have been studied by older transducers designed for attaching on ossicular chain. In this paper, we proposed a new electromagnetic transducer which consists of two magnets, three coils and a vibration membrane. The magnet assembly, magnet coupled in opposite direction, were placed in the center of three coils, and the optimum length of each coil generating maximum vibrational force was calculated by finite element analysis(FEA). The transducer was implemented as the calculated length of each coil, and measured vibration displacement. From the results, it is verified the vibration displacement can be improved by optimizing the length of coils.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.4
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• pp.326-329
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• 2002

Adequate alveolar bone height and width are required for the successful placement of dental implants. Conventional therapeutic regimens for alveolar atrophy are bone grafts or augmentation using allografts and membrane (GBR). Conventional graft techniques have some limitations and complications such as infection, soft tissue problem and high resorption rate. Recently, distraction osteogenesis of alveolar bone is considered as a new alternative for ridge augmentation. Distraction osteogenesis was originally defined and popularized by Ilizarov for lengthening of long bone. Some clinicians have tried to apply distraction osteogenesis in treatment of maxillofacial discrepancies. It was also used to augment alveolar bone. Cologne study group successfully applied the technique for augmentation of alveolar bone and designed several miniplate-distractor systems fabricated by Martin Medizintechnik GmbH in Germany. Vertical distraction of alveolar bone was successfully completed in 104 patients with miniplate-distractor systems. The mean distance of distraction was 10.2mm (range: 6-15 mm) and the mean length of segment was 45 mm (range: 6-127 mm). 162 dental implants in 54 patients were placed immediately or 4 weeks later after removal of the distractor. The results of our study show that vertical distraction of alveolar bone is an effective and reliable technique to restore alveolar atrophy and alveolar vertical defect caused by trauma or tumor.

• Journal of Dental Rehabilitation and Applied Science
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• v.21 no.2
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• pp.153-167
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• 2005

The purpose of this study was to compare the v-shape thread with the square shape thread of fixture in the view of stress distribution pattern using finite element stress analysis. The finite element model was designed with the parallel placement of two standard fixtures(4.0 mm diameter ${\times}$ 11.5 mm length) on the region of mandibular 1st and 2nd molars. Three dimensional finite element model was created with the components of the implant and surrounding bone. This study simulated loads of 200 N at the central fossa in a axial direction (load A), 200 N at the buccal offset load that is 2 mm apart from central fossa in a axial direction (load B), 200 N at the buccal offset load that was 4 mm apart from central fossa in a axial direction (load C). These forces of load A',B',C' were applied to a $15^{\circ}$ inward oblique direction at that same site with 200 N. Von Mises stress values were recorded and compared in the supporting bone, fixture, and abutment screw. The following results have been made based on this study : 1. The highest stress concentration occurred at the cervical region of the implant fixture. 2. Von Mises stress value of off-site region was higher than that of central fossa region. 3. Square shape thread type showed more even stress distribution in the vertical and oblique force than V-shape thread type. 4. Stress distribution was the most effective in the case of buccal offset load (2, 4 mm distance from central fossa) in the square shape thread type. 5. V-shape thread type revealed higher von Mises stress value than square shape thread type in all environmental condition. The results from numerical analyses concluded that square shape thread type had the lower destructive stress and more stress distribution between the fixture and bone interface than V-shape thread type. Therefore, square shape thread type was regarded as optimal thread configuration in biomechanical concepts.

• Archives of Plastic Surgery
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• v.32 no.2
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• pp.205-213
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• 2005

There are several characteristics of the nose of orientals. The dorsum of nose is flat and low, the skin is thick with severe tension, the nasal tip is bulbous, the nostril is wide, and the projection of the nose is limited due to a poorly developed alar cartilage with a short columella. In order to improve these untoward characteristics of the nose of Orientals aesthetically, plain augmentation of the dorsum and tip-plasty with conventional methods has been performed by many plastic surgeons. However these conventional rhinoplasty is not enough to obtain satisfactory results when transforming into a more beautiful and aesthetically charming appearance. In order to produce the optimal nasal shape and profile, it is extremely important to consider the aesthetic surgical factors, which are; the position of the nasion, the optimal nasolabial angle(95-100 degree in Orientals), the natural exposure of infra-tip lobule with and columella, the position of the tip defining point in harmony with the dorsal profile and the smooth and natural silhouette of the lateral nasal profile as it descends into the inferior portion of the nose. From April, 2003 to August, 2004, a total of 52 patients underwent open rhinoplasty, adhering to the strict aesthetic principles considered and described priorly. Surgical approach was done through a transcolumella incision and an alar rim incision. The nasal dorsum was augmented with a silicone implant and the shape of the columella and the nasolabial angle were finessed with a silicone strut implant which was placed in between the medial crurae in a manner of a non-visible graft. The nasal tip was corrected by alar cartilage suture technique and onlay graft of shield shaped Alloderm and Gore-Tex. Author obtained the optimal nasal shape and profile aesthetically, and the results, considered satisfactory in all patients without any complications, are as follows; 1. the average increase in nasal length was 2.5 mm, 2. the average decrease in nasal width was 2.1 mm, 3. the average increase in nasal tip projection was 3.2 mm, 4. the changes of nasolabial angles were from 85.5 degree to 94.7 degree, 5. the changes of the angle between the long axis of the external naris was from 101.3 degree to 89.5 degree. In conclusion, this surgical procedure is an effective, reliable and a valuable method in improving the nasal shape, tip projection, nasolabial angle and especially, the lateral facial profile of Orientals aesthetically.

• Journal of Periodontal and Implant Science
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• v.54 no.4
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• pp.209-223
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• 2024

Purpose: Periodontal disease is a chronic condition caused by microbial infection and mediated by the host's immune response. Phytotherapy is a therapeutic approach that utilizes a renewable resource capable of supplying less expensive medicines for the world's growing population. This review aimed to present clinical evidence on the use of complementary medicinal herbs in the treatment of periodontal diseases. Methods: Different databases were searched using the terms "herbal" and "periodontitis." All included studies were examined with a focus on herbal indications, type, and prescription length. Dentists' therapeutic and prophylactic herbal prescribing habits were also assessed. Results: Various herbs such as turmeric, neem, aloe-vera, pomegranate, catechu, tulsi, cloves, lemon grass, green tea, tea tree oil, peppermint, garlic, pineapple, oak bark, babul, bakul, sage, coriander, moringa, amla, guava, and grape seed extract have been used in the treatment of periodontitis. These herbs have been reported to exhibit a range of therapeutic effects, including anti-inflammatory, antiplaque, antihalitosis, antiresorptive, antioxidant, antibacterial, antifungal, antiviral, and antimicrobial properties. These components can be utilized in various forms such as mouth rinse, gel, oil, toothpaste, aqueous extract, mouthwash, or tooth powder. Conclusions: Several readily available herbal formulations are now available on the market and have been shown to be effective as supplemental periodontal phytotherapy. However, these should be used under the supervision of a dental professional to ensure optimal benefits and effectiveness. Therefore, it is necessary to improve the understanding of suggested herbal prescription practices among dental professionals.