• Imaging Science in Dentistry
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• v.37 no.3
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• pp.171-180
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• 2007

The role of radiographic imaging in determining the size, numbers and the position of implants is very important. To perform the implant procedure, the dentist needs to evaluate the bone pathology and bone density, and to know the precise height, width, and contour of the alveolar process, as well as its relationship to the maxillary sinus and mandibular canal. The author analyzed 3 implant cases for treatment planning with the cone beam CT. All axial, panoramic, serial and buccolingual-sectioned images of 3 cases with stent including vertical marker were taken by using Mercuray (Hitachi, Japan). When the curved line drawn intentionally did not include dot image of a vertical marker on the axial image of CBCT, the image of the vertical marker was deformed on its buccolingually sectioned image. There was wide discrepancy in inclination between the alveolar bone and tooth on buccolingually sectioned image.

• Proceedings of the KOSOMBE Conference
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• v.1998 no.11
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• pp.163-164
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• 1998

In this paper the digital speech processing part of cochlear implant for sensorineural disorderly patients is implemented and simulated. We implement the speech processing part by dividing into three small parts - Filterbank, Pitch Detect, and Bandmapping parts. With the result, we conclude digital speech processing algorithm is implemented in FPGA perfectly. This means that cochlear implant can be made very small size.

• Journal of Korean Dental Science
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• v.15 no.1
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• pp.84-91
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• 2022

An all-on-4 restoration allows edentulous patients to use a fixed prosthesis with a minimum number of implants. These implant-supported fixed complete dentures have traditionally been fabricated as screw-retained or cement-retained prostheses. However, it is difficult to passively fit the long-span full-arch prosthesis using the screw-retained type restoration, and predictable retrievability is not obtained with the cement-retained type. This case report describes a prosthesis fabricated using a combination of the two retention types. The screwmentable method allows the implant-supported fixed complete denture to achieve a passive fit at the connection with retrievability. In addition, a framework with an optimized size was designed by using digital dental technology.

• Journal of Audiology & Otology
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• v.24 no.1
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• pp.17-23
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• 2020

Background and Objectives: We aimed to measure the head dimensions on computed tomography (CT) images, to compare them to directly measured head dimensions, and to predict a new parameter of bone thickness for aiding bone conduction implant (BCI) placement. Subjects and Methods: We reviewed the facial and mandibular bone CT images of 406 patients. Their head sizes were analyzed using five parameters included in the 6th Size Korea project, and they were divided into age groups (ranging from the 10s to the 80s). We compared the head length, head width, sagittal arc, bitragion arc, and head circumference in the CT and Size Korea groups. We also added the parameter bone thickness for aiding BCI placement. Results: All the head size parameters measured using CT were significantly smaller than those measured directly, with head length showing the smallest difference at 7.85 mm. The differences in the other four parameters between the two groups according to patient age were not statistically significantly different. Bone thickness had the highest value of 4.89±0.93 mm in the 70s and the lowest value of 4.10±0.99 mm in the 10s. Bone thickness also significantly correlated with head width (p=0.038). Conclusions: Our findings suggested that the CT and direct measurements yielded consistent data. Moreover, CT enabled the measurement of bone sizes, including bone thickness, that are impossible to measure directly. CT measurements may complement direct measurements in the Size Korea data when used for developing bone conduction hearing devices (BCIs and headsets) for the Korean population.

• Korean Journal of Audiology
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• v.24 no.1
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• pp.17-23
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• 2020

Background and Objectives: We aimed to measure the head dimensions on computed tomography (CT) images, to compare them to directly measured head dimensions, and to predict a new parameter of bone thickness for aiding bone conduction implant (BCI) placement. Subjects and Methods: We reviewed the facial and mandibular bone CT images of 406 patients. Their head sizes were analyzed using five parameters included in the 6th Size Korea project, and they were divided into age groups (ranging from the 10s to the 80s). We compared the head length, head width, sagittal arc, bitragion arc, and head circumference in the CT and Size Korea groups. We also added the parameter bone thickness for aiding BCI placement. Results: All the head size parameters measured using CT were significantly smaller than those measured directly, with head length showing the smallest difference at 7.85 mm. The differences in the other four parameters between the two groups according to patient age were not statistically significantly different. Bone thickness had the highest value of 4.89±0.93 mm in the 70s and the lowest value of 4.10±0.99 mm in the 10s. Bone thickness also significantly correlated with head width (p=0.038). Conclusions: Our findings suggested that the CT and direct measurements yielded consistent data. Moreover, CT enabled the measurement of bone sizes, including bone thickness, that are impossible to measure directly. CT measurements may complement direct measurements in the Size Korea data when used for developing bone conduction hearing devices (BCIs and headsets) for the Korean population.

• Journal of Periodontal and Implant Science
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• v.43 no.4
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• pp.153-159
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• 2013

Purpose: The level of the implant above the marginal bone and flap design have an effect on the bone resorption during the healing period. The aim of this study is to detect the relationship between the level of the implant at the implant placement and the bone level at the healing period in the mesial and distal side of implants placed with flapless (FL) and full-thickness flap (FT) methods. Methods: Twenty-two nonsubmerged implants were placed with the FL and FT technique. Periapical radiographs were taken of the patient at implant placement, and at 6 and 12 weeks. By using computer software, bone level measurements were taken from the shoulder of the healing cap to the first bone implant contact in the mesial and distal side of the implant surface. Results: At 6 weeks, the correlation between the crestal bone level at the implant placement and crestal bone level of the FT mesially was significant (Pearson correlation coefficient=0.675, P<0.023). At 12 weeks, in the FT mesially, the correlation was nonsignificant (Spearman correlation coefficient=0.297, P<0.346). At 6 weeks in the FT distally, the correlation was nonsignificant (Pearson correlation coefficient=0.512, P<0.107). At 12 weeks in the FT distally, the correlation was significant (Spearman correlation coefficient=0.730, P<0.011). At 6 weeks in the FL mesially, the correlation was nonsignificant (Spearman correlation coefficient=0.083, P<0.809). At 12 weeks in the FL mesially, the correlation was nonsignificant (Spearman correlation coefficient= 0.062, P<0.856). At 6 weeks in the FL distally, the correlation was nonsignificant (Spearman correlation coefficient=0.197, P<0.562). At 12 weeks in the FL distally, the correlation was significant (Pearson correlation coefficient=0.692, P<0.018). Conclusions: A larger sample size is recommended to verify the conclusions in this preliminary study. The bone level during the healing period in the FT was more positively correlated with the implant level at implant placement than in the FL.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.12
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• pp.1150-1158
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• 2013

Artificial cochlear implant system is known as the most efficient and widespread device to patients who have cochlear disorder. However, current commercialized artificial cochleas have inconveniences because of large volume size and high power consumption, requiring further research on improvements in terms of the size, power, and performance. In this paper, we will introduce our fully implantable artificial cochlear implant system, where small-size sensors and actuators are wirelessly connected, focusing on communication system design and its performance simulation.

• Korean Journal of Computational Design and Engineering
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• v.13 no.3
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• pp.200-208
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• 2008

Total Hip Replacement(THR) is a surgical procedure that replaces a diseased hip joint with a prosthesis. A plastic or metal cup forms the socket, and the head of the femur is replaced by a metal ball on a stem placed inside the femur. Due to the various types and shapes of human hip joint of every individual, a selected commercial implant sometimes may not be the best-fit to a patient, or it cannot be applied because of its discrepancy. Hence extracting geometry parameters of hip joint is one of the most crucial processes in designing custom-made implants. This paper describes the framework of a methodology to extract the geometric parameters of the hip joint. The parameters include anatomical axis, femoral head, head offset length, femoral neck, neck shaft angle, anteversion, acetabulum, and canal flare index. The proposed system automatically recommends the size and shape of a custom-made hip implant with respect to the patient's individual anatomy from 3D models of hip structures. The proposed procedure creating these custom-made implants with some typical examples is precisely presented and discussed in this paper.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.643-651
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• 2013

This study applied a laser cleaning method (dry cleaning) that is used for cleaning semiconductor elements to dental implant cleaning. The lasers used in this study were pulsed fiber lasers with wavelengths of 1,064 and 532 nm. The peak output, energy per pulse, energy density per pulse, time of pulse experiment, and number of pulse experiments served as process variables for this study, and the variables were changed for each experiment. As a result, a laser with a wavelength of 532 nm showed much higher cleaning efficiency than its 1,064 nm counterpart. As the wavelength range decreased, the quantized energy increased and the reflection rate of the titanium used for the implant decreased; consequently, the energy absorption rate increased. Therefore, it is proposed that the energy density by wavelength has a greater influence on cleaning than does the output size.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.144-151
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• 2003

In this paper, an optimum design problem for endosseous implant in dentistry is studied to find best implant design. An optimum design problem is formulated to reduce stresses arising at the cortical as well as cancellous bones, in which sufficient design parameters are chosen fur design definition that encompasses major implants in popular use. Optimization at once (OAO) with the large number of design variables, however, causes too costly solution or even failure to converge. A concept of multilevel optimization (MLO) is employed to this end, which is to group the design variables of similar nature, solve the sub-problem of smaller size fur each group in sequence, and this is iterated until convergence. Each sub-problem is solved based on the response surface method (RSM) due to its efficiency for small sized problem. Favorable solution is obtained by the MLO, which is compared to both solutions made by RSM and sequential quadratic programming (SQP) in the OAO problem.