• 한국치위생학회지
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• 제17권2호
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• pp.235-245
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• 2017

Objectives: The purpose of this study was to investigate how wisdom tooth extraction is perceived, and to correct erroneous perceptions thereby establishing proper awareness. Methods: We conducted a survey on how wisdom tooth extraction was perceived among adults in 20 households in Seoul and Gyeonggi province starting in December, 2016. Results: A review of the factors influencing the perception of wisdom tooth extraction showed that the regression model was statistically significant and the model had an explanatory power of 8.3%. It was also found that those in their 20s or younger had saw a lower level of perceived oral health, and a higher level in perception in wisdom tooth extraction. Moreover, students, housewives, and professions showed a lower perception of wisdom tooth extraction. Conclusions: It is necessary to have an education program for adults aged 60 or older who have few opportunities for oral health education.

• 대한치과기공학회지
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• 제42권2호
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• pp.99-105
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• 2020

Purpose: A study analysed the stress distribution of abutment screw and supporting bone of fixture by the tightening torque force of the abutment screw within clinical treatment situation for the stability of the dental implant prosthesis. Methods: The finite element analysis was targeted to the mandibular molar crown model, and the implant was internal type 4.0 mm diameter, 10.0 mm length fixture and abutment screw and supporting bone. The occlusal surface was modeled in 4 cusps and loaded 100 N to the buccal cusps. The connection between the abutment and the fixture was achieved by combining three abutment tightening torque forces of 20, 25, and 30 Ncm. Results: The results showed that the maximum stress value of the supporting bone was found in the buccal cortical bone region of the fixture in all models. The von Mises stress value of each model showed 184.5 MPa at the 20 Ncm model, 195.3 MPa in the 25 Ncm model, and 216.5 MPa in the 30 Ncm model. The contact stress between the abutment and the abutment screw showed the stress value in the 20 Ncm model was 201.2 MPa, and the 245.5 MPa in the 25 Ncm model and 314.0 MPa in the 30 Ncm model. Conclusion: The increase of tightening force within the clinical range of the abutment screw of the implant dental prosthesis was found to have no problem with the stability of the supporting bone and the abutment screw.

• 한국치위생학회지
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• 제19권6호
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• pp.1067-1075
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• 2019

Objectives: The present study aimed to compare the accuracy of removable partial denture (RPD) frameworks fabricated by selective laser sintering (SLS) before and after electropolishing. Methods: A partially edentulous mandibular model was used as the working model. Scanning of the model was performed using a dental scanner. The framework was designed using CAD software. The metal framework was formed using an SLS 3D printer. 3D scans of the two fabricated prototypes produced before and after electropolishing were overlapped with reference data. The fit was calculated based on Root Mean Square (RMS). Fabrication accuracy was verified using the paired t-test to compare the discrepancy before and after electropolishing. Results: The mean (SD) values of RMS before and after electropolishing were 126.6 (34.19) and 75.86 (21.36), respectively. There was a statistically significant difference before and after electropolishing (p<0.05). Conclusions: Metal frameworks made with SLS 3D printers showed clinically acceptable fit after electropolishing.

• 대한구순구개열학회지
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• 제14권1_2호
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• pp.45-56
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• 2011

Face transplantation has been reported over the last six years, and it started in 2004 with the announcement of Cleveland Clinic granting the world's first IRB approval to proceed with human face transplantation. Composite tissue allografts (CTAs) in the facial region are considered to be more immunogenic than other solid organ transplants, so these kinds of animal experiments were also considered as challengeable activities to the facial reconstructive surgeons. For the better understanding of CTAs in the oral and maxillofacial fields, we reviewed several recent articles about facial composite transplantation animal model, and summarized some knowledges of composite midface allotransplantation model with sensory and motor reinnervation in this review article.

• 치위생과학회지
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• 제15권2호
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• pp.226-231
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• 2015

본 연구는 세 가지 종류 스캐너에 따른 정확도를 비교 평가하기 위하여 시행되었다. 경석고 모형과 스캐너로 채득한 디지털 모형에 각 4지점씩 계측지점을 선정하였고, 이들 4지점사이를 DVC와 디지털 모형 측정 프로그램을 이용하여 길이를 측정하고, 다음과 같은 결론을 도출하였다. 세 가지 종류의 스캐너 가운데 레이저 스캐너가 백색광 스캐너나 청색광 스캐너보다 높은 정확도를 나타내었으나 이 세 가지 종류의 스캐너 모두가 임상적으로 사용하는 것이 가능하다.

• 치위생과학회지
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• 제19권1호
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• pp.48-59
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• 2019

Background: The purpose of this study is to provide the data for discussions related to oral health promotion policies for single-person households by analyzing the status of unmet dental needs and related factors in single-person households in Korea, based on the Anderson model. Methods: The data, obtained from 544 single-person households of those over 20 years old who were targeted for the 6th Korea National Health and Nutrition Examination Survey, were analyzed through a complex sample frequency analysis, complex sample cross analysis (Rao-Scott chi-square test), and complex sample binary logistic regression analysis on a complex sampling design. Results: The most frequently given reason for an unmet dental need among single-person households was economic (52.4%). Factors related to the unmet dental needs of single-person households are smoking, which is a predisposing factor; personal income levels, which are an enabling factor; chewing discomfort; and limited daily activities, which are need factors. Smokers, the high-income group, the chewing-discomfort group, and the limited activity group showed high unmet dental care experience. Smokers had a 2.75 times higher rate of unmet dental care than non-smokers, and the high-income group had a 5.29 times higher rate of unmet dental needs than the median group. The rate of unmet dental needs for the chewing discomfort group was 3.27 times higher than the non-chewing discomfort group, and the limited activity group had a 7.87 times higher rate of unmet dental needs than the non-limited activity group. Conclusion: It is necessary to map out policies designed to help maintain and promote met dental needs considered to be internally heterogeneous to single-person householders, based on the Anderson model.

• 치위생과학회지
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• 제12권6호
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• pp.617-623
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• 2012

본 연구는 치과용 모형재 중 4형(type IV)석고와 스캔용(scannable)석고를 이용하여 작업모형을 제작한 후, 치과용 백색광 스캐너를 이용하여 3차원 디지털 모형으로 전환한 데이터의 계측지점간 거리를 측정하여, 그 결과 값을 토대로 이종의 치과용 석고가 3차원 디지털 모형의 크기재현 시 정확성여부를 비교하였다. 본 실험을 통하여 치과용 모형재에 따른 3차원 디지털 모형의 정확도를 확인함으로써 임상 적용의 가능성을 평가하였으며, 제한된 조건 하에서 수행된 본 연구에서 다음과 같은 결론을 얻었다. 1. 치과용 백색광 스캐너를 사용하여 주 모형과 두 종류의 모형재로 제작한 작업모형을 3차원 디지털 모형으로 전환한 후, 선계측의 값을 비교한 결과 전체적인 계측지점에서 모두 모형재로 제작된 작업모형이 작게 계측되는 경향을 보였다. 2. 각 모형별 동일한 계측지점의 계측값의 차이가 있는지 알아보기 위해 paired t-test의 시행결과, 모든 계측지점에서 통계적으로 유의한 차이를 보였다(p<0.05). 결론적으로 두 가지 석고 모두 통계적으로 적정한 수준의 정확성을 나타내지 않았으나, 오차 수준이 선행연구에 비추어 볼 때 임상적으로 수용 가능한 수준이라 생각된다. 전악 인상채득을 통한 디지털 모형의 정확성은 검증이 되었으나, 스캔용(scannable)석고에 대한 임상 효용성을 판단하기 위해 타 제품과의 성분 분석 비교연구나 실질적인 보철물 제작을 통한 적합도 평가를 통해 CAD/CAM 보철물 제작 시장점을 부각할 수 있는 연구가 뒷받침되어야 할 것으로 사료된다.

• 대한치과기공학회지
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• 제34권3호
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• pp.213-220
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• 2012

Purpose: The aim of this study was to determine the repeatability and reproducibility of two dental scanners. Methods: The master die and the stone replicas(Kavo, Germany) were digitized in touch-probe scanner(Incise, Renishaw, UK), white light scanner(Identica, Medit, Korea) to create 3-dimensional surface-models. The number of points in the point clouds from each reading were calculated and used as the CAD reference model(CRM). Discrepancies between the points in the 3-dimensional surface models and the corresponding CRM were measured by a matching-software(Power-Inspect R2, Delcam Plc, UK). The t-student test for one samples were used for statistical analysis. Results: The reproducibility of both scanner was within $3{\mu}m$, based on mean value. The mean value between measurements made directly on the touch probe scanner digital models and those made on the white light scanner digital models was $2.20-2.90{\mu}m$, and was statistically significant(P<0.05). Conclusion: With respect to adequate data acquisition, the reproducibility of dental scanner differs. Three-dimensional analysis can be applied to differential quality analysis of the manufacturing process as well as to evaluation of different analysis methods.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제42권1호
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• pp.20-30
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• 2016

Objectives: To validate a critical-size mandibular bone defect model in miniature pigs. Materials and Methods: Bilateral notch defects were produced in the mandible of dentally mature miniature pigs. The right mandibular defect remained untreated while the left defect received an autograft. Bone healing was evaluated by computed tomography (CT) at 4 and 16 weeks, and by micro-CT and non-decalcified histology at 16 weeks. Results: In both the untreated and autograft treated groups, mineralized tissue volume was reduced significantly at 4 weeks post-surgery, but was comparable to the pre-surgery levels after 16 weeks. After 16 weeks, CT analysis indicated that significantly greater bone was regenerated in the autograft treated defect than in the untreated defect (P=0.013). Regardless of the treatment, the cortical bone was superior to the defect remodeled over 16 weeks to compensate for the notch defect. Conclusion: The presence of considerable bone healing in both treated and untreated groups suggests that this model is inadequate as a critical-size defect. Despite healing and adaptation, the original bone geometry and quality of the pre-injured mandible was not obtained. On the other hand, this model is justified for evaluating accelerated healing and mitigating the bone remodeling response, which are both important considerations for dental implant restorations.

• 드라이브 ㆍ 컨트롤
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• 제20권1호
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• pp.27-33
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• 2023

From the perspective of dental chair manufacturers, it is important to of localizing hydraulic system in order to secure market competitiveness. This study aims to develop the analysis model of a dental chair which overseas companies secure core technologies. The study follows the steps below. First, the component parts of the solenoid valve unit of a foreign leading company are analyzed and implemented in virtual environment. Second, dynamic behavior scenario is established based on solenoid valve signal chart provided by a foreign leading company. The analysis model is verified and its performance is analyzed using dynamic behavior according to each scenario. Third, a simulation is carried out to determine whether the cylinder velocity of designed hydraulic system surpasses 1cm/s as required by the design.