• Imaging Science in Dentistry
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• 제31권3호
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• pp.165-173
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• 2001

Objectives : To evaluate the absorbed and effective doses of spiral and computed tomography for the dental implant planning. Materials and Methods: For radiographic projection, TLD chips were placed in 22 sites of humanoid phantom to record the exposure to skin and the mean absorbed dose to bone marrow, thyroid, pituitary, parotid and submandibular glands and nesophagus. Effective dose was calculated, using the method suggested by Frederiksen et al.. Patient situations of a single tooth gap in upper and lower midline region, edentulous maxilla and mandible were simulated for spiral tomography. 35 axial slices (maxilla) and 40 axial slices (mandible) with low and standard dose setting were used for computed tomography. All the radiographic procedures were repeated three times. Results: The mean effective dose in case of maxilla was 0.865 mSv, 0.452 mSv, 0.136 mSv and 0.025 mSv, in spiral tomography of complete edentulous maxilla, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). That in case of mandible was 0.614 mSv, 0.448 mSv, 0.137 mSv and 0.036 mSv, in spiral tomography of complete edentulous mandible, computed tomography with standard mAs, computed tomography with low mAs and spiral tomography of a single tooth gap (p<0.05). Conclusions: Based on these results, it can be concluded that low mAs computed tomography is recommended instead of spiral tomography for the complete edentulous maxilla and mandible dental implant treatment planning.

• 대한치과보철학회지
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• 제26권1호
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• pp.153-169
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• 1988

There is a little scientific documentation reporting the stress, distribution to the edentulous mandible by different concepts of occlusal scheme. So, this study was to investigate the hypothesis that the magnitude and distribution of the occlusal stresses, transmitted through a mandibular complete denture base to the edentulous mandible, would be influenced by the lingualized occlusion. This investigation was performed to analyze the stresses induced in a three-dimensional photoelastic edentulous mandible, when a load is applied to the denture arranged into lingualized occlusion in centric relation, lateral and protrusive functional position. The mounted denture on a Dentatus Type ARO articulator was loaded in a pure vertical direction with 15kgs on the center of articulator in each case and the stresses were frozen into epoxy edentulous model at $127^{\circ}C$ in the stress freezing furnace. The stress-frozen epoxy models were sliced with diamond disc saw into 4mm thick. The slices were examined with a circular polariscope. The results were as follows: 1. In centric relation, the stresses were low at anteriors, and gradually increase to the premolar, molar area and highest at the first molar and gradually decrease from the second molar and lowest at the retromolar pad region. The lingual side showed higher stresses than labiobuccal side. 2. In lateral functional position, the working side showed higher stresses than the balancing side. In working side, the lingual side showed higher stresses than the buccal side and in balancing side, the buccal side showed higher stresses than the lingual side. 3. In protrusive position, stress distribution was symmetrical on the posteriors and the stresses were concentrated at the labial side of the anteriors.

• 구강회복응용과학지
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• 제33권4호
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• pp.321-328
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• 2017

무치악은 총의치나 임플란트 보철물로 수복이 가능하며 임플란트를 이용한 피개의치는 총의치보다 유지와 안정이 우수하고, 임플란트 고정성 보철물에 비해 저렴하고 심미적이다. CM $LOC^{(R)}$ $Pekkton^{(R)}$ 어태치먼트는 여자부가 poly-ether-ketone-ketone으로 마모저항성이 뛰어나다. 한편, SR Ivocap system은 가압주사성형법으로 의치의 수직고경 변화가 적고 강도가 우수하다. 본 증례에서 상악은 4개의 임플란트 식립 후 CM $LOC^{(R)}$ $Pekkton^{(R)}$ 어태치먼트와 SR Ivocap system을 이용한 임플란트 유지 피개의치를, 하악은 가철성 국소의치를 제작하였고 심미적 및 기능적으로 만족스러운 결과를 얻었기에 이를 보고하는 바이다.

• 대한치과보철학회지
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• 제53권2호
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• pp.157-166
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• 2015

본 증례는 하악 완전 무치악 환자에서 인상채득과 석고모형 제작과정 없이 CBCT와 구강스캐너를 이용하여 수술 전에 한 번의 치과방문으로 임플란트 식립과 동시에 즉시 보철수복을 시행하는 방법을 제시하였다. 무치악 부위 연조직 형태, 수직교합고경, 상하악 악궁관계에 대한 정보는 환자가 사용하고 있는 의치를 스캔하여 얻었다. 이 방법은 무치악 환자에서 임플란트를 이용한 보철수복 과정을 기존의 방법보다 내원 횟수를 단축시켰다.

• 대한치과보철학회지
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• 제56권2호
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• pp.120-125
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• 2018

기존의 의치 인상채득 방법은 치조제 흡수가 심한 환자에게 사용하기에 한계점이 있으며, 의치상을 과도하게 연장하여 문제를 발생시킬 수 있다. 특히나 가동성조직이 존재하는 경우에는 정확한 인상 채득을 하기가 어렵고, 따라서 총의치의 적절한 안착을 방해할 수 있다. 치조제 흡수가 심한 환자에서 폐구법 인상을 이용하여 총의치를 제작하면 더 나은 안정성과 유지를 얻을 수 있다. 본 증례는 86세의 여자환자로 상악 전치부에 치은열성비대가 존재하며 하악의 심한 치조제 흡수를 보이는 무치악 환자이다. 따라서 Centric tray를 이용하여 잠정적인 교합고경을 결정 후 고딕아치 장치를 부착한 맞춤형 트레이를 제작하였고, 폐구법 인상채득을 시행하여 상하악 총의치를 제작하였으며, 의치의 충분한 안정성과 유지력을 얻어 환자의 만족도를 높였다.

• 대한치과보철학회지
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• 제54권2호
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• pp.152-159
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• 2016

상악무치악 환자에서 임플란트를 이용한 고정성 보철 수복 치료는 전통적인 가철성 의치에 비해 안정성과 유지력이 개선되어 저작, 발음 등의 기능적인 면과 환자의 심리적 안정성 및 만족도에서 이점을 갖는다. 본 증례에서 환자는 치주질환에 이환된 국소의치의 지대치를 모두 발거한 상악무치악 상태로, 7개의 임플란트를 식립하여 임플란트 지지 고정성 보철물로 수복하였다. 잔존 치조골의 흡수가 심한 전치부 골 결손부위에는 적절한 상순 지지를 얻기 위해 부피가 큰 지르코니아 하부구조물을 제작하였고, 치경부에 분홍색 도재를 축성하여 치은 연조직의 색조 및 외형을 재현하였다. 치료 후 9개월간의 임상 관찰에서 환자는 심미적, 기능적으로 만족하였고, 보철물은 합병증 없이 안정적으로 유지되었기에 이에 보고하고자 한다.

• Imaging Science in Dentistry
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• 제46권2호
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• pp.93-101
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• 2016

Purpose: The objective of this study was to investigate the effect of varying resolutions of cone-beam computed tomography images on the accuracy of linear measurements of edentulous areas in human cadaver heads. Intact cadaver heads were used to simulate a clinical situation. Materials and Methods: Fiduciary markers were placed in the edentulous areas of 4 intact embalmed cadaver heads. The heads were scanned with two different CBCT units using a large field of view ($13cm{\times}16cm$) and small field of view ($5cm{\times}8cm$) at varying voxel sizes (0.3 mm, 0.2 mm, and 0.16 mm). The ground truth was established with digital caliper measurements. The imaging measurements were then compared with caliper measurements to determine accuracy. Results: The Wilcoxon signed rank test revealed no statistically significant difference between the medians of the physical measurements obtained with calipers and the medians of the CBCT measurements. A comparison of accuracy among the different imaging protocols revealed no significant differences as determined by the Friedman test. The intraclass correlation coefficient was 0.961, indicating excellent reproducibility. Inter-observer variability was determined graphically with a Bland-Altman plot and by calculating the intraclass correlation coefficient. The Bland-Altman plot indicated very good reproducibility for smaller measurements but larger discrepancies with larger measurements. Conclusion: The CBCT-based linear measurements in the edentulous sites using different voxel sizes and FOVs are accurate compared with the direct caliper measurements of these sites. Higher resolution CBCT images with smaller voxel size did not result in greater accuracy of the linear measurements.

• 구강회복응용과학지
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• 제31권3호
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• pp.242-252
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• 2015

무치악 환자에서는 치아가 상실되면서 주위 치조골의 개조와 흡수가 일어나고, 이에 따라 총의치의 유지력 감소, 저작 효율의 저하와 통증으로 인해 의치 사용에 어려움을 겪게 된다. 이를 개선하기 위해 하악에 2 - 4개의 임플란트를 식립하고 어태치먼트에서 유지 또는 지지를 얻는 피개의치가 바람직한 치료 방법으로 고려되고 있다. 본 증례들은 하악 완전 무치악 환자들을 악간 관계, 골흡수 정도, 안모지지 등을 평가하여 하악에 2개의 임플란트 식립을 고려하고, 다양한 종류의 어태치먼트를 이용한 임플란트 피개의치 수복을 계획하여 치료하였다. 주기적인 경과 관찰 결과 심미적, 기능적으로 만족할만한 결과를 얻었기에 이를 보고하는 바이다.

• The Journal of Advanced Prosthodontics
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• 제5권1호
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• pp.58-66
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• 2013

PURPOSE. The purpose of this study was to decide the most appropriate point on tragus to be used as a reference point at time of marking ala tragus line while establishing occlusal plane. MATERIALS AND METHODS. The data was collected in two groups of subjects: 1) Dentulous 2) Edentulous group having sample size of 30 for each group with equal gender distribution (15 males, 15 females each). Downs analysis was used for base value. Lateral cephalographs were taken for all selected subjects. Three points were marked on tragus as Superior (S), Middle (M), and Inferior (I) and were joined with ala (A) of the nose to form ala-tragus lines. The angle formed by each line (SA plane, MA plane, IA plane) with Frankfort Horizontal (FH) plane was measured by using custom made device and modified protractor in all dentulous and edentulous subjects. Also, in dentulous subjects angle between Frankfort Horizontal plane and natural occlusal plane was measured. The measurements obtained were subjected to the following statistical tests; descriptive analysis, Student's unpaired t-test and Pearson's correlation coefficient. RESULTS. The results demonstrated, the mean angle COO (cant of occlusal plane) as $9.76^{\circ}$, inferior point on tragus had given the mean angular value of IFH [Angle between IA plane (plane formed by joining inferior point-I on tragus and ala of nose- A) and FH plane) as $10.40^{\circ}$ and $10.56^{\circ}$ in dentulous and edentulous subjects respectively which was the closest value to the angle COO and was comparable with the values of angle COO value in Downs analysis. Angulations of ala-tragus line marked from inferior point with occlusal plane in dentulous subject had given the smallest value $2.46^{\circ}$ which showed that this ala-tragus line was nearly parallel to occlusal plane. CONCLUSION. The inferior point marked on tragus is the most appropriate point for marking ala-tragus line.

• 구강회복응용과학지
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• 제16권3호
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• pp.187-196
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• 2000

This study was performed to offer convenience to determine the vertical dimension of occlusion of edentulous patients by investigating the interocclusal distances at physiologic rest position, at speaking of /m/ sound, and some korean short sounds, that is, /mem/ and /beb/ sounds, which were found in our previous study with dentulous subjects. Ten edentulous subjects - 6 men and 4 women - were selected for this study. The frequencies at speaking of /m/, /mem/, and /beb/ sounds were analyzed with Computerized speech lab($CSL^{TM}$, Model 4300B, Software version 5.X, Kay Elemetrics Co. U.S.A.). And the interocclusal distances at physiologic rest position and at speaking of /m/, /mem/, and /beb/ sounds were measured with K6 diagnostic system(Myo-tronics, Inc. U.S.A.). The results of this study were as follows ; 1. In the acoustic analysis by Computerized speech lab, frequencies of sounds of edentulous subjects with complete denture at speaking of /m/, /mem/, and /beb/ were similar to those of dentulous subjects. 2. In the linear correlation by Pearson's correlation coefficient, the interocclusal distance at physiologic rest position was most similar to those of speaking /mem/ sound, secondly /m/ sound, and thirdly /beb/ sound(p<0.05). In reliability by Cronbach's alpha, the results were reliable with alpha value 0.97. 3. It was found by Levene's test for equality of variance that the difference between men and women in the interocclusal distances at physiologic rest position and at speaking of /m/, /mem/, and /beb/ sounds was not statistically significant(p>0.05).