• 치과방사선
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• 제29권1호
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• pp.241-254
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• 1999

The purpose of this study was to investigate whether a radiometric analysis of radicular cysts and periapical granulomas is useful in the differential diagnosis. In this experiment, twenty-nine periapical radiographs of the radicular cyst and those periapical granuloma were used. The periapical radiography was taken by intraoral paralleling device. The X-ray film was digitized and digitally filtered to reduce film-grain noise. We estimated density difference of the inner/outer area, roundness or circularity, bone profile or scan line of the margin and cumulative percentage frequency curve of radicular cyst & periapical granuloma. The obtained results were as follows; 1. The differences in density between ROIs of inner and outer area of radicular cysts were smaller than those of periapical granulomas. 2. The equivalent circular diameter was over 6.3mm, there was significant difference between periapical cyst and periapical granuloma. 3. In differential diagnosis of radicular cyst and periapical granuloma using bone profile. sensitivity. specificity and accuracy were considerably high(0.83. 0.86. 0.86) respectively. 4. Cumulative percentage frequency curve of the radicular cyst was closer to the pseudo-pixel value of 50 than average curve, whereas periapical granuloma was closer to that of 0. Hence we conclude that digital radiometric features might be useful in the differential diagnosis between radicular cyst and periapical granuloma.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권1호
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• pp.110-116
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• 2000

A 61-years old man with diabetes mellitus(DM) was admitted to our hospital, complaining of progressive right periorbital swelling, headache and toothache on the right lower second molar. On the first visit, moderate swelling was noticed from the right periorbital region with exophthalmos and subconjunctival effusion. Intraorally, right lower second molar had a severe periodontal disease and fistular formation on its distal area. From 3 days after hospitalization, the visual acuity of his right eye was gradually worsen and we performed CT scan. CT scan demonstrated an inflammatory change at the right orbit with subperiosteal abscess at the inferior orbital wall, which was extended from the right infratemporal, parapharyngeal and internal pterygoid space. Patient was treated by mean of intraoral(right upper vestibular and retromolar) and extraoral(infraorbital) incision and drainage, massive anti-therapy and DM control. The patient improved gradually and finally was discharged from the hospital, but his visual loss of right side was not recovered.

• 치과방사선
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• 제28권1호
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• pp.17-26
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• 1998

The purpose of this study was to investigate whether a radiographic estimate of osseous fractal dimension is useful in the characterization of structural changes in bone. Ten specimens of bone were progressively decalcified in fresh 50 ml solutions of 0.1 N hydrochloric acid solution at cummulative timed periods of 5, 10, 20, 30, 60 and 90 minutes, and radiographed from 0 degree projection angle controlled by intraoral parelleling device. The test set of 70 radiographs was digitized and digitally filtered to reduce film -grain noise. I performed one-dimensional variance and fractal analysis of bony profiles or scan lines. Correlation analysis quantified the relationship between variance and fractal dimension. The obtained results were as follow. 1. After the first stage of decalcification variance and fractal dimension of scan line pixel intensities generally decreased with a range of 57.94 to 12.64 and 1.59 to 1.36. 2. Correlation coefficient(r) relating variances to fractal dimensions was consistantly excellent(range r=0.90 to 0.98). 3. Variance and fractal dimension were much alike in ability to discriminate, at leat on a group basis, between control and decalcified specimens.

• 대한치과기공학회지
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• 제43권4호
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• pp.153-159
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• 2021

Purpose: The purpose of this study was to assess the fitness of anterior and posterior interim crowns fabricated by three different additive manufacturing technologies. Methods: The working model was digitized, and single crowns (maxillary right central incisor and maxillary right first molar) were designed using computer-aided design software (DentalCad 2.2; exocad). On each abutment, interim crowns (n=60) were fabricated using three types of additive manufacturing technologies. Then, the abutment appearance and internal scan data of the interim crown was obtained using an intraoral scanner. The fitness of the interim crowns were evaluated by using the superimposition of the three-dimensional scan data (Geomagic Control X; 3D Systems). The one-way analysis of variance and Tukey posterior test were used to compare the results among groups (α=0.05). Results: A significant difference was found in the fitness of the interim crowns according to the type of additive manufacturing technology (p<0.05). The posterior interim crown showed smaller root mean square value than the anterior interim crown. Conclusion: Since the fitness of the posterior interim crown produced by three types of additive manufacturing technology were all within clinically acceptable range (<120 ㎛), it can be sufficiently used for the fabrication of interim crowns.

• 대한치과보철학회지
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• 제58권4호
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• pp.282-289
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• 2020

목적:본 연구의 목표는 다른 유형의 엔도크라운(endocrown) 와동 형태를 세 가지 다른 구강스캐너로 디지털 인상을 채득하였을 때의 정확성을 평가하는 것이다. 재료 및 방법: 두 개의 인체 하악 대구치를 협측벽이 있는 것(Class 2)과 협측벽이 없는(Class 3), 두 가지 엔도크라운 지대주 디자인으로 치아형성 하였다. 와동 디자인 2종을 레퍼런스로 탁상용 스캐너(E3, 3shape)와 세 개의 다른 구강스캐너, Trios 3 (3shape, TRI group), Cerec Omnicam (Dentsply Sirona, CER group), i500 (Medit Corp., I5 group)로 스캔하였다. 표준 테셀레이션 언어(.stl) 데이터 세트를 얻어, 계측 소프트웨어에서 불러들였다. 각 구강스캐너로 획득한 반복된 스캔 데이터 사이의 편차에 기초하여 정밀도(precision)를 평가하였다. 기준 데이터와 반복하여 얻은 구강스캔 사이의 편차로서 진도(trueness)를 평가 하였다. 상호작용을 탐지하기 위해 데이터는 일변량 분산분석(ANOVA)을 사용하여 통계적으로 분석하였고, 실험군의 비교 분석을 위해 데이터는 .05의 유의 수준에서 일원 분산분석 및 사후 Tukey 테스트로 분석하였다. 결과: I5 군의 두 와동 형태에 대한 편차값은 진도의 측면에서 다른 구강스캐너 군에 비해 낮았다. 두 와동 디자인 모두에서 TRI 군은 다른 구강스캐너군 보다 우수한 정밀도를 보였다. 결론: 구강스캐너의 다양한 기술과 다양한 엔도크라운 치아형성 디자인이 디지털 스캔의 정확도에 영향을 미쳤다.

• Imaging Science in Dentistry
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• 제32권1호
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• pp.55-59
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• 2002

A 78-year-old woman was referred to Chonbuk National University Dental Hospital complaining of facial palsy and palpable mass on the right parotid gland area. Clinical examination showed non-specific findings of the intraoral region, but showed asymmetrical facial appearance. Panoramic view showed a large amorphous calcified mass on the posterior to the mandibular ramus and thin cortical plate of the posterior ramus. Sialogram showed constriction of the main duct and no further filling of striated, intercalated ducts and parenchymal areas. CT scans demonstrated an irregular, infiltrating mass with slight enhancement in the right parotid gland. The mass showed necrotic areas and calcifications. Bone scan showed marked accumulation of /sup 99m/Tc-MDP on the right posterior maxilla. Microscopic findings demonstrated the minimal morphologic alterations and rare mitotic figures within tumor cells, and diagnosed as adenocarcinoma (NOS, Grade II). This report could be aid in the diagnosis of calcified lesions of the salivary gland.

• 치과방사선
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• 제28권2호
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• pp.339-353
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• 1998

The purpose of this study was to investigate whether a radiographic estimate of osseous fractal dimension and power spectrum of 2D discrete Fourier transform is useful in the characterization of structural changes in bone. Ten specimens of bone were decalcified in fresh 50 ml solutions of 0.1 N hydrochloric acid solution at cummulative timed periods of 0 and 90 minutes. and radiographed from 0 degree projection angle controlled by intraoral parelleling device. I performed one-dimensional variance. fractal analysis of bony profiles and 2D discrete Fourier transform. The results of this study indicate that variance and fractal dimension of scan line pixel intensities decreased significantly in decalcified groups but Fourier spectral analysis didn't discriminate well between control and decalcified specimens.

• The Journal of Advanced Prosthodontics
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• 제12권5호
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• pp.299-306
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• 2020

PURPOSE. The aim of this study was to evaluate the accuracy of six recently introduced intraoral scanners (IOSs) for single crown preparations isolated from the complete arch, and to determine the effect of scanning sequence on accuracy. MATERIALS AND METHODS. A complete arch with right and left canine preparations for single crowns was used as a study model. The reference dataset was obtained by scanning the complete arch using a highly accurate industrial scanner (ATOS Core 80, GOM GmbH). Six different IOSs (Trios, iTero, Planmeca Emerald, Cerec Omnicam, Primescan, and Virtuo Vivo) were used to scan the model ten times each. The scans performed with each IOS were divided into two groups, based on whether the scanning sequence started from the right or left quadrant (n=5). The accuracy of digital impression was evaluated using three-dimensional analyzing software (Geomagic Studio 12, 3D Systems). The Kruskal Wallis and Mann- Whitney U statistical tests for trueness analysis and the One-way ANOVA test for precision analysis were performed (α=.05). RESULTS. The trueness and precision values were the lowest with the Primescan (25 and 10 ㎛), followed by Trios (40.5 and 11 ㎛), Omnicam (41.5 ㎛ and 18 ㎛), Virtuo Vivo (52 and 37 ㎛), iTero (70 and 12 ㎛) and Emerald (73.5 and 60 ㎛). Regarding trueness, iTero showed more deviation when scanning started from the right (P=.009). CONCLUSION. The accuracy of digital impressions varied depending on the IOS and scanning sequence used. Primescan had the highest accuracy, while Emerald showed the most deviation in accuracy for single crown preparations.

• 구강회복응용과학지
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• 제38권4호
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• pp.249-256
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• 2022

성공적인 상악전치부의 임플란트 식립은 많은 고려를 필요로 한다. 환자를 만족시키며 기능적이며 심미적인 보철수복을 위해서는, 치료에 앞서 정확한 진단이 선행되어야 하며 이는 구내스캔, 콘빔시티, 그리고 안면스캔을 중첩함으로 시도해 볼 수 있다. 구내스캔을 통해 얻어지는 환자의 교합양상과 콘빔시티에서 얻어지는 환자의 치조골의 양상 및 질, 그리고 안면스캔에서 얻어지는 환자의 특성과 구외평가를 어우르는 진단은 보다 성공적인 보철수복을 위한 발판이 될 수 있다. 다양한 정보의 중첩을 통해, 보철적으로 이상적인 치관의 위치를 우선순위에 두지만, 환자의 생물학적 한계를 포용하는 "탑다운"형식의 임플란트 진단은, 이를 고려한 서지컬 가이드를 3D 프린팅하고, 수술에 사용함으로써 구현되었다. 환자의 치조골 소실로 인한 임플란트 식립위치의 한계점은, 치아의 선각과 착시효과를 이용한 보철수복을 통하여 극복하려고 노력하였다. 이후, 임시수복물을 사용하고 환자가 가장 편하다고 느끼는 보철물을 장착한 뒤 디지털 교합장비(Arcus Digma II)를 이용하여 전방유도와 하악의 운동을 측정하여 이를 최종보철물에 적용하였다.

• 대한치과보철학회지
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• 제61권3호
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• pp.227-233
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• 2023

지연성 운동이상증은 도파민 수용체 차단 약물의 장기간 사용으로 인해 발생하는 비자발적 신경학적 운동 장애로 불수의적인 하악의 움직임과 이갈이를 초래하여 과도한 하중이 치아 및 보철물에 위해를 가할 수 있다. 지연성 운동이상증 병력이 있는 40대 남성이 상악 전치부 상실로 인한 보철치료를 위해 내원하였다. #13, 15, 23의 지대치 형성 후 실리콘으로 인상을 채득하고 레진 블록을 밀링하여 임시 보철물을 제작하였다. 시적 과정에서 임시 보철물의 교합면 1/3을 제거하고 교합면에 자가중합 아크릴 레진을 도포하여 환자의 구강에 장착하였다. 레진이 경화되는 동안 하악의 불수의적 움직임으로 대합치에 의한 functionally generated path (FGP)가 레진 표면에서 기록되었다. 수정된 임시 보철물을 제거하여 구내 스캐너로 스캔 후 이중 스캔 방법을 사용하여 임시 보철물의 디자인을 수정하여 최종 보철물을 설계하였다. 최종 보철물은 단일구조 지르코니아로 제작하였다. 본 증례는 FGP 기술과 이중 스캔 방법 이 지연성 운동이상증 환자에서 조화로운 교합을 갖는 고정성 보철물의 제작하는 데 도움이 될 수 있음을 보여준다.