• 대한치과의사협회지
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• 제50권3호
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• pp.140-147
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• 2012

Recently, the digital solution of fabricating removable prosthesis by applying haptic input device, electronic surveying, and rapid prototyping was introduced. This review article covers the concept of electronic surveying, computer-aided denture framework designing procedure, discussions after several digital denture cases, directions of future development, such as digital tooth arrangement and RP flasking.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권5호
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• pp.555-561
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• 2008

Purpose: The goal of this study was to develop a technique for creating a computerized composite maxillofacial-dental model, based on point-based surface best fit algorithm and to test its accuracy. The computerized composite maxillofacial-dental model was made by the three dimensional combination of a 3-dimensional (3D) computed tomography (CT) bone model with digital dental model. Materials and Methods: This integration procedure mainly consists of following steps : 1) a reconstruction of a virtual skull and digital dental model from CT and laser scanned dental model ; 2) an incorporation of dental model into virtual maxillofacial-dental model by point-based surface best fit algorithm; 3) an assessment of the accuracy of incorporation. To test this system, CTs and dental models from 3 volunteers with cranio-maxillofacial deformities were obtained. And the registration accuracy was determined by the root mean squared distance between the corresponding reference points in a set of 2 images. Results and Conclusions: Fusion error for the maxillofacial 3D CT model with the digital dental model ranged between 0.1 and 0.3 mm with mean of 0.2 mm. The range of errors were similar to those reported elsewhere with the fiducial markers. So this study confirmed the feasibility and accuracy of combining digital dental model and 3D CT maxillofacial model. And this technique seemed to be easier for us that its clinical applicability can good in the field of digital cranio-maxillofacial surgery.

• Restorative Dentistry and Endodontics
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• 제23권2호
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• pp.575-585
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• 1998

Use of the digital camera as a color measuring device was proposed. Digital camera can save, adjust and transmit image using computer. But it has great disadvantage that color of image possibly altered by environment of image capturing state, so the color reproducibility of digital camera can severly damage, Casmatch, the supplement for color correction, was proposed for enhance the color reproducibility of digital camera. Thus for study the efficacy of the Casmatch in enhancing the color reproducibility of digital camera, image of 78area in 39teeth was captured three times during two days and color reproducibility was evaluated and analyzed in terms of the use of Casmatch, teeth positions, and area within the tooth and comparatively analyzed. Results were as follow ; 1. ${\Delta}$E the color reproducibility of digital camera was 6.90${\pm}$3.27 in same day and 7.43${\pm}$3.94 in different day, and the color reproducibility when using Casmatch correction was 6.21${\pm}$3.86, 7.59${\pm}$4.48, there is no enhancement in using Casmatch correction. 2. There is no difference in color reproducibility between teeth, but color reproducibility of the middle third was greater(p<0.05) than the gingival third before color correction using Casmatch.

• 대한치과보철학회지
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• 제60권1호
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• pp.80-90
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• 2022

디지털 치의학이 발전함에 따라 치과 치료 방식도 다양하게 변화하고 있다. 본 증례에서는 구치부의 병적인 마모로 수직 고경 소실을 보이는 환자에서 적절한 수직 고경을 설정한 후, 디지털 기술을 이용하여 최종 보철물을 사전에 디자인하였다. 이를 바탕으로 치질을 최대로 보존할 수 있도록 치아 삭제량을 계산하였으며, 구내에서 치아 삭제량을 나타내줄 수 있는 가이드를 디자인하였다. 본 가이드를 이용함으로써 복잡한 다수 치아의 삭제가 편리했으며 보다 정확하고 빠른 치아 형성이 가능하였다. 이후 이중 스캔으로 임시 보철물의 정보를 반영하여 전악 지르코니아 크라운으로 최종 보철물을 제작하였다. 디지털 기술을 이용하여 전악 수복 증례의 술 전 계획부터 최종 보철물 장착까지의 복잡한 과정을 빠르고 간편하게 해결할 수 있어, 환자와 술자가 모두 만족할 수 있었다.

• Imaging Science in Dentistry
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• 제43권3호
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• pp.145-151
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• 2013

Purpose: This study was performed to evaluate and compare the radiopacity of dentin, enamel, and 8 restorative composites on conventional radiograph and digital images with different resolutions. Materials and Methods: Specimens were fabricated from 8 materials and human molars were longitudinally sectioned 1.0 mm thick to include both enamel and dentin. The specimens and tooth sections were imaged by conventional radiograph using #4 sized intraoral film and digital images were taken in high speed and high resolution modes using a phosphor storage plate. Densitometric evaluation of the enamel, dentin, restorative materials, a lead sheet, and an aluminum step wedge was performed on the radiographic images. For the evaluation, the Al equivalent (mm) for each material was calculated. The data were analyzed using one-way ANOVA and Tukey's test (p<0.05), considering the material factor and then the radiographic method factor, individually. Results: The high speed mode allowed the highest radiopacity, while the high resolution mode generated the lowest values. Furthermore, the high resolution mode was the most efficient method for radiographic differentiation between restorative composites and dentin. The conventional radiograph was the most effective in enabling differentiation between enamel and composites. The high speed mode was the least effective in enabling radiographic differentiation between the dental tissues and restorative composites. Conclusion: The high speed mode of digital imaging was not effective for differentiation between enamel and composites. This made it less effective than the high resolution mode and conventional radiographs. All of the composites evaluated showed radiopacity values that fit the ISO 4049 recommendations.

• Imaging Science in Dentistry
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• 제51권3호
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• pp.279-290
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• 2021

Purpose: Using images in the facial image comparison process poses a challenge for forensic experts due to limitations such as the presence of facial expressions. The aims of this study were to analyze how morphometric changes in the face during a spontaneous smile influence the facial image comparison process and to evaluate the reproducibility of measurements obtained by digital stereophotogrammetry in these situations. Materials and Methods: Three examiners used digital stereophotogrammetry to obtain 3-dimensional images of the faces of 10 female participants(aged between 23 and 45 years). Photographs of the participants' faces were captured with their faces at rest (group 1) and with a spontaneous smile (group 2), resulting in a total of 60 3-dimensional images. The digital stereophotogrammetry device obtained the images with a 3.5-ms capture time, which prevented undesirable movements of the participants. Linear measurements between facial landmarks were made, in units of millimeters, and the data were subjected to multivariate and univariate statistical analyses using Pirouette^® version 4.5 (InfoMetrix Inc., Woodinville, WA, USA) and Microsoft Excel^® (Microsoft Corp., Redmond, WA, USA), respectively. Results: The measurements that most strongly influenced the separation of the groups were related to the labial/buccal region. In general, the data showed low standard deviations, which differed by less than 10% from the measured mean values, demonstrating that the digital stereophotogrammetry technique was reproducible. Conclusion: The impact of spontaneous smiles on the facial image comparison process should be considered, and digital stereophotogrammetry provided good reproducibility.

• 대한치과의사협회지
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• 제54권2호
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• pp.134-141
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• 2016

Use of ready-made orthodontic appliance can lead to inefficiencies in the final stages of the orthodontic treatment. Because patients' teeth have anatomic variations, brackets that have been designed to fit on average tooth surface may result in positional discrepancies when leveling and alignment is completed. As a result, additional steps such as rebonding, wire bending and use of auxiliaries may be needed. Even in patients who have normal tooth anatomy and proper tooth size relationships, precise bracket placement is crucial in order to efficiently control the tooth positions. Digital models can provide advantages in clinical orthodontics as virtual tooth setup could be performed, and clinicians can easily visualize the predicted final occlusion. Through this setup model, customized brackets with individualized prescription and archwires that optimally fit with the patients' dental arches can be produced using CAD/CAM technology. Also, the brackets can be accurately placed with an aid of 3D-printed jigs. The purpose of this article is to introduce the commonly used labial and lingual customized orthodontic appliance systems using digital technology.

• 대한치과교정학회지
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• 제45권2호
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• pp.82-88
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• 2015

Objective: The aim of this study was to evaluate the reliability of measurements obtained after the superimposition of three-dimensional (3D) digital models by comparing them with those obtained from lateral cephalometric radiographs and photocopies of plaster models for the evaluation of upper molar distalization. Methods: Data were collected from plaster models and lateral cephalometric radiographs of 20 Class II patients whose maxillary first molars were distalized with an intraoral distalizer. The posterior movements of the maxillary first molars were evaluated using lateral cephalometric radiographs (group CP), photocopies of plaster models (group PH), and digitized 3D models (group TD). Additionally, distalization and expansion of the other teeth and the degrees of molar rotation were measured in group PH and group TD and compared between the two groups. Results: No significant difference was observed regarding the amount of molar distalization among the three groups. A comparison of the aforementioned parameters between group PH and group TD did not reveal any significant difference. Conclusions: 3D digital models are reliable to assess the results of upper molar distalization and can be considered a valid alternative to conventional measurement methods.

• 대한치과의사협회지
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• 제57권9호
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• pp.529-533
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• 2019

Recently, an advanced workflow has been introduced to finish implant surgery and prosthetic treatment in one-day. However, Because of 1. Patient's physical condition, 2. Surgical technique, 3. Digital technical limitations, the complete completion of one-day implant treatment is practically difficult. Therefore, this paper proposes a "two-days implant digital workflow" that short-time implant surgery and restores prosthetics the next day. Even though it takes more than one day, this workflow is a realistic implant treatment protocol that can reduce the chair time in the clinic.

• 대한치과교정학회지
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• 제53권2호
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• pp.77-88
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• 2023

Objective: To develop a method for generating three-dimensional (3D) digital models of the periodontal ligament (PDL) using 3D cone-beam computed tomography (CBCT) reconstruction and to evaluate the accuracy and agreement of the 3D PDL models in the measurement of periodontal bone loss. Methods: CBCT data collected from four patients with skeletal Class III malocclusion prior to periodontal surgery were reconstructed at three voxel sizes (0.2 mm, 0.25 mm, and 0.3 mm), and 3D tooth and alveolar bone models were generated to obtain digital PDL models for the maxillary and mandibular anterior teeth. Linear measurements of the alveolar bone crest obtained during periodontal surgery were compared with the digital measurements for assessment of the accuracy of the digital models. The agreement and reliability of the digital PDL models were analyzed using intra- and interexaminer correlation coefficients and Bland-Altman plots. Results: Digital models of the maxillary and mandibular anterior teeth, PDL, and alveolar bone of the four patients were successfully established. Relative to the intraoperative measurements, linear measurements obtained from the 3D digital models were accurate, and there were no significant differences among different voxel sizes at different sites. High diagnostic coincidence rates were found for the maxillary anterior teeth. The digital models showed high intra- and interexaminer agreement. Conclusions: Digital PDL models generated by 3D CBCT reconstruction can provide accurate and useful information regarding the alveolar crest morphology and facilitate reproducible measurements. This could assist clinicians in the evaluation of periodontal prognosis and establishment of an appropriate orthodontic treatment plan.