• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.465-473
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• 1999

Bond strength of luting cements to dentin is a critical consideration for success of complete cast crowns. This study was performed to evaluate the relationship between surface characteristics of teeth prepared for complete cast crowns and retention of cemented restorations. Eighty artificial crowns were cast for standardized complete crown tooth preparations accomplished with the use of a special device on recently extracted human teeth. Coarse diamond(#102R, Shofu) and superfine finishing diamond(#SF102R, Shofu) burs of similar shape were used. Crowns in each group were randomly subdivided into few subgroups of 10 for luting cements selected for this study: zinc phosphate cement (FLECK' S), polycarboxylate cement (Poly-F), rein-forced glass ionomer cement (Fuji PLUS). and adhesive resin cement (Panavia 21). Retention was evaluated by measuring the tensile load required to dislodge the artificial crown from tooth preparations with an Instron testing machine, and analysed by one-way ANOVA and Student's t-test. The obtained results were as follows ; 1. When tooth preparation was done with coarse diamond bur, retentive force was diminished in order of Panavia 21 Fuji PLUS, FLECK'S, and Poly-F. Retentive forces showed the significant difference between Fuji PLUS group and FLECK'S group(p<0.001). 2. When tooth preparation was done with superfine diamond bur, retentive force was diminished in order of Fuji PLUS, Panavia 21, FLECK'S, and Poly-F. Retentive forces showed the significant difference between Panavia 21 group and FLECK'S group(p<0.001). 3. Retentive force in coarse tooth surfaces was significantly higher than that in superfine tooth surface with all luting cements(p<0.001), and cement residues were almost retained with-in the cast crown in all groups.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.268-274
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• 2023

In this case, a CAD-CAM complete denture that can be easily remanufactured and reduced the number of visits was decided in consideration of the fact that it was difficult to visit the dental hospital and many existing dentures were lost because the patient was inpatient in a nursing hospital. In order to reflect the shape, vertical dimension, and maxillomandibular relationship of the existing provisional dentures adapted by the patient to the fabrication of the final denture, the existing provisional dentures were scanned and closed mouth impression was taken with the printed individual tray. After digital facebow transfer using UTS CAD and arranging artificial teeth in CAD software, the maxillary and mandibular complete dentures were fabricated by milling the denture base and artificial teeth at once with the monolithic disc.

• Journal of Korean Dental Science
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• v.10 no.1
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• pp.29-34
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• 2017

Purpose: The purpose of this study was to evaluate the microleakage of various types of resin-bonded fixed partial dentures (RBFPDs) after artificial aging. Materials and Methods: Forty models with missing first molar were fabricated using artificial resin teeth and were divided into four groups: Group A, conventional RBFPDs design; Group B, modified RBFPDs design; Group C, assembled 3-piece RBFPDs design; and Group D, assembled 3-piece RBFPDs with different occlusal rest positions. Half of the specimens underwent chewing simulation process (240,000 cycles, 50 N load, 1.7 Hz) and thermocycling (temperatures $5^{\circ}C{\sim}55^{\circ}C$, dwelling time 30 seconds) and the remaining 20 specimens didn't receive any treatment. All the specimens were immersed in 2% methylene blue solution for 24 hours to evaluate microleakage, and were sectioned at the middle part of abutment teeth. To evaluate the microleaskage, a dye penetration was calculated. Result: With artificial aging, cyclic loading and thermocycling, a 3-piece RBPFD and a 2-piece RBPFD using original tooth undercuts have significantly lower microleakge (P<0.05) compared to the conventional design of RBPFD and modified RBPFD. Conclusion: Within the limit of this experiment, the assembled RBFPDs exhibited a smaller microleakage than the conventional RBFPDs, implying that the assembled RBFPDs can be more effective for reducing the dislodgement of the RBFPDs.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.397-404
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• 2019

Bone and soft tissue conditions are important for successful implant treatment. But, the placement itself is also very important. Implants which is installed in the wrong position result in the biological, esthetical and mechanical problems. In order to place an implant in the correct position, the final restoration and diagnostic wax-up should be considered prior to the surgery. If the artificial teeth for the interim denture are directly transferred from the diagnostic wax-up, the operator can try the form of diagnostic wax-up in the mouth. If the surgical template is produced by duplicating the interim denture, the implant can be placed in the planned position. In this case, the polymethyl methacrylate (PMMA) artificial tooth was precisely milled by the digital duplication of diagnostic wax-up. And interim denture was fabricated by using these milled teeth. After the patient adapted for a sufficient period, the implant was placed at the planned position with surgical template produced by duplicating the interim denture. After confirming sufficient osseointegration, the final prostheses were made to reflect the shape of diagnostic wax-up. Through this procedure, the satisfactory functional and esthetic outcome could be acquired.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.5
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• pp.508-515
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• 2011

Bovine incisor was investigated using active infrared thermography(IRT) to visualize crack on bovine teeth. An artificial crack was carefully created in bovine incisor sample by compression load of universal tensile machine. While applying a sinusoidal heat wave to the cracked bovine incisor through halogen lamp, consecutive digital infrared images was captured from the sample surface at a frequency synchronized with heat excitation. Phase information of thermal image was calculated by four-point correlation method and processed to produce the phase image of bovine incisor. This phase image showed clearly the crack on the incisor, which was hardly detected in traditional passive thermography.

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.483-496
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• 1993

Dentin hypersensitivity medicaments such as Gluma, Scotchbond 2, All-Bond 2, which are resin adhesives, were used to compare the sealing effects of dentinal tubule under mechanical stress. Topical application of above medicaments on the dentin surfaces of extracted teeth followed by artificial tooth brushing for 6 weeks was performed for the comparison. The following conclusions on the degree of dentinal tubule exposure versus time by were reached by using polyvinyl siloxane impression material for taking the impression, epoxy resin for the duplication and SEM for observing the surface. 1. SEM was used to compare the accuracy of the duplicated surface, but no differences were found when teeth samples and the duplicated surfaces were observed. 2. After comparing the degree of dentinal tubules exposure with varnish applied contrast group, resin adhesive materials showed much less exposure as time went by. 3. The results indicated that AU-Bond 2 adhesive, under mechanical stress, showed lesser exposure of dentinal tubules comparing with Gluma and Scotchbond 2 adhesives After the results were put together, it was demonstrated that resin replica method is an useful way to evaluate the treatment effects of the dentinal tubule hypersensitivity medicaments. Also, it was noticed that under mechanical stress, All-Bond 2, classified as fourth generation, illustrated the best dentinal tubules sealing effects.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.32 no.1
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• pp.8-15
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• 2023

In case with severely atrophied mandibular ridges, it may be difficult to achieve adequate retention and stability of dentures through the normal functional impression process of complete dentures. In these patients, an approach using the neutral zone raising technique may be an effective alternative. The neutral zone is defined as the area where the pressure of the tongue towards the outside of the mouth and the pressure of the cheek and lips towards the inside are balanced during the normal oral function of the muscular-nervous system. Complete dentures made through neutral zone impression not only improve retention and stability, but also provide adequate tongue space in the posterior teeth area. Additionally, food residues are reduced in the area around artificial teeth, and aesthetics are improved through appropriate facial support.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.3
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• pp.304-311
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• 2019

After the teeth were extracted, maxillary and mandibular alveolar ridges show the opposite resorption pattern and as a result, the mandibular arch is enlarged than maxillary arch relatively. In this situation, we should evaluate both alveolar ridge relationship and arrange the artificial teeth properly for stability of removable prosthesis. This case is a 77 years old male patient who wishes to make removable prosthesis and has atrophic alveolar ridge. By use of model scanner and CAD software, the angle between interalveolar crest line and occlusal plane was easily measured. Depending on the measurement, the artificial teeth are arranged in unilateral cross bite and after completion, patient was satisfied with the denture which showed proper stability, retention, support.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.202-210
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• 2022

Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.

• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.454-461
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• 2004

The purpose of this study is to compare and to evaluate the effects of the degree of saturation on the progression of artificial root caries lesion. A total of 8 human premolars without any defects and cracks selected and the cementum were removed and the teeth were cleaned with ultrasonic device and pumice without fluoride. Each tooth was sectioned into 6 pieces and they were ground with #800 sandpaper until they had a thickness of 200pm. Specimens were applied with nail vanish except for the 2-3 mm window area after application of bonding agent. Under the constant pH, the specimens were divided into 6 groups (degree of saturation: 0.1415, 0.1503, 0.1597, 0.1676, 0.1771. 0.1977). Each group was immersed in acid buffer solution for 1. 2, 3, 5 days under controlled temperature ($25^{\circ}C$) and imbibed in water and examined using the polarizing microscope. The results were as follows 1. Although the degree of saturation of demineralization solution decreased, the depth of penetration in the dentin was constant. 2. Erosion was observed on the surface of all the teeth in the group I, II. In the group III, IV, V, surfaces were not changed. The teeth in the group VI showed the more mineralized surface but not the shape of the dentinal tubules distinctively. 3. In all groups, the lesion progressed rapidly at the first day of the experiment, but increased gradually as time elapsed.