PURPOSE: We aimed to identify a more esthetic width-to-length ratio by analyzing maxillary central incisor of Korean adult population. Information regarding tooth ratio in the Korean population may be useful to clinicians when restoring anterior teeth. MATERIALS AND METHODS: A total of 40 men and 40 women were included in this study. The NON-MEDIA group included 40 non-celebrities, who were healthy and 25 to 39 years old, with normal dentofacial appearance. The MEDIA group consisted of 40 celebrities selected only on the basis of their soft-tissue facial appearance. The facial photographs of 40 celebrities were collected from the Internet websites. The width and length of the maxillary central incisor were measured using Adobe Photoshop(R) 7.0, a software for analysis, measurement and edition of photographs. Data were analyzed statistically using the Independent t-test at 5% statistical significance level. RESULTS: The mean ratio for the MEDIA group was 0.77, whereas that of the NON-MEDIA group was 0.88. The difference between the two groups was statistically significant. No significant gender differences were found in the width-to-length ratio in MEDIA group. In NON-MEDIA group, however, there were significant differences between female and male. CONCLUSION: After analyzing maxillary anterior teeth of Korean adults, our results were in accordance with the general Western standards of esthetics. A dentist restoring the natural look and beauty of teeth will have to consider those standards.
Adult ; Anodontia ; Beauty ; Dentists ; Esthetics ; Female ; Humans ; Incisor ; Internet ; Korea ; Male ; Tooth

PURPOSE: We aimed to identify a more esthetic width-to-length ratio by analyzing maxillary central incisor of Korean adult population. Information regarding tooth ratio in the Korean population may be useful to clinicians when restoring anterior teeth. MATERIALS AND METHODS: A total of 40 men and 40 women were included in this study. The NON-MEDIA group included 40 non-celebrities, who were healthy and 25 to 39 years old, with normal dentofacial appearance. The MEDIA group consisted of 40 celebrities selected only on the basis of their soft-tissue facial appearance. The facial photographs of 40 celebrities were collected from the Internet websites. The width and length of the maxillary central incisor were measured using Adobe Photoshop(R) 7.0, a software for analysis, measurement and edition of photographs. Data were analyzed statistically using the Independent t-test at 5% statistical significance level. RESULTS: The mean ratio for the MEDIA group was 0.77, whereas that of the NON-MEDIA group was 0.88. The difference between the two groups was statistically significant. No significant gender differences were found in the width-to-length ratio in MEDIA group. In NON-MEDIA group, however, there were significant differences between female and male. CONCLUSION: After analyzing maxillary anterior teeth of Korean adults, our results were in accordance with the general Western standards of esthetics. A dentist restoring the natural look and beauty of teeth will have to consider those standards.
Adult ; Anodontia ; Beauty ; Dentists ; Esthetics ; Female ; Humans ; Incisor ; Internet ; Korea ; Male ; Tooth

Purpose: The purpose of this study is to evaluate the antimicrobial activity on the dental bur with fluoride for S. mutans. Materials and methods: 0 ppm, 300 ppm, 500 ppm, 1,000 ppm, 1,450 ppm fluoride ion is added to a specimen. S. mutans was incubated for 24 hours, the number of S. mutans were counted. Kruskal-Wallis and Mann- Whitney analysis were used SPSS 25.0 (IBM SPSS 25.0, Chicago, IL, USA). Results: The mean S. mutans counts of 0 ppm, 300 ppm, 500 ppm, 1,000 ppm, and 1,450 ppm were 374.0 ± 12.6, 251.0 ± 66.7, 111.4 ± 35.6, 41.6 ± 11.7 and 13.2 ± 4.6, respectively. All groups except the control and 300 ppm showed statistically significant. Conclusion Thus, more than 500 ppm fluoride ion showed the statistically significant antimicrobial activity. 1,450 ppm group showed the highest antimicrobial activity. This study showed the clinical possibility for dental caries protection and antimicrobial activity of dental bur.

Increasing the vertical dimesion affects not only functional problems but also the facial appearance. In particular, when restoring the reduced vertical dimension, it is important to evaluate facial appearance because the change affects the patient’s aesthetics. Cephalometric radiographs can predict changes in the facial appearance through skeletal and vertical classifications using anatomical indicators, and the changes before and after treatment can be easily observed, which could serve as good data in evaluating treatment success. In this study, comparative evaluation was performed through cephalometric radiography, and the aesthetic and functional improvement was confirmed.

PURPOSE: The purpose of this study was to find an inclination slope of the screw thread that is favorable in distributing the stresses to alveolar bone by using three dimensional finite element analysis. MATERIALS AND METHODS: Three types modelling changed implant thread with fixed pitch of 0.8 mm is the single thread implant with 3.8degrees inclination, double thread implant with 7.7degrees inclination and the triple thread implant with 11.5degrees inclination. And three types implant angulation is the 0degrees, 10degrees and 15degrees on alveolar bone. The 9 modelling fabricated for three dimensional finite element analysis that restored prosthesis crown. The crown center applied on 200 N vertical load and 15degrees tilting load. RESULTS: 1. The more tilting of implant angulation, the more Von-Mises stress and Max principal stress is increasing. 2. Von-Mises stress and Max principal stress is increasing when applied 15degrees tilting load than vertical load on the bone. 3. When the number of thread increased, the amount of Von-Mises stress, Max principal stress was reduced since the generated stress was effectively distributed. 4. Since the maximum principal stress affects on the alveolar bone can influence deeply on the longevity of the implants. When comparing the magnitude of the maximum principal stress, the triple thread implant had a least amount of stress. This shows that the triple thread implant gave a best result. CONCLUSION: A triple thread implant to increase in the thread slope inclination and number of thread is more effective on the distribution of stress than the single and double thread implants especially, implant angulation is more tilting than 10degrees on alveolar bone. Thus, effective combination of thread number and thread slope inclination can help prolonging the longevity of implant.
Crowns ; Finite Element Analysis ; Longevity ; Prostheses and Implants

Patients with Sjögren's syndrome usually suffer from teeth discoloration and attrition due to xerostomia. If the anterior teeth are badly worn, problems such as loss of anterior guidance, occlusal disharmony, and limited space for restoration may occur. However, ideal occlusion is obtained in both centric and eccentric relation by regaining the disocclusion of the posterior teeth through the anterior and lateral guidance using twin-stage method. In this case, rehabilitation was performed for a Sjögren's syndrome patient with maxillary and mandibular incisor's severe attrition and teeth discoloration by using twin-stage method.
Dental Occlusion ; Humans ; Methods* ; Rehabilitation* ; Tooth* ; Xerostomia

Patients with Sjögren's syndrome usually suffer from teeth discoloration and attrition due to xerostomia. If the anterior teeth are badly worn, problems such as loss of anterior guidance, occlusal disharmony, and limited space for restoration may occur. However, ideal occlusion is obtained in both centric and eccentric relation by regaining the disocclusion of the posterior teeth through the anterior and lateral guidance using twin-stage method. In this case, rehabilitation was performed for a Sjögren's syndrome patient with maxillary and mandibular incisor's severe attrition and teeth discoloration by using twin-stage method.
Dental Occlusion ; Humans ; Methods* ; Rehabilitation* ; Tooth* ; Xerostomia

STATEMENT OF PROBLEM: It is known that an anodic oxidation technique, one of the methods for the implant surface treatment, remarkably increased surface area, enhanced wettability and accelerated the initial bone healing. Purpose: This study was performed to evaluate the wettability of anodized titanium surface which has a nanotubular structure, to assess osseointegration after the placement of implant with nano-size tubes on tibia of rats and to analyze quantitatively transferable rhBMP-2 on each surface. MATERIAL AND METHOD: Four different kinds of surface-treated titanium discs (polished (machined surface) group, micro (blasting surface) group, nano (anodizedmachined surface) group, and nano-micro (anodized-blasting surface) group) were fabricated (n=10). Three different media were chosen to measure the surface contact angles; distilled water, plasma and rhBMP-2 solution. After a single drop (0.025 ml) of solution, the picture was taken with the image camera, and contact angle was measured by using image analysis system. For the test of osseointegration, 2 kinds of anodized surface (anodized-machined surface, anodized-blasting surface) implants having 2.0 mm in diameter and 5.0 mm in length inserted into the tibia of Wistar rats. After 3 weeks, tibia were harvested and the specimens were stained with hematoxylin and eosin for histological analysis. To test the possibility of drug delivery, after soaking sample groups in the concentration of 250 ng/ml of rhBMP-2 for 48 hours, the excess solution of rhBMP-2 were removed. After that, they were lyophilized for 24 hours, and then the rhBMP-2 on the surface of titanium was resolved for 72 hours in PBS. All the extracted solution was analyzed by ELISA. One-way analysis of variance (ANOVA) was performed on the data. RESULTS: The wettability is improved by anodic oxidation. The best wettability was shown on the nano-micro group, and it was followed by nano group, micro group, and polished group. In the histological findings, all implants showed good healing and the new bone formation were observed along the implant surface. After 3 days, nano-micro group delivered the most amount of rhBMP-2, followed by nano group, micro group, and polished group. CONCLUSION: It indicated that anodic oxidation on blasting surface produce functionally graded nano-micro porous structure and enhance hydrophilicity of the surface and osseointegration. The findings suggest that the nano-micro porous structure could be a useful carrier of osteogenic molecules like rhBMP-2.
Animals ; Durapatite ; Enzyme-Linked Immunosorbent Assay ; Eosine Yellowish-(YS) ; Hematoxylin ; Hydrophobic and Hydrophilic Interactions ; Osseointegration ; Osteogenesis ; Plasma ; Rats ; Rats, Wistar ; Tibia ; Titanium ; Water ; Wettability

PURPOSE: The purpose of this study was to compare the linear sintering behavior of presintered zirconia blocks of various densities. The mechanical properties of the resulting sintered zirconia blocks were then analyzed. MATERIAL AND METHODS: Three experimental groups of dental zirconia blocks, with a different presintering density each, were designed in the present study. Kavo Everest(R) ZS blanks (Kavo, Biberach, Germany) were used as a control group. The experimental group blocks were fabricated from commercial yttria-stabilized tetragonal zirconia powder (KZ-3YF (SD) Type A, KCM. Corporation, Nagoya, Japan). The biaxial flexural strengths, microhardnesses, and microstructures of the sintered blocks were then investigated. The linear sintering shrinkages of blocks were calculated and compared. RESULTS: Despite their different presintered densities, the sintered blocks of the control and experimental groups showed similar mechanical properties. However, the sintered block had different linear sintering shrinkage rate depending on the density of the presintered block. As the density of the presintered block increased, the linear sintering shrinkage decreased. In the experimental blocks, the three sectioned pieces of each block showed the different linear shrinkage depending on the area. The tops of the experimental blocks showed the lowest linear sintering shrinkage, whereas the bottoms of the experimental blocks showed the highest linear sintering shrinkage. CONCLUSION: Within the limitations of this study, the density difference of the presintered zirconia block did not affect the mechanical properties of the sintered zirconia block, but affected the linear sintering shrinkage of the zirconia block.
Cyclic N-Oxides ; Zirconium

PURPOSE: The purpose of this study is to fabricate the new zirconia block (CNU block) and to evaluate fit of core and porcelain veneered zirconia crown. MATERIAL AND METHODS: The experimental blocks were fabricated from the commercial ytrria-stabilized zirconia powder (KZ-3YE Type A). The powder was uniaxial pressing and the green bodies were conducted using the Cold Isostatic Pressing. The zirconia blocks were presintered at 1040degrees C and the final sintering was performed at 1450degrees C. The Kavo Everest ZS blank(R) (KaVo, Biberach/Ri beta.) was used as a control group. The linear shrinkage of CNU block and Kavo block were compared. Twenty-one cores for porcelain veneered crowns were fabricated with CAD/CAM system (Everest(R), Biberach/Ribeta.). Group I: seven cores fabricated from Kavo blocks, Group II: seven cores fabricated from CNU blocks, Group III: seven cores from CNU blocks and porcelain veneering for crowns. All specimens were cemented and sectioned into two planes: diagonal and bucco-lingual. The measurement of the marginal, internal, and occlusal fit was carried out using SEM (S-4800(R)) at 30 x. The results were analyzed by one-way ANOVA test. RESULTS: The linear shrinkage of the CNU block and the KaVo block was 19.00% and 20.09%. The marginal gap of cores (29.67 +/- 6.58 micrometer) fabricated from CNU blocks showed significantly smaller than that of the cores of Kavo blocks (36.84 +/- 7.18 micrometer) (P < .05). The internal gaps of the porcelain veneered crowns (32.23 +/- 6.33 micrometer) were larger than those of the other two groups (37.57 +/- 6.81 micrometer and 38.14 +/- 6.81 micrometer). CONCLUSION: No statistically significant difference was found in between experimental groups and control group. The experimental groups in marginal gap showed significantly smaller than the control group.
Cold Temperature ; Crowns ; Dental Porcelain ; Ethylnitrosourea ; Zirconium