Earticle

Purpose: Dental casting #GrⅠ(Co-25Cr-5Mo-3Sn-1Mn-1Si), #GrⅡ(Co-25Cr-5Mo-5Cu-1Mn -1Si) and #GrⅢ (Co-25Cr-5Mo-3Sn-5Cu-1Mn-1Si) master alloys of granule type were manufactured the same as manufacturing processes for dental casting Ni-Cr and Co-Cr-Mo based alloys of ingot type. These alloys were analyzed melting processes with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer. Methods: These alloys were manufactured such as; alloy design, the first master alloy manufatured using vacuum arc casting machine, melting metal setting in crucible, melting in VIM, pouring in the mold of bar type, cutting the gate and runner bar and polishing. These alloys were put about 30g/charge in the ceramic crucible of high frequency induction centrifugal casting machine and heat, Infrared thermal image analyzer indicated alloys in the crucible were set and operated. Results: The melting temperatures of these alloys measuring infrared thermal image analyzer were decreased in comparison with remaniumⓇ GM 800+, vera PDITM, BiosilⓇ f, WISILⓇ M typeⅤ, Ticonium 2000 alloys of ingot type and vera PDSTM(Aabadent, USA), Regalloy alloys of shot type. Conclusion: Co-Cr-Mo based alloy in addition to Sn(#GrⅠ alloy) were decreased the melting temperature with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer.

Purpose: Dental casting Co-Cr-Mo based alloys of five kinds of ingot type and two kinds of shot type were analyzed the melting processes with heating time of high frequency induction centrifugal casting machine using infrared thermal image analyzer. Methods: When Co-Cr-Mo based alloys were put about 30g/charge in the ceramic crucible of high frequency induction centrifugal casting machine and heat, Infrared thermal image analyzer and IR thermometer indicated these alloys in the crucible were set and operated. Results: The melting temperatures of alloys measuring infrared thermal image analyzer were deviated ±10℃ compared to those of manufacturing company. On the other hand, the melting time of alloys were differently appeared with the shape of alloys(ingot and shot type). Conclusion: The melting temperatures of dental Co-Cr-Mo based alloys were measured the degree of 1,360~1410℃ and the heating time with the alloys of ingot and shot type were deviated ±10 sec.

Purpose: The purpose of this study was analysis of quality of fixed prostheses fabricated by dental CAD/CAM system. Methods: The ten same cases of stone models were manufactured by dental scannable model, and stone models were scanned using the dental scanner for changing digital model. Ten digital models were completed. The design of zirconia core for zirconia based all-ceramic crown was conducted by the dental CAD program. The samples were fabricated using the pre-sintered zirconia block by dental milling machine. Marginal gaps were analyzed using by silicone replica technique at the eight parts for quality analysis of samples. One-way ANOVA was used for statistical analysis(a =0.05). Results: The mean for marginal gaps were 93.2~99.1㎛ at the eight parts. One-was ANOVA didn’t show significant differences(p=0.089). Conclusion: The fixed dental prostheses fabricated by dental CAD/CAM were within clinically acceptable range.

Purpose: This study is a mechanical strength supplementation of denture base resin Polymethyl methacrylate (PMMA) is in general use for denture base resin of the partial and full denture, however, The polymerization process of PMMA is not stabilized. Because of compatibility problems, preceding studies were performed, which were enhancing mechanical strength(Camilo Machado 2007),(Ana M. 2008), addition filler to materials property(Ayse Mese, 2008), self curing method(Hiroshi Shimizu, 2008). Methods: The carbon fiber and polyacetal filler, reinforced the mechanical strength for improving the stability of denture base resin were supplemented to the self cured resin. The Modulus of elasticity and the restoring force were calculated by tensile test. Results: The strengths of the heat and self cured resin were respectively decreased and increased, when the filler was supplemented to the denture base resin and the modulus of elasticity of both heat and self cured resin were not increased, when the filler was supplemented to the denture base resin. Conclusion: The restoring forces of self cured resin containing 10% filler were increased, when the filler was supplemented to the denture base resin.

Purpose: The dental medicine has been preparing the custom-made service to meet the requirements of the aged society, while the average span of human life is growing more and more, and the full denture is a representative of them. It is causing great concern in these atmosphere of society, and demands for it are expected to increase. The full denture is a uniform combination of denture base and artificial teeth using polymerization, and is most influenced by change of physical properties of denture base and bonding strength with artificial teeth. Methods: In this study, the samples were made of composite resin combined with occlusion surface of artificial teeth undergone mechanically surface treatment to evaluate the bonding strength of composite resin for repairing artificial teeth. The resin teeth used in this study are 3 types artificial teeth. And 3 types of composite resins are used that are various polymerization resin . The shear strength of composite resins made in various polymerization ways to resin teeth was measured to evaluate bonding strength of artificial teeth to each composite resins. Results: Surface hardness’s results on Trubyte Biotone(74.58Hv), Biotone IPN(70.06Hv), Endura Posterio (64.48Hv). Results of bonding strength of artificial teeth to composite resins on ES samples(8.73 ), IF(4.37 ) and IZ(3.84 ). Conclusion: 1. The Trubyte Biotone(74.58Hv) was first, followed by Biotone IPN(70.06Hv), and Endura Posterio(64.48Hv) in surface hardness’s results of worn sides using hardness test. 2. The ES samples(8.73 ) showed significant differences with IF(4.37 ) and IZ(3.84 ) (p<0.05), but not other samples(p>0.05) in results of bonding strength of artificial teeth to composite resins.

Purpose: This study was performed to investigate the release behavior of bioactive materials as a BMP-2 embedding on the porous titanium implant. Methods: Porous Ti implant samples were fabricated by sintering of spherical Ti powders in a high vacuum furnace. Specimens diameter and height were 4㎜ and 10㎜. Embedding materials were used to stamp ink. Sectional images, porosity and release behavior of porous Ti implants were evaluated by scanning electron microscope(SEM), mercury porosimeter and UV-Vis-NIR spectrophotometer. Results: Internal pore structure was formed fully open pore. Average pore size and porosity were 8.993㎛ and 8.918%. Embedding materials were released continually and slowly. Conclusion: Porous Ti implant was fabricated successfully by sintering method. Particles are necking strongly each other and others portions were vacancy. Therefore bioactive materials will be able to embedding to porous Ti implants. If the development of the fusion implant of the bioactive material will be able to have the chance to several patients.

Purpose: This study aims to examine correlation between temporomandibular disorder and oral habits that have been known to cause temporomandibular disorder with both male and female undergraduates. Methods: To figure out correlation between temporomandibular disorder and oral habits, a survey was conducted to 500 students of two universities located in Daegu Metropolitan City and Gyeongsangbuk-do, and excluding the ones unreliably answered or indicating errors, total 427 (85.4%) out of 500 questionnaire sheets were used for final analysis. Results: Female students showed higher prevalence rates than male students in temporomandibular joint pain and temporomandibular joint clicking, and students having the lip biting habit, tongue thrust habit, or bruxism habit indicated a higher prevalence rate of temporomandibular joint pain than normal students. Also, students having the tongue thrust habit indicated a significantly higher prevalence rate of temporomandibular joint clicking than normal students not having it. And about trismus, students having the bruxism habit showed a significantly higher prevalence rate than normal students not having it. Conclusion: The findings imply that oral habits like lip biting, tongue thrust, or bruxism are closely related with temporomandibular joint pain, tongue thrust influences temporomandibular joint clicking, and bruxism does affect trismus.

Purpose: The purpose of this study was to evaluate oral health status according to use of oral care products in the adult population and determine methods for improving oral health status. Methods: The date of ‘The fifth korean national health and nutrition examination survey 2011’ was analyzed for this study. The questionnaire was measured regarding oral care products, Oral health status and socio-economic characteristics. For statistical analysis, the Statistical Package for Social Sciences version 19.0 for Windows was used. We determined frequencies, percentage and determining statistical significance using multiple regression analysis. Results: General characteristics and oral care products showed differences in DMFT associated with residence, gender, age, education, dental floss, etc(waterpic, hi-tech toothbrush, denture care products), in FS-T associated with residence, gender, age, income level, education, health insurance, dental floss, Interdental brush, etc, in Thealth associated with residence, age, education, health insurance, Interdental brush, etc. Conclusion: In conclusion, in order to promote oral health status of the adult have to suitable selection and accurate usage of oral care products. Education and program in oral care products for the adult should be needed.

Purpose: This study will examine the differences among the college dental morphology textbooks in light of their contents and learning objectives through which we will propose an optimal way of consolidating those differences found. Methods: Five college textbooks adopted in the dental related departments were selected by random and the overview and subdivisions of contents were compared and closely analysed with regards to the learning objectives. Results: Firstly, all of the dental morphology textbooks cover the learning objectives of the dental morphology subject, especially in the area of the overview of dental morphology, the permanent tooth, deciduous tooth. Only the dentistry textbooks explain the learning objective of the occlusion. Secondly, differences in content were found in the area of component tissue and around tissue, dental formula of deciduous teeth, spinous process, buccal pit, enamel projection, curve symbol, tip of cusp position of proximal surface of permanent mandibular canines, buccal cusp position of permanent mandibular second premolars. Conclusion: It is imperative to delineate some meaningful and critical differences in contents among the dental morphology textbooks and reflect this to each and every textbook to be published as a supplementary information guide or index.