No abstract available.
Crowns* ; Dental Porcelain*

For the improvement of denture fitness of changed residual ridge, denture liner can be used. Denture liner should be very stable physically in various environments of the mouth as well as be bonded strongly with denture resin. In this study, the specimens bonded with four kinds of soft denture liner and three kinds of hard denture liner were used to test the physical properties of the liners. All experimental groups were stored in 37+/-1degrees C distilled water for 24hours, followed by thermocycling between 15degrees C and 45degrees C with 15 second dwell time. 1000, 2000, 3000 cycles of thermocycling were excuted and physical properties were measured by Instron Universal Testing Machine. The obtained results were as follows: 1. In tensile bond test of soft liners, it was shown that both of Molloplast-B(R) specimens before and after thermocycling had the highest tensile strength, and in case of hard liners, Dura-liner II(R)speimen had the highest tensile strength before and after thermocycling. Depending on thermocycling, Soft-Relining(R), Denture-Relining(R),Molloplast-B(R), Coe-soft(R) and Kooliner(R) specimen showed significant difference(p<0.05). 2. In strain test of soft liners, it was shown that Molloplast-B(R) specimen before thermocycling and the Coe-soft(R) after thermocycling showed highest results, and in case of hard liners, the Dura-Liner II(R) speimen before and after thermocycling had the highest result. Depending on thermocycling. Denture-Relinig(R). Molloplast-B(R) and Dura-Lner II(R) specimen showed significant difference(p<0.05). 3. In Maximum distance test of soft liners, the Molloplast-B(R) specimen before thermocycling and the Coe-soft(R) after thermocycling showed highest results, and in case of hard liners, the Dura-Liner II(R) specimen before and after thermocycling showed highest results. Depending on thermocycling, Denture-Relining(R), Molloplast-B(R) specimens showed significant difference(p<0.05). 4.In elasticity test of soft liners , the Molloplast-B(R) specimen before and after thermocycling showed highest results, and in case of hard liners, the Dura-Liner II(R) specimen before thermocycling and the Tokuso-Rebase (R) after thermocycling showed highest results. Depending on thermocycling, Soft-Relining(R) , Molloplast-B(R) specimens showed significant difference(p<0.05).
Denture Liners* ; Dentures* ; Elasticity ; Mouth ; Tensile Strength ; Water

The purpose of this study is to compared and analyze the shade changes(deltaE)about In-Ceram(R),IPS-Empress(R),OPC(R) by using of the spectrophotometer arising from initial status and before and after cementation of the resin cement mounted on the metal core. We used a couple of statistics such as 'One-Way ANOVA'and Multiple Range Test. We could be able to verify significantly what is being discussed here up to 95%. The results drawn from our research are as follows: 1. At the time of our experiments regarding the initial shapes of all-ceramic and mounting status of all-ceramic on the metal crown(deltaE1), and a comparison of mounting of all ceramic on the metal crown with all-ceramic cemented on the metal core(deltaE2), at the time of shade change of initial shapes and after we cemented on the metal core. (1) no significant difference among all-ceramics was found. (2) no particular difference was found regarding the In-Ceram(R) (3) a significant difference between the deltaE1 and deltaE2 regarding the IPSS-Empress(R) was found (P<0.05). (4) a significant difference between the deltaE1 and deltaE2 regarding the OPC? was found (P<0.05). 2. When we compared the shade changes (deltaE) resulted from before and after the cementation on each of the parts involved of some all-ceramic . we could be able to find shape change increase from incisal third, middle third, and cervical third in that order in In-Cream(R)(spinell), IPS Empress(R) and OPC(R) all. In addition , we could be able to find a siginificant difference between cervical third and incisal third, middle third. (P<0.05) From what we have just seen, we might conclude that there is a significant shade change difference before and after the cementation with respect to IPS-Empress(R)and OPC(R). In addition, we could also be able to find more shade change difference at the cervical third rather than incisal third and middle third depending on the parts involved.
Cementation ; Ceramics* ; Crowns* ; Resin Cements

STATEMENT OF PROBLEM: For a long time, many of denture base acrylic resins have been used for edentulous and partial edentulous patients because of easy manipulation and good mechanical properties, but its esthetic aspect has not been commented enough. Denture base acrylic resins also has caused esthetic problems due to discoloration or staining as in esthetic restoration. Many researches and reports have treated the problems and accomplished esthetic improvement. But these researches and reports dealt with general food colors or beverages, not with fermented foods. PURPOSE: This study is designed to assess what fermented foods, such as soy sauce, gochujang, and toenjang that many of Koreans have taken in, influence on the color and hardness variation of denture base acrylic resins. MATERIALS AND METHODS: For the procedure, twelve disks per 4 denture base acrylic resins were fabricated with a thickness of 2mm and 16mm in diameter. Each seven specimen were measured for discoloration with spectrophotometer, while the others, five specimen, for surface hardness change with Barcol hardness tester, over time. Each 12 specimen were immersed into the 4 beakers of fermented foods(soy sauces, gochujangs, toenjangs, deionized water), and L*, a*, and b* values were measured for the color difference(_E*), on the 1st, 7th, and 28th day with spectrophotometer, with the measurement of surface hardness change. Each data observed was processed statistically. RESULTS: The findings are as follows; Discoloration 1. All of denture base resins was not influenced by the kind of fermented foods, except for QC20. 2. Soy sauce and red pepper paste caused more change for denture base resins than deionized water and soy bean paste, except for Perform. 3. Most significant change was shown in Lucitone199., whereas Perform. results in the least change for all immersed solution, with no statistical significance. Hardness change 1. Barcol hardness values in deposited specimens have been changed low degree, but with significant statistical change according to the kind of food and duration. 2. Lucitone199. has significantly lower Barcol hardness value than others do. CONCLUSION: Based on the above results, it suggests that the habitual intake of fermented foods is not helpful for the color stability of denture base acrylic resins because Soy sauce and red pepper paste mainly caused discoloration and surface hardness change. Particularly Lucitone199. shows specific discoloration and low surface hardness values. Therefore, it is recommended giving caution patients with denture of Lucitone199. especially against the habitual intake of fermented foods like soy sauce and red pepper paste.
Acrylic Resins* ; Beverages ; Capsicum ; Denture Bases* ; Dentures* ; Hardness Tests ; Hardness* ; Humans ; Soy Foods ; Soybeans ; Water

Novel methods producing supplementary and prosthetic material by cutting or discharge processing via computer design have been proposed as alternatives for traditional casting methods and are being utilized for commercial purposes. The CAD/CAM system used in dentistry can be classified into three-dimensional input of target values, restoration design, and material processing. The marginal fidelity in production of In-Ceram core has important clinical implications and is a key consideration issue in CAD/CAM production as well. Through this research, the author arrived at the following conclusion after conducting comparison analysis of marginal fidelities between the In-Ceram core produced via CAD/CAM and that produced through the traditional method: 1. In the cases of mesial, distal, and lingual margins, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 2. In the case of labial flange, the core margins via CAD/CAM produced lower values than those via the traditional method and the differences were found to be statistically significant. (p<0.05) 3. In comparision with overall marginal fidelity, the core margins via CAD/CAM produced lower values than those via the traditional method, but the differences were found to be statistically insignificant. 4. Among the core margins produced via the traditional method did not have statistically significant differences but for those produced via CAD/CAM had statistically significant differences between labial and lingual sides and between labial and mesial sides. (p<0.05)
Dentistry

STATEMENT OF PROBLEM: Successful osseointegration of endosseous threaded implants is dependent on many factors. These may include the surface characteristics and gross geometry of implants, the quality and quantity of bone where implants are placed, and the magnitude and direction of stress in functional occlusion. Therefore clinical quantitative measurement of primary stability at placement and functional state of implant may play a role in prediction of possible clinical symptoms and the renovation of implant geometry, types and surface characteristic according to each patients conditions. Ultimately, it may increase success rate of implants. PURPOSE: Many available non-invasive techniques used for the clinical measurement of implant stability and osseointegration include percussion, radiography, the Periotest., Dental Fine Tester. and so on. There is, however, relatively little research undertaken to standardize quantitative measurement of stability of implant and osseointegration due to the various clinical applications performed by each individual operator. Therefore, in order to develop non-invasive experimental method to measure stability of implant quantitatively, the resonance frequency analyzer to measure the natural frequency of specific substance was developed in the procedure of this study. MATERIAL AND METHOD: To test the stability of the resonance frequency analyzer developed in this study, following methods and materials were used: 1) In-vitro study: the implant was placed in both epoxy resin of which physical properties are similar to the bone stiffness of human and fresh cow rib bone specimen. Then the resonance frequency values of them were measured and analyzed. In an attempt to test the reliability of the data gathered with the resonance frequency analyzer, comparative analysis with the data from the Periotest was conducted. 2) In-vivo study: the implants were inserted into the tibiae of 10 New Zealand rabbits and the resonance frequency value of them with connected abutments at healing time are measured immediately after insertion and gauged every 4 weeks for 16 weeks. RESULTS: Results from these studies were such as follows: The same length implants placed in Hot Melt showed the repetitive resonance frequency values. As the length of abutment increased, the resonance frequency value changed significantly (p<0.01). As the thickness of transducer increased in order of 0.5, 1.0 and 2.0 mm, the resonance frequency value significantly increased (p<0.05). The implants placed in PL-2 and epoxy resin with different exposure degree resulted in the increase of resonance frequency value as the exposure degree of implants and the length of abutment decreased. In comparative experiment based on physical properties, as the thickness of transducer increased, the resonance frequency value increased significantly(p<0.01). As the stiffness of substances where implants were placed increased, and the effective length of implants decreased, the resonance frequencies value increased significantly (p<0.05). In the experiment with cow rib bone specimen, the increase of the length of abutment resulted in significant difference between the results from resonance frequency analyzer and the Periotest.. There was no difference with significant meaning in the comparison based on the direction of measurement between the resonance frequency value and the Periotest. value (p<0.05). In-vivo experiment resulted in repetitive patternes of resonance frequency. As the time elapsed, the resonance frequency value increased significantly with the exception of 4th and 8th week (p<0.05). CONCLUSION: The development of resonance frequency analyzer is an attempt to standardize the quantitative measurement of stability of implant and osseointegration and compensate for the reliability of data from other non-invasive measuring devices. It is considered that further research is needed to improve the efficiency of clinical application of resonance frequency analyzer. In addition, further investigation is warranted on the standardized quantitative analysis of the stability of implant.
Humans ; Osseointegration ; Percussion ; Rabbits ; Radiography ; Ribs ; Tibia ; Transducers

STATEMENT OF PROBLEM: Ceramic and composite resin have been used to fulfill the demand for esthetic prosthesis. However, ceramic is easy to break and wears off the opposite natural teeth. Conventional composite resin also has low abrasive resistance and color stability. Ceramic Optimized Polymer (ceromer) was developed in mid-1990s to overcome the shortfalls of ceramic and composite resin. Ceromer has similar abrasiveness with the natural tooth and has relatively high strength. Color stability affects esthetics and long-term prognosis of the prosthesis. PURPOSE: The purpose of this study was to compare color stability of ceromers(2 types : Artglass., Targis.) with ceramics(Vintage.-polishing, Vintage.-glazing). MATERIAL AND METHOD: The color difference(E*) was measured by spectrophotometer with different immersion time. Twenty disks, 3mm in thickness and 10mm in diameter, were fabricated for each specimen in shade A2(Vita Lumin shade guide). Specimens(5 samples in each group) were immersed in the food colorants(Red no.3, Yellow no.4, Blue no.1, Distilled water) for 24 hours, 48 hours and 72 hours respectively. L*, a* and b* value were measured with spectrophotometer (CM 503i : Minolta Co., Japan) and mean E* value was calculated for statistical analysis. RESULTS: The results of this study were obtained as follows. 1. The E* values of all test samples increased with the time of immersion. 2. The E* values of all materials increased in order of Distilled Water, Yellow no.4, Blue no.1 and Red no.3. There was significant difference between Red no.3 and the other food colorants(p<0.05). 3. The E* values increased in order of Vintage-glazing, Vintage-polishing, Artglass and Targis. There was significant difference between Vintage.-glazing and the other materials (p<0.05). CONCLUSION: By means of the above results, immersion time was found to be a critical factor for color stability of ceromer. For the long-term color stability of prosthesis it is recommended patients having ceromer prosthesis(Artglass., Targis.) to reduce the habitual intake of Red no.3 colorants con taining foods.
Ceramics ; Esthetics ; Food Coloring Agents* ; Humans ; Immersion ; Polymers ; Prognosis ; Prostheses and Implants ; Tooth ; Water

STATEMENT OF PROBLEM: Among the physical properties of adhesion luting cement, the aspect that requires the most important factor is the degree of solubility and water sorption. Dissolution or an inadequate due to excessive water sorption inside the oral cavity compromises the while concurrently increasing the susceptibility to secondary dental caries. Susceptibility to dissolution and difficulty of removing remnant cement from the gingival sulcus have hindered the use of dental resin cement in the clinical practice, but the improved characteristics of newer generation resin cements have interest in and enabled resin cements to be widely used in adhesion of fixed prosthesis, such as laminate veneers and all-ceramic crowns. PURPOSE: The purpose of this study is to compare and analyze the degrees of solubility and water sorption of a variety of resin cements widely used for clinical purposes with different curing methods. MATERIALS AND METHODS: Self-curing resin cements, Avanto(R), CandB(TM) CEMENT and Superbond CandB cements comprised group 1, 2 and 3. The dual-curing resin cements Panavia(TM) F, Calibra(R) and Variolink(R) II were divided into groups 4, 5, and 6, respectively. The investigation was carried out using disc-shaped specimens as specified by ANSI/ADA Specification No. 27. The degree of water sorption, water solubility and lactic acid solubility of each test group was analyzed statistically leading to the following conclusion. RESULTS: The degree of water sorption was shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. There were significant differences between the water sorption of each group. Results of the degree of water solubility were shown to increase in the following order : group 6, 5, 4, 2, 1 and 3. Statistically significant differences were found between each group, with the exception of groups 1 and 3. Finally, the degree of lactic acid solubility was found to increase in the following order : group 6, 5, 4, 2, 3 and 1. Significant differences were found between each group. In general dual-curing resin cements displayed substantially lower values than self-curing resin cements with regard to water sorption, water solubility, and lactic acid solubility. CONCLUSIONS: From the results of this study, dual-curing resin cements show a significantly lower degree of water sorption and solubility than their self-curing counterparts. Clinically, when selecting resin cements, the product with a lower degree of water sorption and solubility are preferred. The results of this study indicate that the use-of dual-curing resin cements is preferable to self-curing cements.
Crowns ; Dental Caries ; Fibrinogen ; Lactic Acid ; Mouth ; Prostheses and Implants ; Resin Cements* ; Resins, Synthetic ; Solubility* ; Water*

Recently as the esthetic concerns about dental prosthesis have been increased, the nonmetallic post and core systems have been introduced clinically to improve the color and the low optical transmittance of conventional casting metal post and core systems. The purpose of this study was to compare and analyze the optical transmittance and the shade changes of all-ceramic crowns with two nonmetallic post and core systems. The experimental groups were classified as follows: Total 27 specimens(9 samples in each group) were evaluated. Group I: Natural teeth as a control group. Group II: CosmoPost and Empress(R) core (Ivoclar-Vivadent, Liechtenstein). Group III: LIGHT-POST(TM) and LIGHT-CORE(TM)(Bisco, U.S.A.). In all groups, all-ceramic crowns were fabricated with the same shade of IPS Empress(R)II(Ivoclar-Vivadent, Liechtenstein) after abutment preparation, and then two kinds of spectrophotometers, UV 3101 PC(Shimadzu,Japan) and CM 503i(Minolta Co., Ltd., Japan), were used to measure the optical transmittance and the color value. The following results were obtained: 1. The optical transmittance of each group without all-ceramic crowns, was siginificantly decreased in order of Group III, I and II(p<0.05). 2. The optical transmittance of each group with all-ceramic crowns cemented, were siginificantly decreased in order of Group I, II and III(p<0.05). 3. In comparison with the shade of all-ceramic crowns, there were no significant differences between groups regardless of the cementation. 4. In comparison with the shade changes in each group after the cementation of all-ceramic crowns, there were no significant differences between groups. From the above results, it is thought that the selection among materials used in this study doesn't influence greatly the esthetic restoration, because the differences of optical transmittance were so small that those were clinically insignificant.
Cementation ; Crowns* ; Dental Prosthesis ; Tooth

As the inaccuracy which was made in implant impression prevented passive fit,it needed to solder the sectioned framework at several locations to correct the inaccuracy. Many clinicians have suggested impression techniques which could make passive fit between implant and superstructure. The purpose of this research was to measure and compare the accuracy of three methods of taking impression with the strain amplifier. The experimental groups were classified as follows : Group I; splinted the two parts with Futar D Occlusion. Group II; splinted the two parts with DuraLay. Group III; didn't splint the two parts. The results were as follows ; 1.The values of strain in the vertical and horizontal surfaces were increased in the order of groupI,group II and group III. 2.Group I showed higher accuracy of the duplicated casts in the vertical and horizontal surfaces than group IIand group III(p<0.05). 3.There were no significant differences in the accuracy of the duplicated casts between group IIand groupIII. From the above results,it is considered that the splinting method of impression copings could make an influence on the accuracy of the master casts.To improve the accuracy of the master casts, splinting the squared impression copings with the additional silicone occlusion materials is recommendable.
Silicones ; Splints