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The effect of tooth brushing and thermal cycling on a luster change of ceromers finished with different methods.

The Journal of Korean Academy of Prosthodontics.2000;38(3):336-347.

STATEMENT of PROBLEM: Luster loss in esthetic anterior ceromer restoration can occur and can be related with rough surface texture. Understanding durability of surface finishing methods like polishing and surface coating have critical importance. PURPOSE: This study evaluated the effect of tooth brushing and thermal cycling on surface luster of 3 ceromer systems (Artglass, Targis, Sculpture) treated with different surface finishing methods. MATERIAL AND METHODS: Seventy-two samples were prepared: 12 for control group Z100, 12 for Artglass, 24 for Targis, and 24 for Sculpture. Half of the Targis and Sculpture were polished according to the manufacturer's recommendation. The rest of the samples were coated with staining and glazing solution for Targis and Sculpture, respectively. All specimens were subjected to 10,000 cycles between 5 degreesC and 55 degreesC with 30 seconds dwell time. Tooth brushing abrasion tests were performed in a customized tooth brushing machine with 500g backand forth for 20,000 cycle. Luster comparisons were based on grading after direct observation, and light reflection area was measured with Image analysis software. RESULTS: All materials showed an decrease in luster grade after thermal cycling and tooth brushing. The post-tooth brushing results revealed that the glazed Sculpture had greater mean luster grade than did any other groups. While, the stained Targis group showed greatest changes after tooth brushing (p>0.05), polished Targis and Sculpture did not show significant changes. However, glazed Sculpture showed discretely fallen out glaze resin. CONCLUSION: From the results of this study, all of the ceromer specimens were much glossy than control composite group after tooth brushing. coatings used for Targis and Sculpture had not durability for long term use.
Sculpture ; Tooth*

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A qualitative analysis of bonding between electroformed surface and veneering ceramics.

Ho Beom KWON ; Soon Ho YIM

The Journal of Korean Academy of Prosthodontics.2000;38(3):328-335.

STATEMENT of THE PROBLEM: Recently an innovative method of fabricating indirect restorations by gold electroforming has been developed. But the bond quality and strength of the gold coping to the porcelain is uncertain. PURPOSE of STUDY: The purpose of this study is to analyze and evaluate the electroformed gold surface for mechanical bonding between the gold and the ceramic veneering. METHODS and MATERIAL: Electroformed disks were made using electroforming technique. And the surface of the electroformed coping was analyzed after sandblasting, heat-treatment, bonding agent application, opaque porcelain firing with scanning electron microscopy and energy dispersive x-ray analysis. Results. In the analysis with SEM, Sandblasting made the sharp edges and undercuts on the electroformed surface, and after bonding agent application, net-like structure were created on the electroformed surface. In the energy dispersive x-ray analysis it is confirmed that electroformed surface contains some impurities. CONCLUSION: With the use of sandblasting and bonding agent, electroformed surface seems to be enough to bond with veneering porcelain.
Ceramics* ; Dental Porcelain ; Fires ; Microscopy, Electron, Scanning

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Anatomical Site Classification for Implant Insertion: ASCII.

Seung Mi JEONG ; Chae Heon CHUNG ; W ENGELKE

The Journal of Korean Academy of Prosthodontics.2000;38(3):321-327.

STATEMENT of PROBLEM: As a standard means of diagnostics, an orthopantomogram(OPT) permits to measure the vertical and mesiodistal dimension of available bone at the desired implant site with the help of suitable radioopaque references. Based on the clinical investigation of the dentition and the edentulous sites, information upon the width of the implant site can be obtained and documented in the dental scheme. Both findings permit together systematic primary planning for endosteal implants. PURPOSE of STUDY: Contents of the present article are the representation of a semiquantitative classification of available bone with the aim to simplify the primary phase of a systematic implant planning. RESULTS: Thus the ASCII-system permits a clear protocol of bone findings for the implant case with all information available during the primary appointment for treatment planning as a basis of further diagnostic and therapeutic measures. CONCLUSION: With the ASCII system, important parameters such as alveolar height and subcrestal alveolar width can be documented systematically, easily and time saving in the dental scheme as a basis for exact treatment planning.
Classification* ; Dentition

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A Study on the Accuracy of the record base of the Complete Denture to the Master Cast according to Kinds of Resin and Polymerization Method.

Hyo Jin CHOI ; Ju Hwan LIM ; In Ho JO

The Journal of Korean Academy of Prosthodontics.2000;38(3):310-320.

STATEMENT of THE PROBLEM: The record base in fabricating procedures of the complete denture, as a temporary form for reproducing denture base, is used to record upper and lower jaw relation and to align artificial teeth and try-in it in the mouth. The accuracy of jaw relation record is affected by the accuracy, stiffness and stability of the record base. So, the accuracy of record base is the most important requirements of jaw relation records. PURPOSE of STUDY: The purpose of this study was to evaluate the gap that occurred over the palatal area of a maxillary record base fabricated with autopolymerizing resin and light-curingresin. METHODS AND MATERIAL: The maxillary record bases were fabricated out of autopolymerizing resin that is used the most frequently in clinics and light-curing resin that attracts special attentionfor its several merits. The light-curing resin was made by two kinds of polymerization methods, which are one step curing method and multiple step curing method. All record bases were cut in certain positions of the master cast 1 hour and 1 day later after fabrication and the accuracy of the master cast was measured and analyzed with a microscope. RESULTS: A pattern of gap formation between the record base and the maxillary cast was observed in all specimens. According to kinds of resins, autopolymerizing resin was significantly more accurate than light-curing resin. There was no statistical difference according to time lapse, and in all three groups, the maximum discrepancy occurred at the posterior border in the midpalatal region. CONCLUSLON: The autopolymerizing resin is better than light-curing resin, and multiple step curing method is more accurate than one step curing method when using light-curing resin.
Denture Bases ; Denture, Complete* ; Jaw ; Jaw Relation Record ; Mouth ; Polymerization* ; Polymers* ; Tooth, Artificial

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Radiation effect on peri-implant tissue after implantation.

Hyeong Sin KWEON ; Kwang Yeob SONG

The Journal of Korean Academy of Prosthodontics.2000;38(3):291-309.

STATEMENT of PROBLEM: There were several studies on the effects of irradiation to periimplant bone tissue. However, no clear biological effect of irradiation on peri-implant bone tissue was reported yet. PURPOSE: This study compared the effect of irradiation on the surrounding tissue of a HA-coated implant fixture with controls. MATERIAL AND METHODS: 6 Steri-Oss implants were implanted into the femur of 6 mongrels. The implanted dogs were divided into three groups and received irradiation. After 1 month, 2months and 4 months healing period, the histologic examination and mobility test and digital radiographic imaging analyses were performed to compare the control and experimental group respectively. RESULTS: The irradiated group showed slower healing than control group in light microscopic observations. The mobility test demonstrated significant less number (Periotest) in control group than that of irradiated groups. The digital radiographic imaging analysis showed that the bone density of irradiated group was higher than control group. CONCLUSION: Generally, control group showed favorable bilogical response and less mobility than irradiated group. The conflict result of bone density value were measured by the dig-.
Animals ; Bone and Bones ; Bone Density ; Dogs ; Femur ; Radiation Effects*

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Stress analysis of anterior cantilever bridge.

Hong So YANG ; Chul Whoi KU

The Journal of Korean Academy of Prosthodontics.2000;38(3):283-290.

STATE MENT of PROBLEMS: Although some clinicians report long-term success with fixed partial denture (FPD) that contain cantilever pontic, the use of cantilever FPDs may be hazardous because of unfavorable leverages during mastication. PURPOSE of STUDY: This study aims to compare the stress induced in the periodontium with normal and reduced bone support, and to analyze the stress distribution patterns of anterior cantilevered FPDs using the finite element method. RESULTS: Cantilever bridge with a reduced bone level generated the highest peak stresses in the periodontium. In the models of reduced bone support, a cantilever bridge exhibited the greatest mobility and a 3-unit fixed restorations induced the smallest mobility of canine. The highest peak stress level of a 3-unit bridge in the periodontium is similar to the unrestored situation. But stress distribution in the bone is modified. CONCLUSION: In reduced bone support, a cantilever bridge exhibited the greatest mobility and stress.
Denture, Partial, Fixed ; Mastication ; Periodontium

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