This study was performed to investigate the retrievability of the cementation type implant abutments. The cements used in this study were Cavitec, Tembond and Zine Phosphate Cement. The types of surface conditioning were no treatment, 50 microne sandblasting, 250 microne sandblasting, fine diamond finishing point and coarse diamond point. The retention of cast crown was measured with Instron University Testing Machine(Instron Engineering Co., U.S.A.) The results were as follows: 1. The Maximium retention was obtained by the group of Z.P.C. cementation and Coarse diamond point surface conditioning. 2. Z.P.C. shows maximum retention, and reduced in orders Tembond, Cavitec, No cement. 3. The value of retention of surface condition was highest in coarse diamond point, lowest in no tretment. 4. The similar results were obtained between fine diamond point and 50 microne sandblasting, coarse diamond point and 250 microne sandblasting. 5. The were no direct corelation between mechanical retetnion and cementation retention.
Cementation* ; Crowns ; Diamond

Recently radiation and radioisotope are being used widely in many fields such as medicine and industry. But only a few papers were reported about the radio dermatitis due to industrial use of radiation. Authors experienced 4 cases of occupational radiodermatitis due to Ir-192 occur red during the radioisotope traspierce test. All 4 patients noticed painful swelling, erythema, and bullae on their fingers or palms 1-2 weeks after exposure. All laboratory tests to detect ystemic effects of radiation were normal. Three patients recovered after treatment with systemic and topical corticosteroid and emollient cream for 2-4 weeks. But one patient suffered from complication of fibrosis and recurrent cellulitis on his fingers. We discussed about the working situation of our patients and reviewed the literatures about the radiodermatitis.
Cellulitis ; Dermatitis ; Erythema ; Fibrosis ; Fingers ; Humans ; Radiodermatitis

PURPOSE : The purpose of this study was to determine proper position and angulation of an implant for immediate implantation. MATERIALS AND METHOD : From the years 1997 to 2000, 52 Denta scanR views, 22 upper and 32 lower jaw with an average age of 43 and 40 respectively, were investigated, which comprise intact upper and lower 6 anterior teeth and premolars. on the Denta scanR, the optimal placement for the immediated implantation was simulated. The measuring methods included. 1) Angulation difference between tooth long axis and alveolar bone process. 2) Angulation difference of long axis between tooth and installing fixture 3) Distance between center of tooth at cervical area and center of fixture. 4) Distance from root apex to the bone limit of vital structure. One sample t-test was used for statistical analysis. RESULT : The results were as follows. 1) At the maxillary central incisor and lateral incisor, angulation difference of long axis between tooth and installing fixture was respectively 0.5 and 3.2degrees with the fixture center's palatally positioned 2mm apart from tooth center. 2) At the lower anterior 6 teeth, that was about -2.8degree to -4.6degree with the fixture center's lingually positioned 1mm apart from tooth center. 3) At the maxillary canine and premolar, that was respectively 11.8degree and 7.2degree with the fixture center palatally positioned 2~2.4mm apart from tooth center. 4) At the lower premolar area, that was about 0degree to 2degree with the fixture center's lingually positioned 0.5~1mm apart from tooth center. 5) Distance from root apex to the bone limit of vital structure, at the maxillary anterior and premolars, was the range of 10 to 12mm, and at the mandibular anterior teeth and the 1st premolar, that was the range of 18 to 20mm. CONCLUSION : The proper implant position of maxillary anterior and premolar teeth is as paralleled as or more buccally angulated than long axis of tooth with the fixture center's palatally positioned. in mandibular anterior region, long axis of implants is lingully angulated compared with compared with long axis of tooth and in premolar, almost parelleled with long axis of tooth and alveolar process.
Alveolar Process ; Axis, Cervical Vertebra ; Bicuspid ; Dental Implantation* ; Dental Implants* ; Incisor ; Jaw ; Statistics as Topic* ; Tooth

This investigation evaluated the fracture toughness (KIC) of eight currently available core materials, and relate the fracture toughness value to fractography analysis and surface characteristics using a atomic force microscope (AFM). Single-edge notched (SEN) test specimens (n=10) and compact tension (CT) test specimens (n=10) were prepared conforming to the ASTM Standard E-399 for a high copper amalgam, three composite core materials (Core-Max II, Core Paste, Bisfil Core), two reinforced composite core materials (Ti-Core, Ti-Core Natural), a resin-modified glass ionomer core material (Vitremer), and a conventional glass ionomer core material (Ketac-Molar). The specimens were tested with an Instron Universal Testing Machine. The maximum loads were measured to calculate the fracture toughness (KIC). Thereafter, fracture surfaces of SEN specimens of each material were investigated for fractography analysis using scanning electron microscope. And, disc-shaped specimens with 1mm thickness were fabricated for each material and were investigated under AFM for surface morphology analysis. The results were as follows : 1. Bisfil Core showed the highest mean fracture toughness regardless of test methods. 2. For the tooth-colored materials, Ti-Core Natural exhibited the highest fracture toughness. 3. Ketac Molar showed a significantly low fracture toughness when compared with the amalgam and the composite resin core materials (p<0.05). 4. The fracture toughness values obtained with the single-edge notched test, except Ketac Molar, were higher than those obtained in the compact tension test. 5. SEM revealed that the fracture surface of high fracture toughness material was rougher than that of low fracture toughness material. 6. AFM revealed that the surface particles of the composite resins were smaller in size, with a lower surface roughness than the glass ionomer core materials.
Composite Resins ; Copper ; Glass ; Molar

PURPOSE: The aim of this article is to analyze the preference for treatment modality of dentists. MATERIAL AND METHODS: Data of 20,038 patients was involved. Data analysis were done by distribution according to the various kinds of prosthesis, including complete denture, removable partial denture, fixed partial denture, implant-supported dental prosthesis as well as distribution according to the professional titles of the dentists finishing the treatment, including resident and professors. RESULTS: The number of cases of dental prosthesis increased year by year. 61.06% of the patients accepted fixed partial denture restoration. The number of patients who accepted implant supported restoration is also increasing year by year. The number of complete denture, implant-supported dental prosthesis finished by professors was larger than that done by residents, while it was contrary for removable partial denture, fixed partial denture, and the difference was statistically significant (P<.05). CONCLUSION: Professors and residents have some difference in the categorization of prosthesis finished. Fixed partial denture and implant-supported dental prosthesis are preferred.
Dental Prosthesis ; Dental Prosthesis, Implant-Supported ; Dentists ; Denture, Complete ; Denture, Partial, Fixed ; Denture, Partial, Removable ; Humans ; Prostheses and Implants ; Prosthodontics ; Statistics as Topic

We present here, a case of pemphigus erythematosus developed in a 31-year-old woman, who had been suffering from repeated episode, of remission and exacerbation with several erythematous, and somewhat oozing patche accompanying a mild pruritus or her face, upper part of the back and anterior chest. In serological studies, she had antinuclear antiboc@lies at. a titer of 1:160. Histopathological finding showed subcorneal bullae. Immunofluorescent study revealed IgG and C, deposition in the intercellular space of the epidermis and along the de rmoepidermal junction.
Adult ; Epidermis ; Extracellular Space ; Female ; Fluorescent Antibody Technique ; Humans ; Immunoglobulin G ; Pemphigus* ; Pruritus ; Thorax

STATEMENT OF PROBLEM: Currently, there are some 20 different geometric variations in implant/abutment interface available. The geometry is important because it is one of the primary determinants of joint strength, joint stability, locational and rotational stability. PURPOSE: As the effects of the various implant-abutment connections and the prosthesis height variation on stress distribution are not yet examined, this study is to focus on the different types of implant-abutment connection and the prosthesis height using three dimensional finite element analysis. MATERIAL AND METHOD: The models were constructed with ITI, 3i TG, Bicon, Frialit-2 fixtures and solid abutment, TG post, Bicon post, EstheticBase abutment respectively. And the superstructures were constructed as mandibular second premolar shapes with 8.5 mm, 11 mm, 13.5 mm of crown height. In each model, 244 N of vertical load and 244 N of 30 degree oblique load were placed on the central pit of an occlusal surface. von Mises stresses were recorded and compared in the crowns, abutments, fixtures. RESULTS: 1. Under the oblique loading, von Mises stresses were larger in the crown, abutment, fixture compared to the vertical loading condition. 2. The stresses were increased proportionally to the crown height under oblique loading but showed little differences with three different crown heights under vertical loading. 3. In the crown, the highest stress areas were loading points under vertical loading, and the finish lines under oblique loading. 4. Under the oblique loading, the higher stresses were located in the fixture/abutment interface of the Bicon and Frialit-2 systems compared to the ITI and TG systems. CONCLUSIONS: The stress distribution patterns of each implant-abutment system had difference among them and adequate crown height/implant ratio was important to reduce the stresses around the implants.
Bicuspid ; Crowns ; Finite Element Analysis* ; Joints ; Prostheses and Implants

STATEMENT OF PROBLEM: Currently, there are some 20 different geometric variations in implant/abutment interface available. The geometry is important because it is one of the primary determinants of joint strength, joint stability, locational and rotational stability. PURPOSE: As the effects of the various implant-abutment connections and the prosthesis height variation on stress distribution are not yet examined, this study is to focus on the different types of implant-abutment connection and the prosthesis height using three dimensional finite element analysis. MATERIAL AND METHOD: The models were constructed with ITI, 3i TG, Bicon, Frialit-2 fixtures and solid abutment, TG post, Bicon post, EstheticBase abutment respectively. And the superstructures were constructed as mandibular second premolar shapes with 8.5 mm, 11 mm, 13.5 mm of crown height. In each model, 244 N of vertical load and 244 N of 30 degree oblique load were placed on the central pit of an occlusal surface. von Mises stresses were recorded and compared in the crowns, abutments, fixtures. RESULTS: 1. Under the oblique loading, von Mises stresses were larger in the crown, abutment, fixture compared to the vertical loading condition. 2. The stresses were increased proportionally to the crown height under oblique loading but showed little differences with three different crown heights under vertical loading. 3. In the crown, the highest stress areas were loading points under vertical loading, and the finish lines under oblique loading. 4. Under the oblique loading, the higher stresses were located in the fixture/abutment interface of the Bicon and Frialit-2 systems compared to the ITI and TG systems. CONCLUSIONS: The stress distribution patterns of each implant-abutment system had difference among them and adequate crown height/implant ratio was important to reduce the stresses around the implants.
Bicuspid ; Crowns ; Finite Element Analysis* ; Joints ; Prostheses and Implants

PURPOSE: The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. MATERIAL AND METHODS: One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (the empty set 4 mm x 6 mm) were fabricated and randomly divided into two groups (Group I: Immediately, Group II: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe test and independent sample t test (alpha = 0.05). RESULTS: Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. CONCLUSION: The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.
Acrylic Resins ; Bisphenol A-Glycidyl Methacrylate ; Collodion ; Composite Resins ; Crowns ; Denture, Partial, Fixed ; Methacrylates ; Polymethacrylic Acids ; Tensile Strength

STATEMENT OF PROBLEM: Recently Yttrium-stabilized tetragonal zirconia polycrystal (Y-TZP) has been introduced due to superior flexural strength and fracture toughness compared to other dental ceramic systems. Although zirconia has outstanding mechanical properties, the phenomenon of decrease in the life-time of zirconia resulted from degradation in flexural strength after low temperature aging has been reported. PURPOSE: The objective of this study was to investigate degradation of flexural strength of Y-TZP ceramics after various low temperature aging treatments and to evaluate the phase stability and micro-structural change after aging by using X-ray diffraction analysis and a scanning electron microscope (SEM). MATERIAL AND METHODS: Y-TZP blocks of Vita In-Ceram YZ (Vita Zahnfabrik, Bad Sackingen, Germany) were prepared in 40 mm (length) x 4 mm (width) x 3 mm (height) samples. Specimens were artificially aged in distilled water by heat-treatment at a temperature of 75, 100, 125, 150, 175, 200, and 225degrees C for 10 hours, in order to induce the phase transformation at the surface. To measure the mechanical property, the specimens were subjected to a four-point bending test using a universal testing machine (Instron model 3365; Instron, Canton, Mass, USA). In addition, X-ray diffraction analysis (DMAX 2500; Rigaku, Tokyo, Japan) and SEM (Hitachi s4700; Jeol Ltd, Tokyo, Japan) were performed to estimate the phase transformation. The statistical analysis was done using SAS 9.1.3 (SAS institute, USA). The flexural strength data of the experimental groups were analyzed by one-way analysis of variance and to detect statistically significant differences (alpha= .05). RESULTS: The mean flexural strength of sintered Vita In-Ceram YZ without autoclaving was 798 MPa. When applied aging temperature at below 125degrees C for 10 hours, the flexural strength of Vita In-Ceram YZ increased up to 1,161 MPa. However, at above 150degrees C, the flexural strength started to decrease. Although low temperature aging caused the tetragonal-to-monoclinic phase transformation related to temperature, the minimum flexural strength was above 700 MPa. CONCLUSION: The monoclinic phase started to appear after aging treatment above 100degrees C. With the higher aging temperature, the fraction of monoclinic phase increased. The ratio of monoclinic/tetragonal + monoclinic phase reached a plateau value, circa 75% above 175degrees C. The point of monoclinic concentration at which the flexural strength begins to decrease was between 12% and 54%.
Aged ; Aging ; Aluminum Oxide ; Ceramics ; Collodion ; Dental Porcelain ; Electrons ; Humans ; Phenothiazines ; Tokyo ; Water ; X-Ray Diffraction ; Yttrium ; Zirconium