1.ANALYSIS OF PORCELAIN SURFACE ROUGHNESS POLISHED BY VARIOUS TECHNIQUE.
Kyu Young LEE ; Chung Hee LEE ; Kwang Hun JO
The Journal of Korean Academy of Prosthodontics 1998;36(3):506-513
This study was designed to compare the smoothness by glazing method with that by polishing method after 48 specimens of Ceramco II block, one of porcelain materials used for PFM, were baked according to the manufacturer's directions. The specimens were roughened with new green stone at 15,000rpm for 30 seconds and sandblasted with 25microliteraluminum oxide for 15 seconds. They were divided into 4 groups at random, and 4 groups were prepared as follows : Group I : specimens were autoglazed and overpolished with polishing system. Group II specimens were polished with only polishing system. Group IIIspecimens were glazed after adding glazing liquid, vitachrom "L"-fluid (vita zahnfabrik co. Germany) to the rough surface Group v : specimens were just autoglazed Using the surface roughness tester, Ra, Rmax, and Rz were estimated 5 times per specimen, and recording process of mean value was repeated 3 times. The results were as follows : 1. The Ra of group I and group IIwas lower than group IIIand group IV (p<001). 2. There was lower value of Rz in group I and group II than group III and group IV (p<001). 3. The Rmax of group I(overpolished with polishing system after autoglazing) and group II(polished with only polishing system) was lower than group III(glazed after adding glazing liquid) and group IV (autoglazed) (p<001). 4. There was not a statistically significant difference between group I and II and between group III and IV (p>001). 5. The roughness was increase in order of group I,II,III,IV in SEM
Dental Porcelain*
2.The shear bond strength between dicor and several veneering porcelains.
Kyung Hee RYOO ; Sun Hyung LEE
The Journal of Korean Academy of Prosthodontics 1993;31(2):165-179
No abstract available.
Dental Porcelain*
3.Effect of surface treatment of porcelain on tensile bond strength.
Korean Journal of Orthodontics 1996;26(3):301-307
The purpose, of this study was to evaluate the effect of surface treatment of porcelain on tensile bond strength. To accomplish this purpose, this study was carried out with 120 samples which were divided into 12 groups with each 10 samples, and the first group was not surface treated, groups 2 through 5 underwent single surface treatment, and groups 6 through 12 underwent compound surface treatment. The results were as follows: 1. In statistic, all the single surface-treated groups showed higher tensile bond strength than the non surface-treated group and the sandblasted group showed the highest tensile bond strength as 10.34+/-2.50MPa. 2. All the compound surface-treated groups showed no noticeable difference in the tensile bond strength(9-11.5MPa). 3. In statistic, no significant difference was found between the sandblasted group and the compound surface-treated groups. 4. There was no fracture of porcelain while testing in this study. Above study demonstrated that compound surface treatment or sandblasing, if used single surface treatment, should be employed to guarantee successful clinical application.
Dental Porcelain*
4.A study on the bond strength between reused dental alloys and porcelain.
The Journal of Korean Academy of Prosthodontics 1993;31(2):181-190
No abstract available.
Dental Alloys*
;
Dental Porcelain*
5.Effect of surface treatment on bond strength of porcelain laminate veneer to enamel.
Yong Seok BAN ; Hyun Gon CHUNG ; Soon Ho HONG
The Journal of Korean Academy of Prosthodontics 1991;29(1):255-264
No abstract available.
Dental Enamel*
;
Dental Porcelain*
6.Proposal of new dental color-space for aesthetic dental materials.
Yun Jeong OH ; Su Jung PARK ; Dong Jun KIM ; Hyun Gu CHO ; Yun Chan HWANG ; Won Mann OH ; In Nam HWANG
Journal of Korean Academy of Conservative Dentistry 2007;32(1):19-27
The purpose of this study is to develope new dental color-space system. Twelve kinds of dental composites and one kind of dental porcelain were used in this study. Disk samples (15 mm in diameter, 4 mm in thickness) of used materials were made and sample's CIE L*a*b* value was measured by Spectrocolorimeter (MiniScan XE plus, Model 4000S, diffuse/8degrees viewing mode, 14.3 mm Port diameters, Hunter Lab. USA). The range of measured color distribution was analyzed. All the data were applied in the form of T### which is expression unit in CNU Cons Dental Color Chart. The value of L* lies between 80.40 and 52.70. The value of a* are between 10.60 and 3.60 and b* are between 28.40 and 2.21. The average value of L* is 67.40, and median value is 67.30. The value of a* are 2.89 and 2.91 respectively. And for the b*, 14.30 and 13.90 were obtained. The data were converted to T### that is the unit count system in CNU-Cons Dental Color Chart. The value of L* is converted in the first digit of the numbering system. Each unit is 2.0 measured values. The second digit is the value of a* and is converted new number by 1.0 measured value. For the third digit b* is replaced and it is 2.0 measured unit apart. T555 was set to the value of L* ranging from 66.0 to 68.0, value of a* ranging from 3 to 4 and b* value ranging from 14 to 16.
Dental Materials*
;
Dental Porcelain
8.Shear bond strength of porcelain repair resins to nonprecious ceramo-metal alloy.
Joon Young ANN ; Jung Soo BAE ; Dong Hoo HAN
The Journal of Korean Academy of Prosthodontics 1991;29(2):195-209
No abstract available.
Alloys*
;
Dental Porcelain*
9.The effect of various veneering techniques on the marginal fit of zirconia copings.
Kianoosh TORABI ; Mahroo VOJDANI ; Rashin GITI ; Masumeh TAGHVA ; Soheil PARDIS
The Journal of Advanced Prosthodontics 2015;7(3):233-239
PURPOSE: This study aimed to evaluate the fit of zirconia ceramics before and after veneering, using 3 different veneering processes (layering, press-over, and CAD-on techniques). MATERIALS AND METHODS: Thirty standardized zirconia CAD/CAM frameworks were constructed and divided into three groups of 10 each. The first group was veneered using the traditional layering technique. Press-over and CAD-on techniques were used to veneer second and third groups. The marginal gap of specimens was measured before and after veneering process at 18 sites on the master die using a digital microscope. Paired t-test was used to evaluate mean marginal gap changes. One-way ANOVA and post hoc tests were also employed for comparison among 3 groups (alpha=.05). RESULTS: Marginal gap of 3 groups was increased after porcelain veneering. The mean marginal gap values after veneering in the layering group (63.06 microm) was higher than press-over (50.64 microm) and CAD-on (51.50 microm) veneered groups (P<.001). CONCLUSION: Three veneering methods altered the marginal fit of zirconia copings. Conventional layering technique increased the marginal gap of zirconia framework more than pressing and CAD-on techniques. All ceramic crowns made through three different veneering methods revealed clinically acceptable marginal fit.
Ceramics
;
Crowns
;
Dental Porcelain
10.The effect of the amount of interdental spacing on the stress distribution in maxillary central incisors restored with porcelain laminate veneer and composite resin: A 3D-finite element analysis.
Junbae HONG ; Seung Min TAK ; Seung Ho BAEK ; Byeong Hoon CHO
Journal of Korean Academy of Conservative Dentistry 2010;35(1):30-39
This study evaluated the influence of the type of restoration and the amount of interdental spacing on the stress distribution in maxillary central incisors restored by means of porcelain laminate veneers and direct composite resin restorations. Three-dimensional finite element models were fabricated to represent different types of restorations. Four clinical situations were considered. Type I, closing diastema using composite resin. Labial border of composite resin was extended just enough to cover the interdental space; Type II, closing diastema using composite resin without reduction of labial surface. Labial border of composite resin was extended distally to cover the half of the total labial surface; Type III, closing diastema using composite resin with reduction of labial surface. Labial border of the preparation and restored composite resin was extended distally two-thirds of the total labial surface; Type IV, closing diastema using porcelain laminate veneer with a feathered-edge preparation technique. Four different interdental spaces (1.0, 2.0, 3.0, 4.0 mm) were applied for each type of restorations. For all types of restoration, adding the width of free extension of the porcelain laminate veneer and composite resin increased the stress occurred at the bonding layer. The maximum stress values observed at the bonding layer of Type IV were higher than that of Type I, II and III. However, the increasing rate of maximum stress value of Type IV was lower than that of Type I, II and III.
Dental Porcelain
;
Diastema
;
Incisor