OBJECTIVETo compare the color character of VITA shade guide and the custom shade guide with metal substrate.

METHODSColor of 9 sites of 5 series of VITA shade guides and custom shade guides with metal substrate were measured by means of PR-650 spectrophotometer.

RESULTSThe color range of VITA shade guide were that L* was 56.86-73.86, a* was-1.29-3.69, b* was 7.09-21.94, and the transparence was 3.20-7.59. The color range of the custom shade guide was that L* was 60.59-78.54, a* was -1.09-4.99, b* was 7.60-22.35, and the transparence was 0.23-10.98. L*, a* and b* of the custom shade guide with metal substrate were higher than VITA shade guide, and the transparence was differet. The color difference of homonymy shade tab between custom shade guide and VITA shade guide was larger than 1.5 NBS.

CONCLUSIONThere is color difference between VITA shade guide and custom shade guide. Metal substrate has effects on the color of cero-metal prosthesis, and color selection in clinic should be carefully considered.

Color ; Dental Prosthesis Design ; Prosthesis Coloring ; Spectrophotometry

OBJECTIVE: This study aimed to compare the effect of D55 and D65 light sources on the visual colorimetry performance of dental students by using a homemade light-source shelf. METHODS: Two Vitapan 3D-Master shade guides were randomly selected. One set was used as shade guides. Ten commonly used shade tabs of 2L2.5, 2M2, 2R2.5, 3M2, 3R2.5, 3L1.5, 3R1.5, 3L2.5, 4R1.5, and 4L1.5 were selected from the other set with covered value marks and numbered from 1 to 10. After the colorimetric training, 49 undergraduate dental students were randomly divided into two groups. Each student randomly selected two of the 10 shade tabs, and the colors were subsequently matched under D65 and D55 light sources from a distance of approximately 40 cm. The average color difference (ΔE) between the color selected by each participant and the actual color of shade tabs was calculated. Paired t test was used for statistical analysis. RESULTS: The ΔE values between the color selected by each participant and the actual color of the shade tabs under the D55 light source varied from 0 to 6.540. The average value was 2.501. The ΔE values between the color selected by each participant and the actual color of the shade tabs under the D65 light source varied from 0 to 6.610. The average value was 2.530. No statistically significant difference was observed between the results under the two light sources (P=0.921). CONCLUSIONS Both D55 and D65 daylight lamps can be used for daily dental colorimetry. These two different color temperatures showed no significant difference.
Color ; Colorimetry ; Dental Prosthesis Design ; Humans ; Prosthesis Coloring ; Students, Dental

OBJECTIVETo investigate the color difference between Au-Pt alloy porcelain and Ni-Cr alloy porcelain.

METHODS30 metal-ceramic specimens with different dentin porcelain thickness were fabricated with two types of metal-ceramic alloy, each type of alloy had 15 specimens. L*, a*, b* were measured after opaque porcelain was applied, and dentin porcelain was fired 1, 3, 5, 7 times by MINOLTA CR-100. Then delta E was calculated which reflected the color difference between high-gold alloy porcelain and Ni-Cr alloy porcelain.

RESULTSComparing with Ni-Cr alloy porcelain, the color of Au-Pt alloy porcelain was reddish, yellowish and less bright. The delta E between high-gold alloy porcelain and Ni-Cr alloy porcelain in shade A2 was largest when opaque porcelain was applied. It decreased when dentin porcelain was applied. It became smallest when fired 3 times, and increased along with the increase of fire times. It was larger than 1.5 except firing 3 times. When dentin porcelain was applied, delta E which was larger than 1.5 among different dentin porcelain thickness decreased along with the increase of dentin porcelain thickness.

CONCLUSIONThe color difference between the two types of metal-ceramic alloy should be carefully taken into account in order to improve the quality of color matching.

Chromium ; Chromium Alloys ; Dental Porcelain ; Dental Prosthesis Design ; Gold Alloys ; Humans ; Metal Ceramic Alloys ; Nickel ; Platinum ; Prosthesis Coloring

OBJECTIVETo determine the infinite optical thickness of dentine porcelain of IPS E.max A color series.

METHODSCylindrical dentine porcelain specimens of the IPS E.max A color series were prepared with a diameter of 13 mm and thickness of 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 mm. The chromatic value of all the specimens was determined with CM-5 spectrometer against standard black and white background. The chromatic aberration (deltaE) was calculated by regression equation.

RESULTSThe infinite optical thickness of dentine porcelain of the IPS E.max A color series ranged from 2.341 to 3.333 mm for a deltaE of 1.0, and from 2.064 to 2.904 mm for a deltaE of 1.5. As the chromaticity or thickness increased, the influence by the background color decreased, and the color of specimens became gradually close to the intrinsic color.

CONCLUSIONThe thickness of the background dentine porcelain specimens must exceed its infinite optical thickness to represent the intrinsic color and avoid the influence by the extrinsic color.

Coated Materials, Biocompatible ; chemistry ; Crowns ; Dental Porcelain ; chemistry ; Dental Prosthesis Design ; Humans ; Prosthesis Coloring ; Tooth Preparation, Prosthodontic ; methods

OBJECTIVEThe purpose of this study was to evaluate the color masking ability of Computer Aided Design/Computer Aided Manufacture(CAD/CAM) machining ceramic Vita Mark II, this ability was affected by thickness and shade.

METHODSEach of 5 specimens of 0.5 mm, 1.0 mm and 1.5 mm Vita Mark II A3C/18 and A2C/18 were prepared and the color change was measured after the substrate simulating stained teeth was covered with the specimen.

RESULTSStatistically significant differences (P < 0.01) were recorded in the substrates covered with different thickness and shade of Vita Mark II. The color changes (delta E) were 15.181, 17.691, 19.667 and 15.653, 16.880, 18.002 after the substrates were covered with 0.5 mm, 1.0 mm and 1.5 mm Vita Mark II A3C/18 and A2C/18.

CONCLUSIONAs a dental material, CAD/CAM Vita Mark II has high quality to mask the underlying color. Being a veneer, the masking ability with A2C/18 is better than that with A3C/18, but being an inlay, the result is reverse.

Color ; Colorimetry ; Crowns ; Dental Porcelain ; Dental Prosthesis Design ; Denture, Partial, Fixed ; Humans ; Metal Ceramic Alloys ; Prosthesis Coloring ; standards

This paper introduces the current development and challenges of vision prosthesis.
Prosthesis Design ; Visual Prosthesis

OBJECTIVETo study the effect of repeated firings on color of porcelain-fused-to-titanium restorations.

METHODSTwenty standard porcelain-fused-to-titanium specimens were made with Dentsply DETREY TiBond C3 and Dentaurum rematitan Til. Then they were fired 1, 2, 4, 7, and 10 times. Color measurement was done after each firing.

RESULTMost of the color parameters had no significant difference after firing except for a* and Hab. All the color difference among groups were smaller than 1.0 (deltaE < 1.0).

CONCLUSIONRepeated firings will not affect the color stability of porcelain-fused-to-titanium restorations.

Color ; standards ; Dental Porcelain ; Denture Design ; Humans ; Metal Ceramic Alloys ; Prosthesis Coloring ; methods ; Titanium

This review paper presents the current research progress, challenges and future development on microelectrode array of retinal prosthesis, including epi-retinal and sub-retinal implants.
Microelectrodes ; Prosthesis Design ; Visual Prosthesis

OBJECTIVEEstablish the test platform of the intraocular lens loop, and the platform was evaluated through the experiment.

METHODSThe intraocular lens loop test platform is made up with three models. The different intraocular lens haptics support force can be completed by replacing different sample holder model.

RESULTSThe standard deviation and the coefficient of variation were calculated through the result of the fifteen samples. The standard deviation was 0.04 mN, and the coefficient of variation was 0.66%. The two values were in the acceptable range.

CONCLUSIONSThe platform was so stabilizing that it could be used to test support force of IOL loop. The different shapes of IOL could be tested on the platform through the replacement of the holder model.

Lenses, Intraocular ; Prosthesis Design

In this paper, the present research status of artificial cervical disc is summarized according to its configuration, material selection and the methodologies of design. Finally, the further progress of research on artificial cervical disc is prospected as well.
Intervertebral Disc ; Joint Prosthesis ; Prosthesis Design