evaluation of artificial teeth color using

EVALUATION OF ARTIFICIAL TEETH COLOR USING SPECTROPHOTOMETER Mohamed Ahmed Alkhodary*, **

ABSTRACT Introduction: Artificial teeth used for removable prostheses frequently do not harmonize with the color of natural teeth in partial denture wearers, leading to unpleasant esthetics. Accordingly, the aim of this study was to evaluate the validity of artificial teeth color, as supplied by the manufacturer, using a clinical spectrophotometer. Materials and methods: The VITA Easyshade Advance clinical spectrophotometer was used in the comparison mode to evaluate the color of 6 randomly selected artificial teeth sets (Vivodent Orthotype DCL by Ivoclar vivadent: A1, A2, A3, B3, C2, and D3). Results were analyzed using IBM SPSS software package version 20.0. Results: The results indicated that the color of the selected shades did not vary from those standard colors set in the device manufactured by a different company. Conclusion: Within the limitations of the present study, the coefficient of variation, of artificial teeth colors from standard color dimensions set in the clinical spectrophotometer, was not high, and such teeth colors are clinically acceptable and reliable. KEYWORDS: Artificial teeth color, Spectrophotometer, Coefficient of variation

INTRODUCTION

by a visual technique, the color considered is

The human dentition shades vary considerably and there can be about one hundred thousand dental shades distinguished using modern electronic instruments, while human eye can recognize only 1 percent of the shades. Color can be described according to the Munsell color space in terms of hue, value and chroma. When the color is measured

compared with a large set of color tabs. Value is determined first, and chroma is determined next with tabs that are close to the measured value but are of increasing saturation of color. Hue is determined last by matching with color tabs of the value and chroma already determined. (1-4) In 1976, the Commission Internationale de l’Eclairage (CIE)

* Lecturer of Removable Prosthodontics, Faculty of Dentistry, Alexandria University ** Assistant Professor, Department of Prosthetic Dental Science, College of Dentistry, Qassim University, KSA.

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refined the color space; CIE L value is a measure of the lightness of an object, CIE a value is a measure of redness or greenness, and CIE b value is a measure of yellowness or blueness and their delta (ΔE) equals [ (ΔL)2 + (Δa)2 + (Δb)2]1/2. The measurements of tooth color using instrumental techniques include spectrophotometry, colourimetry and computer analysis of digital images. Due to inter-human differences in the perception of color, visual shade assessment of teeth is lacking standardization that may be improved by the use of a spectrophotometer. (6-10) Spectrophotometric shade analysis of natural teeth was more accurate and more reproducible compared with human shade assessment (83.3% compared to 26.6%). However, the instrument is designed to measure flat surfaces, and small aperture colorimeter is prone to significant edge-loss effects. With the evolution of optic fiber technology, dental manufacturers are now able to produce cost-effective spectrophotometers that are easy to operate, with a large aperture for measurement.(11-15) In contrast to the single crowns and fixed bridges which are custom made to suite the shape and color of individual patients’ teeth (16-18) , artificial teeth used for removable prostheses are usually used in their readymade state, rarely specified, and frequently their color do not harmonize with the color of natural teeth in partial denture wearers, leading to unpleasant esthetics. Accordingly, the aim of this study was to evaluate the validity of artificial teeth color, as supplied by the manufacturer, using a clinical spectrophotometer.

Mohamed Ahmed Alkhodary

MATERIALS AND METHODS The VITA Easyshade Advance clinical spectrophotometer (Fig.1) was used in this study to evaluate the color of 6 randomly selected artificial teeth sets (Vivodent Orthotype DCL by Ivoclar vivadent: A1, A2, A3, B3, C2, and D3). (Fig.2) The comparison mode in the Vita Easy shade Advance was selected, and then comparison was made to each of the selected shades (Fig.3a-d). The device was calibrated before each reading by pressing the hand piece tip against the standard platform according to the manufacturer’s recommendations. Then the color evaluation was repeated 3 times for each tooth (Fig.3c), and average reading was registered. A light grey background was used during the procedures. For statistical analysis of the data, results were fed to the computer and analyzed using IBM SPSS software package version 20.0. (19, 20) The coefficient of variation (CV) was computed. The CV expressed as a percentage (%), was calculated as the square root of the variance divided by the mean. Significance of the obtained results was judged at the 5% level.

FIG.

(1) The VITA spectrophotometer

Easyshade

Advance

clinical

EVALUATION OF ARTIFICIAL TEETH COLOR USING SPECTROPHOTOMETER

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Fig. (2) Artificial teeth sets (Vivodent Orthotype DCL by Ivoclar vivadent: A1, A2, A3, B3, C2, and D3).

Fig. 3: (a) the comparison mode was selected, (b) the shade to which comparison to be made was selected, (c) the tooth shade is measured using the VITA Easyshade Advance, (d) the differences from the standard color set in step (B) were displayed on the LCD screen on the bottom of the device hand piece in the form of ΔE, lightness (L), chroma (C), and Hue (h).

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value of ΔE was 2.22 (ΔE