Reproducibility of electronic tooth colour measurements.

Clinical methods of investigation, such as tooth colour determination, should be simple, quick and reproducible. The determination of tooth colours usually relies upon manual comparison of a patient's tooth colour with a colour ring. After some days, however, measurement results frequently lack unequivocal reproducibility. This study aimed to examine an electronic method for reliable colour measurement. The colours of the teeth 14 to 24 were determined by three different examiners in 10 subjects using the colour measuring device Shade Inspector. In total, 12 measurements per tooth were taken. Two measurement time points were scheduled to be taken, namely at study onset (T(1)) and after 6 months (T(2)). At either time point, two measurement series per subject were taken by the different examiners at 2-week intervals. The inter-examiner and intra-examiner agreement of the measurement results was assessed. The concordance for lightness and colour intensity (saturation) was represented by the intra-class correlation coefficient. The categorical variable colour shade (hue) was assessed using the kappa statistic. The study results show that tooth colour can be measured independently of the examiner. Good agreement was found between the examiners.

Assessing the effect of multibracket appliance treatment on tooth color by using electronic measurement.

BACKGROUND: The purpose of this study was to investigate how tooth color is affected by multibracket appliance (MBA) treatment. METHODS: The color of teeth #14 to #24 of 15 patients with MBA was measured on body and gingival tooth segments using the spectrophotometer Shade Inspector™. Colors of both segments were recorded before start of MBA treatment (baseline T0), end of MBA treatment (T1; 2 years ±0.3), and 3 months after T1 (T2). A 2D color system and a 3D system served as reference systems. Multilevel models were used to analyze color change within segments and to compare the difference in color change between segments (treatment effect). RESULTS: 2D system. Changes within tooth segments from T0 to T2 were at worst 2.0 units (ΔE in the gingival segment), which is less than the threshold of 2.7 units for a clinically meaningful difference. Confidence intervals for the treatment effect indicated no clinically important differences in color change between body and gingival segments. 3D system. Changes within tooth segments from T0 to T2 were at worst 2.3 units (ΔE in the body segment), which is less than the threshold of 2.7 units for a clinically meaningful difference. Confidence intervals for the treatment effect indicated no clinically important differences in color change between body and gingival segments. Thus, MBA treatment did not lead to clinically relevant changes in tooth color. CONCLUSION: Within the limitation of this study the MBA treatment can be seen as a safe method with respect to tooth color.

Experimental investigations into visual and electronic tooth color measurement.

OBJECTIVE: The present study aimed to examine the validity of the visual color assessment and an electronic tooth color measurement system by means of Shade Inspector™ in comparison with a gold standard. Additionally, reproducibility of electronic measurements was demonstrated by means of two reference systems. MATERIAL AND METHODS: Ceramic specimens of two thicknesses (h=1.6 mm, h=2.6 mm) were used. Three experienced dental technicians using the VITAPAN Classical(®) color scale carried out all visual tests. Validity of the visual assessment and the electronic measurements was confirmed separately for both thicknesses by means of lightness and hue of the VITAPAN Classical(®) color scale. Reproducibility of electronic measurements was confirmed by means of the VITAPAN Classical(®) and 3D-Master(®). The 3D-Master(®) data were calculated according to lightness, hue and chroma. Intraclass correlation coefficient (ICC) was used in assessing validity/reproducibility for lightness and chroma, Kappa statistics were used for hue. A level ≥0.75 was pre-established for ICC and ≥0.60 for the Kappa index. RESULTS OF VISUAL COLOR ASSESSMENT: Validity for lightness was good for both thicknesses; agreement rates for hue were inconsistent. ELECTRONIC MEASUREMENT: Validity for lightness was fair to good, hue values were below 0.60. Reproducibility of lightness was good to very good for both reference systems. Hue values (VITAPAN Classical(®)) for 1.6 mm test specimens were upside, for 2.6 mm below 0.60, Kappa values for 3D-Master(®) were ≥0.60 for all measurements, reproducibility of chroma was very good. CONCLUSION: Validity was better for visual than for electronic color assessment. Reproducibility of the electronic device by means of the Shade Inspector™ was given for the VITAPAN Classical(®) and 3D-Master(®) systems.