Clinical Performance Of A Newly Developed Spectrophotometric

Purpose:The purpose of this in vitro study was to evaluate the reliability and accuracy of a dental clinical shade-matching instrument in a standardized environment. To study the feasibility of the clinic application of the Crystaleye spectrophotometer, the clinical effect of two clinical shade-matching methods, one applied Crystaleye spectrophotometer (OLYMPUS, CE100-DC/US) and the other one was conventional visual shade, was compared.Methods:4 commercial shade guides (Vitapan classical,Vita toothguide 3D-Master,Noritake and Ivoclar Vivadent Chromascop) were tested with the Crystaleye Spectrophotometer, shade-matching instrument. Shade tabs were selected and placed in the middle of a gingival matrix (Shofu Gummy). Measurements were made of the cervical, middle, and incisal regions of the shade tab inside a Crystaleye checkbox (CE100-MK). For the reliability assessment, each tab from the 4 shade guide types was measured 10 times and for the accuracy, each tab was measured once. All results were recorded and calculated for each shade guide and region using computer software (Crystaleye Application Ver.1.3). Differences were determined by one-way ANOVA using SPSS 13.0 software program.63 patients in need of an anterior or a first premolar Ni-Cr porcelain-fused-to-metal crown were in enrolled in this study randomly.2 crowns (crown V and crown S) were prepared for each patient. Crown V was made via conventional visual matching by a commercial shade guide, Vitapan classical method. Crown S was made via a new computer system, Crystaleye spectrophotometer. Crystaleye spectrophotometer was also applied to measure the color of the natural teeth and crowns. The color difference values (DeltaE) between the contralateral natural tooth and each of the 2 crowns were calculated in the middle regions. A paired-samples t test was performed based on the DeltaE using SPSS 13.0 software package. The color reproducibility of crown V and crown S was evaluated by patients (p) and prosthodontists (d) visually using double-blind method (Vp,Vd,Sp,Sd). The results were evaluated by Chi-square test.Results:The reliability of Crystaleye Spectrophotometer was as follows:a significant difference was found in regions of shade tabs (P<0.05). The middle region showed the highest reliability while the incisal region had the lowest reliability. A significant difference was found between the different shade guides as well (P＜0.05). There was a significant difference between Vitapan classical and Vita toothguide 3D-Master in the cervical and middle regions (P<0.0083). The reliability of Vitapan was lower than Vita toothguide 3D-Master. In the incisal region Ivoclar Vivadent Chromascop had the lowest reliability of all the shade guides tested. The accuracy of Crystaleye Spectrophotometer was as follows:there was a significant difference between all regions (P＜0.05). The middle region had the highest accuracy while the cervical and incisal regions were nearly the same. No significant difference was found between the four shade guides (P<0.05). There was significant difference in the mean DeltaE between crown V(3.13±0.80) and crown S (2.68±0.72)(P＜0.01). Results of visual evaluation were as follows:no significant difference was found between crown Vp and crown Sp (P=0.035); the significant difference was found between crown Vd and crown Sd (P＜0.001); there was also significant difference between crown p and d(P＜0.001).Conclusions:This in vitro study showed a varying degree of reliability and accuracy for Crystaleye Spectrophotometer, depending on the type of shade guide system and regions used. The Crystaleye Spectrophotometer showed a very high degree of reliability and accuracy in middle region. According to this clinical study, the crowns fabricated applying a dedicated spectrophotometer had a better color matching compared to the ones fabricated via a conventional shade-matching method. The conclusion was drawn that the Crystaleye spectrophotometer is proved to be a promising and suitable instrument for determining tooth color in clinic in a standardized environment.