JC 2 Original Research on shade matching

shade matching

1. Effect of different instrumental techniques and clinical experience on shade matching Saygılı S, Albayrak B, Sülün T. Effect of different instrumental techniques and clinical experience on shade matching. Journal of Prosthodontics. 2024 Jun 13.

2. INTRODUCTION

3. Success of this stage depends on three major factors Correct determination of the current color of remaining dentition. Delivery of color and shape to laboratory with accurate data transfer method. Production of ceramic in such way as to achieve this harmony.

4. Two color systems used: Munsell color system CIELAB color system Munsell system includes: Hue Value Chroma CIELAB sytem includes: L* a* b* Δ E*ab and CIEDE2000 ( Δ E 00 ) .

5. Two different methods: Visual Instrumental Vita System 3D- Master- Value Vita Classical A1-D4- Hue Inconsistencies between shade tabs produced by same manufacturer. Inadequacies in variation of shade tabs. Lack of color standardization in ceramic products produced by different manufacturers. Spectrophotometers Colorimeters Intra oral scanners Digital Camera Vita Easy shade reveals best quality data in terms of accuracy and precision.

6. Digital photography important alternative in instrumental methods for determining color and transferring data to the technician more easily. Polychromatic colors in mouth Morphology Surface texture Translucency

7. Cross Polarization technique eliminate brightness of room where photograph was taken, reflection of flash on image caused by saliva, tooth structure, and restorations. Standard gray reference cards (white balance, Emulation) produced with L:79 a:0 b:0 are located next to teeth whose color determination is to be made. Reduces the glare created by the flash on the tooth by 30%. Current intraoral scanners also have color-determination functions. Devices such as TRIOS 3 allow color determination from any spot in accordance with both the Vita System 3D-Master and Vita Classical A1-D4 scales.

8. 9 01 02 03 Effect of clinical experience on shade matching. The color analysis success of intraoral scanners . AIM Evaluate the effect of the cross polarization technique used in digital photographs.

9. HYPOTHESIS 01 02 03 10 cross-polarization technique has no effect on shade matching. there is no difference in the success of groups with different clinical experience levels . intraoral scanners successfully determine color.

10. MATERIAL AND METHODS The study protocol was approved by the Istanbul University Faculty of Dentistry, Clinical Research Ethics Committee. 12 people in four different groups, based on the correct match rates of the research conducted by Schropp et al. Ten undergraduate dentistry students between 22 and 25 years old were selected.

11. 12 absence of tooth loss in the anterior region the absence of discoloration of the anterior teeth due to any restoration, root canal treatment Students who had bleaching treatment in the last 6 months and insufficient oral hygiene INCLUSION CRITERIA EXCLISION CRITERIA

12. Color measurements were performed with spectrophotometer (Vita Easyshade Advance 4.0 ), which is accepted as the gold standard. 1 Then, digital impressions were made from all participants with the TRIOS 3 intraoral scanner (3Shape Trios A/S) 2 Color measurements were made center of maxillary right central tooth using the scanner software (3Shape Dental Software), according to Vita System 3D-Master scale and the values were recorded.

13. 3 Ambient light between 5500 and 6500 K used in the photography room. Before photographing, maxillary central tooth-lens distance was set 45 cm. NON POLARIZED DIGITAL DENTAL PHOTOGRAPH POLARIZED DIGITAL DENTAL PHOTOGRAPH L: 79 a: 0 b: 0

14. Non Polarized Shade Tab Polarized Shade Tab

15. 48 observers from four different academic groups with different levels of experience were selected Faculty Staff Post Graduate Students Under Graduate Interns Dental Technicians Answers given by each observer was recorded. Difference between shade choices made by observers and actual maxillary central tooth values of the subject students the CIEDE2000 color difference (ΔE00) was calculated as follows

16. Data for normal distribution was examined with the Shapiro-Wilk test. Independent Samples t-test was used to compare normally distributed data between two groups. Repeated Measures Analysis was used to compare ΔE00 value, which was normally distributed according to observer groups, and multiple comparisons were examined with Bonferroni test.

17. The compatibility of the intraoral scanner and the spectrophotometer was examined with Kappa. 0.05 was used as level of significance.

18. RESULTS Forty-eight observers performed shade matching on a total of 20 photographs taken with non-polarized and cross-polarized techniques from 10 student participants.

19. The color of Vita System 3D-Master scale obtained with spectrophotometer was compared with colors specified by software from same point in intraoral scans. The kappa value (κ) between TRIOS 3 and Vita Easyshade was 0.10, was not statistically significant.

20. DISCUSSION

21. Non polarized technique- superior results for Post graduate students leads to partial rejection of first hypothesis. No difference between shade matchings of groups in cross-polarization technique, undergraduate students were found to be statistically unsuccessful in non-polarization technique compared to other groups

22. The third hypothesis that intraoral scanners would be successful in color determination was completely rejected. kappa value was below 0.20, it is considered poor in terms of strength of agreement.

23. Color determination Intra oral scanners Vita system 3D- Master Scale Rutkunas et al reported that color analyses performed by intraoral scanners with different scales can give various results. Visual color selection: subjective, operator-dependent highly influenced by existing light sources instrumental shade-matching techniques appear to be more reliable .

24. In color analysis performed on digital photographs, screen features and colorimeter software on which photograph is evaluated may also affect the results. Acc to Paravina et al, the acceptability thresholds were as: ≤0.8, excellent match ≤1.8, acceptable match ≤3.6 , moderately unacceptable ≤5.4, clearly unacceptable >5.4, extremely unacceptable

25. In a study on undergraduate students conducted by Clary et al, shade matchings were made on shade tabs, then students were subjected to a lesson on color and repeated their shade matchings. Yoon et al, who measured the color determination performance of intraoral scanners on shade tabs, reported that results of scanners and the colorimeter were not consistent.

26. CRITICAL APPRAISAL Shade matching was carried out on young undergraduate with intact teeth. Only one intra oral scanner was used in this present study.

27. CROSS REFRENCES

28. Intraoral scanner does not exactly match the Spectrophotometer in determining tooth color. The software of the intraoral digital scanner does not provide actual L, a, and b values. The accuracy of the intraoral scanner is higher when the color is recorded as Vita 3D Master values rather than as Vita Classical values. Rutkūnas V, Dirsė J, Bilius V. Accuracy of an intraoral digital scanner in tooth color determination. The Journal of prosthetic dentistry. 2020 Feb 1;123(2):322-9.

29. The digital photographs taken by using the cross polarizing filter enabled results similar to those of the spectroradiometer for the low-in-value shade table (5M3). Whereas, for the high-in-value shade table (1M1), the results obtained without a cross-polarizing filter were closer to those of the spectroradiometer. Yilmaz B, Dede DÖ, Diker E, Fonseca M, Johnston WM, Küçükekenci AS. Effect of cross‐polarization filters on the trueness of colors obtained with a single‐lens reflex camera, macro lens, and a ring flash. Journal of Esthetic and Restorative Dentistry. 2023 Sep;35(6):878-85.