ORIGINAL ARTICLES
CONVENTIONAL VERSUS SPECTROPHOTOMETRIC SHADE TAKING FOR THE UPPER CENTRAL INCISOR: A CLINICAL COMPARATIVE STUDY Anca Jivanescu, Corina Marcauteanu, Daniel Pop, Luciana Goguta, Dorin Bratu
REZUMAT Introducere: Restaurarea unui singur incisiv central superior reprezintă o adevărată provocare pentru echipa medic dentist- tehnician dentar. Corecta alegere, comunicare şi reproducerea cat mai precisă a culorii incisivului central superior reprezintă cheia succesului în cazul tratamentului restaurator protetic. Obiectiv: avestui studiu a fost determinarea variabilităţii între diferiţi observatori în ceea ce priveşte alegerea culorii unui incisiv central superior, utilizand două chei de culori (Vita Classic şi Vitapan 3D Master) şi compararea rezultatelor cu cele obţinute cu ajutorul spectrofotometrului Vita Easy Shade. Material si metodă: Studiul a implicat 26 de studenţi ai Facultăţii de Medicină Dentară, care au examinat culoarea incisivului central la 4 pacienţi cu ajutorul a două chei de culori convenţionale (Vita Classic si Vitapan 3D Master). Rezultatele au fost comparate cu cele obţinute cu spectrofotometrul Vita Easy Shade. Pentru compararea rezultatelor între determinările făcute de studenţi şi cele făcute de spectrofotometru s-a utilizat un software de analiza statistică IBM SPSS Statistics (Version 19). Rezultate: Procentajul de corelaţie calculat a fost de 37,5 % pentru cele două chei de culori utilizate. Concluzia: acestui studiu a fost că determinarea culorii in cazul incisivului central cu ajutorul cheilor de culori prezintă variaţii destul de mari între diferiţi examinatori, iar spetrofotometrul Vita Easy Shade poate fi un util mijloc educaţional . Cuvinte cheie: alegerea culorii dinţilor, cheie culori, spectrofotometru
ABSTRACT Introduction: Restoration of a single upper central incisor is one of the most challenging situations for the dentist-dental technician team. Proper selection, communication and more accurate color reproduction of the upper central incisor is the key to a successful prosthodontic treatment. The objective of this study was to determine the inter-observer variability in shade selection for the upper central incisor when using two shade guides (Vita Classic and Vitapan 3D Master) and to compare the results with those of Vita Easy Shade spectrophotometer. Material and method: The study involved 26 students of the Faculty of Dentistry, who examined the color of central incisor for 4 patients with conventional shade guides. Standard conditions were used to choose the color and determinations were made independently by two shade guides, Vita Classic and Vita 3D Master. The results were compared with those obtained by using the Vita Easy Shade spectrophotometer. The IBM SPSS Statistics (Version 19) software was used to statistically compare the results of the students with the spectrophotometer results. Results: A frequencies analysis concluded that the correlation percentage between the determinations of the students and the spectrophotometer was 37.5% for both Vita Classic and Vitapan 3D Master shade guide. Conclusion: this study showed that there are some large variations in color determination for the upper central incisor by using 2 conventional shade guides and the spectrophotometer may be a useful educational tool. Key Words: tooth shade match, shade guide, spectrophotometer
INTRODUCTION Department of Prosthodontics, Victor Babes University of Medicine and Pharmacy Timisoara, Faculty of Dentistry Correspondence to: Anca Jivănescu, Victor Babeş University of Medicine and Pharmacy Timişoara, Faculty of Dentistry, Department of Prosthodontics, Timisoara, Anghel Saligny str., No 17, Tel: 0744-570488. E-mail:
[email protected] Received for publication: Oct., 2010. Revised: Nov. , 2010. _____________________________
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The aesthetic restoration means a similar shape and color of related teeth. Determination and precise communication of color is a requirement for a successful restoration and for obtaining an aesthetic harmony. Often young professionals are faced with situations where the correct choice of color is a very difficult task, which can lead to unwanted errors. Tooth shade matching in prosthetic dentistry involves five steps:1
• Analysis of color; • Color communication to the dental technician; • Interpretation of the color information in the ceramic part selection; • Making the restoration; • Color verification before the final cementation in the mouth. According to a study conducted in 2002 in Dental Lab Products Report, almost half of the dentists have modified the technique of choosing the color for the upper central incisor2. Since the traditional techniques of choice for shade guides are subjective, the modern digital devices of color analysis allow precise and standardized measurements. In the last two decades, the use of colorimeters and spectrophotometers became more frequent. Colorimeter first appeared in 1870, but by 1990 the primary use was in chemistry. Douglas said that in the oral cavity, the resolution of digital colorimeters is about as close as the human eye.3 Spectrophotometric analysis is based on the wave length reflected by the tooth. The rays reflected from the tooth are captured by an optical instrument and are measured, in comparison with those from the database provided by the shade guides. This technology measures 300,000 spectral curves, which includes 6 million of reference points based on different wave lengths.4 The spectrophotometer measures numerous points along the visible spectrum and can be used to determine the values of CIE L* a* b*. Spectrophotometer is an accurate device by itself and it is independent of the light source or filters. The spectrophotometer measures the closest shade to the traditional shade guides (Vita Classic and Vitapan 3D Master). Using the digital system will implicate the measurement of the parameter ΔE, which records the difference between two colors.5
1. Vita Classic (16 color tabs guide) 2. Vitapan 3D master (the 26 colors of Vita 3D Master shade guide are arranged according to the degree of clinical crown value). Examinations were held in a separate room, not to be influenced by the other subjects. Time of determination for each shade guide was about 1 minute for every 4 patients. The conditions of tooth shade match were: natural light, a sunny day at noon, in front of the window. Patients’ clothes were covered with a graywhite material. First, the students started the color determination with the help of Vita Classic shade guide, followed by Vitapan Master 3D shade guide. (Fig. 1, 2)
Figure 1. The shade determination for the upper central incisor with Vita Lumin Vacuum shade guide
MATERIAL AND METHOD Our study involved 26 students of the Faculty of Dentistry. First, the visual acuity was determined, for the 26 volunteers. We have used a training program, an educational software provided by Paravina4 which has tested the ability of differentiating the value, the chroma and hue. In this study were selected only those students who had no chromatic perception disabilities (a test score above 80%). In the present study was analyzed the tooth shade of the upper central incisor for 4 patients (2 men and 2 women), with the help of 2 shade guides. The shade guides were as follows:
Figure 2. The shade determination for the upper central incisor with Vitapan 3D Master shade guide
Finally, the instructor determined the color by using the spectrophotometer Vita Easy Shade. (Fig.3) In this case the light or environment conditions did not influence the results. _____________________________ Anca Jivanescu et al
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Table 1. Results for tooth shade determination for patients A, B, C and D. Number
Student gender 1 M 2 M 3 F 4 F 5 M 6 M 7 F 8 M 9 F 10 M 11 F 12 F 13 F 14 F 15 M 16 M 17 F 18 M 19 F 20 F 21 F 22 F 23 F 24 M 25 F 26 F Vita Easy Shade spectrophotometer
Patient A Vitapan 3D Master 1M1 2M1 2M1 2L1,5 1M1 2R1,5 2M1 3M1 1M2 2M1 2L1,5 2L1,5 2M1 2M1 2M1 2M1 2M1 1M1 2L1,5 2L1,5 2M1 1M1 2M1 1M1 2M1 2L1,5 2M1
Vita Classic A1 D2 B1 D2 B1 B1 B1 D2 D2 A1 D2 B2 B1 B1 B1 B1 A2 A1 C1 B1 A1 B1 B1 B1 B1 D2 B1
Patient B Vitapan 3D Master 2M2 2M1 2L2,5 2L1,5 2M1 2L1,5 2M1 2L1,5 2M2 2M1 2L1,5 2L2,5 2M2 2L1,5 2M2 2M1 2M2 2L1,5 2L1,5 2L1,5 2L1,5 2M2 2M1 2M2 2L1,5 2L2,5 2M1
Vita Classic A3 D3 B1 D2 B2 B3 B2 D2 D2 A3 D3 B3 B2 B3 D2 B1 A3 A2 D2 B3 A3 B3 B3 B2 D2 D2 D2
Patient C Vitapan 3D Master 1M2 2M1 1M1 2L1,5 1M1 2R1,5 1M1 1M2 2M2 2M1 2L1,5 2L1,5 1M1 1M1 1M1 2M1 1M1 1M1 2L1,5 2L1,5 2M1 1M1 1M1 1M1 1M1 2L1,5 1M1
Vita Classic A2 D2 B1 D2 B1 B1 B1 D2 D2 A1 D2 B2 B1 B1 B1 B1 A2 A1 C1 B1 A1 B1 B1 B1 B1 D2 B1
Patient D Vitapan 3D Master 2M2 2M1 2L1,5 2L1,5 1M2 2R1,5 2M1 2M1 1M2 2M1 2L1,5 2L1,5 2L2,5 2M1 2M1 2M1 2L2,5 2M1 2L1,5 2L1,5 2M1 2L1,5 2M2 2M1 2L1,5 2L1,5 2L1,5
Vita Classic A2 A1 B1 D2 B1 B1 B1 A1 D2 A1 A1 B2 B1 B1 B1 B1 A2 A1 C1 B1 A1 B1 B1 B1 B1 D2 A1
Table 2. ΔE results obtained for all patients and ΔE mean for each patient and shade guide Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 ΔE mean
Student gender M M F F M M F M F M F F F F M M F M F F F F F M F F
Patient A Vitapan 3D Master 5.39 0 0 4.67 5.39 2.41 0 4.91 7.74 0 4.67 4.67 0 0 0 0 0 5.39 4.67 4.67 0 5.39 0 5.39 0 4.67 2.69
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Vita Classic 2.9 5.44 0 5.44 0 0 0 5.44 5.44 2.9 5.44 5.67 0 0 0 0 7.12 2.9 4.64 0 2.9 0 0 0 0 5.44 2.37
Patient B Vitapan 3D Master 5.94 0 10.62 4.67 0 4.67 0 4.67 5.94 0 4.67 10.62 5.94 4.67 5.94 0 5.94 4.67 4.67 4.67 4.67 5.94 0 5.94 4.67 10.62 4.62
Vita Classic 8.37 5.31 5.44 0 7.23 11.87 7.23 0 0 8.37 5.31 11.87 7.23 11.87 0 5.44 8.37 7.39 0 11.87 8.37 11.87 11.87 7.23 0 0 6.25
Patient C Vitapan 3D Master 6.36 5.39 0 7.26 0 6.71 0 6.36 8.66 5.39 7.26 7.26 0 0 0 5.39 0 0 7.26 7.26 5.39 0 0 0 0 7.26 3.59
Vita Classic 7.12 5.44 0 5.44 0 0 0 5.44 5.44 2.9 5.44 5.67 0 0 0 0 7.12 2.9 4.03 0 2.9 0 0 0 0 5.44 2.51
Patient D Vitapan 3D Master 1.69 4.67 0 0 5.01 2.92 4.67 4.67 5.01 4.67 0 0 6.02 4.67 4.67 4.67 6.02 4.67 0 0 4.67 0 1.69 4.67 0 0 2.89
Vita Classic 6.23 0 2.9 7.64 2.9 2.9 2.9 0 7.64 0 0 4.54 2.9 2.9 2.9 2.9 6.23 0 6.16 2.9 0 2.9 2.9 2.9 2.9 7.64 3.22
Figure 6. ΔE values for patient C.
Figure 3. The color (shade) determination for the upper central incisor with the Vita Easy Shade spectrophotometer
RESULTS This study has been conducted on 26 students of the Faculty of Dentistry analyzing the tooth shade of an upper central incisor in 4 patients (2 men and 2 women), with the help of 2 shade guides: Vita Classic and Vitapan 3D Master. The shade perception of the students was compared with the shade as obtained by the Vita Easy Shade spectrophotometer. The results of determinations are listed in the table below. The difference of shade was computed using the CIE L* a* b* mean values of each shade from both shade guides with the ΔE formula: ΔE=((L*1-L*2)2 + (a*1 – a*2)2 + (b*1 - b*2)2)1/2, Where (L*1,a*1,b*1) is the CIE L* a* b* of the shade computed by the spectrophotometer and (L*2,a*2,b*2) is the CIE L* a* b* of the shade perceived by the student. The ΔE values are listed in the Table 2. The ΔE values resulting from the ratings of each student can be viewed per patient in Figures 4-7.
Figure 4. ΔE values for patient A.
Figure 5. ΔE values for patient B.
Figure 7. ΔE values for patient D.
The ΔE mean was also computed for all patients for each shade guide. The result was similar between the 2 shade guides, Vitapan 3D Master having a ΔE mean of 3.45 and Vita Classic a ΔE mean of 3.59. The IBM SPSS Statistics (Version 19) software was used to statistically compare the results of the students with the spectrophotometer results. A frequencies analysis concluded that the correlation percentage between the determinations of the students and the spectrophotometer is 37.5% for both Vita Classic Shade Guide and Vitapan 3D Master Shade Guide. This can be observed in Table 3 on the first line, frequencies corresponding to the ΔE value “00” and in Table 4 also on the first line, frequencies corresponding to the ΔE value “00”. Table 3. Frequencies of ΔE values obtained with the Vita Classic Shade Guide Delta E obtained with Vita Classic Frequency Valid .00 39 2.90 20 4.03 1 4.54 1 4.64 1 5.31 2 5.44 14 5.67 2 6.16 1 6.23 2 7.12 3 7.23 4 7.39 1 7.64 3 8.37 4 11.87 6 Total 104 Missing System 728 Total 832
Percent 4.7 2.4 .1 .1 .1 .2 1.7 .2 .1 .2 .4 .5 .1 .4 .5 .7 12.5 87.5 100.0
Valid Percent 37.5 19.2 1.0 1.0 1.0 1.9 13.5 1.9 1.0 1.9 2.9 3.8 1.0 2.9 3.8 5.8 100.0
Cumulative Percent 37.5 56.7 57.7 58.7 59.6 61.5 75.0 76.9 77.9 79.8 82.7 86.5 87.5 90.4 94.2 100.0
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Table 4. Frequencies of ΔE values obtained with the Vitapan 3D Master Shade Guide Delta E obtained with Vitapan 3D Master Frequency Valid .00 39 1.69 2 2.41 1 2.92 1 4.67 26 4.91 1 5.01 2 5.39 9 5.94 7 6.02 2 6.36 2 6.71 1 7.26 6 7.74 1 8.66 1 10.62 3 Total 104 Missing System 728 Total 832
Percent 4.7 .2 .1 .1 3.1 .1 .2 1.1 .8 .2 .2 .1 .7 .1 .1 .4 12.5 87.5 100.0
Valid Percent 37.5 1.9 1.0 1.0 25.0 1.0 1.9 8.7 6.7 1.9 1.9 1.0 5.8 1.0 1.0 2.9 100.0
Cumulative Percent 37.5 39.4 40.4 41.3 66.3 67.3 69.2 77.9 84.6 86.5 88.5 89.4 95.2 96.2 97.1 100.0
The same results can be observed in Fig. 8 and 9.
Figure 8. Frequencies of ΔE values obtained with the Vita Classic shade guide
Figure 9. Frequencies of ΔE values obtained with the Vitapan 3D Master shade guide _____________________________
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DISCUSSION Finding the correct color for a successful aesthetic treatment is a mandatory requirement. In 1998 Okubo and al compared the results of using Vita shade guide and a dental colorimeter.6 Tung and collaborators reported that, when using Vita shade guide by experimented dentists, the correlations with the colorimeter determinations tend to be over 60%.7 Studies by Paul and others have shown a correlation of 27% in color reproducibility among practitioners who took the shade with the shade guide for central incisors of 30 patients.8 In the same time, 3 determinations with the spectrophotometer showed a reproducibility of 83%. Another clinical study conducted by Paul and collaborators revealed that the shade determination for porcelain fused to metal crown by spectrophotometer is superior to visual method with the shade guide.9 Paravina analyzed and compared the arrangement of Vita Classic and Vitapan 3D Master shade guides.10 They concluded that 3D Master key arrangement is more realistic and suggested arranging the Vita Classic shade guide according to brightness. The conclusion was that the use of 3D Master shade guide decreases the possibility of errors and increases the intermediate precision among practitioner’s different determinations. Dancy and others reported that digital shade match can serve as an alternative to conventional visual methods for restoring anterior teeth with all ceramic crowns.11 A study conducted by Douglas compared the ability to reproduce the color of the target shade tab and concluded that most crowns fabricated by the laboratories in this study, when compared to the prescribed shade tab, were above the clinical threshold for an acceptable shade match under intraoral conditions.12 In a recent clinical study, crowns fabricated using a dedicated spectrophotometer had a significantly better color match and a lower rate of rejection due to shade mismatch compared to crowns fabricated with a conventional shade-matching method.13 In our study, observers were students in the 6-th year of the Faculty of Dentistry. The purpose of this study was the analysis of repeatability determinations made by the students with the 2 shade guides and the correspondence determinations measured by the Vita Easy Shade. The mean ΔE was computed for all patients for each shade guide. The result was similar between the 2 shade guides, Vitapan 3D Master having a ΔE mean of 3.45 and Vita Classic a ΔE mean of 3.59.
The IBM SPSS Statistics (Version 19) software was used to statistically compare the results of the students with the spectrophotometer results. A frequencies analysis concluded that the correlation percentage between the determinations of the students and the spectrophotometer is 37.5% for both Vita Classic Shade Guide and Vitapan 3D Master Shade Guide
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CONCLUSION
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In this study, it can be concluded that the shade matching for the upper central incisor with conventional shade guide highlights a marked variation between observers. The ratings with Vitapan 3D Master shade guide are more accurate. The Vita Easy shade spectrophotometer can be a useful educational tool for the color management in dental schools.
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REFERENCES
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Chu SJ. Clinical steps to predictable color management in aesthetic restorative dentistry. Dental Clinics of North America, 2007;51(2):473-485.
Chu SJ. Communicating and verifying tooth shade using the electronic shade matching system. Dental Lab Products Report, sept 2002. Douglas RD. Precision of in vivo colorimetric assessment of teeth. J Prosthet Dent 1997;77:464-70. Paravina R, Powers J. Esthetic color training in dentistry, Mosby 2004(book and CD) J.Brewer, A.Wee, R.Seghi. Advances in color matching. Dental Clinics of North America, 2004; 48(2): 341-58. Okubo SR, Kanawati A, Richards MW, et al. Evaluation of visual and instrument shade matching. J Prosthet Dent 1998;80:642-8. Tung FF, Goldstein GR, Jang S, et al. The repeatability of an intraoral dental colorimeter. J Prosthet Dent 2002; 88:585-90. Paul SJ, Peter A, Pietrobon N, et al. Visual and spectrophotometric shade analysis of human teeth. J Dent Rest 2002;81;578-82. Paul SJ, Peter A, Rodoni L, et al. Conventional visual vs. spectrophotometric shade taking for porcelain-fused-to-metal crowns: a clinical comparison. Int J Periodontics Restorative Dent 2004;24:222-31. Paravina RD, Powers JM, Fay RM. Dental color standards: shade tab arrangement. J Esthet Restor Dent 2001; 13:254-63. Dancy WK, Yaman P, Dennison JB, et al. Color measurements as quality criteria for clinical shade matching of porcelain crowns. J Esthet Restor Dent 2003,15(2):114-21. Douglas RD, Brewer JD. Variability of porcelain color reproduction by commercial laboratories. J Prosthet Dent 2003;90:339-46. Da Silva, Park S, Weber H, et al. Clinical performance of a newly developed spectrophotometric system on tooth color reproduction. The Journal of Prosthetic Dentistry 2008;99(5): 361-8.
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