Agreement of Try-In Pastes and the Corresponding Luting Composites on the Final Color of Ceramic Veneers Binting Xu, DDS, PhD,1,∗ Xiaodong Chen, DDS, PhD,1,2,∗ Rong Li, DDS, PhD,1 Yining Wang, DDS, PhD,3 & Qing Li, DDS, PhD4 1
Postgraduate Student, School and Hospital of Stomatology, Wuhan University, Wuhan, China Department of Prothodontics, Dalian Stomatological Hospital, Dalian, China 3 Professor, Director of Department of Prosthodontics, Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China 4 Associate Professor, Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China 2
Keywords Ceramic veneer; luting composite; try-in paste; color difference. Correspondence Yining Wang or Qing Li, Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237# Luoyu Road, Wuhan, China. E-mail: [email protected] or [email protected] ∗
These authors contributed equally to this study. Supported by the Fundamental Research Funds for the Central Universities (No. 201130402020002), China Postdoctoral Science Foundation funded project (No. 20100480870), National Natural Science Foundation of China (No. 81100784), and National Natural Science Foundation of China (No. 81070853).
Abstract Purpose: The aims of this study were to evaluate the influence of luting composites on the final color of ceramic veneers and to investigate the color matching of try-in pastes to the corresponding luting composites. Materials and Methods: Ceramic discs (shade A3, 1.0 mm thick) were fabricated and seated on composite specimens (shade A3) to mimic a complex of ceramic veneer lying on dentin substrate. The try-in pastes and luting composites of 3M RelyX were applied into the interlayer of the ceramic and composite specimens. The colors of the complexes were measured using a spectrophotometer, and subsequently converted to CIE L*a*b* values. Color changes after luting composites were applied, and the changes between the try-in pastes and the corresponding luting composites were calculated and registered as Eluting and Epaste-luting . Color measurements were repeated while the ceramic specimens were reduced to 0.7 mm and then 0.5 mm in thickness. Results: The means of Eluting were 0.69 ± 0.21, 1.27 ± 0.48, and 1.40 ± 0.57 for the 1.0, 0.7, and 0.5 mm thicknesses, respectively. Two-way ANOVA revealed that Epaste-luting values were significantly affected by the colors of luting composites and veneer thickness (p < 0.001). Lighter shades of luting composites showed less influence on Epaste-luting values. Conclusions: Luting composites could slightly modify the final color of ceramic veneers. Color matching of a try-in paste to the corresponding luting composite was not always achieved in the 0.7 or 0.5 mm thicknesses.
The authors deny any conflicts of interest. Accepted July 10, 2013 doi: 10.1111/jopr.12109
Esthetic dentistry attaches importance to the conservation of healthy tooth structure integrated with biologic and long-term functional requirements. Since the first published article on porcelain veneering,1 the ceramic laminate veneer has become a popular technique for improving the appearance of anterior teeth. This technique allows for less-aggressive tooth removal than full coverage restorations and demonstrates excellent clinical performance in terms of periodontal reaction and biocompatibility, which favor a healthy gingival response.2,3 To obtain a durable bonding strength for ceramic veneers, tooth reduction should remain within the enamel layer, which 308
is described as 0.7 to 0.8 mm thick.2 As a result, ceramic laminate veneers are ideally thin and relatively translucent. The color of tooth substrate or luting composites might potentially influence the final color of veneer restorations.4-6 It is essential to gain the approval of the patient before final cementation takes place.7 However, it is a challenge for dentists to predict the resultant color of ceramic veneers. Several approaches have been described to mask discolored tooth substrate and adjust the final appearance of the restorations. These approaches include the application of more opaque porcelain8 or the use of different colors of luting composites.9 An opaque ceramic layer will
C 2014 by the American College of Prosthodontists Journal of Prosthodontics 23 (2014) 308–312
Xu et al
compromise the esthetics of veneer restorations.2,10 Therefore, the application of different color luting composites seems to be a promising approach for adjusting the resultant color.11 Manufacturers have introduced several adhesive systems for ceramic veneers, including various colors of luting composites and the corresponding try-in pastes. They have claimed that the luting composites of various shades could be used to modify the final color of the veneers to attain color matching. The try-in pastes could be used as indicators of the final color and as a guide to choose an appropriate color of the luting composites; however, there is no agreement in the literature about the influence of the luting composites on the resultant color of ceramic veneers. Moreover, controversial viewpoints, concerned about the color agreement of try-in pastes and luting composites, have been proposed. ALGhazali et al noted the clinically significant color differences between a try-in paste and the luting composite of the same shade.12 On the other hand, high agreement of the try-in paste and the corresponding luting composite has also been reported.13,14 The purposes of this study were to evaluate the influence of the luting composites on the resultant color of ceramic veneers, and to investigate color agreement of try-in pastes to the corresponding luting composites. The null hypotheses were that there was no difference in the color of the final restorations achieved using various shades of luting composites, and there was no perceptible color difference between the try-in pastes and the corresponding luting composites.
Materials and methods Pressable lithium disilicate glass-ceramic discs (IPS e.max; Ivoclar, Schaan, Liechtenstein) and composite specimens (Amelogen Plus; Ultradent, South Jordan, UT) were fabricated to represent ceramic veneers and backgrounds with various colors. An adhesive system (RelyXTM Veneer; 3M ESPE, St. Paul, MN) with five shades of try-in pastes and luting composites (Translucent, B0.5, A1, A3, White Opaque) was included in the study (Table 1).
Fabrication of ceramic veneers and backgrounds
Disc-shaped ceramic specimens (nominal shade A3 to Vita Lumin, 10 mm in diameter) were fabricated by the lost-wax technique in accordance with the manufacturer’s instructions. Wet silicone carbide paper (600-, 800-, 1000-, 1500-grit) was used to polish the specimens and achieve a thickness of 1.0 ± 0.01 mm (n = 10) using a digital micrometer (Mitutoyo, Tokyo, Japan). Finally, a self-glazing process was performed at the manufacturer’s recommended temperature. No internal or external staining was used in the fabrication procedure. Composite discs (10 mm diameter, 4.0 mm thick, shade A3) were fabricated and served as the background colors to mimic the prepared dentin substrate. To avoid the color measurement errors caused by the mismatched position, notches were cut in the edge of each quarter of the specimens (Fig 1).
Validity of Try-In Paste as an Indicator for Veneer’s Color
Application of adhesive agents
The ceramic specimens were placed on the composite discs with notches matched. Try-in pastes or the corresponding luting composites were applied between the ceramic and composite specimens to build up the veneer/cement/background complexes. The complexes were registered as TP group (try-in paste) or LC group (luting composite) according to the adhesive agents applied. Complexes with a refractive liquid (with an index of refraction of 1.50) applied between the ceramic and background to achieve the optical connection15 served as the control group (baseline). Pressure (200 g) was applied on the top surface of the ceramic veneers for 10 seconds. Then 40 seconds of light curing was performed for the LC group. For the convenience of the separation from the composite background, the ceramic veneers were not acid etched, and no coupling agent was used. Color measurements
The color measurement apparatus consisted of a spectrophotometer (PR-650 Spectra Scan, equipped with MS-75 and SL0.5X lens; Photo Research, Chatsworth, GA) and two fiber optic light cables. The optic light cables, positioned at a 45◦ angle right-and-left to the spectrophotometer, provided an optical configuration of 0◦ observation and 45◦ illumination, recommended by Bolt et al for measuring the color of translucent materials.16 The spectrophotometer was standardized to 91.4 mm from the measured object with a measurement aperture size 1.5 mm in diameter. The standardized illumination source D65 (Model OL 53; Optronic Laboratories, Orlando, FL) and 2◦ observer configuration were used. For the color measurements, spectral reflectance was obtained from 380 to 780 nm (2 nm interval) and subsequently converted to the CIE L*a*b* values established by Commission International de L’Eclairage (CIE).17 Before each session of measurement, the spectrophotometer was calibrated with a white reflectance standard tile supplied by the manufacturer. A customized jig with a pointer was used to hold the specimens and confirm the position of the notches in the specimens (Fig 1). Color errors of 1-week repeated measurements using this instrumental measuring system were less than 0.027 per E unit.18 After each measurement, the veneer was separated from the composite background, and both of the veneers and the composite backgrounds were polished using 1500-grit silicone carbide paper to remove the adhesive layer. Then, an assembling procedure with another color of luting agents was performed. After the first session of color measurements, the veneers were decreased to 0.7 mm, and then 0.5 mm, in thickness. The color measurements were repeated. Statistical analysis
Color differences between the control and LC groups (registered as Eluting ), or between TP and LC groups (registered as Epaste-luting ) were determined by the equation: E = [(L*)2 + (a*)2 + (b*)2 ]1/2 .19 Color parameters L*, a*, and b* presented the differences in lightness, the green-red coordinate, and the blue-yellow coordinate, respectively. Two-way ANOVA was used to analyze the effects of veneer thickness and luting composite color on Epaste-luting values. Tukey’s post
C 2014 by the American College of Prosthodontists Journal of Prosthodontics 23 (2014) 308–312
309
Validity of Try-In Paste as an Indicator for Veneer’s Color
Xu et al
Table 1 All-ceramic veneer adhesive system used Materials TM
RelyX
Veneer
Shade
Code
Batch number
Manufacturer
Translucent B0.5 A1 A3 White opaque
TR B0.5 A1 A3 WO
8CU, 8FJ 8BY, 8CW 8CA, 8EF 8BX, 8CT 8CA, 8CX
3M ESPE, St. Paul, MN
Figure 1 Specimens on the positioning jig and color measuring system. (A) a: holder for specimens, b: ceramic veneer, c: pointer. (B) a: PR650 spectrophotometer, b: D65 light source, c: specimen on the jig.
Table 2 Means of Eluting values with different ceramic thickness Thickness 1.0 mm 0.7 mm 0.5 mm
n 50 50 50
Mean of Eluting (SD) Source
a
0.69 (0.21) 1.27 (0.48)b 1.40 (0.57)b
Different superscript letters indicate significant difference.
hoc comparisons were performed to evaluate the differences among various luting composite colors. SPSS statistical software (SPSS 13.0 for Windows, SPSS, Chicago, IL) was used for the analysis. The level of significance was established at α = 0.05.
Results The means of Eluting were 0.69 ± 0.21, 1.27 ± 0.48, and 1.40 ± 0.57 for 1.0, 0.7, and 0.5 mm thicknesses, respectively (Table 2). ANOVA results revealed that Eluting values in group 1.0 mm were significantly less than those of the 0.7 and 0.5 mm groups. If E* < 1.0 unit were set as the imperceptible color change,20-22 it indicated that the luting composites could not produce a detectable color change in the veneers with 1.0 mm in thickness. Therefore, it is not necessary to investigate the color agreement of try-in pastes and the corresponding luting composites at a 1.0 mm thickness. For 0.7- or 0.5-mm thick veneers, two-way ANOVA results revealed that Epaste-luting values were significantly affected by the luting composite color and the thickness of veneer (p < 0.001, Table 3). All of the Epaste-luting values for 0.5 mm 310
Table 3 Two-way ANOVA results for the values of Epaste-luting
Veneer thickness (T) Luting composite color (L) T×L Error
Sum of squares
df
Mean square
F
p
1.147
2
0.573
32.771
Postgraduate Student, School and Hospital of Stomatology, Wuhan University, Wuhan, China Department of Prothodontics, Dalian Stomatological Hospital, Dalian, China 3 Professor, Director of Department of Prosthodontics, Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China 4 Associate Professor, Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China 2
Keywords Ceramic veneer; luting composite; try-in paste; color difference. Correspondence Yining Wang or Qing Li, Key Laboratory for Oral Biomedical Engineering of Ministry of Education, School and Hospital of Stomatology, Wuhan University, 237# Luoyu Road, Wuhan, China. E-mail: [email protected] or [email protected] ∗
These authors contributed equally to this study. Supported by the Fundamental Research Funds for the Central Universities (No. 201130402020002), China Postdoctoral Science Foundation funded project (No. 20100480870), National Natural Science Foundation of China (No. 81100784), and National Natural Science Foundation of China (No. 81070853).
Abstract Purpose: The aims of this study were to evaluate the influence of luting composites on the final color of ceramic veneers and to investigate the color matching of try-in pastes to the corresponding luting composites. Materials and Methods: Ceramic discs (shade A3, 1.0 mm thick) were fabricated and seated on composite specimens (shade A3) to mimic a complex of ceramic veneer lying on dentin substrate. The try-in pastes and luting composites of 3M RelyX were applied into the interlayer of the ceramic and composite specimens. The colors of the complexes were measured using a spectrophotometer, and subsequently converted to CIE L*a*b* values. Color changes after luting composites were applied, and the changes between the try-in pastes and the corresponding luting composites were calculated and registered as Eluting and Epaste-luting . Color measurements were repeated while the ceramic specimens were reduced to 0.7 mm and then 0.5 mm in thickness. Results: The means of Eluting were 0.69 ± 0.21, 1.27 ± 0.48, and 1.40 ± 0.57 for the 1.0, 0.7, and 0.5 mm thicknesses, respectively. Two-way ANOVA revealed that Epaste-luting values were significantly affected by the colors of luting composites and veneer thickness (p < 0.001). Lighter shades of luting composites showed less influence on Epaste-luting values. Conclusions: Luting composites could slightly modify the final color of ceramic veneers. Color matching of a try-in paste to the corresponding luting composite was not always achieved in the 0.7 or 0.5 mm thicknesses.
The authors deny any conflicts of interest. Accepted July 10, 2013 doi: 10.1111/jopr.12109
Esthetic dentistry attaches importance to the conservation of healthy tooth structure integrated with biologic and long-term functional requirements. Since the first published article on porcelain veneering,1 the ceramic laminate veneer has become a popular technique for improving the appearance of anterior teeth. This technique allows for less-aggressive tooth removal than full coverage restorations and demonstrates excellent clinical performance in terms of periodontal reaction and biocompatibility, which favor a healthy gingival response.2,3 To obtain a durable bonding strength for ceramic veneers, tooth reduction should remain within the enamel layer, which 308
is described as 0.7 to 0.8 mm thick.2 As a result, ceramic laminate veneers are ideally thin and relatively translucent. The color of tooth substrate or luting composites might potentially influence the final color of veneer restorations.4-6 It is essential to gain the approval of the patient before final cementation takes place.7 However, it is a challenge for dentists to predict the resultant color of ceramic veneers. Several approaches have been described to mask discolored tooth substrate and adjust the final appearance of the restorations. These approaches include the application of more opaque porcelain8 or the use of different colors of luting composites.9 An opaque ceramic layer will
C 2014 by the American College of Prosthodontists Journal of Prosthodontics 23 (2014) 308–312
Xu et al
compromise the esthetics of veneer restorations.2,10 Therefore, the application of different color luting composites seems to be a promising approach for adjusting the resultant color.11 Manufacturers have introduced several adhesive systems for ceramic veneers, including various colors of luting composites and the corresponding try-in pastes. They have claimed that the luting composites of various shades could be used to modify the final color of the veneers to attain color matching. The try-in pastes could be used as indicators of the final color and as a guide to choose an appropriate color of the luting composites; however, there is no agreement in the literature about the influence of the luting composites on the resultant color of ceramic veneers. Moreover, controversial viewpoints, concerned about the color agreement of try-in pastes and luting composites, have been proposed. ALGhazali et al noted the clinically significant color differences between a try-in paste and the luting composite of the same shade.12 On the other hand, high agreement of the try-in paste and the corresponding luting composite has also been reported.13,14 The purposes of this study were to evaluate the influence of the luting composites on the resultant color of ceramic veneers, and to investigate color agreement of try-in pastes to the corresponding luting composites. The null hypotheses were that there was no difference in the color of the final restorations achieved using various shades of luting composites, and there was no perceptible color difference between the try-in pastes and the corresponding luting composites.
Materials and methods Pressable lithium disilicate glass-ceramic discs (IPS e.max; Ivoclar, Schaan, Liechtenstein) and composite specimens (Amelogen Plus; Ultradent, South Jordan, UT) were fabricated to represent ceramic veneers and backgrounds with various colors. An adhesive system (RelyXTM Veneer; 3M ESPE, St. Paul, MN) with five shades of try-in pastes and luting composites (Translucent, B0.5, A1, A3, White Opaque) was included in the study (Table 1).
Fabrication of ceramic veneers and backgrounds
Disc-shaped ceramic specimens (nominal shade A3 to Vita Lumin, 10 mm in diameter) were fabricated by the lost-wax technique in accordance with the manufacturer’s instructions. Wet silicone carbide paper (600-, 800-, 1000-, 1500-grit) was used to polish the specimens and achieve a thickness of 1.0 ± 0.01 mm (n = 10) using a digital micrometer (Mitutoyo, Tokyo, Japan). Finally, a self-glazing process was performed at the manufacturer’s recommended temperature. No internal or external staining was used in the fabrication procedure. Composite discs (10 mm diameter, 4.0 mm thick, shade A3) were fabricated and served as the background colors to mimic the prepared dentin substrate. To avoid the color measurement errors caused by the mismatched position, notches were cut in the edge of each quarter of the specimens (Fig 1).
Validity of Try-In Paste as an Indicator for Veneer’s Color
Application of adhesive agents
The ceramic specimens were placed on the composite discs with notches matched. Try-in pastes or the corresponding luting composites were applied between the ceramic and composite specimens to build up the veneer/cement/background complexes. The complexes were registered as TP group (try-in paste) or LC group (luting composite) according to the adhesive agents applied. Complexes with a refractive liquid (with an index of refraction of 1.50) applied between the ceramic and background to achieve the optical connection15 served as the control group (baseline). Pressure (200 g) was applied on the top surface of the ceramic veneers for 10 seconds. Then 40 seconds of light curing was performed for the LC group. For the convenience of the separation from the composite background, the ceramic veneers were not acid etched, and no coupling agent was used. Color measurements
The color measurement apparatus consisted of a spectrophotometer (PR-650 Spectra Scan, equipped with MS-75 and SL0.5X lens; Photo Research, Chatsworth, GA) and two fiber optic light cables. The optic light cables, positioned at a 45◦ angle right-and-left to the spectrophotometer, provided an optical configuration of 0◦ observation and 45◦ illumination, recommended by Bolt et al for measuring the color of translucent materials.16 The spectrophotometer was standardized to 91.4 mm from the measured object with a measurement aperture size 1.5 mm in diameter. The standardized illumination source D65 (Model OL 53; Optronic Laboratories, Orlando, FL) and 2◦ observer configuration were used. For the color measurements, spectral reflectance was obtained from 380 to 780 nm (2 nm interval) and subsequently converted to the CIE L*a*b* values established by Commission International de L’Eclairage (CIE).17 Before each session of measurement, the spectrophotometer was calibrated with a white reflectance standard tile supplied by the manufacturer. A customized jig with a pointer was used to hold the specimens and confirm the position of the notches in the specimens (Fig 1). Color errors of 1-week repeated measurements using this instrumental measuring system were less than 0.027 per E unit.18 After each measurement, the veneer was separated from the composite background, and both of the veneers and the composite backgrounds were polished using 1500-grit silicone carbide paper to remove the adhesive layer. Then, an assembling procedure with another color of luting agents was performed. After the first session of color measurements, the veneers were decreased to 0.7 mm, and then 0.5 mm, in thickness. The color measurements were repeated. Statistical analysis
Color differences between the control and LC groups (registered as Eluting ), or between TP and LC groups (registered as Epaste-luting ) were determined by the equation: E = [(L*)2 + (a*)2 + (b*)2 ]1/2 .19 Color parameters L*, a*, and b* presented the differences in lightness, the green-red coordinate, and the blue-yellow coordinate, respectively. Two-way ANOVA was used to analyze the effects of veneer thickness and luting composite color on Epaste-luting values. Tukey’s post
C 2014 by the American College of Prosthodontists Journal of Prosthodontics 23 (2014) 308–312
309
Validity of Try-In Paste as an Indicator for Veneer’s Color
Xu et al
Table 1 All-ceramic veneer adhesive system used Materials TM
RelyX
Veneer
Shade
Code
Batch number
Manufacturer
Translucent B0.5 A1 A3 White opaque
TR B0.5 A1 A3 WO
8CU, 8FJ 8BY, 8CW 8CA, 8EF 8BX, 8CT 8CA, 8CX
3M ESPE, St. Paul, MN
Figure 1 Specimens on the positioning jig and color measuring system. (A) a: holder for specimens, b: ceramic veneer, c: pointer. (B) a: PR650 spectrophotometer, b: D65 light source, c: specimen on the jig.
Table 2 Means of Eluting values with different ceramic thickness Thickness 1.0 mm 0.7 mm 0.5 mm
n 50 50 50
Mean of Eluting (SD) Source
a
0.69 (0.21) 1.27 (0.48)b 1.40 (0.57)b
Different superscript letters indicate significant difference.
hoc comparisons were performed to evaluate the differences among various luting composite colors. SPSS statistical software (SPSS 13.0 for Windows, SPSS, Chicago, IL) was used for the analysis. The level of significance was established at α = 0.05.
Results The means of Eluting were 0.69 ± 0.21, 1.27 ± 0.48, and 1.40 ± 0.57 for 1.0, 0.7, and 0.5 mm thicknesses, respectively (Table 2). ANOVA results revealed that Eluting values in group 1.0 mm were significantly less than those of the 0.7 and 0.5 mm groups. If E* < 1.0 unit were set as the imperceptible color change,20-22 it indicated that the luting composites could not produce a detectable color change in the veneers with 1.0 mm in thickness. Therefore, it is not necessary to investigate the color agreement of try-in pastes and the corresponding luting composites at a 1.0 mm thickness. For 0.7- or 0.5-mm thick veneers, two-way ANOVA results revealed that Epaste-luting values were significantly affected by the luting composite color and the thickness of veneer (p < 0.001, Table 3). All of the Epaste-luting values for 0.5 mm 310
Table 3 Two-way ANOVA results for the values of Epaste-luting
Veneer thickness (T) Luting composite color (L) T×L Error
Sum of squares
df
Mean square
F
p
1.147
2
0.573
32.771
