Translucent Shades Research Articles

Evaluation of the Effect of Background Color on the Color Change of Composite Resins of Different Translucencies

Aim: To evaluate the effect of background color on the color change evaluation of composite resins of different translucency. Material and Method: In our study, Estelite ∑ Quick (EQ) CE, OA2 and Filtek Ultimate (FU) A2 Enamel, A2 Dentin composites were used. Disc-shaped samples were prepared from the composites of both brands by layering enamel and dentin alone and enamel + dentin (n=10). After preparation, samples were kept in distilled water for 24 hours and then in coloring solution (NescafeClassic) for 10 days. Colors of the composite samples were measured with a spectrophotometer (VıtaEasyshade) on black, white and gray backgrounds after 24 hours (initial) and after coloring. Color change value (ΔE00) was calculated using two measurement values for each background. Color change values of the same composites measured on different backgrounds were compared. Additionally, the ΔE00 values of different translucent tones from the same company were compared on different backgrounds. One-way ANOVA and Tukey's post-hoc tests were used for statistical analysis. (α=0.05). Results: When used layered with dentin, enamel composites consistently showed lower ΔE00 values than enamel composites alone (p<0.05). When comparing ΔE00 values of the same composite resin samples on different background colors, the ΔE00 values measured on black background were found to be higher only for FU enamel compared to the values measured on the other two backgrounds (p<0.05). When different translucent shades from the same company were compared on different backgrounds, the ΔE00 ranking was found to be enamel > dentin >/=mine + dentin for all backgrounds. Conclusion: Different backgrounds did not affect the color evaluation of samples containing an opaque composite resin, dentin composite; however, they did affect the color evaluation of FU enamel, which is a translucent composite resin. When translucent composite resins are layered with more opaque composite resins, more accurate color evaluation can be achieved.

Standardization of processing parameters and color of gels aiming to replace citric pectin by mesocarp flour or pectin of passion fruit

The processing of passion fruit generates a huge quantity of wastes, reaching 50% in mass of rind. The main use of the rinds is to produce rind flour or to be source of pectin as a gelling agent. This work develops a standard procedure to evaluate jelly products subjected to the same temperature histories and content of soluble solids along the processing time of the gel-based product, using different concentrations of mesocarp flour and pectin. The gels were evaluated by color patterns aiming to verify the applicability of mesocarp flour as substitute of commercial pectin in jelly of fruits. The quantitative analysis of the data for temperature histories and content of soluble solids enabled to confirm the standardization of the parameters used in the production of the gels, which is important to warrant the same processing conditions during the elaboration of the different types of gels. The gels made with passion fruit’s mesocarp flour have less translucent shades and a more yellowish color than the gels produced with commercial citric pectin, however, these small differences may not interfere in the final color of fruit jelly.

Thermocycling Stain Challenge and Colour Stability of two Current Zirconium Silicate-filled Indirect Composite Restorative Materials

Aim: This study compares the colour stability of two zirconium silicate-filled indirect composite materials CM and its improved formulation CMD using an in vitro thermocycling stain challenge model with 2 immersion solutions. The rationale of the thermocycling stain challenge model is to replicate the intraoral conditions that the indirect composite materials may be exposed to during a clinical service, water or saliva absorption and cyclical exposure to staining food colourant at varying temperature extremes. Materials and Methods: Ten discs each from shade A1 subtypes of CM and CMD indirect composites (Dentine Body A1B, Incisal 58, and Translucent HVT) were subjected to a thermocycling stain challenge following final polishing, which consisted of static immersion in 37°C of distilled water, followed by 500 thermocycles in 5°C of tea and 55°C of soy sauce and finally a 10-minute cleaning using an ultrasonic device. L*, a* and b* colour coordinates were measured, and the mean colour difference expressed as Delta E (ΔE) at different time points of the experiment were calculated and compared. Results: CM and CMD indirect composites had a significant color difference at all experimental time points (F=37.818, p<0.001). ΔE for CM subtypes and CMD subtypes in descending order, respectively, were Translucent HVT>Incisal 58>Dentin Body A1B and Incisal 58>Translucent HVT>Dentin Body A1B. Conclusion: CMD indirect composite showed improved colour stability compared to CM indirect composite. Clinical Significance: Limiting the usage of translucent shades and polishing according to the manufacturer’s recommendation may improve the overall colour of prostheses made using indirect zirconium silicate-filled composite materials.

"Enamel layering" using double-layered enamel-shade resin composites: The strategy to simulate the optical characteristics of human enamel.

To evaluate the optical match between enamel and resin composites fabricated using mono-layered and double-layered techniques. Enamel slabs were prepared from human upper incisors and canines. Mono-layered composite replicas were prepared from seven Filtek Z350XT and Estelite Sigma shades using silicone molds prepared from the respective enamel surfaces. Translucent and enamel shades (A2 or A3) of the two materials were produced from incisor molds for double-layered replicas, and the groups with the best results underwent accelerated aging. Spectrophotometric evaluation was performed using CIE color system. The differences in translucency (ΔTP) and color (ΔE00 ) between the enamel and paired composite replicas were calculated and analyzed using parametric statistics (α = 0.05). For the mono-layered composites, white enamel and translucent shades of Filtek yielded the lowest ΔTP for canines (4.6) and incisors (8.9), respectively. The ΔE00 of mono-layered replicas ranged from 5.1 to 11.8. Double-layered Filtek replicas displayed a better 1-day optical match with the lowest ΔTP (3.4-4.0) and ΔE00 (4.2-4.6), irrespective of each layer's thickness. For canines, the lowest ΔTP of Filtek white enamel was close to the acceptable threshold (4.43). For incisors, the thicker translucent double-layered Filtek composites demonstrated the greatest optical match before and after aging. Upper incisors and canines have distinct enamel optical properties. Enamel layering using specific double-layered resin composites could achieve a better optical match with upper incisor enamel.

Translucency and Radiopacity of Dental Resin Composites - Is There a Direct Relation?

The purpose of this study was to correlate the translucency degree of varying resin composites with their radiopacity. Twenty-four resin composites (conventional or bulk-fill) of various shades and opacities were selected from the following manufacturers: 3M ESPE (nanofilled), Ivoclar (nanohybrid), and FGM (microhybrid). Resin composite samples (n=5) were prepared (5-mm diameter × 1.5-mm thickness) for comparison using prepared samples of human dentin and enamel as controls. The translucency of each sample was measured using the translucent parameter (TP) method with a digital spectrophotometer (Vita Easyshade) and CIEL*a*b* color system over white and black backgrounds. The samples were also x-rayed using a photostimulable phosphor plate system for measurement of their radiopacity (in mmAl). All data were analyzed using one-way ANOVA and Student-Newman-Keuls (α=0.05); data for TP and radiopacity were correlated using the Spearman correlation test. Overall, the translucent shades and bulk-fill resin composites showed greater translucency than the other resins. While "body" and "enamel" shades demonstrated intermediate translucency to dentin and enamel, the "dentin" shades were more standardized, showing similar translucency to human dentin. All tested resin composites showed similar or greater radiopacity to human enamel, except the Empress Direct (Ivoclar) resin with Trans Opal shade, which was not radiopaque. Dentin and enamel showed radiopacity similar to 1 and 2 mmAl (millimeters of aluminum), respectively. The resin composites investigated in this study differed regarding their translucency degree and radiopacity level, without any positive relationship between the two properties.

Assessment of relative translucency and resultant color of contemporary resin-matrix ceramics indicated for laminate veneers and full crowns.

Evaluation of the optical properties of restorative materials is an important parameter for identifying clinical success. The aim of this study was to compare the translucency of contemporary resin-matrix ceramics (RMCs) and to evaluate the effect of cement shade on the final color of RMCs indicated for laminate veneers and full crowns. A hundred A2 shade RMC specimens were fabricated by using Mazic Duro (MD), CAMouflage NOW (CN), KZR-CAD HR2 (KZR), Grandio Block (GB), and Brilliant Crios (BC) at 0.7-mm and 1.5-mm thicknesses (n = 10). A2 shade composite resin was used for the foundation structure. Twenty resin-cement specimens were prepared from A2 and translucent shades at 0.1-mm thickness. Interchangeably, the foundation-cement-resin matrix ceramic assemblies were created with optical gel. The color coordinates were recorded using a spectrophotometer. After calculating translucency parameter (TP00) and color difference (ΔE00) values, data were analyzed statistically (P = 0.05). TP00 values were influenced by RMC type and thickness. TP00 values of RMCs can be listed in descending order as MD>GB = CN>BC=KZR. ΔE00 values were significantly influenced by all parameters and their interactions. MD exhibited higher ΔE00 values among tested RMCs. The effect of A2 cement was not perceived visually while TR cement demonstrated visually perceptible but clinically acceptable values for both laminate veneers and full crowns. As the material thickness decreased, the TP00 and ΔE00 values increased in all RMCs. Clinicians should carefully prefer cement shade and RMC material by contemplating their impact on the optical properties particularly when the restoration is thin.

Glass fiber posts relining: can composite opacity influence retention to root canal dentin?

This study aimed at evaluating the influence of glass-fiber post (GFP) relining with composites of different opacities on resin cement layer thickness (CLT), bond strength (BS) to root dentin, and resin cement degree of conversion (DC%). Standardized roots of 52 bovine incisors had their canals prepared and were distributed into 4 groups (n = 10 for CLT and BS; n = 3 for DC%) according to the post used: WP3 (Control)-Whitepost DC3; groups DE, EN and TR-Whitepost DC0.5 relined, respectively, with dentin, enamel, and translucent shade composites. After cementation, specimens were sectioned into six 1.0mm-thick discs that were submitted to push-out BS test. CLT and failure pattern were evaluated using a stereomicroscope and DC% by micro-Raman spectroscopy. Data were analyzed by two-way ANOVA and Tukey test (α = 0.05). The control group showed greater CLT than all relined groups (p < 0.05), which did not differ from each other (p > 0.05). Groups relined with low opacity composites (TR; EN) showed the highest BS and DC% means (p < 0.05). BS was not different among root thirds (p > 0.05), while DC% decreased from cervical to apical third (p < 0.05). Adhesive failures between cement and dentin were predominant, except for group DE with frequent mixed failures. It could be concluded that composite opacity did not influence CLT, which was thinner when GFP were relined and that relining GFP with lower opacity composites led to higher BS and DC%.

Assessment of control strategy of adaptive façades for heating, cooling, lighting energy conservation and glare prevention

A movable shading device installed on an adaptive façade is able to change the positions of the shades according to the various control objectives (i.e. daylighting, thermal comfort, glare, energy, etc.) of the occupant. Since the key variables and the control method may change according to the control objectives, it is important to determine the hourly states of the shades in consideration of all of these factors. This study proposes a multi-purposes control strategy of adaptive facades for heating, cooling, lighting energy and glare. To depict the movements of the movable shading devices, the operable range is represented by an n number of fixed shade states having constant intervals. The control strategy entails deriving allowable shade states for glare prevention and energy conservation independently and then deriving the intersection range between the two shade state ranges. A case study was performed to verify the changes in hourly shade states and the energy performance of the envelope obtained by applying the proposed control strategy to an adaptive façade having a movable folding type shading device. The results of the case study show that hourly shade states were determined to satisfy the objectives of glare prevention and energy conservation simultaneously based on weather conditions and indoor requirement settings. From the case study, it can be seen that the proposed method can block the entry of direct solar radiation by lowering the unshaded fraction according to whether or not there would be discomfort glare while increasing the view factor in certain sections to promote the entry of diffuse solar radiation into the indoor space during the cooling and heating periods. The results of the case study also show that there can be large differences in the heating, cooling, and lighting energy performance of the building envelope for each orientation depending on the order of priority given to the objectives of the shading control, i.e. the objective of energy conservation only and the objective of simultaneous glare prevention and energy conservation. However, it was possible to effectively reduce the differences in energy proportions by adopting translucent shades.

Translucency of Cad/Cam Veneers Using Different Internal Relief Spaces and Luting Cement Shades

Statement of Problem: Many studies have investigated translucency of ceramic veneers in association with different trial insertion paste materials.1,2,3. Little information is available on the ef- fect of cement space thickness on the final shade color of glass ceramic, feldspathic and zirconia reinforced glass ceramic veneers. Purpose: The aim of the study is to evaluate translucency of three different CAD/CAM ve- neer materials with different internal relief spaces and different cement shades. Material and Method: Sixty samples were constructed and classified according to the type of materials into three main groups ( I ) IPS e.max CAD MT , ( II ) VITA Vitablocs Mark II and group ( III ) Vita Suprinity (20 samples each). Each group were subdivided into two subgroups (10 samples each) according to the internal relief space (100 µm and 30 µm).The internal relief space was determined based on data from a previous 123 study and available resources. Each subgroup were further subdivided into six classes according to the 4 type of trial cements used : the control class ( glycerine ) and five trial paste class- es according to their shade (Translucent Shade, White Opaque Shade, A1/Light Yellow Shade, A3 Opaque/Yellow Opaque Shade and B0.5/ White Shade (10 sam- ples each) according to shade of the trial cement used. The color test was done using reflectance spectrophotometer device ( Vita Easy shade V). Color coordinates were measured in the body region of all laminate ve- neers with different combinations of laminate veneer material, internal relief space, and trial insertion paste color on composite resin abutment A3 . Results: The consistency of the translucency among the tested specimens was confirmed using a 2-way ANOVA and the Tukey HSD post hoc test (P&lt;.05). The luminous transmittance exhibited a statistically significant dependence on different ceramic restorations with a cad cam veneers in various internal relief space and different cement shades combinations. (P&lt;.05). Conclusions: The underlying color of the tested trial insertion pastes caused color change (?E &gt;3.7) for all ceramic material used in this study.

Effect of Surface Treatments on the Color Change and Shear Bond Strength of Porcelain Laminate Veneer

Effect of Surface Treatments on the Color Change and Shear Bond Strength of Porcelain Laminate Veneer Aim of the study: the purpose of this Invitro study to evaluate the effect of surface treatments on the color change and shear bond strength of lithium disilicate glass ceramic veneers. Materials & Methods: Twenty square samples with dimensions (8x8x2) and another twenty samples with smaller dimensions (4x4x2) were cut from five IPS e-max CAD blocks of shade A3. The discs were divided into two groups: 1) Half of the small and large blocks were subjected to hydrofluoric acid (HF); 2) the other half was subjected to Co2 laser irradiation. The conditioned samples were subdivided according to the bonding agent: A) Silane application for 60 seconds; B) Single bond universal light cured for 10 seconds. Each small sample was cemented on the top of a large sample using Rely-x veneer cement with translucent shade. The color change was measured using spectrophotometer. The shear bond strength was tested using a universal testing machine. Results: HF resulted in higher bond shear bond strength and ΔE than Co2 laser. Single bond universal resulted in higher shear bond strength values than silane. Conclusion: HF followed by either single bond universal or silane could be the best surface treatment for e-max CAD ceramic. However, Co2 laser could be a promising alternative surface treatment.

Gevo announces breakthrough development of renewable isoprene, a key chemical building block for producing rubber and rubber products

A movable shading device installed on an adaptive façade is able to change the positions of the shades according to the various control objectives (i.e. daylighting, thermal comfort, glare, energy, etc.) of the occupant. Since the key variables and the control method may change according to the control objectives, it is important to determine the hourly states of the shades in consideration of all of these factors. This study proposes a multi-purposes control strategy of adaptive facades for heating, cooling, lighting energy and glare. To depict the movements of the movable shading devices, the operable range is represented by an n number of fixed shade states having constant intervals. The control strategy entails deriving allowable shade states for glare prevention and energy conservation independently and then deriving the intersection range between the two shade state ranges. A case study was performed to verify the changes in hourly shade states and the energy performance of the envelope obtained by applying the proposed control strategy to an adaptive façade having a movable folding type shading device. The results of the case study show that hourly shade states were determined to satisfy the objectives of glare prevention and energy conservation simultaneously based on weather conditions and indoor requirement settings. From the case study, it can be seen that the proposed method can block the entry of direct solar radiation by lowering the unshaded fraction according to whether or not there would be discomfort glare while increasing the view factor in certain sections to promote the entry of diffuse solar radiation into the indoor space during the cooling and heating periods. The results of the case study also show that there can be large differences in the heating, cooling, and lighting energy performance of the building envelope for each orientation depending on the order of priority given to the objectives of the shading control, i.e. the objective of energy conservation only and the objective of simultaneous glare prevention and energy conservation. However, it was possible to effectively reduce the differences in energy proportions by adopting translucent shades.

The influence of different shades and brands of resin-based luting agents on the final color of leucite-reinforced veneering ceramic

ObjectivesThis study aimed to evaluate the influence of different shades and brands of resin-based luting agents on the final color of a leucite-reinforced veneering ceramic. MethodsThis in-vitro study was done on 36 ceramic discs (IPS Empress I, 11 × 0.5 mm, A2 shade) and 36 cement disks (11 × 0.2 mm) made of Panavia SA Cement Plus (Kuraray Medical Inc.) and Choice2 (Bisco Inc., Schumburg) brands in translucent, universal A2, and opaque shades (n = 6 per each color in each resin cement brand). Color parameters (CIEL*a*b*) of ceramic specimens were calculated without and with each brand/shade of resin-based luting agents by using a spectrophotometer, and put into CIELab formula. The color differences (ΔE) between the two sets of measurements were calculated and analyzed with two-way ANOVA and Tukey’s post hoc test (α = 0.05). ResultsBoth the resin-based luting agent shade (P < 0.001) and brand (P = 0.023) significantly affected the color differences. ΔE values were significantly different between Panavia-opaque and Choice2-opaque (P < 0.001). No significant difference existed between ΔE of the two brands in A2 (P = 0.178) and translucent shades (P = 0.079). The ΔE values of Panavia-A2 was significantly different from the translucent and opaque shades of the same brand. Moreover, the ΔE of Choice2-translucent shade was significantly lower than that of A2 and opaque shades. The ΔE values were higher than the clinically-acceptable threshold in all groups (ΔE > 3.7) except for Choice2-translucent (ΔE = 3.37). ConclusionsThe final color of leucite-reinforced veneering ceramic can be affected by the same shades of resin-based luting agents from different brands and different shades of resin-based luting agents from the same brand.

The translucency effect of different colored resin cements used with zirconia core and titanium abutments.

The purpose of this study was to evaluate the effect of the different color of resin cements and zirconia cores on the translucency parameter (TP) of the restoration that simulates the implant-supported fixed prosthesis using titanium base on the bottom. Zirconia core plates (Zr-Zahn) were prepared in A2 shades (n = 11). Resin cement plates (3M ESPE) were prepared in A2, A1, translucent (TR) shades (n = 11). The initial color measurements and were measured on zirconia core plates, and resin cements plates using a spectrophotometer. Then, the resin cement plates were placed below the zirconia core plates, and the second measurements were done. The final measurements were done after placing the titanium discs in the bottom. The data were analyzed with two-way analysis of variance and Tukey honestly significant differences tests (α = 0.05). The highest TP values were recorded for A1-colored resin specimens and the lowest for zirconia core plates in the first measurement (P < 0.05). The addition of zirconia core decreased the TP values in all tested resin cement groups (P < 0.05). The highest TP value was recorded for A1-colored resin cement with zirconia core plates and the lowest for A2 and TR with zirconia core plates after second measurements (P < 0.05). The addition of titanium decreased the TP of the zirconia core plate and resin cement combination (P < 0.05). The addition of a zirconia core under the resin cement dramatically reduced the TP values, and the presence of a titanium layer decreased the TP value and caused a darker appearance.

The Effect of Artificial Accelerated Aging on the Color of Ceramic Veneers Cemented with Different Resin Cements : A Comparative in Vitro Study

ABSTRACT Background: Color changes that are detectable to human eye can affect the esthetic appearance of ceramic veneers. The purpose of this study was to evaluate and compare the effect of artificial accelerated aging on the color of ceramic veneers cemented with different resin cements. Materials and Methods: Sixty discs were prepared with 0.5 mm thickness, 30 discs made from IPS e.max press (Ivoclar Vivadent) and 30 discs were made from VITA Enamic (VITA Zahnfabrik). The discs were cemented with three resin cements: Variolink Veneer MV 0 shade (Ivoclar Vivadent), Rely X veneer Translucent shade (3M ESPE) and NX3 Nexus Clear shade (Kerr Corporation) with 0.1 mm thickness. The spectrophotometer Easyshade Advance was used to measure the color parameters (Lightness, axis a* of chroma and axis b*of chroma) immediately after cementation, after 150 and 300 hours of aging. The specimens were subjected to artificial accelerated aging in Accelerated Weathering Tester. Color change greater than 3.3 was considered unacceptable. One-way ANOVA, paired t-tests and Bonferroni adjusted t-test were used for statistical analysis (p

SPECTROPHOTOMETRIC ANALYSIS OF DISCOLORED ANTERIOR TEETH RESTORED WITH PREFAPRICATED COMPOSITE RESIN VENEERS

INTRODUCTION: Veneers are considered the least invasive most reliable solution for treatment of discolored anterior teeth. Edelweiss system is a polymerized, prefabricated, laser-machined, radiopaque, highly-filled nano-hybrid composite enamel shells with a highly glossy inorganic surface. They have a facial anatomical pattern in the shape of a thin composite shell bonded to labial surface of anterior teeth with composite resin, which allows for easy direct veneering of single and multiple anterior teeth.OBJECTIVES Spectrophotometric analysis of discolored anterior teeth restored with Edelweiss veneer system bonded with different shades of composite resin.MATERIALS AND METHODS: Twenty Edelweiss veneers bonded with different shades of composite resin (A2, opaque white and translucent shades) to dies of different shades. Specimens were divided into four groups, each group consists of five specimens, according to the shade of the bonding composite resin used and the shade of the dies. Spectrophotometer was used to evaluate the effect of using different shades of the bonding composite on the final shade of the restoration. Also, to assess the light reflection, transmission and absorption of the Edelweiss Veneer System.RESULTS: The L*a*b* coordinates values of the Edelweiss Veneer Systems were affected by the shade of bonding composite (P<0.05). The use of an opaque bonding composite resulted in an increase of the color coordinates a*, b*, L*, producing the greatest effect on color change, light transmission and light reflection (P<0.05). Light absorption values of the specimens were not affected by the shade of the bonding composite. CONCLUSIONS: On using Edelweiss veneer system, the greatest color shifts and change in light transmission and light reflection were obtained when using opaque shade composite for bonding of the veneers to the substrates. While light absorption was of a non-significant value among the groups.

Relevant optical properties for direct restorative materials

ObjectivesTo evaluate relevant optical properties of esthetic direct restorative materials focusing on whitened and translucent shades. MethodsEnamel (E), body (B), dentin (D), translucent (T) and whitened (Wh) shades for E (WhE) and B (WhB) from a restorative system (Filtek Supreme XTE, 3M ESPE) were evaluated. Samples (1mm thick) were prepared. Spectral reflectance (R%) and color coordinates (L*, a*, b*, C* and h°) were measured against black and white backgrounds, using a spectroradiometer, in a viewing booth, with CIE D65 illuminant and d/0° geometry. Scattering (S) and absorption (K) coefficients and transmittance (T%) were calculated using Kubelka–Munk's equations. Translucency (TP) and opalescence (OP) parameters and whiteness index (W*) were obtained from differences of CIELAB color coordinates. R%, S, K and T% curves from all shades were compared using VAF (Variance Accounting For) coefficient with Cauchy–Schwarz inequality. Color coordinates and optical parameters were statistically analyzed using one-way ANOVA, Tukey's test with Bonferroni correction (α=0.0007). ResultsSpectral behavior of R% and S were different for T shades. In addition, T shades showed the lowest R%, S and K values, as well as the highest T%, TP an OP values. In most cases, WhB shades showed different color and optical properties (including TP and W*) than their corresponding B shades. WhE shades showed similar mean W* values and higher mean T% and TP values than E shades. SignificanceWhen using whitened or translucent composites, the final color is influenced not only by the intraoral background but also by the color and optical properties of multilayers used in the esthetic restoration.

Energy Saving Effects of Sidelighting Strategy

In a daylighted space, windows can introduce considerable heat gain and loss that may offset the benefits of electric light savings and cause an increase in yearly net energy use. The use of shading devices is necessary to prevent overheating and provide a glare-free visual environment. The common shading devices that have been in use in buildings are exterior overhangs, interior blinds and roller shades. This study examines the impacts of an exterior louvered overhang, translucent roller shade, and blinds on the total yearly energy loads for a prototypical classroom space situated in Boulder, Colorado. Coordinated modeling, with an advanced daylight and electric lighting simulation program and a building thermal simulation program based on hourly weather data, was used to compute total yearly building energy use. Annual lighting, cooling and heating loads for a side-lit space using these shading devices were compared with those of a base case with no shading device. It was found that the total energy performance of the roller shade with a total transmittance of 10.4% was similar to blinds tilted 45o with 60% reflectance. The roller shade consumed 12.5% more total building energy than exterior 1.2m overhang.

Do surface treatments affect the optical properties of ceramic veneers?

Surface treatments may affect the optical properties of ceramic veneers before cementation. The purpose of this study was to evaluate whether various surface treatments affect the optical properties of different types of ceramic veneers. Disk-shaped ceramic veneers (N=280) were prepared from the IPS e.max Press, e.max CAD, Empress Esthetic, e.max Ceram, and Inline ceramic systems with 0.5-mm and 1.0-mm thicknesses. The ceramics were divided into 4 groups: no surface treatments; etched with hydrofluoric acid; airborne-particle abraded with 30-μm Al2O3; and irradiated with erbium:yttrium-aluminum-garnet laser. A translucent shade of resin was chosen for cementation. Color parameters were examined with a colorimeter. Statistical analyses were done with 3-way ANOVA and the Bonferroni test (P=.05). Significant interactions were noted between the surface treatments, ceramic type, and thickness for ΔE values (P=.01), and no significant interactions were noted for L* (P=.773), a* (P=.984), and b* (P=.998). The greatest color change occurred after airborne-particle abrasion with 0.5-mm-thick e.max Press (2.9 ΔE). Significant differences in ΔE values were found among the hydrofluoric acid, airborne-particle abrasion, and laser groups for 0.5-mm-thick ceramics, except IPS Inline, and among the hydrofluoric acid, airborne-particle abrasion, and laser groups for 1.0-mm-thick ceramics, except Empress Esthetic ceramics. The color change of the ceramics increased after the surface treatments, particularly as the ceramics became thinner.

The influence of varying layer thicknesses on the color predictability of two different composite layering concepts

ObjectiveOptical properties of teeth are mimicked by composite layering techniques by combining a relatively opaque layer (dentin) with more translucent layers (enamel). However, the replacing material cannot always optically imitate the tooth when applied in the same thickness as that of the natural tissues. The natural layering composite system is available in 2 concepts: (1) dentin (D) and enamel (E) have the same shade but with different translucencies; (2) D and E have different shades where E is always the same high translucent shade. The objective was to evaluate the influence of varying thicknesses of E and D composites on the overall color and on the translucency for both concepts. MethodsFor each concept three composite brands were tested; Concept 1: Clearfil Photo Bright (Kuraray), Herculite XRV Ultra (Kerr), Venus Diamond (Heraeus Kulzer); Concept 2: Amaris (VOCO), CeramX Duo (DENTSPLY) and Point4 (Kerr). Two specimens of each shade (A1–A3) per composite were made of standardized thicknesses with a poly-acrylic mold and Teflon cover, making 36 specimens of wedge-like dimension. The L*a*b* values were measured three times against a white and black background (n=216). Student's t-tests revealed significant levels between the average ΔE* values of the 3 areas for each composite. ResultsStatistically significant differences (p<0.05) were found for all thicknesses and for all shades between the concepts. Concept 2 showed greater variations in ΔE* with increased thicknesses. SignificanceConcept 2 composites are more sensitive to layer thickness changes, which implicates less predictability in a daily clinical routine.

How will surface treatments affect the translucency of porcelain laminate veneers?

PURPOSEThe purpose of this study was to evaluate whether surface treatments affect the translucency of laminate veneers with different shades and thicknesses.MATERIALS AND METHODSA total of 224 disc-shaped ceramic veneers were prepared from A1, A3, HT (High Translucent) and HO (High Opaque) shades of IPS e.max Press (Ivoclar Vivadent) with 0.5 mm and 1.0 mm thicknesses. The ceramics were divided into four groups for surface treatments. Group C: no surface treatments; Group HF: etched with hydrofluoric acid; Group SB: sandblasted with 50-µm Al2O3; and Group L; irradiated with an Er;YAG laser. A translucent shade of resin cement (Rely X Veneer, 3M ESPE) was chosen for cementation. The color values of the veneers were measured with a colorimeter and translucency parameter (TP) values were calculated. A three-way ANOVA with interactions for TP values was performed and Bonferroni tests were used when appropriate (α=0.05).RESULTSThere were significant interactions between the surface treatments, ceramic shades and thicknesses (P=.001). For the 0.5-mm-thick specimens there were significant differences after the SB and L treatments. There was no significant difference between the HF and C treatments for any shades or thicknesses (P>.05). For the 1-mm-thick ceramics, there was only a significant difference between the L and C treatments for the HT shade ceramics (P=.01). There were also significant differences between the SB and C treatments except not for the HO shades (P=.768).CONCLUSIONThe SB and L treatments caused laminate veneers to become more opaque; however, HF treatment did not affect the TP values. When the laminate veneers were thinner, both the shade of the ceramic and the SB and laser treatments had a greater effect on the TP values.