Effect Of Translucency Research Articles

Masking ability of CAD-CAM resin-matrix ceramics with different translucencies and thicknesses combined with four cement shades against varying background colors when facing veneer restorations

BackgroundTo evaluate the comprehensive effect of translucency, thickness, cement shades, and background color on the masking ability of resin-matrix ceramic veneer restorations.MethodsResin-matrix ceramic specimens with 2 translucencies (LT, HT) and 3 thicknesses (0.5, 1.0, and 1.5 mm) were made of Upcera Hyramic (A2 shade). Cement specimens were made of Variolink N in 4 shades (yellow, white, transparent, and bleach XL). Five background specimens were made of IPS Natural Die Material in 5 shades (ND1, ND2, ND3, ND4, and ND5). Color coordinates of 120 subgroups (n = 5) of combined specimens composed of different ceramic, cement, and background specimens were obtained using a spectroradiometer. Color difference (ΔE00) compared with a 4-mm thick specimen of LT and HT ceramics was calculated and four-way ANOVA was used for statistical analysis (α = 0.05).ResultsTranslucency, thickness, cement shade, background color, and their interaction had significant effects on ΔE00 (p < 0.001). ΔE00 values of HT groups were always higher than that of LT groups and were greater than 1.8 against all background colors. ΔE00 values of LT groups could be achieved to be less than 1.8 with appropriate thickness and cement shade. ΔE00 value decreased with increasing ceramic thickness. The effect of cement shade on ΔE00 had no obvious regularity, but ΔE00 values of bleach XL cement shade group were always lower than other cement shade groups under ND3 and ND5 background color.ConclusionsThe masking ability of CAD-CAM resin-matrix ceramics can be simultaneously affected by translucency, thickness, cement shade, and background color. Resin-matrix ceramics with low translucency has a better masking ability than that with high translucency. The masking ability of CAD-CAM resin-matrix ceramics increase with increasing thickness. Cement shade has less impact on the final color of resin-matrix ceramic restorations.

Efficient Photon Beam Diffusion for Directional Subsurface Scattering.

Real-time subsurface scattering techniques are widely used in translucent material rendering. Among advanced methods that rely on the bidirectional scattering-surface reflectance distribution function (BSSRDF), screen space algorithms exhibit limited translucency, while existing large-distance methods are inefficient and yield poor illumination details. To address these limitations for better large-distance scattering, we develop a novel algorithm by extending the photon beam diffusion (PBD) model within the light view and screen space. Unlike surface irradiance in prior methods, we incorporate the refracted beam in the medium into real-time scattering estimation, presenting a new consideration for photon beam utilization. Concretely, we store all photon beam samples in light view textures and utilize an adaptive sampling pattern for beam sample selection in large filtering kernel sizes. This can reduce the sample count based on surface attributes. In screen space, virtual sources are derived from samples to estimate PBD contributions, with an approximation that preserves boundary conditions. To avoid possible overestimation, we implement correction factors that scale contributions, effectively aligning our results with path-tracing references. Through these reformulations, our efficient PBD generates results closest to references among existing methods. The experiments accurately represent better front-face illumination details and backlit translucency effects, while significantly accelerating performance compared to previous large-distance methods.

Translucency and colour masking ability of hybrid CAD/CAM materials with different thicknesses: in vitro study

ObjectiveTo evaluate effect of material thickness and translucency of two different hybrid CAD/CAM materials on their masking ability.Materials and Methods40 rectangular-shaped specimens (12 × 14 mm) were obtained from Vita Enamic and Grandio blocks at 0.5 and 1 mm-thick (n = 10/group). Colour parameters of specimens were measured on PMMA tooth-coloured replica backgrounds (A2, C4) and black, white backings using dental spectrophotometer. Translucency parameter (TP) and masking ability (∆E00) values of tested materials with 0.5, and 1 mm thicknesses were calculated. Quantitative variables were compared between groups using student t-test.ResultsTP and ∆E00 significantly decreased as thickness of tested materials increased. Grandio showed significantly higher TP values. There were significantly lower ΔE00 values for Vita Enamic compared to Grandio at 1 mm thickness and inversely insignificant at 0.5 mm. The 0.5 mm-thick ∆E00 of tested materials was above clinical acceptability threshold, whereas, 1 mm-thick did not exceed showing better masking properties.ConclusionsThickness is more effective for colour masking than translucency. In thin thickness, the masking ability is less effective, irrespective of tested materials. Translucency of tested materials was affected by their composition. Both hybrid CAD/CAM materials are promising alternatives for masking dark discolouration at 1 mm-thick.

Effect of Cement Translucency and Ceramic Thickness on the Resulting Colour Match of Zirconia-Reinforced Lithium Silicate Restorations Cemented over Dark-Coloured Substrate

Effect of Cement Translucency and Ceramic Thickness on the Resulting Colour Match of Zirconia-Reinforced Lithium Silicate Restorations Cemented over Dark-Coloured Substrate

Light Polymerization through Glass-ceramics: Influence of Light-polymerizing Unit's Emitted Power and Restoration Parameters (Shade, Translucency, and Thickness) on Transmitted Radiant Power.

This in vitro study assessed light transmission through ceramic discs varying in shade, translucency, and thickness using light-polymerizing units with different radiant power/flux (RP) outputs. Disc-shaped specimens (0.5 mm, 1.0 mm, and 2.0 mm) were made from high and low-translucency glass-ceramic ingots (IPS e.max Press) in shades A1 and A4, totaling 60 discs. Two light-polymerizing units with different power outputs were used, and their emission spectra were verified. The transmitted RP values for each ceramic specimen were measured and irradiance and radiant energy influx were calculated. Differences between the light-polymerizing units and the influence of the three ceramic parameters were evaluated using an independent-samples t-test and three-way analysis of variance (ANOVA) tests (α = 0.05). A statistically significant difference was observed in the mean transmitted RP values between the two light-polymerizing units. Furthermore, the three-way ANOVA test showed a significant effect of shade, translucency, and thickness, as well as a significant interaction between each pair of variables and all three variables on the transmitted RP (P < 0.05). Despite the significant attenuation in the transmitted RP, especially in ceramics with higher shade chromaticity and thickness and lower translucency, the calculated minimal irradiance values for both light-polymerizing units (their emitted power ≥ 500 mW) were greater than the minimum recommended irradiance threshold (100 mW/cm2). However, the exposure duration needs to be increased to provide the resin with sufficient radiant exposure for adequate polymerization.

Poster Session II: Image features involved in translucency enhancement by chromaticity information.

Previous studies have reported that chromaticity information in object images enhances perceived translucency. The aim of this study, was to elucidate how color forms image features that contribute to translucency in psychophysical experiments. The stimuli were computer-graphics images of translucent objects with different spectral scattering coefficients (i.e., hues) and various optical and geometrical parameters. Achromatic images with the same luminance as the chromatic images were also created. Perceived translucency was measured using Thurston's pairwise comparison, and the effect of chromaticity or translucency was evaluated by comparing translucency in achromatic and chromatic images. The results showed higher perceived translucency for the chromatic object images than the achromatic ones. Subsequently, we analyzed how different image features correlate with the effects of color on translucency using multiple regression analysis. The result indicated that the luminance- chromaticity correlation, which has been proposed as a potential cue for translucency could hardly explain the color effects. Rather, we found that the change in brightness contrast in the diffuse components modulated by the Helmholtz-Kohlrausch (H-K) effect was strongly and negatively correlated with the color effects. These results suggest that some image features, which covary with brightness contrast brightness contrast, contribute to the color effects on translucency.

PREVENTION OF RODENT ATTACK ON TERTIARY PACKAGE AT STORAGE LEVEL

Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Theses packaging are done at three levels they are namely primary, secondary and tertiary. Tertiary packaging is a type of wrapping which protects the manufactured products. It is used to smooth the progress of the transport and safe handling of goods. The synthetic polymer is best suitable for packaging as they are having good strength properties. It is selected for packaging application based on their grade of suitability and recyclability towards product. The production of film for tertiary pack at storage level is mainly focused on availability and process capabilities. The problem mostly arises in the case of tertiary packaging sector where the goods are packed and stored at warehouse. The synthesis of film was carried out by blending linear low density polyethylene and essential oil as a plasticizer through solvent casting method. The synthesis is accomplished by formulating the elements certain percentage toproduce film suitable for packaging. Thereafter testing was carried out and found that elongation has improvedfor LLDPE blends at a rate of 65.6% than LLDPE. The tensile strength was found to be reduced in LLDPE blends with value of 1.60Mpa. The contact angle was measured and it was found that the LLDPE film produce hydrophobicity than LLDPE with an increase of 3%. The UV spectroscopy was also measured and it was found that LLDPE blend film gave a translucent effect. The rodent test was also carried out and LLDPE film tends to repel them. Thus the LLDPE blends are made suitable for tertiary package.

Effect of Thickness and Translucency on Color Change and Masking Ability of Ceramic Materials used for Laminate Veneers.

This study evaluated the effect of the thickness and translucency of lithium disilicatebased glass ceramics on resin composite substrates on color change and masking effect. Laminate veneers were fabricated using IPS e.max CAD (A1) blocks with two different light transmittance values (High translucent [HT], Low translucent [LT]). Slices of two different thicknesses (0.3 mm, 0.5 mm) were obtained (n=10) and laminate veneers were cemented on the resin composite substrates of two different shades (A2, A3.5). The color change (ΔE values) was evaluated with the CIELab color system using a spectrophotometer, while the masking effect was calculated. The data were analyzed using independent-samples t-test and two-way analysis of variance. The ceramic thickness and translucency had a significant effect on final color and masking. When HT was used, and the laminate veneer thickness decreased (0.3 mm), the masking effect in ΔE values were lower (p⟨0.05). The ΔE values (⟩3.7) were clinically unacceptable. With the increase in thickness, translucency of porcelain laminate veneers decreases showing better color masking ability. Veneer thickness seems to be more effective on the restoration's masking ability than the shade of the substrate and translucency. Cinically, in case a 0.5-mm or thinner laminate veneer is planned, tooth color, resin cement and ceramic type should be considered.

Effect of translucency and absorbance of composite on temperature change during photopolymerization.

This study investigated the effect of translucency and absorbance of conventional (FiltekTM-Z350-XT) and bulk-fill (Tetric®-N-Ceram) composites on temperature change during photopolymerization, using a non-contact infrared sensor. Three shades from each composite were selected to prepare disk-shaped specimens (n=3), which then photopolymerized with LED-light for 20 s. A second light exposure was performed on the photopolymerized specimens. The first peak temperature rise during composite photopolymerization (ΔTtotal), second peak temperature rise by the light (ΔTlight), and net peak temperature rise by composite curing heat (ΔTcomposite) were obtained from the temperature change vs. time curve. The changes in ΔTtotal and ΔTlight with varying the composite shade were greater than those in ΔTcomposite. The conventional composite showed higher ΔTtotal and ΔTlight than bulk-fill composite. ΔTtotal and ΔTlight increased as translucency parameter decreased, and absorbance increased. The potential risk for heat-induced pulpal damage should be considered when selecting a composite shade, especially for deep cavities.

Novel translucent hollow fiber polyvinylidene fluoride photocatalytic membrane for highly efficient oil-produced wastewater treatment: The role of translucency on degradation efficiency

A novel method, Thermally Modified Non-Solvent Induced Phase Separation (T-NIPS) has been developed to fabricate translucent hollow fiber (THF) photocatalytic membrane for membrane’s photodegradation efficiency enhancement. The process involves two-step temperature treatment that attacks crystalline property of polyvinylidene fluoride (PVDF). Graphitic carbon nitride in a modified morphological structure (hollow nanofiber) was used as photocatalyst to investigate the effect of translucency on membrane’s photodegradation efficiency. UV-Vis analysis coupled with FTIR highlighted different crystalline phase appearance and membrane’s translucency. The membranes showed high translucency, ranging from 60.0% to 93.9%, with THF-PVDF/PVP-GCN (2.0) exhibiting the highest. The filtration experiment showed that membrane with GCN photocatalyst had high PWF (1200 L/m2h) and rejection (90%) OPW compared to neat THF-PVDFs. In suspended mode, GCN demonstrated an impressive photodegradation efficiency of 99.98%. When immobilized in opaque PVDF membrane, the photodegradation has decreased substantially to 49.40%. However, when immobilized in a translucent PVDF membrane, the photodegradation efficiency of HN-GCN significantly improved compared to the opaque PVDF membrane, reaching 95%. Translucent membrane was subjected to five cycle regeneration test and showed 90% recovery even after the fifth cycle. The 10% reduction in the recovery was investigated using FESEM analysis revealed that there is a cake layer formation on the membrane surface. Therefore, this study proved that translucency of membrane has significant effect on immobilized photocatalyst’s photocatalytic efficiency.

Effect of translucency and eggshell color on broiler breeder egg hatchability and hatch chick weight

A successful hatch has a considerable economic impact on all poultry companies. The aim of the current study was to describe the possible effects of shell translucency (T score) and coloration lightness (L* value) on shell thickness, hatchability, and chick weight. A total of 4,320 eggs from 4 commercial Ross 708 breeder flocks (50-55-wk old) were used. Eggs were selected for T score and L* value. A 3-point subjective scoring system was used for T score (1=low, 2=medium, 3=high), and an electronic colorimeter for L* value, sorting the eggs as light (avg. L*=80.7) or dark (avg. L*=76.0). Data were analyzed using the GLIMMIX procedure of SAS (V9.4) and Tukey's HSD test was performed to separate means, a significant difference was considered when P ≤ 0.05. Results suggest that the color of the eggshell was related to the egg weight on the day of collection (P=0.0056) and at transfer (P=0.0211), in both cases dark eggs were 0.6 g heavier than light eggs. Dark eggs had a 3.8% increased hatchability of egg set (P=0.0481) and yielded 6 µm thicker shells (P=0.0019) when compared to light eggs. Regarding translucency, egg weight at transfer was 0.8 g heavier for T score 1 eggs compared to T score 3 (P=0.0358). The translucency score of 1 had a 6.9% higher hatchability of eggs set (P=0.0127) and 0.7 g heavier chick weight (P=0.0385) compared to T score 3. However, T score 1 eggs had shells 28 µm thinner than the T score 2 and 34 µm thinner than T score 3 (P < 0.0001). An interaction effect was observed for eggshell thickness, L* value, and T score, where eggs classified as light with T score 1 had thinner eggshells compared to those that were dark with T score 3 (P=0.0292). These results suggest that eggshell translucency and coloration lightness can be good noninvasive indicators of eggshell thickness, hatchability, and chick weight in broiler breeder flocks.

Effect of thickness, translucency, and substrates on the masking ability of a polymer-infiltrated ceramic-network material.

The aim of this in vitro study is to evaluate the masking ability of polymer-infiltrated ceramic-network materials (PICN) with different translucencies and thicknesses on multiple types of substrates. Ceramic samples were prepared of VITA ENAMIC blocks in two different translucencies (2M2-T, 2M2-HT) in a thickness range of 0.5-2.5 mm (±0.05 mm). Layered specimens were obtained using composite substrates in nine shades and transparent try-in paste. Spectral reflectance of specimens was measured using a Konica Minolta CM-3720d spectrophotometer and D65 standard illumination. CIEDE2000 color difference (ΔE00 ) between two samples was evaluated using 50%:50% perceptibility and acceptability thresholds. Specular component of the reflection was examined with Specular Component Excluded (SCE) and Included (SCI) settings. Statistical evaluation was performed by linear regression analysis, Kruskal-Wallis test, and multiplicative effect analysis. An increase in thickness of 0.5 mm reduces ΔE00 of HT samples to 73.5%, of T samples to 60.5% (p < 0.0001). Five substrates with HT specimens, and three substrates with T specimens had significantly different results from average (p < 0.05). There is a significant difference between SCE and SCI data depending on the wavelength (p < 0.0001). Masking ability of PICN materials is influenced by the thickness and translucency of the ceramic, and by the substrate. Reflection of the examined PICN material is characterized by both diffuse and specular reflection. Although PICN materials have been available on the market for 10 years now, there is a lack of information regarding their masking ability. Acquiring in-depth data and thereby practical experience of the factors affecting the esthetics of PICN materials is essential for creating perfectly lifelike restorations.

Effect of Translucency on Color Stability of Resin-based Composites

Effect of Translucency on Color Stability of Resin-based Composites

Effect of translucency of CAD-CAM ceramic restorative materials and scanning aid conditions on the accuracy of intraoral scans

Background/purposeSubsurface scattering from translucent material would affect the digital scans. This study aimed to evaluate the effect of translucency of ceramic restorative materials and scanning aid conditions on the accuracy of intraoral scans. Materials and methodsIdentical anatomic contour crowns with ten ceramic restorative materials were fabricated: five zirconia, three lithium disilicate glass-ceramic, and two leucite reinforced glass-ceramic. The models with ceramic crowns were digitized with an intraoral scanner (IOS) and analyzed for accuracy (n = 10) with and without a scanning aid. Scan time efficiency was recorded. Square-shaped specimens with 1.0-mm thickness were fabricated with the same materials, and translucency parameter (TP) values were measured. One-way ANOVA, Welch ANOVA, and a post-hoc pairwise comparison or independent t-test were used for trueness and time analysis, and the F-test was used to examine the precision (α = 0.05). Pearson correlation test was conducted. ResultsSignificant differences were revealed for trueness with no scanning aid condition and for TP values (P < 0.05). In contrast, no statistically significant differences were observed for trueness with a scanning aid. A strong correlation (r = 0.854, P < 0.01) between TP value and trueness with no scanning aid was revealed. By applying a scanning aid, trueness was improved and scan time efficiency significantly increased (P < 0.05). ConclusionThe translucency of ceramic restorative materials negatively affects the accuracy of IOS scan without a scanning aid; however, the scan accuracy and time efficiency of IOS scanning for ceramic restorations can be improved by applying scanning aid, and prostheses with high quality without unnecessary labor can be produced.

Effect of Translucency and Curing Mode of Four CAD/CAM Materials on Polymerization Efficiency of Light and Dual Cure Resin Cements.

To determine the effect of translucency of four CAD/CAM materials and different curing modes on the degree of conversion of resin cements. Disks were fabricated from IPS e.max CAD, Vita Suprinity, Vita Enamic, and DD Cube X². Translucency was measured using a spectrophotometer. The degree of conversion of two resin cements Variolink Esthetic DC and LC were measured using a Fourier transform infrared spectrometer. For Esthetic DC, the degree of conversion was determined in self-cure and dual cure modes. ANOVA, Tukey HSD test, and /Linear Regression R2 were used to statistically analyze the data. There was a significant difference in the translucency of the four materials (P ⟨ 0.0001). The mean translucency of Vita Suprinity was significantly higher, followed by Vita Enamic, DD Cube X², and IPS E.max CAD. Degree of conversion of resin cements cured under DD Cube X² had the highest values (25.22%), whereas those cured under Vita Suprinity showed the lowest values (17.86%). The self-cure mode had the lowest degree of conversion values (16.22%) and dual cure mode showed the highest values (26.12%). A negative linear relationship was found between degree of conversion and translucency of the CAD/CAM materials.

The Effect of Translucency and Surface Treatment on the Flexural Strength of Aged Monolithic Zirconia.

Aims This in vitro study aimed to evaluate the effect of the degrees of translucency in different types of monolithic zirconia as well as the aging and surface treatment with airborne particle abrasion on the flexural strength of monolithic zirconia. Materials and Methods Sixty bar-shaped specimens were fabricated from three different types of presintered monolithic zirconia (n = 20 per group) including low translucent (LT) (DD Bio ZW iso, high strength zirconia, Dental Direkt, Germany), high translucent (HT) (DD Bio ZX2 98, high translucent zirconia, Dental Direkt, Germany), and multilayered system (ML) (DD cubeX2®ML, multilayer, cubic zirconia system, Dental Direkt, Germany). Each monolithic zirconia group was equally subdivided according to be either air-abraded with 110 µm aluminium oxide particles or left untreated (control). After thermocycling, the flexural strength was measured by using a universal testing machine. Two-way ANOVA followed by Tukey's post hoc and independent samples t-test were used for the statistical analyses (P < 0.05). Results Surface treatment and types of zirconia were found to have a significant interaction (P = 0.010). Having controlled the effect of surface treatment, the flexural strength of HT and LT zirconia was found to be significantly higher than the ML zirconia system (P ≤ 0.001). Airborne particle abrasion could significantly decrease the flexural strength of monolithic zirconia only in ML zirconia (P = 0.002). Conclusions Multilayered zirconia system had the lowest flexural strength among all groups. Moreover, the flexural strength of this system was attenuated by surface treatment with airborne particles abrasion.

Effect of lithium disilicate ceramic thickness, shade and translucency on transmitted irradiance and knoop microhardness of a light cured luting resin cement

This in vitro study evaluates the influence of pressed lithium disilicate thickness, shade and translucency on the transmitted irradiance and the Knoop microhardness (KHN) of a light-cured resin cement at two depths. One hundred and thirty-five ceramic discs of IPS e.max Press (Ivoclar Vivadent) were fabricated and divided into twenty-seven groups (n = 5) according to the association between translucency: HT (hight translucency), LT (low translucency), and MO (medium opacity); shade: BL2, A1 and A3.5; and thickness: 0.5 mm, 1.5 mm, and 2.0 mm. One side of each ceramic disc was finished, polished and glazed. The irradiance (mW/cm²) of a multiwave LED light curing unit (Valo, Ultradent) was evaluated with a potentiometer (Ophir 10ª-V2-SH, Ophir Optronics) without (control group) or with interposition of ceramic samples. The microhardness of Variolink Esthetic LC resin cement (Ivoclar Vivadent) was evaluated after 24 h at two depths (100 μm and 700 μm). Data were submitted to ANOVA followed by Tukey’s test (α = 0.05). Irradiance and KHN were significantly influenced by ceramic thickness (p < 0.0001), shade (p < 0.001), translucency (p < 0.0001) and depth (p < 0.0001). Conclusions: the interposition of increasing ceramic thicknesses significantly reduced the irradiance and microhardness of resin cement. Increased depth in the resin cement showed significantly reduced microhardness for all studied groups. Increased ceramic opacity reduced the KHN of the resin cement at both depths for all ceramic thicknesses and shades.

Effect of ceramic thickness, translucency and cement shade on color masking ability of pressable zirconia based lithium silicate laminate veneer

Objective: This in-vitro study aimed to evaluate the effects of ceramic thicknesses and translucencies as well as resin cement shades on the masking ability of zirconia based lithium silicate discs (ZLC). Materials and Methods: Eighty-four ceramic discs were manufactured from high translucent (HT) and translucent (T) ZLC ceramic. Discs were divided into three equal subgroups, according to their thickness (0.5, 1, 1.5 mm). Background composite resin discs (shade C4D) were used to simulate the color of dark abutments. Ceramic discs were cemented to composite ones with either translucent or opaque resin cements. Color parameters were measured using a spectrophotometer and recorded by CIELab system, color difference between ceramic discs and cemented ceramic discs to composite were calculated as E. All data were statistically analyzed, using unpaired-t test, ANOVA test and Tukey HSD test. Statistical significance was set at p < 0.05. Results: A statistically significant color difference (E) was found between (HT) and (T) discs (P<0.05). E values of both translucencies were affected by ceramic thickness (P=0.000). Resin cement shade had no significant effect on E values when the thicknesses of ceramic veneer were 1.0 mm or 1.5 mm (P values=0.495 and 0.265 respectively). While the cement shades had a highly significant effect on E values when ceramic, disc thickness was 0.5mm. (P value<0.0001). Conclusion: As the veneer thickness increased, color change decreased significantly. Ceramic translucency and cement shade significantly influence the final color of pressable ZLC veneers only if the thickness is less than 1 mm.

Masking Tetracycline Stained Teeth: Effect of Translucency and Thickness of Multiple CAD-CAM Masking Tetracycline Stained Teeth: Effect of Translucency and Thickness of Multiple CAD-CAM Veneer Materials and Shades of Resin Cements

Abstract This study aimed to assess the masking potential of different CAD-CAM veneer restorations to restore tetracycline-stained teeth. One-hundred-eight CAD-CAM ceramic discs, shade 1M1, with high (HT) and low (LT) translucencies and 1mm and 0.7mm thicknesses were prepared from three CAD-CAM materials (IPS-e.max-CAD (EMC), VITA Enamic (VE) and Vita Suprinity (VS)). Resin cements, shades A1, white opaque (WO) and translucent (T), were used for cementation against a dark base. Color differences (ΔE*) between the restorations (veneer/resin cement/dark base) and a standard 1M1 shade-guide-tab were calculated. Mann-Whitney-U and Wilcoxon-signed-rank tests; and one-way ANOVA, Kruskal-Wallis and Bonferroni-post-hoc tests were used to compare between two and three groups respectively (P ≤0.05). Groups EMC-LT-0.7-T, VE-LT-1-A1 and VE-LT-1-T rendered restorations with ΔE* below the perceptibility threshold (<1.74), while EMC-LT-0.7-A1 and all LT-0.7mm VE restorations were within the acceptability threshold (<3.48). VS had significantly higher (ΔE*) compared to of EMC and VE materials. Ceramic thicknesses had no significant effect on (ΔE*), while the effect of translucency level of the ceramics and the shade of resin cement was significant. It was concluded that low translucency ceramic veneers can better mask darkly stained teeth, irrespective of their thicknesses, with resin cements shades affecting the color of the final restorations.

The effect of thickness and translucency of polymer-infiltrated ceramic-network material on degree of conversion of resin cements.

PURPOSEThe aim of the present study was to determine the degree of conversion of light- and dual-cured resin cements used in the cementation of all-ceramic restorations under different thicknesses of translucent (T) and high-translucent (HT) polymer-infiltrated ceramic-network (PICN) material.MATERIALS AND METHODST and HT PICN blocks were prepared at 0.5, 1.0, 1.5, and 2.0 mm thicknesses (n=80). Resin cement samples were prepared with a diameter of 6 mm and a thickness of 100 µm. Light-cured resin cement was polymerized for 30 seconds, and dual-cure resin cement was polymerized for 20 seconds (n=180). Fourier transform infrared spectroscopy (FTIR) was used for degree of conversion measurements. The obtained data were analyzed with ANOVA and Tukey HSD, and independent t-test.RESULTSAs a result of FTIR analysis, the degree of conversion of the light-cured resin cement prepared under 1.5- and 2.0-mm-thick T and HT ceramics was found to be lower than that of the control group. Regarding the degree of conversion of the dual-cured resin cement group, there was no significant difference from the control group.CONCLUSIONWithin the limitation of present study, it can be concluded that using of dual cure resin cement can be suggested for cementation of PICN material, especially for thicknesses of 1.5 mm and above.