1,721,122 research outputs found
Color correspondence of different batches of TriLuxe CAD/CAM ceramic blocks
No full textTriLuxe ceramic blocks for chairside CAD/CAM procedures are color layered to allow natural esthetics, and only require subsequent glazing. The purpose of this study was to compare color repeatability of different batches of TriLuxe blocks. The three commercially available shades (1M2C, 2M2C, 3M2C) of TriLuxe blocks for the Cerec CAD/CAM system were examined. For each of the three colors, three different batches were tested, 5 blocks each. The measurements were made using a spectrophotometer equipped with an integrating sphere using the CIELab* colorimetric system. One-way ANOVA showed that the factor "Production Batch" was not statistically significant. Regarding deltaE, none of the 315 color comparisons (neither within the same shade, nor between specimens of the same batch, nor between specimens from different batches) exceeded the proposed deltaE = 3.3 threshold for clinical acceptability. All the different batches of the different shades of VITA TriLuxe blocks for the Cerec system showed the high degree of color correspondence necessary in industrially prefabricated CAD/CAM blocks
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Cement opacity and color as influencing factors on the final shade of metal-free ceramic restorations
No full textObjective: To investigate the influence of opacity and color of luting cements on the final shade of metal-free restorations. Materials and Methods: Five resin cement colors in combination with four different thicknesses of CAD/CAM ceramic materials were tested, and a composite substrate was used as dentin color reference (n = 3). Specimen color was measured with a spectrophotometer equipped with an integrating sphere before and after cementation (CIELAB). Cement and ceramic color and opacity (TP) were assessed by measuring the tested ceramic thickness as a 1-mm thick disk for each of the cement shades. The differences in color were evaluated (ΔE00). Data were statistically analyzed by a Two-Way ANOVA followed by the Tukey Test for post-hoc comparison (P <.05) and multiple comparison Pearson's test (P <.05); the acceptability and perceptibility threshold were evaluated. Results: Statistically significant influence was found for factors ceramic thickness and cement shade (P <.001). Perceptible and unacceptable color changes were induced on the final restoration by resin cements (ranging from ΔE00 = 0.69 ± 0.54 to ΔE00 = 5.53 ± 0.46), the correlation between factors became strong (r2 > 0.6) in case of mismatch between color and translucency of cement and ceramic. Only the clear shade in combination with the thickest ceramic, resulted in an imperceptible color change (ΔE00 = 0.69 ± 0.54). Conclusions: The final shade of ceramic restorations can be influenced by resin cements; the magnitude of influence is related to the cement optical properties. Clinical Significance: In order to influence the final shade of a ceramic restoration, a cement more opaque than the restorative material should be used. Conversely, in the case of a fitting shade of the restoration, a cement more translucent than the restoration should be used to avoid undesired changes
Bond strength to unground enamel and sealing ability in pits and fissures of a new self-adhering flowable resin composite
No full textObjective: To evaluate the applicability as a sealant of a new self-adhering flowable resin composite (Vertise Flow, Kerr, VF) by assessing shear bond strength (SBS) to unground enamel and microleakage (mu LKG) in sealed pits and fissures. Study Design: Marketed sealants to be used in combination with phosphoric acid (Guardian Seal, Kerr, GS) or with a self-etch adhesive (Adper Prompt-L-Pop/Clinpro Sealant, 3M ESPE, CS) were compared to VF. For SBS testing on unground enamel 10 molars per group were used. For mu LKG assessment, pits and fissures sealing was performed in 12 molars per group. The sealed teeth were immersed in a 50% weight silver nitrate solution for 24 hours and the extent of interfacial leakage was measured Between-group differences in SBS were assessed using One-Way Analysis of Variance (ANOVA), followed by Tukey test (p0.05). Results: SBS of VF was statistically similar to that measured by CS and higher than that of GS. Interfacial leakage was similar in the three groups. Conclusions: The finding of satisfactory bond strength and sealing ability of VF when compared to the marketed sealants encourages the use of VF in pit and fissure sealing
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