Statement Of Problem: A dark-colored prepared abutment tooth may negatively affect the esthetic outcome of a ceramic restoration if the tooth is restored using translucent enamel-like ceramic materials.
Purpose: The purpose of this study was to evaluate the cumulative effect that the tooth abutment color, cement color, and ceramic thickness have on the resulting optical color of a CAD/CAM glass-ceramic lithium disilicate-reinforced crown.
Material And Methods: A CAD/CAM glass-ceramic lithium disilicate-reinforced monolithic crown (IPS e.max CAD LT) was fabricated. Three possible crown restoration variables were tested in vitro. The procedure examined 4 prepared abutment tooth colors (light, medium light, medium dark, and dark), 2 cement (Variolink II) colors (translucent and opaque), and 4 ceramic thickness values (1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm). The color of each combination was measured using a spectrophotometer, and the average values of the color difference (ΔE) were calculated. The data were analyzed with a 3-way ANOVA (tooth abutment color, ceramic thickness, and luting agent) and Tukey's HSD test (α=.05), which evaluated within-group effects of the tooth abutment color to the ΔE at each ceramic thickness.
Results: The ΔE values of a CAD/CAM glass-ceramic lithium disilicate-reinforced crown were significantly influenced by the tooth abutment color (P<.001), cement color (P<.001), and ceramic thickness (P<.001). Significant interactions were present among these 3 variables (P<.001). A dark-colored abutment tooth demonstrated the greatest ΔE values relative to other variables tested. An increase in ceramic thickness resulted in a significant decrease in ΔE values (P<.01). The ΔE values were slightly decreased when the crowns were cemented using the opaque cement.
Conclusions: This study demonstrated that underlying tooth abutment color, cement color, and ceramic thickness all influence the resulting optical color of CAD/CAM glass-ceramic lithium disilicate-reinforced restorations.
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http://dx.doi.org/10.1016/S0022-3913(11)60004-8 | DOI Listing |
Clin Implant Dent Relat Res
February 2025
State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
Objectives: To compare the clinical effectiveness of a novel bioceramic (BC) with a control xenograft (BO) for guided bone regeneration (GBR) performed simultaneously with implant placement.
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Small
January 2025
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
PbZrO (PZO) thin films, as a classic antiferroelectric material, have attracted tremendous attention for their excellent dielectric, electromechanical, and thermal switching performances. However, several fundamental questions remain unresolved, particularly the existence of an intermediate phase during the transition from the antiferroelectric (AFE) to ferroelectric (FE) state. Here, a phase coexistence configuration of an orthorhombic AFE phase and a tetragonal-like (T-like) phase is reported in epitaxial antiferroelectric PZO thin films, with thickness ranging from 16 to 110 nm.
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January 2025
CSIR-Advanced Materials and Processes Research Institute (CSIR-AMPRI), Bhopal, Madhya Pradesh, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, India. Electronic address:
Conversion of caustic red mud (RM, Alumina industry waste) into building materials becoming one of the viable solution for its large scale utilization. The building materials developed using RM often results in efflorescence due to its high alkalinity, which is detrimental for the structural integrity of the buildings. The X-ray shielding tiles developed through ceramic route using the mixtures of RM, BaSO and kaolin clay also suffers from severe NaSO efflorescence when sintered above 1000 °C.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104.
Dorsal closure is a process that occurs during embryogenesis of . During dorsal closure, the amnioserosa (AS), a one-cell thick epithelial tissue that fills the dorsal opening, shrinks as the lateral epidermis sheets converge and eventually merge. During this process, both shape index and aspect ratio of amnioserosa cells increase markedly.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Chemical Engineering, Kansas State University, Manhattan, KS, USA.
Protonic ceramic electrochemical cells (PCECs) can operate at intermediate temperatures (450° to 600°C) for power generation and hydrogen production. However, the operating temperature is still too high to revolutionize ceramic electrochemical cell technology. Lowering the operating temperature to <450°C will enable a wider material choice and reduce system costs.
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