Statement Of Problem: The esthetics of anterior lithium disilicate restorations can be enhanced if the buccal aspect is layered with a feldspathic ceramic. However, whether fractures and chipping of this layer are a prevalent complication is unclear.
Purpose: The purpose of this retrospective study was to evaluate the incidence of incisal fracture of a specially designed lithium disilicate reinforcement of the incisal edge for indirect anterior bilayered restorations on both teeth and implants.
Material And Methods: A total of 924 anterior bilayered pressed lithium disilicate restorations in 324 patients and made in one dental laboratory were delivered by 4 restorative dentists. The restorations had the palatal side of the incisal edge in monolithic lithium disilicate and the facial side in feldspathic porcelain. The restorations were evaluated for survival and the occurrence of fracture or chipping. Survival analyses were performed by using the Kaplan-Meier and log rank (Mantel-Cox) tests (α=.05).
Results: Of the 924 restorations, 798 (236 complete crowns, 562 partial restorations) were placed on teeth and 126 on implants. The mean observation time was 38 months (3 to 72 months). The survival rate was 96.5%, with 14 failures occurring. The failures were fracture after dental trauma (n=5), ceramic fracture (n=1), debonding (n=6), poor shade match (n=1), and tooth loss (n=2). Restorations in patients with parafunctional habits and endodontically treated teeth showed a significant decrease in survival rate (P=.018). No significant differences were found between the survival of restorations on teeth and implants and between complete crowns and partial restorations (P=.021). No chipping was observed on any restorations in the study.
Conclusions: Modified anterior bilayered ceramic restorations showed good survival rates, and no chipping was observed up to 6 years of follow-up. Parafunctional habits and endodontic treatment had a negative effect on the survival rate of restorations. The support of tooth or implant and the restoration type had no effect on the survival.
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http://dx.doi.org/10.1016/j.prosdent.2021.07.008 | DOI Listing |
Oral Health Prev Dent
January 2025
Purpose: This in-vitro study was conducted to assess the fracture resistance of resin-bonded ceramic endocrowns with different designs at varying intracoronal depths.
Materials And Methods: Forty-eight (n = 48) extracted mandibular first molar teeth were randomly divided into four groups (n = 12). In the control group, the specimens remained untreated.
J Prosthodont
January 2025
Division of Prosthodontics, Department of Restorative Sciences, University of Minnesota, Minneapolis, Minnesota, USA.
Purpose: This pilot study aimed to compare the flexural strength of Amber Mill CAD to IPS e.max CAD and to determine the impact of different crystallization protocols on the flexural strength of Amber Mill CAD ceramics.
Materials And Methods: Amber Mill CAD ceramic blocks of a known Vita Classic shade were selected for testing against control IPS e.
J Prosthet Dent
January 2025
Associate Professor and Director of Student Research, Division of Restorative and Prosthetic Dentistry, College of Dentistry, The Ohio State University, Columbus, OH. Electronic address:
Statement Of Problem: Currently there is no regulatory requirement or international standard for the wear resistance of dental materials and therefore no need to test prior to market launch.
Purpose: The purpose of this in vitro study was to evaluate and compare the total volumetric wear characteristics of milled polymer infiltrated ceramic network (MPICN) and printed polymer resin (PPR) as substrates opposing five antagonists, human enamel (EN), lithium disilicate (LD), zirconia (ZR), MPICN, and PPR, and to evaluate and compare the volumetric wear of these same materials as antagonists.
Material And Methods: Ten of each antagonist for a total of 50 EN, LD (IPS e.
J Mech Behav Biomed Mater
January 2025
Department of Civil and Environmental Engineering, University of Connecticut, Storrs, CT, 06269, USA. Electronic address:
This study aims to investigate the effects of material compatibility, variable cooling rates, and crown geometry on thermal stress development in porcelain-veneered lithium disilicate (PVLD) and porcelain-veneered zirconia (PVZ) dental crown systems, and subsequently anticipate parameters for their optimum performance. An anatomically correct 3D crown model was developed from STL files generated using 3D scans of the experimental crown sample. Next, the viscoelastic finite element model (VFEM) based on the 3D crown model was developed and validated for anatomically correct bilayer PVLD and PVZ crown systems.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Department of Cariology and Operative Dentistry, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, 1-5-45 Yushima, Bunkyo-Ku, Tokyo, 113-8549, Japan.
Background: Resin cements often require substrate-specific pretreatment. Recently, universal adhesive systems have been introduced, simplifying procedures by eliminating the need for multiple adhesives and offering options that do not require light curing. This study investigated the bonding performance of universal adhesive systems combined with dual-polymerising resin cements on enamel, dentin, zirconia, lithium disilicate ceramics (LDS), and resin blocks.
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