Thesis (Ph.D)-Cairo University, 2023.

Bibliography: pages 61-66.

Aim: Mechanical properties of Polymer infiltrated ceramic network (PICN) range between that of resin-based composites and ceramics. Ongoing research on experimental PICNs shows impressive and promising results in terms of mechanical properties. The aim of this study was to evaluate the mechanical properties of a newly fabricated resin infiltrated lithium disilicate ceramic CAD/CAM block, in terms of; fracture load, flexural strength, fracture toughness, hardness and brittleness. Commercially available resin infiltrated feldspathic ceramic network was used as control.
Methodology: IPS e.max CAD/CAM blocks were grinded into powder and used to produce porous ceramic network (25% porosity). Methylmethacrylate resin was infiltrated and polymerized to form a dense PICN. Porosity percentage and microstructure were investigated. Crowns were milled from newly fabricated PICN blocks and Vita Enamic then fracture load test was performed. Rectangular specimens were prepared from both materials, afterwards, flexural strength, fracture toughness, brittleness and Vickers’ hardness tests were investigated. Data were analyzed by independent sample-t test and paired sample-t test (α = 0.05, n = 12).
Results: Newly formulated PICN had significantly higher fracture resistance (1640 N), fracture toughness (2.6 MPa m1/2) and lower brittleness index (0.89 μm1/2) compared to Vita Enamic (p < 0.001). In addition, no significant difference was found between the two materials in terms of hardness (p= 0.68) and flexural strength (p = 0.87).
Conclusion: Newly fabricated PICN material showed enhanced mechanical properties that can justify its selection and clinical application for successful restorative treatments

Mechanical properties of Polymer infilterated ceramic network (PICN) range between that of resin-based composites and porcelains. Ongoing studies on experimental PICNs shows promising results indicating that the mechanical properties of PICN can be enhanced by optimizing its chemical composition. The aim of this study is to evaluate the mechanical properties of a newly fabricated resin infiltrated ceramic CAD/CAM block where ceramic network is composed of glass-ceramic (lithium disilicate), in terms of ; flexural strength, fracture toughness, hardness, brittlness index and fracture load. Then compare it with commercially available resin infiltrated feldspathic ceramic network. Lithium disilicate CAD/CAM blocks were grinded into powder and used to produce a sintered porous ceramic network (25% porosity). Then, resin was infiltrated and polymerized to form a dense newly fabricated PICN. Rectangular specimens were prepared from both materials (n=12), Afterwards, flexural strength, fracture toughness, brittlnes index and Vickers’ hardness tests were investigated. Crowns were milled from newly fabricated PICN blocks and Vita Enamic (n=12) then fracture load test was performed. Results of this study showed that newly formulated PICN has significantly higher fracture load, fracture toughness and lower brittlness index compared to Vita Enamic. In addition, no significant difference was found between the two materials in terms of hardness and flexural strength . Those properties provides resistance against mechanical failure during occlusal loading while improving the millability of the material. This study results of newly fabricated PICN material can justify its selection and clinical application for successful and safe restorative treatments, however, further clinical studies are required in order to infer about the long-term behavior of this PICN in comparison with the already pre-established success and longevity of restorations with the classic ceramic-based restorative materials.

Issues also as CD.

Text in English and abstract in Arabic & English.