Polymer-infiltrated Ceramics Research Articles

Bioactive and inert dental glass-ceramics.

The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 619-639, 2017.

Ceramic-Reinforced Polymers: CAD/CAM Hybrid Restorative Materials

Newly developed ceramic-reinforced polymers CAD/CAM restorative materials (CRP) represent a viable esthetic material for dental restorations. They can be classified into polymer-infiltrated ceramic (PIC) and resin nano-ceramic (RNC). This review article analyzes the latest scientific findings on wear, fatigue resistance, bonding mechanisms, fracture resistance, and esthetic properties. The literature shows that fatigue resistance of ceramic-reinforced polymers appears to be adequate to survive the masticatory forces. PIC and RNC CAD/CAM blocks have similar fracture toughness, but lower than that of ceramic-based CAD/CAM blocks. The roughness of polished different ceramic-reinforced polymers is comparable; however, aging increases the surface roughness significantly. Different CRPs require a dedicated surface treatment; nonetheless, PIC and RNC are able to attain high bond strengths. The esthetic properties of CRPs are clinically acceptable. Ceramic-reinforced polymers appear to be an ideal material for minimally invasive restorations.

Effects of High-Temperature-Pressure Polymerized Resin-Infiltrated Ceramic Networks on Oral Stem Cells.

ObjectivesThe development of CAD—CAM techniques called for new materials suited to this technique and offering a safe and sustainable clinical implementation. The infiltration of resin in a ceramic network under high pressure and high temperature defines a new class of hybrid materials, namely polymer infiltrated ceramics network (PICN), for this purpose which requires to be evaluated biologically. We used oral stem cells (gingival and pulpal) as an in vitro experimental model.MethodsFour biomaterials were grinded, immersed in a culture medium and deposed on stem cells from dental pulp (DPSC) and gingiva (GSC): Enamic (VITA®), Experimental Hybrid Material (EHM), EHM with initiator (EHMi) and polymerized Z100™ composite material (3M®). After 7 days of incubation; viability, apoptosis, proliferation, cytoskeleton, inflammatory response and morphology were evaluated in vitro.ResultsProliferation was insignificantly delayed by all the tested materials. Significant cytotoxicity was observed in presence of resin based composites (MTT assay), however no detectable apoptosis and some dead cells were detected like in PICN materials. Cell morphology, major cytoskeleton and extracellular matrix components were not altered. An intimate contact appeared between the materials and cells.Clinical SignificanceThe three new tested biomaterials did not exhibit adverse effects on oral stem cells in our experimental conditions and may be an interesting alternative to ceramics or composite based CAD—CAM blocks.

Influence of pressure-assisted polymerization on the microstructure and strength of polymer-infiltrated ceramics

A method of manufacturing polymer-infiltrated ceramics (PICs) is to pre-infiltrate a porous ceramic with a liquid monomer and subsequently polymerize the organic component inside the ceramic structure. The volume reduction during polymerization leads to the formation of pores (defects), which has a detrimental effect on the mechanical properties of PICs. To avoid the generation of defects, a new polymerization method that uses pressure during polymerization was developed. To investigate the influences of pressure and heating rate on strength and microstructure, both parameters were varied. The influences of both parameters on the strength of PICs were studied using a biaxial test. The influence on the microstructure was investigated through microscopy. Fracture toughness and R-curve behavior of the manufactured PICs were determined with the SEVNB method. The process parameters have a strong influence on strength and microstructure of PICs. Defect-free PICs with improved strength could be manufactured using elevated pressure during polymerization. As expected, a distinct R-curve behavior and enhanced fracture toughness relative to composites manufactured using conventional methods was found. The developed manufacturing method leads to defectless PICs with increased mechanic behaviors.

Investigation of the Adhesion Promoter Distribution in Porous Ceramic Precursors

The purpose of this paper is to improve the mechanical properties of polymer infiltrated ceramics (PICs) by the enhancement of the adhesion between both components. To improve the interface adhesion, an adhesion promoter (silane) was used. The silane distribution in the precursors was studied using Raman and IR spectroscopy. Inhomogeneous silane distribution was found after applying a common surface modification method. In this paper, different silane modification methods were developed. The methods differ in the manner of the infiltration solution, the point of silane activation, and the infiltration pressure. The impacts achieved by the use of these methods were analyzed, and different adhesion mechanisms between silane molecules and the ceramic surface were established. As a result, a unique infiltration method which generates homogeneous silane distributions was developed. The interface adhesion depends among other parameters on the silane amount on the surface. The adjustment of the silane amount in the precursor was realized by the use of IR-spectroscopy.