Biocompatibility of Glass Ionomer Cement

Glass polyalkenoate cements (GPCs) have been used in dentistry for over 40 years. These novel bioactive materials are the result of a reaction between a finely ground glass (base) and a polymer (acid), usually poly(acrylic acid) (PAA), in the presence of water. This article reviews the types of PAA used as reagents (including how they vary by molar mass, molecular weight, concentration, polydispersity and content) and the way that they control the properties of the conventional GPCs (CGPCs) formulated from them. The article also considers the effect of PAA on the clinical performance of CGPCs, including biocompatibility, rheological and mechanical properties, adhesion, ion release, acid erosion and clinical durability. The review has critically evaluated the literature and clarified the role that the polyacid component of CGPCs plays in setting and maturation. This review will lead to an improved understanding of the chemistry and properties of the PAA phase which will lead to further innovation in the glass-based cements field.

Nanohydrogel combines the advantages of hydrogel and nano particulate systems. Similar to the hydrogel and macrogel, nanohydrogel can protect the drug and control drug release by stimuli responsive conformation or biodegradable bond into the polymer networks. Nanohydrogel has drawn huge interest due to their potential applications, such as carrier in target-specific controlled drug delivery, absorbents, chemical/biological sensors, and bio-mimetic materials. Similar to the nanoparticles, stimuli responsive nanohydrogel can easily be delivered in the liquid form for parenteral drug delivery application. This review highlights the methods to prepare nanohydrogel based on natural and synthetic polymers for diverse applications in drug delivery. It also encompasses the drug loading and drug release mechanism of the nanohydrogel formulation and patents related to the composition and chemical methods for preparation of nanohydrogel formulation with current status in clinical trials.

Four types of bioactive nano-silica were prepared by different methods, and were used to
mprove commercial dental Glass Ionomer Cement (GIC) bioactivity. The prepared powder sam-
ples were characterized by X-ray diffraction (XRD) to identify the formed phase; particle size
and morphology were assessed by transm ission electron microscope (TEM). The bioactivity of
he prepared powder samples and its dental cement blends were applied in simulated body fluid
SBF). The change in surface morphology and composition after soaking in SBF after week at
37  C were determined by scanning electron microscopy with energy dispersive spectroscopy
SEM with EDS) and Fourier transform infrared analyses (FTIR). Our results confirmed that
he prepared silica powder exists in nano-scale. Precipitations of carbonate–apatite on the silica
urface were observed by FT-IR spectroscopy and scanning electron microscopy. Silica dissolution
and re-precipitation phenomena were also observed from SEM. The relationship between both
phenomena during the in vitro test is discussed mainly in terms of structural and microstructural