Hydraulic Calcium Silicate Cements Research Articles

Calcium silicate bioactive cements: Biological perspectives and clinical applications

ObjectiveTo introduce and to examine the research progress and the investigation on hydraulic calcium silicate cements (HCSCs), well-known as MTA (mineral trioxide aggregate). MethodsThis review paper introduces the most important investigations of the last 20 years and analyze their impact on HCSCs use in clinical application. ResultsHCSCs were developed more than 20 years ago. Their composition is largely based on Portland cement components (di- and tri-calcium silicate, Al- and Fe-silicate). They have important properties such as the ability to set and to seal in moist and blood-contaminated environments, biocompatibility, adequate mechanical properties, etc. Their principal limitations are long setting time, low radiopacity and difficult handling.New HCSCs-based materials containing additional components (setting modulators, radiopacifying agents, drugs, etc.) have since been introduced and have received a considerable attention from laboratory researchers for their biological and translational characteristics and from clinicians for their innovative properties.HCSCs upregulate the differentiation of osteoblast, fibroblasts, cementoblasts, odontoblasts, pulp cells and many stem cells. They can induce the chemical formation of a calcium phosphate/apatite coating when immersed in biological fluids.These properties have led to a growing series of innovative clinical applications such as root-end filling, pulp capping and scaffolds for pulp regeneration, root canal sealer, etc.The capacity of HCSCs to promote calcium-phosphate deposit suggests their use for dentin remineralization and tissue regeneration. Several in vitro studies, animal tests and clinical studies confirmed their ability to nucleate apatite and remineralize and to induce the formation of (new) mineralized tissues. SignificanceHCSCs play a critical role in developing a new approach for pulp and bone regeneration, dentin remineralization, and bone/cementum tissue healing. Investigations of the next generation HCSCs for “Regenerative Dentistry” will guide their clinical evolution.

Clinical and Technical Considerations of Luting Agents for Fixed Prosthodontics

Clinical and Technical Considerations of Luting Agents for Fixed Prosthodontics

Quantitative Evaluation by Glucose Diffusion of Microleakage in Aged Calcium Silicate-Based Open-Sandwich Restorations

This study compared the in vitro marginal integrity of open-sandwich restorations based on aged calcium silicate cement versus resin-modified glass ionomer cement. Class II cavities were prepared on 30 extracted human third molars. These teeth were randomly assigned to two groups (n = 10) to compare a new hydraulic calcium silicate cement designed for restorative dentistry (Biodentine, Septodont, Saint Maur des Fossés, France) with a resin-modified glass ionomer cement (Ionolux, Voco, Cuxhaven, Germany) in open-sandwich restorations covered with a light-cured composite. Positive (n = 5) and negative (n = 5) controls were included. The teeth simultaneously underwent thermocycling and mechanocycling using a fatigue cycling machine (1,440 cycles, 5–55°C; 86,400 cycles, 50 N/cm2). The specimens were then stored in phosphate-buffered saline to simulate aging. After 1 year, the teeth were submitted to glucose diffusion, and the resulting data were analyzed with a nonparametric Mann-Whitney test. The Biodentine group and the Ionolux group presented glucose concentrations of 0.074 ± 0.035 g/L and 0.080 ± 0.032 g/L, respectively. No statistically significant differences were detected between the two groups. Therefore, the calcium silicate-based material performs as well as the resin-modified glass ionomer cement in open-sandwich restorations.

Pulp preservation in immature permanent teeth

New treatment strategies for direct pulp capping and pulpotomy have shown promising potentials for improved outcomes in immature teeth with extensive caries, traumatic pulp exposures, or anatomical anomalies. Preservation and protection of the dental pulp in developing teeth promote root maturation and extend tooth survivability by postponing or even preventing more complex endodontic and restorative care. Early intervention using hydraulic calcium silicate cements such as mineral trioxide aggregate (MTA) stimulates pulpal cell recruitment and differentiation, up‐regulates transformation factors (gene expression), and promotes dentinogenesis. Calcium hydroxide, resin‐modified glass ionomer cements, hydrophilic resins, and formocresol have been shown to be less effective as bioactive agents when used in vital pulp therapy. Improved treatment procedures for pulp preservation include the use of caries detector dye to preserve the remineralizable inner carious layer and the use of sodium hypochlorite as a hemostatic and diagnostic agent to differentiate reversible from irreversible pulpitis. Although stepwise excavation and the use of calcium hydroxide is still being advocated, pulp capping and pulpotomy procedures using calcium silicate‐based cements are becoming widely accepted as more effective procedures. MTA and new hydraulic calcium silicate cements provide biocompatible environments that predictably promote reparative dentin bridge formation when placed under properly bonded and sealed composite restorations. Hydraulic calcium silicate cements appear to provide a promising future for the preservation of pulpal integrity in immature teeth when used with modified and conservative treatment protocols.

Aspects of the in vitro bioactivity of hydraulic calcium (alumino)silicate cement

In response to a burgeoning interest in the prospective clinical applications of hydraulic calcium (alumino)silicate cements, the in vitro bioactivity and dissolution characteristics of a white Portland cement have been investigated. The formation of an apatite layer within 6 h of contact with simulated body fluid was attributed to the rapid dissolution of calcium hydroxide from the cement matrix and to the abundance of pre-existing Si--OH nucleation sites presented by the calcium silicate hydrate phase. A simple kinetic model has been used to describe the rate of apatite formation and an apparent pseudo-second-order rate constant for the removal of HPO4(2-) ions from solution has been calculated (k(2) = 5.8 x10(-4) g mg(-1) min(-1)). Aspects of the chemistry of hydraulic cements are also discussed with respect to their potential use in the remedial treatment of living tissue.