Effect of different water-to-powder ratios on the dimensional stability and compressive strength of mineral aggregate-based cements

Examining the Physicochemical Composition of Three Bioceramic Putties for Endodontic Use

OBJECTIVE

This study aimed to address the lack of comparative analyses of newly developed bioceramic materials by examining the chemical composition, thermodynamic profile, and microscopic surface features of three bioceramic putties: EndoSequence BC Root Repair Material Fast Set Putty (ESRRM-FS), BIO-C Repair (BCR), and Cera Putty (CP).

METHODS

Samples of each of the three bioceramic putty obtained directly from manufacturers were prepared for analysis of physicochemical composition and microscopic features by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) imagery, and energy-disper-sive X-ray spectroscopy (EDS). The data obtained was qualitatively and statistically analysed. Statistical signif-icance was determined at p≤0.05.

RESULTS

DSC analysis indicated a standard polymeric vehicle for BCR and CP, coinciding with the polyethene glycol (PEG) thermal profile; the polymeric vehicle in ESRRM-FS remains to be identified. The material with the highest heat capacity was CP (p<0.05), followed by ESRRM-FS and BCR. TGA revealed an inflexion point at 394.12 ºC for ESRRM-FS, which may correspond to the mass loss of dihydroxylation of calcium hydroxide. A more homogenous structure was observed in scanning electron microscopy (SEM) images for ESRRM-FS. EDS analysis indicated BCR had minimal amounts of aluminium (2.06+-0.44%) and a lower percentage of cal-cium than ESRRM-FS (9.11+-1.38% vs. 11.3+-0.87%). CP was composed of aluminium (49.35+-7.01%), carbon (30.65+-5.62%), and oxygen (16.75+-2.44%); no silicon was identified. ESRRM-FS had no aluminium present and the highest calcium percentage (11.3+-0.87%) (p<0.05).

CONCLUSION

BCR is a Portland cement-derived material with a lower percentage of calcium than ESRRM-FS and minimal amounts of aluminium. CP is a monocalcium aluminate cement, mainly composed of aluminium, carbon, and oxygen. ESRRM-FS is a biphasic material with the highest calcium percentage among all materials studied and no aluminium.

Portland Cement: An Overview as a Root Repair Material

Portland cement (PC) is used in challenging endodontic situations in which preserving the health and functionality of pulp tissue is of considerable importance. PC forms the main component of mineral trioxide aggregate (MTA) and demonstrates similar desirable properties as an orthograde or retrograde filling material. PC is able to protect pulp against bacterial infiltration, induce reparative dentinogenesis, and form dentin bridge during the pulp healing process. The biocompatibility, bioactivity, and physical properties of PC have been investigated in vitro and in animal models, as well as in some limited clinical trials. This paper reviews Portland cement's structure and its characteristics and reaction in various environments and eventually accentuates the present concerns with this material. This bioactive endodontic cement has shown promising success rates compared to MTA; however, considerable modifications are required in order to improve its characteristics and expand its application scope as a root repair material. Hence, the extensive chemical modifications incorporated into PC composition to facilitate preparation and handling procedures are discussed. It is still important to further address the applicability, reliability, and cost-effectiveness of PC before transferring into day-to-day clinical practice.

Physicochemical and Antibacterial Properties of Novel, Premixed Calcium Silicate-Based Sealer Compared to Powder-Liquid Bioceramic Sealer

The aim of this study was to compare the physicochemical properties, filling ability, and antibacterial activity of a premixed calcium silicate-based sealer to those of a powder–liquid bioceramic sealer. Ceraseal (CS) and BioRoot (BR) materials were analyzed using scanning electron microscopy and energy-dispersive X-ray spectroscopy at 7 and 14 d of immersion in distilled water. The filling ability of the two sealers as well as the water contact angle, solubility, flow, roughness, crystalline microstructure, pH, and compressive strength were also evaluated. The antibacterial activity was assessed through an agar diffusion as well as through direct tests. All the results were statistically analyzed using one-way or two-way analysis of variance tests. Statistically significant lower void percentages were observed for CS at 2 and 8 mm from the working length (WL) compared to those for the BR group, whilst no significant difference was observed at 5 mm from the WL. BR sealer showed higher alkaline pH, rougher surface, lower water contact angle values, lower flowability, and higher solubility compared to CS. BR showed globular and needle-like crystalline microstructure, whilst CS had globular and flower-like crystalline microstructure up to 72 h. No statistical difference was found for the compressive strength between the two sealers. BR and CS showed no antibacterial effect against Enterococcus faecalis after 3 h, whilst both sealers showed antibacterial capacity after 24 and 72 h. BR demonstrated higher antibacterial activity after 24 h. In conclusion, the use of bioceramic sealers may play an important role in controlling bacterial growth. Moreover, CS may have superior filling ability and lower solubility than the BioRoot sealer due to its specific chemical composition and mixing method.