The effect of three additives on properties of mineral trioxide aggregate cements: a systematic review and meta-analysis of in vitro studies

Abstract

Background: Several efforts have been made to improve mechanical and biological properties of calcium silicate-based cements through changes in chemical composition of the materials. This study aimed to investigate the physical (including setting time and compressive strength) and chemical (including calcium ion release, pH level) properties as well as changes in cytotoxicity of mineral trioxide aggregate (MTA) after the addition of 3 substances including CaCl₂, Na₂HPO₄, and propylene glycol (PG).

Methods: The systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Electronic searches were performed on PubMed, Embase, and Scopus databases, spanning from 1993 to October 2023 in addition to manual searches. Relevant laboratory studies were included. The quality of the included studies was assessed using modified ARRIVE criteria. Meta-analyses were performed by RevMan statistical software.

Results: From the total of 267 studies, 24 articles were included in this review. The results of the meta-analysis indicated that addition of PG increased final setting time and Ca²⁺ ion release. Addition of Na₂HPO₄ did not change pH and cytotoxicity but reduced the final setting time. Incorporation of 5% CaCl₂ reduced the setting time but did not alter the cytotoxicity of the cement. However, addition of 10% CaCl₂ reduced cell viability, setting time, and compressive strength.

Conclusion: Inclusion of 2.5% wt. Na2HPO4 and 5% CaCl2 in MTA can be advisable for enhancing the physical, chemical, and cytotoxic characteristics of the admixture. Conversely, caution is advised against incorporating elevated concentrations of PG due to its retarding effect.

Trial registration: PROSPERO registration number: CRD42021253707.

Keywords: Calcium chloride; Cell survival; Compressive strength; Mineral trioxide aggregate; Propylene glycol.

Fig. 1

The PRISMA flow diagram

Fig. 2

Forest plot of the meta-analysis evaluating the effect of PG addition to MTA on ST. A significant increase in the initial and final ST of MTA with the addition of 20% PG is noted. PG = propylene glycol, ST = setting time

Fig. 3

Forest plot of the meta-analysis evaluating the effect of Na2HPO4 addition to MTA on ST. The addition of Na2HPO4 decreased the final setting time, as with a higher percentage added, a more significant reduction in ST was evident. ST = setting time

Fig. 4

Forest plot of the meta-analysis evaluating the effect of Na2HPO4 on cytotoxicity. Regardless of additive concentration, there is no significant difference between MTA with added Na2HPO4 and MTA with no additive in 1 to 7 days. CV = cell viability

Fig. 5

Forest plot of the meta-analysis evaluating the Effect of CaCl2 on CS. In general, regardless of time point and the percentage of the additive, CaCl2 addition resulted in a reduction of CS. However, the subgroup meta-analysis indicated that the addition of 10% CaCl2 to MTA resulted in decreased CS on days 1 and 7 compared to MTA mixed with DW. However, this reduction was not significant on day 3. CS = compressive strength, DW = distilled water

Fig. 6

Forest plot of the meta-analysis evaluating the effect of CaCl2 on ST. The addition of both 5% and 10% CaCl2 to white MTA resulted in a reduction in the initial and the final ST. ST = setting time

Fig. 7

Forest plot of the meta-analysis evaluating the effect of CaCl2 on pH. The addition of 10% CaCl2 has no significant effect on the pH value after 24 h of evaluation

Fig. 8

Forest plot of the meta-analysis evaluating the effect of CaCl2 on cytotoxicity. The result of the subgroup meta-analysis indicated that the addition of 5% CaCl2 did not increase cell cytotoxicity of MTA on days 1, 3, and 7. However, the addition of 10% CaCl2 resulted in a significant reduction of cell viability on days 1 to 7 compared to MTA mixed with DW. CV = cell viability