الفهرس 
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Abstract
Summary
The aim of this study was to evaluate the efficacy of a tricalcium silicate-based cement; Matreva MTA modified with three different concentrations (10%, 20%, 30% by weight) of Aloe vera (AV) based solutions as a pulp capping material, in comparison to Biodentine cement regarding their physical properties including setting time and flow, bioactivity including biointeractivity (alkalizing activity and calcium ion release), and in vitro bioactivity (apatite forming ability). Moreover, biological behavior in experimental animals including inflammatory cell response of the pulp tissue and dentin bridge formation were evaluated.
One hundred and thirty-five specimens were prepared and divided into five groups according to the tested material (n=27); group I (Biodentine), group II (Matreva MTA), group III (Matreva MTA with 10% AV), group IV (Matreva MTA with 20% AV) and group V (Matreva MTA with 30% AV). characterization for each group was carried out using ESEM, EDX, XRD, and FTIR. The flow and setting time were assessed following ISO standard 6876:2012 and ASTM standard C266-8 respectively. Both initial and final setting times were measured using Gilmore needles. In addition, bioactivity was evaluated at three-time intervals (1, 14, and 28 days) after immersion in Hank’s balanced salt solution (HBSS) in terms of pH measurement, calcium ion release, and in vitro apatite forming ability. A digital pH meter was used for pH measurements while ICP-MS was used for the detection of calcium ion release. Moreover, ESEM/EDX, XRD, and FTIR analyses were used to evaluate the in vitro bioactivity.
For in vivo assessment of biological response, the materials were then used as direct pulp capping materials in dogs. A total of 90 teeth were included in this study, where 30 teeth were treated per dog. After general anesthesia, class V buccal cavity was prepared and the pulp was exposed. The different capping materials were then applied on the exposure sites and the cavities were restored with glass ionomer filling. Teeth were demineralized, embedded in paraffin, and sectioned vertically through the capping site at an average thickness of 6 µm. All histopathological findings including inflammatory cell response and dentin bridge formation were recorded at three different time intervals 2, 4, and 8 weeks. Data were statistically analyzed using one-way ANOVA for setting time and flow and two-way mixed model ANOVA for pH, ion release, inflammatory cell count, and dentin bridge thickness followed by Tukey’s post hoc test for pairwise multiple comparisons(P≤0.05).
Increasing the concentration of AV solution from 0 to 30% resulted in a decrease in the mean flow value, the initial and final setting time. Higher mean values of pH and calcium ion release were observed for 20% and 30% AV-modified MTA cement at 14- and 28-day time intervals (p≤0.05). ESEM/EDX analysis confirmed the ability to nucleate calcium phosphates on the surfaces of the cements after immersion in HBSS where Biodentine and AV-modified Matreva MTA showed higher Ca/P ratios at different time intervals compared to unmodified Matreva MTA.
In the animal study, the results showed that inflammation was resolved by time with a significant difference within the same group. Unmodified Matreva MTA and Biodentine groups showed the highest inflammatory cell count compared to the AV-modified Matreva MTA groups at 2- and 4-week intervals while an insignificant difference in the inflammatory cell count was recorded at 8 weeks for all groups. The thickness of the dentin bridge was significantly higher in AV-modified Matreva and Biodentine groups in comparison to unmodified Matreva MTA throughout the follow up periods. In all groups, partial and complete dentin bridges were mainly observed at 4 weeks with improvement in continuity and thickness at 8 weeks. However, Biodentine and AV-modified Matreva groups demonstrated early signs of calcification at the 2 weeks’ time interval.