الفهرس 
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Abstract
7.1 Summary
Zinc oxide eugenol based sealers are the oldest type of sealers used in root canal treatment, Irrespective of the introduction of recent materials, ZOE has retained it’s position in endodontics, Despite of it’s known advantages (antibacterial and biocompatibility property), it lacks bioactivity and reminerlizing effects to interacts with the surrounding tissues thus improving it’s sealing efficiency. Other disadvantages include the long setting time and high solubility. On the other hand, cement bypass dust comes in huge amounts as a byproduct from the white Portland cement industries in Egypt.
This in vitro study was thus conducted to add CBPD to ZOE endodontic sealer in a trial to bioactivate it and then to asses some of it’s physicochemical properties.
One commercially available antibacterial ZOE based root canal sealer was chosen due to it’s availability and wide spread use in Egypt. Cement bypass dust as bioactive filler was received from Suez Cement Company.
The bypass dust powder was characterized using X-ray fluorescent analysis (XRF) and X-ray diffraction analysis (XRD) to determine the exact chemical composition of the powder.
However Transmission electron microscopic examination was done to determine the morphology of CBPD powder, microstructure and particle size.
The XRD and XRF showed that the CBPD powder was mainly calcium silicate hydroxide on the other hand TEM results revealed square shaped particles, while crystallinaty was revealed by uniform particle dimension.
As regard the setting time, a significant difference between the three tested groups was noticed with the controlled groups gave a longer setting time followed by group A while group B showed the least mean setting time value. Results also indicated that group B gave the highest means of solubility percentage followed by group A, however the control group showed the least solubility percentage value.
Moreover, results indicated a statistically significant level of Ca+2 release in-group B followed by group A, while no Ca+2 release was found regarding the control group.
Finally results of pH revealed that group B resulted in the highest mean pH value, followed by group A, while control group obtained the least mean pH value.
7.2 Conclusions
Within the limitations of this in vitro study, the following could be concluded;
1- Addition of CBPD powder affects the physcio-chemical properties of the tested ZOE sealer.
2- Calcium ion was released from the tested ZOE sealer following the addition of CBPD.
3- Increasing the CBPD weight percent requires the decrease in the P/L to obtain the flow specified by the ANSI/ADA specification.
4- Increasing the CBPD percent decreases the setting time and increases solubility of the tested ZOE sealer.
5- Addition of CBPD powder increases the pH of the tested ZOE sealer.
6- Finally it’s quite feasible to produce bioactive zinc oxide eugenol root canal sealers.
Recommendations:
The bioactivated zinc oxide and Eugenol based sealer should be tried In-vivo to test the biological properties and the bioactivity in contact to body fluids.