الفهرس 
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Abstract
This study was conducted to evaluate three perforation repair materials: Mineral Trioxide Aggregate (MTA), NeoMTA Plus, and Nano White MTA. In terms of, inflammatory tissue reaction, tissue healing and bioactivity after repair of furcal perforation defect. The research consists of two parts: an animal study and a laboratory study.
In the animal study using dog models, six adult Beagle dogs of both sexes were selected based on specific criteria. The study was approved by the ethical committee of the university, ensuring adherence to animal welfare guidelines.
The dogs were divided into two main groups based on the evaluation period: one month and three months after treatment. Each main group was further divided into three subgroups, and there were also two control groups.
Anesthesia was administered to the dogs before dental procedures. The teeth were then instrumented and perforations were created in the pulp chamber floor. Different materials were used for perforation repair in the experimental subgroups, while the positive control group had no repair and the negative control group had intact teeth.
After the observation period, the animals were sacrificed, and their maxillas and mandibles were evaluated histologically and immunohistochemically. The study aimed to assess inflammatory cell count and new hard tissue formation in the teeth.
The laboratory study assessed the physical and chemical properties of the three materials, this study used (NeoMTA plus, Nano WMTA, and MTA) to prepare a total of 60 discs. The discs were mixed according to the manufacturer’s instructions and packed into plastic molds. Mechanical vibration was applied to create a flat, regular surface. The diameter of each disc was 8.0 ± 0.1 mm, and the thickness was approximately 1.6 ± 0.1 mm. After setting, the samples were stored in an incubator with 99% relative humidity at 37°C for 24 hours.
The samples were then subjected to two types of tests:
I. Bioactivity Test: 10 discs of each material were soaked individually in 20 mL of simulated body fluid (HBSS) and kept at 37°C for 28 days. After the immersion period, the surface of each disc was analyzed using an Environmental Scanning Electron Microscope with energy-dispersive X-ray (EDX) analysis to assess the formation of calcium phosphate deposits (apatite) on the surfaces of the materials. The Ca/P ratio was then calculated based on the data obtained from the analysis
II. pH Changes Test: In this test, 10 samples of each material were placed in test glass tubes containing 10 mL of deionized water with a pH of 6.8. The tubes were stored at 37°C. The pH of the water was measured at specific intervals (3 hours, 24 hours, 72 hours, and 168 hours) using a pH meter that was calibrated with known pH solutions (pH 4, 7, 10). The measurements were taken at a constant temperature of 25 ± 2°C. The focus of this test was to evaluate the materials’ pH changes and their bioactivity.
In the animal study, results showed that histological evaluation of inflammatory cell count in the three experimental materials (MTA, NeoMTA Plus, and Nano WMTA) showed that all three materials had lower inflammatory cell counts compared to the positive control group.
There was no statistically significant difference in the inflammatory cell count among the three experimental materials, likely due to their high similarity in chemical composition.
Regarding the effect of time periods on inflammatory cell count, all materials showed a higher inflammatory reaction at the one-month period, which decreased at three months.
In terms of immunohistochemical analysis for new hard tissue formation, the positive control group showed no scores for new hard tissue formation at both time periods. There was no statistically significant difference in new hard tissue formation between the three experimental materials (NeoMTA plus, NanoWMTA, and MTA) within both one-month and three-month periods. After three months, there were significantly higher scores of hard tissue formation attributed to the materials.
In the laboratory study, results regarding the bioactivity, showed that There was no statistically significant difference between (Neo-MTA Plus), (Nano-W MTA) and (MTA). The Higher Ca/P ratio was found in (Nano-WMTA) while the Lower Ca/P ratio was found in (MTA).
Regarding pH changes. The three experimental materials induced the alkalinization of the deionized water after three hours of immersion. The pH decreased starting at three days continuing until the last test at seven days. Regarding the effect of time, there was no statistically significant difference between (Neo-MTA Plus), (Nano-W MTA) and (MTA). The highest mean value was found in (Nano-W MTA) while the least mean value was found in (MTA).
Based on the results of the current study, the following could be concluded:
• They are able to induce new hard tissue formation, reduce inflammation over time, and exhibit bioactivity. These make them valuable candidates for future clinical applications.
• Healing potentiality of the tested materials improved by time.
• Nano-WMTA revealed superior biocompatibility and enhanced bioactivity comparable to MTA when used as a perforation repair material.
RECOMMENDATIONS:
Based on the findings of this study, several recommendations can be made:
1- Perform comparative studies between the three tested materials and other commonly used root repair materials. This will help dental practitioners in selecting the most effective and suitable material for specific clinical situations.
2- Develop clear clinical guidelines and protocols for the proper use of these materials in furcal perforation repairs.
3- Conduct long-term studies to evaluate the longevity and durability of the repaired furcation sites treated with these materials.