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Abstract This in-vitro study was conducted to modify conventional glass ionomer cement(GIC) with Salvadora persica (Miswak) extract (SPE) at three different concentrations (SPE 8%, SPE 10%, SPE 15%). The modified groups of glass ionomer cement were evaluated and compared to the control group (SPE 0%) in terms of compressive strength, bond strength, fluoride release, film thickness, setting time and antibacterial activity. Compressive strength was tested following the ADA specification no.66 for glass ionomer cements. Cylindrical specimens were prepared and tested using a universal testing machine. The specimens were placed in vertical position and compressive load was applied along the long axis of the specimens until fracture. The maximum load applied when the specimen fracture was recorded and the compressive strength was calculated. The bond strength was evaluated by shear bond strength test to dentin. Premolar teeth extracted for orthodontic reasons were used after being flattened and embedded in gypsum. The mixed cement was placed in a mould that was placed centrally on the dentin surface of the tooth. All specimens were tested using the universal testing machine. Fluoride release test was performed by preparing cylindrical specimens which was then immersed and stored in plastic containers in deionized water. The amount of released fluoride was evaluated at different time intervals (1, 4, 7, 14 and 21 days) using an Ion selective electrode(ISE). Fluoride release was calculated as the amount of fluoride released per unit surface area of specimen (μg/cm2). 99 Film thickness was measured by recording the combined thickness of two optically flat glass plates stacked in contact and this measurement was designated as a Reading (A). A standardized amount of each cement mixture was placed between the two glass plates. Ten seconds before the end of the manufacturer’s stated working time, a force of (150 ± 2) N was applied vertically and centrally on the upper glass plate. Ten minutes later, the overall thickness of the plates and the cement was recorded as a Reading (B). The difference between readings A and B was considered as the thickness of the film. Setting time was measured using an indenter with a mass of 400 ± 5g, it is a needle having a flat end that is perpendicular to the long axis of the needle. The indenter will be placed on the cement’s surface and the surface will be inspected for any indentation. The setting time was measured from the start of mixing till the time when the indenter failed to make complete circular indentation on the surface The antibacterial activity of GICs was evaluated using agar diffusion test against Streptococcus Mutans and Lactobacillus Casei under aseptic conditions. Specimens were placed in petri dishes containing the nutrient medium with the bacterial inoculum and incubated for 24 hours. Positive results were scored when a zone of inhibition is formed around the specimens where the diameter of the zone was measured using a digital calliper. Results of the compressive strength test revealed that the modified groups were significantly higher compared to the control group. While for the bond strength test, the three modified groups showed statistically significant lower mean values compared to the control group. The mean cumulative fluoride release after 21 days for the each of the modified groups was significantly lower than the control group. However, there was a rapid initial release rate after 1 day for all the tested groups that gradually slowed down over the experimental period. Film thickness test results showed no statistically significant difference between all the tested groups. However, there was a significant shortening of the setting time of the modified groups compared to the control group. Moreover, such effect on setting time was found to be concentration dependent. The modified groups showed significantly higher zone of inhibition against Stepptoccous Mutans while no significant difference in inhibition zones was recorded against Lactobacillus Casei compared to the control group. Under the limitations of this study, the following could be concluded: 1. The addition of Salvadora persica (Miswak) extract (SPE) had a positive effect on compressive strength of glass ionomer cement. 2. SPE enhances the antibacterial activity of glass ionomer cement against Streptococcus Mutans, with no pronounced effect against Lactobacillus Casei. 3. The addition of SPE to glass ionomer cement shortened the setting time and did not alter the film thickness. 4. Modification of glass ionomer cement with SPE had a negative impact on the bond strength and fluoride release of glass ionomer cements. |