m. shariaty

Lead is a heavy metal that enters the body as an environmental contaminant through the gastrointestinal tract or respiratory tract. Therefore, the aim of the present study was to determine the effect of aqueous alcoholic extract of Parsley leaf (Petroselinum crispum) on pituitary-thyroid hormones in adult male rats following lead acetate poisoning.

The present experimental study was conducted in 2020 at the Islamic Azad University, Kazeron Branch. Forty-eight adult male Wistar rats were included in the study, which were divided into 6 groups of 8, including control and control groups (solvent treatment). Four experimental groups were treated with 200 mg / kg lead acetate, 200 mg / kg parsley leaf extract and simultaneously treated with lead acetate and 100 and 200 mg / kg parsley leaves. All prescriptions were performed by gavage for 21 days. Finally, after anesthesia of mice and blood sampling from animal hearts, serum levels of T4, T3 and TSH hormones were measured by ELISA method. The collected data were analyzed using analysis of variance and Tukey test.

The results indicated that serum levels of lead acetate T4 and T3 increased in animals receiving lead acetate and TSH showed a significant decrease at the level of p <0.05, while in animals treated with lead acetate and parsley leaf extract decreased T4 and T3 hormones. T3 and TSH increase are significant.

The data of the present study indicated that the hydroalcoholic extract of parsley leaves was able to moderate the increase in thyroid hormones caused by lead poisoning.

Screw loosening is a common problem with both screw-retained and cemented implant restorations. It is assumed that the abutment diameter affects detorque value and screw loosening. We aimed to determine the effect of two different abutment diameters on detorque value using cyclic loading and thermocycling.

This in-vitro experimental study was conducted on sixteen Morse-taper implants (4×10 mm) with two different diameters (3.9 and 5.2 mm) installed with a 25-Ncm torque (n=8). Eight screws from each group (3.9- and 5.2-mm abutments) were maintained for a month in a stable state while the rest of the screws underwent cyclic loading for 10,000 cycles with the frequency of 1 Hz and force of 75 N/cm. Then, thermocycling was done at 5-55°C. Detorque value was determined using the torque meter used for screw tightening. Removal torque values were recorded. Maximum deformation force and fracture resistance were documented. Data were analyzed according to Student's t-test using SPSS 21.0 software.

Detorque values were 18.25±1.91 and 21.13±1.46 Ncm with 3.9- and 5.2-mm abutments, respectively. Detorque loss value was 15.50±5.83% with 5.2-mm abutment and 27±7.63% with 3.9-mm abutment. The mean difference between the two abutment diameters was 2.87±0.85 Ncm. Significant differences were observed on torque loss with 3.9-mm- compared to 5.2-mm-diameter abutments (P=0.004).

The results suggested that torque loss was lower with 5.2-mm abutment diameter.