ผลของลักษณะพื้นผิวของเดือยฟันสำเร็จรูปชนิดเหล็กกล้าไร้สนิมต่อความต้านทานแรงดึง และแรงบิดหมุน / อลิสา วิชัยธนารักษ์ = Effect of surface configurations of prefabricated stainless steel posts on resistance to tensile and torsional forces / Alisa Vichaithanaruk
This study was to investigate the retention of prefabricated stainless steel posts, which had difference in surface configurations, by using tensile and torsional forces. The endodontic treatment and post space preparation with ParaPost set drill no.5 was done in one-hundred mandibular premolars. The prefabricated post, ParaPost® model PP and XP (Small helixes with vertical vent, Raised diamond shape pattern) and experimental posts model TPP1, TPP2, and SSP (Large helixes, Small helixes and smooth surface), were secured with zinc phosphate cement, then randomly divided for tensile and torque test (n=10). The tensile testing was performed on the universal testing machine (Lloyd) with cross head speed 5mm/min, while the torsional testing was conducted on a motorized cap torque tester (Nextech) in clockwise direction. The data were analyzed with one way analysis of variance and Bonferroni’s test (α= 0.05). The result showed that TPP1 and XP presented the greatest resistance to tensile forces (395.73 ± 46.38 and 391.09 ± 43.47 N) and torsional forces (23.67 ± 4.19 and 23.54 ± 3.88 N-cm) while SSP showed low resistance to both types of force (147.80 ± 27.85 N and 6.33 ± 1.48 N-cm). Both tensile and torsional forces progressed in the same direction. Torsional force values were less than tensile forces approximately 20 times. The conclusion could be the resistance to tensile and torsional forces of prefabricated post was affected by surface configuration (p < 0.05). The stainless steel posts with large and deep patterns provided better resistance to tensile and torsion forces.