การทดสอบคุณสมบัติความต้านทานแรงดึงและแรงบิดของเดือยฟันสำเร็จรูป

Abstract

This in vitro study was to investigate the retention of prefabricated stainless steel posts by using
tensile and torsional forces and to consider correlation of these forces. The endodontic treatment and post
space preparation was done in forty mandibular premolars. The prefabricated post, ParaPost® model PP and
XP (Coltene/whaledent, Cuyahoga Falls, USA), 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
(model LR plus, Lloyd), while the torsional testing was conducted on a motorized cap torque tester (model
DTX, Nextech). The data were analyzed statistically by Independent T test. The result showed that XP group
presented significantly higher retentive value in both of tensile and torsional forces than PP group (p<0.05).
Both tensile and torsional forces progressed in the same direction. Torsional force values were less than tensile
forces approximately 20 times.