表 2.

超声器械和金刚砂车针预备后的肩台表面粗糙度

Surface roughness of shoulder after preparation of ultrasonic and rotary instruments

Items		Ultrasonic instruments	Rotary instruments	t value	P value
Ra/μm	Abutment	5.92±2.28	18.13±3.77	4.80	＜0.001
	Impression	6.59±2.33	21.79±4.89	5.10	＜0.001
Rz/μm	Abutment	29.01±5.91	80.99±12.02	7.10	＜0.001
	Impression	34.69±7.29	91.69±14.82	8.09	＜0.001