关键词: 上颌第一恒磨牙, 根管形态, 根管宽度, 根管锥度

Abstract: PURPOSE: To measure the root canal morphology of the maxillary first molars, to provide reference for clinical work. METHODS: Fifty maxillary first molars were collected and the mesiobuccal root canal taper was observed through production of transparent tooth. The mesiobuccal roots were dissected transversely from their apical foramen vertical to the long axis of the root and 0.4-mm-thick serial sections were made. Each section was observed with a stereomicroscope at 30× magnification to calculate the taper value of apical 1/3, middle third 1/3 and canal orifice 1/3. RESULTS: The width of MB1 root canal: maximum and minimum diameter of root apex was (0.38±0.12) mm and (0.34±0.16) mm, maximum and minimum diameter of root middle was (0.55±0.26) mm and (0.57±0.12) mm, maximum and minimum diameter of root collar was (1.13±0.34) mm and (0.59±0.18) mm. The width of MB2 root canal taper: maximum and minimum diameter of root apex was (0.25±0.13) mm and (0.28±0.10) mm, maximum and minimum diameter of root middle was (0.36±0.09) mm and (0.17±0.06) mm, maximum and minimum diameter of root collar was (0.79±0.23) mm and (0.23±0.17) mm. The taper of MB1 root canal: maximum and minimum diameter of root apical 1/3 was 0.03 and 0.01, maximum and minimum diameter of root middle 1/3 was 0.06 and 0.03, maximum and minimum diameter of root collar 1/3 was 0.10 and 0.09. The taper of MB2 root canal: maximum and minimum diameter of root apical 1/3 was 0.02 and - 0.01, maximum and minimum diameter of root middle 1/3 was 0.06 and 0.00, maximum and minimum diameter of root collar 1/3 was -0.02 and -0.02. CONCLUSIONS: MB1 has a larger width and taper, and root apical 1/3, middle 1/3, collar 1/3 have variable taper; While the width and taper of MB2 are small, and there will be upside down taper.

Key words: Maxillary first molars, Root canal morphology, Root canal width, Root canal taper