Abstract: Abstract: Objective To explore the prevalence and distribution pattern of the root variations of permanent maxillary first and second molars in a Chinese Han population in Suzhou Prefecture. Methods Cone-beam computed tomography images of dentitions were collected retrospectively from 257 Han Chinese patients in Suzhou Stomatological Hospital. The incidences of the root variations were observed and determined. The trait frequency differences between genders and sides were tested with Chi-square tests. Correlations in the occurrence of the root variations between antimeric teeth were analyzed with the Spearman rank correlation test. Results The occurrence rate of fused roots in maxillary first molars was 3.1% (15/484 teeth). The frequency of maxillary second molars with 3 separated roots was 69.7% (285/409 teeth), and the bilateral concurrence rate was 66.1% (37/56). The differences between genders and sides were not statistically significant (P > 0.05). The most common variation form was the fusion of the mesiobuccal and distobuccal roots (11.7%), followed by the single rooted form (10.5%) and the fusion of the mesiobuccal and palatal roots (4.9).The correlation coefficient for the antimeric second molars was 0.607 (P < 0.01). Conclusion The root variation rarely occur in maxillary first molars whereas in maxillary second molars, the prevalence of fused roots is high in the Chinese Han population in Suzhou prefecture. It is of great clinical significance to understand and grasp their distribution patterns.

Key words: Permanent maxillary molar, cone-beam computed tomography, root variation