“…Several studies (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19) have reported that maxillary premolars have a highly variable internal canal configuration, which can vary according to race and geographic origin (8,9,12). The reported prevalence of maxillary first premolars with 1 root ranges from 22% to 66%, with 2 roots from 33% to 84%, and with 3 roots from 0% to 6% (7,8,11,12,16,17,20).…”