“…Moreover, 11 of the radiography-based investigations placed K-files (sizes 08, 10, 15) or silver points with the purpose of facilitating root canal curvature visualisation (Southard et al 1987, Backman et al 1992, Luiten et al 1995, Thompson et al 1995, Hankins & ElDeeb 1996, Harlan et al 1996, Lopes et al 1998, Dobo-Nagy et al 2000, Sch€ afer et al 2002, Iqbal et al 2003, G€ unday et al 2005. Five studies used micro-computed tomography (lCT) (Peters et al 2000, Bergmans et al 2001, Lee et al 2006, Eaton et al 2015, Dannemann et al 2017, two used cone-beam computed tomography (CBCT) (Estrela et al 2008, Choi et al 2015, and another two employed dental panoramic tomography (DPT) (Fuentes et al 2015(Fuentes et al , 2018. Three publications suggested an abstract, mathematically based method and presented diagrammatic representations for curvature and the measurement of other factors in the absence of any experimental component.…”