Table 6.

Summary of various developmental anomalies that have been reported in mandibular premolars.

Mandibular premolar	Developmental anomalies	Root/root canal anatomy	Diagnostic mode	Reference
1st premolar	Dens invaginatus	2 roots	R/G	Hartup [81], 1997
	Dens invaginatus	N/A	R/G	Bramante et al. [82], 1993
	Dens invaginatus	N/A	R/G	Tavano et al. [83], 1994
	Gemination	3 canals	R/G	Aryanpour et al. [84], 2002
	Dens invaginatus	1 root	R/G	Er et al. [85], 2007
	Dens invaginatus (bilateral)	N/A	R/G	Canger et al. [86], 2009
2nd premolar	Dens evaginatus	N/A	R/G	Koh et al. [87], 2001
	Fusion with mandibular first molar	5 canals	R/G	Tsesis et al. [88], 2003
	Fusion with supernumerary tooth	N/A	Clinical	Sathish Muthukumar et al. [89], 2012
	Taurodontism	3 canal	CBCT	Mokhtari et al. [77], 2013
	Taurodontism	5 canals	R/G	Demiryürek et al. [90], 2013

CBCT: cone beam computed tomography, R/G: radiograph, and N/A: not available.