Table 1.

Description of the different formation stages A–H according to Demirijan et al. [15]

Stage	Description
A	In both uniradicular and multiradicular teeth, a beginning of calcification is seen at the superior level of the crypt in the form of an inverted cone or cones. There is no fusion of these calcified points.
B	Fusion of the calcified points forms one or several cusps which unite to give a regularly outlined occlusal surface.
C	(a) Enamel formation is complete at the occlusal surface. Its extension and convergence towards the cervical region is seen. (b) The beginning of a dentinal deposit is seen (c) The outline of the pulp chamber has a curved shape at the occlusal border.
D	(a) The crown formation is completed down to the cementoenamel junction. (b) The superior border of the pulp chamber in the uniradicular teeth has a definite curved form, being concave towards the cervical region. The projection of the pulp horns if present, gives an outline shaped like an umbrella top. In molars, the pulp chamber has a trapezoidal form. (c) Beginning of root formation is seen in the form of a spicule.
E	Uniradicular teeth:   (a) The walls of the pulp chamber now form straight lines, whose continuity is broken by the presence of the pulp horn, which is larger than in the previous stage.   (b) The root length is less than the crown height. Molars:   (a) Initial formation of the radicular bifurcation is seen in the form of either a calcified point or a semi-lunar shape.   (b) The root length is still less than the crown height.
F	Uniradicular teeth:   (a) The walls of the pulp chamber now form a more or less isosceles triangle. The apex ends in a funnel shape.   (b) The root length is equal or greater than the crown height. Molars:   (a) The calcified region of the bifurcation has developed further down from its semi-lunar stage to give the roots a more definite and distinct outline with funnel shaped endings.   (b) The root length is equal to or greater than the crown height.
G	The walls of the root canal are now parallel and its apical end is still partially open (distal root in molars).
H	(a) The apical end of the root canal is completely closed. (Distal root in molars). (b) The periodontal membrane has a uniform width around the root and the apex.