Gustafson's method used for age estimation of the tooth includes all except -
Gustafson's method includes :

(i) Attrition, 
(ii) Paradentosis,
(iii) Secondary dentin formation,
(iv) Cementum apposition,
(v) Root resorption and
(iv) Transparency of the root.
Primary dentition
Root resorption
Root transparency
Attrition