Anatomical crown-root-ratio: A proxy to root length determination in rural endodontic practice

Abstract

Background: Power supply has become increasingly erratic.    In the rural communities it may be completely lacking, making radiography impossible. Tooth multiplication factor is a viable option to periapical radiographs in endodontic treatment.
Methodology: A total of 120 upper central permanent incisor teeth were selected from 2,765 extracted teeth used for teaching of oral biology to dental students. These teeth were collected over 10-year period. The permanent central incisors were sorted using size, shape, colour and specific central incisor indices as parameter.   Tooth location to the left or right was not of prime importance.
Anatomical root-crown-ratio was determined using calibrated card board paper, simple ruler and Vernier calipers. One hundred and twenty upper permanent central incisors were randomly divided into six groups (A to F) before measurement of crown and root lengths.
Result: Crown-root-ratio was 1:1.375.   Every millimeter of crown is equal to1.375mm of root. Where (x) is the crown length. Therefore an anatomical crown length of 10mm will have an endodontic root length of 13.75mm given a total canal length of 23.75mm which is in tandem with reported average maxillary central incisors average canal length of 22mm – 23.8mm    

Conclusion: Tooth multiplication factor is recommended for trial especially in this power situation, especially worse in rural communities