The flaws in tooth root resorption assessment algorithms: the role of source position.

OBJECTIVES

The purpose of this project was to analyse the effects of X-ray source location on mathematical compensations used in the clinical assessment of external apical root resorption (EARR).

METHODS

Using geometric constructions, governing equations were derived to express the relationships between actual tooth, root and crown lengths, and their image sizes on "before" and "after" radiographs.

RESULTS

Good agreement was found between calculated and published experimental results. More importantly, errors associated with the assessment methods are demonstrated.

CONCLUSION

It is established that root resorption assessment algorithms cannot reliably compensate for the inherent distortions in radiographic evaluations of EARR, even in the best-case scenario of an idealized, precisely characterized, linear tooth.