Table of Contents
Journal of Oral Diseases
Volume 2014, Article ID 157523, 4 pages
Research Article

Reliability of Pederson Scale in Surgical Extraction of Impacted Lower Third Molars: Proposal of New Scale

1Dental School, Aleppo University, Aleppo, Syria
2Al Farabi College of Dentistry, Jeddah 45107, Saudi Arabia
3Al Farabi College of Dentistry, Riyadh 11691, Saudi Arabia

Received 3 April 2014; Revised 29 May 2014; Accepted 4 June 2014; Published 12 June 2014

Academic Editor: Tarek El-Bialy

Copyright © 2014 Mohamed Yasser Kharma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The aim of this study was to evaluate the clinical reliability of the Pederson index in preoperative assessment of the difficulty of surgical removal of impacted mandibular third molars. Pederson index was found to be unreliable predictor of true difficulty with low sensitivity and specificity. A new index (Kharma scale), which takes into consideration the anatomical form of tooth roots, is proposed and evaluated both pre- and postoperatively. The results of the evaluation indicate that the new estimating index is more reliable and accurate measure than Pederson scale.