EXAMINATION OF EXTERNAL APICAL ROOT RESORPTION WITH SCANNING ELECTRON-MICROSCOPY

External apical root resorption may be evident histologically bur not visible radiographically until it is advanced. If working length is de termined without considering this resorption, overinstrumentation or o verfilling may occur. Objective. This study used scanning electron mic roscopy to examine the appearance and to compare the incidence of exte rnal apical root resorption in 40 teeth with differing pulpal and peri apical diagnoses. Study design, After extraction, 46 roots were sectio ned horizontally 6 mm from the anatomic apex and prepared for scanning electron microscopy examination. Photomicrographs were scored by two blinded independent examiners. Apical resorption was categorized as: n one, partial, or complete. Presence or absence of a funneling appearan ce of the resorption was also recorded. Results. Kruskal Wallis showed a significant difference in resorption between groups; teeth with irr eversible pulpitis/normal periapex had the least resorption. Duncan's multiple range test found radiographic apical lesions to have more res orption than those without lesions, teeth with necrotic pulps had more resorption than those with vital pulps. Conclusion. Pulp necrosis wit h radiolucent apical pathosis is more likely to demonstrate resorption .