The purpose of the rpesent study was to compare tooth mortality of root-resected molars with that of root-filled, single-rooted teeth. Survival rates were 68% for root-resected molars and 77% for root-filled single-rooted teeth over a 10-year period. This difference was not statistically significant. Ten-year survival of root-r esected molars in patients with radiographic attachment loss in single-rooted teeth of greater than 6 mm was 56%, while survival was as high as 89% for root-resected molar patients with radiographic attachment loss in single-rooted teeth less than or equal to 6 mm. In conclusion, the prognosis of root-resection is not poorer than the prognosis of single-rooted teeth with an equal susceptibility to periodontitis, if endodontic conditions and maintenance care are optimal.