TO CULTURE OR NOT TO CULTURE?

Abstract The results of root canal therapy in 2,335 teeth after 6 months and 706 teeth after 2 years were studied statistically in an attempt to uncover a significant relationship between success of repair in teeth with and without areas of rarefaction, positive or negative cultures, method of filling canals, and other variables. 1. 1. Repair was successful in 82 per cent of the teeth in all categories. 2. 2. Among the root canals of teeth which in the previous visit had yielded a negative culture, 16.6 per cent yielded positive cultures immediately prior to filling of the canal. 3. 3. On the basis of roentgenographic evidence alone, the prognosis for successful repair was less favorable in teeth with areas of rarefaction, regardless of the bacteriologic status of the root canal (88.8 per cent success in teeth without areas of rarefaction, 77 per cent success in teeth with such areas). 4. 4. There was no statistically significant difference between success of repair in teeth yielding positive or negative cultures prior to filling. 5. 5. The lateral-condensation methods of filling canals yielded slightly better results than the single-cone method, but the difference was not statistically significant in all groups. 6. 6. Overfilling of the root canal gave the worst percentage of success (69 per cent), and canals filled flush with the apex showed the best results (87.4 per cent success). 7. 7. A 2 year follow-up gives a more significant evaluation of success than a 6 month follow-up in teeth without areas of rarefaction. In teeth with areas of rarefaction a 6 month follow-up period is as reliable as a follow-up period of 1 to 2 years after treatment for evaluation of success. 8. 8. Differences in successful results may be due to an individual investigator's technique of debridement and pus evacuation, filling, and diagnosis, as well as other factors, but are not based on culture results. 9. 9. Differences in degree of success in this study were dependent upon roentgenographic interpretation and not on other clinical factors.