Root canal enlargement after endodontic treatment

TITLE: ROOT CANAL ENLARGEMENT AFTER ENDODONTIC TREATMENT OBJECTIVE: To quantify mesio-distal canal enlargement after endodontic instrumentation. METHODS: The study sample consisted of 39 patients, 14 male and 25 female, with endodontic necessity in 12 anterior and 27 posterior teeth. Incisors, canines, single root pre-molars and lower distal canal molars (all futures abutments) were evaluated. Standardized parallel-technique radiographs for each of them were taken. The initial taken before any endodontic procedure and the final radiograph was taken after endodontic treatment was finished. Crown Down endodontic technique was used and the teeth were classified in two groups depending on the endodontic instrumentation: manual (n=24) using 30 diameter K file (Flexofile®, Dentsply) and rotary (n=15) using F3 diameter Universal Rotary Instruments (ProTaper® Dentsply). All measurements were made by one blind calibrated operator (kappa=0.8) using SIDEXIS XG® 1.4 version (Sirona Dental Systems GmbH®). Measurements of the mesio-distal distance of root canals in their cervical and middle thirds were compared before and after the intervention. The data was analyzed with Stata 10.0 program. Results were expressed in averages and t-test was used. RESULTS: The average initial distance for cervical-third was 1.13mm and 0.65mm for middle-third. The average post-treatment distance was 1.7mm for cervical and 1.12 for middle-third. Results show a mesio-distal root canal distance increase of 150.4% for the cervical third and 172.3% for the middle third (p< 0,001).No statistical significant differences were found between manual or rotary technique on root canal enlargement (p>0.627). CONCLUSION: The Crown Down instrumentation technique generates a significant enlargement of mesio-distal root canal dimensions for the cervical and middle third regardless the instrumentation method.