The efficacy of supplementary sonic irrigation using the EndoActivator® system determined by removal of a collagen film from an ex vivo model.

AIM: To evaluate the efficacy of sonic irrigation (EndoActivator® ) using various polymer tips and power settings in a stained collagen ex vivo model. METHODOLOGY: The root canals of fifty human, straight single-rooted extracted teeth were prepared to size 40, .08 taper. The roots were split longitudinally; stained collagen applied to the canal surfaces, photographed and re-assembled. The canals were subjected to syringe without supplementary (group 1, n = 10) or with supplementary sonic (groups 2-5, n = 10) irrigation. EndoActivator® tip sizes (size 15, .02 taper for groups 2 and 3; size 35, .04 taper for groups 4 and 5) and power settings (low for groups 2 and 4; high for groups 3 and 5) were tested. After irrigation, the canals were re-photographed and the area of residual stained collagen was quantified using the UTHSCA Image Tool program (Version 3.0). The data were analysed using Wilcoxon signed rank test and general linear mixed models. RESULTS: Supplementary sonic irrigation using EndoActivator® resulted in significantly (P < 0.0001) less residual collagen compared with syringe irrigation only. Agitation of irrigant using the large EndoActivator® tip with high power resulted in significantly less (22.4% - 29.5%) residual collagen compared to other combinations (large tip/low power P = 0.001; small tip/low power P = 0.01; small tip/high power P = 0.04). There was no significant difference amongst the latter three groups (P > 0.5). CONCLUSIONS: Supplementary sonic irrigation using the EndoActivator® system was significantly more effective in removing stained collagen from the canal surface than syringe irrigation alone. EndoActivator® used with large tip (size 35, .04 taper) and high power setting in size 40, .08 taper canals was more effective than other combinations.

A prospective study of the factors affecting outcomes of nonsurgical root canal treatment: part 1: periapical health.

AIM: To investigate the probability of and factors influencing periapical status of teeth following primary (1°RCTx) or secondary (2°RCTx) root canal treatment. METHODOLOGY: This prospective study involved annual clinical and radiographic follow-up of 1°RCTx (1170 roots, 702 teeth and 534 patients) or 2°RCTx (1314 roots, 750 teeth and 559 patients) carried out by Endodontic postgraduate students for 2-4 (50%) years. Pre-, intra- and postoperative data were collected prospectively on customized forms. The proportion of roots with complete periapical healing was estimated, and prognostic factors were investigated using multiple logistic regression models. Clustering effects within patients were adjusted in all models using robust standard error. RESULTS: proportion of roots with complete periapical healing after 1°RCTx (83%; 95% CI: 81%, 85%) or 2°RCTx (80%; 95% CI: 78%, 82%) were similar. Eleven prognostic factors were identified. The conditions that were found to improve periapical healing significantly were: the preoperative absence of a periapical lesion (P = 0.003); in presence of a periapical lesion, the smaller its size (P ≤ 0.001), the better the treatment prognosis; the absence of a preoperative sinus tract (P = 0.001); achievement of patency at the canal terminus (P = 0.001); extension of canal cleaning as close as possible to its apical terminus (P = 0.001); the use of ethylene-diamine-tetra-acetic acid (EDTA) solution as a penultimate wash followed by final rinse with NaOCl solution in 2°RCTx cases (P = 0.002); abstaining from using 2% chlorexidine as an adjunct irrigant to NaOCl solution (P = 0.01); absence of tooth/root perforation (P = 0.06); absence of interappointment flare-up (pain or swelling) (P =0.002); absence of root-filling extrusion (P ≤ 0.001); and presence of a satisfactory coronal restoration (P ≤ 0.001). CONCLUSIONS: Success based on periapical health associated with roots following 1°RCTx (83%) or 2°RCTx (80%) was similar, with 10 factors having a common effect on both, whilst the 11th factor 'EDTA as an additional irrigant' had different effects on the two treatments.