Root-end resection after filling with single cone technique and bioceramic sealer: an effective way to simplify endodontic surgery?

State of the art endodontic surgery with controlled retrograde procedures may not be feasible in all teeth due to poor access and other technical difficulties. In selected cases, the possibility to perform the sole apical resection without further retrograde manoeuvres might constitute a substantial clinical advantage. The present study compared the filling quality obtained with standard retrograde procedures with that of an alternative technique without retrograde preparation and filling. Methods: Previously published data served for sample size calculation (α=0.05; β=0.20; δ=3.0; σ=1.5). Twelve single-rooted teeth were selected from a pool of freshly extracted teeth, discarding those with aberrant anatomy. Selected teeth of comparable size were decoronated to obtain 12 mm long roots. The canals were scouted with manual files and the working length acquired. After mechanical glide path establishment, canal shaping was performed with HyFlex rotary files up to size 40, .04 taper (500 rpm; 2.5 Ncm). The roots were analysed with a computed microtomography scanner to identify the possible presence of dentine microcracks. Afterwards, all the canals were filled with the single cone technique with dedicated cones and BioRoot RCS bioceramic sealer. After 24 h, the roots were apically resected with a carbide bur 3 mm from the apex. At this point, the roots were randomly assigned to two groups: no retrograde procedures (n=6); standard retrograde ultrasonic preparation and Biodentine filling (n=6). Lastly, the formation of internal and external voids was quantified by means of a second computed microtomographic analysis. The normality of the distribution and the equality of variance of the microtomographic datasets were tested with a Shapiro-Wilk and a Levene test, respectively; then, the volumes measured in the two groups were statistically compared with an independent sample t-test (p=0.05). Results: Minimal voids volumes were observed in both considered groups. In the group entailing standard retrograde procedures, the mean voids volumes were 1.878±1.492 % of the entire canal space, in the group with sole root-end resection 0.823±0.576 %. The difference was not significant (p=0.137). Irrespective of the considered group, the small amounts of detected voids were mainly located inside the sealer. Conclusion: When executable, filling the canal with the single cone technique and bioceramic sealer associated with simple root-end resection appears to provide an effective seal of the endodontic space. In selected cases, such technique could make the need to perform retrograde preparation and filling less imperative.