Table 2. The volume (mm³) of initial root canals (initial canal volume, ICV), after the retreatment technique (canal volume 1, CV1), and the supplementary method (canal volume 2, CV2).

Root canal volumes	Mean ± SD (mm3)	p value
ICV	4.71 ± 1.17a	< 0.01
CV1	5.84 ± 1.39b	< 0.01
CV2	6.03 ± 1.40c	< 0.01

SD, standard deviation.

Different letters indicate a statistically significant difference (p < 0.01).