Effects of Dimensions of Root-End Fillings and Peripheral Root Dentine on the Healing Outcome of Apical Surgery

Objective: The objective of this study was to assess dimensions of root-end fillings (REFs), as well as peripheral root dentine (PRD) and their effects on the healing outcome of apical surgery.
Methods: Cone beam computed tomography (CBCT) scans were utilized to measure the REF length and width and the PRD thickness in 61 roots of 53 teeth 1 year after apical surgery. Measurements were taken in the mesio-distal as well as bucco-lingual directions. The REF alignment with respect to the root axis was also evaluated. In addition, the dimensions of REF and PRD were assessed for possible correlations with the healing outcome. Criteria for determining the healing outcome included clinical and radiographic parameters.
Results: The mean REF length was 2.02±0.52 mm. No significant differences were observed with regard to tooth groups, but one-canal roots had a significantly longer mean REF than two-canal roots (P=0.006). The mean REF widths were 1.14±0.24 mm mesio-distally and 2.61±1.24 mm bucco-lingually. Roots with two canals presented a significantly wider REF (P<0.001) in the bucco-lingual dimension but had a significantly narrower REF in the mesio-distal direction (P<0.001) compared to roots with single canals. PRD measured on average 1.19±0.23 mm at the resection level and 1.44±0.27 mm at the coronal end of the REF. Almost all REFs were perfectly aligned with the longitudinal axis of the roots. With regard to healing outcomes, no correlations were found with REF and PRD values, respectively.
Conclusion: The mean REF length was 2.02 mm. On average, a thickness >1 mm of peripheral root dentine was maintained. The REF or PRD dimensions had no statistical effect on the healing outcome.