Radiographic Assessment of Bone Healing Using Cone-beam Computed Tomographic Scans 1 and 5 Years after Apical Surgery

The objective of this long-term study was to evaluate radiographic healing in cone-beam computed tomographic (CBCT) scans taken 1 and 5 years after apical surgery.

In the context of a prospective clinical study, postsurgical CBCT scans were taken 1 and 5 years after apical surgery. Three calibrated observers independently assessed buccolingual CBCT images oriented along the longitudinal axis of the treated roots. Radiographic periapical healing was categorized as "fully, partially, or not healed" for each of the following study parameters: the resection plane, the cortical plate, the apical area, and the overall bone healing. The analysis included the interobserver agreement (Fleiss kappa values), the comparison of 5- and 1-year ratings, and the changes of healing categories from 1-5 years (McNemar-Bowker tests). Data were analyzed statistically for the detection of significant differences.

CBCT images of 41 teeth (in 41 patients) with 47 treated roots were evaluated. At 5 years, all studied parameters had higher rates of fully healed cases compared with the rate at 1 year. The resection plane and apical area parameters each were judged in 72.3% as fully healed at 5 years, whereas the cortical plate and overall bone healing parameters showed clearly lower fully healed rates (42.6% and 38.3%, respectively). Fully healed cases at 1 year remained so at 5 years in 87.5%-100% depending on the study parameter.

This 5-year CBCT follow-up study of apical surgery showed a marked improvement of radiographic healing from 1-5 years but to a varying degree regarding the different study parameters. Although new hard tissue formation at the resection plane and within the former apical defect was advanced in most cases at 5 years, the reestablishment of the cortical bone plate clearly lagged behind.