■ teeth with marginal ridge cracks
■ teeth with mesial or distal probing pocket depths of ≥5 mm
■ periapical diagnosis of chronic apical periodontitis (CAP), suppurative apical periodontitis (SAP) or acute apical abscess (AAA)
Based on these results, the authors created a novel prognostic index (Figure 1) for successful orthograde root canal therapy in cracked teeth, rated from most likely to least likely to succeed:
■ Iowa stage I: no probing pocket depths ≥5 mm; no crack across the distal marginal ridge
■ Iowa stage II: no probing pocket depths ≥5 mm; crack present across the distal marginal ridge; no periapical diagnosis of CAP or SAP or AAA
■ Iowa stage III: no probing pocket depths ≥5 mm; crack present across the distal marginal ridge; a periapical diagnosis of CAP or SAP or AAA
■ Iowa stage IV: ≥1 mesial or distal probing pocket depth ≥5 mm
Of course, standard treatment methods and technology have evolved over the 25 years covered by this study; for example, the endodontist incorporated nickel–titanium instrumentation 10 years after beginning private practice. Overall, the results of this study suggested that root canal treatment in cracked teeth may have a higher rate of success than had been previously reported.
Krell KV, Caplan DJ. 12-month success of cracked teeth treated with orthograde root canal treatment. J Endod 2018;doi:10.1016/joen.2017.12.025.