Open or Blunderbuss Apex or divergent roots

The mechanical cleaning & shaping of teeth with blunderbuss canal apex are very difficult if not impossibly orthogratly due to

1- The thin fragile lateral dentinal walls that can fracture during  mechanical filing.

2- The large volume of necrotic debris contained in a wide root canal  is difficult to disinfect.
3- Obturation of wide canal systems requires precise fabrication  of a customized gutta percha cone

4- Moreover, many blunderbuss canals with flaring walls can not be obturated &  sealed by orthograde methods & might require apical surgery & retrograde sealin  of the canal

5- There is danger of splitting of the root during gutta percha  condensation.Thus, Treatment of the immature non-vital anterior teeth with apical pathosis  presents