The potential of periodontal pocket formation associated with untreated accessory root canals.
 Teeth that were to be extracted because of periodontic-endodontic involvement, in six patients, were treated by hemisection or root amputation.
 The roots were processed histologically.
 All cases showed the presence of accessory root canals with remnants of pulpal tissue, bacteria, and necrotic debris.
 It was demonstrated in the cases studied that residual necrotic tissue in untreated root canals can result in periradicular pathosis.
 We may speculate that if the inflammatory process persists and drainage results via the sulcus, in time, plaque and then concretions may develop.
