Apicoectomy

Abstract: von Arx T. Frequency and type of canal isthmuses in first molars detected by endoscopic inspection during periradicular surgery. International Endodontic Journal, 38, 160‐168, 2005. Aim To analyse the occurrence of canal isthmuses in molars following root-end resection. Methodology The material consisted of 56 mandibular and 32 maxillary first molars subjected to periradicular surgery. Based on radiographic, clinical, as well as intraoperative status, only roots with associated pathological lesions were treated. In total, 124 roots were resected (80 mandibular and 44 maxillary molar roots). The cut root faces were inspected with a rigid endoscope following apical root-end resection. The number of canals as well as the presence and type of canal isthmuses were recorded. Results In maxillary first molars, 76% of resected mesio-buccal roots had two canals and an isthmus, 10% had two canals but no isthmus, and 14% had a single canal. All disto-buccal and palatal roots had one canal. In mandibular first molars, 83% of mesial roots had two canals with an isthmus. In 11%, two canals but no isthmus were present, and 6% demonstrated a single canal. Sixty-four per cent of distal roots had a single canal and 36% had two canals with an isthmus. Conclusions This clinical study during periradicular surgery and intraoperative endoscopic examination of first permanent molars found a high frequency of canal isthmuses at the resection level. Endoscopic inspection also demonstrated that none of the isthmuses were filled, emphasizing the difficulty of orthograde instrumentation and root filling of canal isthmuses.

Abstract: Aim The aim of the present study was to evaluate the short-term response of periradicular tissues to MTA when used as a root-end filling material in ideal tissue conditions Methodology The experimental procedures were performed on the healthy teeth of dogs Pulps were removed and root canals prepared and filled with gutta-percha and sealer At the same session, buccal mucoperiosteal flaps were reflected and the root ends resected MTA or IRM were used as root-end filling materials The periradicular tissue reactions were evaluated histologically from 1 to 5 weeks Hard tissue formed on the MTA surface was further examined by scanning electron microscopy Results The most characteristic tissue reaction to MTA was the presence of connective tissue after the first postoperative week Inflammation was seen occasionally Early tissue healing events after MTA root-end filling were characterized by hard tissue formation, activated progressively from the peripheral root walls along the MTA-soft tissue interface In contrast, hard tissue was not seen over the IRM root-end filling Conclusions MTA is a biocompatible material that stimulates periradicular tissue repair at the root-end situation; however, the nature of the newly formed tissues requires further elucidation