The aim of the study was to evaluate the effect of Piezosurgery and Trephine bur as cutting tools on post-operative sequelae including pain and swelling following guided endodontic microsurgeries.

Materials and Methods: Twenty healthy male patients aged between 18 and 45 years old were selected in the study. Mandibular first molar teeth with failed non-surgical treatment or re-treatment due to iatrogenic errors at the apical 3mm of the mesial root canal including canal ledging, zipping and transportation, root perforation, separated instrument, and canal calcification were selected. Piezosurgery assisted cavity preparation and root-end resection were performed in Groups I and II, and Trephine bur assisted cavity and root-end resection was performed in Groups III and IV. An apical curettage was performed and the over-extended objects such as separated instruments or gutta percha were removed. The PRF clots was placed inside the bone cavity in groups I and III while the bone cavity was kept for 2 min to allow the blood clots to be formed in groups II and IV. The degree of pain and swelling were recorded for five days every 24, 48, 72, 96, and 120 hours postoperatively.

Inclusion Criteria:

Mandibular first molar teeth were selected according to specific inclusion criteria including:

1. Teeth presented with failed non-surgical treatment or re-treatment. Failure is due to iatrogenic errors at the apical 3mm of the mesial root canal including canal ledging, zipping and transportation, root perforation, separated instrument and canal calcification.
2. Teeth presented with normal pocket depth ranges from 1 to 3mm, up to grade II tooth mobility.
3. Teeth presented without periapical radiolucency (Class A) or with periapical radiolucency not more than 1 mm in diameter both mesiodistally and buccolingually (Class B) according to the preoperative endodontic microsurgical classification of teeth.
4. Teeth presented with non-fused mesial and distal roots and the mesial roots are range from 10 to 15 mm. in length, Type III root canal configuration (Two canals run separately from orifice to apex). The root canal curvature angle was measured using the Weine technique to be not less than 160° in both directions buccolingually and mesiodistally.
5. At the apical 3 mm of the mesial radiographic root apex, the distance from the outer surface of the buccal cortical plate of bone to the buccal side of the mesial root is 1.5 mm (Depth I). The buccolingual dimension of the mesial root is 7 mm mm (Depth II). The distance from the lingual surface of the mesial root to the outer surface of the lingual cortical plate of bone is 3.5 mm. (Depth III).