Pre-operative assessment

Radiographic Analysis and Case Selection

Periapical radiography establishes baseline morphology, but CBCT is the imaging modality of choice for surgical planning. Three-dimensional reconstruction permits accurate assessment of: root length and angulation; the position and size of the periapical lesion; cortical plate thickness and fenestrations; proximity to the maxillary sinus, inferior alveolar nerve, mental foramen, or adjacent root apices; and the position of the mental foramen (particularly for mandibular premolars). Confirm the adequacy of existing root canal treatment and document the clinical rationale for surgery rather than retreatment.

Pre-operative preparation

Patient Preparation and Anaesthesia

Obtain full informed consent documenting risks including post-operative swelling, bruising, paraesthesia, oro-antral communication (maxillary cases), and the possibility of tooth loss. Prescribe pre-operative chlorhexidine gluconate rinses (0.2%, twice daily for 3–5 days) to reduce oral bacterial load. Administer local anaesthetic — infiltration or nerve block as appropriate — using a vasoconstrictor to achieve haemostasis and improve visualisation. Bupivacaine 0.5% with 1:200,000 adrenaline for prolonged anaesthesia is appropriate for complex cases. Allow a minimum of 10 minutes for full vasoconstriction to take effect before incision.

Flap elevation

Mucoperiosteal Elevation and Retraction

Elevate the full-thickness flap using a sharp periosteal elevator, working from the releasing incision toward the lesion to prevent tearing. The periosteum must be fully released to allow passive retraction without tension on the flap margin. Position the retractor on sound cortical bone, not on the elevated flap, and keep it static throughout the procedure to avoid repeated microtrauma to the periosteum. Secure haemostasis of the surgical field using a sterile epinephrine-impregnated pellet or surgical sponge prior to commencing osteotomy. Apply Alustat haemostatic gel (aluminium sulphate) if localised significant soft tissue bleeding is encountered which is not amenable to non chemical strategies.

Root-end resection

Root-end Resection and Inspection

In most cases resect a minimum of 3 mm of root end using a fine-tipped surgical bur at 90° to the long axis of the root where anatomy permits. A 90° bevel minimises the exposed dentinal tubule cross-sectional area and reduces the incidence of apical leakage compared to bevelled resections. Following resection, inspect the cut surface under high magnification (×16–×25) using a microendoscopic inspection mirror (Size 0 or dedicated microsurgery mirror). Examine for: untreated canals or isthmi; root cracks (using methylene blue or Canal Seek stain); the quality of the existing root-end seal; and the relationship of the cut surface to the lateral canal anatomy revealed by CBCT. Document all findings and photograph the resected surface where possible.

Apical obturation

Root-end Filling with Bioceramic Material

The root-end cavity must be thoroughly dried prior to placement of the filling material. Premixed bioceramic materials — tricalcium silicate-based putties (e.g. One-Fil PT) and injectable bioceramic sealers — are the current materials of choice for root-end filling. They offer superior biocompatibility, antimicrobial activity, and sealing ability compared to amalgam or intermediate restorative material (IRM). Deliver the material using a microscope paste carrier or micro-applicator to precisely load the retroprep cavity without contaminating the surgical field. Condense with a micro-plugger (Prexo or equivalent) to ensure complete adaptation to the cavity walls, with particular attention to the isthmus region and any lateral extensions of the preparation. Remove excess material from the cut surface immediately. Under magnification, confirm there are no voids, and that the material is flush with or slightly proud of the resected root face.

MTA and 45 degree angled resection compared to 90 degree resection good haemostatic control and one-fil PT bioceramic putty.

Suturing

Flap Repositioning and Suturing

Microsurgical suturing technique is essential for primary wound healing. Resorbable monofilament 5-0 or 6-0 sutures are appropriate for releasing incisions; non-resorbable monofilament (6-0 or 7-0 nylon, polypropylene) is preferred at the papillary level for sulcular or papilla-base flaps, providing superior tissue approximation and reduced inflammatory response compared to braided sutures. Place interrupted or sling sutures at each interdental papilla first to key the flap margin, then close the vertical releasing incisions. Avoid excessive suture tension. Confirm complete coaptation of the flap margin under magnification and apply firm digital pressure for 2–3 minutes post-suture placement. Provide written post-operative instructions and prescribe appropriate analgesia.