Surgical vs. Closed Extraction Techniques
Frank J.M. Verstraete, DrMedVet, MMedVet, DAVDC, DECVS
A tooth is held in place by the periodontal ligament fibers, connecting the alveolar bone to the cementum. The basis of the extraction procedure is to stretch and sever these fibers in order to loosen the tooth with minimal trauma to the surrounding tissues. In a simple or closed extraction the periodontal ligament is severed using dental elevators or luxators, and the extraction can be completed without the need for sectioning the tooth, creating a mucogingival flap, or removing alveolar bone. The latter procedures form part of a surgical extraction. It is important to anticipate or to recognize early in the extraction procedure the necessity for a surgical extraction. A surgical extraction is indicated if a simple extraction is unlikely to achieve the objective of removing the tooth completely and with minimal trauma to the surrounding tissues. This may be the case because of the size of the tooth (e.g., canine tooth), an anatomical abnormality (e.g., dilaceration) or limited accessibility (e.g., fractured root tip).
Pre-extraction radiographs of teeth to be removed are indicated to confirm the diagnosis, to allow visualization of the root morphology and to ascertain the presence of root resorption or root ankylosis. Post-extraction radiographs are recommended to confirm that no root tips were left behind and to document possible alveolar bone injury due to the extraction procedure.
Good exposure and visibility make tooth extraction that much easier to perform. Proper positioning, good lighting, irrigation and suction are all factors affecting visibility. Aseptic technique is recommended for surgical extractions; removing dental calculus and subgingival débris, and subsequently flushing the mouth with a suitable antiseptic solution is indicated prior to a surgical extraction.
In general, a mucoperiosteal pedicle flap is elevated using a periosteal elevator and reflected, exposing the buccal alveolar bone; alternatively an envelope or triangle flap may be used. If a dental drill unit is available, an osteoplasty bur is mounted on the high-speed handpiece or on the straight surgical handpiece. Using constant irrigation, the proximal part of the buccal alveolar bone is drilled away; this procedure is called an alveolotomy or partial alveolectomy. While the bone is removed, the mucogingival flap is retracted using stay sutures or a retractor. It is important that the buccal flap is wider than the bony defect, so that the suture line will be supported by undamaged bone. The dental elevators can now be inserted more deeply into the periodontal space. If the whole root cannot yet be loosened, more alveolar bone should be removed. Final delivery may be achieved with forceps. Following an alveolectomy, the empty alveolus is cleared of any débris. Sharp bony edges preventing smooth soft tissue closure can be removed using an osteoplasty bur, bone rongeur or small file; this procedure is called alveoloplasty. The mucogingival edges are approximated and sutured. Monofilament synthetic absorbable suture material is recommended. Care should be taken not to penetrate the maxillary recess, the infraorbital canal or the mandibular canal.
If, because of periodontitis, significant alveolar bone resorption has taken place, two-rooted and three-rooted teeth can be lifted out intact after thorough loosening of the periodontal attachment. In most cases however, it is better to cut the tooth into two or three parts, thus creating the equivalent of two or three single-rooted teeth. After loosening the gingiva from the crown and retracting it somewhat (an envelope flap), the furcation of the root is usually visible. In order to achieve a better exposure of the furcation of the root, 2-3 mm of the alveolar margin may be removed. If necessary, a full-size buccal flap and alveolotomy can be created. If a dental drill unit is available, the tooth is easily sectioned using a cylindrical or taper bur; sectioning preferably starts at the furcation. Following sectioning, a dental elevator can be used for horizontal leverage. The elevator is introduced horizontally between the two segments of a two-rooted tooth and is rotated through a small angle and held for a few seconds, allowing the periodontal fibers to stretch. Gradually, the tooth is delivered by progressive tearing of periodontal fibers and levera.