The success of apical surgery varies considerably, depending on the reason for and nature of the procedure. With failed root canal tment, often retreatment is not possible or a better result cannot be achieved by a coronalpproach.’ If the cause of the failure cannot be identified, surgical exploration may be necessary (Fig. 17-1). On occasion an unusual entity in the periapical region requires surgical removal and biopsy for identification (Fig. 17-2). Those indications for periapical surgery are discussed in the following sections (B9X 17-2), Calcifications or other block- _ ages, severe root curvatures; or onstricted canals [i.e., calcific
FIG. 17-1 Surgical exploration. A, Periradicular’lesion on mesial root may be caused by perforation, incomplete debridement (lateral and apical), or vertical root fracture. B, Visualization after flap reflection shows vertical root fracture (arrow); root must be removed or tooth extracted. (Courtesy of Dr. L. Batdossori-Cruz, Universitv of Iowa.) r both (Fig. 17-3). Because a canal is always present (even if very small), failure to debride and obturatemay lead to failure. . lthough the outcome may be estionable, it is preferable to attempt conventional root canal treatment or retreatment before apical surgery.’ If this is not possible, rnovlng or resecting’ the’ un instrumented and unfilled portion of the root and placing a root end filling mal; be necessary. . Restorative ‘ ‘. Root canal treatment may be risky because of problems that may occu from attempt-: ing access through a restoration, such as through a crown . on a mandibular incisor. An opening could compromise retention of the restoration or perforate the root. Rather than attempt the root canal treatment, root resection and tot-end filling may he preferred to seal in irritants. A common requirement for surgery is failed treatment on a tooth that has been restored with a post and core (Fig. 17-4). Many posts are difficult to remove or may cause root fracture during removal.i mot ‘frd ture. Occasionaijy,.after a traumatte root fracture, the rical segment undergoes pulp necrosis. Because this cannot be predictably treated from a coro al approach, the apical segment is removed surgt- .cally after root canal ‘treatment of the coronal portion (Fig. 17-5). II rctrieiahi ntutvriai ill . Canals are occasionally blocked by objects such as separated struments (Fig. 17-6), restorative materials, segments of posts, or Contraindications (or Cautions) for Periapical SurgeryUnidentified cause of root canal treatment failure When conventional root canal treatment is possible Combined coronal treatmentiapical surgery i!l When retreatment of a treatment failure is possible II Anatomic structures (e.q., adjacent nerves and vesj .sels) are in jeopardy , t.I Structures interfere with access and visibility a Compromise of crown root ratio D Systemic complications (e.q., bleeding disorders) other foreign objects. If evidence of apical pathosis is found, those materials must be removed surgically, usuallywith a portion of the root (Fig. -7) .. Procedural error.’ Separated instruments, ledging, gross overfills, and perforations (Figs: 17-8 and 17-9 on pages 388 and 389, respectively) may result in failure. Although overfilling is not in itself an indication for removal.of the material, surgical correction is frequently necessary in these situations. Large ‘(‘cI lesions artl
fiG. 17·2 Surgical removal-of pathosis. A, Pulp is responsive; this indicates that radiolucent lesion is not endodontic (i.e., pulpal) in origin. B, Because roots must be resected while removing the lesio root canal treatment is performed. C, Distal root is resected and lesion is excised. D, Biopsy shows this to be an ossifying fibroma decompression and. not curettage, which may damage adjacent structures (rig. 7-0 on page 390). Often, decompression alone is” sufficient to manage these lesions; surgical correction (i.e., removal) is unnecessary.