Category Archives: Principles of Endodontic Surgery

Principles of Endodontic Surgery

CHAPTER OUTLINE

 DRAINAGEOF AN ABSCESS
PERIAPICALSURGERY
Indications
Anatomic Problems
Restorative Considerations
Horizontal Root Fracture
Irretrievable Material in Canal
Procedural Error
large Unresolved l,esions After Root Canal
Treatment •
Contraindlcations (or Cautions)
Unidentifie.d Cause of Treatment Failure
When Conventional Root Canal Treatment is
Possible
Simultaneous Root Canal Treatment and Apical
Surgery .
Anatomic Considerations
Poor Crown and Root Ratio
Medical (Systemic) Complications
Surgical Procedure
Flap Design
Semilunar Incision
Submarginal Incision
Full Mucoperiosteal Incision
Anesthesia
Incision and Reflection
Perlaplcat Exposure
Curettage
Root End Resection
Root End Preparation and Restoration
Root End-Filling Materials

Irrigation .
Radiographic Verification
Flap Replacement and Suturing
Postoperative Instructions
Suture Removal and Evaluation
CORRECTIVESURGERY
Indications
Procedural Errors
Resorptive Perforatiow;
Contraindications
Anatomic Considerations
Location of Perforation
Accessibility
Co~derations
Surgical Approach I .
Repair Material
Prognosis Su’r.gICal Procedure
HEALING
RECALL
ADJUNCTS
Light and Magnification Devices
Surgical Microscope
Fiber Optics
Guided Tissue Regeneration
Bone Augmentation
WHEN TO CONSIDER REFERRAL
Training and Experience
Determinlnq the Cause of Root Canal Treatment
Failure
Surgical Difficulties

Endodontic surgery the management or provenion of j1crir;ldic.ular pathosis by J sl~igi~al app.roa.ch. In ‘enl’r JI. this Includes abscess drainage, periaplcal ur ~t’r.· COrTC, tive surgery, intentional replantation, and rtl( n:I1I()\ ell dlo.\ 17-1). lIT en” hil~ tradttlonally been an important part of end t anti.. treatment. However, until recently there was lit; l’ research on indications and contraindications, techruques, success and failure (i.e., long-term prognosis), wound healing, and materials and devices to augment procedures. Because of this lack of information, many
surgeries were performed for the wrong reasons, such as the routine correcting of failed root canal treatment, removing of large lesions believed to be cysts, or the performing of single-visit root canal treatment: Indeed, on occasion, a surgical approach is clearly indicated, but [ew situations exist in which sl/rgery is required. Other modalities, such as root canal treatment or retreatrnent, may be preferred. However, when surgery is required, it must adhere to basic endodontic principles, that is, the assessing and  obtaining of adequate debridement and obturation of the. canal or canals.’

Root canal treatment is generally a successful procedure if the. problem is accurately diagnosed and careful technique Is used. A common misconception is that if conventional root canal treatment fails, surgery is indcated forcorrection. Usually this is not true’; most failures are better managed by retreatment.? At other times surgery is necessary to correct a failure or, for other reasons, may be the only alternative to extraction. The purpose of this chapter is to present the Indications and contraindications for endodontic surgery, the diagnosis and treatment planning, and the basics of endodontic surgical techniques. Most of the procedures presented should ‘be performed by specialists, or on occasion, by experienced generalists. However, the general dentist must be skilled in diagnosis and treatment planning and able to recognize which procedures are indicated
in particular situations. When a patient is to be referred to a specialist for treatment, the general dentist must have knowledge sufficient to describe the surgical procedure. In addition, the generalist should assist in the follow-up care and long-term assessment of treatment outcomes.

The procedures discussed in this chapter are drainage of an abscess, apical (l.e., perpendicular) surgery, and corrective SURGERY.

Contraindications (or Cautions)

Contraindications (or Cautions)

if othe options are available, periapical surgery may no! referred choice (Box] 7-3).Cllidcnti(ictf CUIIW IIf trcut nunt fuirWt Relying on surgery to try to correct all root canal treatment failures could be .labeled indiscriminate. An important consideration is to first, identify the cause of filllure.vthcn S(,COllcC design an appropriate corrective treatment plan. Usually. retreatrnent is indicated and will :’i\”(‘ t he best chance 01 success. Surgery to correct a treat men! failure’ for which the cause can-rot be  dentified is often llm”L”n·~••Iul. Surgical managenient at all peri~pical jldtho\l”‘> .. large .pcri-

FIG. 17-3 A, Very small canal· (i.e., calcific metamorphosis) with pulp necrosis and apical pathosis. Canal could not be located with occlusal access. B, Apical resection and root end retrograde amalgam ~~~i~~ . FIG.

FIG. 17-3 A, Very small canal· (i.e., calcific metamorphosis) with pulp necrosis and apical pathosis.
Canal could not be located with occlusal access. B, Apical resection and root end retrograde amalgam
FIG.

FIG. 17-4 A, Irretrievable fractured post and apical pathosis. B, Root end resection and filling with amalgam to seal in irritants, Hkelyfrom coronal leakage. C, Regeneration of bone is evident after several months; prognosis is good.

FIG. 17-4 A, Irretrievable fractured post and apical pathosis. B, Root end resection and filling with
amalgam to seal in irritants, Hkelyfrom coronal leakage. C, Regeneration of bone is evident after several
months; prognosis is good.

FIG. 17-5 A, Horizontal root fracture, with failed attempt to treat both segments. 8, Apical segment is removed surgically and retrograde amalgam placed. C, Healing is complete after 1 year.

FIG. 17-5 A, Horizontal root fracture, with failed attempt to treat both segments. 8, Apical segment
is removed surgically and retrograde amalgam placed. C, Healing is complete after 1 year.

apical lesions, or both is often not necessary, because they will resolve after appropriate root canal treatment. This includes  sions that may be. cystic; these also usually heal after root canal treatment. When conventional root canal treatment is possible. In most situations orthograde conventional root canal treatment is preferred (Fig. 17-11′ on page 391).4 Surgery is not indicated just because debridement and obturation are in the same visit, although there has been a long-held, incorrect notion that single-visit  hould be accompanied by surgery, particularly if a periradicular lesion is present. Simultaneous root canal treatment and apicalurgery.

Few situations occur in which simultaneous root canal therapy and apical surgery is indicated. Usually, an approach that includes both of these as a single procedure has no advantages. It is preferable, and. likely will result in better success, to perform only the conventional treatment without the adjunctive apical surgery. Another consideration is posttreatment symptoms. The level and incidence of pain after apical surgery is higher as compared with root canal treatment.” Anatomic considerations. Most oral structures do not interfere with a surgical approach but must be considered, An example is the maxillary sinus, whic may become exposed. Creating a sinus opening is neither unusual nor dangerous. However, caution is necessary to not introduce foreign objects into the opening and to remind the patient not to exert pressure by f~cibly blowing the nose until the surgical wound has healed (in 1 to 2.weeks). Bony structures generally do not contraindicate surery, with the exception of the external oblique ridge rer the mandibular second and third molars. In most this structure prevents adequate access to the ro ble. Other approaches, such as intentional replantation(Fig. 17-12 on page 392), may be indicated. The zygomatic buttress may inhibit access to maxillary molar apices. A prominent chin creates a shallow vestibule with limited access to mandibular anteriors. The mental foramen is of concern but is easily avoided by identifying its position radiographically and during flap reflection. Poor crOW1Iand root ratio. Teeth with very short roots have compromised bony support and are’ poor candidates for surgery; root end resection in such cases may compromise stability. However, shorter roots may support a relatively long crown if the  urrounding cervical periodontium is healthy (see Fig. ’17-5) . .\fcdiwi (‘Iptell/ic) complications, The general health and condition of the patient are always. essential considerations. No specific contraindications for endodontic surgery exist that would not be similar to those for other types of oral surgical procedures.

Indications

Indications

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    11

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

 11

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.

PERIAPICAL SURGERY

PERIAPICAL SURGERY

Periapical (i.e., periradicular) surgery includes resection of a portion of the root that contains undebrided or unobturated (or both) canal space. It can also involve reverse filling and sealing of the canal when conventional root canal treatment is not feasible. It is often performed inconjunction with apical curettage for reasons explained  later in this chapter.

DRAINAGE OF AN ABSCESS

DRAINAGE OF AN ABSCESS

Drainage releases. purulent or hemorrhagic transudates and exudates from a focus of liquefaction necrosis (i.e., abscess). Draining the abscess relieves pain, increases circulation, and removes a potent irritant. The abscess may
be confined to bone or may have eroded through bone and periosteum to. invade soft tissue. Managing these i:’.lraoral or extraoral swellings by incision for drainage is reviewed in Chapters IS and 16. An abscess in bone may be drained by two methods: One is by opening into the offending tooth to obtain I .nage through the canal; ‘the abscess often docs not

BOX t1-1
Categories of Endodontic Surgery Abscess drainage Periapical surgery Hemisection/root amputation Intentional replantation Corrective surgery BOX 17-2  Indications for Periapical Surgery Anatomic problems preventing complete debridement/obturation Restorative considerations that compromise treatment Horizontal root fracture with apical necrosis Irretrievable material preventing canal treatment or retreatment  Procedural errors during treatment Large periapical lesions that do not resolve with root canal treatment commurucate with the apex. The- other suggested approach to manage an abscess in bone is called trephination.This is done by attempting to create a pathway with a bur or rotary instrument through gingiva and cortical bone, directly into the abscess. This approach is of questionable effectiveness.!