By Dr. Joseph K. McCombs
Certain biologic principles govern all living things. These principles were not created but exist as an independent reality. Cecil DeMille, director of the movie, The Ten Commandments, once said, “It is impossible for us to break the law. We can only break ourselves against the law”. Successful surgeons build on these foundational biologic principles to consistently attain great outcomes. Unsuccessful surgeons disregard biology and have many more complications and failed results. It really is that simple. This article will highlight five periodontal principles to consider when performing endodontic surgery.
Principle #1: Determine the periodontal prognosis first.
Periodontal stability should be determined prior to endodontic treatment. Referral to a periodontist should be considered when ≥6 mm probing depths and bone loss to the middle third of the root are present at at least 2 sites. Other site related factors which downgrade prognosis include furcation invasion, mobility, and and deep subgingival restorations. Additionally, poor oral hygiene, sporadic periodontal maintenance, diabetes and especially smoking downgrade the periodontal prognosis.
Principle #2: Detect and manage furcation invasions.
Bone loss in the furcal region is one of the most common factors associated with periodontal abscess formation and eventual molar tooth loss. Bone-sounding utilizing a Nabor’s probe increases the accuracy of furcation detection. If furcation invasion is encountered surgically, the diseased root surface should be debrided with ultrasonic and hand instrumentation since retained calculus in the furcal region may jeopardize healing. Chemical decontamination utilizing a tetracycline or doxycyline slurry is also frequently employed. If attempting furcal regeneration, suitable materials include allografts or bovine xenografts with resorbable collagen membranes.
Principle #3: Respect the zone of supracrestal fiber attachment.
As a general rule, the distance from the apical extent of the restorative material to the alveolar crest should be at least 3 mm. Additionally, the distance from the restorative margin to the cusp tip should be at approximately 9 mm. If these distances are not present, the tooth should be evaluated to determine if crown lengthening is possible. If a restorative material is placed in this zone of soft tissue attachment, chronic inflammation and bone loss will eventually occur.
Princple #4: Know what factors lead to recession in the esthetic zone.
Mid-facial and papillary recession in the esthetic zone can lead to unacceptable esthetic results. Cortical bone in the maxillary anterior region is often very thin or non-existent and full-thickness flap reflection dramatically reduces blood supply to the bone and may lead to soft tissue recession. Also, when planning incisions in the anterior region, it is important remember that the greater the distance from the contact point to the alveolar crest, the more likely a patient is to experience papillary recession if the papilla is transected. Finally, during endodontic surgeries, findings such as vertical root fractures or non-restorable invasive cervical resorption frequently necessitate same-day extractions. While ridge preservation may not be necessary in areas of thick cortical bone, it is nearly always required in the anterior zone to help maintain hard and soft tissue contours.
Principle #5: Navigate the palate carefully.
With the advent of fully-guided apicoectomies, palatal surgery for endodontists will become increasingly common. Some of the major anatomic challenges include: 1. Thick, rigid, bone-bound, keratinized tissue; 2. Palatal tubercles; 3.The greater palatine artery and branches. The greater palatine artery exits the greater palatine foramen apical to the maxillary third molar and lies in a groove at the junction of the alveolar and palatine processes. When hemorrhage occurs, pressure and suction should be applied to allow visualization. For minor, non-pulsatile hemorrhage, various hemostatic agents may be applied such as oxidized cellulose, gelatin matrices, microfibrillar collagen, fibrin sealant and topical thrombin. For severe or prolonged palatal hemorrhage, a compression suture applied posterior to the hemorrhage is often the only effective method for obtaining hemostasis. This can be accomplished with a 4-O chromic gut suture on a large needle. The suture should contact bone to ensure compression of the offending vessel. Blood loss from an arterial palatal hemorrhage can quickly become life-threatening if not addressed.
In conclusion, endodontic surgery is an important treatment option which can help individuals maintain their natural dentition in health, comfort, esthetics and function for many years. Successful surgical therapy occurs when correct biologic principles are understood and applied.
Joseph K. McCombs, D.D.S., M.S., Diplomate, American Board of Periodontology, is a periodontist in Post Falls, Idaho.