Pericoronal ostectomy as alternative treatment option for extraction of impacted mandibular third molars in proximity to inferior alveolar nerve
An extraction of third molars is one of the most common surgical procedures performed by oral and maxillofacial surgeons in private practice. In cases of a close relationship between the impacted mandibular third molar and the mandibular or inferioralveolar canal, alternatives to tooth extraction include observation with or without an antibiotic regimen, operculectomy with removal of the inflamed pericoronal gingival tissue (rarely done), coronectomy (partial odontectomy), or the recently described orthodontically aided eruption of mandibular third molars (orthodontic extraction).
It has been shown that coronectomy reduces the incidence ofinjury to the inferior alveolar nerve (IAN), and the infection rate of the remaining roots has been low. The side effects of coronectomy include formation of deep periodontal pockets behind the second molar, the possibility of endodontic infection related to the exposed pulpal chamber of the remaining roots, dry socket, and others.
A recently published orthodontic extraction approach has alsoshown promising results with orthodontically aided “forced” eruption of an impacted third molar away from the danger zone of the canal. It also appeared to promote periodontal healing behind the second molar. The drawbacks of this technique include the need for placement of an orthodontic appliance (lingual and bucal wires), frequent buccal soft tissue trauma from the appliance, the possibility offailure owing to tooth ankylosis, and the prolonged treatment time (range, 6 to 12 months).
We have recently introduced another alternative surgical technique for mandibular third molars in dangerous proximity to the IAN in our practice. We have called it pericoronal ostectomy. In essence, this procedure involves the removal of bone around the crown (thus, “pericoronal”) of a partially or fullyimpacted (usually mesioangular) mandibular third molar in an attempt to eliminate any obstruction and promote the potential future eruption of the tooth occlusally and away from the IAN.
During this procedure, a hockey stick-shaped, buccal full-thickness flap is reflected in a standard fashion. Next, the bone around the crown of the partially or fully impacted mandibular third molar is completelyremoved. If the lingual bone is positioned occlusally, it should also be removed. This should be done with careful reflection of the lingual flap and placement of a protective instrument, such as a Seldin or No.9 Molt periosteal elevator. The impacted tooth is dislocated slightly (subluxated), and the flap is repositioned back without suturing.
This surgical approach is based on the presence of anobstruction of the path of third molar eruption (between the second molar and the ascending ramus) by the overlying bone (pericoronal bone). The removal of bone all the way around the crown (pericoronal ostectomy) and luxation of the tooth to boost its eruptive potential (similar to surgical orthodontics with exposure of the unerupted canine, premolar, and so forth) often leads to a slow eruptionof the mandibular third molar upward and away from the IAN.
Usually, within 2 to 6 months, in our experience, a more occlusally positioned third molar can be safely removed with a decreased possibility of nerve injury.
This surgical approach is especially favorable in cases of incomplete root formation in younger patients 14 to 18 years old. In these cases, the potential for the roots to continueforming and for an impacted third molar to continue its eruption path away from the IAN in a “unobstructed environment” is greater.
The case demonstrating the proposed technique is illustrated in figures 1 to 3. A 27-year-old patient presented to our oral surgical practice with a recent history of severe pain behind the lower second molar and an inability to chew. The clinical and panoramic...
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