CC
A 14-year-old male is referred to your office by his orthodontist for exposure and bracketing of an impacted left maxillary canine (the canines normally erupt between 11 and 12 years of age). The maxillary canines are the second most commonly impacted teeth (the most common are the third molars).
HPI
The patient has a history of premature loss of the primary left maxillary canine secondary to trauma. (Premature loss of teeth with subsequent arch length reduction is one of the many causes of impaction.) Orthodontic treatment has begun, and sufficient arch space has been accommodated for the guided eruption of the impacted canine. The patient has no history of any other impacted or congenitally missing teeth and presents with an otherwise full dentition.
PMHX/PDHX/medications/allergies/SH/FH
Noncontributory.
Examination
General. The patient is a well-developed and well-nourished male in no apparent distress.
Maxillofacial. He has a symmetrical facial appearance with no obvious skeletal abnormalities.
Intraoral. Orthodontic bands, brackets, and arch wires are in place. A well-healed edentulous space is present in the area of the left maxillary cuspid with an adequate alveolar ridge. A small, painless, palpable bony buccal protuberance can be noted in the area of the left maxillary cuspid, consistent with the crown of the impacted canine. (Clinical evaluation to determine palatal or buccal impaction is important and often sufficient to determine the approach for access to the tooth.) The gingival and palatal tissues both appear healthy, with no notable periodontal defects.
Imaging
A panoramic radiograph is the initial screening study of choice for evaluating impacted teeth. It provides an excellent overview of the dentition, associated dentoalveolar structures, and location of impacted teeth. Periapical “shift shots” can help determine whether the tooth is buccal/labial or palatal/lingual. (The SLOB rule [ s ame l ingual, o pposite b uccal] is frequently used to determine the position of the tooth on the subsequent x-ray film as the cone of the x-ray machine is moved anteriorly or posteriorly.) Occlusal films, lateral cephalometric films, or computed tomography (CT) scans can be used for precisely locating the position and orientation of impacted teeth.
In-office, small-field cone-beam computed tomography (CBCT) provides the most convenient and valuable imaging method; it demonstrates not only the canine position but also the details of angulation, orientation, and relationship to adjacent structures (see the figures in the section on CBCT in Chapter 1 ). This information can be beneficial for the surgeon’s treatment plan and the choice of surgical approach in addition to aiding the orthodontist in determining the path of eruption. CBCT may also detect root resorption of adjacent teeth that is not evident on panoramic radiographs. Haney reported significant changes in position diagnosis, root resorption detection, orthodontic vector determination, and surgical access planning by a group of orthodontists and oral surgeons who reviewed CBCT images compared with review of traditional radiographs of the same patients.
In the current patient, the panoramic radiograph shows a fully formed impacted left maxillary cuspid with a mesioangular orientation. Fig. 28.1 demonstrates the position of the impacted canine before the initiation of orthodontic therapy. The crown of the canine appears to have a pericoronal radiolucent lesion consistent with a hyperplastic dental follicle (although a dentigerous cyst or other pathologic processes are also possible). No crestal bone loss is noted in the surrounding region. The full bony impacted third molars are also noted.
Labs
No laboratory studies are indicated for routine exposure and orthodontic bracket placement of impacted teeth unless dictated by the medical history.
Assessment
Full bony mesioangular labially impacted left maxillary canine.
Treatment
Current popular treatments of impacted canines can be divided into open and closed surgical techniques, differing slightly in regard to palatal versus labial impactions. Autotransplantation and extraction with implant replacement are less commonly used techniques and are described later with other historical techniques. Extraction of the primary canine may be considered if the patient is between 10 and 13 years old and sufficient arch space has been created, allowing observation for normal eruption of the permanent canine. Serial radiographs can be used to monitor eruption, and if no movement is observed over 12 months, alternative techniques should be performed.
Open techniques. These surgical techniques are indicated when the crown of the impacted canine is in an appropriate location near the alveolar process, allowing exposure and access for orthodontic bracket placement. For palatal impactions, the excision of overlying soft tissue may be performed with a surgical blade or electrocautery as a “window.” Care should be taken to preserve sufficient soft tissue between the “window” and the cervical margin of surrounding erupted teeth to avoid potential tissue necrosis and periodontal complications. Bone removal may be performed with a rotary instrument, rongeurs, or hand instruments to expose the crown to the level of the cervical margin. Complete exposure of the crown may not be feasible in cases in which the crown is in close proximity to incisor roots. Any dental follicle remnants should be excised at this time. Gentle luxation of the tooth may be performed to rule out ankyloses, but luxation of the tooth is controversial, with some studies suggesting this luxation may actually lead to ankylosis or root resorption. An orthodontic bracket with gold chain may be etched and bonded to the crown with the chain attached passively to existing orthodontic arch wires. The wound may be left open or packed with a periodontal dressing for a period of 4 to 5 days. It is generally accepted that a period of 6 to 8 weeks is observed for both palatal and labial impactions to allow for spontaneous eruption before the application of orthodontic forces. The apically repositioned flap is the open technique of choice for labially impacted canines. Electrocautery, or a “window” excision of overlying soft tissue, should be avoided with labial impactions because it usually results in a lack of attached gingiva after eruption, with a possible need for a secondary graft procedure. A full-thickness mucoperiosteal flap with vertical releasing incisions is raised to the level of the vestibular sulcus followed by bone removal, follicle removal, and crown exposure and luxation as previously described. The distal aspect of the flap is positioned apically and sutured with chromic gut at the level of the cervical margin, thus placing attached gingiva at the level of the cementoenamel junction. Again, the bracket with chain may be bonded at this time.
Closed Techniques. These surgical techniques are indicated when the crown is not near the alveolar process or is in a position that inhibits the apical repositioning of a flap ( Figs. 28.2 and 28.3 ). In both palatal and labial impactions, a full-thickness mucoperiosteal flap is raised, allowing subsequent crown exposure, gentle luxation, and bonding of the orthodontic bracket with a chain. At this point, the chain may be brought through the distal aspect of the flap (or through a stab incision in the body of the flap), and the full flap is repositioned and sutured. In closed techniques, orthodontic forces may be applied after 1 week to allow for soft tissue healing.
