EARLY TREATMENT SYMPOSIUM

Early treatment for impactedmaxillary incisorsAdrian Becker, BDS, LDS, DDOJerusalem, Israel

Atooth normallyerupts when halfto three quarters

of its final root length hasdeveloped. Impaction isusually diagnosed wellafter the tooth shouldhave erupted; therefore,treatment timing is not anissue. Impaction of a per-manent tooth is rarely di-agnosed during themixed dentition period;

furthermore, it is usually corrected in the permanentdentition when general malocclusion is treated. Thenotable exception is the impaction of maxillary centralincisors.

REMOVAL OF THE CAUSE

Many patients with impacted central incisors arefirst seen by pediatric dentists or general practitionerswho then refer them to oral surgeons, believing that, asin most pathologic conditions, removal of the causewill lead to spontaneous resolution. However, studieshave shown that many impacted teeth do not erupt;some need a second surgical exposure, and most willneed orthodontic alignment.

IMPORTANCE OF ORTHODONTIC INTERVENTION

Spontaneous eruption is more likely to occur afterpresurgical orthodontic space opening, removal of asupernumerary tooth, exposure of the impacted tooth,and maintenance of the open area. However, reportsindicate that the impacted tooth can take up to 3 yearsto reach the occlusal level. Furthermore, extensiveremoval of the mucoperiosteal soft tissue and underly-ing bone exacts a price in terms of periodontal prog-

nosis, gingival contour, and appearance of the eruptedtooth.

Rather than waiting for the impacted tooth to eruptunder its own steam, a space-opening orthodonticappliance can be used to augment natural eruptiveforces. A light extrusive force applied to the exposedtooth markedly accelerates its eruption, although statis-tics are not available to define the time differencebetween aided and spontaneous eruption.

It may appear that eliminating the cause of im-pacted incisors would lead to a spontaneous resolution,but this resolution is far from adequate in most cases. Itis therefore necessary to treat impacted maxillary inci-sors with an orthodontic appliance. The logical order oftreatment is as follows:

1. Before surgery, open space for the unerupted tooth,thereby encouraging and enhancing the natural erup-tion process.

2. At surgery, remove any hard or soft tissue obstruc-tion and expose the unerupted tooth.

3. Place an attachment on the tooth, either at surgery orshortly thereafter.

4. Augment the natural eruption process by providingdirectional traction.

5. Align the teeth and relocate the roots of the incisorsin the alveolar bone. Alignment is necessary forteeth that have been displaced buccally, palatally,mesially, or distally by space-occupying supernu-merary teeth, odontomas, or soft-tissue lesions.Alignment and root relocation must be performed atthis stage to prevent future periodontal defects suchas dehiscences, which adversely affect the patient’sprognosis.

PRESURGICAL ORTHODONTIC TREATMENT

For children in the early mixed dentition, a partiallybanded orthodontic appliance should be used, and amodified version of the Johnson twin wire arch isrecommended, although other partially banded appli-ances might function similarly. Space can be createdbetween the adjacent teeth with an open coil springwith sliding mechanics. It is important to extend thespace to include the entire root area, to allow the

Faculty of Dentistry, Department of Orthodontics, Hadassah School of DentalMedicine, Hebrew University, Jerusalem, Israel.Presented at the International Symposium on Early Orthodontic Treatment,February 8-10, 2002; Phoenix, Ariz.Am J Orthod Dentofacial Orthop 2002;121:586-7Copyright © 2002 by the American Association of Orthodontists.0889-5406/2002/$35.00 � 0 8/1/124171doi:10.1067/mod.2002.124171

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unerupted tooth an unobstructed path into the mouth.Therefore, uprighting the roots is mandatory.

SURGICAL APPROACHES

There are 2 approaches to treatment: open eruptionexposure and closed eruption exposure. In eachmethod, any supernumerary teeth or odontomas areremoved, and soft tissue pathology is treated.

Open exposure involves removing the overlyingmucoperiosteum, the alveolar bone, and most of thedental sac surrounding the tooth, thereby exposing itscrown. The wound is left open, and healing is bysecondary intention, through epithelialization over thecut surface. The orthodontist does not have to bepresent at the surgery; an attachment can be placed anytime thereafter because the tooth is in full view.

If clinical access to the tooth is lost in the immedi-ate postsurgical period because the tissue closes overthe wound, a second surgical procedure is necessary.The surgeon must strive to prevent this from occurring,and this often translates to overaggressive removal ofthe dental sac and a reduction in the size of themucoperiosteal flap. Over time, a periodontal price ispaid for this expediency, but it also has an advantage:the orthodontist need not be present at the surgicalprocedure.

To minimize the long-term consequences of thisprocedure, Vanarsdall and Corn1 proposed that the fullsurgical flap should be apically repositioned and su-tured to the labial surface of the newly exposed andunerupted tooth. The long-term results of their studyshowed that this method improved the periodontalcondition after open exposure.

In the closed eruption technique, the surgeon raisesa wide mucoperiosteal flap and identifies the follicle ofthe tooth beneath the surface, usually covered by a thinshell of bone. The surgeon then opens the follicle to theminimum extent necessary to permit hemostasis and tobond a small eyelet or button attachment with astainless steel pigtail ligature. The mucoperiosteal flapis then fully replaced and sutured to totally cover the

surgical field. The surgeon then draws the pigtailligature through the flap at a point that is strategicallyadvantageous for applying directional orthodontic trac-tion.

POSTSURGICAL ORTHODONTIC TREATMENT

The pigtail ligature is shortened and fashioned intoa small hook, as close as possible to the gingival tissue,and the orthodontic appliance applies light extrusiveforce. The impacted tooth erupts through the healedtissue in a manner resembling normal eruption. Once itis fully erupted, suitable tipping, rotational, uprighting,and torquing forces are applied to the tooth to achieveadequate alignment.

EVIDENCE BASE

In a recently completed study,2 a standardizedorthodontic protocol was used to treat 21 patients withunilateral impacted central incisors. For each patient,the surgeon used the closed eruption method, placed anattachment on the impacted tooth at surgery, and fullyclosed the flap. Traction was applied immediately. Thepatients were seen at least a year after treatmentcompletion and were evaluated for periodontal andpulpal status and tooth appearance. The researchersused a split-mouth design to compare the treated andthe unaffected sides of the patients’ mouths. Theappearance of the treated teeth was excellent. The mostcommon findings were mild gingival irregularity andcrown opacity caused by pulp obliteration, loss ofattachment, and relative bone loss. However, thesepulpal, periodontal, and esthetic shortcomings wereclinically insignificant and did not adversely affect theperiodontal prognosis of the treated teeth.

REFERENCES

1. Vanarsdall RL, Corn H. Soft-tissue management of labiallypositioned unerupted teeth. Am J Orthod 1977;72:53-64.

2. Becker A, Brin I, Ben-Bassat Y, Zilberman Y, Chaushu S.Periodontal status following surgical-orthodontic alignment ofimpacted maxillary incisors by a closed-eruption technique. AmJ Orthod Dentofacial Orthop 2002; in press.

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