Optimal timing for management of impacted canines
In this article, I present a case with blocked maxillary canines emphasizing optimal treatment timing and treatment mechanics utilizing a non-extraction approach and Damon System appliances. The pendulum swing for extraction versus non-extraction treatment has definitely taken a non-extraction direction in recent years. This has placed a new emphasis on arch length development or arch enlargement techniques.
This emphasis appears to have an esthetics-savvy public demanding and appreciating orthodontic treatment plans that are directed at avoiding extractions and potentially creating broader and fuller dental arches.
It is the orthodontist’s challenge to complete diagnostic evaluations for each patient individually and to determine the optimal timing and treatment plan for them. Patients with impacted dentition and late mixed dentition offer a particular challenge when assessing treatment timing relative to growth potential, tooth extractions due to inadequate room for tooth eruption and potential time in treatment.
Self-ligation orthodontic appliances have stimulated discussion and challenged conventional wisdom about orthodontic treatment planning, clinical mechanics, outcomes and stability. Treatment theories are predicated on the appliances and wire interactions providing a more efficient method of force application and resultant orthodontic alignment.
The mechanical interaction of the wire/bracket interface coupled with hard and soft tissue adaptation is stated to “develop” arch width and resultant arch length. It is hypothesized that this combination of arch dimensional and alignment changes promotes the need for fewer extractions with heretofore unseen improved hard- and soft-tissue effects.
In the following case, I will illustrate how these arch enlargement techniques can be successfully managed in a late mixed dentition case. The young female that presented with impacted permanent maxillary canines was treated utilizing Damon brackets with low torque and Damon mechanics to advance incisors and increase transverse dimension, optimizing clinical efficiencies and dental and facial esthetics.
Case study: Diagnosis
A 12½-year-old, healthy female patient presented, following referral by her pediatric dentist, with a concern for crowding and impacted permanent maxillary canines. In acknowledging the significant crowding, the parents and patient vocalized the desire to avoid permanent tooth extractions.
The examination and diagnostic records confirmed facially blocked maxillary canines, lateral incisor malalignment and maxillary first premolars erupting mesially into the canine space. All the maxillary and mandibular primary molars were present, and I noted that there was a significant size difference that would aid in spacing requirements for a non-extraction treatment plan.
In addition, the maxillary incisors were upright and the maxillary midline was shifted to the right, both of which would promote the ability to open canine spacing required. The molar relations were end-to-end.
In developing the treatment plan, I recommended the extraction of the primary molars and to place Damon brackets on the maxillary arch only initially to obtain spacing for maxillary canine eruption.
I have exclusively used the Damon System for more than 14 years and especially appreciate the variable torque options available to assist in managing the mechanics each case demands. In my experience, the Damon System greatly assists with excellent incisor positioning and esthetics. In addition, the passive self-ligating brackets combined with high-technology archwires serve to efficiently develop transverse dimensions without excess crown tipping in most cases.
By addressing the most significant issue of facially impacted canines and opening space for them initially, I was able to avoid the potential for a more difficult impaction management process, hopefully prevent the canines from erupting into poor gingival tissue and prevent the patient from having braces on all the teeth while waiting for teeth to erupt.
I anticipated that the incisor crowns would be moved facially and to the patient’s left. I also predicted the wire progression to develop the facial and transverse arch gain would provide for the space needed without excess proclination of incisors or tipped posterior dentition.
The primary molars were extracted, and to start treatment, I bonded the patient with low-torque Damon brackets on available maxillary teeth and cemented Ormco triple tube bands on the maxillary molars.
This bonding approach allowed for arch tubes to be placed as a “D-gainer” appliance, extending the effective length of the molar tubes to promote wire sliding without falling out of the tubes as open coils opened space for the canines.
The medium level force open coils were activated on round wires initially to correct the midlines and to slide the lateral incisors past the facially positioned canines without torqueing the roots into the canines. Once the lateral roots were moved past the canine crowns, rectangular wires were placed for further arch width development and to begin control of the incisor crown angulation.
To develop dental arch width with the Damon System, it is important to allow the Damon super elastic wires to interact with the passive tube created by closing the bracket slide.
Often the round wires are maintained for up to four to six months for optimal space gain or until all bracket slots are aligned prior to placing rectangular super elastic wires. The 14 x 25 super elastic rectangular wires begin the incisor angulation control early as well as contribute to further transverse development. Following completion of the series of super elastic rectangular wires, final wires of TMA or stainless steel are utilized to complete the alignment, using the arch width developed from the initial wires as the final arch form.
After eight months of maxillary arch only treatment, all the space needed for teeth to erupt was present and the most mal-aligned maxillary right canine had erupted. Progress records were taken to evaluate incisor positioning, and it was determined that the initial goals of opening canine space and optimizing the incisor position without excessive transverse crown tipping or incisor proclination was successful.
The remaining appliances were placed, and while maintaining the arch form in the maxillary arch, the progression of lower arch wires were followed until matched in both arches.
TMA wires were utilized to complete tooth positioning and alignment. We typically use 19 x 25 wires in the maxillary arch and 17 x 25 in the mandibular arch. Using this smaller dimension wire in the lower arch, coupled with “box” configuration elastics of appropriate force levels, promotes improved settling of the occlusion prior to removal of the appliances.
Of course, should the demands of a case relative to lower arch leveling and incisor angulation control require a larger dimension wire in the lower arch, then the clinician should make that determination.
After eight months of initial maxillary arch treatment only, and an additional 18 months of lower arch treatment coordinated to the maxillary arch, the result of 26 total months of care was a result that met all of the patient’s, parents’ and doctor’s expectations.
Treatment time may have been less with the use of lasers to uncover the maxillary canines earlier after obtaining space for their eruption. This would likely have allowed for earlier placement of appliances on the mandibular arch. In addition, there was a two month span from the time it was determined to place the lower appliances and when it was actually completed. Regardless, management of this case resulted in optimized results anticipated by all involved.
In addition, the stability of this case and the healthy periodontal tissues is well demonstrated by reviewing the 24-month retention records. The bonded retainer wires were intact and the patient reported continued periodic wear of removable night-time retainers.
The incisor position within the face was well controlled as space was developed for the facially impacted canines. This was a result of appropriate use of “E” space, transverse arch development characteristic of the Damon System mechanics and advancing the incisors with low-torque brackets, preventing potential for excessive flaring of the incisors.
This case was well managed to reach the goals desired — optimal dental and facial health/esthetics without permanent tooth extractions. In our office, orthodontic care provided with advanced Damon appliances and mechanics has simplified clinical steps necessary to optimize our efficiency while delivering esthetic patient results.
Note: This article was published in Ortho Tribune U.S. Edition, Vol. 9, No. 3, PCSO Edition.