Evaluating and Managing Impacted Lower Canines 🦷

Question:

14F with concerns about her impacted 33/43.  I discussed uncovering the teeth (at OMFS) and moving them into place.  Ext the 73/83.  I discussed possible root resorption, bone loss, recession, and loss of vitality.  I don't want to extract the 33/43 (they are evident bulges under the vestibular gingiva) even tho the 73/83 roots look fine.  What are your thoughts?!  Thanks so much.

Answer:

Impacted Lower Canines

Overview

Impacted lower canines represent a challenging clinical situation due to their anatomical position and proximity to the roots of other anterior teeth. The evaluation of such cases requires careful consideration of several factors, including root resorption, direction of traction, cortical bone involvement, and patient age.

Initial Evaluation

The first step in assessing impacted lower canines is to determine whether any root resorption has already occurred in the lower incisors. The presence of root resorption increases the urgency of intervention. In the case discussed, although one of the radiographic views did not show the absolute apex clearly, there did not appear to be any resorption present at that point—an encouraging sign.

Anatomical Considerations

As the impacted tooth moves, it often needs to pass through portions of the cortical plate, which increases the difficulty of treatment. This is one reason why treating upper impacted canines is generally much easier.

Another factor to assess is the position of the root apex. If the root apex is favorably positioned, tooth movement tends to be more straightforward.

• Lower left canine: The positioning in this case was relatively favorable. The plan was to pull the tooth distally so that it could slot into its proper position.

• Lower right canine: This presented a greater challenge. The crown needed to be moved first, followed by the root. The root apex would require approximately 15 millimeters of tipping to reach the correct position.

Direction of Traction

Traction direction plays a critical role in the success of moving impacted canines. In an occlusal view, the clinician must ensure that traction is applied properly to guide the tooth into alignment without damaging adjacent roots.

For the lower left canine, as long as the movement does not pass through the crowns of the neighboring teeth, the tooth can be safely pulled into position. A button could be bonded to the crown, allowing the tooth to be pulled in an appropriate direction.

For the lower right canine, the required movement is more complex. The traction needs to be applied in a horizontal direction (along the X-axis) before sliding the tooth into place vertically. This horizontal component makes lower canine impactions significantly more difficult than upper ones.

Use of Temporary Anchorage Devices (TADs)

To achieve the correct vector of force, Temporary Anchorage Devices (TADs) can be utilized. A small arm or hook can be attached to the TAD, from which a chain elastic (C-chain) can be connected to the tooth. This setup allows the application of traction in a precise direction to move the tooth horizontally first, passing the root beyond obstacles, before guiding it into its final vertical position.

Clinical Considerations

This type of case can be treated by clinicians experienced with impacted canines and TADs. The speaker noted being comfortable with these procedures, having previously managed numerous cases involving impacted canines.

However, clinical experience is crucial. For practitioners who have not handled at least 50 impacted canine cases, this type of case is not recommended. It is advisable to refer such complex cases to specialists.

Patient Age

The age of the patient in the discussed case was 14, which is advantageous because younger patients typically respond better to orthodontic movement due to ongoing bone remodeling.

Risk of Root Resorption

Radiographic evaluation, such as panoramic and periapical images, should be carefully reviewed for any signs of resorption, particularly on the upper anterior teeth. Evidence of resorption in these regions would increase the risk associated with moving the lower canines over long distances and could influence treatment planning decisions.

Surgical Considerations

In some practices, surgical exposure of impacted canines is performed in-house rather than being referred to an oral surgeon. However, practitioners must be aware of the potential professional dynamics involved.

If a case is referred to a surgeon who disagrees with the treatment plan, there is a risk of the surgeon undermining the general dentist’s credibility with the patient (e.g., questioning why the dentist is managing such a case). This could result in loss of patient trust, even if the dentist is performing the procedure correctly.

Additionally, if attachments such as Kaplan hooks, eyelets, or stainless-steel ligatures detach from the impacted tooth and require surgical re-exposure, the dentist must be confident that the collaborating surgeon will be supportive rather than critical.

Case Selection and Management

For general practitioners, it is advisable to select straightforward impaction cases if surgical collaboration is required. Paradoxically, the more complex cases may be better managed entirely in-house, provided the practitioner has surgical training and experience.

In the discussed practice, all impacted canine exposures are handled internally, as they are considered technically easier than extracting wisdom teeth. Nonetheless, these cases carry inherent real-world challenges that must be carefully weighed.

Conclusion

While managing impacted lower canines can be rewarding, it is a technically demanding procedure requiring precise biomechanics, proper force direction, and interdisciplinary coordination. Given the anatomical, surgical, and interpersonal complexities, the speaker concluded that this particular case should likely be referred to a specialist, as the risks and potential complications outweigh the benefits for less experienced clinicians.