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Impacted and ectopic canines

Impacted and ectopic canines

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Why a section solely on impacted canines?

– Because canines have a specific and unique role in the mouth and dentition and they are often affected by severe eruption problems.

– Because their behavior is hard to predict; they behave sometimes like a “jack-in-the-box”; we never know when and how they will come out!

– Here are some facts about canines:

  • Function: Canines have a particular functional role; they guide the mandible when it moves, which protects the other teeth by preventing them from being in contact with each other. If they are malpositioned in the dental arches, other teeth will have to play the role of the canines and this may cause short or long-term problems (wear, jaw joints problems, etc.).
  • The canine is one of the most solid tooth in the mouth and it can bear significant forces. Its root is one of the longest among all the teeth, including molars.

NORMAL OCCLUSION: when they are in function, the canines are the only teeth to touch when the mandible moves (A and C) to the right and (B and D) to the left. No other teeth, anterior or posterior, must ideally touch during side movements (C and D = front view).


Upper impacted canines: a few facts

Possible consequences of an impacted canine

Appearances are sometimes deceptive


Palatally impacted canines and dental resorption, malocclusion

(A, B and E) X-rays showing the severely impacted permanent upper canines (red *) and wear of the root of several teeth (arrows). The temporary canines are still in the mouth at 27 years of age, which is abnormal.


Prevention and interception

Palatally impacted upper canines (indicated by the arrows)

Palatally impacted upper canines (indicated by the arrows). The temporary canines are still in the mouth.


X-ray and picture showing the position of the canines in the palate (indicated by the arrows)

Radiograph and picture showing the position of the canines in the palate (indicated by the arrows).


Palatally impacted canines in an adult

Complete resorption of the roots of the lateral incisors by impacted canines at 12 years of age

Severe resorption of lateral incisors by impacted canines at 12 years of age

(A) This malocclusion, that seems harmless and looks like many others, however hides a serious problem in a 12-year-old young girl; the impacted upper canines have completely worn out the roots of the permanent lateral incisors in such a way that these teeth cannot be saved and will have to be extracted. (B) X-rays show the extent of the resorption of the roots of the lateral incisors (red arrows). The crowns of the lateral incisors are indicated by blue asterisks (*) whereas the permanent canines, having caused the resorption, are indicated by a red asterisk. At 12 years of age, the lateral incisors have erupted since barely 4 years and they are already sentenced to extraction.

Etiology (causes)

  • Upper canines normally erupt toward the dental age of 11 years old, but it is indicated to investigate their position and eruption path by with radiographs one to two years earlier.
  • Incidence: there is a clear family trend (heredity); if a family member has an impacted canine, 40 % of the members of his/her family had some as well (Todd, 2008).
  • Guidance: the upper canine needs the lateral incisor during its normal eruption process. It uses the root of this tooth as a “guide” to make its way to its final destination in the arch.
  • If the lateral incisor is absent, misshapen, badly positioned, or is abnormally affected by resorption (root), it can affect the eruption of the canines and cause an ectopic eruption.
  • If the primary canine does not resorb normally, it will cause a mechanical obstruction that may affect or prevent the eruption of the permanent canine.
  • During normal eruption, canines go down following the roots of the lateral incisors and will bring the incisors closer together by moving them mesially. Thus, they can close a diastema (space) between the central incisors (see illustration on the opposite side).
  • Most of the time, an ectopic canine (this also applies to other teeth) is a sign of a significant lack of space in the affected dental arch.
Resorption of temporary roots; a normal phenomenon

  • During the eruption process, the permanent canines must resorb (wear down) the roots of their temporary predecessors.
  • Palatally impacted canines do not resorb the roots of the temporary canines, so these teeth can stay in place and be “solid” for a very long time, until adulthood.
  • When the patient described above (21-year-old young woman) started her orthodontic treatment, the temporary canines were extracted. Their root only showed very little resorption (indicated by arrows on the picture).
  • When a developing canine is significantly malpositioned, it can cause the same kind of damage to the permanent lateral incisors, which is not desirable, unlike the temporary canines, and may compromise the survival of the affected teeth.
Root resorption by an impacted canine. Extraction before an orthodontic treatment.

The “iceberg syndrome” !

  • We use this expression to describe the phenomenon where people only see one aspect (esthetics) of the problem, that is only one misaligned tooth (canine) that they find unesthetic.
  • In reality, the (invisible) cause is much more important, like the iceberg that only shows one peak at the surface of the water, while hiding an enormous mass underneath the surface. People would like it very much to align “only one crooked tooth”, but very often, this is impossible because the problem in its entirety must be considered.
  • An ectopic canine often indicates an underlying space problem that is much more important than what can be seen at first sight.

A panoramic X-ray allows the evaluation in more depth what is not always visible in the mouth

The panoramic radiograph allows the evaluation of what is not always visible in the mouth. The upper canines are much tilted forward and do not have enough space.

Loss of space and eruption problems visible on a X-ray of an 11-year-old young boy

Loss of space and eruption problems in an 11-year-old boy. The upper and lower canines are already completely blocked by the premolars that try to come out.

Ectopic cuspids orthodontics

Examples of ectopic canines. One or several canines may be affected. They can erupt outward or inward on the palate side.

➡ To see other examples of ectopic canines.

Treatment of impacted canines

The treatment of impacted canines necessitates the creation of space in the dental arch (extraction, orthodontic displacement of other teeth), to expose the impacted tooth in order to bond an attachment to it and apply an orthodontic traction using a light force to make the tooth “come down” into place and position it in the dental arch. The following diagrams illustrate these different steps.

Orthodontic traction of an impacted canine. (A) The temporary canine that is still in the mouth must be extracted (*). (B) The palatally impacted canine (in red) must be pulled out and a traction attachment is bonded to the tooth. A little chain or ligature links the attachment to the orthodontic wire. (C) An elastic band pulls the little chain to guide the canine toward the dental arch. (D) When the canine has come down enough, the little chain and the attachment can be removed. (E) A regular bracket can now be placed on the tooth to end the correction. (F) Final result with the canine normally positioned in the dental arch (ill.: AAO 1993)


Impacted canines and orthodontic traction

Palatally impacted upper canines in a 13-year-old girl. Extraction of temporary canines and orthodontic traction. See legend below for details.


Anterior esthetics during traction of an impacted canine

A question that is frequently asked is about how visible the attachments and traction ligatures are during the treatment. They are just barely visible.

Traction of an impacted canine in orthodontics

(A) It is possible to appreciate, with the X-ray, the length of the traction ligature buried in the mucous membrane of the palate. (B) A small part of the little chain comes out of the gum to attach to the archwire. (C and D) Artificial teeth fixed on the brackets bonded to the wire hide the space where the canines will be, as well as the little chain.


Impacted canine incluse and orthodontic traction

(A) At the beginning of traction, the loops of the little chain are visible outside the gum. (B and C) Once the canine has almost reached the surface, the little chain is cut and a wire or another traction mode may be engaged directly in the attachment bonded to the surface of the canine. (D and E) Despite the fact that the little chain is quite long (visible on an X-ray), what appears in the mouth is very negligible and practically invisible.


Is traction of an impacted canine “guaranteed”?

  • NO. As for any dental or orthodontic procedure, the orthodontist cannot promise or “guarantee” any result during the traction of an impacted or ectopic canine. He can only ensure that all means are taken and all proven and known techniques are used to reach the treatment objectives  that he defined with the patient and/or his/her parents.
  • An impacted canine is a particular challenge in orthodontics and several factors will influence the success of treatment, such as the severity of the impaction, the patient’s age, his/her cooperation during the treatment, etc.
Results in orthodontics are not guaranteed.

Importance of adequate supervision during the eruption of teeth

The following examples (cases 1 to 3) show similar conditions and possible long-term consequences of an impacted canine.

Case 1: This 15-year-old young girl would have a very acceptable occlusion if her upper right canine was not palatally impacted.

(A) The occlusion is generally excellent, but we notice the presence of a temporary upper right canine (*). (B) The X-ray reveals the presence of the impacted canine which is very badly positioned (red arrow). This problem could have been avoided or minimized. The blue arrow indicates the canine on the opposite side that erupted normally.


Could this situation and the following ones have been avoided? To know more on prediction and interception of impacted canines.



Case 2: This other example could demonstrate what could have happen to the previous case if it had been left without supervision for several years.


26-year-old woman with a good occlusion except for an impacted canine that caused damages to the bone and to an adjacent tooth. See explanations below.

Case 3: The longer the situation lingers, the more chances wear will occur!

Palatally impacted canine, tooth wear and malocclusion

(A) Palatally impacted upper right canine. (B) Radiograph showing the impacted canine. (C) Function of the jaw on the right side; wear of the lateral incisors. (D) Excessive overbite.

Case 4: Early detection and intervention

  • Using an X-ray, a perceptive dentist wanted to verify why the upper lateral incisors were tilted.
  • We discover the presence of a pathology (cyst) around the crowns of the impacted canines (arrows). These cysts cause bone destruction (dark zone) that may affect the lateral incisors.
  • It is indicated to extract temporary teeth (selective extractions) in an attempt to redirect the canines and eliminate the pathology. Such an intervention minimizes the chances of seeing the canines become palatally impacted later.

Pathology (cyst) around impacted upper canines

Cyst and bone destruction around the crowns of the impacted upper canines.


Case 5: Serial extractions and guidance of eruption
One of the best ways to influence the eruption of permanent canines that do not find their way normally is to perform serial extractions. This consists of selectively extracting temporary teeth to make space for the replacement permanent teeth that try to erupt and come out. The example on the right how the extraction of two temporary teeth (*) allowed a canine (dotted red line) to straighten up and head toward where it must erupt in the dental arch. Even if this intervention improves the eruption of the canine, a lot of space is still missing to allow the normal eruption of this tooth and orthodontic corrections will still be necessary later to regularize the situation and obtain a normal occlusion.To know more on serial extractions.

Selective extraction and eruption guidance to help the eruption of a canine.

(A) Canine tilted toward the lateral incisor (dotted line). The temporary teeth (*) will be extracted. (B) A little more than one year after the extractions, the eruption path of the permanent canine significantly improved.

Functional canines minimize tooth wear and damage

Example of "functional" wear in a 14-year-old girl;  (A) The upper canines are high and cannot play their protective role during normal jaw movements. (B) When the mandible moves to the right (above pictures) or to the left, the lateral teeth touch and start to wear out. (C) At the end of the movement, wear is visible on the tip of the lateral incisors which have already shortened.

Example of “functional” wear in a 14-year-old girl; (A) The upper canines are high and cannot play their protective role during jaw movements. (B) When the mandible moves to the right (above pictures) or to the left, the lateral teeth touch and start to wear down. (C) At the end of the movement, wear is visible on the tip of the lateral incisors which have already shortened.


Canine function and tooth wear

This 24-year-old young man shows a situation where we can compare the functional role of the canine on both opposite sides. (A) The upper right canine (blue arrow) touches the opposite canine and is in function during the mandibular movements to the right. It already starts to show signs of wear; the tip is flat. On the opposite side, the canine does not have enough space and is outside the arch (yellow arrow) and consequently, is not functional, does not show any signs of wear and the tip is still very pointy just like when this tooth erupted. (B) When he opens his mouth, we can better appreciate  the difference between the tip of both canines and notice that the right canines already show significant wear for a young adult (circle). The left canines being less functional, the incisors must therefore  guide the jaw and this contributes to wearing down their incisal edges.


Up to what age can an impacted canine be treated?

Impacted canine treated in orthodontics in an adult. Orthodontist Lemay Sherbrooke orthodontics by Lemay orthodontists

(A, C, D) The upper left canine of this 46-year-old man is palatally impacted. The temporary canine is still in place (arrow and blue *). (B, E, F) The orthodontic treatment allowed the permanent canine to be put into place (arrow and red *). It shows a darker color because it has never undergone whitening or another surface treatment like the other teeth which have been in the mouth for more than 30 years.

Extractions do not correct anything!

Extraction of a tooth to correct a malocclusion.

(A and B) This 19-year-old young woman had one of her lower left premolars extracted (where indicated by the blue arrows) to help the eruption of the canine. Even though this facilitated the eruption of the canine, the effect was disastrous on the alignment of teeth that shifted to the left (red arrows), causing a significant asymmetry of the midlines (blue lines = middle of each dental arch). (C) A line going through both lower canines shows the significant asymmetry that developed following the migration of teeth in the space created by the extraction of the premolar.

When such an extraction is envisioned, it is still indicated to preserve the space using orthodontic appliances to guide the eruption of the teeth and prevent undesirable dental movements that will cause other problems.

Other examples where a malocclusion remains and even got worse following extractions that were supposedly performed to “help” or improve these malocclusions.

Extraction of 3 premolars (indicated by the arrows), deviation of the midlines and uncontrolled migration of teeth. There is as much dental crowding and occlusal problems despite the extraction of 3 teeth that “was made to fix the problem”. The upper left canine (*) is still as crooked and has not enough space despite these extractions!


Dental extraction and severe malocclusion

Severe malocclusion (anterior and posterior open bite, maxillary constriction, dental crowding, asymmetry). An upper left premolar was extracted at an early age (blue arrows), the upper teeth shifted to this side, worsening the asymmetry of the midline (A and B-yellow arrows and red line), without improving the severity of the malocclusion, esthetics or function at all. This case still requires a major orthodontic intervention, but on top of that, the orthodontist must deal with a more severe asymmetry.


Extraction contributing to a dental malocclusion

Extraction of an upper right premolar (arrow) having created a significant asymmetry in the maxillary arch.


Facial asymmetry and dental extractions, malocclusion

Significant asymmetry caused by the extraction of premolars without subsequent supervision. (A and B) The extraction of an upper and lower premolars on the right side (arrow) caused the movement of anterior teeth to the right. The dotted line shows how significant the shift is. (C) The mandible and the chin also shifted to the right. The yellow line is aligned with the upper central incisors shifted to the right. (D) The deviation of teeth affects the smile esthetics. (E) The arrows indicate where the teeth were extracted.


➡ To know more on midlines and asymmetries of the dental arches. Dental midline.

The protective role of the canines

No canines = no guide = tooth wear

Tooth wear and impacted canines orthodontics

Tooth wear of incisors caused by the absence of canines to guide the mandible when it is in function.

Importance of canines in the normal closing of a diastema

Canines follow the roots of the lateral incisors in their eruption path and can close the space between the central incisors. It is preferable to wait for the canines to come out before envisioning a labial frenectomy when a diastema is present. (Broadbent 1937)

Eruption of canines that contribute to the closing of a diastema.

Example of a normal diastema closure between the upper central incisors following the eruption of permanent canines. (A) At 8.9 years of age, this boy shows a significant diastema and a labial frenum that attaches between the central incisors. (B) Almost 5 years later (13.5 years of age), the permanent canines have erupted and contributed to closing the diastema by moving the incisors mesially. No frenectomy was performed.


Extraction of canines? In rare cases only

This section is under construction, but you will find more information about it in an answer to a question in French.






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