F(Ortho) - Impacted canine notes

How do you examine canine impaction ?​

• Inspection ​

• Palpation​

• Radiographic Examination

  Inspection

  • Distally tipped or buccally tipped lateral​

  • Absence or presence of labial bulge

  • Presence of a palatal bulge

  Palpation

  • The canine is Palpated at the buccal mucosa at the age of 10 ​

  • Absence of buccal bulge might indicate a palatally impacted canine

Radiographic assesement

• OPG​ can give us an idea of the position of the canine

• we can also use Parallax method to get more accurate results

• lastly we can use CBCT if conventional radiographs werent diagnostic or if we suspect root resorption

What clinical feature that you see , that might neccisitate radiographic assesement ?

• Ericson and kurol outline three clinical features that indicate a radiographic examination to determine the position of the unerupted permenant canine is necessary:​​

  • Asymmetry on palpation​

  • The canines cannot be palpated in the normal positions, and the occlusaldevelopment is advanced​

  • The lateral incisor is late in eruption or shows a pronounced buccal displacement

What is the incidence of impacted canine ?

• 2% (Ericson and kurol)

Does it appear in females or males more ?

Females

• Female: Male 2:1

Whats the incidence of Palatally impacted canines ?

61%

• Palatal: Line of the arch : Buccal - 61% : 34% : 4.5% (Stivaross and Mandal)

You mentioned that you can use the OPG to assess the position of the canine, how can we do that ?

• it depends on the fact that objects nearer to the X-ray source and further from the film appear larger than objects close to the film. (Chausho and becker)

Whats the Prognosis of this impacted canine ?​​

• Determining the prognosis of canine from OPG

• Proximity to midline​

• Angulation​

• The vertical position of canine​

• Position of the apex of the canine root​

• Age of the patient (Maturity of canine root)

Whats a more accurate method ?

Parallax technique

• Horizontal parallax​

• Vertical Parallaax​

How can you do the Horizontal Parallax technique ?

Horizontal Parallax

• 2 periapicals​

• or Anterior occlusal + periapical

What about the Vertical Parallax ?

Vertical Parallax

• OPG+ Anterior occlusal​

• or OPG+ Periapical

Which is more Accurate ?

According to Armstrong (2003) Horizontal parallax is more accurate than vertical

Do you think taking a CBCT here was justified ?

• Your answer will depend on ,

• The proximity of the canine to adjascent teeth

• Was a less invasive method used first like the Parallax technique

• Were there any symptoms or displacements in the lateral incisor ? (or the tooth in close proximity yo the canine )

If these points check in the case then you can say that it is justified as per the points we previously mentioned , if not all of them check Like fore example Point 1 and 3 checked but the parallax technique wasnt done you can say that even thought the canine shows close proximity i wouldve preferred that he used a less invasive method first

Whats the problem with OPG in assessing impacted canines ?

• The problem with OPG is that it overestimates angulation and underestimates proximity to the midline this view should be supplemented with an intraoral view

What could be the possible cause the impacted canine ?

• Answer according to the case you have , usually the cause is multifactorial , for example if the patient is a female and she has crowding

• you could say that the cause is multifactorial it could be due to genetic inheritance , the higher incidence of impacted canines in females than males and due to the crowding the patient has the canine wasnt able to find space to erupt

When would you let the canine be and do not anything about it ?

• Patient not willing to go for the treatment

• Poor prognosis of canine

• There should be no evidence of root resorption of adjacent teeth or other pathology.

• Ideally, there should be good contact between the lateral incisor and first premolar, or the primary canine should have a good prognosis.

• Such patients should be reviewed bianually and warned from cystic changes that might happen(. No guidance currently exists as to how frequently radiographic checks should be done)

Open Eruption Superficial

Should have attached gingiva atleast 2mm (if buccal impaction)

Benefits:

Short surgery time

easy visualization

not sensitive technique

Disadvantages:

Pain and discomfort

More liable to infection

Closed eruption

Deep impaction i.e covered with bone

Benefits:

Immitates normal eruption

Decreased patient discomfort

Disadvantages:

Less predictable

Might need another surgery if gold chain debonds

Apically Repositioned flap

Insufficient amount of attached gingiva

canine overlap root of lateral

Contraindicated in very high canines

When would you consider translpantation of the canine ?

• Transplantation is not normally considered unless other possible active (or interceptive) treatment has failed or is considered to be inappropriate.

• This treatment option can be considered if the patient is unwilling to wear orthodontic appliances, or the degree of malposition is too great for orthodontic alignment to be practical.

• .The best results are achieved if the ectopic canine can be removed with minimal trauma and before closure of the apex. (RCSENG Guidelines)

Reference

• Management of devoloping dentition (Cobourne)

• Management of the Palatally Ectopic Maxillary Canine 2022 RCSENG

• How to…mechanically erupt a palatal canine (Padhraig S. Fleming ,Pratik K. Sharma , UK Andrew T. DiBiase)

Causes of canine impaction ?

• Polygenetic inheritance

• Guidance theory (Becker)

• Long path of eruption

• Retained C

• Ectopic path of eruption

• Crowding

CBCT

• A recent dosage review of dental imaging between​

  2010 and 2020 has shown an average effective dose​

  from CBCT, (delivering the greatest dose compared​

  with intraoral and panoramic radiographs), more​

  than 92 times greater than intraoral and 7 times​

  greater than panoramic radiography.

• Usually done when conventional radiographs haven’t been diagnostic​ or when root resorption is expected​

• root resorption of lateral incisor incidence :

• 12% of cases showed resorption of lateral incisors with plain radiographs (ericson and kurol)

• CT studies show 48% of lateral incisors demonstrate a degree of root resorption

• CBCT showed 66% resorption of 2’s and 11% of 1‘s (Walker)​

Canine Treatment planning Questions:

Why would'nt you extract the Canine itself ?

Usually we do not extract the canine due to its aesthic , restoractive and functional importance , and 2-4 contact is not ideal to occlusal interference (Thiruvenkatachari)

When would you Choose to extract the canine ?

• The surgical removal option should be considered if the patient declines active treatment and/or is happy with their dental appearance.

• Surgical removal of the ectopic canine should be considered if there is radiographic evidence of early root resorption of the adjacent incisor teeth (but exposure and alignment of the ectopic canine is usually indicated in cases where severe root resorption of an incisor tooth has occurred necessitating the extraction of the incisor).

• The best results are achieved if there is good contact between the lateral incisor and first premolar, or the patient is willing to undergo orthodontic treatment to substitute the first premolar for the canine (RCSENG Guidelines)

• If canine is in good contact with the 4

• if a is in an ectopic position which is unfavourable for alignment

• Cystic changes

  (Thiruvenkatachari)

What Changes would you make if you chose to Extract the canine ?

Since the 4 is going to be my new canine im going to place the bracket of the canine on the 4 to produce a negative torque and produce the same tip as the canine iim going to place the bracket more incisal to raise the gingival margin and more distally to rotate the tooth mesiopalatally and so hiding the palatal cusp of the 4 , and i would gradually do selective grinding to the palatal cusp to further hide it.

Whats the torque of the 4 in the MBT prescription ?

• -7 degree

Why not leave the Bracket of the 4 ?

Because the Tip of the 4 bracket is different , the 4 tip is 0 while the 3 tip is 8 degrees

lets say you chose to keep the canine ,Which type of exposure would you do to the canine ? open or closed expoure ?

Whichever answer your going to choose according to the case, justify it with the benefits mentioned and mention the disadvantages of the other options as justification

First of all you will mention that there is no difference between the 2 according to Parkin et al, but in this case im going to choose to do ........... due to ...... (mention your justification)

Here is a comparison of all 3 methods , and when to choose each and the advantages and disadvantages to justify your answer

Determining the prognosis of the canine .

Who made this criteria of assessing the prognosis ?

Mcsherry and Pit

What mechanics Would you use here to Disimpact the canine ?

Say the mechanics that you are most familiar with and the most suitable with the case

Methods of erupting an impacted canine :

• Trans-palatal arch (TPA) with stainless steel auxiliary

• TMA ‘fishing-rod’

• Magnets

• Temporary anchorage devices (TADs)

• Elastomeric traction to fixed appliance

• Piggyback NiTi archwires

• Stainless steel archwire auxiliary

• Nickel–titanium and other customized auxiliaries

Check out Fleming et al Paper "How to…mechanically erupt a palatal canine"