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aa BDS M6 - Oral surgery > Impacted teeth - canines > Flashcards

Impacted teeth - canines Flashcards

1
Q

What is the second most commonly impacted tooth?

A

maxillary canine

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2
Q

What is the prevalence of maxillary canine impaction?

A

1.7%

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3
Q

If a maxillary canine is ectopically impacted, where would this likely be placed?

A

ectopic palatal more than buccal (80% are palatal)

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4
Q

When is the maxillary canine normally palpable in the labial sulcus?

A

10-11 years

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5
Q

Why are canines thought to become impacted?

A

essentially due to lack of space

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6
Q

What are the 2 theories of canine impaction?

A

the guidance theory (Becker et al) - loss of distal aspect of the lateral incisor as the guidance plane for canine eruption

the genetic theory (Peck et al) - result of polygenetic multifactorial inheritance

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7
Q

What are some examples of the aetiology of canine impaction?

A
  • non-resorption of deciduous teeth
  • ankylosis of impacted canine
  • contraction or collapsed maxillary arch
  • absence of lateral incisor to guide eruption
  • presence of pathology, supernumerary, scar tissue in path of eruption
  • trauma causing a disturbance in tooth germ axis
  • cleft lip and palate, syndromes, cleidocranial dysplasia
  • long path of eruption (22mm)
  • displacement of the crypt
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8
Q

What are the clinical investigations for potential canine impaction?

A
  • palpate
  • evidence of rotation/tilting of adjacent teeth
  • mobility/sensibility of adjacent teeth
  • 6 months since contralateral tooth eruption
  • presence of deciduous canine
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9
Q

What are the radiographical investigations for a potentially impacted canine?

A
  • parallax films - PA x2, occlusal and DPT
  • CBCT
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10
Q

What adjacent tooth would more likely be affected by an impacted canine (e.g. rotation/tilting, mobile etc.)?

A

lateral incisor

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11
Q

What does the horizontal parallax technique tell us about impacted canine position?

A

SLOB - same lingual opposite buccal

  • if you move the x-ray cone and the tooth on the radiograph moves in the same direction as the cone, it is lingually/palatally placed
  • if you move the x-ray cone and tooth on the radiograph moves away in the opposite direct, it is buccally/labially placed
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12
Q

What radiographic views are needed to use the vertical parallax technique for localisation of an impacted canine?

A

maxillary occlusal and DPT

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13
Q

What radiographic view is this?

A

lateral occlusal view of canine

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14
Q

What does this radiograph suggest is happening to the impacted canine?

A

follicular space enlargement - evidence of cyst formation

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15
Q

What kind of imaging is this?

A

CBCT of impacted canines

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16
Q

What do these radiographs suggest about the impacted canines?

A

dilacerated roots on canines

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17
Q

How are dilacerated impacted canines managed?

A

cannot be orthodontically aligned - can orthodontically close or create space for an implant, and surgically remove the dilacerated impacted canine

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18
Q

What are the sequelae of leaving impacted canines in place?

A
  • resorption of incisor roots - incidence unknown up to 12.5%
  • cystic change - incidence thought to be low
  • infection of cyst when close to surface mucosa, possible sinus formation
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19
Q

What does this radiograph show?

A

marked resorption of the root of lateral incisor

20
Q

How may this be managed?

A

extraction of lateral incisor and pulling the canine down into the space and masking it as a lateral incisor

or may extract both and place implant

21
Q

What are the 5 treatment options for impacted canines (or any impacted tooth)?

A
  • conservative
  • interceptive
  • exposure
  • surgical removal
  • transplantation
22
Q

When would conservative treatment for an impacted canine be advocated?

A
  • patient unwilling to have orthodontic treatment, or happy with appearance with good contact between the 2 and 4, or healthy C [40yrs], adjacent teeth vital.
  • radiographs show tooth very high, no associated pathology or resorption- usual after 14 years of age

note: Cs will not look good long term due to attrition etc

23
Q

What is interceptive treatment of an impacted canine?

A

extraction of the deciduous canine

24
Q

When would interceptive treatment for an impacted canine be advocated?

A

if patient 10-13 years, minimal crowding, space maintenance.

Note: if no change in position after 12 months on radiographs alternative treatment, 78% erupt normally following treatment

25
Q

When would exposure and alignment of an impacted canine be advocated?

A
  • well motivated patient willing to have orthodontic treatment and good oral hygiene
  • not grossly displaced with favourable root morphology
  • best results if carried out early
26
Q

What are the 2 techniques for exposure and alignment of an impacted canine?

A

Open technique = apically repositioned flap or palatal window

Closed technique = orthodontic bracket and gold chain allowing orthodontic traction (BEST)

27
Q

When is the open technique for impacted canine exposure advocated?

A

when the canine is placed buccally or is in the line of the arch, and is quite superficial

28
Q

Why is the apically repositioned flap/open not favoured over the closed technique?

A

not as good aesthetics - repositioning of the gingiva can result in root exposure when the canine erupts

29
Q

How is a palatally impacted canine exposed?

A

palatal mucoperiostium flap lifted, overlying bone removed, follicle removed

30
Q

In the open technique palatally, what is done to the flap before suturing it back in place?

A

a window is cut in the flap to allow the crown of the canine to be seen

31
Q

What is this?

A

an acrylic plate/a dressing plate used as a barrier to protect the soft tissues after surgical exposure of a palatally impacted canine

32
Q

What is this?

A

co pac soft tissue dressing - a sedative dressing placed on the acrylic plate/dressing plate which helps with post-op discomfort and almost acts as a cushion for the soft tissues

33
Q

How long is an acrylic plate/dressing plate left in place post-operatively?

A

1 week - can still brush teeth that are away form the surgical site and use mouth wash to keep the area clean

34
Q

What does this show?

A

bilateral exposed canines 1 week post-op when the acrylic plate has been removed

35
Q

What technique of canine exposure is being shown here?

A

closed technique

36
Q

What is the benefit of the closed technique using orthodontic brackets when compared to the open/apical repositioned flap technique?

A

mimics the physiological eruption of the canine, meaning it will erupt through attached gingivae giving superior gingival contour

37
Q

Explain what is being shown here

A

closed technique where the gingivae has healed over the bracket placed on the impacted canine and the gold chain has been attached to the orthodontic chain, allowing traction to be applied to the canine to caused eruption through the gingivae

38
Q

When would surgical removal for an impacted canine be advocated?

A
  • patient non-compliant or satisfactory appearance with C or 2-4 contact
  • advanced resorption of incisors (may extract the incisor and incisorise the canine)
  • malpositioned canine with difficult root morphology
39
Q

What is the technique of surgical removal of impacted teeth?

A
  • same flap design as for exposure
  • commonly palatal
  • remover overlying bone to maximum convexity of tooth and elevate
  • sectioning may be required if root morphology complex or position tight against adjacent teeth
  • may need buccal approach to section (even if palatal)
  • plate maybe required post operatively
40
Q

What flap design is used for exposure/removal of palatally impacted canines?

A

envelope flap

41
Q

What flap design is used for exposure/removal of buccally impacted canines?

A

3-sided or 2-sided depending on how much exposure is needed

42
Q

Where do you incise for an envelope flap for exposure/removal of palatally impacted canines?

A

cut round necks of anterior teeth
- from premolar to premolar if bilateral
- from contralateral central incisor to first premolar if unilateral

43
Q

What anatomical feature must be considered when creating a flap for bilateral palatally impacted canines?

A

the nerve bundle which exits through the incisive foramen - can sever this bundle, over time the innervation of the anterior hard palate is taken over by the greater palatine nerve

44
Q

What is the arrow pointing at?

A

the follicular tissue - must all be removed as if left behind could undergo cystic change

45
Q

When would transplantation of an impacted canine be advocated?

A
  • very rarely done anymore
  • poor patient compliance or limited treatment time desirable
  • poorly positioned canine without ankylosis
  • open apex desirable
  • may simply rotate tooth around an axis
  • need adequate space and bone
46
Q

What is the technique for transplantation of impacted canines?

A
  • access as for removal but atraumatic elevation avoiding contact with periodontal ligament/root, tooth ‘parked’ in tissues whilst prepare socket with bur or chisels
  • socket ‘friction-fit’ avoiding heat generation
  • minimal time >10mins
  • may require splint immobilisation
  • check is free of occlusion
  • post op check vitality and resorption
47
Q

What is the failure rate of autotranslation of canines, and for what reasons does this technique fail?

A

failure rate 30% over 9 years often due to poor surgical technique
- internal resorption, perform RCT post op
- external root resorption, particularly if excessive force on tooth in socket
- replacement root resorption, root replaced by bone until exfoliates
- infection

aa BDS M6 - Oral surgery (10 decks)

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