5- Impacted Cuspids (Dr. Salam)

True

T/F: Teeth tend to erupt in the same sequence in which they calcify

6124537

(1M, Ci, Li, 1PM, 2PM, C, 2M)

What is the most common (favorable) eruption pattern in the maxillary arch?

6124753

(1M, Ci, Li, 1PM, 2M, 2PM, C)

(2nd molar before the canine is bad; when we see 2nd molars erupting before the 2nd premolar it encroaches on the space of the 2nd premolar)

What is the MOST UNFAVORABLE pattern of eruption for the maxillary arch because it leaves no space for the canine??

True

T/F: Teeth generally erupt in pairs

0.92-2.2%

What is the prevalence of canine impaction in the population?

Females

Is canine impaction 2x more common in males or females?

8%

__% of all impacted canines are bilateral impactions

labially or within the alveolus

About 1/3 of impacted maxillary canines are positioned ________

palatally

About 2/3 of impacted maxillary canines are positioned ______

1. Tooth size-arch length discrepancies

2. Failure of the primary canine root to resorb

3. Prolonged retention or early loss of the primary canine

4. Ankylosis of the permanent canine

5. Cyst or neoplasm

6. Dilaceration of the root

7. Absence of the maxillary lateral incisor

8. Variation in root size of the lateral incisor (that is, peg-shaped lateral incisor)

9. Variation in timing of lateral incisor root formation

10. latrogenic factors (failing to maintain space)

11. Idiopathic factors

What are the local etiologies for impacted canines?

ankylosis/impaction of the permanent canine

Ankylosis is a potential cause of prolonged retention of the primary canine, and prolonged retention may be a clinical sign suggesting __________

1. Congenital absence of the maxillary lateral incisor

2. Peg-shaped maxillary lateral incisor

3. Altered timing of lateral incisor root formation

A 12-year-old patient presents with an impacted maxillary canine. What are 3 abnormalities of the maxillary lateral incisor that have been associated with canine impaction?

1. Endocrine deficiencies (pituitary hypofunction & hypothyrodism)

2. Febrile diseases

3. Irradiation

What are the 3 systemic etiologies for impacted canines?

1. Hereditary

2. Malposed tooth germ

3. Presence of an alveolar cleft

What are the genetic etiologies for impacted canines?

2.5x

If a patient is missing their lateral incisor, what is the incidence of palatally impacted canines?

Maxillary canine loses eruption guidance owing to an absent lateral incisor

how come palatally impacted canines are more common when pts are missing their lateral incisor

proposes that the canine erupts along the root of the lateral incisor, which serves as a guide

what’s the guidance theory

genetic factors are a primary origin of palatally displaced maxillary canines and includes possibilities of other associated dental anomalies, such as missing or PEG-SHAPED lateral incisors.

what’s the genetic theory

True

T/F: It remains uncertain whether an anomalous lateral incisor is a local causal factor for palatally displaced canines or the displaced canines are the result of an associated genetic developmental influence.

1. Passed eruption time- especially if unilateral

2. Excessive distal flaring of the lateral incisors

3. Exaggerated labioversion of the laterals

What are 3 clinical signs that suggest a maxillary canine impaction?

8 years old

At what age should you start to palpate a buccal canine bulge between the lateral incisor and 1st premolar roots?

Palatal displaced cuspid

If a 10 year old patient has a lack of positive palpation of the canine buccal bulge and distal inclination of the laterals, what can you infer?

1. Lack of a distinctive cuspid bulge on the labial

2. Evidence of a palatal bulge

What are 2 clinical signs that suggest a palatally displaced maxillary canine?

Labially displaced cuspids

What do these photos suggest?

- Left - Failed to erupt

- Right - Ectopically erupted

What is the difference between the image on the left and right?

Palatally (more radiopaque, sharper, and bigger)

This image shows bilaterally impacted canines. Do you think the patient's right canine is palatally or labially displaced?

Labially (less radiopaque and smaller)

This image shows bilaterally impacted canines. Do you think the patient's left canine is palatally or labially displaced?

- Same Lingual

- Opposite Buccal

What is the SLOB rule?

Frontal and lateral cephalograms

What images can sometimes aid in the determination of the position of the impacted canine, particularly its relationship to other facial structures?

In general, it is challenging to distinguish structures based on conventional 2D radiographs, which often lead to misinterpretations.

CBCT

What images allow not only a detailed localization of impacted canines, but also their relation to adjacent teeth and THE SURROUNDING anatomical structures in the 3 Dimensions?

It is displaced totally horizontal

What do these images indicate about the canine?

- A: Canine angulation to the midline

- B: Canine angulation to the lateral incisor

What do these images indicate about the canine?

1) Ankylosis of the canine(s)

2) External or internal resorption of the cuspid

3) Formation of follicular cysts

4) Displacement

5) Dilaceration of the cuspid root

6) Loss of vitality or resorption of the adjacent teeth

What is the sequelae of impacted canines if left untreated?

2-3mm

What is the normal space needed for a dental follicle for a tooth to erupt?

12%

Resorption of the roots of the adjacent permanent incisors occur in ___% of cases of ectopic eruption of the maxillary canines in the age range 10-13 years

lateral

Of the 12% incidence of resorption, distribution of resorbed teeth is 80% _____ incisors

8 or 9 years old

At what age might it be appropriate to selectively extract maxillary deciduous (primary) cuspids for an impacted permanent canine?

91% (distal to long axis = more successful)

If a permanent canine is distal to the long axis of the primary lateral incisor and is already growing ectopically, early removal of the primary canine can result in self correction and eruption of the permanent canine ___% of the time

64% (mesial to long axis = less successful)

If a permanent canine is mesial to the long axis of the primary lateral incisor and is already growing ectopically, early removal of the primary canine can result in self correction and eruption of the permanent canine ___% of the time

the proximity of the permanent canine to the midline of the lateral root

self correction + eruption of permanent canine rate of success after early removal of primary canine depends on

True

T/F: Extraction of the primary canine (along with RPE) may offer a possibility of (78%) correcting impacted canines path of eruption

Decreased

Canine inclination (C.I.) to the midline, perpendicular distance (d) from the occlusal plane line, and zones (1-5) of the impacted canine crown. If canine angulation is more than 30 degree to the midline, the chances of spontaneous eruption after deciduous extraction are ___________

Labial impactions

(If given enough space; Palatal impactions are generally more horizontally inclined than are labial impactions and so Palatal impactions generally will not erupt on their own)

What is more likely to erupt on their own: labial or palatal impactions?

Palatal

What impaction is more horizontal: labial or palatal?

Good

What is the prognosis?

- No horizontal overlap of incisor

Average

What is the prognosis?

- Up to half root width overlap of incisor

Poor

What is the prognosis?

- Complete overlap of incisor

Good

What is the prognosis?

- Vertical Height: CEJ - halfway up root

Average

What is the prognosis?

- Vertical Height: >half

Poor

What is the prognosis?

- Vertical Height: >full root length

Good

What is the prognosis?

- Angulation: 0-15°

Average

What is the prognosis?

- Angulation: 16-30°

Poor

What is the prognosis?

- Angulation: >30°

Good

What is the prognosis?

- Position of apex: Above canine position

Average

What is the prognosis?

- Position of apex: Above 1st premolar

Poor

What is the prognosis?

- Position of apex: Above 2nd premolar

1. No treatment and periodic monitoring

2. Autotransplantation of the cuspid

3. Surgical exposure and orthodontic traction of the impacted cuspid into the occlusal plane (with or without extraction)

4. Extraction of the cuspid and space closure (substitute with first permanent premolar)

5. Extraction of the cuspid and leave the canine space for a prosthetic replacement (single implant)

What are treatment alternatives for impacted canines?

Autotransplantation

What procedure?

The atraumatic surgical removal and movement of the maxillary canine from the impaction site to the correct position within the alveolar crest

It can bring a severely impacted canine directly into the dental arch with a single surgical procedure, potentially shortening orthodontic tx time

What is an advantage of autotransplantation?

It is a complex procedure, and clinicians must consider the risks of pulpal necrosis, root resorption, and/or ankylosis

What is a disadvantage of autotransplantation?

90%

What is the success rate of autotransplantation when providers respect the protocol?

1. Functional adaptation

2. Preservation of the alveolar ridge

3. Might recover its proprioceptive function and normal periodontal support

Compared with restoration with implants, transplanted teeth have what 3 advantages?

1. The impacted canine is in favorable position

2. The impacted canine is not ankylosed

3. No resorption to any of the neighboring roots (?!)

What are the 3 indications for surgical exposure + orthodontic traction of the impacted cuspid into the occlusal plane (with or without extraction)?

This is not typically the treatment of choice except in the following instances:

1. Transposition

2. External or internal resorption

3. Ankylosis

4. Pathology

5. Severity of the impaction - depth, distance from normal position, horizontal orientation 

6. When the occlusion is perfect and the first bicuspid is in the correct position. (Removal of an impacted tooth can be indicated when clinical assessment of the treatment feasibility leads practitioners to no choice but extraction of the displaced tooth)

What are 6 instances when you should extract the impacted cuspid?

1. Maintain a Class I dental relationship

2. Align the maxillary and mandibular dental arches

3. Reduce dentoalveolar protrusion during smiling

4. Improve lip competence

5. Reduce mentalis strain

What are some treatment objectives for this case?

1. CREATE SPACE

2. Removal of any physical obstructions (supernumerary, odontoma, bone, etc)

3. Surgical exposure followed by spontaneous eruption

4. Mechanical Traction of the surgically uncovered impacted cuspids

Before deciding which treatment options to select, what are 4 diagnostic factors to consider with palatally impacted cuspids?

1. closed

2. opened w/ full flap

3. open window

3 surgical techniques used for exposing palatally impacted canines

Advantages:

- Less aggressive

- Less vertical relapse

- Better esthetic outcomes

Disadvantages:

- Tooth is invisible

- Orthodontic force cannot be controlled during traction

- Patient discomfort

- Repeat procedure if attachment/chain breaks

advantages vs. disadvantages of closed surgical technique

opened w/ full flap

which surgical technique is indicated for palatal mucosa, periosteum, and bone removal then suturing coronal to the CEJ

closed

which surgical technique is indicated for deep impacted cases

Advantages:

- Better control of the direction of traction force

Disadvantages:

- Esthetics depend on the amount of attached gingiva

advantages vs. disadvantages of opened with full flap technique

open window

which surgical technique is indicated for not deeply displaced (removal of thick palatal mucosa, bone, and follicle down to CEJ

Advantages:

- Autonomous eruption

- No traction needed

Disadvantages:

- Poor periodontium due to excessive removal of bone and tissue down to the CEJ

- Regrowth of palatal tissue

advantages vs. disadvantages of open window

Tunnel technique

What surgical technique?

Traction of the impacted tooth downward through the socket of extracted deciduous canine. Elevation of all soft tissue layers including periosteum, exposing the underlying bone

- Increased pain

- Excessive tissue removal

- Improper healing

- Damage to the periodontal attachment

- Damage to tissues and/or teeth from bonding agents

What are potential risks during surgical exposure of Palatally Impacted Canines? (5)

1. cantilever system

2. temporary anchorage devices (TADs)

3. double-archwire mechanics

3 ortho techniques to treat + manage impacted max canines

Cantilever system

What orthodontic technique to treat and manage impacted maxillary canines?

Advantages:

- Predictable tooth movement

- Low load or deflection

- Less frequent reactivations

Disadvantages:

- Potential side effects should be identified on the anchor tooth

Temporary anchorage devices (TADs)

What orthodontic technique to treat and manage impacted maxillary canines?

Advantages:

- Could provide absolute anchorage for tooth movement

- Bonding of orthodontic brackets can be delayed until the canine is aligned

Disadvantages:

- Does not produce root movement

- Insertion and removal TADs

Double-archwire mechanics

What orthodontic technique to treat and manage impacted maxillary canines?

Advantages:

- Minimizes root resorption of the lateral incisors

- Allows horizontal tooth movement

Disadvantages:

- Insertion and removal of TADs

- Requires laboratory procedure

- Patient discomfort

Ballista spring (allows tooth to move in three directions: occlusal, labial, distal)

This shows treatment of a maxillary impacted canine with what type of spring?

1. closed

2. open w/ apically positioned flap

3. gingivectomy

3 surgical techniques used to expose labially impacted canines

Closed

Which surgical technique to expose a labially impacted canine?

- Indications: Deep impacted cases, devicated from the normal position

Advantages:

- Less aggressive

- Less vertical relapse

- Less scar

- Better esthetic outcomes

Disadvantages:

- Tooth is invisible

- Orthodontic force cannot be controlled during traction

- Re-open if attachment/chain breaks

- Patient discomfort

advantages vs. disadvantages of closed technique for labially impacted canines

Open with apically positioned flap

Which surgical technique to expose a labially impacted canine?

Indications:

- Displaced above the level of the MGJ

- Either deeply impacted nor angulated proximally

Advantages:

- Preserve the keratinized tissue

- Controlled traction force direction

Disadvantages:

- Crown instability and re-intrusion of the tooth after Ortho. Tx

advantages vs. disadvantages of open w/ apically positioned flap technique for labially impacted canines

Gingivectomy

Which surgical technique to expose a labially impacted canine?

Indications:

- Palpable crown beneath attached gingiva

- Band of attached gingiva within which the incision is made, leaving a portion of the thicker tissue above the cut

Advantages:

- Easy procedure, no bone removal involved

Disadvantages:

- Clinical Attachment Loss (CAL)

- Gingival recession

advantages vs. disadvantages of gingivectomy technique for labially impacted canines

Gingivectomy

What surgical technique is recommended?

- Canine cusp is coronal to the mucogingival junction (MGJ)

Apically positioned flap

What surgical technique is recommended?

- Canine cusp is apical to the mucogingival junction (MGJ)

Closed eruption technique

What surgical technique is recommended?

- Canine cusp is significantly apical to the mucogingival junction (MGJ)

Tunnel technique

what surgical technique is used to expose midalveolar impacted canines

- Erupts the canine down through the evacuated socket of the extracted deciduous canine

- The labial part of the socket wall intact, proper attached gingiva and excellent esthetic results

describe the Tunnel technique

1. Damage to adjacent teeth

2. Improper healing

What are 2 treatment risks of surgery for impacted cuspids?

1. Damage to adjacent tissues and teeth with acid etch

2. Improper placement of attachment

3. Detachment of bracket

What are 3 treatment risks of bonding for impacted cuspids?

1. Deficient attached gingiva especially with labial cuspids

2. Gingival recession

3. Poor esthetics

4. Relapse

What are 4 treatment risks for the periodontium for impacted cuspids?

Greater, lower

An adequate zone of attached gingiva is thought to be associated with _______ ability to withstand gingival inflammation and _______ risk for developing gingival recession, while a healthy periodontium has been proposed as a key indicator of treatment success for impacted teeth

Rapid Palatal Expanders (RPE)

In children, how can you make space to allow a cuspid to erupt on its own?

For adult patients, the impacted tooth has lost its inherent eruption drive, so even if enough space is created for the impacted canine, the tooth does not erupt by itself and requires traction.

- An apically positioned flap is more predictable to increase the keratinized tissue width if there is insufficient gingiva (covering the CEJ and 2-3mm of the crown)

In adults, how can you allow a cuspid to erupt on its own?

1. Location of the impacted tooth and the distance it must travel

2. Extent of the surgical procedure required

3. Angulation of the impacted canine

4. Amount of available space in the dental arch

5. Age of the patient

6. Condition of the adjacent teeth

7. Light forces

8. The initial direction of force should be away from the roots of adjacent teeth

What are the 8 clinical considerations for impacted canines?

Light, away

When orthodontic traction is indicated, _______ forces should be used, and the initial force vector should direct the canine _______ from the roots of neighboring teeth to reduce the risk of root resorption and other complications