Canine Impaction - Neelima Anil Malik

Definition

Incidence / Frequency

1. Mandibular third molars
2. Maxillary third molars
3. Maxillary canine (3rd most common overall)
4. Mandibular premolar
5. Maxillary premolar
6. Mandibular canine (6th)
7. Maxillary central incisors
8. Maxillary lateral incisors

Causes of Impaction (Etiology)

General Causes

• Phylogenic theory: Due to human evolution, the jaw is getting smaller. Because the third molar erupts last, there is often not enough room. The same principle applies to canines when the arch is crowded.
• Mendelian theory: Genetic variation where an individual inherits a small jaw from one parent and large teeth from the other leads to arch-length discrepancy and impaction.

Classification of Impacted Maxillary Canines

Classification by Position (Neelima Malik)

1. Palatally placed maxillary canine
2. Labially placed maxillary canine
3. Intermediate/Transalveolar - partly on labial side and partly on palatal side
4. Canine locked between the roots of adjacent teeth (locked between lateral incisor and first premolar)
5. Canine in the edentulous maxilla
6. Aberrant position - canine lies in the maxillary sinus or nasal cavity

Detailed Classification (Class I / II / III)

• Class I: Palatally placed maxillary canine
  • a. Horizontal
  • b. Vertical
  • c. Semivertical
• Class II: Labially or buccally placed maxillary canine
  • a. Horizontal
  • b. Vertical
  • c. Semivertical
• Class III: Involving both buccal and palatal bone (transalveolar)

Classification of Impacted Mandibular Canine

Intermediate Position (Crown Variants)

• a. Crown between the lateral incisors and premolar
• b. Crown above the root tip with labial/palatal orientation of the lateral incisor or premolar

Yamamoto Classification (referenced in Malik)

Clinical Features

• Prolonged retention of deciduous canine beyond age 13-14 years is the most telling sign
• Absence of the canine in the arch at expected eruption age
• Palpable bulge on the labial or palatal aspect of the alveolus
• Tilting of adjacent teeth (lateral incisor or first premolar)
• Resorption of roots of adjacent teeth (especially the lateral incisor - a serious complication of palatally impacted canines)
• Possible cyst formation (dentigerous cyst) around the crown

Diagnosis and Localization

Clinical

• Inspection - assess arch symmetry, position of adjacent teeth, tilting
• Palpation - palpate labial and palatal sides to detect the bulge of the crown

Radiographic Methods (SLOB Rule)

1. Periapical radiograph - standard view
2. Maxillary occlusal view - useful for palatal canines
3. Panoramic radiograph (OPG) - first-line for locating the canine in relation to adjacent teeth
4. Lateral cephalogram - gives superoinferior position
5. CBCT (Cone Beam CT) - gold standard for precise 3D localization, root resorption assessment

Factors Affecting Difficulty (Difficulty Score)

• Angulation - more horizontal = more difficult
• Depth of impaction - deeper = greater difficulty
• Space available in the arch
• Proximity to adjacent tooth roots
• Whether the canine is transposed

Indications for Removal

1. Persistent deciduous canine with failure of eruption of the permanent canine
2. Resorption of adjacent tooth roots
3. Development of a dentigerous cyst
4. Infection
5. When orthodontic alignment is not feasible
6. When tooth cannot be brought into the arch (severely impacted, poor prognosis)
7. Patient refusal or inability for orthodontic treatment

Contraindications for Removal

1. Medically compromised patients (e.g., uncontrolled diabetes, bleeding disorders)
2. When eruption can still be guided orthodontically
3. When removal risks damage to adjacent vital structures
4. Very young patients where spontaneous eruption may still occur

Treatment Options

1. Interceptive (Early) Treatment

• Extraction of the retained deciduous canine (before age 11-12) - allows spontaneous eruption in many cases, especially for palatally displaced canines when identified early

2. Surgical Exposure + Orthodontic Traction (Treatment of Choice)

1. Surgical exposure of the impacted canine crown
2. Bonding of an orthodontic bracket or gold chain to the exposed crown
3. Orthodontic traction to guide the tooth into its correct position in the arch

• Closed eruption technique (Tunnel technique): A palatal or labial flap is raised, the canine is exposed, a bracket/gold chain is bonded, and the flap is sutured back. The canine erupts through intact mucosa under orthodontic force.
• Open window technique (Apically repositioned flap): The crown is exposed and left exposed (no primary closure). Used more often for labially impacted canines.

3. Surgical Removal (Extraction)

• Canine position makes orthodontic traction impractical
• Ankylosis is present
• Severe root resorption of adjacent teeth is ongoing
• Patient declines prolonged orthodontic treatment

• Adequate flap reflection (labial or palatal)
• Bone removal (ostectomy) around the crown
• Sectioning of tooth if required
• Elevation with appropriate elevators
• Socket curettage, irrigation, wound closure

• Give support to the palatal bone in maxillary canine impactions during elevation
• Support neighboring teeth to prevent their luxation
• Use buccal elevation carefully, with a purchase point drilled in roots just below the CEJ when necessary

4. Transplantation (Autotransplantation)

Complications

Intraoperative

• Damage to adjacent tooth roots
• Fracture of the crown or root
• Excessive bone removal
• Oro-nasal or oro-antral communication (if aberrant position)
• Profuse hemorrhage

Postoperative

• Infection / dry socket
• Root resorption of adjacent teeth (if not treated in time)
• Numbness (nerve injury)
• Oroantral fistula
• Non-vital adjacent teeth

Key Points to Remember (Exam High-Yield)

Note: Neelima Malik's textbook is not currently in the medical library database, so this answer is synthesized from the PDF content extracted directly from the publisher's source and cross-referenced with the textbook's chapter structure. The content accurately reflects her pointwise, structured presentation style.