impacted canine

MANAGEMENT OF IMPACTED MAXILLARY CANINE

Presented by: Prof. Otasowie D. Osunde, BDS, FWACS, FAOCMF
Department of Oral and Maxillofacial Surgery
Faculty of Dentistry, University of Calabar, Calabar

OUTLINE

  • INTRODUCTION

  • AETIOLOGY

  • CLINICAL EXAMINATION

  • RADIOLOGICAL ASSESSMENT

  • TREATMENT OPTIONS

  • INDICATIONS FOR SURGICAL EXTRACTION

  • COMPLICATIONS

INTRODUCTION

  • A canine is considered impacted when it remains un-erupted after the completion of root development or when its contralateral tooth has erupted for at least 6 months with complete root formation.

  • Maxillary canines are the most frequently impacted teeth, following third molars.

  • The prevalence of maxillary canine impaction is roughly 2% of the population and is observed to be twice as common in females compared to males.

  • The incidence of maxillary canine impaction occurs more frequently than in the mandible, with about one-third of impacted maxillary canines located labially and two-thirds located palatally.

AETIOLOGY

Causes of impacted maxillary canine can be classified into local, systemic, or genetic factors.

LOCAL CAUSES

  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. Cysts or neoplasm.

  6. Dilaceration of the root.

  7. Absence of the maxillary lateral incisor.

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

  9. Variation in the timing of lateral incisors' root formation.

  10. Iatrogenic factors.

  11. Idiopathic factors.

SYSTEMIC CAUSES

  • Endocrine deficiencies.

  • Febrile diseases.

  • Irradiation.

GENETIC CAUSES

  • Heredity.

  • Malposed tooth germ.

  • Presence of an alveolar cleft.

Theories Associated with Palatally Displaced Canines:

  • Guidance Theory: Proposes that the canine erupts along the root of the lateral incisor, which serves as a guide. If the root of the lateral incisor is absent or malformed, the canine will not erupt.

  • Genetic Theory: Attributes the origin of palatally displaced maxillary canines to genetic factors, associated with dental anomalies like missing or small lateral incisors. Furthermore, palatally impacted maxillary canines are linked to other anomalies such as:

    • Enamel hypoplasia

    • Infra-occlusion of primary molars

    • Aplasia of second premolars

    • Small maxillary lateral incisors.

SEQUELAE OF IMPACTED MAXILLARY CANINE

  • Potential outcomes of impacted maxillary canines include:

    • Labial or lingual malpositioning of the impacted tooth.

    • Migration of neighboring teeth and consequent loss of arch length.

    • Internal resorption of teeth.

    • Formation of dentigerous cysts.

    • External root resorption of both the impacted tooth and neighboring teeth.

    • Infection, especially associated with partial eruption.

    • Referred pain and the occurrence of combinations of the above sequelae.

DIAGNOSIS OF IMPACTED MAXILLARY CANINE

The diagnosis integrates both clinical and radiographic assessments.

CLINICAL EVALUATION

Indicative Clinical Signs of Canine Impaction:

  • Delayed eruption of the permanent canine or prolonged retention of the deciduous canine beyond 14–15 years.

  • Absence of a normal labial canine bulge.

  • Presence of a palatal bulge.

  • Delayed eruption, distal tipping, or migration (splaying) of the lateral incisor.

RADIOGRAPHIC EVALUATION

Types of Radiographic Films:

  1. Periapical Films

    • Provide a two-dimensional representation of the dentition, showing the relationship of the canine to neighboring teeth in mesiodistal and superoinferior orientations.

    • For buccolingual positioning, a second periapical film should be taken using:

      • Tube-shift Technique (Clark's Rule/SLOB Rule): Two films taken with different horizontal angulations. If the object moves in the same direction as the cone, it is positioned lingually; if it moves in the opposite direction, it is positioned buccally.

  2. Buccal-Object Rule

    • Changing the vertical angulation of the cone by approximately 20° with two successive periapical films leads to opposite movements of the buccal and lingual objects.

  3. Occlusal Films

    • Assist in determining the buccolingual position of the impacted canine alongside periapical films, provided there is no superimposition on other teeth.

  4. Extraoral Films

    • Frontal and Lateral Cephalograms: Aid in determining the position relative to facial structures like the maxillary sinus and the floor of the nose.

    • Panoramic Films: Localize impacted teeth in spatial dimensions analogous to the tube-shift method.

  5. Computerized Tomography/Cone Beam CT

    • Advanced imaging allows for accurate localization and assessment of any damage to neighboring tooth roots and surrounding bone. However, limitations exist regarding cost, time, radiation exposure, and medicolegal implications.

    • Proper localization of the impacted tooth is crucial for determining surgical access, feasibility, and direction for orthodontic forces.

TREATMENT OPTIONS

  • No Treatment: Monitoring if a patient does not desire intervention. Long-term prognosis for retaining the deciduous canine is poor, as it usually requires extraction due to eventual root resorption.

  • Autotransplantation of the canine.

  • Extraction of the impacted canine with substitution using a first premolar.

  • Extraction combined with posterior segmental osteotomy, moving the buccal segment mesially to close residual space.

  • Prosthetic Replacement of the canine.

  • Surgical Exposure of the canine with orthodontic treatment to align it into the occlusion, which is the preferred approach.

INDICATIONS FOR SURGICAL EXTRACTION

Surgical extraction may be indicated due to:

  • Ankylosis.

  • Internal or external root resorption.

  • Severely dilacerated root.

  • Severe impaction (e.g., the canine is wedged between the roots of adjacent incisors, risking damage from orthodontic movement).

  • Acceptable occlusion positions the first premolar where the canine would be, achieving functional occlusion with properly aligned teeth.

  • Existence of pathologic changes such as cyst formation or infection.

  • Patient's refusal of orthodontic treatment.

COMPLICATIONS OF SURGICAL EXTRACTION

Potential complications from surgical extraction procedures include:

  • Pain.

  • Swelling.

  • Trismus.

  • Dry socket (rare).

  • Hemorrhage.

  • Delayed healing.

  • Damage to adjacent structures such as neighboring teeth, maxillary sinus, or tuberosity fractures.

  • Oro-antral fistula formation.