Canine Space: Management and Treatment Options
Understanding the Canine Space
The canine space refers to the anatomical region in the maxilla where the canine tooth develops and erupts, positioned between the nasal cavity, orbit, and anterior wall of the maxillary sinus, with the lateral incisor and first premolar buds located behind its palatal surface 1.
Diagnostic Imaging Approach
Start with orthopantomography (OPT) as the first-line diagnostic examination for suspected canine impaction or space-related issues 2.
Initial Assessment (Level I Imaging)
- Do not perform radiological examination before age 6, as permanent tooth buds (except third molars) become visible on panoramic images at this age 2
- OPT provides adequate information on canine position, relationship with the alveolar ridge, projective relationships with adjacent teeth, and presence of associated lesions 2
- Periapical radiography may supplement OPT for upper incisor-canine region assessment, though its anatomical vision is restricted 2
Advanced Imaging (Level II - CBCT)
Reserve CBCT for cases where 2D imaging cannot provide adequate information, following the ALARA principle with targeted, limited field-of-view scans 2.
CBCT is specifically indicated when:
- OPT suggests contact between impacted canines and critical structures 2
- Root resorption of lateral incisors by impacted canines needs assessment, as OPT significantly underestimates both detection and severity 2, 3
- Precise 3D localization is required for surgical planning 2
Critical caveat: Level I radiographic investigations detect only 5.31% of external root resorption compared to 22.88% detected by CBCT, making them inadequate for characterizing root resorption 3.
Space Analysis and Etiology
Palatally Impacted Canines
85% of palatally impacted canines have sufficient space for eruption, indicating that arch-length deficiency is not the primary etiologic factor 1.
Palatal impaction occurs when extra space exists in maxillary bone from:
- Excessive growth in the maxillary base 1
- Agenesis or peg-shaped lateral incisors creating available space 1
- Stimulated eruption of lateral incisors or first premolars 1
- Dysplasia in the maxillary-premaxillary suture 1
Labially Impacted Canines
Labially located ectopic canines demonstrate significantly less available space and are associated with broader lateral incisors (average 0.65 mm wider, 95% CI: 0.25-1.05) compared to palatally impacted cases 4.
Treatment Planning Algorithm
For Palatally Impacted Canines with Adequate Space
Identify dental morphology deviations using OPT to classify cases:
- Group I: Normal morphology
- Group IIa: Deviations within maxillary incisors only
- Group IIb: General dental deviations 4
Cases with general dental deviations (Group IIb) have significantly more space and may require different surgical approaches 4
For Space Closure After Extraction
Orthodontic space closure with first premolar intrusion and canine extrusion does not increase risk for periodontal deterioration or temporomandibular disorder long-term 5.
When performing en-masse retraction:
- Interseptal bone reduction distal to maxillary canines accelerates retraction rate by 0.26 mm/month (95% CI: 0.17-0.34), though clinical significance is minimal 6
- This technique does not affect canine angulation or increase root resorption risk 6
Common Pitfalls to Avoid
- Never rely solely on OPT for root resorption assessment, as it dramatically underestimates both presence and severity 2, 3
- Avoid CBCT as initial diagnostic examination unless specific indications exist, to minimize radiation exposure 2
- Do not assume arch-length deficiency as the primary cause of palatal canine impaction, as most cases have adequate space 1
- Recognize that canines cannot "jump" anatomical structures (nasal cavity, sinus, adjacent tooth buds) to become palatally impacted; they require available space to "dive" into bone 1