Maxillary Canines
Maxillary canines are the longest teeth in the mouth, with crowns that are typically as long as those of the maxillary central incisors and roots that are longer than any other teeth. As a result, they have the largest buccolingual root dimension of any tooth in the mouth. Additionally, the pulp chamber of the maxillary canine may also be the largest in the mouth due to its close correspondence to the tooth’s shape.
Morphological aspects of the root and root canal anatomy of maxillary central incisors
| Tooth notation (right/left) | (6 and 11), (3| and |3), or (#13 and #23) |
| Overall length | 26.4 mm (20.0–38.4 mm) |
| Root length | 16.5 mm (10.8–28.5 mm) |
| Complete root formation | 11.9–13.7 years (male-female) |
| Tooth axes angulation | 6° (orthoradial) and 17° (proximal) |
| Number of roots | 1 (100%)a,b |
| Apical root curvature | Straight (38.5%), distal (19.5%), buccal (12.8%), mesial (12%), palatal (6.5%), others (10.7%) |
| Root grooves | Developmental grooves on both mesial and distal sides |
| Number of canals | 1 (100%)a 1 (97%) 2 (3%)b |
| Canal configuration | Type I (100%)a Types I (98.5%), III (1.2%), II (0.8%), V (0.7%), IV (0.2%), others (0.1%)b |
| Canal cross-section | Coronal, broad buccolingually and appears ovoid; middle, oval; apical, round |
| Canal taper | BL, 0.08 mm/mm; MD, 0.05 mm/mm |
| Transverse anastomosis | – |
| Furcation canals | – |
| Apical foramen position | Central, 14%; lateral, 86% |
| Accessory canals | 3.4–30% (coronal, 0%; middle, 10%; apical, 90%) |
| Apical ramification | 15–33.8% |
| Canal curvature | Clinical view, 0–29°; proximal view, 0–33° |
| Canal diameter | BL: 0.31 mm (0.16–0.58 mm) MD: 0.29 mm (0.11–0.50 mm) |
| Anomalies | Two canals [34–36]; dens invaginatus |
| Clinical remarks | Large mid-root canal diameter becoming much narrower only in the final third near the apex; root canal cross section is usually oval-shaped, and clinician must take care to circumferentially file labially and palatally to shape and clean the canal properly; lingual shoulder should be removed as it prevents direct access to the root canal |
The access cavity begins about halfway up the crown on the palatal side. With an ovoid pulp chamber and a single horn, the access cavity is oval in outline and shape. The root canal is quite straight in the coronal and middle third and long enough to require the use of long 30-mm instruments.
