Permanent Canines PDF

DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Permanent canines General features: ✓ Human canines are the longest and most stable teeth in the dental arch. ✓ Their roots are the longest and thickest “labio-lingually”. ✓ Last teeth to be lost. ✓ They are ref...

DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Permanent canines General features: ✓ Human canines are the longest and most stable teeth in the dental arch. ✓ Their roots are the longest and thickest “labio-lingually”. ✓ Last teeth to be lost. ✓ They are referred to as the “corner stones” of the dental arches- help to support the facial musculature. ✓ Both maxillary and mandibular canines have the canine eminence which is the bone ridge over the labial portions of the roots. ✓ They are the only teeth in the dentition with a single cusp. ✓ It differs from incisors in the aspect of having a cusp (so, it is called cuspid) instead of incisal edge. ✓ Support the incisors and the premolars thus it makes a smooth transition from anterior to posterior. 25  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Maxillary canine Chronology First evidence of calcification 4-5 m. Crown completed 6-7 y. Eruption 11-12 y Root completion 13-15 y Labial aspect ✓ Geometric out line: Trapezoidal. ✓ The mesial outline: Convex from the cervix to the center of the mesial contact area. ✓ The distal outline: Usually concave between the cervical line and the distal contact area. ✓ Contact areas: Mesially: at the junction of middle and incisal thirds Distally: at the center of the middle third of the crown. ✓ The cusp: The cusp tip is on a line with the center of the root. The cusp has a mesial slope and a distal slope, the mesial slope being shorter than distal one. Both slopes show a tendency toward concavity 26  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR ✓ Surface description The labial ridge: The middle labial lobe shows much greater development than the other lobes. This produces a ridge on the labial surface of the crown. ✓ Cervical line: convex root wise. ✓ The root: Appears conical in form with a bluntly pointed apex. Mostly curved distally in the apical third. 27  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Lingual aspect ✓ All outlines are reversed. ✓ There is lingual convergence. ✓ Surface description. 1. Elevations The cingulum is large, smooth, well- developed occupying the cervical portion. It is largest of all anterior teeth. The marginal ridges are strongly developed. Lingual ridge divides the lingual fossa into 2 fossae. 2. Depressions The lingual fossa is more concave and may be divided by a lingual ridge into two small concavities called mesial and distal lingual fossae. 28  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Mesial aspect ✓ Geometric outline. Triangular with its apex at the cervical line. ✓ Labial outline Convex. The crest of curvature at the junction between middle and cervical thirds. ✓ Lingual outline Convex line describing the cingulum, then convexity straightens out as the middle third is reached, becoming convex again in the incisal third. The crest of curvature is at the middle of the cervical third. ✓ The cusp o Labial to a line bisecting the root. ✓ Cervical outline o Concave root wise. ✓ Surface description o Generally convex except for a small concavity in the cervical portion above the contact area. ✓ The root o Conical, with a tapered or bluntly pointed apex with a shallow developmental depression. 29  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Distal aspect ✓ The distal aspect is similar to the mesial aspect except for the following features: o The cervical line is less curved on the distal surface o The distal marginal ridge is strongly developed than the mesial. o Deeper developmental depression on the root surface. 30  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Incisal aspect ✓ Geometric outline o Diamond in shape o The labiolingual dimension is greater than the mesiodistal. ✓ The tip of the cusp is labial to the center of the crown labiolingually. ✓ The labial ridge is very noticeable. ✓ The cingulum makes a short convex arc at the cervical third. 31  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Mandibular canine Chronology First evidence of calcification 4-5 m. Crown completed 6-7 y. Eruption 9-10 y Root completion 12-14 y General features: The mandibular canine crown is narrower mesiodistally than that of the maxillary canine. The root is somewhat shorter. The labiolingual diameter of crown and root is small. The lingual surface of the crown is smoother, with less cingulum development and less bulk to the marginal ridges. The cusp of the mandibular canine is not as well developed as that of the maxillary canine. Usually, the cusp tip lies lingual to the line, as with the mandibular incisors. 32  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Labial aspect ✓ Geometric outline Trapezoid with the smallest side at the cervical line and the larger side at the incisal ridge. ✓ The mesial outline Nearly straight with the mesial outline of the root. ✓ The distal outline Convex. ✓ Contact areas Mesially: at the middle of the incisal third. Distally: at the junction between middle and incisal thirds. ✓ The cusp: Cusp tip is centered. The mesial slop is shorter than distal. ✓ The cervical line: Convex root wise. ✓ The root Shorter by l or 2 mm on average than that of the maxillary canine. Apical end is distally curved. 33 DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR 34  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Lingual aspect ✓ All outlines are reversed. ✓ There is lingual convergence. ✓ Surface description. The lingual surface is flatter, simulating the lingual surfaces of mandibular incisors. The cingulum is smooth and poorly developed. The marginal ridges are less distinct. The lingual ridge is shallow except toward the cusp tip; where it is raised. Two small lingual fossae. 35  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Mesial aspect ✓ Geometric outline Triangular with the base toward the cervical line. ✓ Labial outline Less convex especially near the cervical line. The crest of curvature is at the junctions between middle and cervical thirds. ✓ Lingual outline Less convex cingulum and less concave lingual fossa. The crest of curvature is at the middle of the cervical third. ✓ The cusp Lingual to the line bisecting the tooth. ✓ Cervical outline: Concave root wise. ✓ The root Similar to the maxillary canine. More pointed root apex. Deeper developmental depression than that of max. canine. 36  DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR Distal aspect ✓ The distal aspect is similar to the mesial aspect except for the following features: o The cervical line is less curved on the distal surface o Deeper developmental depression on the root surface. Incisal aspect ✓ Geometric shape: Oval ✓ Incisal aspect is similar to that of maxillary canine except the following features: o Cingulum is smaller. o Cusp tip is lingually inclined. 37 DENTAL ANATOMY AND OCCLUSION/ DR. MONA DENEWAR 38