Podcast
Questions and Answers
What shape is the geometric outline of the tooth's mesial aspect?
What shape is the geometric outline of the tooth's mesial aspect?
What feature is present on the lingual surface of the tooth?
What feature is present on the lingual surface of the tooth?
How does the curvature of the cervical line differ between the mesial and distal aspects?
How does the curvature of the cervical line differ between the mesial and distal aspects?
What is the primary reason for the lingual convergence of the teeth?
What is the primary reason for the lingual convergence of the teeth?
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Which statement about the outline of the root is true?
Which statement about the outline of the root is true?
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What is the shape of the crown of the maxillary central incisor?
What is the shape of the crown of the maxillary central incisor?
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At what age does the maxillary central incisor typically erupt?
At what age does the maxillary central incisor typically erupt?
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Which lobe is the smallest on the newly erupted maxillary central incisor?
Which lobe is the smallest on the newly erupted maxillary central incisor?
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What feature is present on the labial surface of the maxillary central incisor?
What feature is present on the labial surface of the maxillary central incisor?
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Which contact area is located at the junction of the incisal and middle thirds of the maxillary central incisor?
Which contact area is located at the junction of the incisal and middle thirds of the maxillary central incisor?
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Study Notes
Maxillary Incisors
- Maxillary central incisor is widest mesiodistally of anterior teeth
- Chronology of maxillary central incisor:
- Appearance of dental organ: 5 months (intrauterine life)
- First evidence of calcification: 3-4 months
- Crown completed: 4-5 years
- Eruption: 7-8 years
- Root completed: 10-11 years
- All anterior teeth (incisors and canines) are formed of four lobes (three labially, one lingually)
- Maxillary central incisor is the first tooth from the midline
- Crown is the longest of all human teeth
Labial Aspect
- Geometrical outline of the crown: trapezoid shape (short side cervically, long side incisally)
- Mesial outline: straight or slightly convex, contact area with another central incisor at incisal third, mesio-incisal angle is sharp
- Distal outline: more convex, contact area with lateral incisor at the junction between middle and incisal thirds, disto-incisal angle is rounded
Contact Area
- Upper central incisors contact mesially at the midline (incisal third)
- Upper central incisors contact distally with the mesial surface of the upper lateral incisor at the junction of the incisal and middle thirds
Incisal Outline
- Newly erupted tooth has three mamelons (the middle lobe is smallest)
- After function, the incisal ridge is perpendicular to the long axis of the tooth
- Cervical line is convex toward the root
Surface Anatomy
- Elevation: labial surface is smooth and convex, maximum convexity at cervical third (cervical ridge)
- Depression: shallow 2 developmental grooves separating 3 lobes (mesio-labial and disto-labial developmental groove)
Root
- Smooth and convex
- Cone-shaped with mesial and distal outlines tapered to a blunt apex
- Apex is centralized on the long axis for extraction via rotation
Lingual Aspect
- Outline similar to labial surface, but with lingual convergence (crown and root taper lingually)
- Lingual surface of all teeth is smaller than the facial surface due to lingual convergence
- Elevations: cingulum (cervical third), mesial and distal marginal ridges, incisal ridge
- Depression: lingual fossa
Mesial Aspect
- Geometric outline: wedge (triangle) shape (base cervically, apex incisally)
- Labial outline: convex with maximum convexity at cervical third (where cervical ridge is present)
- Lingual outline: convex at cervical third (representing cingulum), then concave to the fossa, and then convex to the incisal ridge
- Cervical line: concave toward the root
- Contact area: junction of incisal and middle third (near the mesio-incisal angle)
- Root is cone-shaped with blunt apex
- Outlines taper from cervical line to blunt apex
- Line bisecting root passes from apex to incisal ridge
Distal Aspect
- Similar to mesial outline, but cervical line is shallower
- Distal contact area is more cervically located (middle third)
- Developmental groove/depression present on the root
Incisal Aspect
- Triangular shape, base labially, apex lingually
- Mesiodistal dimension greater than the labiolingual dimension
- Labial outline broad and slightly convex, tapers lingually towards cingulum (lingual convergence)
- Crown superimposes the root
- Cervical ridge (labially), cingulum, marginal ridges, incisal ridge, lingual fossa (lingually)
Maxillary Lateral Incisor Chronology
- Appearance of dental organ: 5 months
- First evidence of calcification: 10-12 months
- Crown completed: 5-6 years
- Eruption: 8-9 years
- Root completed: 11-12 years
Labial Aspect (Lateral Incisor)
- Trapezoid shape (short side cervically, long side incisally)
- Mesial outline: convex (more so than upper central), contact area at the junction of incisal and middle thirds
- Distal outline: convex (more convex than mesial), contact area at the middle third
- Incisal outline: not straight like upper central, rounded mesio-incisal and distoincisal angles
- Three mamelons present in newly erupted teeth
- Cervical line: convex toward the root
Surface Anatomy (Lateral Incisor)
- Labial surface: convex (more convex than upper central) with maximum convexity at the cervical third (cervical ridge)
- Two developmental grooves separating three lobes (mesio-labial and disto-labial)
- The root tapers gradually to the apical third, where it curves distally, and the apex is more pointed than the upper central
Lingual Aspect (Lateral Incisor)
- Similar to labial aspect, but with lingual convergence
- Elevations: cingulum (cervical third), mesial and distal marginal ridges, incisal ridge,
- Depression: lingual fossa
Clinical Considerations
- Congenitally missing lateral incisor
- Peg lateral incisor (formed of two lobes only, due to the missing of the middle lobe)
- Lingual pit and lingual groove
- Lingual tubercle (enlarged cingulum tubercle)
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Description
This quiz covers the anatomical features and developmental chronology of the maxillary central incisor. It includes details regarding its shape, contact areas, and the unique attributes that distinguish it from other anterior teeth. Test your knowledge on this fundamental aspect of dental anatomy.
