Permanent Maxillary Incisors Question And Answers

The Permanent Maxillary Incisors

Question 1. Describe in detail the permanent maxillary central incisors.
Answer:

Labial aspect:

1. The mesial outline – is slightly convex.
2. The distal outline – is more convex.
3. The incisal outline – regular and straight tends to curve downward.
4. The cervical outline – is semicircular.
5. Root-cone-shaped with a blunt apex.

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Lingual aspect:

1. It shows.
2. Cingulum – smooth convexity below the cervical line.
3. Marginal ridges – Mesially and distally confluent with the cingulum.
4. Lingual fossa- Shallow concavity between the marginal ridges and below the cingulum.
   1. • It is bordered
      • Mesially by a mesial marginal ridge.
      • Incisally by a lingual portion of the incisal ridge.
      • Distally by a distal marginal ridge
      • Cervically – by cingulum.
5. Development grooves – extend from the cingulum into the lingual fossa.

• Crown and root taper lingually.
• The root is generally triangular in cross-section with rounded angles.
• One side is placed labially while the other is placed lingually.
• The mesial side of the triangle is slightly longer than the distal side.

Mesial aspect:

• The crown is wedge-shaped or triangular with the base at the cervix and an apex at the incisal edge.
• The labial outline is slightly convex.
• The lingual outline is convex at the cingulum, concave at the mesial marginal ridge, slightly convex at the lingual incisal ridge and incisal edge
• Cervical outline curves initially.
• The root is cone-shaped with a blunt apex,

Distal aspect:

• The Crown appears thicker.
• The curvature of the cervical line is less in extent.

Incisal aspect:

• The labial face is broad and flat.
• The cervical portion is convex labially.
• Incisal ridge slope lingually.
• The lingual outline tapers towards the cingulum.
• Prominent mesialabial and distolabial line angle.
• The crown shows more bulk initially.
• Broad surfaces are at contact areas.
• The incisal outline is uniform bilaterally.
• The cross-section of the root is triangular in shape.

Measurements:

• Cervicoincisal crown length: 10.5 mm
• Root length: 13 mm
• Mesiodistal crown diameter: 8.5 mm
• Mesiodistal crown diameter at cervix:
• Labio-lingual crown diameter: 7 mm
• Labio-lingual crown diameter at cervix: 6 mm
• Curvature of cervical line – mesial :3.5 mm
• The curvature of cervical line-distal: 2.5 mm

Question 2. Difference between permanent maxillary central and lateral incisor.
Answer:

Question 3. Chronology of maxillary permanent central incisor.
Answer:

• The first evidence of calcification – 3-4 months
• Crown completed- 4-5 years
• Eruption – 7-8 years
• Root completed – 10 years

Question 4. Line angles and point angles in maxillary cental incisor.
Answer:

Line angles:

• Mesiolabial, Distolabial
• Mesiolingual, distolingual
• Labioincisal, Linguoincisal.

Point angle:

• Mesiolabioincisal
• Distolabioincisal
• Mesiolinguoincisal
• Distolinguoincisal