16 Questions
What is the characteristic of the canine crown from the labial aspect?
The crown is more constricted at the cervical area
How many roots does the permanent first molar have?
Three roots: lingual, mesiobuccal, and distobuccal roots
What is the characteristic of the mandibular deciduous central and lateral incisors?
They are wider mesiodistally in relation to their length
How many cusps does the permanent first molar have?
Four cusps
What is the characteristic of the mandibular deciduous canine?
The labiolingual dimension is much less than the maxillary deciduous canine
What is the characteristic of the permanent first molar from the mesial aspect?
The crown appears thicker labiolingually because of the short crown’s length
How many deciduous teeth are there in total?
20
What is the characteristic of the deciduous teeth compared to the permanent teeth?
They are smaller in all dimensions
What is the primary function of deciduous teeth in terms of mastication?
To allow proper chewing and grinding of food
At what age does the eruption of deciduous teeth start?
6.5 months
What is the sequence of tooth development stages?
Bud, cap, bell
What happens to the roots of deciduous teeth after eruption?
They start to resorb
What is the significance of deciduous teeth in terms of esthetics?
They enhance the appearance of the face
At what age is the eruption of deciduous teeth complete?
20-30 months
What is the characteristic of the mesiodistal width of maxillary deciduous central and lateral incisors?
It is more than the labiolingual dimension
What is the significance of deciduous teeth in phonetics?
They are essential for speech development
Study Notes
Tooth Development
- Tooth development occurs within the bone in the jaw and passes through stages named according to their shapes: Bud stage, Cap stage, and Bell stage.
- After the root and crown are formed, the tooth penetrates the mucous membrane and enters into the mouth by a process called “eruption”.
Eruption of Deciduous Teeth
- Sequential order of deciduous teeth according to their eruption times:
- Mandibular central incisors: 6.5 months
- Mandibular lateral incisors: 7 months
- Maxillary central incisors: 7.5 months
- Maxillary lateral incisors: 8 months
- Mandibular first molars: 12-16 months
- Maxillary first molars: 12-16 months
- Mandibular canines: 16-20 months
- Maxillary canines: 16-20 months
- Mandibular second molars: 20-30 months
- Maxillary second molars: 20-30 months
Deciduous Teeth
- Deciduous teeth are 20 in number.
- They start erupting at 6.5 months (mandibular central incisor) and finish at 20-30 months (mandibular and maxillary second molars).
- Importance of deciduous teeth:
- Allow proper mastication
- Prevent malocclusion
- Guide the eruption of permanent teeth
- Esthetics
- Phonetics
- Deciduous teeth roots are fully formed after eruption, then resorption occurs until exfoliation and eruption of permanent successor teeth.
Maxillary Deciduous Teeth
- Central and Lateral Incisors:
- Mesiodistal width is more than labiolingual dimension
- Root: crown ratio is increased
- Crown appears thicker from the mesial aspect due to short crown length
- Canine:
- Crown is more constricted at the cervical area from the labial aspect
- Mesial slope of the cusp is longer than the distal slope
- Mesial and distal contact areas are at the same level
- Root: crown ratio is increased
- Crown appears thicker labiolingually due to short crown length
- First Molar:
- Four cusps: mesiolingual (largest), mesiobuccal, distobuccal, and distolingual (smallest)
- Three roots: lingual, mesiobuccal, and distobuccal
- Second Molar:
- Five cusps: mesiolingual (largest), mesiobuccal, distobuccal, distolingual, and supplemental cusp
- Three roots: lingual, mesiobuccal, and distobuccal
Mandibular Deciduous Teeth
- Central and Lateral Incisors:
- Wider mesiodistally in relation to length than permanent mandibular incisors
- Root: crown ratio is increased
- Labiolingual width appears more due to short crown length
- Canine:
- Labiolingual dimension is much less than maxillary deciduous canine
- Cervical ridge is less pronounced than maxillary deciduous canine
- Distal slope of the cusp is larger than the mesial slope
- First Molar:
- Four cusps: mesiolingual (largest), mesiobuccal, distobuccal, and distolingual (smallest)
- Two roots: mesial and distal
- Second Molar:
- Five cusps: mesiolingual, mesiobuccal, distobuccal, distolingual, and distal cusp
- Two roots: mesial and distal
Principal Differences between Deciduous and Permanent Teeth
- Deciduous teeth are 20 in number, while permanent teeth are 32 in number.
- Deciduous teeth are smaller in all dimensions.
Learn about the stages of tooth development, including bud, cap, and bell stages, and the eruption of deciduous teeth in the correct sequence.
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