Tooth Morphology .PPT, POWER POINT SLIDE ON TOOTH MORPHOLOGY
There is a certain amount of variation among individual teeth based on factors such as race, ethnicity, sex, and age. Not every tooth will meet all the criteria for identification. By understanding the characteristics of each tooth, you can differentiate between teeth and distinguish between left and right teeth in any particular group.
Clinical Uses for Tooth Morphology
- Mounting dental radiographs.
- Assisting in charting a mouth with missing teeth and
teeth that have “drifted.”
- Selecting temporary crowns from a variety of shapes.
- Forming matrix bands before application.
Anterior
Permanent Dentition
There are 12 anterior teeth in the
permanent dentition, six in each dental arch. The permanent anterior teeth
include the central incisors, lateral incisors, and canines. These teeth are succedaneous,
replacing the corresponding primary teeth.
Characteristics of Permanent Anterior Teeth
- All anterior teeth have a cingulum, a rounded
raised area on the cervical third of the lingual surface, corresponding to
the lingual developmental lobe.
- The lingual surface of anterior teeth has rounded,
raised borders called marginal ridges.
- Some anterior teeth have a fossa, which is a
wide, shallow depression on the lingual surface.
Maxillary Central Incisors
- The maxillary central incisors (#8 and #9) are
larger compared to the mandibular central incisors, especially
mediodistally.
- They have a more rounded labial surface and a
relatively short root.
- Lingual surface features (marginal ridges, lingual
fossa, cingulum) are more prominent compared to mandibular incisors.
Additional
Characteristics:
- The incisal edge is formed at the labioincisal
line angle and wears down over time.
- Mamelons (rounded enamel extensions on the incisal
ridge) are present upon eruption but usually undergo attrition.
Maxillary
Lateral Incisors
- Smaller than the central incisors, with a single root
that may curve slightly to the distal.
- Vary in form more than any other tooth except the third
molars, making them challenging in preventive, restorative, and
orthodontic procedures.
- Frequently congenitally missing.
Mandibular Permanent Incisors
- The smallest and most symmetric teeth in the permanent
dentition.
- The central and lateral mandibular incisors resemble
each other, with the lateral incisor being slightly larger.
- They tend to collect supragingival deposits such as
plaque and calculus due to their lingual concavity.
Mandibular Central Incisors
- Narrower on the lingual surface than the labial
surface.
- They lack prominent developmental features like
imbrication lines and developmental depressions.
🦷 Permanent Canines
The four canines in the permanent
dentition are located at the corners of each quadrant of both dental arches.
Canines resemble the teeth of dogs, which is reflected in their name.
Characteristics of Permanent Canines
- Longest teeth
in the dentition with roots typically one times the length of the crown.
- Known for the canine eminence, a bony ridge
overlying the root of the canine.
Maxillary
Canines
- Maxillary canines
(#6 and #11) usually erupt after the incisors.
- They are characterized by a sharper cusp tip, and the
mesial cusp slope is typically shorter than the distal cusp slope.
Clinical
Considerations:
- Maxillary canines may erupt labially or lingually
relative to the surrounding teeth.
- They may remain impacted if there is insufficient space
due to late eruption after the incisors.
Mandibular Canines
- Mandibular canines
(#22 and #27) resemble maxillary canines but are narrower labiolingually
and mesiodistally.
- The lingual surface is smoother with a less developed
cingulum compared to the maxillary canine.
🦷 Posterior Permanent Dentition
The posterior teeth consist of premolars
and molars, which have occlusal surfaces bordered by marginal ridges and
multiple cusps. These cusps are sloped areas, with cuspal planes between
them.
Features
of Posterior Teeth
- Fossae
(shallow depressions) are present on occlusal surfaces. The central
fossa is where cusp ridges meet, while triangular fossae are
smaller.
- Occlusal pits
are sharp pinpoint depressions found at the convergence of grooves.
Clinical Considerations:
- Posterior teeth have pit and groove patterns,
making them susceptible to caries due to plaque retention and enamel
thinning in pits and grooves. Sealants are recommended after eruption to
prevent decay.
Permanent
Premolars
There are eight premolars in the
permanent dentition, two in each quadrant. They are located posterior to the
canines and anterior to the molars.
Maxillary First Premolars
- Larger than the second premolars, with two roots (buccal
and lingual).
- The root is bifurcated, with some instances of fused
roots.
Mandibular
Premolars
- The mandibular first premolars (#21 and #28) are
smaller, with a well-formed buccal cusp and a small non-functioning
lingual cusp.
- The mandibular second premolars (#20 and #29)
come in two forms: three-cusp and two-cusp types.
🦷 Permanent Molars
There are 12 molars in the permanent
dentition, typically three in each quadrant. These have four or five short,
blunt cusps, and two or three roots supporting the crown.
Maxillary Molars
- The maxillary first molars (#3 and #14) are the
largest in the maxillary arch, consisting of five lobes with a fifth cusp
known as the cusp of Carabelli.
- The maxillary second molars are slightly smaller
with four cusps and three roots.
Maxillary
Third Molars
- These molars are smaller with fused roots and are often
referred to as wisdom teeth because they erupt last.
Mandibular
Molars
- Mandibular first molars (#19 and #30) erupt between 6-7 years of age.
- Mandibular second molars (#18 and #31) erupt between 11-12 years of age and are
nonsuccedaneous, replacing the primary mandibular second molars.
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