Anatomy of Primary Dentition Flashcards
What is one essential function of primary teeth related to food intake?
They are needed for mastication (chewing)
How do primary teeth support facial appearance?
They support the cheeks and lips, contributing to a normal facial appearance.
Why are primary teeth important for speech development?
They help in forming sounds and are necessary for speech development.
What role do primary teeth play for permanent teeth?
They act as space maintainers for permanent teeth, guiding their eruption.
Exfoliation
the process by which primary (deciduous) teeth fall out and are replaced by permanent teeth
What is the consequence of early exfoliation or extraction of primary teeth?
It can lead to orthodontic problems due to loss of space for permanent teeth.
What dental device may be used if primary teeth are lost prematurely?
Space maintainers may be used to prevent loss of space.
How does caries progression in primary teeth compare to that in permanent teeth?
Caries progresses faster in primary teeth (Vanderas, 2004).
What is the primary dentition period?
The period from approximately 6 months until about 6 years old.
What is mixed dentition?
The period between 6 to 12 years old when both primary and permanent teeth are present.
What is exfoliation in dental terms?
The process of primary teeth being lost or shed.
What are succedaneous teeth?
Teeth that replace primary teeth.
What are nonsuccedaneous teeth?
Permanent maxillary and mandibular first, second, and third molars, which do not replace primary teeth.
When does the adult dentition period typically begin?
Around age 12, when all primary teeth have usually been replaced by permanent teeth.
How many teeth are in the primary dentition?
20 teeth
How many incisors are in the primary dentition?
8 incisors
How many canines are in the primary dentition?
4 canines
How many molars are in the primary dentition?
8 molars
Are there premolars in the primary dentition?
no premolars in primary dentition
How does the variability of primary dentition compare to permanent dentition?
primary dentition shows less variability than the permanent dentition
What numbering system is commonly used for primary dentition in the United States and most commonly used by insurance companies?
The Universal Numbering System.
What other numbering system can be used for the primary dentition?
Palmer Numbering System
How are primary teeth labeled in the Universal Numbering System?
By letters A to T.
In the Universal Numbering System, what letters represent the maxillary (upper) primary teeth?
A to J
In the Universal Numbering System, what letters represent the mandibular (lower) primary teeth?
K to T
How are supernumerary primary teeth designated?
By adding an “S” to the end of the letter of the most adjacent tooth. (Example: DS)
How are supernumerary permanent teeth designated?
By adding 50 to the number of the most adjacent tooth. (Example: 59)
How does the volume and exposed enamel area of primary teeth compare to that of permanent teeth?
Primary teeth have about half the volume and exposed enamel area of their permanent successors.
How do the primary incisors and canines compare mesiodistally to their permanent successors?
They are narrower mesio-distally than the permanent incisors and canines.
How do the primary molars compare mesiodistally to the permanent premolars?
Primary molars are wider mesiodistally than their permanent successors, the premolars.
What is “Primate Space” in primary dentition?
Natural spacing found mesial to the maxillary canines and distal to the mandibular canines.
What is “Leeway Space”?
The mesio-distal width difference between primary molars and their permanent replacements (premolars).
How much leeway space is typically found in the upper arch per quadrant?
Between 0.9 to 1.1 mm per quadrant.
How much leeway space is typically found in the lower arch per quadrant?
Between 1.7 to 2.4 mm per quadrant.
Why is leeway space important in orthodontics?
If there is about 4 mm of crowding per arch (or 2 mm per quadrant), comprehensive orthodontic treatment is often recommended.
Why are primary teeth smaller than permanent teeth?
To compensate for the smaller jaw in which they must erupt and function.
Baume Type 1 spacing
ideal spacing between primary teeth
Baume Type 2 spacing
limited/no spacing between primary teeth
In general, who experiences primary tooth eruption earlier, girls or boys?
Girls tend to experience primary tooth eruption earlier than boys.
How do primary teeth tend to erupt?
Primary teeth tend to erupt in pairs.
Which teeth typically erupt first, mandibular or maxillary teeth?
Mandibular teeth tend to erupt before maxillary teeth.
When does the first primary tooth typically erupt?
around the 6th to 7th month with the mandibular incisors
What tint do primary teeth generally have?
Primary teeth tend to have a bluish-white tint.
How does the color of primary teeth compare to that of permanent teeth?
Primary teeth are noticeably whiter, while permanent teeth are more gray or yellow in color.
How does the thickness of dentin and enamel in primary teeth compare to permanent teeth?
about half as thick in primary teeth
What is the general shape of primary tooth crowns?
Small, bulbous crowns with sharp constriction at the CEJ, known as “rubber band” constriction.
What feature is present on the labial or buccal surfaces of primary teeth?
A sharp lingual inclination occlusally, forming a distinct labiogingival or buccogingival ridge that ends at the CEJ.
Why are primary teeth described as having “bell-shaped” crowns?
Due to their gingival bulge, which influences preparation for restorations.
What clinical challenge is posed by the crown morphology of primary teeth?
Matrix band adaptation is difficult because of the constriction at the CEJ.
How do the roots of primary teeth compare to those of permanent teeth?
more slender, tapering, and longer in proportion to the crown
What is a distinguishing feature of the root structure in primary molars?
lack an identifiable root trunk, and their roots diverge more
Why must care be taken when extracting primary molars with unresorbed or partially resorbed roots?
to prevent damage to the underlying permanent tooth.
How does the pulpal outline of primary teeth compare to that of permanent teeth?
it follows the DEJ (dentino-enamel junction) more closely
How does the pulp in primary teeth compare proportionally to permanent teeth?
larger and closer to the enamel surface in primary teeth.
How do the pulpal horns in primary teeth compare to the cusps?
longer and more pointed than the cusps suggest.
Why is the pulp larger in primary teeth than in permanent teeth?
The dentin is thinner, making the pulp proportionately larger in primary teeth.
How are the pulp canals of primary molars described?
slender, tapering, and have fans of tissue between the roots.
What challenge is associated with performing root canal therapy on primary teeth?
The canal space is not readily filled when root canal therapy is indicated due to the narrow, tapered pulp canals.
What is the composition of enamel
long, thin rods of hydroxyapatite crystalline structure and type 1 collagen.
How thick is the enamel in primary teeth compared to permanent teeth?
half the thickness (and volume) of the enamel in permanent teeth.
How is the thickness of primary enamel described?
generally uniform, with the surface parallel to the DEJ (dentino-enamel junction).
What makes prenatal enamel in primary teeth unique?
more homogeneous and may contribute to the bluish-white color of primary enamel.
How does the dentin in primary teeth compare to permanent teeth in terms of ease of cutting?
Dentin in primary teeth is easier to cut
How does dentin in primary teeth differ in terms of abrasion?
Dentin in primary teeth abrades more quickly
What is the color of dentin in primary teeth?
light yellow.
How does decay progress in primary teeth compared to permanent teeth?
Decay progresses faster in primary teeth due to thinner dentin.
Why do primary teeth experience more attrition?
They are less mineralized.
How do primary teeth experience more attrition?
wear from tooth-to-tooth contact
What appearance can primary anterior teeth have due to attrition?
anterior teeth may have a short, stubby appearance due to attrition.
How does the occlusal surface of primary molars compare to permanent molars?
flat occlusal table, lacking the characteristic inclined plane seen in permanent molars.
How do the crowns of primary anterior teeth compare in size?
broader and shorter
What is a distinctive feature of the facial surfaces of primary anterior teeth?
smooth facial surfaces with no mamelons.
How do the roots of primary anterior teeth appear from the proximal view?
long and narrow.
What is a characteristic of the roots of primary anterior teeth?
roots bend 10° labially.
Do primary anterior teeth have grooves and depressions?
A few.
How are the incisal edges of primary incisors shaped?
flat mesially and convex distally.
How do primary central incisors compare in width and length?
wider mesiodistally than longer incisocervically.
How do primary lateral incisors compare in length?
longer incisocervically (I-C) than primary central incisors.
How do primary incisors appear in older children?
stubby due to relatively rapid wear through attrition.
What shape is the crown of a primary canine?
pentagon-shaped.
How do primary canines compare to permanent canines in shape?
more slender and conical
How do the dimensions of primary canines compare?
are as wide as they are long.
What is the relationship between the cusp ridges on primary canines?
mesial cusp ridge is LONGER than the distal cusp ridge.
How do mandibular primary canines compare in size?
Mandibular primary canines are LONGER incisocervically and NARROWER mesiodistally than maxillary canines.
How do the pulps of primary molars compare to permanent molars?
long mesial pulpal horns, closer to the mesial surface.
How do the contact areas of primary molars differ from permanent molars?
broad and flat contact areas.
How do maxillary and mandibular primary molars differ?
MAX molars are wider bucco-lingually; MAND molars are wider mesiodistally.
How do primary second molars compare to permanent first molars?
resemble permanent first molars but are smaller with more gingival constriction and a bulge in the gingival third.
How do primary second molars compare in size to second premolars?
larger than their permanent successors, the second premolars.
How many cusps does the mandibular first primary molar have?
4 cusps
What is the result of the lingual inclination of the buccal cusps on the mandibular first primary molar?
creates a prominent cervical bulge.
How does the bucco-lingual width of the occlusal table of the mandibular first primary molar compare?
The bucco-lingual width of the occlusal table is narrow
What ridge is found on the mandibular first primary molar?
A transverse ridge runs from the mesiolingual (ML) to the mesiobuccal (MB) cusp.
What is missing on the occlusal surface of the mandibular first primary molar?
It does not have a central fossa.
What feature is prominent on the mesial side of the mandibular first primary molar?
The large mesial marginal ridge.
What is the failure rate for class II restorations on mandibular first primary molars?
highest failure rate for class II restorations.
How many cusps does the maxillary first primary molar have?
3 cusps
What is the shape of the crown of the maxillary first primary molar?
resembles the form of a premolar.
How does the buccal width of the maxillary first primary molar compare to the lingual width?
buccal width is GREATER than the lingual width, giving the occlusal surface a triangular outline.
How many roots does the maxillary first primary molar have?
3 roots
How does the size of the maxillary first primary molar compare to its permanent successor?
larger than its permanent successor.
What connects the distobuccal and mesiolingual cusps on the maxillary first primary molar?
oblique ridge.
What are the last primary tooth to erupt
A and #J
