Generals of Primary Dentition
Primary Dentition
* Beginning at age 6 these teeth are gradually replaced by the permanent teeth.
* Primary teeth are often called deciduous teeth .
* From the Latin to fall off .
* nicknames are "milk teeth" or "temporary teeth".
* The teeth function an average of 8 years for maxillary teeth.
* The teeth function an average of 7.6 years for mandibular teeth.
* Hold an important role in reserving space for permanent teeth.
Eruption Time Of Primary Dentition
* First primary teeth to erupt are usually mandibular central incisors at about 6 months.
* Last teeth to erupt are the maxillary second molars around 2 and half year.
General description of primary teeth
- They have short crowns.
- They are constricted at the cervical portion.
- They have thin enamel & dentin layers.
- Enamel rods in the cervical portion extend slightly occlusally from the CEJ.
- The occlusal surface is narrow labiolingually.
- The color of primary teeth is whiter than the permanent teeth.
General description of primary teeth
Roots:
The roots of primary anterior teeth are narrow meslodistally.
The roots of primary molars are longer & more slender in relation to their crowns.
The roots of primary molars are more flare when approach to the apex.
The roots of primary anterior teeth are narrow meslodistally.
The roots of primary molars are longer & more slender in relation to their crowns.
The roots of primary molars are more flare when approach to the apex.
General Characteristics Of Primary Teeth
1) Primary teeth are smaller in size than permanent teeth.2) They are whiter in color than the analogous permanent teeth.
3) They are less mineralized than permanent teeth.
4) They have shorter crowns with respect to their roots.
5) Crowns have a marked constriction at the cervix.
6) The enamel seems to bulge close to the cervical line, rather than gradually tapering.
7) The layers of enamel and dentin are thinner than on permanent teeth.
8) The pulp cavities are proportionally larger.
9) Primary teeth exhibit fewer anomalies.
10) The crowns appear bulbous, often with labial or buccal cingula.
Primary Anterior Dentition
General Characteristics A Of The Anterior Teeth
1) Usually no depressions on the labial surface of the crowns of incisors.2) There are no mamelons on the incisal edges.
3) Facial cervical ridges are prominent.
4) Cingula are prominent and occupy 1/3 cervicoincisal length.
5) The roots are long in proportion to the crown length, and narrow mesiodistally.
6) The roots bend labially in their apical 1/3 to 1/2 as much as 10 degrees.
General Characteristics Of The Posterior Teeth
1) The molar crowns are wider mesiodistally, yet shorter cervico-occlusally.2) The second molars are much larger than the first molars.
3) The molar crowns have a narrow chewing surface.
4) The molar occlusal anatomy is shallow (cusps are short).
5) The buccal cusp tips are not pointed and their slopes meet at very obtuse angles.
6) There are few grooves or depressions in the crowns.
7) The root furcations are near the crown, with little or no root trunk.
8) The roots are widely spread beyond the outlines of the crown.
9) The roots are thin and slender.
10) The second molar roots are spread more widely than the first molar roots.
Primary Tooth Eruption Sequence
1) Central Incisors2) Lateral Incisors
3) First Molars
4) Canine
5) Second Molars