Humans exhibit two sets of teeth, primary teeth and permanent teeth. Primary dentition erupts first in the oral cavity and is replaced by permanent dentition. The difference between the primary and permanent teeth is given below.
1. Primary teeth are smaller in overall size than the analogous permanent teeth.
2. The colour of the enamel is whiter in primary teeth than the permanent teeth. The tooth colour depends upon the level of mineralization of enamel. The deciduous teeth have less mineralized enamel, which is more opaque and whiter. Highly mineralized enamel is very translucent and the underlying dentin can be seen through the enamel and impart and yellowish tinge to the tooth.
3. The crowns of primary teeth are wider mesiodistally than they are occluso-cervically. Therefore, they are more bulbous than their permanent successors.
4. Primary teeth have a marked cervical prominence, especially on the buccal aspect of primary molars.
5. Primary teeth show a greater degree of attrition than that shown by permanent teeth. Attrition depends upon the level of mineralization of the enamel. More highly mineralized enamel is harder and so is more slowly worn away than less mineralized enamel.
6. Depth of enamel is more constant and thinner in the primary teeth than in permanent teeth.
7. The incisal edges of deciduous incisors show no mamelons.
8. The contact areas between deciduous molars are broader, flater and situated more gingivally than those between permanent molars.
9. The second deciduous molars are decidedly larger than the first molars whereas reverse is true for permanent dentition.
10. Microscopically, the enamel rods in the gingival one-third of the deciduous molars as they proceed towards the enamel surface incline towards the occlusal, compared to the permanent teeth, where these rods incline cervically.
11. Roots of the primary teeth are longer and thinner mesiodistally in comparison with crown size than those of the permanent.
12. The roots of deciduous teeth are fully formed about one year after eruption whereas the roots of permanent teeth take a longer duration about 3 years.
13. Roots of the primary teeth undergo physiologic resorption, where as in the permanent teeth the resorption is pathologic.
14. Pulp horns of primary teeth are more prominent and are higher in primary molar.
15. Primary pulp ages at a faster rate than the permanent pulp.
16. The radicular pulp of the primary molars follows a thin, tortuous and branching path.
17. There are no clearly defined root canal entrances in primary teeth.
Important Questions for Objective Type Exams:
Q: How many sets of teeth humans exhibit?
Ans: 2
Q: Why primary teeth are more whiter than permanent teeth?
Ans: The deciduous teeth have less mineralized enamel, which is more opaque and whiter.
Q: The tooth colour depends upon the?
Ans: Level of mineralization of the enamel.
Q: Highly mineralized enamel is?
Ans: Very translucent.
Q: Why primary teeth are more bulbous than permanent teeth?
Ans: Because crowns of primary teeth are wider mesiodistally than they are occluso-cervically.
Q: Which set of teeth show greater degree of attrition?
Ans: Primary teeth
Q: Why primary teeth show greater degree of attrition than permanent teeth?
Ans: Attrition depends upon the level of mineralization of the enamel. More highly mineralized enamel is harder and so is more slowly worn away than less mineralized enamel.
Q: Which type of resorption takes places in primary teeth?
Ans: Physiologic resorption.
Q: Which type of resorption takes place in permanent teeth?
Ans: Pathologic resorption.
Q: Which type of pulp ages faster?
Ans: Primary pulp.
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