Total number of deciduous teeth in a 14 yr old child: September 2007

**Question:** Total number of deciduous teeth in a 14 yr old child

**Core Concept:** Deciduous teeth are the temporary teeth that a child grows before they are replaced by permanent teeth. These teeth serve as placeholders for the permanent teeth.

**Why the Correct Answer is Right:** In a 14-year-old child, all deciduous teeth have fallen out, and the permanent teeth have started to erupt and replace them. The total number of deciduous teeth is 20. These include 8 incisors, 4 canines, 4 premolars, and 4 molars.

**Why Each Wrong Option is Incorrect:**

A. This answer is incorrect as it refers to the number of permanent teeth, which is higher than the correct answer. In a 14-year-old child, the permanent teeth have not fully developed or erupted, hence this option is wrong.

B. This answer is incorrect as it refers to the total number of teeth in a 14-year-old child, which includes both permanent and deciduous teeth. The correct answer focuses specifically on the deciduous teeth.

C. This answer is incorrect as it refers to the number of permanent teeth in a 14-year-old child, which is higher than the correct answer. The correct answer focuses specifically on the deciduous teeth.

D. This answer is incorrect because it does not specifically mention the number of deciduous teeth. In a 14-year-old child, some deciduous teeth may still be present, while most have fallen out, making this answer incorrect.

**Clinical Pearl:**

In clinical practice, it is essential to know the number of deciduous teeth in a child to understand the timing of tooth eruption and replacement. The correct answer of 20 deciduous teeth helps dentists predict when to expect the eruption of the permanent successors and ensure proper dental care during the transition period.

**Correct Answer:** D. 20 deciduous teeth

**Explanation:** In a 14-year-old child, most deciduous teeth have fallen out, and the permanent teeth have started to erupt. The remaining deciduous teeth are:

- 2 incisors: central incisors and lateral incisors (2 in the upper jaw and 2 in the lower jaw)
- 2 canines (upper canines and lower canines)
- 2 premolars (upper and lower, 1st and 2nd)
- 1 molar (upper and lower, 1st and 2nd)

So, the correct answer is 20 deciduous teeth, which includes the 8 teeth mentioned above.