A 6 months old child does not have any tooth in mouth. Normally by what maximum age first tooth should erupt.
**Core Concept**
The eruption of primary teeth, also known as baby teeth, is a significant milestone in a child's dental development. The timing of tooth eruption can vary, but there is a generally accepted age range for the first tooth to appear. This process is influenced by genetic and environmental factors.
**Why the Correct Answer is Right**
The eruption of the first tooth, typically the lower central incisor, usually occurs between 6-12 months of age. This is a critical period in a child's oral development, and delays or absence of tooth eruption can be indicative of underlying health issues. Factors such as genetics, nutrition, and overall health can affect the timing of tooth eruption.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as the first tooth typically erupts before 6 months of age.
* **Option B:** This option is incorrect as the first tooth typically erupts before 12 months of age.
* **Option C:** This option is incorrect as there is no established upper limit for the eruption of the first tooth, but it is generally accepted to be before 12 months.
* **Option D:** This option is incorrect as there is no established lower limit for the eruption of the first tooth, but it is generally accepted to be after 6 months.
**Clinical Pearl / High-Yield Fact**
A delay in tooth eruption can be a sign of underlying health issues, such as hypothyroidism, vitamin D deficiency, or genetic disorders. Therefore, it is essential to monitor a child's dental development and consult a pediatrician if there are concerns.
**Correct Answer: C. 12 months**