## **Core Concept**
Root development, or root completion, in teeth is a significant aspect of dental anatomy and is crucial for understanding dental growth and development. The process of root formation, also known as root morphogenesis, involves the coordinated action of various cell types and tissues. For permanent teeth, including the maxillary lateral incisor, root completion typically occurs after the tooth has erupted into the oral cavity.

## **Why the Correct Answer is Right**
The maxillary lateral incisor, like other permanent teeth, follows a general timeline for root development. Generally, root formation starts after the crown is fully formed and begins to erupt. For maxillary lateral incisors, which typically erupt between the ages of 8 to 9 years, root completion is expected to occur a few years post-eruption. Studies and dental anatomy references often cite that root completion for maxillary lateral incisors occurs around 12 to 13 years of age. Therefore, option **C. 12-13 years** aligns with established dental developmental milestones.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option suggests an age that seems too early for root completion of a maxillary lateral incisor, given that root development starts after eruption and takes a few years to complete.
- **Option B:** While closer, this age might still be on the early side for complete root formation of a maxillary lateral incisor, considering typical developmental timelines.
- **Option D:** This option suggests an age that is generally later than what is typically cited for root completion of maxillary lateral incisors.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that root development can vary among individuals and between different teeth. However, for the maxillary lateral incisor, a commonly cited age for root completion is around **12-13 years**. Understanding these developmental milestones is crucial for dental diagnosis, treatment planning, and assessing dental maturity.

## **Correct Answer:** C. 12-13 years