Introduction:
Teeth are an important part of the human body that helps in chewing and breaking down food for digestion. There are different types of teeth in the mouth, each with a specific function. In an adult, the teeth that are fully developed and replace the primary teeth are called permanent teeth.

Explanation:
Permanent teeth, also known as adult teeth, are the set of teeth that replace the primary teeth in the mouth. These teeth begin to erupt around the age of 6 and continue to develop until early adulthood. Permanent teeth are designed to last a lifetime and are stronger and more durable compared to primary teeth.

Function of Permanent Teeth:
Permanent teeth serve several important functions in the mouth, including:

1. Chewing: The primary function of permanent teeth is to aid in the chewing process. These teeth have a larger surface area and stronger roots, allowing for efficient grinding and breaking down of food.

2. Speech: Permanent teeth play a role in speech development. They help in the proper pronunciation of certain sounds and words.

3. Maintaining Facial Structure: Permanent teeth help in maintaining the shape and structure of the face. They provide support to the lips and cheeks, preventing sagging and a sunken appearance.

4. Maintaining Jaw Alignment: The presence of permanent teeth helps in maintaining proper alignment of the jaw. This ensures a balanced bite and prevents issues such as misalignment and malocclusion.

Types of Permanent Teeth:
There are four types of permanent teeth, each with a specific shape and function:

1. Incisors: These are the front teeth in the mouth and are used for biting and cutting food.

2. Canines: Canines are the pointed teeth on either side of the incisors. They are used for tearing and gripping food.

3. Premolars: Premolars, also known as bicuspids, are located behind the canines. They have a flat surface and are used for grinding and chewing food.

4. Molars: Molars are the largest and strongest teeth in the mouth. They are located at the back of the mouth and have a rough surface for effective grinding of food.

Conclusion:
In conclusion, permanent teeth are the fully developed teeth in the mouth that replace the primary teeth. They serve various functions and are crucial for proper chewing, speech, and maintaining the facial structure. Understanding the importance of permanent teeth and practicing good oral hygiene is essential for maintaining oral health throughout life.