Final answer:
A class III occlusion is characterized by a concave facial profile and an underbite, with associated features like a thin upper lip and indistinct philtrum. It includes the lower teeth and jaw being positioned in front of the upper teeth and jaw.
Step-by-step explanation:
A class III occlusion, often associated with a 'concave facial profile,' is where the lower teeth and jaw protrude in front of the upper teeth and jaw. This is also known as an underbite. In individuals with a class III occlusion, you may notice features such as a below-average head circumference, smaller than average eye openings with skin folds at the corners of the eyes, a low nasal bridge, a short nose, and a smaller than average midface size. Additionally, there may be a thin upper lip and an indistinct philtrum.
When examining occlusion, it's also helpful to understand the types of teeth in your mouth. If you look in the mirror, you can find your incisors which are the front teeth designed for cutting, canines that are pointed for tearing, bicuspids which crush and tear, and molars that are used for grinding food.