Final answer:
Teeth are held in place by a joint called a gomphosis, which consists of periodontal ligaments connecting the tooth root to the socket walls. Gomphosis joints are immobile, making them synarthrosis joints.
Step-by-step explanation:
Teeth are held in place by a specialized type of joint called a gomphosis or peg-and-socket joint. A gomphosis is a fibrous joint that anchors the root of a tooth into its bony socket within the upper or lower jaw. It is composed of short bands of dense connective tissue called periodontal ligaments that span between the socket walls and the tooth root. The immobility of a gomphosis makes it functionally classified as a synarthrosis joint.