Final answer:
A matrix band is used to maintain proper contact during tooth restoration, while a gomphosis refers to the joint anchoring teeth in the jaw, held by the periodontal ligament.
Step-by-step explanation:
A matrix band acts as an artificial wall to keep proper contact between the tooth/teeth being restored and the adjacent tooth. When restoring a tooth, particularly with an amalgam or composite filling, a matrix band can be placed around the tooth to create a temporary wall against which the restorative material can be packed. This helps to re-establish the natural shape of the tooth and prevents the filling material from overflowing to the adjacent teeth.
The term gomphosis refers to the specialized fibrous joint that anchors the root of a tooth into its bony socket within the maxillary or mandible bone. It is also known as a peg-and-socket joint. The periodontal ligament is a key component of this joint, providing both attachment and cushioning between the tooth and the socket.