Anatomy and Occlusion Flashcards

Which muscle is the PRIMARY muscle responsible for closing the mandible (elevating)?

Answer: Masseter

The masseter is the most powerful jaw-closing (elevator) muscle and is readily palpable on the lateral face during clenching.

Identify the tooth surface facing the tongue on mandibular posterior teeth:

Answer: Lingual

The lingual surface of mandibular teeth faces the tongue; palatal is only used for maxillary teeth surfaces facing the palate.

A patient presents with wear on the lingual surfaces of maxillary anterior teeth. This pattern is MOST associated with:

Answer: Acid erosion from frequent vomiting or GERD

Palatal/lingual erosion of maxillary anterior teeth is a hallmark of acid erosion from intrinsic sources such as GERD or bulimia.

The mandibular premolars differ from maxillary premolars in that they typically have:

Answer: One root and one or two cusps

Mandibular premolars most often have a single root; the first mandibular premolar has a dominant buccal cusp with a small lingual cusp, while the second may have two lingual cusps.

Which structure forms the posterior boundary of the hard palate?

Answer: Posterior nasal spine

The posterior nasal spine is the bony landmark that marks the posterior boundary of the hard palate where it meets the soft palate.

In an ideal Class I occlusion, the mesiobuccal cusp of the maxillary first molar occludes in the:

Answer: Buccal groove of the mandibular first molar

Angle's Class I key is that the mesiobuccal cusp of the maxillary first molar occludes in the buccal groove of the mandibular first molar.

Which type of joint movement occurs at the temporomandibular joint during wide opening of the mouth?

Answer: Both rotation and translation

During wide opening, the TMJ first rotates (hinge movement) and then translates (condyle moves forward and downward along the articular eminence).