Dental Anatomy & Occlusion Flashcards

How many cusps does a maxillary first molar typically have?

Answer: 4 cusps (with a 5th Cusp of Carabelli occasionally)

The maxillary first molar has 4 main cusps: mesiobuccal, distobuccal, mesiopalatal (largest), and distopalatal. The Cusp of Carabelli is an accessory cusp on the mesiopalatal cusp, present in about 60% of individuals.

What is the angle formed between the occlusal plane and the condylar guidance path called?

Answer: The Fischer angle (or Bennett angle — actually these differ; the angle between condylar path and occlusal plane is the Balkwill angle)

The Balkwill angle (approximately 26°) is formed between the occlusal plane and the path of the condyle. The Bennett angle is the angle formed by the working side condyle moving laterally.

What is Angle's Class II Division 2 malocclusion characterised by?

Answer: Retrognathic mandible, upper central incisors retroclined, deep overbite, and increased overjet that may be masked by retroclination

Angle Class II Div 2 features a distal molar relationship, retroclined upper central incisors (distinguishing it from Div 1), upper lateral incisors often proclined, and typically a deep overbite with reduced overjet.

Which permanent tooth has the longest root?

Answer: Maxillary canine

The maxillary canine has the longest root of all permanent teeth, making it very stable in the arch and explaining why it is typically the last anterior tooth extracted when arch preservation is needed.

In the primary dentition, which tooth does NOT have a permanent successor?

Answer: Primary second molar (replaced by a permanent premolar)

All primary teeth are replaced by permanent successors: primary incisors and canines by permanent incisors and canines; primary molars are replaced by premolars (not permanent molars).

What is the term for the physiological resting position of the mandible?

Answer: Postural rest position (mandibular rest position)

The postural rest position is when the mandible is at its physiological rest, with the lips lightly together and the dentition slightly apart (freeway space of 2–4 mm). It is a neurologically determined position.