INBDE Prosthodontics and Occlusion 1 — Questions and Answers
Question 1: Centric relation (CR) is best defined as:
- The position of maximum intercuspation of the teeth
- The most retruded position of the mandible
- The most superior, anterior position of the condyles in the glenoid fossae (Correct answer)
- The habitual closure position of the mandible
Correct answer: The most superior, anterior position of the condyles in the glenoid fossae
Centric relation is the maxillomandibular relationship in which the condyles are in their most superior (and slightly anterior) position in the glenoid fossae, independent of tooth contact.
Question 2: Canine-protected occlusion refers to:
- The canines bearing all lateral excursive contacts while posterior teeth disclude (Correct answer)
- Equal distribution of forces on all teeth in lateral excursion
- Group function on both working and balancing sides
- Immediate posterior disclusion via the anterior teeth
Correct answer: The canines bearing all lateral excursive contacts while posterior teeth disclude
In canine-protected (mutually protected) occlusion, the canines bear and guide all lateral excursive forces, allowing the posterior teeth to disclude and be protected from lateral forces.
Question 3: The Bonwill triangle in prosthodontics represents:
- The relationship between condyles and the incisors forming an equilateral triangle (Correct answer)
- The path of condylar movement in protrusion
- The angle of the eminence to the Frankfurt horizontal
- The cusp height formula for posterior teeth
Correct answer: The relationship between condyles and the incisors forming an equilateral triangle
Bonwill's triangle is an equilateral triangle with 4-inch sides connecting the two condyles and the mesial contact point of the mandibular central incisors.
Question 4: A facebow transfer records the relationship of:
- Upper teeth to lower teeth in centric occlusion
- Maxillary arch to the transverse hinge axis of the condyles (Correct answer)
- Mandible to the Frankfurt horizontal plane
- Vertical dimension of occlusion to rest position
Correct answer: Maxillary arch to the transverse hinge axis of the condyles
A facebow records the spatial relationship of the maxillary arch to the opening axis of the condyles (transverse hinge axis), allowing accurate mounting on an articulator.
Question 5: The closest speaking space refers to:
- Freeway space (interocclusal distance)
- The closest vertical relationship of upper and lower teeth during speech (Correct answer)
- The distance between the lips at rest
- Occlusal vertical dimension
Correct answer: The closest vertical relationship of upper and lower teeth during speech
The closest speaking space (1–2 mm) is the minimum distance between maxillary and mandibular teeth observed during phonation of sibilant sounds like 's'.
Question 6: Residual ridge resorption after tooth extraction follows a pattern that is:
- Equal in maxilla and mandible
- Greater in the maxilla vertically, greater in the mandible horizontally
- Greater in the mandible in all dimensions (Correct answer)
- Ceases after 6 months post-extraction
Correct answer: Greater in the mandible in all dimensions
The mandibular ridge typically resorbs 4 times faster than the maxilla overall, and resorption is greater in all dimensions in the mandible, making mandibular dentures more challenging.
INBDE Prosthodontics and Occlusion 1
Centric relation (CR) is best defined as: