Occlusal rims Flashcards
(15 cards)
What is the primary purpose of a dental occlusal rim?
To establish the vertical dimension of occlusion, record the centric relation of the jaws, and provide support for the lips and cheeks during the fabrication of complete dentures.
What material is commonly used to fabricate occlusal rims?
Baseplate and wax.
What is vertical dimension of occlusion (VDO)?
The distance between a selected point on the maxilla and a selected point on the mandible when the teeth are in maximum intercuspation (or the occlusal rims are in contact).
What is centric relation (CR)?
A maxillomandibular relationship in which the condyles articulate in the anterosuperior position against the slopes of the articular eminences. It is a purely rotary movement about the transverse horizontal axis.
How should the maxillary occlusal rim typically relate to the upper lip at rest?
It should support the upper lip to its natural contour and display approximately 1-2 mm of the wax below the lip line.
What is the Camper’s plane, and why is it important when adjusting the maxillary occlusal rim?
Camper’s plane is an imaginary plane extending from the ala of the nose to the tragus of the ear. The occlusal plane of the maxillary rim should ideally be parallel to Camper’s plane to achieve a balanced and esthetic denture.
What is the Fox plane, and how is it used with occlusal rims?
The Fox plane is an instrument used to check the parallelism of the occlusal plane of the maxillary rim with Camper’s plane and the interpupillary line.
How is the mandibular occlusal rim typically contoured in the posterior region?
It is usually contoured to follow the retromolar pads and be slightly lower than the maxillary rim in the posterior to allow for the recording of centric relation.
What information is often recorded on the occlusal rims during the jaw relation appointment?
The midline, canine lines, high lip line, and sometimes the smile line.
What is the significance of the ‘s’ sound when evaluating the vertical dimension with occlusal rims?
During the ‘s’ sound, the front and back teeth (or occlusal rims) should come into close proximity but not touch.
If whistling sound = unimpeded airflow = palatal rugae area too high or narrow. Tx by adding resin to rugae area.
If lisps = airflow excessively impeded. Tx by reducing resin contour at rugae area.
What is the purpose of notches or indentations sometimes placed on the occlusal rims?
To provide a positive interlock for material used to register centric relation (ie. bite registration).
It records the relationship between the maxillary and mandibular arches at a specific vertical and horizontal jaw relation (often centric relation) for casts to be accurately mounted on an articulator.
What might happen if the vertical dimension established with the occlusal rims is too great?
It can lead to clicking of teeth, muscle fatigue, difficulty swallowing, and an unnatural facial appearance.
What might happen if the vertical dimension established with the occlusal rims is insufficient?
It can result in a collapsed facial appearance, angular cheilitis from saliva pooling, reduced masticatory efficiency, and potential temporomandibular joint issues.
Phonetics - significance of “f” sounds?
Dry line of lower lip should contact incisal edges of maxillary occlusal rim.
Determines location and length of maxillary teeth.
How to guide PT into centric relation?
Bimanual manipulation - stand behind PT, fingertips on inferior border of mandible, thumbs on chin, move mandible superiorly and posteriorly in an arc-like movement into centric relation.
Tongue to palate - PT to curl tongue tip as far back on palate as possible and slowly close together into centric relation.
