prosthodontics Flashcards
what is the vibrating line?
junction between the hard palate and soft palate
what is the occlusal plane?
horizontal surface occupied by upper teeth
extends from tip of mesioincisal edge of upper central incisor to of mesiobuccal cusp of upper 1st molar on each side
what is the neutral zone?
specific area where the function of musculature will not unseat the denture
where forces generated by tongue are neutralised by forces generated by lips and cheeks
how is denture stability achieved?
make sure peripheries of denture are extended to the right depth
by making sure occlusion is balanced
what is the occlusal rim?
a wax structure with occluding surfaces attached to denture base
what is an occlusal rim used for?
recording relation of maxilla to mandible
positioning of the teeth
what features should be present on maxillary definitive impressions?
tuberosity
hamular notch
extension anterior to vibrating line for post dam
functional depth and width of sulcus
what features should be present on a mandibular definitive impression?
coverage of pear-shaped pad and buccal shelf
retro-molar pad and extension into lingual pouch
functional width and depth of sulcus
ensure area of primary support of buccal shelf and retromolar pad
where should a maxillary denture sit in order to create a good posterior seal?
at level of hamular notch
located between distal surface of tuberosity and hamular process of medial pterygoid plate of maxilla
describe use of impression compound for primary impressions
non-elastic material which records poorer surface detail
expensive and can be messy
good for primary due to high mucocompressive viscosity
describe the use of alginate for primary impressions
elastic material- will flow into undercuts
can record surface detail for primarys
describe the use of silicone for master impressions
dimensionally stable
can be made into a variety of consistencies which means it accurately records surface detail
describe the use of polyether/impregum for master impressions
dimensionally stable
can be made into variety of consistencies which means it accurately records surface detail
describe the use of alginate for master impressions
elastic- can flow into undercuts if they are present
what is the purpose of stops to the space prescribed in the canine and post dam regions of upper trays?
to allow correction of posterior borders of trays and will perform space for impression material
where should stops be placed to the space provided on lower trays in order to allow preformed space for impression material?
retromolar pad
ridge of canine areas
why is silicone not used for primary inpressions?
dimensionally stable and hydrophobic- can cause small defects and blows
very messy and technique sensitive
what information should be recorded on to a record block?
the OVD
centre line
occlusal plane
high lip line
canine line
arch form
what provides accurate fit for dentures?
accurate fit- as little space as possible between denture base and mucosa
border seal- extending flanges to depth of functional sulcus and incorporation of post dam
what anatomical features help identify where the posterior border should be placed for the upper denture?
hamular notch
vibrating line
palatine fovea
explain the cawood and howell classification
1- before extraction
2- after extraction
3- high well rounded ridge
4- knife edge shaped ridge
5- low well rounded ridge
6- depression bone level
what is the primary support area for maxillary dentures?
hard palate