Week 10 - Mouth Preparation Flashcards
(21 cards)
How should rests be prepped
o Create rounded otherwise it will not allow some movement in function, saucer-shaped floors sloped toward the tooth core.
o If the clasp extends buccally from an occlusal rest the prep must be extended as a channel on the buccal surface (may need to recontour the cusp of the opposing tooth
o May require cusp reduction or buccal extension. – requires an adequate bulk of material linking the occlusal rest to the minor connector
o Check room for 1 mm metal thickness.
o Use pink wax bite test to assess clearance
- may require beveling for cingulum rests
What are guide planes
Parallel axial surfaces on abutment teeth.
what is the function of guide planes
o Enhance stability and reciprocation.
o Limit path of insertion of a denture
o Prevent clasp deformation.
o Improve aesthetics via intimate contact between denture and tooth.
What is * CSP – Channel, Shoulder, Pin system (Steigerand & Boitel, 1959):
A special attachment
o Intra-coronal attachment for bracing and support
o Offers vertical support and guide planes.
o Requires precision milling or CAD-CAM.
o Depth and taper are crucial.
What is a semi-precision rest
- Pre-fabricated rest elements needing exact preparation
- Offers precision without full custom milling
What are denture considerations for exostosis and tori
- Dentures designed to avoid or span over them.
- May require surgical removal if interfering with denture seating.
What is hyperplastic tissue
Overgrowth of soft tissue
What causes hyperplastic tissue
Chronic irritation from ill-fitting dentures.
What are problems with hyperplastic tissue and dentures
o Affects denture fit, stability, comfort.
o Risks long-term complications. –> inflammation or infection
How to manage hyperplastic tissue
o Conservative (tissue conditioner) adjusting ore relining the existing denture to reduce inflammation
o Surgical removal of the hyperplastic tissue
o Healing period required before new denture.
What are stock trays
- Pre-made, general fit.- comes in a standard size
- Suitable for primary impressions. – good for quick initial impressions
- Less precise
- Can be metal or plastic; dentate or edentulous designs.
What are custom trays
- Made for one patient using preliminary impressions.
- Patient specific
- Advantages:
o More accurate for final impressions.
o Allows spacing and adaptation. - Use adhesive or holes depending on impression material.
What is border molding
- Involves shaping the borders of a custom impression tray to accurately reflect the peripheral extent of the denture by engaging the movable soft tissues surrounding the denture space
- Customizes tray borders to reflect soft tissue anatomy.
- Enhances stability and retention of denture.
- Materials: Thermoplastic (green stick) or rubber-based.
- Must not encroach into tray space. tray should be 2mm short of the deepest part of the sulcus and material is added to edges only
What is a spaced tray
tray with space between the tray and the teeth
What material is used for spaced trays
alginate or regular body elastic impression materials
What is a close fit tray
were the tray closely adapts to the surface of the cast leaving minimal or no space between the tray and tissue
What material is used for close fit trays
Metal oxide (ZOE) and light body elastic impression materials
What is flabby ridge
Mobile, fibrous soft tissue of the edentulous alveolar ridge often in anterior maxilla. Consist of hyperplastic soft tissue that replaces resorbed bone lacking the firm support needed for prosthesis stability
- Results from prolonged denture use of uneven occlusal forces causing bone resorption and tissue overgrowth
- Occurs in maxillary region when opposing natural mandibular anterior teeth
What are problems with flabby ridge
Easily compressed, affecting denture stability. poor stability
What are custom tray modifications for flabby ridge
o Indicate ridge on model for the lab
o Provide relief spacing and pressure relief channels.
o Results in a close fitting tray with a spaced anterior ridge – a channel or holes are used as a pressure relief valve to prevent compressing the flabby ridge
What is impression technique for flabby ridge
o Use light-body material (ZOE or PVS).
o Avoid tissue compression by injecting material or using a window technique.
