Partials Flashcards
Which classification can you not have a modification?
4
What classification can we use for edentouls spans ?
Kennedy
1: bilateral free end
2. Unilateral free end
3. Bounded saddle
4. Anterior bounded that Cross the midline
What are the problems with Kennedy class 1?
Tooth and mucosa bourne and thus always gonna get differential movement due to varying compressibility of tissues
Needs max coverage of tissues to gain wide support and indirect rotation to minimise rotation
Kennedy class 3 is always what kind of support?
Tooth
Unless really long spans or decreases perio
What is a classification for support?
Craddock
Tooth
Tooth and mucosa
Mucosa
What is support?
The resistance to vertical forces towards to the mucosa
What are the advantages of tooth support?
Forces directed throu pdl If designed correctly no damage to teeth Well tolerated Good support Retention Bracing
But: harder to design and construct, technique sensitive, harder to adjust, more expensive
What are the advantages and disadvantages of mucosal borne?
AD: Cheap Can be added Good for perio Young children Easy to adjust Easy to repair
Dis: soft tissue support, lacks retention, potential for damage due to compressibility of tissue, gum stripper
What happens if excessive forces are transmitted to the tooth?
Bone resorption and mobility of teeth
What three things do you need to consider when planning support?
- Root area of abutment teeth
- Saddle extension
- Force expected on saddles
What is the major connection?
Primary function: Joins all the saddles to the denture
- provide retention via indirect retention, contact guide planes,
- It rests or covers alveolar ridge , and carries the teeth,
- support and bracing
- stress disturbuton across all abutments
WHat is the purpose of minor connectors?
Joins the components such as the rests, clasps to the major connector
What is rentemtion?
Ability to resist forces away from the tissue
What is bracing?
The ability of the denture to resist lateral forces
What is the order for design of a partial denture?
Kennedy class Saddles Support Retention Reciprocation Indirect retention Major connector Minor connector
Where does a mucosal borne denture get its support from?
Entirely from the soft tissue
What materials can mucosal borne dentures be made from?
Acrylic Cobalt chrome Vinyl resin Titanium Gold Stainless steel Polycarbonate Nylon Vulcanite
What are the design features of a mucosa Bourne dentures?
Wide support
Polished surfaces in neutral zone
Avoid clasps where possible on mucosa borne
What are the principle for every dentures?
Wide support
Ginivlly free
Dental arch restored via Point contact to aid retention, protect gingiva, limit tooth movement, reduce stagnation area
Flange maintains anterior post stability
Distal stop to maintain arch integrity
Free inn occlusion
How effective are lower mucosal support dentures?
NOT!
They are gum strippers since the lingual bar will dig into the lingual mucosa and the lingual plate would cause plaque to accumulate and cause gingival damage
What are the three exceptions to lower mucosal support?
Temporary
Transitional
Replacing success
How can you aid retention of mucosal Bourne?
Embers sure hooks
Adams clasp
Wrought clasps
What can wrought clasps be made from?
Stainless steel
Gold
Wrought CoCr (wiptam)
Acetylresin
What component on the denture will provide retention?
Clasps that engage in undercuts. They are flexible
What are the two types of clasps?
Occlusally approaching and gingival approaching
Which part of the occlusal approaching clasp arm should engage in the undrcut?
The terminal third
Which part of the ginivally approaching clasp should touch the tooth?
Only the tip
What materials can claps be made from?
CoCr cast or wrough
Stainless steel
Gold wrought
Acetyl resin
What factors will affect the flexibility of the clasp?
Material Length Cross section Curvature Thickness
What are the factors which will dictate the clasp of choice?
- Position of undrcut
- Amount of bone support
- Length of clasp
- Appearnce
What are the features of a major connector?
Rigid Comfort Well tolerated Ideally be ginivally free Unobtrusive
What are the major connectiors in upper arch?
Ring: multiple bounded saddles Horse shoe Palatal strap Palatal bar Complete palate
What will the choice of major connector depend upon?
Function Anatomy Hygiene Rigidity Patient acceptably
What are the advantage and dis of a horse shoe?
AD: strong and useful for anterior missing teeh, relieves the palate, gains some tissue support
Dis: can distort in free end saddles, some patients dint like bulk of metal Anteriorly
What are the advantage and dis of a Palatal strap?
AD: thin and versatile, can be in two planes to increase rigidity, well tolerated, good tissue supper due to increase SA
Dis: must be at least 8mm In width for for strength, oateint may not like strap over rugae and junction of hard and soft palate
What are the dis of Palatal bar?
Bulky
Narrow so little support
If anterior to second premolars may impede on speech
What are the ad and dis of complete Palatal cover?
Best rigidit
Most comfortable
But extensive coverage on tissues and OH and denture hygiene issue
What are the issues with maxillary connectors?
- Borders must be at least 3mm from gingiva or extended on to tooth
- borders should blend with anatomy
- thickness of metal should be uniform
- all borders in contact with soft tissues should be beaded
WHat type of connector should you use for upper anterior teeth that nee to be replaced?
Complete plate
Horseshoe
Ring
What should you use for a palatine torus?
Horseshoe or ring
What are the designs for the lower jaw?
Sublingula bar Lingual bar Dental Kennedy Lingual plate Labial bar
When would you use a sublingual bar?
In people where lingual bar cannot be used
It’s dimensions are determined by a specialised master impression that represents the functional depth and width of the sulcus. Technician needs to wax up the shape according to this. This means the maximum cross section dimemstoo is horizontal.
What is the lingual bar?
Bar placed lingually a minimum of 3mm from gingiva
Most commonly used
Need to relief the bar with a 30 gauge wax in cases of free end saddle to prevent tissue impingement
What is the cross section of a lingual bar?
Pear
What is the occlusal gingival width of a lingual bar?
7mm
Where should the lingual bar be placed?
As low as the depth of the sulcus will allow
What is a lingual plate?
Lingual bar plus extension onto teeth
Used when cannot use a lingual bar and also possibly to splint lower teeth when perio is stable
Not good for diastemas unless notch out the metal
Promotes plaque
Caries
What is a dental bar? And when is it use ?
This is used when there is no space for a sublingual or lingual bar and placed only on to the teeth
Good for long clinical crowns
Not tolerated well
What is a kennedy bar?
Continuous clasp
Lingual bar plus Sedondary bar over the clingulum of teeth
Not well tolerated and difficult to make
Debris trapped
Crowded teeth difficult to use with
Excellent indirect retention
What is a labial bar?
This is placed labially for inclined teeth
Aesthetics an issue and bulky under lip and needs sufficient sulcus depth
What design should we use for tooth supported in lower arch?
Lingual bar
What should we use of space in the lower arch is insufficient for a lingual bar?
Lingual plate
When does bracing occur?
Resistance to horizontal forces when the denture is fully seated
When does reciprocation occur?
Resistance to lateral forces when the denture moves from fully seated to over the maximum bulbosity of the tooth
Which part of the clasp does the bracing?
The rigid 2/3
Bracing on teeth occurs from what?
Rigid portion of clasp arm or plates
Bracing on ridges occurs from what?
Major connectors and flanges
How do every dentures achieve retention?
Frciton
Adhesion
Cohesion
What denture material can touch the mucosa?
Acrylic or metal
For a CoCr denture what can you do to enable acrylic to be along fit surface?
Acrylic is attached to metal work via a spaced meshwork sometimes a stop of metal can be included which contacts the cast
What is the advantage of the impression surface being metal?
More space is allowed for teeth which is good when there has been over eruption of oppsing teeth
When is it ideal to have acrylic as the impression surface?
When more resorption is likely to occur and also can easily be added to eg distal extension
What can the junction between the denture and abutment be?
Open or closed
Closed means can utilise the distal of the tooth as a guide plane
What Type of rest is placed in molars and premolars?
Occlusal
Wat type of rest is placed on canines?
Clingulum
What time of rest is placed on mandibular canines?
Incisal
What are the functions of rest seats?
Distribute forces Maintain components in correct position Protected denture abutment tooth junction Provide indirect retention Provide reciprocation Prevent over eruption Improve occlusal contact
How are partials retained?
Mechanically eg clasps engaging in undercuts
Muscular control
Physical forces
What is indexing?
This is when you mark the master cast to enable you to remount back onto the articulators
Can groove or notch
