Removable Pros Flashcards
(150 cards)
1
Q
What are the 4 main types of Rests?
A
- Occlusal
- Cingulum
- Incisal
- Ring
2
Q
What equipment is necessary in Occlusal Rim stage of denture construction? (8)
A
- Occlusal Rims
- Occlusal plane trimmer
- Air heater (for wax) and instrument heater
- Wax knife
- Pink wax - wax additions (e.g. buccally/labially)
- Willis gauge (or Callipers)
- Foxes bite plane
- Bite reg material (Futar D)
- Facebow (not often needed)
3
Q
How do we decide where to place denture rests? (4 points)
A
- Adjacent to saddle (usually)
- Where periodontal attachment of tooth strong enough
- Ideally distributed on 4 teeth spread over arch
- Where occlusal space is available (minimal tooth prep)
4
Q
What are the advantages (3) and disadvantages (2) of making a copy denture vs. new denture?
A
ADVANTAGES:
- No period of time when Px is without dentures
- Less clinic time
- Less time for adjustment (Px used to polished surface)
DISADVANTAGES:
- More lab time
- May be more expensive
5
Q
What is the difference between relining and rebasing?
What material is most often used?
A
RELINE = Addition of material onto denture fit surface to improve overall fit
REBASE = Removal and then subsequant replacement of material onto the fit and polished surface of denture
Material = RT/Self-cure PMMA
6
Q
What are 3 disadvantages of Acrylic (mucosa supported) vs. Cobalt Chrome (tooth supported) dentures?
A
- Less support (difficult to gain tooth support )
- More susceptible to brittle fracture
- More bulky
- Less hygienic design - Gingival margins more often covered (plaque retentive)
7
Q
How much relief should be provided at the gingival margin?
A
3mm
8
Q
What is the ideal:
- Occlusal surface?
- Fit surface?
A
- Even contacts around arch and minimal interference on lateral excurtion with FWS 2-4mm
- Supports soft tissues but not over bulky so that intereferes with muscle activity
9
Q
What happens if there is poor stability in the: 1. Upper denture? 2. Lower denture?
A
BOTH = Denture moves on function
10
Q
What is meant by a denture Rebase?
What are 2 advantages to it?
A
Removal and then subsequant replacement of material (RT Cure PMMA) onto the fit and polished surface of denture
- Doesnt increase palate thickness (unlike Reline)
- Benefit of previous denture base removal (e.g. cases of bleaching)
11
Q
What is Piezography? Outline the steps (3) in carrying out
A
The FUNCTIONAL impression method of recording the DENTURE SPACE
- Place upper denture in mouth
- Apply “Viscogel” onto lower denture and seat in mouth
- Get Px to sip and swallow water to mould Viscogel
12
Q
What are 4 oral landmarks you’d see on a good mandibular impression?
A
- Retromolar pads
- Mylohyoid groove & flange
- Residual alveolar ridge
- Labial frenulum & sulci
13
Q
In what 3 ways can you check SUPPORT on a denture?
A
- Press down on BOTH sides of occlusal surface → See if any movement
- Check how much area covered (and firmness)
- Check for signs of trauma → may need to extend coverage
14
Q
What are the 4 types of RPDs when classifying by “supporting tissue” ?
A
- Mucosa supported - Acrylic
- Tooth supported - CC
- Mucosa and Tooth Combination
- Implant Supported
15
Q
What are 6 indications for REMOVABLE denture over fixed?
A
- Lengthy edentulous span (vs. small where fixed can be used)
- No posterior abutment (Class I or II)
- Cost - Cheaper
- Lack of tooth support (e.g. period)
- Immediate denture
- Anticipated change in denture design
16
Q
What are 4 possible problems with Reline/base of a denture?
A
- Increase in OVD (via increased thickness) - Use thin wash
- Occlusal errors - Use closed mouth technique
- Damage to denture during lab processing (esp. if heat cure PMMA used)
- Irreversible changes to denture (warn Px)
17
Q
What are some causes of denture fracture? (6)
A
- Flexural fatigue (worn over long time)
- Impact fracture from being dropped! (usually mid-line fracture)
- Alveolar resoption under denture - No reline/rebase
- Previous denture repairs → Weakening
- Permanent soft lining in lower → Reduced thickness of hard acrylic
- Abrasive denture cleaning → hard acrylic thinning
18
Q
What is meant by Shortened Dental Arch (SDA)?
A
SDA = Minimum of 4 occluding units remaining in the mouth May be acceptable alternative to dentures (cheaper) following concept this is acceptable for human function
Must have at least 20 teeth present
19
Q
In Occlusal Rim stage of denture construction, how do we set ______ with reference to Px anatomy?
- Height of OCCLUSAL PLANE? (3)
- Anterio-posterior orientation of occlusal plane?
- Lip support? (2)
- Overall OCCLUSAL Vertical HEIGHT? (1)
A
- Use lip line - 17-21mm below Anterior Nasal Spine - Parallel to inter-pupillary line (between R/L pupils)
- Parallel with ala-tragal line
- Naso-labial angle (ideal = 90º) - 8-10mm policed surface thickness between Incisive papilla and outer labial denture surface (N.B. Arch thickness set with Palatal Gingival Remnant: 10mm between PGR and outer buccal surface of denture polished surface)
- Freeway space (2-4mm)
N.B. Also check swallowing and speech
20
Q
What are 3 requirements of an occlusal rim?
A
- Rigid (therefore HC acrylic base preferred over reinforced wax)
- Stable (close adaptation to abutment teeth)
- Well tolerated (correct extension)
21
Q
What post-denture fit instruction should be given? (7)
A
- Shown how to place/remove dentures (get Px to demonstrate)
- Written instruction sheet (Medical Devices Directive)
- Cleaning: Soap and water over sink
- Leave denture out at night (in water)
- Eating - soft food in smaller pieces
- Speaking takes time to get used to
- Review in 1 week
22
Q
What are 3 advantages of Acrylic (mucosa supported) vs. Cobalt Chrome (tooth supported) dentures?
A
- Cheaper
- Quicker (fewer construction stages)
- Easier to make modifications too (e.g. Transitional denture)
23
Q
Explain “SSRSSR” pneumonic for Systematic Denture Design…
A
Saddle - needed?
Support - saddle abutments and rests
Retention - clasps
Strength/rigidity - major connector type
Stability
Review
24
Q
What are 3 circumstances of Acrylic (mucosa supported) denture indication?
A
- Immediate tooth replacement
- Larger saddle areas (reduced tooth support)
- Poor prognosis of remaining teeth - little support
- As a Provisional/Diagnostic Appliance (test px tolerance of increased OVD)
25
Why might denture fit well in all stages up to FPF and then not fit after? (2)
1. Master cast wasn't used as fit surface on FPF 2. Acrylic wasn't extended to full depth of wax contours
26
What does the gingival remnant of an edentulous patient tell us?
Where the patients previous teeth were
27
What is the primary stress bearing area (for dentures) within the mouth?
The residual alveolar ridge (portion of alveolar ridge and soft tissue covering remaining after tooth loss)
28
What are the 3 main functions of Denture Cleansers?
1. Remove food debris
2. Prevent unpleasant odours/tastes
3. Prevent infection *(e.g. denture stomatitis or angular cheilitis)*
29
What are 4 types of MANDIBULAR Major connectors? Which is 1st line?
1. Lingual Bar - 1st line
2. Dental Bar
3. Lingual Plate
4. Buccal/ Labial Bar
30
Outline the treatment sequence in toothwear management with removable pros...
**ASSESS PX**
* Tooth restorability
* Vertical dimention (Normal or Increased FWS)
* Occlusion - stable?
**STABILISATION** - Caries/perio
**PLANNING**
* Articulated study casts
* Diagnostic wax ups if planning fixed restorations
**PROVISIONAL PROSTHESES & TOOTH PREP**
* Provisional denture
* Composite build ups, crowns etc
**DEFINATIVE PROSTHESES**
* Tooth build up & conventional denture
* Onlay, Overlay or Overdenture
**MAINTENANCE**
* Failure - Bruxism or Lack of interdental space!
31
What is a Fulcrum?
An imaginary line around which a denture tends to rotate
32
What point in FPF might case a denture tooth to "debond"?
If thin film of wax is left on teeth during "boiling out stage" of flasking
*Repaired in lab with cold-cure acrylic*
33
In Overdentures, what is meant by "metal copings" and what treatment needs to be carried out prior to their placement?
Metal copings added to protect natural remaining roots from fracture
Endodontic Tx (RCT) must be carried out on root before hand
34
How can impression materials be classified based on setting reaction? (4)
1. Polymerisation/Cross-Linkage *- Addition/Condensation Silicones, Polyether, Polysulphide*
2. Thermoplastic - *Agar, Impression Compound*
3. Gelation - *Agar, Alginate*
4. Chelation *- Alginate, ZOE*
35
What are some potential harmful effects of RPDs? (4)
* Alveolar bone resorption
* Enamel decalcification/caries
* Periodontal inflammation
* Denture stomatitis
N.B. All caused by bad OH, rather than denture itself
36
What are 7 features in the mouth/on denture design that keep the dentures in place?
1. "Peripheral seal" - Saliva suction effect around denture, particularly on Post -dam
2. Muscles (act on polished surface of dentures)
3. Reseating of upper and lower when correct occlusion articulated
4. Gravity - lowers
5. DIRECT retention (Clasps)
6. INDIRECT retention (Rests)
7. Firm soft tissue support (vs. flabby ridges)
37
What are 4 contra-indications for the use of Overlay denture/Overdentures?
* Poor OH
* Uncontrolled caries or peridontal disease
* Inadequate inter-arch space
38
What are the 9 main stages of denture design?
1. Assessment
2. Stabilisation !! - XLA, restore, stabilise perio, OHI
3. Primary Impression
4. Secondary Impression
5. Bite registration
6. Tooth Try-In
7. Denture Design
8. Denture Fit
9. Review
39
What impression materials are used for primary and secondary impressions for:
1. Partial Denture? (dentate)
2. Complete Denture? (edentulous)
1. Primary = Alginate (or Putty washed with Alginate), Secondary = Elastomer (Addition Silicone)
2. Primary = Impression Compound (or Impression Compound washed with Alginate), Secondary = Zinc Oxide Eugenol
40
What is the main difference between Onlay and Overlay Dentures?
Onlay dentures only cover the occlusal and palatally-occluding surfaces of natural teeth
Overlay dentures (or Overdentures) cover the entire natural tooth, extending from occlusal surface to gingival margins. May also utilise remaining roots or implant retention.
41
What is the function of a Facebow record? What are the 3 main reference points?
Relates the upper jaw to hinge axis for greater accuracy in adjusting vertical height 1. Maxilla (taken with bite fork) 2. TMJ (referenced with ear bow) 3. Nation indicator (midline, where nasal and frontal bone meet)
42
Explain "SSRSSR" pneumonic for Systematic Denture Design...
Saddle Support Retention Strength/rigidity - major connector type Stability Review
43
What are the 3 main types of Clasps?
1. Occlusally Approaching (circumferential) 2. Gingivally Approaching 3. Ring (circumferential)
44
What is the ideal articulation in RPD's?
What is this called if it exists in a patients natural teeth?
BALANCED ARTICULATION
Teeth on both working AND non-working side contact on lateral movements →Stable Denture
If exists on natural Px = "Non-working side interference"
45
How can the retention of an Overdenture be improved, aside from clasps, saddle extention and indirect retentive measures?
Precision or Semi-precision attachments encorperated into retained natural roots
(8mm vertical space required)
46
What is the definition of: 1. Kennedy Class I? 2. Kennedy Class II? 3. Kennedy Class III? 4. Kennedy Class IV?
1. Bilateral edentulous area located posterior to remaining teeth 2. Unilateral edentulous area located posterior to remaining teeth 3. Unilateral edentulous area with natural teeth remaining anterior AND posteriorly 4. Single bounded (bilateral) edentulous area crossing the midline located anterior to remaining natural teeth
47
What are 2 disadvantages of Immediate Dentures?
1. Post XLA complications 2. Loss of fit with time (XLA leads to bone loss) so further appointments may be necessary to reline/rebase
48
If only ONE central incisor is missing, what Kennedy classification is this?
Kennedy Class III (NOT 4 as doesn't cross the midline)
49
How does a rest enhance claps function by providing indirect retention (explain with reference to dislodging forces and fulcrum)? Are they more effective when closer together or further away?
[Denture rotates around fulcrum through clasp tips when dislodging force placed on Saddle of Kennedy Class I, II or IV] Addition of anterior rest (on Kennedy class I/II) moves fulcrum forward in mouth (new fulcrum point) Now, when denture begins to rotate upon dislodging force... the clasp tip engages undercut to resist movement
50
What possible problems can arise with the Polished surface of a denture? (4)
* Lingual undercuts on lower denture → Lifting of denture during function (by tongue)
* NO buccal overjet between upper and lower → Cheek biting
* Coronoid process tipping side of flange on upper complete denture → Side to side movement and pain on these lateral exurtions *- Seen by pressure paste application wiping off on this area*
* Heel contacts → Restricted movement *(must be removed)*
51
Overlay denture and Overdenture are often used interchangably, how can you distinguish the two?
**Overlay Denture =** Denture covers occlusal surface of natural teeth to gingival margin
**Overdenture =** Denture covering natural root surfaces (+/- metal copings) and flange extends below the gingival margin
*N.B. May also be implant-retained*
52
What are the 2 clinical and 2 lab stages in making a modified copy denture with the Metal Flask (Murray/Wolland) Technique?
1ST CLINICAL:
* Make denture modifications
* Add 2 pieces of stiff rolled wax (or greenstick) to denture heels
* Fill 1st flask with alginate, insert denture (occlusal/polished surface down) and set
* Cover denture surface with petroleum jelly (separating agent)
* Fill 2nd flask with alginate - close and set
* Remove denture and greenstick
Denture moulds → Lab
Denture → Px (shade match needed)
1ST LABS:
* Moulds: Wax poured to teeth and denture base poured as RT/Cold-Cure acrylic
* Each wax tooth removed and replaced with denture tooth
2ND CLINIC:
* Tooth try-in
* Take CLOSED MOUTH IMPRESSIONS with both dentures in light bodied silicone (RELINE)
2ND LAB: FPF
53
What is the difference between a free end and bounded saddle? What kennedy classifications do each relate to?
FREE END = Saddle found posteriorly to remaining teeth (no teeth after) - Kennedy Class 1 & 2 BOUNDED = Saddle found restoring teeth with remaining teeth found anterior & posteriorly - Kennedy Class 3
54
Which impression technque (open or closed mouth) should be used when relining a:
1. Complete denture?
2. Partial denture?
1. Complete = CLOSED MOUTH (in occlusion)
2. Partial = OPEN MOUTH
55
What impression material is best for copy dentures?
Putty (Silicones)
56
What are 3 advantages of Immediate Dentures?
1. Maintain appearance
2. Replicate tooth position - avoids tooth movement
3. Avoids tongue spread
57
How is the impression technique altered for a maxillary anterior fibrous "flabby" ridge?
(HINT: 2 phase, 2 stage)
* Medium-bodied Addition Silicone full arch impression
* "Flabby ridge" area cut out slightly
* Syringe light-bodied silicone onto flabby ridge and re-seat impression
58
What 3 ways can occlusion be checked on denture fit appt?
1. Visually
2. GHM/Shimstocks
3. Ask for Px feedback (e.g. can you feel your own teeth in contact?)
59
What is the alternative to rest seats in tooth preparation for denture rests?
Composite rest seats! Normally for incisal - composite ledge added lingually (Usually done on lower to avoid effecting occlusion)
60
How much relief space should be between a lingual bar and floor of mouth? (What is the other important measurement with reference to lingual bar seating on soft tissues)
At least 7mm (7-8mm ideal) N.B. Should also be 0.5mm relief from tissues (SHOULDN'T directly rest on soft tissues)
61
How can a tooth be added to an existing denture if:
1. Broken off?
2. Missing or recent XLA?
1. Lab repair with cold cure PMMA
2. Impression of denture in situ ("over impression") and opposing arch (if needed) → New tooth added with cold cure PMMA in labs
62
What is the definition of: 1. SUPPORT? 2. RESISTANCE? 3. STABILITY?
1. Resistance of a denture to displacement (movement) in the direction towards underlying tissues (i.e. resistance to occlusal directed loads)
2. Resistance of a denture to displacement away from the DBA in a direction perpendicular to the tissue surface at REST
3. Resistance of a denture to displacement away from the alveolar bone in any direction, during FUNCTION (e.g. eating or speaking)
63
How do you carry out a "closed mouth" impression?
Using dentures or wax occlusal rims
Light-bodied silicone applied to fit surface and seated in Px mouth (UPPER BEFORE LOWER)
Impression taken as patient bites together and border manipulation with swallowing, pouting and grimacing
64
What is the result of a lingual undercut on lower dentures?
Polished lingual surface impinges on "denture space" and alters stability as tongue has tendency to push denture upwards
65
How long after denture fit should a review appointment be made?
What instructions should you give Px if dentures are causing pain?
1 week
Pain: Ask Px to leave dentures out and only put back on day of denture review appt
66
What equiptment is needed for a new denture fit appt? (5)
* Examination kit
* Pros trim bur and handpiece
* "Pressure Paste" (Exctrude or ZOE) *- Check fit, rubbed off in high spots*
* "Occlude Spray" - *Check fit surface of framework*
* Articulating paper and/or Shimstocks (thinner so more precise)
67
What are "flabby ridges"? What do they affect when designing dentures?
Fibrous replacement of alveolar bone Reduce SUPPORT
68
What should you do initially (outside of px mouth) before tooth try in on complete denture px (3)?
1. Try denture occlusion on articulators - including balance on excursive movement 2. Hold dentures together to check stable ICP 3. Disinfect !! (Sodium Hypochlorite)
69
What is the definition of: 1. ICP or "Centric Occlusion"? 2. RCP or "Centric Relation"? In denture bite/jaw registration stage, what are the indications of use for both?
ICP = Occlusal position with maximum contact between upper and lower teeth when Px bites down RCP = A bilateral, unstrained position of the mandible where the condylar disc is in the most anterior and superior position in the glenoid fossa and where pure hinge axis opening can occur for the first 20-25mm of incisal opening THIS IS THE ONLY REPRODUCIBLE BORDER MOVEMENT (1.25mm +/- 1mm) slide between ICP and RCP ICP = "Conformative Approach" where sufficient teeth present allowing stable occlusion RCP = "Reorganised Occlusal Approach" where insufficient teeth causing unstable occlusion
70
Why should we not copy a "successful" upper denture if there are problems in the lower?
How would you address this issue clinically? (4 steps)
Upper denture dictates tooth position of lower denture (posterior teeth set up) - It might be this incorrect set up causing instability (e.g. via lingual undercuts on the Neutral Zone → Tongue lifts up denture)
1. Copy Upper denture BUT replace posterior tooth set up with wax rims
2. Neutral Zone/Piezograph Technique: Take functional impression of lower denture with Viscogel to measure Denture Space
3. Make wax rims for lower
4. Register/Alter OVD with upper and lower
5. Send wax rims to the lab - Neutral Zone should dictate upper and lowe set up
71
Other than frictional contact with remaining teeth and clasps, what are 2 other denture designs to give retention?
1. Sectional Denture - 2 parts with different POIs, inserted separately into mouth and locked together with hinge 2. Precision or Semi-Precision Attachments - usually intra-coronal additions, requiring cast restorations on abutment teeth & relying on frictional contact between machined "male" and "female" parts
72
In what 2 ways can lab errors be avoided at Jaw registration stage? (If not would lead to errors in tooth try-in)
1. Remove heel contacts between U/L casts on articulation 2. Retake interocclusal records with Future D (bite reg)
73
What are the 5 main types of Denture Cleansers?
Which is the main one we recommend?
1. Soap and Water *- RECOMMEND*
2. Denture Paste (Mechanical Cleanser)
3. Alkaline Perioxide Cleanser (Chemical)
4. Dilute Acid Cleanser (Chemical)
5. Alkaline Hypochlorite Cleanser (Chemical)
74
What 6 things should you be checking on tooth try in stage of denture construction?
1. Tooth shade and shape - Matching existing teeth and Px happy
2. Occlusion and OVD (visual assessment & articulating paper use)
3. Support, Retention (inc. wax extension & clasps) and Stability
4. Extension and contouring of wax flanges AND palatal wax extension
5. Size and shape of major connector (ideally = extended to junction between hard and soft palate)
6. Thickness of major connector
75
In Modified Copy Dentures, how do we make changes in cases of:
1. Occlusal Wear?
2. General Wear?
3. Loss of Retention?
1. Add RT/cold-cure acrylic to denture teeth and trim to establish RCP
2. Add RT/cold-cure acrylic to denture borders and post dam (maximise coverage and improve border seal)
3. RELINE - Hard Reliner (RT/Cold-Cure PMMA) or Soft Lining Materal (RT PEMA)
76
What are 7 indications of Removable dentures vs. Fixed?
1. Covers larger spans in mouth
2. No posterior abutment tooth present
3. Lack of tooth support (e.g. Px with periodontitis and mobile teeth)
4. Anticipated future change in denture design (Transitional denture e.g. more teeth to be lost)
5. Immediate replacement - e.g. Interim, after trauma
6. Cheaper
7. Px preference!!
77
What are the 4 main aims of a Provisional Prosthesis (e.g. Michigan Splint)?
1. Increase vertical dimention
2. Assess appearance
3. Assess denture wear tolerance (e.g. speaking and eating)
4. Prevent further toothwear or trauma
78
What is the post-dam of a denture? Where should it be and what are 4 ways you can identify this location on the patient?
Seal/compression that enables the denture to stay in place Position: Junction between hard & soft palate 1) Look for colour change at junction 2) Identify foveae palati (found posteriorly to junction) 3) Palpate with blunt instrument (e.g. flat plastic) 4) Ask Px to say "ahh" & see where vibrating line occurs
79
What are the 4 main components of a denture clasp?
1. (Occlusal) Rest 2. Retentive arm 3. Reciprocating/Bracing arm 4. Minor connector
80
What is meant by a "Conformative Approach"? What is the opposite of this?
RPD formed which harmonises with the patients existing occlusal scheme (In Px with sufficient teeth for stable occlusion, jaw/bite registration stage taken in ICP)
OPPOSITE = Reorganised Occlusal Approach (Taken in RCP, where insufficient teeth for stable occlusion or wear cases)
81
What are 6 medical history points/concerns relevant when choosing denture design for a Px?
1. Physical ability ( e.g. Arthritis or Parkinsons → reduced OH)
2. Visual or hearing issues → Compromised ability to remove plaque or understand OH instruction
3. Attendance with Chronic Illness
4. Airway issues (e.g. Asthma or COPD)
5. Dry mouth - current medications or radiotherapy
6. Spinal issues - chair side
82
What Freeway Space (mm) do we aim for? How is this calculated?
2-4mm RVD - OVD (Resting Vertical Dimension) - (Occlusal Vertical Dimension)
83
What happens if there is poor resistance in the: 1. Upper denture? 2. Lower denture?
1. Drops down
2. Lifts up slightly (Both when mouth at REST)
84
In an edentulous patient, what impression material is used in primary and secondary impressions for complete dentures?
Why are 2 different materials used?
1. Primary = Impression Compound (MUCOCOMPRESSIVE/DISPLASIVE)
2. Secondary = ZOE (MUCOSTATIC)
85
Why might you choose to retain (vs XLA) posterior teeth with poor prognosis in the early stages of denture construction?
To support the occlusion in denture construction phase
86
What is meant by the Path of Insertion? How can it be limited to only one?
POI = Path followed by the first contact of the denture with the abutment teeth until fully seated (usually at right angle to tooth) Limited through GUIDE PLANES (Natural or Artificial) GP = A series of 2 or more parallel surfaces oriented to limit the POI
87
What are "Applegate's" 4 rules applied to Kennedy Classification?
1. Most posterior area determines Kennedy Classification (therefore Class I/II over III/IV) 2. Additional edentulous areas described as "Modifications" (e.g. Kennedy X modification 2 if 2 MORE areas) 3. THERE ARE NO MODIFICATIONS TO CLASS IV 4. Missing 2nd and 3rd molars are discounted if not being replaced
88
In Px with toothwear, what 2 instances might we need to provide a denture?
Following this, what 3 things must we assess?
* Px has missing teeth
* Toothwear so extensive, restoration not feasible
1. Assess restorability
2. Assess vertical height (Normal Freeway Space if TSL accompanied by alveolar compensation or Increased FWS if not → Px overclosing)
3. Stability of occlusion, can Px be guided into RCP if unstable?
89
What care instructions would you give a Px with Denture stomatitis?
* Keep dentures clean and leave out at night!
* ST **Alkaline Hypochlorite** Cleanser soak ("Miltons")
* Topical antifungal use (Miconazole Gel)
* MH Investigation (e.g. systemic deficiencies
* Denture - Ill fit?
90
Which 3 Denture Cleaners have a Chemical MOA?
Which one is used (short-term) for Oral Candidal Infection/Denture Stomatitis?
1. Alkaline Peroxide *("Immersion" type, O2 bubbles produced dislodge debris. Potential harm to temporary soft liners)*
2. Dilute Acid Cleansers *(Softens/dissolves calculus which can then be brushed away. 5% Hydrochloric acid = Most damaging (clothing and corrodes metal) Sulphamic acid = Less damaging*
3. Alkaline Hypochlorite - Used ST as denture soak in Denture stomatitis Tx *(May corrode metal and cause denture bleaching)*
91
What is the DBA?
Denture Bearing Area (Occlusal surface of denture)
92
What are the 7 steps involved in Flask, Pack & Finish? What step (of the 3 names above) is the most susceptible to errors?
1. Place wax tooth try-in on master cast 2. Secure to cast using wax around edge 3. Place try-in on mounted cast into 1st half of a metal flask and space with plaster 4. Fill 2nd half of metal flask with plaster and push 2 halves together till upper and lower metal flasks meet (this is an important reference point!) - remove any excess 5. Open flask (teeth remain set in plaster, wax removed) 6. Replace wax with pink heat cure acrylic into mould (push two halves together till 2 halves meet and leave to HC overnight in hot water bath) 7. Open flask, remove denture by breaking plaster cast & Trim/Polish denture Most susceptible stage for errors = FLASKING
93
Other than in patients with insufficient teeth for stable occlusion, when might RCP be used in jaw/bite registrations as part of the "Reorganised occlusal approach"?
In tooth wear cases! Tooth wear --\> Loss of occlusal height (OVD) --\> We aim to increase this, which will result in loss of natural ICP
94
What are 4 types of MAXILLARY Major connectors? Which is 1st line? (HINT: They all begin with Palatal)
1. Palatal Bar (Anterior, Middle & Superior) - 1st Line 2. Palatal Strap 3. Palatal Plate - use if free end saddles 4. Palatal Horseshoe
95
What information should be written on disinfected lab work before being sent off?
Px name & DOB DISINFECTED: Date Student name
96
In what 2 ways can you check RETENTION on a denture?
1. Hold onto denture teeth and try pull away from underlying tissues
2. Press firmly on incisal edge of anterior → see if back of denture drops
97
At what angle should minor connectors emerge at in reference to the gingival margin
90º
98
What are the 4 types of RPDs when classifying by "use" ?
1. Immediate Partial Denture - Construction and fit in same appt as tooth XLA
2. Transitional Partial Denture - For px about to lose all teeth, teeth added onto denture as lost
3. Diagnostic Appliance - Test increase in OVD or aesthetics
4. Definitive Partial Denture
99
In Copy Dentures, what is meant by a:
1. Replica Denture?
2. Modified Denture?
What is an indication for both?
1. REPLICA = Exact copy of denture (Px wants spare denture)
2. MODIFIED = A copy in which improvements are made to it (For Px with previous successful denture with wear overtime, especially in elderly patients who find it harder to adapt to new dentures/big changes)
100
What are 3 social history points/concerns relevant when choosing denture design for a Px?
1. Living arrangements and attendance
2. Smoking
3. Diet - erosive factors (including alcohol - solvent causing craze formation in PMMA)
101
When should Jaw registration be used? Through correct articulation of master casts, what 3 things does it allow?
Only in Px with NO sufficient occlusal contacts to allow correct articulation of casts 1. Analysis of occlusion 2. Design & construction of denture components 3. Correct teeth setting for chosen occlusion
102
In what 3 ways can you check STABILITY on a denture?
1. Press down on ONE side of occlusal surface → See if opposing side moves
2. Observe denture movement during function (speech)
3. Check Px denture history
103
What are 5 oral landmarks you'd see on a good maxillary impression?
* Lingual frenulum
* Incisive papilla
* Fovaea palatini
* Maxillary Tuberosity
* Hamular Notch
AND (As with the lower): Residual Alveolar Ridge and Sulci
104
When designing polished surface of a denture, what is meant by \_\_\_\_\_, which we must consider... 1. Neutral Zone 2. Denture Space
1. NEUTRAL ZONE = Inward pressure from the cheeks, balanced by outward pressure from the tongue 2. DENTURE SPACE = Space limited by the tongue, lips, cheeks and residual alveolar ridges
105
How can denture fracture risk be minimised through denture _design_? (4)
* Adequate acrylic thickness
* Use of "High-Impact"/"Flexes" Acrylic
* Use of strengtheners (e.g. Selenese fibres or Stainless Steel Mesh embedded into acrylic)
* Incorporation of Cobalt Chrome denture base
106
What 6 aspects of the occlusal rim do you need to set?
1. Height of occlusal plane 2. Anterio-posterior orientation of occlusal plane 3. Lip support 4. Arch thickness/width 5. Arch contour (should be in keeping with contour of residual alveolar ridge) 6. Overall vertical height of U/L rims on meeting
107
What type of acrylic are special trays made from?
Self-Cure/RT Cure/Auto-polymerised
108
What are the 5 major components of a RPD?
1. Saddle - covers edentulous area of arch (N.B. not all edentulous areas are covered with a saddle) 2. Clasps - Direct retention 3. Rests - Indirect retention 4. Major Connectors 5. Minor Connectors
109
What are the 3 denture surfaces ?
1. Fit/Impression Surface
2. Occlusal Surface (Denture Bearing Area)
3. Polished Surface
110
How is the impression technique altered for Mandibular posterior fibrous/"flabby" ridge on Free-End Saddle case?
Impression under "functional" pressure to prevent denture instability on occlusal forces
* Mucostatic Impression taken (light-bodied, ZOE, Impression Plaster) and cast
* Denture metal framework created from above cast on RT cure base
* Denture framework seated in mouth with medium-bodied silicone and no finger pressure
* Impression sent to lab, saddle area removed from previous cast and re-cast with new "functional load" impression
111
What are 3 indications of overdenture/ onlay denture use?
* Converting partially dentate patient to complete dentures
* Toothwear cases
* Hypodontia (congenital tooth absense)
112
What is the difference in location of the Retentive and Reciprocal/Bracing Arms of denture clasps?
RETENTIVE = Terminal 1/3rd of clasp tip sits passively in the undercut (UNDER survey line) and undergoes elastic deformation on denture insertion/removal
RECIPROCAL/BRACING = Stays in contact with the tooth ABOVE the survey line - This prevents horizontal displacement of the denture (Bracing) and the tooth (Reciprocal)
113
What is the main advantage and disadvantage of making denture modifications on the copy denture (rather than making modifications on the existing denture and THEN copying)?
*(N.B. A/D would be swapped for vice versa scenario)*
A: No harm done if changes dont work
D: Don't get to test changes on Px in function before copying
*(N.B. We tend to make modifications on the existing denture before copying - usually any changes made are removable)*
114
What are 5 possible issues following inadequate FPF?
1. Doesn't fit properly 2. Doesn't look good 3. Deterioration of denture surface (proper polish/finish in FPF will not absorb stains) 4. Isn't strong enough (too thin, not fully cured, porosity) 5. Isn't safe in the Px mouth (e.g. not fully cured, sharp edge surfaces)
115
In what 2 ways can we assess Px has correct vertical dimension with occlusal rims?
1. Freeway space (2-4mm) - measured with Willis Gauge or Callipers 2. Observe Px swallow and speak (esp. "s" sounds - ask to count from 60-70)
116
On new denture fit appt, what should be checked before placing dentures in the mouth? (4)
* Saddle borders - Sharp surfaces or over-extention
* Acrylic fit surface - Sharp edges, acrylic pearls
* NO Acrylic flash over Co-Cr surfaces where shouldnt be
* Disinfected
117
When is the lingual sulcus largest and smallest? How can we adapt our impression taking to ensure we get an accurate sulcus size between these two?
Largest = When tongue relaxed Smallest = When tongue protruded Impression tip: Get Px to protrude tongue and lick upper lips (achieves sulcus size between relaxed and taught)
118
What are the 3 main copy denture techniques? Which is the cheapest?
1. Soap Box
2. Metal Flasks ("Murray/Wolland") - CHEAPEST (with alginate)
3. Stock Trays and Putty ("Dundee/Yemm")
119
What are 3 advantages of a single Path of Insertion?
1. Provides frictional retention 2. Minimises interference on removal 3. Directs forces along long axis of tooth
120
What are the main advantages of using an Overdenture instead of a complete denture? (2)
* Preserves alveolar bone
* Increased sensory feedback for Px → Increased biting force and more reproducable jaw movements
121
What is the ideal occlusion (class) for px with unstable occlusion in reorganised occlusal approach?
Class I (Otherwise, we must harmonise with Px existing occlusion)
122
How can we determine the occlusal relationship that used to exist in the natural dentition of a now edentulous patient? (5)
1. Analyse skeletal relationship 2. Analyse anatomical landmarks (E.g. Incisive papilla and Palatal Gingival Remnant - Maxilla) 3. Look at old photos 4. Analyse muscular activity 5. Functional recording of "Denture space" (E.g. Piezography)
123
In toothwear cases, what are the 2 main definitive restoration/prostheses?
1. Build up teeth with fixed restorations and any missing spaces filled with conventional denture (doesnt lie over natural teeth)
2. Increase/restore OVD with Onlay denture, Overlay denture or Overdenture
124
In terms of denture _design_, what are the main causes of Mid-line fractures? (5)
* Thin palate
* Open-flanged denture (no flange on buccal/labial aspect)
* Deep frenal notch
* Teeth set with mid-line diastema
* Midline palatal torus on upper - *Not relieved on master cast*
125
What happens if RCP DOES NOT = ICP in Complete denture (for edentulous Px)?
Results in a: "Horizontal occlusal error" Where teeth do NOT intercuspate in RCP
126
What information should be included on a lab card?
Px name, DOB & address Clinician name & Signatures Denture design & attached instructions for lab technicians
127
What important requirements must be met for placement of a mandibular: 1. Lingual Bar? 2. Dental Bar?
1. 3mm gingival margin clearance and AT LEAST 7mm between gingival margin and floor of mouth (7-8mm) 2. Rigidity (4mm depth & 2mm thickness) and AT LEAST 8mm crown height on incisors
128
What is a dentures main form of: 1. Support? 2. Retention?
1. Rests 2. Clasps (direct retention) N.B. Rests also provide indirect retention but main purpose is Support
129
How can Impression materials be classified according to properties of set material? (3)
(Hint: Think normal groupings)
1. RIGID *- Impression Plaster, Impression Compound, ZOE*
2. ELASTOMERIC *- Addition/Condensation Silicone, Polyether, Polysulphide*
3. HYDROCOLLOID - *Agar (Reversible) or Alginate (Irreversible*
130
What can cause gagging with dentures in place?
* Loose upper denture (fit or polished surface)
* Increased OVD (occlusal surface)
* Lack of tongue space (polished surface)
* Denture extended too far, onto soft palate
131
What are the 2 main types of special trays for Master/Secondary Impressions?
What is the difference and what impression materials are usually used in each?
(HINT: Based on fit)
1. CLOSE-Fitting *-* Lower viscosity (Mucostatic) materials: *ZOE or Light-bodied Silicone*
2. SPACED Fitting (For when undercuts to be recorded) - Higher viscosity materials: *Alginate or High/Medium-bodied Silicone*
(SPACED Fitting Special Trays should be 2-3mm away from full sulcus depth)
132
What is it called when a patient with toothwear has a NORMAL freeway space?
Alveolar compensation
133
What is meant by:
1. Bracing?
2. Reciprocation?
What is the difference?
1. The resistance of RIGID components of the DENTURE against horizontal forces (E.g. Reciprocating/Bracing Arm of Clasp, Plate or Minor Connector)
2. The principle of horizontal resistance to TOOTH MOVEMENT that may occur during clasp engagement
Where Reciprocation is concerned with horizontal TOOTH movement, Bracing is concerned with horizontal DENTURE movement (both are at work on the bracing/reciprocal arm of a denture clasp, which lies ABOVE the survey line)
134
Which type of Kennedy class denture can rely on Indirect retention alone? Whereas all 3 other classes require direct retention (clasps) ?
Kennedy Class 3
135
What are 4 features of a good impression?
1. Good extension (sulcular depth and palatally)
2. Rolled-Borders
3. Visible Anatomical Landmarks
4. No Surface defects (e.g. bubbles, tears, air blows)
136
What are 4 types of MAXILLARY Major connectors? Which is 1st line? (HINT: They all begin with Palatal)
1. Palatal Bar (Anterior, Middle & Superior) - 1st Line 2. Palatal Strap 3. Palatal Plate 4. Palatal Horseshoe
137
At what 3 stages/phases in casting would we want to articulate casts?
1. Primary casts - Conformative approach w/sufficient occlusal contacts 2. Master casts BEFORE Framework construction (Reorganised occlusal approach, increased OVD) AFTER Framework construction (Conformative)
138
What is meant by:
1. Mucostatic?
2. Mucocompressive/displacive?
(Give examples of each)
How does this affect denture :
1. stability?
2. retention?
_MUCOSTATIC_ = Less viscous impression material that doesn't displace soft tissues and records an impression of the _un-displaced_ mucosa
1. Improved retention (close adaptation to tissues at rest)
2. LESS STABILITY of denture in function (as tissues distort)
E.g. ZOE, Impression Plaster, Low-viscosity Alginate and **Light-bodied/Wash Addition silicone**
_MUCOCOMPRESSIVE_ = Viscous impression material which causes soft tissue displacement and records an impression of the mucosa under load
1. Improved stability
2. LESS RETENTION as soft tissues return to original position at rest
E.g. **Impression Compound, High-viscosity Alginate, PolyEther** and **Heavy-bodied/Putty Addition Silicone**
139
What are 5 actions of rests in dentures?
1. SUPPORT (prevent gingival trauma) 2. Indirect Retention (provide lateral stability) 3. Prevent food packing between abutment tooth and denture 4. Transmit occlusal forces down long axis of tooth 5. Maintain correct occlusal relationship (vertical height) of denture base to abutment teeth
140
What is meant by an Overlay denture or Overdenture?
Removable partial or complete denture that gains additional support by covering one or more existing teeth, existing roots of natural teeth or implant-retained
141
What is a form of: 1. DIRECT Retention? 2. INDIRECT Retention?
1. Clasps
2. Rests
142
In the placement of rests, what are 3 reasons for preparation of teeth to form "Rest seats"?
1. Provides enough occlusal space to allow suitable metal thickness to withstand forces (at least 1mm) 2. More suitably inclined bearing surfaces for teeth vs. those existing on natural teeth 3. Provide surface shape allowing desirable amount of bracing
143
What are 3 possible Contraindications for a SDA ?
1. Anterior open bite
2. Existing parafunctional habits (e.g. leading to excessive toothwear)
3. TMJ problems
144
What is meant by a "Biometric Guide"? (give an example)
An aid to identifying the position of artificial teeth E.g. Occlusal Rims!
145
What is meant by a denture Reline?
What are 3 advantages to it?
_Addition_ of material (RT Cure PMMA) onto denture fit surface to improve overall fit
1. Can be done at chairside
2. Improves fit (retention) of ill-fitting dentures
3. Can be temporary or permanent
146
In cases of toothwear, is treatment better tolerated when freeway space is:
NORMAL?
INCREASED?
INCREASED
(As prostheses will RESTORE the vertical dimention)
Whereas, in normal FWS (due to alveolar compensation) the prostheses will INCREASE the FWS - Provisional appliance (e.g. splint) required
147
Does the upper or lower denture have more support? WHY?
UPPER - Larger fit surface - Firmer support (palate) N.B. Also least likely area to cause trauma as occlusal forces are distributed over a greater surface area
148
In what 2 ways can you reinforce a PMMA denture base for a px whos denture keeps breaking? (DM)
1. Fibre Reinforcement - Carbon, Glass, Aramid/Kevlar or UHMPF
2. Addition of Rubber Phase (E.g. Butadine Styrene)
149
Describe the sequence of adjusting the maxillary occlusal wax rims (6 steps with anatomical reference points)
(N.B. LOWER IS OFTEN DONE FIRST)
1. LIP SUPPORT - Ideally 90° (Follow Naso-labial angle or position of incisal papilla: 8-10mm between IP and labial denture surface)
2. ANTERIO-POSTERIOR HORIZONTAL PLANE ORIENTATION - (Follow Ala-Tragal line)
3. LIP LINE - (17-21mm below ANS)
4. ANTERIOR HORIZONTAL PLANE - (Parallel to interpupillary line)
5. ARCH WIDTH - (10mm Palatal Gingival Remnant to outer buccal denture surface)
6. VERTICAL DIMENTION - (2-4mm FWS)
150
What is the definition of:
1. RVD ?
2. OVD?
3. Freeway Space? (What is the ideal)
1. Superior-inferior relationship of the maxilla and mandible when the teeth are at rest
2. Superior-interior relationship of the maxilla and mandible when the teeth are in maximum cuspation
3. FS = RVD - OVD (Ideally 2-4mm)
