A- C.Dentures Flashcards

1
Q

4 stages of Denture construction?

A

1- Primary impressions
2- Secondary impressions
(Recording the shape of the ridges and supporting tissues)

3- Registration
4- Wax tryin
(Establish correct placement of the denture teeth, record inter-ridge relationships, make a wax template to be converted into a denture)

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2
Q

2 stages of denture provision?

A

1- Fit stage; aesthetic, funcitonal checks… check record?

2- Post-fit Review: sore areas, aesthetic and functional checks

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3
Q

Name some maxillary structures relevant to dentures

A
  • Fovea palatini
  • Hamular notch
  • Sulcus
  • Fraena (midline? buccal)
  • Incisive papilla
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4
Q

Name some mandibular structures relevant to denture making

A
  • Retromolar pad
  • External-oblique ridge (outside)
  • Mylohyoid ridge (inside)
  • Sulcus
  • Lingual gingival remnant
  • Mental foramen
  • Genial tubercles
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5
Q

Purpose of primary impressions?

A
  • Record anatomy
  • Permit primary models to be cast
  • construction of special trays to record working 2ndary imps
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6
Q

What imp material is used to take primary imps?

A

STiff viscous mix of alginate
- Displaces soft tissues (lips, tongue, cheeks) of denture bearing area

Bonding agent must be applied to tray as mechanical retention via perforations is insufficient.

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7
Q

Where and what height/ angle is mandibular primary imps taken?

A

In front of px.
Mandible= elbow height
Px sat at 60 degrees.

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8
Q

Where and what height/ angle is maxillary primary imps taken?

A

BEHIND, px right shoulder.
Px head= diaphragm level,
maxilla= elbow height

60??

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9
Q

How to take a primary imp

A
  • Take impression
  • Trim excess alginate (overextended, bulky periphery, undercuts)
  • Wash impression with low-visc alginate “runny mix”= for resolution
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10
Q

What kindof tray should be requested from primary imps (by the lab)

A
  • Close fitting
  • Non perforated
  • for ZoE imp
  • Made 1.5mm short of functional depth of sulcus
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11
Q

What resorbs more- Max or Mand and by how much?

A

Mandibular resorps 4x MORE than max.!!

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12
Q

Describe the site and pattern of bone resorption in max and mand.

A

Max- (buccal resorbs) Palatal movement (in)

Mand- in at front, out at back

Ant.- lingual movement
Post- Buccal movement.

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13
Q

Name 3 influencing factors of bone resorption

A

1- systemic; osteoporosis
2- Local; retained roots preserve alveolar bone
3- denture-induced; denture wearing can contribute to resorption

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14
Q

Name some problems that can occur with dentures

A
  • Insecurity
  • occlusal problems
  • pain
  • appearance
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15
Q

Cause of denture insecurity?

by bone resorp

A
  • ill fitting

- outside neutral zone

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16
Q

Causes of occlusal problems?(by bone resorp)

A
  • Crossbite

- Resorption

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17
Q

Causes of pain ? (by bone resorp)

A
  • Sharp, resorbed bony ridges
  • Relative movement of mental foramen puts pressure on nerve
  • irreg. resorp, mucosa becomes sandwiched between bone and denture
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18
Q

For secondary imps, if ridge has large undercuts what to use?

A
  • Elastic imp material

- Spaced special tray

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19
Q

What are flabby/fibrous ridges?

A
  • Due to fibrous tissue deposition
  • Common in upper anterior region
  • Can occur when natural teeth oppose edentulous ridge
  • use a window box for imps
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20
Q

Aim of secondary imps?

  • use close fitting trays with ZoE paste (can use alginate or silicone as well)
A

Accurately record denture bearing areas and functional sulcus.

  • Muscle insertions
  • Anatomy
  • Border moulding
  • Clear frenal attachments

For stability and retention of dentures…

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21
Q

Problems that imps can have :

A
  • air blows
  • tray showing through at periphery
  • tray showing through fitting surface
  • material pulling away from tray and sticking to ridges
  • knife edge ant. peripheral recorded
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22
Q

Vertical and Horizontal measurements for wax registration rims

A
  • Alma gauge readings for the old dentures

Standard: V22 upper V18lower

23
Q

Name 2 vertical jaw relations

Measured between 2 marked points,

  • condyles in retruded positon
A
  • Rest face height
  • Occlusal fh

RFH and OFH

“2 definable, reproducible, inter-maxillary positions”

24
Q

What is the FWS?

A

Difference between RFH- OFH

25
Ideal FWS?
2-4mm
26
Name 2 horizontal jaw relations
1- Intercuspal position | 2- Retruded contact position
27
What is ICP?
Max and man. teeth are in maximum intercuspation (centric occlusion)
28
What is RCP?
- Heads of condyles are in most superior part of glenoid fossa - First point of contact - when mandible rotates around hinge axis
29
What is the interpupillary line?
IPP- imaginary line passing thorugh pupil- guide for parallel
30
What is the Alar-tragus line? - Can be determined with Fox-bite plane guide
imaginary line passing thorugh ala of nose and tragus of ear.
31
List the 8 steps of registration
1- Mark fixed reference points on nose and chain 2- Measure and record RFH and OFH of old dentures ( determine what the OFH of new d. should be) 3- Upper wax rim: Add lip support, adjsut occlusal plane to IPL and ATL 4- Insert lower rim: guide into Retruded position, add wax until even contact; then remove evenly ti pre-determined OFH level. 5- Mark centre and canine lines and cut finger notches in premolar region of LOW. rim 6- Record the retruded jaw relationship with occlusal registration paste (silicone) 7- Select tooth mould and shade 8- Disinfect and lab prescription: Describe any variations in tooth arrangement etc.
32
Purpose of wax try-in?
Check elements vital to success of complete dentures prior to final processing
33
Things to check at wax try-in stage
- Aesthetics (size, shade, arrangement) - OVD - Desired FWS - Occlusion; ICP= RCP? - Border extensions - Border thickness - Neutral zone issues- tongue not constricted and lower teeth not out of NZ - Lip support, centre and horizontal lines - No undercuts!
34
What else to do at wax try-in stage?
Mark post-dam on cast Ball burnisher to palpate hard/soft palate junction- find compressible areas.
35
How to achieve balanced articulation with dentures?
Desirable to have multiple contacts on both sides of the denture (in lateral and protrusive movements) - prevents denture tipping
36
What is curve of spee?
Antero-posterior movement curve - Steep cusps posteriorly - Shallow cusps anteriorly (to maintain contact)
37
What is curve of Mason
Lateral movements - Rotating around working condyle - Shallow cusps on rotating side - Steep cusps on translating side (to maintain contact)
38
What soft-tissue relationships should be checked?
Visibility- should have 0.5-0.66 of incisors showing Lower lip line should coincide with incisors "tooth-lip harmony)
39
What is the post-dam?
the ridge on tissue along post. border of upper denture is used to make air-tight peripheral seal with soft palate to hold denture in place
40
What happens at denture-fit stage
1- Cotton wool test for rough areas on fitting surface 2- Insert and correct obvious faults of pain and undercuts 3- Check occlusion and correct- DEEPEN fossae 4- Check articulation- reduce CUSPAL HEIGHTs (BULL rule) Precentric check record for more major defects
41
What is a pre-centric check record?
Used when there is obvious gap between opposing teeth/ obvious slide between ICP and RCP "method of re-registering coincidence of ICP and RCP" - Mount on articulator? - Identify contacts - Deepen fossae - Articulating paper? Silicone registration paste?
42
Post-fit review stage
- Listen to complaints - Pain correction - Check occlusion - Pressure spots with PSI paste - Overextensions - Steradent to clean dentures
43
How to identify small painful areas?
Can put small amount of ZnO paste on dry sore area in mouth, insert denture and it will transfer onto it.
44
What can cause painful dentures?
- Overextensions, peripheral pain - Bony areas, central pain pressure/ undercuts - sore ridge over diffuse area= lack of FWS/ Occlusal problems
45
Common ulcer sites
- mylohyoid region - hamular notch - post dam - around frenal attachments - genial tubercles (atrophic mandibles)
46
Causes of numbness/shooting pain?
Superficial mental nerve
47
What might cause speech problems?
- teeth position - shape of base - lack of FWS
48
What might cause insecurit when eating?
Occlusal interference - occlusal error - locked occlusion? - premature contact on RHS (lack of left contact)
49
Cause of nauseau from dentures?
- Insecurity - Thick posterior margin (should be knife edge) - Intolerance of thick margins
50
Causes of loose dentures?
- Peripheral/muscle insertions - Polished surfaces and tooth position reasons: - food gets trapped underneath when eating... occlusal problem
51
What are the Polished surfaces and tooth position reasons that might lead to lower denture instability?
- if denture rises when mouth opens: - anterior teeth set too far forward (labial) - Bulky labial surface - Polished buccal surfaces
52
Why might it hurt when swallowing?
Overextension in hamular region (maxillary) or sublingually (RMP?)- reduce accordingly
53
How to resolve tongue cramping?
Eased by: - reducing palatal cusps of upper denture to increase tongue space - thinning polished palatal surfaces of cusps
54
How to resolve cheek biting problems?
- Reassure - Check occlusion for obvious gaps where cheek falls in to - Remove 7s?? - often not in occlusion and results in cheek biting