Construction of complete dentures - clinical steps Flashcards

1
Q

What is the purpose of jaw registration?

A

Record the occlusal relationship (between maxilla and mandible in this case) to produce a prosthesis that is functional and comfortable

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2
Q

Define intercuspal position (ICP)

A

Position where the teeth are in maximum interdigitation, and it is usually the habitual bite of the patient

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3
Q

Define retruded contact position RCP

A

The position of the condyles in the most superior, retruded position in the glenoid fossa of the maxilla

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4
Q

Why is RCP used in jaw registration?

A

It is the most reproducible position when there is no ICP (edentulism)

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5
Q

Define occlusal vertical dimension (OVD)

A

Distance between an arbitrary point on the maxilla and the mandible when the patient is in ICP

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6
Q

Define resting vertical dimension (RVD)

A

Distance between an arbitrary point of the maxilla and the mandible when the patient is at rest

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7
Q

Define freeway space (FWS)

A

Interocclusal space between the teeth at rest and when the head is upright

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8
Q

Define balanced occlusion

A

Simultaneous anterior and bilateral posterior contact of teeth in centric and eccentric positions

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9
Q

Why is balanced occlusion important in complete dentures

A

Prevents dislodgement of the denture via tripodisation

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10
Q

What occlusion should be avoided in complete dentures?

A

Anterior guidance (incisal and canine)

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11
Q

What are the main steps in jaw registration?

A
  • Check rims on cast
  • Check upper rim alone and adjust
  • Check lower rim alone then adjust according to measurements taken
  • Take bite registration
  • Shade and mould
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12
Q

What do you assess when the occlusal rims are on the cast?

A

Retention (fit), extension, stability

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13
Q

What types of material can the occlusal bases and rims be made of

A
  • Wax and wire reinforced wax

- Acrylic bases

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14
Q

When can existing dentures be used in jaw registration?

A

Patient happy with aesthetics - can use copy denture

Use in OVD/RVD measurement if occlusion is good

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15
Q

List the steps you do to adjust the upper rim

A
  • Labial and buccal support
  • Occlusal plane adjustment
  • Markings: length of teeth, midline and canine line
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16
Q

How to adjust labial support in upper rim

A
  • Too bulky - remove wax 3-3

- Unsupported - soften wax, add it 3-3 until happy

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17
Q

How much of the upper incisors should be visible at rest

A

Around 1mm

Take into account pts age (less teeth showing as you age)

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18
Q

How to ensure the correct occlusal plane is translated to the occlusal rim?

A
  • Parallel to interpupillary line

- Posteriorly parallel to the camper’s line (ala tragal)

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19
Q

How to mark the midline on the upper rim

A

Use the midpoint of the interpupillary line

Avoid midline of the face as it may be asymmetrical

20
Q

Where do you mark the canine line

A

Inner corner of eyes/outer part of nose

21
Q

What do you adjust in the lower rim

A
  • Labial and lingual aspects to the rim is not dislodged on movement of lips or tongue
  • Occlusal plane should lie just under the tongue posteriorly
  • Trim until parallel with upper
  • Trim to match planned OVD
22
Q

How to get patient into RVD naturally

A

Lick lips and swallow, their lips should be slightly parted

23
Q

What instruments do you use in RVD/OVD calculations

A

Calipers

Willis bite gauge

24
Q

How do you calculate OVD

A

(RVD - FWS) = OVD

25
Q

How many mm is FWS

A

2-4mm

26
Q

How do you record the occlusal relationship after adjustments have been made?

A
  • Cut notches into the rims
  • Place upper rim in situ
  • Bite reg material applied to lower rim
  • Place lower rim in situ
  • RCP until set
  • Assess
27
Q

List the types of bite reg materials

A
  • ZOE
  • Wax
  • Silicone
28
Q

List the + and - of ZOE as bite reg material

A

+ cheap, dimensionally stable, setting time reduced by adding warm water
- allergies, avoid if xerostomia, long setting, messy

29
Q

List + and - of wax as a bite reg material

A

+ cheap and accessible

- hardens quickly which can cause propping open at the back

30
Q

List + and - of silicone as a bite reg material

A

+ Dimensionally stable, good detail

- sets quickly, expensive

31
Q

How should the occlusal bases and rims fit in the mouth

A

Should extend to the full sulcus depth and correct posterior extension (provided from secondary impressions) to be retentive

32
Q

How can the ‘f’ sound help in placement of teeth

A

Incisal edge of upper incisors meets the dry-wet border of the lower lip - good position for incisal edges

33
Q

Excess OVD means there is…

A

Insufficient FWS

34
Q

Insufficient OVD means there is..

A

Too much FWS

35
Q

What are complaints with excess OVD

A
MOM fatigue 
Excess show of lower teeth 
Clicking of teeth when speaking 
Strained appearance of lips 
Uncomfort or gagging 
Excessive trauma to tissues
36
Q

What are the complaints with insufficient OVD

A

Ageing of the lower face (wrinkles, chin close to the nose, overlapping of corners of lips)
Insufficient occlusal force
Angular cheilitis

37
Q

What are the aims of wax try in?

A

Verify occlusion, aesthetics, phonetics, comfort with the patient before the denture is processed

38
Q

What are the types of biometric guides for tooth positioning (complete dentures)?

A

Extraoral

Intraoral (maxillary and mandibular)

39
Q

What are the extraoral biometric guides for tooth positioning (complete dentures)?

A
  • Camper’s plane for posterior occlusal plane
  • Interpupillary line for occlusal plane
  • Midline of face or IPL for dental midline
  • Outer corner of alae for canine tips
  • Lips for incisal edge positioning
  • Width of nose is 4x bigger than the width of centrals
40
Q

What are the maxillary biometric guides for tooth positioning (complete dentures)?

A
  • Incisive papilla (8-10mm)
  • Alveolar ridge - teeth placed buccal to this
  • Palatal gingival vestige - position of posterior teeth
41
Q

What are the mandibular biometric guides for tooth positioning (complete dentures)?

A
  • Alveolar ridge posterior - central fossae should overlie
  • Alveolar ridge anterior - teeth anterior to ridge
  • Retromolar pad - occlusal plane level with anterior RMP
  • Maximum convexity of the tongue - lat border of tongue rests on lingual cusps
42
Q

How is tooth positioning determined by palatal gingival vestige

A
Distance between the vestige and labial/buccal surface of the teeth should be 
6mm incisors 
8mm canines
10mm premolars 
12mm molars
43
Q

How to make sure the head is in the right position when taking RVD calculations

A
  • Frankfort mandibular plane angle should be horizontal
44
Q

How do you use a willis bite gauge?

A

Measures from base of the nose to the underside of the chin

45
Q

How do you use calipers?

A

Dot drawn on nose and chin

C/I if bearded patient

46
Q

What can be used as an addition to occlusal relationships and why?

A

Facebow to help mount the maxillary cast to the articulation

47
Q

What is special about posterior denture teeth and why?

A

They are narrow to increase masticatory efficiency