Construction of complete dentures - clinical steps

Question 1

What is the purpose of jaw registration?

Answer 1

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

Question 2

Define intercuspal position (ICP)

Answer 2

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

Question 3

Define retruded contact position RCP

Answer 3

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

Question 4

Why is RCP used in jaw registration?

Answer 4

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

Question 5

Define occlusal vertical dimension (OVD)

Answer 5

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

Question 6

Define resting vertical dimension (RVD)

Answer 6

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

Question 7

Define freeway space (FWS)

Answer 7

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

Question 8

Define balanced occlusion

Answer 8

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

Question 9

Why is balanced occlusion important in complete dentures

Answer 9

Prevents dislodgement of the denture via tripodisation

Question 10

What occlusion should be avoided in complete dentures?

Answer 10

Anterior guidance (incisal and canine)

Question 11

What are the main steps in jaw registration?

Answer 11

• 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

Question 12

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

Answer 12

Retention (fit), extension, stability

Question 13

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

Answer 13

• Wax and wire reinforced wax

- Acrylic bases

Question 14

When can existing dentures be used in jaw registration?

Answer 14

Patient happy with aesthetics - can use copy denture

Use in OVD/RVD measurement if occlusion is good

Question 15

List the steps you do to adjust the upper rim

Answer 15

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

Question 16

How to adjust labial support in upper rim

Answer 16

• Too bulky - remove wax 3-3

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

Question 17

How much of the upper incisors should be visible at rest

Answer 17

Around 1mm

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

Question 18

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

Answer 18

• Parallel to interpupillary line

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

Question 19

How to mark the midline on the upper rim

Answer 19

Use the midpoint of the interpupillary line

Avoid midline of the face as it may be asymmetrical

Question 20

Where do you mark the canine line

Answer 20

Inner corner of eyes/outer part of nose

Question 21

What do you adjust in the lower rim

Answer 21

• 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

Question 22

How to get patient into RVD naturally

Answer 22

Lick lips and swallow, their lips should be slightly parted

Question 23

What instruments do you use in RVD/OVD calculations

Answer 23

Calipers

Willis bite gauge

Question 24

How do you calculate OVD

Answer 24

(RVD - FWS) = OVD

Question 25

How many mm is FWS

Answer 25

2-4mm

Question 26

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

Answer 26

- 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

Question 27

List the types of bite reg materials

Answer 27

- ZOE - Wax - Silicone

Question 28

List the + and - of ZOE as bite reg material

Answer 28

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

Question 29

List + and - of wax as a bite reg material

Answer 29

+ cheap and accessible | - hardens quickly which can cause propping open at the back

Question 30

List + and - of silicone as a bite reg material

Answer 30

+ Dimensionally stable, good detail | - sets quickly, expensive

Question 31

How should the occlusal bases and rims fit in the mouth

Answer 31

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

Question 32

How can the 'f' sound help in placement of teeth

Answer 32

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

Question 33

Excess OVD means there is...

Answer 33

Insufficient FWS

Question 34

Insufficient OVD means there is..

Answer 34

Too much FWS

Question 35

What are complaints with excess OVD

Answer 35

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

Question 36

What are the complaints with insufficient OVD

Answer 36

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

Question 37

What are the aims of wax try in?

Answer 37

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

Question 38

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

Answer 38

Extraoral | Intraoral (maxillary and mandibular)

Question 39

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

Answer 39

- 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

Question 40

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

Answer 40

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

Question 41

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

Answer 41

- 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

Question 42

How is tooth positioning determined by palatal gingival vestige

Answer 42

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

Question 43

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

Answer 43

- Frankfort mandibular plane angle should be horizontal

Question 44

How do you use a willis bite gauge?

Answer 44

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

Question 45

How do you use calipers?

Answer 45

Dot drawn on nose and chin | C/I if bearded patient

Question 46

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

Answer 46

Facebow to help mount the maxillary cast to the articulation

Question 47

What is special about posterior denture teeth and why?

Answer 47

They are narrow to increase masticatory efficiency