Dentures

Question 1

Steps to denture construction

Answer 1

Primary impression
Secondary impression w specialised tray
Relationship bw maxilla and mandible and measurements are taken - wax registration blocks
Wax model
Denture fit
Denture review

Question 2

Anatomical structures of maxilla and mandible

Answer 2

Fovea palatini - at soft palate/hard palate interface
Hamular notch - marks distal border of denture where tensor palatini inserts into soft palate.
Pterygomandibular raphe.
Incisive papillae
Frenal attachments

External oblique ridge and mylohyoid ridge
Retromolar pad
Insertion of genioglossus and mentalis

Question 3

Clinical techniques used when taking primary impressions

Answer 3

Firm pressure on premolar region
Border moulding
Extend impression tray by adding greenstick compound

Question 4

Problems affecting the treatment (denture provision)

Answer 4

Age - can’t adapt to the new denture
Tooth loss
Alveolar resorption

Question 5

patterns of alveolar resorption

Answer 5

Maxilla - moves palatally and gets shorter (buccal cortical plate resorbed)
Mandible - anteriorly moves lingually but posteriorly moves buccally bc of the mylohyoid ridge.
Mandible = 4x resorption as maxilla.

Question 6

Effects of alveolar resorption

Answer 6

Loose dentures - add soft liner.
Decreased face height and angular chelitis.
Irregular = sharp protrusions that traumatise the soft tissues under and cause ulcers - surgically smooth bone.
Changes to occlusion e.g. crossbite and anteriorly incisal edge-to-edge contact.
Pain due to the mental foramen becoming superficial - use a soft liner.
Not enough resorption = thin denture that breaks often or denture that reduces the FWS/increases OVD

Question 7

Factors that influence alveolar resorption

Answer 7

Systemic factors e.g. osteoporosis
Denture wearing
Anatomy e.g. retained roots or implants

Question 8

Requirements of working impressions for patients with larger undercuts

Answer 8

Elastic material in a spaced specialised tray - can space certain parts of tray and use ZnO/Eug instead.

Question 9

Requirements of a working impression for patients with no undercuts

Answer 9

Rigid material in a close-fitting specialised tray.

Question 10

Use of ZnO eugenol for impressions

Answer 10

Mucostatic in a spaced tray or mucocompressive in a non-perforated close fitting tray.
Cheap, easy to use, accurate, good surface reproducibility.

Question 11

Using alginate for impressions

Answer 11

Spread evenly in at least 3mm layer to prevent distortion

Question 12

Using silicone for the impressions

Answer 12

For fibrous ridges + windowed tray, and for undercuts. Need a thickness of 1.5mm to avoid distortion.

Question 13

What is a tissue stop used for

Answer 13

to ensure that the impression materials are at optimal thickness. Stops dentist over-pushing tray.

Question 14

Use of an alma guage.

Answer 14

Indent in denture a incisive papillae. Measures distance from here to incisal edge and labial surface of incisal teeth - for wax blocks.

Question 15

Verticle positions

Answer 15

RFH - don’t change
OFH
FWS = 2-4mm
increase OFH = decreased FWS.

Question 16

Horizontal positions

Answer 16

ICP
RCP - most posterior position of mandible. Guided occlusal and first teeth to contact. Reproducible and reliable and based on anatomy.
CR - most anterior posterior position of condyle in fossa.
ICP = RCP is ideal.

Question 17

Fox plane guide

Answer 17

Checks denture is parallel to interpupillary line and aga/tragus (Camper’s) line.

Question 18

Clinical procedure for jaw relationship and registration stage

Answer 18

Verticle measurements
Horizontal measurements
Fox plane angles
Lip support and tooth positions (canine and midline)
Tooth shape, shade and size
Notch Upper and lower and use bite registration paste to hold them together in RCP.

Question 19

What do u need to check for wax try-in

Answer 19

Teeth aesthetics and lip/soft tissue support
Post-dam
Tongue space
Border extensions and thickness.
OVD/OFH
Occlusion/ICP
Neutral zone balance

Question 20

Info needed for lab at wax registration block stage

Answer 20

OVD
RCP
Occlusal plane
Lip support
Centre line

Question 21

Curve of spee

Answer 21

Antero-posterior line

Question 22

Curve of Monson

Answer 22

Lateral movement line

Question 23

Occlusal balance for dentures during movement

Answer 23

Want ICP = RCP
Lateral movements need group function e.g. can’t rely on canines like normal dentition bc denture will tip.
Contacts on the non-working side

Question 24

Problems with the post dam at wax try in stage

Answer 24

Over or under extended

Distortion of impression or denture = post dam pulls away at back so no seal. Cut deeper post dam on the model.

Question 25

Faults to check for during insertion stage

Answer 25

Run cotton wool on the fitting surface to check for sharp bits.
Lateral and anteroposterior movements e.g. articulation and occlusion (BULL buccal upper lingual lower) - adjust cusps for articulation and fissures for occlusion (need to include first molars at least).
Check RCP = ICP
Retention
Overextended borders, post-dam
PSI paste on the inner surface and take an impression to see where the high points are - use vaseline bc sticks to mouth. Adjust these spots w a bur to reduce ulcers.

Question 26

Instructions to give to patient after insertion stage e.g. when they first get the denture.

Answer 26

Ulcers and some pain is normal

Hygiene - clean mouth and denture and don’t sleep in it to prevent denture stomatitis/candida infections.

Question 27

Common problems at review stage

Answer 27

Pain
Insecurity/looseness
Nausea
Trouble speaking/eating
Aesthetics

Question 28

Pain at review stage caused by ..?

Answer 28

TMJ problems - poor occlusion or lack of FWS so always clenching.
Ulcers due to pressure spots
Trapping of tongue or cheeks if the denture is extended too far back or buccally.
Numbness bc denture pressing on mental foramen - add soft liner.

Question 29

Insecurity/looseness of denture (review)

Answer 29

Due to trapped frenal attachments
Bad post dam/periphery seal.
Overextension or lingual undercuts from the teeth.
Can fix underextensions using self-curing acrylic.

Question 30

Chewing problems (review)

Answer 30

Looseness or reduced FWS or occlusion problems (adjust the teeth contact points using articulating paper).
Can use gothic arch tracing to find CR.

Question 31

Speech problems (review stage)

Answer 31

The patient can’t get used to denture or occlusion problems (lack of FWS, tongue cramping = lisp)
or looseness due to muscle interference.

Question 32

Nausea (review stage)

Answer 32

Post-dam is too posterior or pressing down on the back of the tongue. Looseness can make nausea worse.

Question 33

Denture faults at the insertion stage

Answer 33

Patient related - anatomy and local pathology
Lab - damage to models or poor processing
Clinician - lack of FWS, impression errors.

Question 34

Removing pressure spots at post-insertion/review stage

Answer 34

Use dycal or ZnO directly onto the ulcer and then transfer to denture by taking imp and adjust that area, or use PSI paste if general.

Question 35

How is retention of the denture caused

Answer 35

Suction (peripheral seal), adhesion and cohesion (saliva, wettability), muscular forces.

Question 36

Problems with primary impression trays

Answer 36

A bad fit can cause over-extensions or thick uneven material = shrinkage and distortion.

Question 37

What makes a good impression

Answer 37

Accurate reproduction of surface detail 
Viscosity
Wettability 
Dimensional accuracy and stability 
Shrinkage on setting 
Cooling contraction 
Permanent set 
Storage stability 
Type of tray

Question 38

How can you find CR

Answer 38

Gothic arch tracing