Complete Dentures

Question 1

what are the clinic and lab steps to make a set of dentures?

Answer 1

1. take primary impression
   - ask lab to cast model and make special trays
   - survey the model and come up with denture design
2. take secondary impression w/ special trays, modify if needed w/green stick
   - ask lab to make wax rims/bite blocks
3. check wax rims fit/record occlusion by measuring RVD and desired OVD
   - inform lab of the type of articulator, incisal relationship, shade and mould of teeth and any special instruction on appearance
   - ask to make trial dentures
4. wax try in of trial dentures - check the set-up on the articulator
5. fit the dentures
6. review

Question 2

what do you need for a good impression?

Answer 2

the entire denture bearing area
- full sulcus depths
- no distortion
- no air bubbles
- imp to stick to the tray

Question 3

how do you take a primary impression? and what 3 materials can you use?

Answer 3

use a stock tray

alginate - use adhesive

silicone or compound

Question 4

how do you take a secondary impression? what must the tray be if using alginate?

Answer 4

with a special tray
- if alginate, try must be perforated

Question 5

how do you construct a special tray?

Answer 5

• on the model, outline the special tray
• create stops
• place acrylic in the stops
• place acrylic over the entire model and adapt
• cut material to desire
• place a handle
• light cure
• use acrylic bur to remove any sharp edges

Question 6

what does adding a spacer to the tray ensure?

Answer 6

that there is sufficient space for the impression material to flow - if it is a close fitting tray, do not add a spacer

Question 7

what do stoppers allow on the denture tray?

Answer 7

• stops the tray from being pushed all the way down, allowing space for the imp material
• ensures that the impression material remains at a constant thickness

Question 8

what materials require perforated trays?

Answer 8

alginate

• compound and silicone don’t

Question 9

what stock trays are used for edentulous patients?

Answer 9

box trays
they’re not rounded on the inside as you dont expect there to be teeth

Question 10

give 4 pros and 2 cons of compound material

Answer 10

pros
- non-toxic
- easy to use
- can be re-softened
- muco-displasive
- doesn’t require adhesive

cons
- poor surface detail - can take an alginate over it
- poor dimensional stability

Question 11

pros and cons of alginate

Answer 11

pros
- easy to use
- elastic
- viscous
- good surface detail
- mucostatic

cons
- poor stability - needs to be cast asap
- can’t add onto it
- dries out easily
- poor tear resistance
- requires adhesive
- any unsupported alginate is likely to distort

Question 12

pros and cons of silicone

Answer 12

pros
- easy to use
- good surface detail
- elastic
- supports its own weight
- mucocompressive

cons
- expensive
- needs tray adhesive
- long setting time
- hydrophobic

Question 13

what is the purpose of green stick or pink stick?

Answer 13

to extend the tray

Question 14

what information do the wax blocks provide?

Answer 14

the position of the teeth
the angle of the occlusal plane

Question 15

when you have constructed the wax blocks, why would you think to redo the secondary imp?

Answer 15

if the wax blocks have very poor retention and disturbing with the soft tissues

Question 16

describe the process of trying the wax blocks in.

Answer 16

• check for sharp edges
• try it in the mouth
• check the lip support - add or takeaway if necessary
• use a foxes byte plane to make sure it is parallel to eyes and parallel to the alatragus line
• try in the upper and lower
• use a willis gauge to measure the occlusion heights - need a freeway space of 2-4mm
• make any alterations on the lower if necessary for the correct oVD
• cut notches in the upper rim and mark a centre line with a wax knife
• add adhesive to the lower rim
• put blu mousse on both upper and lower
• close in retruded position
• disinfect and send to lab

Question 17

what happens if there is a lack of freeway space?

Answer 17

increased load on the TMJ and denture bearing tissues
- teeth click together then speaking

Question 18

what happens if there is excessive freeway space?

Answer 18

difficult to eat
teeth don’t show

Question 19

how much tooth should show when the mouth is at rest and what can change this?

Answer 19

2mm

if the denture is overextended at the front - mouth is lifted and too much tooth showing

if denture is underextended - lips go in and no tooth shows

Question 20

why may patients be uncomfortable with the denture?

Answer 20

over-extended dentures digging into the sulcus/lifting from the sulcus

undercuts digging into the alveolar ridge

concentrations of occlusal pressure

Question 21

if a patient presents with ulcers, what do you do?

Answer 21

check for overextensions, any sharp edges, any premature occlusal contacts

• review in a week if its healing
• refer to oral medicine if not healing

Question 22

why would a denture become loose?

Answer 22

• the alveolar bone has continued reducing and no longer is complimentary to the denture
• lack of muscular adaptation

Question 23

what is a soft lining? what is it made out of

what are the cons?

Answer 23

a lining inside the denture to cushion painful pressure points and making eating more comfortable

• made out of silicone or acrylic

Question 24

why may a denture wearing pt have pressure points?

Answer 24

sharp bony ridges
superficial mental nerve
thin atrophic mucosa
parafunctional habits

Question 25

soft lining material - silicone or acrylics, describe each

Answer 25

silicone - min thickness - 2mm - softness - always - glass trans temp - -130 degrees - bond to denture - requires bonding agent - surface finish = poor - durability - less than acrylic - prone to candida infection UHOH acrylic - min thickness - 2-mm - softness - decreases over time - glass trans temp - 20-30 degree - bond to denture - well - surface finish - good - durability - more than silicone

Question 26

what is a reline? what material can be used? cons

Answer 26

fills in the gaps between soft tissue and denture when there is a change in the shape of the tissues under the denture - fitting surface won't fit anymore material - usually acrylic cons - can increase the OVD - can increase thickness of the palate - exothermic polymerisation - monomers can be allergenic - may reduce retention - chair side won't cure the same as in the lab

Question 27

what is the closed mouth technique?

Answer 27

place light bodied silicone material in the denture - pt bites down in occlusion whilst it sets

Question 28

what is a rebase? pros vs the reliners

Answer 28

whole fitting surface is removed and replaced in the labs pros - no increase in OVD - no increase in palate thickness - can have a new post dam

Question 29

what are the pros and cons of making adjustments chairside and labs

Answer 29

chair side pros - fewer stages for error - immediate result cons - materials aren't as strong - free monomers can be allergic - material may lock into undercuts labs pros - good physical and mechanical props cons - pt without denture for some time - errors may occur throughout the stages - if heat is used, existing base material may warp

Question 30

can you use tissue conditioner to make dentures more comfortable? - what is it made out of?

Answer 30

yes for quick instant relief - will only last about a week - it can help diagnose the cause of pain, if you need to reline composition - powder - acrylic beads - liquids - plasticiser and ethyl alcohol - no chemical reaction - just gelation

Question 31

define copy denture - how is it done - pros - indications and contraindications

Answer 31

a duplicate of an existing denture - attempt to reproduce the satisfactory features and improves those meh bits 1. make a mould of existing denture 2. wax/acrylic replica 3. use as special tray and record occlusion 4. place on articulator, replace teeth with acrylic 5. wax try in, take wash impression - light bodied silicone 6. send to finish pros - similar shape to prev denture - good adaptation - saves clinical time - fewer clinical stages - fewer imps taken - more tolerable - can maintain the appearance indications - older patients - pts worn the same set for years - problems adapting to new dentures contraindications - prev dentures = unsatisfactory