clinical stages of RPD design Flashcards
what occurs in visit 1
assessment and primary impressions
what occurs in visit 2
master impressions
what occurs in visit 3
framework trial
- +/- record occlusion
what occurs in visit 4
tooth trial
what occurs in visit 5
delivery/fit
what occurs in visit 6
review
how is visit 1 carried out
- examination of the patient and previous denture
- look in the mouth = feel ridge for displaced tissue, free end saddles, bounded saddles, undercuts
- fill out denture assessment form
- select a tray and try it in
- select an impression material
what types of impression trays can be used in visit 1
- dentate = deeper
- edentate = not as deep, for edentulous patients
- perforated stock trays with removable handles = handle orientation must be that it won’t lift up the lip and alter impression
what impression material is used for no free end saddles
alginate
what impression material is used for free end saddles
compound
- it can modify the tray as stock trays don’t fit everyone
- is a mixture of waxes and resin = stabilise tray for more accurate impression
- should not be used on teen as could catch on teeth
what is the most elastic impression material
alginate
- also elastomer is quite elastic = made up of silicone and polyether
what are non elastic impressions materials
- impression compound
- ZnO/Eugenol
how are primary impressions taken
- select stock tray and modify peripheries with wax or compound
- apply adhesive and use alginate or alginate/compound for impression = alginate over top of compound as a alginate wash
- disinfect and place in sealed bag with wet cotton wool/paper towel = place in perform solution to disinfect and decontaminate
- label bag and write instruction to technician
why is a wet cotton wool/paper towel placed in bag with impression
- because alginate can take on water so impression wouldn’t. be accurate so paper towel prevents this
what is recording he occlusion
- measuring how the teeth meet
what happens if you can hadn’t articulate the casts
- don’t need to record the occlusion and don’t need a primary record block or wax wafer
- you can get the casts mounters on an articulate with a wax wafer or nothing at all
- you can examine the occlusion on the articulator
- look for space to place rest seats
- plan for preparation of rest seats if moo space available
what is a wax wafer used for
- inter occlusal record
- warm wax patients bites on
- can you see any missing teeth = then not in correct occlusion
how can you tell on the articulator if occlusion isn’t right
- pin of articulator not on table
what do you do if you can’t hadn’t articulate the casts
- you need a primary record block from the lab (can’t obviously see how teeth meet together) = used to mount casts accurately
- record occlusion using primary record block
- ask technician to mount the primary casts using you registration
- if need to have a primary record block this means an extra clinical stage to record the occlusion before primary models can be mounted on an articulator = once found occlusion can mount
when can you move onto master impressions
- once you have surveyed the cast
what is used to stick the casts together in occlusion
-wax or silicon registration paste
what instructions do you need to give the technician after visit 1 for master impression
- how much spacing is required
- are there any undercuts = want it to flex/be elastic
what instructions does technician need after visit 1 if you can hand articulate
- pour primary cast
- special tray with spacer = 1-2 sheets of wax depend on master impression material with handles/fingers rests etc
what instructions does technician need after visit 1 if you can’t hand articulate
- pour primary cast = with 50/50 dental stone
- special tray with spacer = 1-2 sheets of wax depend on master impression material with handles/finger rests etc
- construct primary record blocks for a preliminary jaw registration = base can be wax, shellac or light sure acrylic
what must be done before visit 2
- design the denture
- surgery path of insertion ]- surgery to decide undercuts
- do teeth need modified for rest seat, guide planes and undercuts
- draw design on laboratory work card
what must you remember when designing the denture
- design must conform to the patients occlusion unless you are planning to change
- if there is no inter occlusal clearance for a rest either make space by cutting a rest seat or do not place a rest
- if you don’t make a space the occlusion will not be correct
- if there is no space the rest will simply open the bite
what is the system of design
- outline saddles
- support = rests
- retention = clasps
- bracing
- connectors = minor or major
- review design
when do you need to do a primary registration
- when you can’t hand articulate
what is done in visit 2
- trim peripheries if overextended
- modify peripheries with greenstick and fit surface for free end edentulous saddles
- take master impression
what is poly vinyl siloxane
- a medium bodied silicone
- is an impression material
- don’t want light bodied as too runny and heavy bodied is like putty
- don’t need a lot as have custom tray with little spacing
- brand name = Extrude
what is polyether
- an impression material
- careful with undercuts as will have to cut around these if this gets caught
- very accurate and gives good impression
- brand name = Impregum
- very rigid
what is alginate
- an impression material
- well mixed
- poured up as soon as possible
- good if undercuts are present
- careful or air blows = compromise accuracy of impression
- need to tell lab if using alginate as needs to be poured on the same day
what is impression compound use for
- modify the tray
how is the master impression taken
- try in special tray and trim peripheries if overextended = trim with burr
- modify the peripheries with greenstick and fit surface for free end saddles
- apply adhesive and sue alginate/polyether/PVS for impression
- disinfect and place ins elated bag and write instructions to technician = in perform solution
why is it important that master impressions are correct
- if not then everything after them in the process won’t be right either
why does polyether and silicon not need water
- they are dimensionally stable
what do you need to do if the denture is going to be in cobalt chrome
- pour model in improved stone
- contract chrome framework per design = clear design signed by clinician
- remember to prepare occlusal rests/guide planes before taking impression
what do you need to do if the denture is going to be in acrylic
- pour model in stone
- construct record bloc with shellac base
what happens in visit 3
- framework trials and/or not recording the occlusion
- design is agreed
- 2-3 weeks
what is considered in the framework trial
- does it fit the cast
- does it seat correctly in the mouth
- is the cast damaged
- is the framework interfering with occlusion
- if not right then adjust at chair side = wear appropriate PPE, use Adam’s pliers for claps
when do you register the occlusion
- once happy wit the framework
- check space for rests = and measure the depth of sulu, undercuts for claps
why do you need to record the occlusion
- to help design the denture
- to help the technician set-up the teeth
- to ensure the denture is stable and is not dislodged in function
- patient comfort
- ensuing loading forces are applied correctly to teeth
- conformist approach = keeping the occlusion same as it is, need to know the position of teeth in relation to each other
- re-organised approach = altering the occlusion, tooth wear, not enough teeth to meet
what is the aim of the visit for recording the occlusion
- establish inter occlusal relationship to articulate rests
- establish occlusal vertical dimension
- establish tooth moult and shade
- establish extend edentulous spaces =buccal/labial contours of wax and record block, lip support, incisal plane, posterior plane
what are you aiming for with recording the occlusion for the technician
- to inform the technician where you want the artificial teeth to be positioned their shade and mould together with information on how the teeth occlude
- wax occlusal rims for definitive registration
- made on working casts from secondary impressions
what do you need to adjust if the framework doesn’t fit in patients mouth
- if need to trim CoCr need to get the lab to do it or can do it at chair side by need special PPE
- equipment needed = hot plate, Bunsen burner, palate knife
what do you need to do if there are no index teeth
- need to measure the OVD and FWS
- OVD = occlusal vertical dimension (should be 2mm)
- FWS = freeway space (should be 2-3mm)
- use old dentures as initial starting point for OVD
why do you need to give the patient 2-3mm freeway space
to be able to speak
how and why are the blocks trimmed
- use the blocks to tell the technician where the teeth will go
- try it in, it will be bulky
- it has to stay in place = may fall out if overextended into sulcus so whenever muscles move it falls out
- any overextension of the peripheries as it will drop/displace
- too much lip support and it will drop
- use the wax knife and hot plate to make adjustments
- adjust upper rim first
- you may need to adjust the rim labially/buccally
what must you do for prescribing the position of the anterior teeth
- made sure index teeth are in occlusion
- mark centreline = for technician
- correct incisal plane
- correct anterograde-posterior position
- should follows line of lower lip
why must you ask patients for how they want the denture
- any specifics for their own teeth they want replicated
what articulator will you use most of the time
average value articulator
what do you need to do once the framework comes back from the lab
- check it fits properly, if its damaged
- it will come on a working cast
what are the reference points
- teeth present
- dento-facial midline]- inter-pupillary line
- ala-tragus line
- curvature of lower lip
- smile line
- gingival margins of existing anterior teeth
- previous dentures
where is the alar-tragus line
- bottom of nose to the ear
- diagonal line
where is the inter pupillary line
- above the eyebrow
what needs to be considered for teeth shade and mould
- existing teeth
- previous denture
- patient performance
- measure
what is you need a record block on framework
- need an additional visit
- construct wax record blocks on chrome framework
how is the tooth trial carried out
- articulate casts to registration
- set teeth for wax trial (shade and mould provided)
what happens at visit 4
- tooth trial
- at this point should have teeth on
- framework tooth trial
what are you checking in framework tooth trial
- framework fit
- occlusion
- aesthetics
- extension
what do you do if there are any problems at visit 4
- describe change needed to technician
- do a re-trial
what can you adjust at chair side in visit 4
- teeth to lower the bit
- use hot wax
what happens in patient happy with denture at visit 4
- take to finish in acrylic
- can get small f=dimensional changes when change to acrylic however
what do you look at in the denture on the articulator at visit 4
- check design again as requested
- examine dentures for roughness/blebs
- check it seats properly
- any undercuts = check these, doesn’t always come out once it goes in
- is the pin on the table
- does occlusion look correct
what are you looking at with dentures in patient mouth
- insert dentures - does it seat properly
- if elderly patient need to make sure they can get it in and out easily
- check = stability (does it rock), support (are the rests/flanges seating accurately), retention (adjust clasps with Adams pliers), aesthetics (carry put above checks first, last thing you do is show patient
what must you check in occlusion at visit 4
- do teeth meet in the resorbed occlusal scheme our the wax up = check with articulation paper for heavy/early defective contacts
- is something propping open the bite = small change adjust with acrylic burr chair side, large change may require removal of teeth and re-set in wax
what is used to adjust denture in the lab
- hand piece and suction for debris
- operated by knee peddle under the bench
- use mop to poohs denture along with the pumice
what are the instructions you give to the patient
- coping with the new denture = will be uncomfortable at first
- pain is expected at first
- denture cleansing = should be removed at night, bacteria that can be aspirated and cause pneumonia
what happens at visit 5
- review = can be the most difficult stage
- history, examination, adjustments
- if sore, get patient to still wear it for a couple days before attending as will be more obvious as there will be ulcers at sore area
how is the occlusion recorded
- made of wax so easy to adjust
- reduce height of block until it starts to conform to patients bite
- can use silicon registration paste = patient bites together and it fits into notches made
what do you do if 2 record blocks needed
- same process as if 1
- sort out upper first then lower
- 1= identify index teeth
- 2= adjust one block to keep the index teeth in occlusion
- 3 = adjust second block with first one still in to keep index teeth in occlusion
- 4 = record occlusion
what are index teeth
- teeth you can reproducibly get bite from together, they meet
