Complete Dentures: Clinical Problems and Solutions Flashcards
when can people start getting problems with their complete denture?
- straight after fit
- ongoing chronic problems for over several years (pt may come in with previous dentures from years ago showing you multiple unsuccessful attempts) = we need to find out root cause
what are the different clinical problems associated with complete dentures?
where is pain most likely to occur ?
- lower jaw where the area available for distribution of the occlusal load is small (lower only has ridge whereas upper has hard palate )
- pain can be either from denture factors or pt factors
what are the denture factors that can cause pain beneath dentures ?
- chemical irritation/ allergic rxn
- denture faults = impression surface, polished surface (ie surface next to buccal mucosa) , occlusal surface
what are the patient factors that can cause pain beneath dentures ?
1) generalised pain: due to overloading denture bearing area from either high occlusal forces, reduced denture bearing area (resorbed ridge) or reduced tolerance (atrophic mucosa or xerostomia)
2) localised pain = local factors such as retained roots, bony undercuts or shallow mental nerve due to resorbed ridge
multiple aetiology possible
what are the the denture factors relating to instability and poor retention?
impression surface
polished surface
occlusal surface
what are the patient factors related to instability and poor retention ?
- slow rate of adaption (ie as pt gets older)
- neuromuscular disorders eg. parkinsons
- flabby mucosa
- born resorption
- reduced saliva flow
multiple aetiology possible
what are some denture faults that can be identifies in the impression surface ?
- inaccurate fit
- over extension
- under extension
- surface roughness
- extension to bony undercuts
- cast damage before processing
how can we identify minor inaccuracies of the impression surface?
apply thin layer of fizzy paste on fitting surface, insert in pt mouth, try to do boulder moulding and ask pt to speak
- can result in poor stability and retention and pain
how do we readjust overextensions after identifying them using fizzy paste?
- polish or trim using acrylic bur
- can send to lab to get re polished
how do we prevent inaccuracies in fitting surface of denture?
good primary impression
what is a good primary impression ?
- defined denture bearing area
- records key anatomical land marks
- records full depth of sulcus
- are over-extended (modified later on taking secondary impression)
what do we request the lab when making a special tray?
special tray needs it be:
- 2mm short from the full depth of sulcus
- appropriate spaced based on the impression material planned fro use in the master impression stage
- if using alginate or medium silicone = 3mm spacing in special tray (2 layers of wax)
- if using ZnO/ eugenol (very sorbed ridges = need to request tray that’s close fitted
what are we aiming for when taking a secondary impression?
- accurately record the denture bearing area
- record entire FUNCTIONAL denture bearing area to ensure maximum support, retention and stability for the denture during use = ensure comfort for pt
- record the functional depth and width of the sulcus = creates a border seal required for improved retention
- record post dam area = for good border seal and retention
how do we record full depth and width of functional sulcus ?
- in secondary impression stage
- border moulding
- materials we can use: impression compound either pink stick 37 deg or green stick 45 deg
how do we know when we have achieved a good secondary impression?
- margins of material are rounded, rolled and replicate anatomy of sulcus in a functional manner
- its ok to see stops showing through the alginate /medium silicone stage as this prevents stock tray from compression soft tissues
what should we look out for on our plastered master model ?
- no voids on key anatomical landmarks
- uniform
- not broken
what are the key anatomical landmarks ?
Upper:
1. for support: the ridge, maxillary tuberosities, and the palate
*flat palate better support and easier to capture impression compared to round
2. for retention (border seal) : functional width and depth of sulcus and post dam area
Lower:
1. for support: the ridge, buccal shelf, anterior 2/3 of retro molar polar (as this is fibrous tissue compared to 1/3 of retro which is mainly fat tissue so more compressible meaning more pressure and more pain)
why should we assess soft and hard tissues and previous dentures ?
helps us identify the root cause of the probelm
what is a post dam ?
the posterior border of the maxillary complete denture is positioned at or around the position of the fovea palatini, by cutting a cuspids bow shaped groove onto the master cast
the post dam groove extends from the right to the left hauler notches and beyond just into the buccal Sulcus, enclosing the tuberosities and passing across the midline of the palate within 1 mm of the fovea palatini
what is the fovea palatinae ?
- 2 small depression in the posterior aspect of the palatal mucosa, one on each side of the midline located at he junction of the soft palate and hard palate
where is the vibrating line situated?
- slightly anteriorly or slightly posterior to the fovea palatinae
- the posterior border of the denture
where should the posterior border of the denture be seated?
should typically be located in close proximity to the fovea palatine - secondary impression should capture this - if we have a denture that has lost retain we should assess this area
what happens if pt can’t tolerate the post dam extension ?
- the position is moved forward away from soft palate in the centre by cutting a new post dam on the definitive cast.
- its important to maintain coverage of the tuberosities past the hamular notches into the buccal sulcus = prevent the denture from having poor stability in the anterior posterior segment and also provide improved retention as posterior extensions enagage in the undercut that is present in the hamualr notch
what do we explain to patient when they can’t tolerate the post dam extension and we have to bring it forward?
- less retention, less stability and less support for the denture
how can we create a post dam chair Side?
- using cold cure acrylic eg. tokuyama rebase
- thin line applied to posterior border (cut tip as too thin)
- new post dam should be carefully created with a depth and width appropriate to the pts tissues, then can be polished to adjust the depth
what do we need to tell the pt about the lower denture ?
- less retention compared to upper due to less denture bearing area covered due to presence of tongue that tends to displace and break the border seal
how do pts tolerate lower denture ?
pts tend to tolerate lower denture if they adapt to it and neuromuscular control changes after the provision of a denture to try to keep denture in situ ie. tongue itself will press the denture into position to maintain it and position of lower lip and buccal mucosa will sit over the denture to maintain the retention
what is denture stability defined a s?
- the mobility of the denture when pt talking and eating
- how stable is the denture anterior- posteriorly and laterally
how do we maintain stability in upper arch ?
- cover entire ridge height
- anterior posterior extension over tuberosities and up to hamular notches
clinically how do we check stability in upper ?
- place denture
- move A-P’ly = does it cover tuberosities? does it cover the ridge? does it engage with hamular notches ?
how do we maintain stability in lower arch >?
- entire ridge recorded
- buccal shelf area
- anterior 2/3 retromolar pad - if short = mobile denture and move A-P when pt tries to function
what are the polished surfaces?
includes buccal, lingual surfaces of teeth and is in contact with lips, tongue and cheeks
- should be in neutral zone
what can polished surfaces causes ?
- retention and stability problems = displacement when pt functions
why is the shape of the polished surface important?
it should be favourable for optimum muscle control
what can occlusal surface faults lead to ?
pain and aesthetic problems
what are the occlusal faults ?
- occlusal plane too high or low
- un balanced occlusion
- cuspal interference
- inadequate freeway space
- occlusal table too wide
- teeth not placed in correct position = impacts phonetics and aesthetics
how do we ensure correct occlusion?
- sufficient FWS needed
- RVD- OVD = 3-4mm
what does a correct FWS allow?
- pt can speak properly and clearly
- denture are in situ
- avoid overloading buccal mucosa if OVD is above what is aimed at?
What do record rims allow ?
- for the technician to determine aesthetics and -tooth placement to ensure occlusion is balanced
- thye determine the position of the anterior surfaces of the teeth in relation to the buccal mucosa and the portion of the teeth in relation to the ridges of the pts mouth
when is the aesthetics stage?
jaw reg and recording occlusion stage
- ensures that anterior aesthetics are correctly identified
what aspects aer we looking for when recording occlusion ?
- naso-labial angle 90-110 degrees
- incised show at rest
- smile line
- anterior occlusal plane
- prosterior occlusal plane
- midline
- canine line
what do pts complain about in terms of anterior teeth position?
- not enough teeth shown or too much
- teeth too far forward/ backward
- need to spend time in jaw reg stage to identify where teeth need to be halved in terms of lips and ridge
what is alma gauge ?
can be used to measure the distance of incised edges of the teeth from the incisive papilla
can be used to compare occlusal rim inclination with the inclination of teeth on a previous statisfactory denture
having this measurement is useful if pt is happy with the aesthetics of prev denture
what is the smile line stage ?
- need to show them where teeth will be positioned can be done in wax try in
- some pts want to show more teeth than others
- older pt = less teeth shown
- need to verify smile line before try in stage
what happens when lower occlusal plane is too high ?
- results in instability and poor retention
- need to assess in pts mouth
- need to modify so occlusal plane sits below the tongue
where should the tongue rest ?
above occlusal plane to improve the stability an retention
what type of occlusion are we aiming for in a denture ?
bilateral balanced occlusion : the ideal interdigiation of the teeth, in which there’s no cuspal interference in any position of jaw closure - a static situation
what is balanced articulation ?
the ideal interdigitation of the teeth, in which there are no cuspal interferences, when the jaw is moved from side to side - a dynamic situation
how can bilateral balanced occlusion and articulation be achieved in lower arch ?
- positioning teeth correctly in lab
- tech then mounts your models on articulator
- lower teeth (central fossa) need to be positioned in the centre of ridge
how can bilateral balanced occlusion and articulation be achieved in upper arch ?
palatal cups of premolars and molars need to be exactly on ridge
if their position more palatal or more buccal = unstable, reduced support as teeth don’t have support which is usually in centre of ridge
what will improve the stability of the dentures during function?
when LHS and RHS teeth are in contact during lateral movements
what do we want to achieve in bi lateral balanced occlusion ?
all teeth are in contact and uniform and even in both RHS LHS
what are the different aspects of aesthetics in dentures?
- shape, position and colour of teeth
- gums showing or not
- ask pt to bring photo of when they had teeth or what they want the position to be like eg. old denture
- look at smile line
what are the pt related factors not related to their dentures?
- bone
- severely resorbed ridges
- mucosa
- reduced saliva
- gagging
- fractured dentures
what are some bone issues?
- more resorption = more complex construction of the denture, challenging for pt to tolerate
- pts may present with pain thats related to anatomy ie severely resorbed lower ridge = mental foramen is closer to crest of ridge = electric shock = limited clinical solution
- prominences, tori and undercuts
what can we do when faced with severely resorbed ridge s?
- close fitting special tray
- neutral zone impression technique
- consider implant supported dentures
what is the neutral zone technique ?
- captures the dead space between the pts functional and supporting tissues
- impression taken in whilst pt is asked to sip like drinking or counting to help get functional shape
- the lab will convert the record into a wax rim by creating palatal and lingual contours that are functionally captured
how do we asses shallow mental foramen?
- palpate that area = see if there’s any pain
- do this step before taking impressions
- if identified = use soft reline material to reduce pressure on mental nerve
what is a tori?
- bony protrusions that constitute normal anatomy
- can affect the palate (theyre often present in midline) or mandible (often present symmetrically affecting lingual alveolus)
- soft tissues overlying tori are often healthy but may present with areas of displaceable mucosa overlying bony prominences or undercuts
- its important to examine for signs of inflammation, ulceration or overgrowth over Toris which may lead to denture trauma or stomatitis
- these problems should be managed before taking secondary impression
how do we manage Toris ?
- provide relief over Toris if there are concerns that morphology may result in trauma to the overlying tissues = often the case if presented with large tories =
- if minor tori= incorporate them in the design of the denture if it can provide useful undercuts for the dentures retention
- need to communicate this with lab if we want to cover them to provide relief or include them in the design
what is the problem with atrophic mucosa?
- further resorption = less keratinised mucosa = more thin overlying mucosa = will be prone to trauma = will have lower pain threshold for those areas
what are the problems with fibrous flabby ridges?
- not good when it comes to support
- when pt bite together the flabby ridge will be compressed which will result in denture instability
what is the windowed technique ?
- management of flabby ridge to ensure good retention and stability around that area
- special tray is constructed from study model, with a window over the flabby ridge
- this window is created over the special tray
- you perform border moulding
- then you record denture bearing area thats not fibrous using definitive impression eg. medium bodied
- then you record the flabby area by recording with light bodied material through the window
- because we are using light body its less likely to displace that ridge therefore you record in static manner = which will be captured in the cast an din turn captured in the fitting surface of the denture = so when denture is fitted its not going to displace the fibrous ridge
what is the selectively displacement impression technique ?
- another technique in capturing the flabby ridge
- this technique selectively displaces the tissues
- in this case we will be placing minimal pressure
on flabby ridge anteriorly with light body wash and medium body posteriorly - want to perforate tray to prevent displacement of tissues
- border moulding before impression then move onto medium body then light
what are the common causes of reduced saliva >?
- polypharamcy
- auto immune
- poorly controlled diabetes
- H and N radiotherapy
- smoking
- mouth breathing
- anxiety and depression
what problems do pts with reduced saliva flow have ?
- sore areas
- reduced retention and stability
- increased risk of irritation and soft tissue trauma
- increased risk of denture stomatitis
what are some local measures to help with reduced saliva flow?
- sip water freq thru out day
- saliva substitute
- lozenges
- denture adhesives
what are some systemic measures to help with reduced saliva flow?
tx of underlying disease
how do we deal with pts with mild - mod gag reflex ?
reduce post dam
- prescribe multiple post dams to lab
how do we deal with severe gag reflex?
fabricate acrylic training palate to wear for a few months prior to denture construction
- its very thin, multiple post dam, no teeth
- trains them to adapt
what could be reasons for fractures ?
- identify root cause
- pt dexterity
- parafunctional habit
- denture care
- thinness of denture
how do we deal with fractures?
- can be repaired in lab if both surfaces can be put back together
- consider high impact acrylic base if repetitive fracture
- metal mesh strengthen can also be used but will increase the weight and thickness of the denture
dentist pt relationship
