Prosthodontics Flashcards
What are the indications for replacement of missing teeth?
to improve masticatory efficiency to improve speech preserve or improve oral health by preventing movement of teeth improve distribution of occlusal loads space maintenance restore aesthetics prepare patient for complete denture
What are the treatment options for replacement of missing teeth?
No replacement bridges (resin retained, conventional) implant supported prosthesis removable partial dentures complete immediate denture complete dentures
What are the components of a bridge?
Bridge - prosthodontic appliance definitively attached to remaining teeth and replaces the missing tooth/teeth
abutment - tooth providing support for bridge
retainer - component cemented on to abutment to provide retention. can be full/ 3quarter covereage crown, post retained, onlay, inlay
pontic - artificial tooth suspended from abutments
connector - component joining pontic to retainer
saddle - area of edentulous ridge
units - pontics + retainers
retention - prevents removal along path of insertion
support - ability to bear occlusal load
resistance - prevents dislodgement in apical or oblique directions
What are the different types of bridge?
Fixed - Fixed
fixed - movable
direct - cantilever (one end only)
resin bonded
removable
What are reasons for a bridge failing?
loss of retention, mechanical failure, problems with abutments.
What are classifications of edentulous ridges?
Kennedy I - bilateral free end saddle
II - unilateral free end saddle
III - unilateral bounded saddle
IV - unilateral bounder saddle which crosses the midline only
classes I-III can have modifications. classify by most posterior saddle only
What are the steps involved in designing partial dentures?
Outline saddles plan support obtain retention assess bracing choose connector
What are the laboratory stages in designing a denture?
primary impressions and occlusion -> special trays (design, survey and tooth preparation) Master impressions ->tooth trial (take shade and mould) try in CoCr frame Wax try in delivery
With complete dentures - what is retention and what is it dependent on?
resistance of displacement. dependent on peripheral seal contact area between denture and tissues close fit viscosity and volume of saliva
With complete dentures - what is stability and what is it dependent on?
ability of the denture to resist displacing forces during function. supporting tissues and the forces acting on the polished and occlusal surfaaces
What is the neutral zone?
where muscular displacing forces are in balanced. the ideal zone for the denture to be placed
List three special impression techniques and when they are used
neutral zone impression techniques - when patients have limited natural retention for full lower
flabby ridge technique when patient has compressible ridge on upper anteriors - common when edentulous upper and natural lower
functional impression - tissue conditioner is placed on pt dentures, and they wear their dentures for several days
how do you modify wax rims and record occlusion?
trim rim to give correct naso-labial angle
trim anterior to give correct height regarding lip line
trim occlusal plane - parallel to ala-tragus line
mark centre line, canine line and smile line
What denture hygiene advice would you give a patient?
remove dentures at night and store in water
clean after every meal with a toothbrush and soap over a full sink
once a week use denture cleaner
What are common denture complaints and what are they caused by?
pain - can be roughness, poor OVD, occlusion problems, pathology, RR, exposed foramin
Loose - poor peripheral extension, teeth not in neutral zone, unbalanced articulation, inadequate saliva, poor ridge form, cant adapt
burning mouth - sensitivity to acrylic, candidiasis, xerostomia, psychological conditions
speech - (f and v - incisors palatally placed), (dst - incorrect OJ and OB), (s becomes th - palate too thick), (whistling - palatal vault too high), clicking - OVD or poor retention
cheek biting - teeth not in neutral zone
retching
recurrent # - carelessness, occlusal faults, fatigue, flexing of denture from tori
What is denture stomatitis and how do you manage it?
it is a common condition associated with candida albicans infection. Appears as redness under the denture bearing area. increased in incidence if you have f/f, F>M
generally caused by poor denture hygiene and wearing dentures over night. systemic problems can predispose - haematinic deficiencies, diabetes, steroids, drugs, xerostomia, high sugar intake
Manage with good denture hygiene, mechanical and chemical cleaning - can use stearadent. modify aetiological factors.
miconazole gel to fitting surface
When would you provide a copy denture?
cant adapt
changing the worn occlusion when fit surface is good
denture has been bleached/discoloured but rest is good
pt wants a spare
When would you provide an over denture?
-/F or free end saddles so increase stability and reduce retention
CLP
hypodontia
severe tooth wear
What is osseointegration?
A direct functional and structural connection between a load carrying titanium implant with the cone with no intervening CT
Why is tooth support useful in a partial denture?
under load the compressible tissues can move 500um under 4 newtons, whereas teeth move 20um - significantly less compression of the tissues, less movement and increased comfort
How would you design a rest seat on a tooth?
Rest seat must be able to direct foce down long axis of tooth
basin shaped to allow some rotation
deep enough to allow for metal to not interfere with occlusion - 0.5mm on occlusal surface, 1mm reduction in marginal ridge
What features of an RPD give indirect retention?
the incisal rests which are 90 degrees to clasp axis
what major connector would you use for a lower RPD and why?
lingual bar, CoCr.
material offers retention and stability
well tolerated
free of gingival margins
17 y/o with congenitally missing 22/23. what options for treatment are there?
implants RPD bridge (4 units, fixed/fixed) ortho combined ortho and restorative
What would a dentist check before referral to an implantologist?
smoking status periodontal disease diabetes osteoporosis/BP use blood disorders
What does an implantologist check locally for suitability?
quality of bone quantitiy of bone position of existing teeth root placement oral hygeine
List Atwoods classification of edentulous ridges
I - pre extraction II - post extraction III - high and well rounded IV - knife edge V - low and well rounded VI - depressed
How would you modify a lower denture for a patient with an unerupted tooth causing problems so that it was stable and comfortable in function
soft lining balanced articulation polished surface shape and base shape correct extension onto non-resorbable tissues and retromylohyoid area correct OVD
What is an RPI system and when is it used?
it is an occlusal rest, a proximal plate and a gingivally apprioaching I bar clasp
as the denture sinks into saddle, rotation around mesial rest, distal plate and i bar rotate down and mesially, disengage, avoid torquing forces
What factors of the denture provide stability?
direct and indirect retention, bracing, strong connector, even distribution of rests
What problems can occur from increased OVD?
clicking when talking whistling problems speaking difficulty eating pain
What problems can occur from decreased OVD
poor facial profile
facial discomfort
problems chewing
list 3 different ways you can measure the OVD
willis gauge
calipers/ ruler to two places which dont move
swallowing
how do you test a dentures retention?
move cheeks out the way and see how it moves
tip anterior segment forward
pull anterior teeth
What is combination syndrome?
edentulous maxilla
dentate mand anterior portion
get resorption of the bone - hypertrophic and atrophic changes. ends up with flabby fibrous tissue deposited max ant
What are the management options for a knife edge ridge?
check for sore points on ridge by pressing
cut relief in impression and take mucostatic impression there (light body PVS)
soft lining on knife edge
surgery to smooth
What are the benefits of a shortened dental arch?
good occlusal stability good functionality aesthetic cost efficient easier to maintain
what are contraindications for SDA?
remaining teeth arent in favourable occlusion
TMJ
significant malocclusion
restorations required in the 20 teeth to be used
What are the choices for a lower major connection and when are they used?
lingual bar: 8mm of space (3mm FGM, 4mm bar, 1mm from sulcus). need good OH and perio support
lingual plate: if no space for bar. may cause perio problems
Dental bar: less used
what is indirect retention?
resistance to vertical displacement by counteracting the axis of rotation provided by direct retention
What is the difference between a soft lining on a denture and a tissue conditioner?
a soft lining is used in tissue health as a reline or shock absorber. a tissue conditioner is used in poor tissue health - candida or ulcers to aid healing and dissipate forces - short term option
What features of complete dentures do you check at try in?
extension, retention, stability, aesthetics, OVD, occlusion, teeth position, patient thoughts
What are the extensions for upper and lower dentures?
upper: hamular notch to hamular notch, along vibrating line
lower - 2/3 up retromolar pad
What aspects make up the shade of a tooth?
hue, chroma, value, translucency
