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92 Cards in this Set
- Front
- Back
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What was the % of edentulous patients in the Adult dental surverys of 1968 and 1998?
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1968 - 37%
1998 - 13% |
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What are the two types of complete dentures?
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1. Conventional dentures
2. Copy / Replicate / Duplicate dentures |
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What are possible causes of looseness?
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- lack of retention
- lack of stability - occlusal discrepancies |
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Define the following:
-retention - stability - occlusion - articulation |
Retention - resistance to forces that pull dentures away from the tissues (masticatory and gravity)
Stability - resistance to denture being pushed into the ridge Occlusion - a static phenomenon where opposing teeth are in contact Articulation - when teeth meet during excursive movements of the mandible. |
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What is balanced occlusion and balanced articulation
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Balanced occlusion - a static phenomenon where simultaneous contacts between opposing teeth on both sides of dental arches.
Balanced articulation - dynamic situation where bilateral simultaneous contacts of opposing teeth as mandible moves into and out of ICP. |
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What two main things are involved in the extra-oral examination?
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Skeletal pattern
existing fws |
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Which system is used to classify edentulous ridges?
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Howell and Cawood
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Howell and Cawood: what is a class 1?
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dentate ridge
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What class is a knife edge ridge?
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Class 4
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Howell and Cawood: what is class 5?
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Atrophic ridge
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What class is a recently extracted ridge?
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Class 2
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Howell and Cawood: what is class 3?
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Well formed ridge
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Which surfaces of the existing denture do you examine out of the mouth?
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Polished surface
Impression (Fitting) surface Occlusal surface |
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What should you examine on the existing denture in the mouth?
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Fit (adaptability)
Retention Stability Peripheries Occlusion articulation Aesthetics |
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What is fit (adaptation)?
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Intimate adaptation of the denture baseplate to the tissues.
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How do you check retention?
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By pulling the denture vertically downwards.
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To check stability?
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Rotate in horizontal plane
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Is the quality of the first impression important?
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Yes it is coz it affects accuracy of the special tray which affects accuracy of the working impression which dictates the accuracy of the fit of the final denture.
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What materials are stock trays made from?
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Metal
Polystyrene |
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What materials can be used for periphery modification of stock trays?
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Tracing compound
Wax |
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What modifications may need to be made for a stock tray?
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periphery modification
palate modification |
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Which materials can be used to record a preliminary impression?
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Impression compound
Alginate silicone putty compound with alginate wash |
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Why is an indelible line scribed 1-2 mm short of the sulcus reflection?
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To denote customised tray extensions
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Which landmarks need to be recorded by the upper impression?
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Maxilllary tuberosities
Hamular notch Vibrating line |
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Which landmarks need to be recorded by the lower impression?
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Retromolar pads
distolingual extension mylohyoid ridge |
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What is the aim of the working impression?
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To record the full dba and the full functional width and depth of the sulcus (for optimal denture fit and retention)
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Which are the two most important stages of complete denture construction?
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Working impression
Registration |
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Spacing for upper tray using alginate?
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3 mm
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Why is a close-fitting tray used for the lower impression?
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Lower ridge is normally atrophic and has no undercuts.
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Which materials are used for impressions using close-fitting tray?
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ZOE
medium bodied silicone |
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Where are finger rests on customised lower trays ideal?
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Premolar region
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Why is border moulding done?
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to record functional sulci
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Which are common areas of underextension of upper denture?
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tuberosities
hamular notch |
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Which are common areas of underextension of lower denture?
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retromolar pads
distolingual extensions |
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Which are common areas of overextension of upper denture?
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upper anterior
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Which are common areas of overextension in the lower impression?
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lower mentalis region
buccal shelf |
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Why is underextension of working impression bad?
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No border seal
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Why is overextension of working impression bad?
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Denture will impinge on the elastic muscles and will be displaced when muscle recoil
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What is muscle trimming used for?
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to record dynamic structures such as fraeni
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What distance is a line scribed beyond the sulcus to prevent working-cast overtrimming?
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2-3mm
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What is the effect of overtrimming the working cast?
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loss of border seal in baseplate
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If retention in upper is a problem, what material can be used for the baseplate?
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heat cured baseplate
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Which stage are many errors made in complete denture construction?
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registration
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If existing dentures are present, what is the starting point for obtaining FWS?
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record OVD (occlusal vertical dimension) - upper and lower jaws in occlusion
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Which three methods of measuring OVD?
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1. Ruler
2. Willis Gauge 3. Calipers (two dot technique) |
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if no existing denture is present, what is the starting point for getting FWS?
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RFS (resting face height) or resting vertical dimension - measured with lower denture in the mouth
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What can you say to a patient when recording RFH?
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'lick your lips'
'swallow' 'let your jaw go floppy' |
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What is the equation for calculating FWS?
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FWS = RFH - OVD
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What is the ideal FWS?
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2-4mm
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what is icp?
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the vertical and horizontal position of the mandible in which maximum occlusal contact occurs.
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In which cases is OVD decreased i.e FWS increased?
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Mouth full of teeth
teeth clatter generalised pain over ridges |
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In which cases is OVD increased i.e. FWS decreased?
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Worn occlusal surfaces
Cannot chew properly. |
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What percentage of the population is a Class III? (Skeletal relationship?
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10 %
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What tray would you use for a fibrous flabby ridge?
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windowed customised tray
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During registration, what are the requirements of the baseplates?
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Fit
Rigidity Stability Retention |
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What materials are used to make baseplates for registration rims?
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Light or heat cured acrylic
Shellac |
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Which denture gives most of the aesthetism?
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The upper denture
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Which part of the denture does the width of the registration rim represent?
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The width of the teeth
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In the upper, when the patient opens their mouth, the buccal aspect of the posterior upper block should be just touching what to be in the neutral zone?
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The buccal mucosa
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Which guide line is the anteroposterior guide for the upper record?
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alatragal line
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Which guide is the horizontal guide for the upper record?
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interpupillary line
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Which occlusal plane guide is used to avoid slopes to c/c dentures?
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Fox's occlusal plane guide
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Which denture is mainly for function?
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Lower denture
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What is key for the lower record rim?
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Stability
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To be in the neutral zone what structures must the lower denture be in harmony with both anteriorly and posteriorly?
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Anterior - must accommodate mentalis muscle
Posterior - must give tongue space (rim to touch buccal mucosa as in upper) |
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What can be done to create tongue space in the posterior?
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leave off 7s or 6s.
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Which check lines should be on the registration rim?
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Smile line
Canine line Centre line |
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What is important when selecting teeth for the posterior region?
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Mould (narrow mould is useful. Often leave off 7s and sometimes leave off lingual cusps of 6s)
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Is the balanced articulation with dentures the same as most natural dentitions?
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It is not the same
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Which method is used to correct for occlusal errors?
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Split cast method
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Which method can be used for adjustment of occlusion on an articulator?
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Check record
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Where can the check record technique be done?
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Laboratory
at chairside , using a modified articulator |
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What is balanced occlusion?
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A static state where there are simultaneous contacts between opposing teeth on both sides of the dental arches.
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What is balanced articulation
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dynamic situation where there are bilateral simulatenous contacts between opposing teeth as the mandible moves in and out of the ICP.
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What is the split cast technique and what is it used for?
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Processed dentures , still on casts, are remounted on an articulator in exactly the same jaw relationship . It is used to check for laboratory errors esp an increase in OVD which is shown by the incisal pin failing to contact with the incisal table.
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Name the four types of articulators
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Simple hinge
Fixed average semi adjustable fully adjustable |
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Trial dentures' intraoral examination 'seperately', what to check?
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Fit (adaptability)
Extensions Support Retention Stability neutral zone aesthetics |
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Trial dentures' intra-oral examination 'together'?
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articulation
occlusion aesthetics |
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Fitting, before patient enters the surgery what do you check?
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Impression surface
Polished surface Occlusal surface |
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At which stage is the post dam denoted?
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Trial denture stage
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What are the common problems ar fitting?
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overextension
underextension occlusion (laboratory occlusal errors) articulation |
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Which immersion solution is recommended for cleaning dentures?
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Sodium hypochlorite
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What are the most common complaints for complete dentures?
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Pain
Looseness |
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What 3 pathological probs can present with a complete denture?
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Trauma
Denture induced stomatitis Denture induced hyperplasia (Denture fixative) |
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Which technique is useful in the ageing population?
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Copy technique
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What is the modiolus?
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The point of meeting of 5 facial muscles.
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Which muscles meet at the modiolus?
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Buccinator
orbicularis oris zygomaticus major upper incisive lower incisive levator anguli oris depressor anguli oris |
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What would overextension of the lingual flanges of the lower denture cause?
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Rebounding of the denture due to elastic recoil of the muscles
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How do you get border seal?
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By recording full width and depth of functional sulci.
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How far up the retromolar pads should a denture go?
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half to two thirds way of pear shaped pads.
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What causes denture stomatitis?
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Candida albicans
Wearing dentures at night Poor hygiene |
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Where are the buccal shelves?
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Buccal aspect of lower 5 and 6
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