Removable Partial Dentures Flashcards
What is an abutment
any tooth or implant that supports a dental prosthesis
What is a retainer
the portion of a partial denture that attaches the prosthesis to the abutment
What is an extracoronal retainer, and what are the two parts
two metal clasps that lie on the external surface of the abutment
retentive clasp and reciprocal clasp
What is a retentive clasp
the portion of an extracoronal retainer that is located in an undercut area of the crown and resists occlusal or incisal displacement of the RPD
What is the reciprocal clasp
the portion of the extracoronal retainer that is located in a non-undercut area on the opposite side of the abutment and acts as the stabilizing element
What is an intracoronal retainer
when the retainer is contained completely within the contours of the clinical crown. (rare, need two specially designed crowns)
What is a tooth supported RPD
an RPD that receives support from teeth at each end of the edentulous space
how much support does a tooth supported RPD get from the ridge
some, but not a significant amount.
What is another name for a tooth-tissue supported RPD
an extension base
what is a tooth-tissue supported RPD
an RPD with teeth supporting only one end of the edentulous space. they have a mesial or distal extension
What is retention
resistance to displacement away from the teeth and soft tissues
what is support
resistance to displacement toward the teeth and soft tissues
what is stability
resistance to displacement in the mediolateral or anterioposterior direction
Which type of kennedy classification is most common, which is least
1 is most common (then 2, then 3) 4 is least common
What is a kennedy class 1
bilateral edentulous areas posterior to remaining teeth
What is a kennedy class 2
unilateral edentulous area posterior to remaining teeth
What is a kennedy class 3
unilateral edentulous area with teeth both anterior and posterior to it
What is a kennedy class 4
single, bilateral edentulous area that is anterior to remaining teeth, and crosses the midline
in the classification of an edentulous space should classification follow or precede all planned extractions?
it should follow all extractions
would a missing third molar that isn’t going to be replaced be considered when assigning a kennedy classification
nope
would a missing second molar that isn’t going to be replaced be considered when assigning a kennedy classification
nope
would an existing third molar that is going to be used as an abutment for the RPD be considered when assigning a kennedy classification
yes
when you have multiple edentulous areas in an arch, which one is used to determine the classification
the most posterior edentulous area
what do you refer to all edentulous areas that aren’t determining the kennedy classification as
modification spaces
what determines the number of modification spaces you have
the number of additional (not including the classification determining edentulous area) edentulous areas you have. not the number of teeth that are missing.
can there be Kennedy class IV arches with modification spaces
nope.
When should RPDs be planned and designed
from the very beginning, during initial diagnosis and treatment planning
how could diabetes affect an RPD
when it is uncontrolled it can lead to small oral abscesses and poor tissue tone
how could arthritis affect an RPD
it can cause changes in the TMJ which creates difficulties in recording jaw relations
how could paget disease affect an RPD
causes enlargement of maxillary tuberosities
how can acromegaly affect an RPD
it causes an enlargement of the mandible
how can parkinsons affect an RPD
it makes it very difficult for the patient to remove it and insert it, and keep it clean
how can pemphigous vulgaris affect an RPD
causes bullae in the oral cavity, which cause discomfort, dryness, and an ill-fitting denture
how can epilepsy affect an RPD
seizures can cause a fracture in the RPD or loss of additional teeth
how can cancer affect an RPD
radiation/chemo can cause mucosal irritations, xerostomia, infections
how can antihypertensive agents affect an RPD
syncope (orthostatic hypotension)
how can endocrine therapy affect an RPD
cause xerostomia
what is the most important thing to do in a patient interview
listen
what should you do in the first five minutes of an interview
establish rapport
what should we be concerned about a patients expectations
we should make sure that they are realistic, and that they understand the increased maintenance that comes with an RPD. if they have unrealistic expectations, or won’t tolerate the increased maintenance required, treatment shouldn’t be done
What must we understand about a patient with highly mobile lips (gummy smile)
that it can be difficult to achieve good aesthetics with an RPD for this patient
what is a philosophical patient like
they are easy to treat, accept responsibility, and understand they have a role in their health
what is an exacting patient like
well dressed, wants perfection, difficult to treat, once satisfied they are enthusiastic supporters
what is a hysterical patient like
complain without reason, don’t accept responsibility, and have poor success unless they have a change of attitude
what is an indifferent patient like
they ignore instructions, uncooperative, don’t care about remaining teeth, poor prognosis
What is tooth mobility 1
trauma from occlusion, can be reversed with occlusion correction
what is tooth mobility 2
inflammation of PDL, can be reversed if inflammation is eliminated
what is tooth mobility 3
bone loss, non-reversable
what is the necessary crown-root ratio for an abutment tooth
at most 1:1 crown (clinical crown) to root ratio.
if greater than that it is not suitable to be an abutment
what are the options for a tooth with greater than 1:1 crown to root ratio
- Extraction (if the adjacent tooth is capable of being an abutment)
- Splint (usually weakens the strong tooth)
- retained as an overdenture (needs to be endo treated)
What should be done when considering and RPD for a patient with signs of gingivitis and periodontal disease
the disease must be controlled for the RPD to be successful
What do we focus on when observing radiographs during RPD design and planning
the abutment teeth and residual ridge areas
do all root tips need to be removed before RPD placement
no
can 3rd molars be used as abutment teeth
yes
What are favorable and unfavorable root and bone conditions for abutment teeth
large and long roots are favorable (as long as they have a good crown to root ratio)
short conical roots are unfavorable
roots in close proximity to other roots are unfavorable due to less interproximal bone
what does a widened PDL on a potential abutment tooth indicate, and what does it mean for RPD planning
it indicates mobility, trauma, or heavy occlusion
in RPD planning effort should be made to reduce heavy forces on the tooth because additional stress may lead to severe damage
Should you initiate restorative treatment prior to the completion of the diagnostic mounting and design of the RPD
no, unless it is urgent
can you use endodontically treated teeth as abutments
yes you can, but they should be carefully evaluated since they can become more brittle. (they will need a full coverage crown)
What is torus palatinus, and how does it usually affect an RPD
it is tori (bony protuberance) on the hard palate. it usually doesn’t affect an RPD and thus doesn’t have to be removed.
What is torus mandibularis and how does it usually affect an RPD
it is tori (bony protuberance) on the lingual surface of the mandible, it causes uncomfortable fitting of the RPD and usually needs to be removed
What are Exostoses and how do they usually affect RPDs
they are bony overgrowths on an osseus surface. they are more common in the maxilla, can be caused by an extraction, and need to be removed if they are large enough to interfere with RPD seating
What are the options for treating a hard tissue undercut
- reducing the length of the denture base
2. surgically correcting the undercut
when would you surgically correct a hard tissue undercut instead of reducing the length of the denture base
- when reducing the length leads to reduction in stability or support
- when the undercut creates a food impaction
- when shortening the denture base causes an aesthetic issue
what are the treatment options for a frenum that interferes with an RPD
a notch can be placed in the RPD for the frenum, if the notch is unaesthetic (sometimes due to a short lip, or highly mobile lip) then a frenectomy may be indicated
What does the active floor of the mouth refer to
the portion of the floor of the mouth that is mobile. it is important because your RPD cannot rest on the active floor of the mouth. Thus you must measure when the active floor of the mouth is.
for a Kennedy class 1, how many direct retention and indirect retention seats do you need
2 direct and 2 indirect
for a Kennedy class 2, how many direct retention and indirect retention seats do you need
3 direct and 1 indirect
for a Kennedy class 3, how many direct retention and indirect retention seats do you need
4 direct and 0 indirect
for a Kennedy class 4, how many direct retention and indirect retention seats do you need
4 direct and 2 indirect
What is the order of most preferable clasp type to least preferable clasp type for a distal extension
- I-bar
- T-bar
- Wrought Wire
What is the undercut amount needed for an I bar
.01 inch
what is the undercut amount needed for a T bar
.01 inch
what is the undercut amount needed for a wrought wire
.02 inch
where is the mesiodistal location of the I bar
mid-buccal
where is the mesiodistal location of the T bar
distobuccal
where is the mesiodistal location of the WW (wrought wire)
mesiobuccal
What clasps are usually used in Kennedy class III situations
C-Clasps (circlet)
What is a ball clasp and when is it used
it is a clasp with a ball on it that goes over the marginal ridge and engages in the interproximal (facial) undercut. They are used on interim RPDs when lingual interproximal undercuts don’t have sufficient undercuts
