PROS MIDTERM STUDY QUESTIONS
PROS MIDTERM STUDY QUESTIONS
Chapter 2 Clasp-Retained Partial Denture
1. In chronological order of accomplishment, give the six
sequential, correlated phases in treating a partially edentulous
patient with removable prostheses. First phase: Patient education,
patient should be educated thouroughly and understand the tx before
any treatment is decided on or started.
Second phase: diagnosis (Health hx, dental health, etc.),
treatment planning (surveying) , design of the partial denture
framework, treatment sequencing and execution of mouth preparations
(get good support, retention)
Third phase: Provision of adequate support for the distal
extension denture base (not needed for tooth supported partials,
need to make the distal base based on the functional impression /
form (soft tissue shape under function) rather than the anatomic
ridge form)
Fourth phase: establishment and verification of harmonious
occlusal relationships and tooth relationships with occlusal and
remaining natural teeth.
Fifth phase: initial placement procedures, adjustments to
contours and bearing surfaces and to occlusal surfaces. Also,
review patient instructions.
Sixth phase: follou up services, recall appointments
2. If the dentist and the patient share responsibility for the
success of treatment, what must be undertaken to prepare patients
to accept their responsibility?
Inform patient of the benefits of a removable partial
denture
Advise Patients on proper oral care and maintenance
procedures
Educate on use of the prosthesis to avoid misuse
3. Because treatment planning is the sole responsibility of the
dentist, which if any of the following may be omitted as
noncontributory to total treatment: (1) a complete health history,
(2) a history of past dental experiences (3) an oral examination,
(4) a radiographic examination, (5) an evaluation of occlusal
relations of remaining teeth (6) a survey of diagnostic casts, (7)
cost or (8) patient desires?
Neither 7 or 8 are mentioned as parts of the treatment plan.
(see page 14)
4. A specific design of the removable restoration must be
planned before mouth preparation procedures. The dentist
(can-should not) delegate the responsibility for the design to a
dental laboratory technician.
The dentist should not delegate the responsibility for the
design to a dental laboratory technician.
5. Stability in a removable restoration (is is not) desirable to
help maintain the health of oral structures. A tooth supported
restoration usually (can cannot) be made more stable than a
restoration supported by teeth and residual ridges.
Stability in a removable restoration is desirable to help
maintain the health of oral structures.
A tooth supported restoration usually can be made more stable
than a restoration supported by teeth and residual ridges.6. In the
fifth phase of treatment (initial placement of the restorations),
three things are done before the patient is given possession of the
denture(s). Two of these are (1) correction of denture base
contours and occlusal discrepancies that may have resulted form
processing and (2) review of patient education, including
adjustment expectations. What other step must be accomplished
during the appointment?
Ensure that the patient understands the uses of the RPD and how
to care for the denture and soft tissues.
7. What is the purpose of periodic recall of patients treated
with removable partial dentures?
For evaluation of the response of the oral tissues, soft tissue
changes
maintain oral health
evaluation of the acceptance of the prosthesis by the
patient
Evaluate patient oral hygiene
8. What is the one predominant reason why the clasp-type or
partial denture is used more often in most practices than is the
internal attachment type of prosthesis?
Cost
9. Deficiencies in design and fabrication and those related to
patient education are the culprits of limited success in treatment
with removable prostheses. Avoiding these deficiencies will make
the goal of prosthetic dentistry obtainable. This goal is to
______________, ___________, and ______________.
promotion of oral health
restoration of partially edentulous mouths
elimination of the ultimate need for complete dentures
Chapter 3
1. Would you agree that the primary purpose of a classification
is to enhance communication among dentists? Support your
answer?
A: Yes and no. There are several classifications that have been
proposed and the use of it would facilitate communication. In this
book the Kennedy classification is the only one used as a way to
better communication. So the use of classifications for partially
edentulous areas does help communication, but one classification
should be used.
2. Many classification systems have been propsed; however, the
most widely accepted system in the US is the one proposed by
_______________ in 1925.
A: Dr. Edward Kennedy
3. A classification of partially edentulous arches should
satisfy at least three requirements. List them.
A:
It should permit immediate visualization of the type of
partially edentulous arch that is being considered
It should permit immediate differentiation between the tooth
supported and the tooth and tissue supported removable partial
denture
It should be universally acceptable
4. Kennedy divided al partially edentulous arches into _______
main types.
A: 4
5. What is meant by modification space?
A: Edentulous areas in an arch that are variations to the basic
4 classifications. Edentulous areas other than those determining
the classification.
6. Which two classes of partially edentulous arches have the
greatest incidence of occurrence according to Skinner?
A: Skinner classification type III
7. Dr. O.C. Applegate contributed greatly to the application of
the original Kennedy classification system. What was this
contribution?
A: He contributed eight rules governing the application of the
Kennedy method
8. Classify the partially edentulous arches illustrated in
Figure 3-3 (p. 23)
A. Kennedy Class IV
B. Kennedy class I
C. Kennedy class II
D. Kennedy Class III
E. Kennedy Class III
F. Kennedy Class III
G. Kennedy Class IV
H. Kennedy Class II
I. Kennedy Class III
Note: Kennedy Classification
I Bilateral edentulous areas located posterior to the natural
teeth
II A unilateral edentulous area located posterior to the
remaining natural teeth
III A unilateral edentulous area with natural teeth remaining
both anterior and posterior to it.
III A single, but bilateral (crossing the midline), edentulous
area located anterior to the remaining natural teeth
Chapter 4:
1. What elements prevent movement of the base(s) of a
tooth-supported denture toward the basal seats? This movement is
primarily prevented by rests on abutment teeth and to some degree
by any rigid portion of the framework located occlusal to the
height of contour. (Intracoronal rest use is permissible in a
tooth-supported denture to provide occlusal as well as horizontal
stabilization.)
2. Movement of a distal extension base away from basal seats
will occur as a rotation movement or as horizontal movement.
3. What is the difference between fulcrum line and axis of
rotation?
A: Fulcrum line is a specific type of axis of rotation. Rotation
about an axis through the most posterior abutments. Fulcrum line is
the center of rotation as the distal extension base moves toward
the supporting tissue when an occlusal load is applied. This axis
may be through occlusal rests or any other rigid portion of a
direct retainer assembly located occlusally or incisally to the
height of contour of the primary abutments.
4. Identify the fulcrum line on a Class I arch; Class II,
modification 1; and a Class IV.
A: Page 31, fig 4-7 shows Class II, modification 1
5. In the treatment planning and design phase of partial denture
service, the functional movements of RPD's should be considered
when designing the individual __________ ___________ of the
prosthesis. ( 2 words)
A: component parts
6. Forces are transmitted to abutment teeth and residual ridges
by RPD's. One of the factors of a force is its magnitude. List the
other three factors of a force that a dentist must consider in
designing RPDs.
A: Factors to consider with a force: direction, duration,
frequency, magnitude
7. The design of a removable restoration necessitates
consideration of mechanics and biological considerations. True or
False?
A: True
8. Of the simple machines, which two are more likely to be
encountered in the design of RPD's?
A: The lever and inclined plane.
9. What is a lever? A cantilever?
A: A lever is a rigid bar supported somewhere along its length.
The support point of a lever is the fulcrum. A cantilever is a beam
supported at one end and can act as a first-class lever.
10. Name the three classes of levers and give an example of
each.
A: Classification of levers is based on location of the fulcrum
(can be a tooth surface such as an occlusal rest), resistance
(provided by a direct retainer or a guide plane surface), and
direction of effort force (force of occlusion or gravity). For a
visual depiction of first, second, and third class levers, see page
28, Fig.4-2.
First class: Teeter-totter
Second class: Wheelbarrow
Third class: Fishing pole
11. Of the three classes of lever systems, which two are most
likely to be encountered in Removable Partial Prosthodontics? Guess
is first and second class since all three are found in RPDs.
12. Explain how one would figure the mechanical advantage of a
lever system given dimensions of effort and resistance arms.
A: (p. 30) Mechanical advantage = Effort arm Resistance arm
13. What class lever system is most likely to be encountered
with a restoration on a Class II, modification 1 arch when a force
is placed on the extension base?
A: p. 31) First class lever system. See Figure 4-7.
14. What factor permits a distal extension denture to rotate
when the denture base is forced toward the basal seat?
A: (P.31) If tissue support under extension base allows
excessive vertical movement toward the residual ridge. See figure
4-6.
15. Is an abutment tooth better able to resist a force directed
apically or horizontally? Why?
A: Apically. Because more periodontal fibers are activated to
resist vertically directed force than are activated to resist
horizontally (off-vertical) directed force. Horizontal axis of
rotation is located somewhere in root of tooth. See figure 4-9.
Page 32.
16. Where is the location of the horizontal (tipping) axis of an
abutment tooth?
A: Horizontal axis of rotation is located somewhere in root of
tooth.
See Figure 4-9, page 32.
17. Why should components of a direct retainer assembly be
located as close as possible to the tipping axis of a tooth?
A: Forces placed closer to the support reduces the effort arm.
Figure 4-10, page 32. Therefore, placing the components of a direct
retainer assembly as close as possible to the tipping axis of the
tooth reduces the effort arm causing the tipping action of the
tooth.
Chapter 5
1.A Class I removable partial denture should have seven
components. Name the seven components.
major connectors
minor connectors
rests
direct retainers
stabilizing or reciprocal elements (as parts of a clasp
assembly)
indirect retainers (if the prosthesis has distal extension
bases)
one or more bases, each supporting one/several replacement
teeth
2.Define the term major connector in your own words.
the component of the partial denture that connects the parts of
the prosthesis located on one side of the arch with those on the
opposite side
the unit of the partial denture to which all other parts are
directly or indirectly attached
the component provides cross-arch stability to help resist
displacement by functional stresses
3.What are the nine desirable characteristics of major
connectors?
made from an alloy compatible with oral tissue
is rigid and provides cross-arch stability thru the principle of
broad distribution of stresses
does not interfere with and is not irritating to the tongue
does not substantially alter the natural contour of the lingual
surface of the mandibular alveolar ridge or of the palatal
vault
does not impinge on oral tissue when the restoration is placed,
removed, or rotates in function
covers no more tissue than is absolutely necessary
does not contribute to the retention or trapping of food
particles
has support from other elements of the framework to minimize
rotation tendencies in function
contributes to the support of the prosthesis
4.What purposes are served by rigid major connectors as
contrasted with flexible connectors?
it effectively distributes forces throughout the arch and acts
to reduce the
load to any one area while effectively controlling prosthesis
movement
if it were flexible, the ineffectiveness of connected
components
jeopardizes the supporting oral structures and can be a
detriment to the
comfort of the patient, cause damage to abutment teeth, injury
to residual
ridges, or impingement of underlying tissue
5.Major connectors should be located in a favorable relation to
moving tissue, gingival tissue, and areas of bony and tissue
prominences. What difficulties would the patient encounter if the
preceding guidelines are not carried out?
if placed too close to movable tissue, the denture can be
displaced
if it impinges on gingival tissue, it can cut off the blood
supply to the tissue
areas of bony and tissue prominences should be avoided during
placement and removal so as not to damage the tissue or cause pain
(I couldnt find this one in the book)
6.Name and draw the cross-sectional form of the basic mandibular
major connector
the basic form of a mandibular major connector is a half pear
shape located above moving tissue but as far below the gingival
tissue as possible
the superior border of a lingual bar connector should be tapered
toward the gingival tissue superiorly with its greatest bulk at the
inferior border, resulting in a contour that is a half pear
shape
7.Margins of major connectors adjacent to gingival tissue should
be located far enough from the tissue to avoid possible impingement
when the denture rotates from functional and parafunctional forces.
The superior border of a lingual bar should be located how far away
from gingival crevices?
4 mm
8.Describe two methods by which the location of the inferior
border can be accurately determined.
measure the height of the floor of the mouth in relation to the
lingual gingival margins of adjacent teeth with a periodontal
probe. during these measurements, the tip of the patients tongue
should be just lightly touching the vermilion border of the upper
lip. these measurements can then be transferred to the casts
use an individualized impression tray having its lingual borders
3 mm short of the elevated floor of the mouth and then use an
impression material that will permit the impression to be
accurately molded as the patient licks the lips. the inferior
border of the planned major connector can then be located at the
height of the lingual sulcus of the cast of the impression
9.What is meant by the word relief? Rationalize planned relief
for a lingual bar and give quantitative rules of thumb that depend
on the contour of the anterior, lingual alveolar ridge.
relief is space between the lingual bar, lingual plate, or any
place where the framework crosses gingival tissue; and the movable
tissue so that the framework doesnt impinge on the tissue
(I couldnt find the second half of this questions answer)
10.Discuss those clinical observations that indicate the choice
of a lingual bar as a major connector.
if there is sufficient vertical distance between the gingival
tissue of anterior teeth and the floor of the mouth to allow the
superior border of the bar to be a minimum of 4 mm away from the
gingiva and the inferior border to be above the height of the floor
of the mouth then it is indicated
11.What is the form of a mandibular linguoplate major
connector?
the upper border should follow the natural curvature of the
supracingular surfaces of the teeth and should not be located above
the middle third of the lingual surface except to cover the
interproximal spaces to the contact points. the half pear shape of
the lingual bar should still form the inferior border providing the
greatest bulk and rigidity.
basically, if the rectangular space bounded by the lingual bar,
the anterior tooth contacts and cingula, and the bordering minor
connectors is filled in, a linguoplate results
12.Give four clinical observations that indicate use of a
linguoplate rather than a lingual bar as a major connector.
when a lingual frenum is high or the space available for a
lingual bar is limited
in class I situations in which the residual ridges have
undergone excessive vertical resorption. Flat residual ridges offer
little resistance to the horizontal rotational tendencies of a
denture.
for stabilizing periodontally weakened teeth, splinting with a
liguoplate can be of some value when used with definite rests on
sound adjacent teeth
when the future replacement of one or more incisor teeth will be
facilitated by the addition of retention loops to an existing
linguoplate
13.Draw a sagittal section through a cast that shows the basic
form of a linguoplate.
see page 38
14.What is the difference in determining the location of the
inferior borders for lingual bars and linguoplates?
the inferior border of a lingual bar must be located so that it
does not impinge on the tissue in the floor of the mouth because it
changes elevations during the normal activities of chewing and
speaking. the linguoplate inferior border should extend past
gingival crevices and margins and end in an area that is above
movement of the floor of the mouth and in an ideal location that is
comfortable to the patient
15.Describe the superior extent of the apron portion of a
linguoplate in relation to the lingual surfaces of teeth contacted
by the major connector.
it should follow the natural curvature of the supracingular
surfaces of the teeth and should not be located above the middle
third of the lingual surface except to cover interproximal spaces
to the contact points
16.What are the indications for use of a lingual bar-continuous
bar-type of major connector? (see page 39 for a picture of this
type of connector/ 5-5 D)
when a linguoplate is the major connector of choice, but the
axial alignment of the anterior teeth is such that excessive
blockout of interproximal undercuts must be made or when wide
diastemata exist between the lower anterior for better esthetic
results
17.Interpret in your own words the rationale of this statement
made by McCracken: No component of a partial denture should be
added arbitrarily or conventionally. Each component should be added
for a good reason and to serve a definite
purpose.
I didnt answer this one but the quote is on page 42.
18.How may a linguoplate be modified to avoid an over display of
metal when used on an arch in which wide diastemata exist between
anterior teeth?
the linguoplate can then be constructed so that the metal will
not appreciably show through the spaced anterior teeth. see page 43
for an example of this connector. it is called an interrupted
linguoplate
19.The dentist alone is responsible for the design of the
restoration, which is based on both biological and mechanical
principles. Give the dimensional specifications of the wax patterns
of mandibular major connectors.
I have no idea-I emailed Dr. Olin
20.At what point in treating the partially edentulous patient
must the choice of maxillary and mandibular major connectors be
made? Explain.
after considering the diagnostic data and relationg them to the
basic principles of major connectors
the major connectors are what everything else in the partial
denture is connected to and built upon so it should be the first
component of the framework to be designed.
21.There are basically four types of maxillary major connectors.
Name and describe them.
single palatal strap (includes combination anterior/posterior
palatal strap type connectors) = these are single, broad palatal
strap connectors that are a minimum of 8 mm wide
palatal plate = these are any thin, broad, contoured palatal
coverage used as a maxillary major connector and covering one half
or more of the hard palate
U-shaped palatal connector = these are usually very bulky to
maintain rigidity and are the least desirable major maxillary
connector
single palatal bar (includes combination anterior/posterior
palatal bar type connectors) = less than 8 mm in width and
relatively bulky again to maintain rigidity. these are also
undesirable connectors but for some reason are used too often
22.What objections are associated with the use of the single
palatal bar-type major connector?
for a single palatal bar to have the necessary rigidity for
cross-arch distribution of stress, it must have concentrated bulk,
which, unfortunately, is all too often ignored. It is not as
comfortable to the patient. this includes the anterior/posterior
palatal bar connector as well.
23.Which type of palatal major connector is probably the most
rigid and at the same time covers the smallest amount of soft
tissue?
single palatal strap
24.In what situations would one be most likely to use a single
palatal strap-type major connector?
bilateral tooth-supported prostheses, even those with short
edentulous spaces, are effectively connected with a single, broad
palatal strap connector, particularly when the edentulous areas are
located posteriorly.
for reasons of torque and leverage, a single palatal strap major
connector should NOT be used to connect anterior replacements with
distal extension bases
FYI = the combo anterior/posterior palatal strap connector may
be used in almost any maxillary partial denture design (except in
those pts. with large posterior palatal tori)
25.There are definite rules of thumb for the location of the
anterior and posterior borders of all palatal major connectors.
Describe the relationship of the borders to rugae, junction of hard
and soft palates, gingival crevices, pterygomaxillary notches, and
palatal tori.
anterior borders should follow valleys between rugae and stay
parallel to the line made by the rugae and be 6 mm away from the
anterior gingival margins
posterior borders are located just anterior to the soft palate
and no farther posterior than the most posterior teeth
borders should not impinge upon tissue and if they do cover
gingival tissue there should be some relief. also, if a border
needs to cross gingival tissue, it should do so at right angles
ALSO framework borders if possible should be 6 mm away from
gingival margins
pterygomaxillary notches are used as most posterior extension of
the denture base (acrylic portion?)
palatal tori should not be covered by major connector
26.Can adequate support be obtained by resting the palatal major
connector on tooth
inclines? Why?
major connector components resting on unprepared inclined tooth
surfaces can lead to slippage of the denture or to orthodontic
movement of the tooth and eventual impingement of gingival
tissue
27.Rationalize this statement: Either support the connector by
definite rests on the teeth contacted, bridging the gingivae with
adequate relief, or locate the connector far enough away from the
gingivae to avoid any possible restriction of blood supply and
entrapment of food debris.
it already sounds pretty rationalized to me but it sounds like
avoiding impingement of the gingival tissue is a very important
issue when designing the major connector?
this statement can be found on page 46
28.Why should all gingival crossings by components of a
framework be abrupt and at right angles to the major connector and
bridge the gingivae with adequate relief?
a straight line is the shortest distance possible between the
framework crossing the gingivae and the major connector and
therefore less gingival tissue will be covered by the framework
(the book didnt have an answer to this question so this is the best
I could come up with)
relief is once again important so that the tissue isnt
traumatized
29.Describe a continuous bar mandibular major connector and list
the indications for its use.
when a linguoplate is the major connector of choice, but the
axial alignment of the anterior teeth is such that excessive
blockout of interproximal undercuts must be made
I think this basically means that if the teeth are all twisted
funny and you cant get the linguoplate to adapt well to the teeth
because you have to block out so much that theres too much relief
between the teeth and framework that this is the type to use
there is a good example of this type of major connector
discussed in this question and in question 16 on page 45
30.Describe a sublingual bar mandibular major connector and list
the indications for its use.
the bar shape is essentially the same as that of a lingual bar,
but placement is inferior and posterior to the usual placement of a
lingual bar, lying over and parallel to the anterior floor of the
mouth
it is indicated when the height of the floor of the mouth does
not allow placement of the superior border of the bar at least 4 mm
below the free gingival margin
it is generally accepted that a sublingual bar can be used in
lieu of a lingual plate if the lingual frenum does not interfere or
in the presence of an anterior lingual undercut that would require
considerable blockout for a conventional lingual bar
look at page 39 figure 5-5 C for a picture
31.What clinical and diagnostic observations would lead to the
selection of an anterior/posterior palatal strap-type major
connector?
the only condition preventing their use is when there is an
inoperable maxillary torus that extends posteriorly to the soft
palate
it may be used with any Kennedy class of partially edentulous
arch and is used most frequently in classes II and IV
32.Under what circumstances is full palatal coverage, by the
major connector, indicated?
when the last remaining abutment tooth on either side of a class
I arch is the canine or first premolar tooth and when the residual
ridges have undergone excessive vertical resorption
33.Describe a palatal linguoplate major connector and explain
why such a design would be selected.
it is used when residual ridges have undergone extreme vertical
resorption and terminal abutments have suffered some bone loss and
splinting cannot be accomplished
the design is similar to that of the mandibular linguoplate and
the connector rests on rest seats prepared in the canines and
covers the lingual portion of the anterior teeth in the same manner
as the mandibular linguoplate
there is a good picture of this connector on page 50 figure
5-24
34.Describe the five steps outlined by Blatterfein for the
design of palatal major connectors on a diagnostic cast of a Class
I maxillary arch.
step 1 = outline primary bearing areas. primary bearing areas
are those that will be covered by the denture base (see page 51
figure 5-25)
step 2 = outline nonbearing areas. nonbearing areas are the
lingual gingival tissue within 5 to 6 mm of the remaining teeth,
hard areas of the medial palatal raphe (including tori), and
palatal tissue posterior to the vibrating line (the line between
hard and soft palate) (see page 51 figure 5-25)
step 3 = outline connector areas. steps 1 and 2, when completed,
provide an outline or designate areas that are available to place
components of major connectors (page 51 figure 5-25)
step 4 = selection of connector type. selection of the type of
connector is based on four factors: mouth comfort, rigidity,
location of denture bases, and indirect retention. connectors
should be of minimum bulk and should be positioned so that
interference with the tongue during speech and mastication is not
encountered. connectors must have a maximum of rigidity to
distribute stress bilaterally. the double-strap type of major
connector provides the maximum rigidity without bulk and total
tissue coverage. in many instances the choice of a strap type of
major connector is limited by the location of the edentulous ridge
areas. when edentulous areas are located anteriorly, the use of
only a posterior strap is not recommended. by the same token, when
only posterior edentulous areas are present, the use of only an
anterior strap is not recommended. the need for indirect retention
influences the outline of the major connector. provisions must be
made in the major connector so that indirect retainers may be
attached.
step 5 = unification. after selection of the type of major
connector based on the considerations in step 4, the denture base
areas and connectors are joined (page 51 figure 5-25)
35.What is a minor connector?
those components that serve as the connecting link between the
major connector or base of a removable partial denture and the
other components of the prostheses; such as clasp assembly,
indirect retainers, occlusal rests, or cingulum rests
36.What are the functions of minor connectors?
joins denture parts
transfers functional stress to the abutment teeth. this is a
prosthesis-to-abutment function of the minor connector. occlusal
forces applied to the artificial teeth are transmitted through the
base to the underlying ridge tissue if that base is primarily
tissue supported. occlusal forces applied to the artificial teeth
are also transferred to abutment teeth through occlusal rests. the
minor connectors arising from a rigid major connector make possible
this transfer of functional stress throughout the arch
transfers the effect of the retainers, rests, and stabilizing
components throughout the prosthesis. this is an
abutment-to-prosthesis function of the minor connector. thus forces
applied on one portion of the denture may be resisted by other
components placed elsewhere in the arch for that purpose. a
stabilizing component on one side of the arch may be placed to
resist horizontal forces originating on the opposite side. this is
possible only because of the transferring effect of the minor
connector, which supports that stabilizing component, and the
rigidity of the major connector.
37.Should minor connectors be structurally rigid or flexible?
Why?
they should be rigid otherwise the transfer of functional
stresses to the supporting teeth and tissue will not be
efective
38.Describe the shape of a minor connector contacting axial
surfaces of adjacent abutments at interproximal areas.
they should not be located on a convex surface.
they should be located in an embrasure where it will be least
noticeable to the tongue
they should conform to the interdental embrasure, passing
vertically from the major connector so that the gingival crossing
is abrupt and covers as little of the gingival tissue as
possible
they should be thickest toward the lingual surface, tapering
toward the contact area
the deepest part of the interdental embrasure should have been
blocked out to avoid interference during placement and removal, and
to avoid any wedging effect on the contacted teeth
39.Identify six of the minor connectors in this drawing.
the drawing is on page 65.
40.What modification in the deisgn of a minor connector was
suggested by Radfor? What are the suggested advantages and the
disadvantages of this variation in
design? What is the limitation of this design?
the application of this modification was suggested to be limited
to the maxillary arch only (as the lingual cusp is the
nonfunctional cusp and a minor connector traversing over a lingual
cusp and into a rest seat for example would not interfere with
occlusion), with the minor connector located in the center of the
lingual surface of the maxillary abutment tooth
it is suggested that this modification reduces the amount of
gingival tissue coverage, provides enhanced guidance for the
partial denture during insertions and removal, and increases
stabilization against horizontal and rotational forces.
however, because of its location, such a design variation could
encroach on the tongue space and create a greater potential space
for food entrapment.
this variation should be used with careful application
41.Minor connectors used to attach acrylic resin denture bases
to major connectors should be located on both buccal and lingual
sides of the residual ridge. Why?
such an arrangement will not only add strength to the denture
base but also may minimize distortion of the cured base from its
inherent strains caused by processing
it may not be a bad idea for everyone to glance at the purple
section on page 56 for a longer, better explanation of this
also figure 5-36 on page 56 is a good figure to read about
42.State rules of thumb for the form and length of minor
connectors connecting
acrylic resin denture bases to major connectors.
YOU are GOING to HATE me! Sorry but the purple section above
answers this question really well. I will do my best to
summarize
when an artificial tooth will be placed against a proximal minor
connector, the minor connectors greatest bulk should be toward the
lingual aspect of the abutment tooth
remember, those portions of a denture framework by which acrylic
resin denture bases are attached are minor connectors and they
should be completely embedded in the denture base
the junctions of these mandibular minor connectors with the
major connectors should be strong butt-type joints but without lots
of bulk
angles formed at the junctions of the connectors should not be
greater than 90 degrees, thus ensuring the most advantageous and
strongest connection between acrylic denture base and major
connector
43.What advantages accrue to the restoration by having minor
connectors for acrylic resin denture bases attached to the major
connector in a butt-type joint?
these are strong joints and when placed at 90 degree angles it
allows for maximum strength
44.Describe the best location for palatal finishing lines at the
junction of major and minor connectors. How do you determine this
optimum location on a cast? Why is it important that the natural
contour of the palatal vault be restored with a removable
restoration?
they are basically asking about the location of where the
gridwork (which is a minor connector) and the major connector (say
a palatal plate) should meet. just for clarification, the minor
connector will meet the major connector and be thinner than the
major one so that when the acrylic resin covers the minor connector
it will meet up with the major connector at the same plane and the
patient wont feel the transition once placed in the mouth
if the finish line (where the two meet) is located too far
mesially on the ridge, the natural contour of the palate will be
altered by the thickness of the junction and the acrylic resin
supporting the artificial teeth
if the finish line is located too far bucally, it will be most
difficult to create a natural contour of the acrylic resin on the
lingual surface of the artificial teeth
the location of the finishing line at the junction of the major
and minor connector should be based on restoring the natural
palatal shape, taking into consideration the location of the
replacement teeth
figure 5-41 on page 60 is a good picture to clarify this
concept
maintaining palatal vault contour is critical so that the
patient experiences a natural feeling and enhancing speech
AFTER ALL THAT-FIGURE 5-42 ON PAGE 60 EXPLAINS IT ALL! UGH!
45.In addition to a more natural feeling contour, what other
factors may be achieved by the use of anatomic replica patterns for
palatal major connectors?
enhanced speech was all I could find, but I would assume that
mastication and swallowing would be more comfortable if the palate
were more anatomically correct
46.What are three ways to increase the bond strength between the
minor connectors and the acrylic resin denture bases? How much is
the bond strength increased?
answer is not in the chapter. I will email Dr. Olin to get the
correct answer.
Chapter 5 Questions
1) What are the 7 components of a class 1 RPD?
- The major connectors, minor connectors, rests, direct
retainers, stabilizing components, indirect retainer and one or
more bases supporting teeth.
2) What is a major connector?
- supporting connection that unites both sides of the arch.
3) What are 5 characteristics of major connectors?
- Made w/rigid alloy compatible with oral tissue, rigid cross
arch stability, doesnt irritate tongue, doesnt alter lingual
contour, covers only necessary tissue.
4) What is the purpose of a rigid major connector instead of a
flexible connector?
- To prevent distortion of the cross arch dimensions
5) If major connectors are not place off tissue/bone, what could
happen?
- irritation of tissue, periodontal problems.
6) Name and draw the form of a basic mandibular connector?
- SEE BOOK P36
7) The superior border the mandibular major connector should be
located at least _ mm from teeth?
- 4mm
8) How do you measure the inferior border space of a mandibular
major connector?
- Use a perio probe to measure, take and impression and
measure.
9) What is meant by relief?
- Spaced made by placing wax spacer under the connector during
RPD construction to keep denture components off tissue.
10) Discuss clinical choice of a lingual bar as a major
connector.
- SEE BOOK P.39
11) What is the form of a mandibular plate?
- SEE BOOK P.40
12) Give 4 clinical observations that indicate use of a plate
instead of a bar?
- high lingual frenum, class 1 with major ridge resorption,
stabilizing perio teeth, possible future replacement of teeth (can
be added easier).
13) Draw lingual plate?
- SEE BOOK P.40
14) What is the difference in determining inferior borders of a
lingual plate vs. bar?
- undercuts must be blocked out
15) Describe the superior aspect of the apron of a lingual
plate.
- closely adapted to the teeth, extending into non undercut
embrasures.
16) What are the indications for use of a lingual bar continuous
bar type connector?
- when excessive block out of mandibular teeth are needed to
place plate, a cingulum bar may be used.
17) Not necessary (SEE BOOK)
18) How may a lingual plate be modified to prevent display of
metal in an embrasure?
- The major connector can be constructed so that the metal is
cut out of embrasure areas (SEE BOOK P.43)
19) Give the dimensional specifications of the wax patterns of
mandibular major connectors.
- SEE BOOK P64
20) At what point in treating the partially edentulous patient
must the choice of maxillary and mandibular connectors be made?
- During design
21) 4 types of maxillary connectors
- palatal strap
- single broad palatal connector
- anterior posterior strap
- complete palatal coverage
- u shaped palatal connector
22) What are the objections to using the single palatal bar-type
major connector?
- should not be used to connect anterior replacements with
distal extension bases.
23) What maxillary connector is the most rigid and covers the
least soft tissue.
- AP strap
24) In what situation would you use a palatal strap type
connector?
- Bilateral edentulous spaces of short span in a tooth-supported
restoration.
25) Describe the relationship of rugae, junction of hard
palate/soft palate, gingival crevices and palatal tori.
- See Book.
26) Can adequate support be obtained by resting the palatal
major connectors on tooth incline?
- can lead to slippage of denture causing an orthodontic
movement
27) Does not pertain (SEE BOOK)
28) Why should all gingival crossings be abrupt right angles and
bridge with adequate relief?
- To prevent restriction of blood supply and entrapment of food
debris.
29) Describe the continuous bar mandibular major connector and
list indications.
- When a lingual plate of sublingual bar is otherwise indicated
but the axial alignment of the anterior teeth is such that
excessive blockout of interproximal undercuts would be
required.
30) Describe sublingual bar and its uses.
- Where height of mandibular space is less than 6mm.
31) Indication of AP type strap.
- Excellent abutment and residual ridge, long edentulous spaces,
palatal tori.
32) When is full palatal coverage indicated?
- if some or all anterior teeth remain, class II arch with large
posterior space, class I with one to four missing premolars,
absence of tor.
33) Palatal Plate linguoplate connector (SEE BOOK P63)
34) 5 steps of making major connectors on a diagnostic cast.
-outline bearing areas
-outline nonbearing areas
- outline connector areas
-select connector type
- unification
35) What is a minor connector?
- connect major connector to other components of a denture.
36) What are the functions of a minor connector?
-transfer stress to abutment teeth.
- transfer the effect of the retainers, rests and stabilizing
components.
37) Why should minor connectors be rigid?
- must transfer stress and resist deformation.
38) Describe the shape of minor connectors.
-See Book P.58
39) Identify minor connectors
- See Book P.61
40/41/42/43/44 SEE BOOK
45) What factor may be achieved by the use of anatomic replica
patterns for palatal major connectors?
- ?
46) What are ways to increase bond strength between minor
connectors and acrylic resin bases?
- 3 nail head connectors
- angles formed 90 degrees with framework
Chapter 6
1. Define the word rest as a component of an rpd
any component of a partial denture on a tooth surface that
provides vertical support
2. What are the functions of a rest
the primary purpose is to provide vertical support, but in doing
so, it also:
maintains components in their planned positions
maintains established occlusal relationships by preventing
settling of the denture
prevents impingement on soft tissue
directs and distributes occlusal loads to abutment teeth
overall, it serves to support the position of the partial and to
resist movement toward the tissue
3. Rests are defined by the surface of the tooth that is
prepared to receive the rest. Therefore rests are occlusal rests,
incisal rests, and lingual rests.
4. Describe the form of an adequately prepared occlusal rest
seat
The outline form should be a rounded triangular shape with the
apex toward the center of the
occlusal surface
It should be as long as it is wide, the base (at the marginal
ridge) should be at least 2.5mm.
The marginal ridge must be lowered at least 1.5mm.
The floor of the rest seat should be apical to the marginal
ridge and should be spoon shaped.
Angle formed between the occlusal rest and the vertical minor
connector should be less than 90
degrees.
5. Where is the deepest portion of an occlusal rest seat
located
"should be inside lowered marginal ridge at x." The x in the
picture on page 69 is just at the middle of the spoon shaped part.
Exactly where you think it is!
6. Draw a diagram of the approximate dimensions of an occlusal
rest seat on a molar. a premolar
2.5 mm wide at base of triangle (bucco-lingually), 2.5 mm long
(mesio-distally), marginal ridge lowered 1.5 mm, deepest portion at
center of spoon. These dimensions are the same for molars and
premolars.
7. Why should the angle formed by the rest and the vertical
minor connector from which it originates be less than 90
to direct the occlusal forces along the long axis of the tooth,
also prevents slippage of the prosthesis away from the abutment
8. Under what circumstances would one choose to prep a secondary
occlusal rest on the same tooth
when an existing occlusal rest seat is inclined apically toward
the reduced marginal ridge and it can't be modified (center of
spoon lowered) for fear of pulp perforation
9. Describe the form of adjacent, interproximal occlusal rest
seats
the rests are prepared as individual occlusal rest seats , with
the exception that the preps must be extended farther lingually
than is ordinarily done. This answer doesn't quite seem right. I
would take a look at the picture on page 71 because it seems like
it is also extended further bucally.
10. What advantages are gained by using adjacent, interproximal
occlusal rest seats rather than a single interproximal rest
seat
they are used to prevent interproximal wedging by the framework
and they are designed to shunt food away from the contact
points.
11. Describe an internal occlusal rest seat and relate the
circumstances under which it may be use
a partial denture that is totally tooth supported by means of
cast retainers on all abutment teeth may use intracoronal rests for
both occlusal support and horizontal stabilization. The form of the
rest should be parallel to the path of placement, slightly tapered
occlusally and slightly dovetailed to prevent dislodgement
proximally. If you want to read up a little more on these internal
occlusal rests since we didn't talk about them much, check out page
71-or don't waste your time :0)
12. How does one fabricate an internal occlusal rest seat
internal rests are carved in wax or spark eroded in abutment
castings. Ready made plastic rest patterns are available and can be
waxed into a crown or partial veneer patterns, invested, and cast
after having been positioned parallel to the path of placement with
a dental cast surveyor.
13. Rests may be placed on sound enamel, cast restorations, or
silver amalgam restorations. Which of the three is least desirable
for support of the rests. Why?
I'm still waiting for a definite answer from Dr. Olin. The book
didn't come right out and answer this question and this would be an
excellent test question!
14. When preparing occlusal rest seats immediately adjacent to a
proximal surface that has to be recontoured for optimum location of
other components, which is accomplished first-rest seat preparation
or recontouring of the axial surface of the abutment? Defend you
answer.
the preparation of occlusal rest seats always follows proximal
preparation. If done the other way-the marginal ridge almost always
ends up too thin with the center of the rest seat too close to it.
Usually impossible to correct without making the prep too deep.
15. What is the sequence of operations in preparing an occlusal
rest seat in enamel? Name the cuttingand polishing instruments
used.
use large round bur to lower the marginal ridge and to establish
the outline form of the rest seat
then a slightly smaller round bur is used to deepen the rest
seat. The prep is smoothed by a polishing point. Fluoride gel
should be applied to abutment teeth following enamel
recontouring.
16. How do you handle a small enamel defect encountered in
preparing a rest seat.
ignore it until the rest prep has been completed, then with
small burs prepare the remaining defect to receive a small
restoration.
17. Suppose you expose dentin in preparing an occlusal rest seat
in enamel-what then?
Again, awaiting an answer from Dr. Olin
18. Describe the form of a lingual rest seat preparation
slightly rounded V shape (pointed incisally) at the junction of
the gingival and middle third
19. Which unrestored teeth may sometimes have such a lingual
contour that an acceptable lingual rest seat may be prepared in
enamel
mandibular canines
20. Five morphologic or anatomic factors must be evaluated in
determining whether an abutment can support a lingual rest.
Enumerate these five factors.
Sorry!!!! Waiting for Dr. Olin
21. Most often, unrestored canines/ incisors should not be used
for supports for lingual rests. Why?
the lingual slope of the mandibular canine is usually too steep
for an adequate lingual rest seat to be placed in the enamel.
mandibular anteriors have too thin of enamel
22. For what reasons should a rounded, inverted V notch form be
used for a lingual rest seat?
maintains the natural contour of the maxillary canine cingulum,
the v-form is self-centering, and directs forces rather favorably
in an apical direction.
23. State the minimums for a lingual rest seat mesiodistally,
labiolingually, and incisal-apically
MD=2.5 to 3 mm LL=2 mm IA=1.5 mm
24.Give the sequence of use of rotary instruments in preparing a
lingual rest seat in enamel
1. inverted cone diamond
2. progress to smaller tapered stones with round ends
3. shaped abrasive rubber polishing points
4. flour of pumice
25. The design of a framework is such that lingual rest seats
must be placed on incisor teeth, yet dentin will knowingly exposed
in preparing acceptable rest seats. What are the options for
providing adequate rest seats on incisors.
The rest can be built into a cast veneer crown, 3/4 crown,
inlay, laminate veneer, composite restoration, or etched metal
restoration. Individually cast chromium cobalt alloy rest seat
forms that are attached to the lingual surfaces by composite resin
cement can also be used. Sapphire ceramic ortho brackets have also
been bonded to the lingual surfaces of mandibular canines and
shaped as rest seats.
26. The adequacy of a lingual rest seat is better accomplished
with a cast restoration than a preparation confined to enamel. True
or False?
TRUE
27. Four conservative alternatives to forming rest seats on
teeth with unacceptable lingual contours were described in the
text. What are they and what are their advantages and
disadvantages.
see question 25
28. Describe the contour of an incisal rest seat preparation
rounded notch form at incisal angle of a canine or incisal edge
of an incisor with the deepest portion of the prep apical to the
incisal edge. the notch should be beveled both labially and
lingually. Page 77 has some great diagrams of the incisal rest.
Might be worth checking out cuz it seems a bit different than what
we were taught.
29. What are the minimum acceptable dimensions of an incisal
rest seat
2.5 mm wide, 1.5 mm deep
30. Name and describe several indications for the use of incisal
rests
tooth morphology doesn't permit other designs (ie lingual rest),
restore defective or abraded tooth anatomy, provide stabilization,
full incisal rests can restore or provide anterior guidance
31. Which rest is the most unfavorable in relation to a possible
tipping of the tooth. Which is the most favorable to avoid
unfavorable leverage factors
incisal and occlusal of molar or premolar respectively
32. For what reasons must a rest restore the occlusal, lingual,
or insical morphology of the abutment tooth that existed before the
rest seat preparation
I'm starting to feel like an idiot-can't find this one either!!!
Will let you know asap :0)
Chapter 8: Indirect Retainers
1) What elements prevent movement of the base of a
tooth-supported denture toward the basal seats?
-- Occlusal, lingual or incisal rests.
2) Support of a distal extension removable partial denture is
shared by abutment teeth and residual ridges. The quality of
support furnished by the residual ridges is proportionate to at
least three factors. Name them.
--(No clear answer in ch 8) 1. Length of distal extension base.
2. Location of fulcrum line. 3. How far beyond the fulcrum line the
indirect retainer is placed.
Improper use of any of the above factors will increase the
pressure on the residual ridges.
3) Movement of a distal extension base away from basal seats
will occur as a rotational movement or as ______.
--?. Horizontal maybe
4) What is the difference between fulcrum line and axis of
rotation?
--None. The axis of rotation of a denture is about the fulcrum
line.
5) Identify the fulcrum line on class I arch; class II mod.1;
class IV.
-- class I: Line between two most posterior teeth. Ideally the
mesial of 2nd premolars.
-- class II mod. 1: Diagonal line passing through abutment on
distal extension side and most posterior abutment on opposite
side.
-- class IV: Line passes through two abutments adjacent to
single edentulous space.
6) Define Indirect Retainer.
-- The rigid components of the denture framework that are
located on definite rests on the opposite side of the fulcrum line
away from the distal extension base.
7) What components of a removable partial denture usually make
an indirect retainer?
-- One or more rests and supporting minor connectors. Proximal
plates adjacent to edentulous spaces.
8) From the standpoint of leverage advantage, where should an
indirect retainer be located?
-- As far away from the fulcrum line as possible at right angle
to fulcrum line.
9) An indirect retainer performs one major function and four
auxiliary functions. Name them.
-- Major: Activate the direct retainer to prevent movement away
from the tissue.
-- Minor:
1) Reduce anteroposterior tilting leverages on the principle
abutments.
2) Stabilize against horizontal movement by contacting axial
surfaces.
3) Anterior teeth supporting a indirect retainers are stabilized
against lingual movement.
4) Act as auxiliary rest to support portion of major connector.
This helps distribute stress.
5) Provide first visual indication for need to reline and
extension base partial. Dislodgement of indirect retainers
indicates deficiencies in basal seat support.
10) The effectiveness of indirect retainers is influenced by
four factors. Name them.
1) Principle occlusal rests on primary abutments must be
reasonably help in their seats by retentive arms of direct
retainers. If rests are displaced from their seats, no rotation
about the fulcrum line will occur, thus the indirect retainers will
not engage.
2) Distance from the fulcrum line. Must also consider;
a) Length of the distal extension base.
b) Location of the fulcrum line
c) How far beyond the fulcrum line the indirect retainer is
placed.
3) Rigidity of the connectors supporting the indirect
retainer.
4) Effectiveness of the supporting tooth surface. Indirect
retainer must be placed on a definite rest seat where no slippage
or tooth movement will occur. Tooth inclines and weak teeth should
never be used.
11) What are the probable sequelae of trying to use a continuous
bar or linguoplate to serve as an indirect retainer?
-- Cingulum bars and linguoplates are not indirect retainers
because they rest on unprepared lingual surfaces. The terminal
rests at either end of the bar/plate are the indirect retainers. If
used as an indirect retainer, movement of the teeth can occur
(ortho).
12) In a class II, mod. 1 arch, especially if the modification
is a long endentulous space, what component may act as an indirect
retainer?
-- The occlusal rest on a secondary abutment tooth. (primary
abutments would be adjacent to distal extension base and most
distal abutment on tooth supported side. Secondary abutment would
be an anterior abutment on the tooth supported side.)
13) Discuss the inadequacy of rugae to act as support for
indirect retention.
-- Often a part of palatal horseshoe design. Not as good as
tooth support. Rugae support should be avoided when possible.
14) True/False: Each design of the extension base-type RPD
should include an indirect retainer or some component that will act
as an indirect retainer.
-- TRUE
15) True/False: Bilaterally placed indirect retainers contribute
to stability of class I restoration more so than a single indirect
retainer.
-- TRUE (Centrals are too weak for an indirect retainer so
bilateral premolar retainers are preferred. Closer to fulcrum line
[less lever action] but stronger teeth.)
Chapter 9
1. What is a denture base?
A. Supports the artificial teeth and receives functional forces
for occlusion and transfers functional forces to supporting oral
structures.
2. What does the term basal seat mean?
A. The oral tissues and structures of the residual ridge
supporting a denture base.
3. Is the primary purpose of a denture base related to the
masticatory function? If so, how?
A. Yes. Functional stability for distal extensions is most
critical. It must provide the ability to transfer forces without
undue movement.
4. Describe how the denture base contributes to the factor of
appearance.
A. A base must simulate the natural-looking contours and
tinting.
5. Are the functions of tooth-supported and extension-type bases
somewhat different? If so, how do they differ?
A. In a tooth-supported RPD the forces are directed to
abutments. Extension-type transfer stresses to soft tisues.
6. What are the functions of a tooth-supported partial denture
base?
A. A span between two abutments supporting artificial teeth.
7. Describe the functions of a distal extension partial
denture.A. Proved a means to attach denture teeth and dissipate
occlusal forces
8. The space available for a denture base is controlled by the
structures surrounding the space and their movements during
function? True or false?
A. True
9. Explain the snowshoe principle as it applies to denture base
design.
A. Broad coverage furnishes the best support with the least load
per unit area. Providing for maximum support.
10. By what means is an acrylic resin base attached to a
framework?
A. By means of a minor connector designed so that a space exists
between tissue and meshwork. Accomplished by nailhead retention,
retention loops or diagonal spurs placed at random.
11. A ladderlike minor connector is used to attach an acrylic
resin base to frameworks. Should this minor connector be regid or
flexible? Why or why not?
A. Rigid. Provides strength (not 100% sure on this one)
12. Is it important and that a minor connector for an extension
type of acrylic resin base be located on both the buccal and
lingual sides of the residual ridge? Explain.
A. Yes, minimize warpage
13. Is an open ladder type of design for connecting an acrylic
resin base to a major connector preferable to a closed meshwork
design? Why?
14. Give a rule of thumb for how far the minor connector should
extend posteriorly.
A. Extend buccally within physiologic tolerance of border
structures. Mx: cover both Mx tuberosities, extend into the
pterygomaxillary notches and provide for adaption along the
posterior border, taking care not to extend beyond the soft palate
flexure. Mn: bilateral distal extension RPD bases cover the
retromolar pads and extend into the retromylohyoid fossae
15. The minor connector for acrylic resin bases must be totally
embedded in the acrylic resin base. What thickness of acrylic resin
is necessary between the residual ridge and minor connector to
allow adjustment of the base if it should become necessary?
A. We use 2X28 gage
16. Nine requirements for an ideal denture base are given in
this chapter, list six.
1. Accuracy of adaptation to the tissue, with minimal volume
change
2. Dense, nonirritating surface capable of receiving and
maintaining a good finish
3. Thermal conductivity
4. Low specific gravity; light weight in the mouth
5. Sufficient strength; resistance to fracture or distortion
6. Easily kept clean
7. Esthetic acceptability
8. Potential for future relining
9. Low initial cost
17. Metal bases have distinct advantages over acrylic resin
bases, such as thermal conductivity and accuracy and permanence of
form. What are the other advantages?
A. Can be thinner, easier to keep clean, minimize bulk
18. What are the indications and contraindications for metal
bases?
A. Metal is thinner, thermal conductivity, strength
B. Contras: esthetics, functional tongue and cheek contours
19. Can denture base contours for functional cheek and tongue
contact best be accomplished with acrylic resin or metal? Why?
A. Acrylic Resin. You can create bulk with out the added
weight.
20. Relining of extension bases becomes necessary to reestablish
support of the base. Could this be a factor in selecting the
material for a denture base? Explain.
A. Acrylic resin that can be relined to adjust for changing
tissues and demands. Metal cannot.
21. How can it be determined when a denture base requires
relining?
A. When there is loss of occlusal contact (there may be
more?)
22. What is meant by the word stress-breaker in removable
partial pros?
A. A connection that dissipates vertical stresses (Hinge)
23. By what means can the action of the retaining elements of a
stress-breaker be separated from movements of the extension
base?
A. Allows independent movement of denture base and direct
retainers.
24. Stress-breakers may be divided into two broad groups. Give
two examples of each group.
A. The book wasnt really clear on this one. There are hinge type
and split bar type.
Good luck everybody. If anybody has questions on this section
drop me an email: [email protected] or call 218-791-0662CHAPTER
10
1. Nine factors that influence the design of a partial
denture:
a. tooth or tissue support
b. amount of supporting bone
c. crown/root ratio
d. crown/root morphology
e. tooth number and position in arch relative to edentulous
space
f. presence of residual ridge
g. variable tissue support
h. functional forces from opposing arch
i. opposing arch tooth position different occlusion
2. How is the design of a denture influenced by the
classification of the arch being restored?
The type of arch presents various types of coverage forces and
occlusion. RPDs opposing natural teeth will require greater support
and stabilization because greater functional load demands
3. Two main types of dentures and why?
a. Kennedy class I and II-primary support tissue under base,
secondary support from abutment teeth
b. Kennedy class III- all support derived from abutment
teeth
4. Refer to book- Essay question
5. Definition of Guiding Plane:Two plus vertically parallel
surfaces of abutment teeth shaped to direct a prosthesis during
placement and removal. They are parallel to path of insertion and
preferably the long access of abutment teeth.
6. Three main functions of guiding plane surfaces contacted by
minor connectors:.
a. Provide one path of placement and removal
b. Insure intended actions of reciprocal, stabilizing, and
retentive components
c. Eliminate food traps btn. Abutment teeth and denture
7. Should guiding planes on enamel surface of abut teeth be
rounded or flat? Why?
a. Rounded, to avoid B or Li line angles bc line angles weaken
either or both parts of clasp assembly
8. Rule of thumb for prox guide planes?
a. Half width of distance btn tips of adjacent B and Li cusps or
1/3 B to Li width of tooth
9. Direct retainers for tooth supported dentures differ in
design from those used in extension base-type dentures. What
requirement, in relation to undercut, exists for direct retainer
(clasp) on a terminal abut of extension denture when denture base
is forced into heavier contact with residual ridge?
a. Prevent horizontal movement, allow flex of retentive clasp,
clasp arm must be freely flexible in any direction. Round, tapered
clasp form offer advantages of more uniform flexibility, less tooth
contact, and better esthetics.
10. Name component of RPD that must be rigid. Name flexible
parts.
a. Rigid- Minor connectors that join rests and clasp assemblies
to major connector, reciprocal arm clasps
b. Flexible- retentive arm clasp
11. Would a fixed partial denture be a better than RPD?
a. Totally depends on patient preferences and clinical
presentation
12. What method used to replace single missing teeth or missing
ant. Teeth
a. Preferably bridge, implant, maybe nothing
13. when confronted with K class 1, should you replace premolars
with fixed partial?
a. No, nothing distal as an abutment
14. Amount of stress transferred to supporting edent ridge and
abut teeth in extension based partial are dependent on 4
factors.
a. length of lever arm or denture bases
b. an anterior placement of indirect retainer
c. use lingual plate or bar
d. occlusal rest versus cingulum rest
15. Systematic approach to designing RPD. Outline different
approaches. (Too Broad)
16. In evaluating potential support abut teeth can provide (K
class 1), what specific characteristics of teeth should be
considered?
a. Crown/ root ratio
b. Perio health
c. Orientation
17. In eval potential tissue support that edent ridge can
provide in extension base situations, what characteristics should
be considered?
a. Shape and amount of underlying bone
b. Amount of gingival soft tissue
18. Supporting units and functional stresses of K class 1 RPD?
Vague question.
19. In developing a design for an extension base RPD when does
one determine how denture is retained?
a. After analyzing undercuts and patient preference
20. How does oneknow if indirect needs to be incorporated into
the design?
a. Always
21. What is the final step in the proposed systematic approach
to design?
a. They ask about a systematic approach but it is never
explained here, Know different designs and when, where rests /
retention placed, indirect retention, eval ridges, etc.
22. What is a splint bar?
a. Splint used to connect a double abut for stability between
sides of an arch when replacing ant teeth in K class 4.
23. Draw a splint bar. Yeah right. See page159
24. Purpose served by of splint bar.
a. See question 22
25. Enough about splint bars.
26. Why must splint bar be convex rather concave adjacent to
residual ridges?
a. Doesnt actually say but probably to avoid tissue
irration.
27.
Chapter 10 Principles of Removable Partial Denture Design
(this chapter would be excellent to read before the
practical!)1. The text suggests at least nine factors that will
influence the design of a removable partial denture. Please list
them.
Tooth vs tissue supported
Amount of supporting bone
Crown/root ratios
Crown and root morphologies
Tooth number and position in the arch relative to the edentulous
spaces
For a tooth tissue supported prosthesis-the residual ridge for
support
Opposing arch tooth positions
Existing and nature of prosthesis support in the opposing
arch
Potential for establishing a harmonious occlusion (this ones
retarded but it makes 9 :0)
2. How is the design of a denture influenced by the
classification of the arch being restored.
The main difference is in the type of support-whether that be
tissue, tooth, or tooth-tissue.3. There are really only two types
of removable partial dentures. What are they?
Kennedy class I / II vs Kennedy class III. 4. Because there are
two basic types of removable partial dentures, it is evident that a
dentist must consider 1) the manner in which each is supported 2)
the method of impression registration 3) the need of or lack of
need for indirect retention and 4)the use of a base material that
can be readily relined. Write a meaningful essay of 100 words or
less about each of these listed considerations.
The answer to this question is pp 146-148. Kinda helpful.5. What
is a guiding plane?
Defined as two or more parallel, vertical surfaces of abutment
teeth, so shaped to direct a prosthesis during placement and
removal6. What are the three main functions of guiding plane
surfaces contacted by minor connectors?
1) to provide for one path of placement and removal of the
restoration to eliminate detrimental strain to abutment teeth and
framework components during placement and removal 2) to ensure the
intended actions of reciprocal, stabilizing, and retentive
components to provide retention against dislodgement of the
restoration when the dislodging force is directed other than
parallel to the path of removal and also to provide stabilization
against horizontal rotation of the denture 3) to eliminate gross
food traps between abutment teeth and components of the denture7.
Should guiding planes prepared on enamel surfaces of abutment teeth
be rounded or flat, why?
The guide planes should be rounded. The reason for this is to
avoid creating buccal or lingual line angles that could be produced
in flat guide planes. These line angles would weaken the clasp
assembly that contacts it.8. Give a rule of thumb for the
dimensions of proximal guiding planes
Guide planes should be one half the width of the distance
between the tips of adjacent buccal and lingual cusps or about one
third of the buccal lingual width of the tooth.
9. Direct retainers for tooth supported dentures differ in
design from those used in extension base type dentures. What
requirement, in relation to an undercut, exists for the direct
retainer on a terminal abutment of an extension denture when the
denture base is forced in to heavier contact with the residual
ridge
Must be able to flex sufficiently to dissipate stresses that
otherwise would be transmitted directly to the abutment tooth as
leverage. Some dentists prefer stress-breakers, others believe
wrought wire are the best for this.
10. Name the components of a removable partial denture that must
be rigid. Name the components in which flexibility is desirable
The rigid ones are major connectors, minor connectors and
reciprocal clasp arms (the stabilizing components). The flexible
ones are direct retainers (retentive clasps) in tooth supported and
for distal extensions partial dentures.11. Would you agree that a
fixed partial, where indicated, should be the restoration of
choice, in lieu of a removable partial? Give an example and
explain.
Sorry, my clinical judgment at this point is a little lacking.
The book doesnt answer this question and I guess Ill email this to
Dr Olin. My guess is this question is just trying to make the point
that each situation is going to be different depending on the
health of the remaining teeth, the patient (ie dexterity, finances,
etc), the disease process in the patient (ie rampant caries),
etc.
12. What method should usually be used to replace single missing
teeth or missing anterior teeth? Justify your answer.
A fixed partial denture (from chapter 14)
13. When confronted with a Kennedy class I arch in which all
molars and first premolars are missing, should one consider
replacing the first premolars with fixed partials rather than
restoring the spaces with a removable restoration? Why?The answer,
of course, would be dependent on the clinical situation. However,
if the 2nd premolars turned out to be weak abutments on their own,
the splinting of the canine and 2nd premolar by a fixed partial
denture can provide adequate support for abutment. The answer is
yes-the first premolar should be restored by a fixed partial.14.
The amount of stress transferred to the supporting edentulous
ridges and the abutment teeth in extension base partial dentures is
dependent on four factors. One is the length of the lever arm or
denture bases. Identify the other three and describe how each
influences this stress transfer.
1) direction and magnitude of the force 2) the quality of
resistance (support from the remaining natural teeth and edentulous
ridge) 3) the design characteristics of the partial denture.
15. A systematic approach to developing the design for any
removable partial denture was presented and discussed. Outline the
steps presented in this approach.
1) determine how the partial denture is to be supported (ie
rests and tissue stops)
2) connect the tooth and tissue support units (ie major and
minor connectors)
3) determine how the rpd is to be retained (ie clasps)
4) connect the retention units to the supporting units
5) outline and join the edentulous area to the already
established design components16. In evaluating the potential
support that abutment teeth can provide, what specific
characteristics of the teeth should you consider?
1) periodontal health 2) crown and root morphologies 3) crown to
root ratio 4) bone index area 5) location of the tooth in the arch
6) relationship of the tooth to other support units aka length of
the edentulous span 7) the opposing dentition17. In evaluating the
potential tissue support that the edentulous ridges can provide in
extension base situations, what specific characteristics should be
considered
1) the quality of the residual ridge 2) the extent to which the
residual ridge will be covered by the denture base 3) the type and
accuracy of the impression registration 4) the accuracy of the
denture base 5) the design characteristics of the component parts
of the partial denture framework 6) the anticipated occlusal
load18. In developing the design for an extension base rpd, what
component parts are used to connect the supporting units? What
specific characteristics should each of these components have to
effectively distribute functional stresses to the supporting
units?
Major connectors should be properly located in relation to
gingival and moving tissues and should be designed to be rigid.
Rigidity in a major connector is necessary to provide proper
distribution of forces to and from the supporting components. Minor
connectors should be located in interproximal spaces to provide
adequate bulk of material without impinging on the tongue.19. In
developing a design for an extension base rpd, when does one
determine how the denture is to be retained? What are the keys to
selecting successful clasp designs
Retainers for distal extension rpds have to be able to flex or
disengage when the denture base moves toward the tissue when in
function. Thus, the retainer may act as a stress breaker. Clasps
that act as stress breakers, rather than a mechanical stress
breaker, provide the same stress relief without compromising the
horizontal stabilization of the rpd. The clasp must be freely
flexible in all planes-rounded tapered clasps are the best.
Therefore, the wrought wire circumferential or a carefully designed
bar clasp can be used. 20. How does one know if indirect retention
needs to be incorporated into the design? If needed, where should
it be located, and what component parts would be included in the
design to serves as indirect retainers?
Indirect retention is placed in situations where a fulcrum line
exists. Fulcrum lines exist only where a distal extension is
present (ie no fulcrum line exists in a kennedy class III-Dr. James
said this is a classis test question). Indirect retention should be
placed as far anterior (and at a right angle) to the fulcrum line,
on a tooth that is capable of withstanding the forces placed on it.
Therefore a canine or premolar should be used. An incisal or
cingulum rest seat should be used. This describes the first purpose
of indirect retention-to prevent rotation of the rpd about the
fulcrum line. The second purpose of indirect retention is in
support of the major connector- for example, a long lingual bar can
be prevented from settling into the tissue if indirect retention is
incorporated. Remember-a lingual plate is not an indirect retainer,
it is located on inclined tooth surfaces which make it an ortho
appliance. 21. What is the final step in the proposed systematic
approach to design? Should this design characteristic have any
special requirements? If so, what are they?
The final step was to outline and join the edentulous area to
the already established design components (see question 15). The
amount of flexure of the distal extension will affect the retentive
clasp requirements. For example, if the edentulous ridge is greatly
resorbed, the span is especially long, or excessive occlusal load
is placed on the extension, greater flexure of the clasp will be
required. These examples will also be important in considering how
the minor connector will contact the abutment tooth adjacent to the
extension in order to prevent torque on that abutment tooth. There
is a good diagram on page 149 explaining this phenomenon that is
difficult to explain in words. 22. What is a splint bar?
As answered in a previous question-missing anterior teeth are
best replaced with a fixed partial. However, some situations exist
in which several missing anterior teeth need to be replaced with
the rpd (ie replacing a long span of anterior teeth). When this is
the case-the splint bar acts as the major connector to connect the
abutment teeth in a long span in order to provide support to the
replaced anterior teeth. There is a good picture on page 159 to get
an idea of what it looks like. 23. Draw a splint bar from a
frontal, horizontal, and sagittal view. Label the dimensions and
relationship of the bar to the tissue and the abutments.
The splint bar should be round or ovoid. As viewed from above,
the splint bar should be in a straight line between the abutments.
In a sagittal section, a rounded pear shape makes point contact
with the ridge (prevents rotational torque). The bar should be
placed slightly lingual to the ridge to provide esthetic
arrangement of the artificial teeth.24. What purposes are served by
use of splint bars where indicated?
Enhances longevity of the teeth being replaced and stability of
the rpd. Basically, just think of it as a sturdy structure for a
long span of artificial teeth to rest on. If flexure of the long
span occurs, this prevents the fracture of the span. Kinda like a
sturdier grid work that is between two abutments.25. A decision has
been made to use a splint bar from canine to canine. Will this
decision influence the design of the framework? If so, how?
The major design difference in using a splint bar is that the
bar actually serves as the major connector, so the traditional
major connector is not needed.26. For what reasons must a splint
bar be convex, rather than concave, adjacent to the residual
ridge?
The splint bar needs to be concave in order for the patient to
be able to keep it clean (flossing). Think of the hygienic pontic
we learned about-same principles.27. Is a 13 guage splint bar
adequate for a span from canine to canine? Why or why not?
NO-long spans require more rigid bars (10 guage)28. Describe and
define an internal clip attachment
The internal clip attachment differs from the splint bar in that
the internal clip provides both support and retention from the
connecting bar. See figure 10-17 on page 161 for picture.
Basically, a connecting bar is placed (for example) between two
canines and is raised slightly off of the edentulous ridge. Then, a
nylon or metal clip is secured in the tissue contacting side of the
rpd. The clip is contoured to fit the bar and kinda snaps around
the bar. The use of the bar and clip provides support, stability,
and retention for the anterior modification area and it may allow
one to eliminate both occlusal rests and retentive clasps on the
adjacent abutment teeth.29. The internal clip attachment must be
used in conjunction with some type of bar supported by abutment
teeth. What is the cross-sectional shape of such a bar? What
advantages accrue from using such a design for a restoration?
The previous question answered this one except that the bar
should be round and straight in order for the clip to be able to
engage it.30. You are confronted with a mandibular arch with only
the six anterior teeth and two second molars remaining. The
maxillary arch is edentulous. The anterior teeth are restorable
individually and show no mobility or periodontal involvement. The
molars, however, are grossly involved with caries, in fact most of
the clinical crown is gone. They also show a Miller mobility
classification of 1 and exhibit a 5 to 6 mm gingival crevicular
depth. They can be treated periodontally and endodontically. In
such a situation, if finances were not a factor, would you 1)
extract both molars 2) prepare the molars for an overlay prosthesis
3) extract all the mandibular teeth and treat the patient with
complete dentures?
Every consideration should be directed at preventing the need
for a distal extension. In this situation, one would prepare the
molars for an overlay prosthesis. If teeth can be endo treated,
perio treated, and have not tipped (ie from opposing occlusion),
they can serve as abutments. The tooth is prepared in a way that it
ends up as a slightly elevated (just slightly above the tissue)
dome shaped abutment for which the rpd will engage. This eliminates
the need for a distal extension.31. If the molars mentioned in the
preceding section were prepared for an overlay prosthesis, state
the reasons for doing so in terms of benefits to the patient.
This eliminates the need for the distal extension and problems
that go along with the distal extension (ie more torque on the
abutment teeth, pressure placed on the residual ridge, etc.)Chapter
11: Surveying
1) Define a dental cast surveyor.
An instrument used to determine the relative parallelism of 2+
surfaces of teeth or other parts of the cast of a dental arch.
2) What are the basic parts of a surveyor?
-Platform on which the base is moved
-Vertical arm that supports superstructure
-Horizontal arm from which surveying tools suspend
-Table to which the cast is attached
-Base on which the table swivels
-Paralleling tool or guidance marker (contacts the convex
surface of the tooth)
-Mandrel for holing special tools
3) What does the height of contour mean? How does is relate to a
direct retainer assembly?
Height of contour line encircling a tooth, designating its
greatest circumference at a selected position determined by a
surveyor.The height of contour determines the location of
non-retentive reciprocal and stabilizing arms and the location of
retentive clasp terminals.
4) Because no component of a removable partial denture may
engage an undercut except a portion of the retentive arm of a
direct retainer, then both desirable and undesirable undercuts must
be known in deigning a restoration. True or False?
True
5) When planning the design of a partial denture, 4 factors must
be considered in determining the path of placement and removal. Two
of these factors are retention and esthetics. Name the 2 other
factors.
Guiding planes and Interference6) With the diagnostic cast
securely clamped to the adjustable table and the diagnostic stylus
in the vertical spindle, what orientation of the occlusal plane to
the base of the surveyor is recommended as a provisional study
position?
The occlusal surfaces are approximately parallel to the
platform.
7) When considering a design for a class III, modification 1
arch, which directional tilt of the cast will indicate the greatest
area of parallel proximal surfaces to act as guiding planes
anteroposterior or lateral?
Anteroposterior
8) Suppose in the previous situation, that the diagnostic stylus
touches only gingival areas of the proximal surfaces. What are the
options to obtain guiding plane surfaces?
In making the choice btw. having contact with a proximal surface
at the cervical area only or at the marginal ridge only, contact at
the marginal ridge is preferred b/c a plane can be established by
recontouring. When only a gingival contact exists a restoration in
the only means of establishing a guiding plane.
9) When possible retentive areas are being ascertained, the cast
is tilted laterally. How can one avoid changing the established
anteroposterior tilt of the cast?
Rotate it about an imaginary longitudinal axis with out
disturbing the anteroposterior tilt already established.
10) Uniformity of retention bilaterally is desirable. In what
manner does the angle of cervical convergence contribute to
obtaining uniform retention?
The amount of retention existing below the height of convexity
may be determines by observing the angle of cervical convergence
and tilting the cast laterally until similar areas of retention
exist on the principal abutment teeth.
11) What are the most common causes of interference to the
placement of a mandibular major connector?
Bony prominences and lingually inclined premolars are the most
common causes of interference to a lingual bar connector.
12) Why should soft tissue contours be surveyed along with
teeth?
Bony undercuts may interfere with seating of the denture base.
An undercut may also leave too large of a gap for the minor
connector of an I-bar which would leave objectionable spaces and
trapping of food.
13) What advantages accrue in having the tip of the carbon
marker touch the gingival areas intermittently when marking the
heights of contour of abutment teeth?To ensure that you are not
recording a false height of contour and that the carbon marker is
reaching the height of contour. (this was not in the book, I asked
Dr. Madden if he knew the answer Dr. Olin was gone that day and he
did not know the answer either, so this is just my best guess. Im
sending an email to Dr. Olin to ask, when he responds I will let
you all know.)
14) After the diagnostic cast has been surveyed, how can the
relationship of the cast to the vertical spindle of the surveyor in
three dimensions be recorded?
There are two methods:
Tripoding: Place three widely divergent dots on the tissue
surface of the cast using the tip of a carbon marker, with the
vertical arm of the surveyor in a locked position. Preferably these
dots should not be placed on areas of the cast involved in the
framework design. The dots should be circled with a colored pencil
for easy identification.
Score two sides and the dorsal aspect of the base of the cast
with a sharp instrument held against the surveyor base. By tilting
the cast until all three lines are again parallel to the surveyor
blade, the original cast position can be reestablished. Scratch
lines will be reproduced in any duplication, thereby permitting any
duplicate cast to be related to the surveyor in the a similar
manner.
15) What is the disadvantage of using a carbon marker that is
even slightly worn?
A worn (tapered) carbon marker will indicate heights of contour
more occlusally located than they actually exist.
16) What is an undercut gauge? How can it be used to measure the
depth of undercut in the angle of cervical convergence?
An undercut gauge is an attachment to the surveyor which
measures the amount of undercut in hundredths of an inch. To use
the undercut gauge, place the vertical portion of the gauge against
the height of contour on the axial surface of the tooth and the
edge of the horizontal portion against the axial portion of the
tooth below the height of contour so that both are touching at the
same time. This will allow you to determine where you have