Diag in rpd/endodontic courses

Seminar on
DIAGNOSTIC SETUP
FOR
REMOVABLE PARTIAL DENTURE
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

Introduction.
History
Oral examination
Visual examination.
Radiographic examination
Oral prophylaxis.
Exploration.
Vitality tests.
Diagnostic cast.
Cast analysis.
On articulator.
On surveyor.
Interpretation of data.
Summary.

Introduction
• When an RPD ceases to function as intended by the
dentist or as expected by the patient. It is generally
considered to be in a stage of failure. Most failures
result from a deficiency in design or from alterations of
the supporting tissues during or after fabrication of the
prosthesis. The causes of failure can be categorized
under inadequate diagnosis and treatment planning,
inadequate mouth preparation.

Unfortunately, too many RPDs are designed
without the use of a dental surveyor. Without
question, the dental surveyor is an essential
instrument that aids the dentist in making an
accurate diagnosis. Surveying identifies those
areas of the mouth that need to be modified to
accommodate the design of a prosthesis that will
promote and maintain oral health.
Inadequate Diagnosis :

Inadequate mouth preparation
• A second kind of failure results when the dentist
does not provide for adequate tooth support by
the proper positioning and contouring of the
clasp (direct retainer) or for proper tissue
support by tissue-conditioning methods and
corrected impressions. Also included in this
category is the failure of the dentist to create
occlusal harmony of the remaining natural
dentition before mouth preparation for the RPD.

History
• Patient interview, during which the dentist
should establish rapport with the patient,
gain insight in the psychological make-up
of the patient, explore any physical
problems that may affect the treatment
and ascertain the patient’s expectations of
treatment.

Establishing a rapport.
• De Van 1961 stated it when he said we
should meet the mind of the patient before
we meet the mouth of the patient.
• The patients attitude and opinion relative
to dentistry can greatly influence the
success or the failure of the treatment.

Psychological make-up:
• In 1950 Dr. M M House classified patients
into
Philosophical
Histerical
Exacting
Indifferent
• The patients attitude and psychological
make up have considerable influence on
the success of the treatment.

Physical problems on Rx:
• Any positive response in the health
questionnaire must be explored and
evaluated.
• Systemic disturbances that can have a
significant effect on treatment of the
patient include the following…..

Diabetes:
• Uncontrolled diabetes is frequently
accompanied by multiple small oral
abscesses and poor tissue tone and often
has a reduced salivary output.

Arthritis:
• If arthritic changes occur in the TMJ, the
making of jaw relation records can be
difficult and changes in the occlusion may
occur.

Paget’s disease:
• May have enlargement of the maxillary
tuberosities, which can cause changes in
the fit and the occlusion of the prosthesis.

Acromegaly:
• Patients with acromegaly may have
enlargement of the mandible.
• They should be observed frequently to
evaluate the fit and occlusion of the
prosthesis.

Parkinson’s disease:
• Characterized by the rhythmic
contractions of the musculature, including
muscles of mastication.
• The symptoms are some times so severe
that it is impossible for the patient to insert
and remove the RPD.

Pemphigus vulgaris:
• Is a disease that usually begins by the
formation of bullae in the oral cavity with
gradually spreading to the skin.
• In the acute phase a painful oral cavity
and dryness of the mouth are common
symptoms.

Epilepsy:
• A grand mall seizure may result in fracture
and aspiration of the prosthesis and
possibly the loss of additional teeth.
• The construstion of RPD is usually
contraindicated if the patient has frequent
severe seizure with little or no warning.

C V S disease:
• Patients with the following require medical
consultation before any dental
procedure……
• Acute or recent MI
• Unstable or recent onset of Angina
pectoris, Congestive Heart Failure,
Uncontrolled Arrhythmia, uncontrolled
hypertension.

Transmissible diseases:
• Hepatitis
• Tuberculosis
• Influenza
• And other transmissible disease pose a
particular hazard for the dentist, patient,
dental auxiliaries.

Effect of drugs on treatment
• Increase in age usually means an
increase in…………………………
• The need for some type of prosthodontic
treatment.
• The use of prescribed and over the
countered dugs

Diagnosis – The determination of the nature of the
disease.
ORAL EXAMINATION
A complete oral examination should precede any mouth
rehabilitation procedures.
An oral examination should be complete, not limited to only one
arch.
It should include a visual and digital examination of the teeth and
surrounding tissues with mouth mirror, explorer, periodontal
probe, a complete intraoral radiographic survey, vitality tests of
critical teeth and an examination of casts correctly oriented on an
adjustable articulator and on a surveyor.

Sequence of oral examination: An oral examination should be
accomplished in the following sequence.
1. VISUAL EXAMINATION
Visual examination will reveal many of the signs of dental disease.
Consideration of caries susceptibility is of primary importance.
The number of restored teeth present, signs of recurrent caries, and
evidence of decalcification should be noted.
At the time of the initial examination, periodontal disease, gingival
inflammation, the degree of gingival recession, and mucogingival
relationships should be observed.

A complete periodontal charting that includes pocket depths,
assessment of attachment levels, furcations, mucogingival
problems, and tooth mobility should be performed.
The extent of periodontal destruction must be determined with
both appropriate radiographs and by use of the periodontal probe.
The number of teeth remaining, the location of the edentulous
areas, and the quality of the residual ridge will have a definite
bearing on the proportionate amount of support that the partial
denture will receive from the teeth and the edentulous ridges.
Tissue contours may appear to present a well-formed edentulous
residual ridge.

Palpation often indicates that supporting bone has been resorbed
and has been replaced by displaceable, fibrous connective tissue.
Such a situation is common in maxillary tuberosity regions. The
removable partial denture cannot be supported adequately by
tissues that are easily displaced.
The presence of tori or other bony exostoses must be detected and
an evaluation of their presence in relation to framework design
must be made.
During the examination, not only must each arch be considered
separately, but also its occlusal relationship with the opposing
such.
A situation that looks simple when the teeth are apart may be
complicated when the teeth are in occlusion.www.indiandentalacademy.com

Complete intraoral radiographic survey
The objective of a radiographic examination are
(1) to locate areas of infection and other pathosis that may be
present;
(2) to reveal the presence of root fragments, foreign objects,
bone spicules, and irregular ridge formations;
(3) to reveal the presence and extent of caries and the relation
of carious lesions to the pulp;
(4) to permit evaluation of existing restorations as to evidence
of recurrent caries, marginal leakage, and overhanging
gingival margins;

(5) to reveal the presence of root-canal fillings and to permit
their evaluation as to future prognosis
(6) to permit an evaluation of periodontal conditions present
and to establish the need and possibilities for treatment; and
(7) to evaluate the alveolar support of abutment teeth, their
number, the supporting length and morphology of their
roots, the relative amount of alveolar bone loss suffered
through pathogenic processes, and the amount of alveolar
support remaining.

A thorough and complete oral prophylaxis
An adequate examination can be accomplished best with the teeth
free of accumulated calculus and debris.
Also, accurate diagnostic casts of the dental arches can be obtained
only if the teeth are clean;
The exploration of teeth and investing structures
These can be explored by instrumentation and visual means. This
should include a determination of tooth mobility and an
examination of occlusal relationships.
At this time the presence of tori and other bony protuberances
should be noted and their clinical significance evaluated.

Vitality tests of remaining teeth
Vitality tests should be given particularly to teeth to be used as
abutments and those having deep restorations or deep carious
lesions.
Determination of height of the floor of the mouth to locate
inferior borders of lingual mandibular major connectors.
Mouth preparation procedures are influenced by a choice of major
connectors.

DIAGNOSITC CASTS
A diagnostic cast should be an accurate reproduction of the teeth
and adjacent tissues.
In a partially edentulous arch this must include the edentulous
spaces, since these also must be evaluated in determining the type
of denture base to be used and the extent of available denture
supporting area.
Purpose of diagnostic casts
Diagnostic casts serve several purposes as an aid to diagnosis and
treatment planning.

1) Diagnostic casts are used to supplement the oral examination
by permitting a view of the occlusion from the lingual, as well as
from the buccal, aspect.
Analysis of the existing occlusion is made possible when
opposing casts are occluded, as well as a study of the possibilities
for improvement either by occlusal adjustment, occlusal
reconstruction, or both.
The degree of over closure the amount of interocclusal space
available, and the possibilities of interference to the location of
rests may be determined.
2) Diagnostic casts are used to permit a topographic survey of
the dental arch that is to be restored by means of removal partial
denture.

The cast of the arch in question may be surveyed individually
with a cast surveyor to determine the parallelism or lack of
parallelism of tooth surfaces involved and to establish their
influence on the design of the partial denture.
The principal consideration in studying the parallelism of tooth
and tissue surfaces of each dental arch is to determine the need
for mouth preparation:
(a) proximal tooth surfaces, which can be made parallel to
serve as guiding planes,
(b) retentive and non-retentive areas of the abutment teeth,
(c) areas of interference to placement and removal.
From such a survey a path of placement may be selected that
will satisfy requirements for parallelism and retention to the best
mechanical, functional, and esthetic advantage.www.indiandentalacademy.com

3. Diagnostic casts are used to permit a logical and comprehensive
presentation to the patient of present and future restorative needs,
as well as of the hazards of future neglect. Occluded and
individual diagnostic casts can be used to point out to the patient
(a) evidence of tooth migration and the existing results of such
migration.
(b) Effects of further tooth migration
(c) Loss of occlusal support and its consequences
(d) Hazards of traumatic occlusal contacts and
(e) Cariogenic and periodontal implications of further neglect.

4. Individual impression trays may be fabricated on the
diagnostic cats, or the diagnostic cast may be used in selecting
and fitting a stock impression tray for the final impression.
5. Diagnostic casts may be used a constant reference as the
work progresses.
Penciled marks indicating the type of restorations, the areas of
tooth surfaces to be modified, the location of rests, the design of
the partial denture framework, as well as the path of placement
and removal, all may be recorded on the diagnostic cast for
future reference.

CAST ANALYSIS - ON THE ARTICULATOR
A study of the casts on the articulator reveals relationships
between opposing teeth and between edentulous ridges that could
not be determined by any other methods.
OCCLUSION
The relationship of the teeth of one arch with those of the other
arch can be closely observed.
The presence of tipped, rotated, and extruded teeth can be noted,
and the problems in design of the prosthesis that they create can be
assessed.

OCCLUSAL PLANE
The status of the occlusal plane is critical in assessing the
prognosis for a prosthesis, and it may exert a pivotal influence on
the type of prosthesis that should be prescribed.
A plane that undulates because of tipped and extruded teeth will
make it very difficult to develop a harmonious occlusion.
Because a harmonious occlusion is crucial to the success of a
removable partial denture, the occlusal plane that deviates
markedly form normal must be viewed with consideration.

INTERRIDGE SPACE
The amount of space between the edentulus ridges of the maxilla
and the mandible should be evaluated carefully.
Special attention should be directed to the tuberosity region where
bony and fibrous hypertrophy frequently result in contact between
the residual ridge and the mandibular teeth, or perhaps between the
two endentulous ridges.
Interridge space in the incisor region may be nonexistent as a
result of extrusion of the mandibular incisors into contact with the
palatal mucosa when the teeth are in occlusion

INTEROCCLUSAL SPACE
The space between the occlusal and incisal surfaces of certain key
teeth is crucially important.
Areas of the abutment teeth that are destined to accommodate
occlusal, lingual, or incisal rests should be examined critically in
order to assess the amount of space that is available and to
estimate the additional space that must be provided.
When a lingual rest is required on a maxillary anterior tooth, the
articulated study casts make it possible to view the lingual surface
of the tooth involved with all the teeth in centric occlusion so that
the precise amount of space available for the contemplated rest can
be determined accurately.

CAST ANALYSIS – ON THE SURVEYOR
The path of insertion as well as the design of the prosthesis will be
established with the cast on the surveyor, so that all subsequent
treatment can be based on this design.
SURVEYING THE DIAGNOSTIC CAST
Surveying the diagnostic case is essential to effective diagnosis and
treatment planning. The objectives are as follows:
1. To determine the most desirable path of placement that will
eliminate or minimize interference to placement and removal.
2. To identify proximal tooth surfaces that are or need to be made
parallel so that they act as guiding places during placement and
removal.

3. To locate and measure areas of the teeth that maybe used for
retention.
4. To determine whether tooth and bony areas of interference will
need to be eliminated surgically or by selecting a different path of
placement.
5. To determine the most suitable path of placement that will
permit locating retainers and artificial teeth to the esthetic
advantages.
6. To permit an accurate charting of the mouth preparations to be
made. This includes the preparation of proximal tooth surfaces to
provide guiding planes and the reduction of excessive tooth
contours to eliminate interference and to permit a more acceptable
location of reciprocal and retentive clasp arms.

7. To delineate the height of contour on abutment teeth and to
locate areas of undesirable tooth undercut that are to be avoided,
eliminated, or blocked out.
8. To record the cast position in relation to the selected path of
placement for future reference.
INTERPRETATION OF EXAMINATION DATA
As a result of the oral examination and diagnosis, certain data
should be recorded, much of which are based on decisions that are
the result of the diagnosis and reflect the patient’s present and
predictable health status.
The quality of the alveolar support of an abutment tooth is of
primary importance because the tooth will have to withstand
greater stress loads when supporting a dental prosthesis.www.indiandentalacademy.com

Abutment teeth providing total abutment support to the prosthesis,
be it either fixed or removable, will have to withstand a greater
load and especially greater horizontal forces.
Abutment teeth adjacent to distal extension bases are subjected not
only to vertical and horizontal forces but to torque as well because
of the movement of the tissue-supported base.
Each abutment tooth must be evaluated carefully as to the alveolar
bone support present and the past reaction of that bone to occlusal
stress.

Index areas
Index areas are those areas of alveolar support that disclose the
reaction of bone to additional stress. Favourable reaction to such
stress may be taken as an indication of future reaction to an added
stress load.
The patient is said to have a positive bone factor, which means
the ability to build additional support wherever needed.
Other index areas are those around teeth that have been subjected
to abnormal occlusal loading; that have been subjected to diagonal
occlusal loading caused by tooth migration; and that have reacted
to additional loading, such as around existing fixed partial denture
abutments.
The patient is said to have a negative bone factor, which means
the inability to respond favorably to stress.

Alveolar lamina dura
The alveolar lamina dura is also considered in a radiographic
interpreation of abutment teeth.
The lamina dura is the thin layer of hard cortical bone that normally
lines the sockets of all cortical bone, its function is to withstand
mechanical strain.
In a radiograph the lamina dura is shown as a radiopaque white line
around the radiolucent dark line that represents the periodontal
membrane.

Root morphology
The morphologic characteristics of the roots determine to a great
extent the ability of prospective abutment teeth to resist
successfully additional rotational forces that may be placed on
them.
Teeth with multiple and divergent roots will resist stresses better
than teeth with fused and conical roots, since the resultant forces
distributed through a greater number of periodontal fibers to a
larger amount of supporting bone.

Third molars
Unerupted third molars should be considered as prospective future
abutments to eliminate the need for a distal extension removable
partial denture.
The increased stability of a tooth-supported denture is most
desirable to enhance the health of the oral environment.
Periodontal considerations
An assessment of the periodontium in general and abutment teeth in
particular must be made before prosthetic reconstruction.
One must evaluate the condition of the gingiva, looking for
adequate zones of attached gingival and the presence absence of
pockets. www.indiandentalacademy.com

The condition of the supporting bone must be evaluated and
mobility patterns recorded.
If mucogingival involvements, osseous defects, or mobility patterns
are recorded, the causes and potential treatment must be
determined.
Oral hygiene habits of the patient must be determined, and efforts
made to educate the patient relative to plaque control.
Additionally, the patient must be advised of the importance of
regular maintenance appointments after reconstruction.
The remaining teeth will require meticulous plaque control afterwww.indiandentalacademy.com

Caries activity
Caries activity in the mouth, past and present, and the need for
protective restorations must be considered.
The decision to use full coverage is based on the age of the patient,
evidence of caries activity, and the patient’s oral hygiene habits.
Occasionally three-quarter crowns may as used where buccal or
lingual surfaces are completely sound, but intracoronal restorations
(inlays) seldom indicated in any mouth with evidence of past
extensive caries or pre-carious areas of decalcification, erosion, or
exposed cementum.

Prospective Surgical Preparation
Need for Surgery or extractions must be evaluated.
The same criteria apply to surgical intervention in the partially
edentulous arch as in the completely edentulous arch.
Grossly displaceable soft tissues covering basal seat areas and
hyperplastic tissue should be removed to provide a firm denture
foundation.
Mandibular tori should be removed if they will interfere with the
optimum location of a lingual bar connector or a favorable path of
placement.
Any other areas of bone prominence that will interfere with the
path of placement should also be removed.www.indiandentalacademy.com

The path of placement will be dictated primarily by the guiding
plane of the abutment teeth.
Therefore some areas may present interference to the path of
placement of the partial denture by reason of the fact that other
unalterable factors such as retention and esthetics must take
precedence in selecting that path.
Extraction of teeth may be indicated for one of the following three
reasons.
1. If the tooth cannot be restored to a state of health, extraction
may be unavoidable.
2. A tooth may be removed if its absence will permit a more
serviceable and less complicated partial denture design.

Teeth in extreme mal position (lingually inclined mandibular teeth,
and mesially inclined teeth posterior to an edentulous space) may be
removed if an adjacent tooth is in good alignment and if good support
is available for use as an abutment.
3. A tooth may be extracted if it is so unesthetically located as to
justify its removal to improve appearance.
Need for reshaping remaining teeth
Many failures of partial dentures can be attributed to the fact that the
teeth were not reshaped property to establish guiding planes or to
receive clasp arms and occlusal rests before the impression for the
master cast was made.
Of particular importance are the paralleling of proximal tooth
surfaces to act as guiding planes, the preparation of adequate rest
areas, and the reduction of unfavorable tooth contours.

To neglect planning such mouth preparations in advance is
inexcusable.
The design of clasps is dependent on the location of the retentive,
stabilizing, reciprocal, and supporting areas in relation to a definite
path of placement and removal.
Failure to reshape unfavorably inclined tooth surfaces and, if
necessary, to place restorations with suitable contours not only
complicates the design and location of clasp retainers but also
frequently leads to failure of the partial denture because of poor clasp
design.
A malaligned tooth or one that is inclined unfavorably may make it
necessary to place certain parts of the clasp so that they interfere with
the opposing teeth.

Unparallel proximal tooth surfaces not only will fail to provide
needed guiding planes during placement and removal but also will
result in excessive blockout.
This inevitably results in the connectors places so far out of contact
with tooth surfaces that food traps are created.
To pass lingually inclined lower teeth, clearance for a lingual bar
major connector may have to be so great that a food trap will result
when the restoration is fully seated, and the lingual bar will be
located so that it will interfere with tongue comfort and function.

Reduction of unfavorable tooth contours
Reduction of unfavorable tooth contours will greatly facilitate the
design of the partial denture framework.
The need for modification of tooth contours must be established
during the diagnosis and treatment planning phase of partial
denture service.

DIAGNOSTIC WAX-UP
A diagnostic wax-up is a valuable diagnostic tool, especially if
multiple crowns or fixed partial dentures need to be constructed in
conjunction with a removable partial denture.
Problems involving the position and relationship of the remaining
teeth become apparent.
The diagnostic wax-up provides a guide for tooth preparation and
helps indicate problems that may be encountered in positioning
cusps and in establishing acceptable occlusal contacts.

SUMMARY
An RPD is the restoration of choice under the following
conditions.
1. When there are no posterior terminal abutment teeth present,
so that a distal – extension base is required to support the
prosthesis.
2. When the edentulous spaces are too extensive or too curved
to be successfully restored with tan FPD (Zarb & MacKay, 1981).
3. When there is a need to provide replacement for missing
hard and soft tissues with an acrylic resin denture base in order to
restore normal tissue contours and lip support.

4. When the cross-arch splinting provided by an RPD will be
helpful in supporting and preserving periodontially weakened
teeth.
5. When it is anticipated that additional teeth will be lost
sometime after the fabrication of the prosthesis.
Additional denture teeth may be added to an RPD that has been
designed with this contingency in mind.
A tooth- supported RPD may even be converted to a distal –
extension RPD by the addition of a denture tooth and an
appropriate denture base.

BIBLIOGRAPHY
1. McCracken’s – Removable Partial Prosthodontics
2. Renner & Boucher – Removable Partial Dentures
3. Stewart – Clinical Removable Partial Prosthodontics
4. A Roy MacGregor – Removable Partial Prosthodontics
5. Grasso & Miller – Removable Partial Prosthodontics
6. GPT–7

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