PDI Flashcards
Dentistry uses many classification systems
* Despite challenges (not always applicable, agreement not always present…)
* Examples
(3)
- ASA
- Kennedy’s classification of edentulous space and Applegate’s rules
- Other disciplines have classification systems
Main Advantage:
* Comprehensive evaluation and Assessment of all necessary parameters to help in
(3)
Diagnosis, Treatment, and Prognosis
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Prosthodontic Diagnostic Index (PDI)
Potential benefits of the system include:
(7)
(1) improved intraoperator consistency
(2) improved professional communication
(3) insurance reimbursement commensurate with complexity of care
(4) an improved screening tool for dental school admission clinics
(5) standardized criteria for outcomes assessment and research
(6) enhanced diagnostic consistency and
(7) a simplified aid in the decision-making process associated with referral
- 3 classifications:
- Four (4) categories in each classification:
- Class I:
Class IV:
edentulous, partially edentulous, dentate
class I - class IV
an uncomplicated clinical situation
represents a complex clinical situation
Classification System for Complete Edentulism
Diagnostic Criteria
(4)
- Bone Height (mandibular)
- Residual Ridge Morphology (maxilla)
- Muscle Attachments (mandibular)
- Maxillomandibular Relation
- Hard tissues
- Soft tissues
- Maxillomandibular Relationship/Occlusion
Classification System for Complete Edentulism
* Class I —
* Class II –
* Class III -
* Class IV –
straightforward
denture-supporting anatomy degraded
anatomy degraded, surgical revision needed,
additional factors are present
most debilitated edentulous condition
Diagnostic criteria are organized by their objective nature and not in
their rank of significance.
(4)
- Bone height – mandibular only
- Residual ridge morphology – maxillary only
- Muscle attachments – mandibular only
- Maxillomandibular relationship
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* Other variables (contributing to increased difficulty):
the presence
of implants, gag reflex, tongue size, interarch space,
psychosocial conditions, systemic conditions, refractory
patient
Bone Height - Mandible only (measured at the least height)
* – mm (or greater) = Type I (most favorable)
* – mm = Type II
* – mm = Type III
* – mm (or less) = Type IV
21
16-20
11-15
10
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Muscle Attachments – Mandibular only
Effects of muscle attachment that can be difficult to quantify
* Type A:
* Type B:
* Type C:
* Type D:
* Type E:
all regions have attached mucosa without undue
impingement during function
no attached mucosa in labial vestibule; mentalis
muscle attaches near the crest of ridge
no attached mucosa in anterior lingual vestibule;
genioglossus and mentalis m. attach near ridge crest
attached mucosa only in posterior lingual region;
mucosal base detached in all other regions
no attached mucosa in any region
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Residual Ridge Morphology – Maxillary only
The most objective criterion for the maxillary arch.
* Type A:
* Type B:
* Type C:
* Type D:
Adequate vestibular depth, absence of tori, palatal morphology will
resist movement of the denture.
Posterior buccal vestibule lost, tuberosity/hamular notch poorly
defined.
Anterior labial vestibule lost, mobile anterior ridge, palatal vault offers
little resistance to movement of denture.
Anterior and posterior vestibules lost, tori interfere with posterior
border of denture, hyperplastic and mobile anterior ridge
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Maxillomandibular relationship
* Class I –
* Class II –
* Class III –
most favorable
requires tooth position outside normal
ridge and articulation for esthetics, phonetics and
articulation
requires tooth position outside normal ridge
relation for esthetics, phonetics and articulation; possible
anterior or posterior cross-bite
Class I – Maxillomandibular Relationship
Maxillomandibular relationship
allows tooth position that has
normal articulation with the
teeth supported by the residual
ridge.
Class II – Maxillomandibular Relationship
Maxillomandibular relationship
requires tooth position outside the
normal ridge relation in order to
attain phonetics and articulation
* Anterior or posterior tooth position
not supported by the residual ridge
* Anterior vertical overlap that
exceeds the principles of articulation
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Edentulous Patient Modifiers
Contribute to Increased Complexity of Treatment
(9)
- Conditions requiring pre-
prosthetic surgery - Limited interarch space
- 18-20 mm
- Moderate to severe
psychosocial considerations - Moderate/Severe oral manifestations
of systemic diseases or localized soft
tissue conditions - TMD symptoms present
- Large tongue with or without
hyperactivity - Hyperactive gag reflex
- Paresthesia or dysensthesia
- Acquired or congenital maxillofacial
defects
- Conditions requiring pre-
prosthetic surgery
(4)
- Minor/major soft tissue procedures
- Minor/major hard tissue procedures
- Implant placement (simple) – no
augmentation required or complex - Multiple extractions → complete
edentulism for immediate dentures
Class IV Complete Edentulous Patient
(4)
- Residual bone height:
least vertical height of the mandible - Class I, II and III maxillomandibular
relationship - Residual ridge offers no resistance to
horizontal or vertical movement -Maxilla - Location of muscle attachments with
significant influence on denture base
stability and retention - Mandible
Refractory pt (2)
- A patient who has chronic complaints following appropriate therapy.
- They continue to have difficulty in achieving their treatment
expectations despite the thoroughness or frequency of the treatment
provided.
Classification System for Partial Edentulism
Diagnostic Criteria
(4)
- Abutment Condition
- Occlusal Scheme
- Location / Extent Edentulous Areas
- Residual Ridge
Class I: Partial Edentulism
(4)
- Location and extent of edentulous area:
- Abutment Condition:
- Occlusion:
- Residual Ridge Morphology:
Class I: Partial Edentulism
1. Location and extent of edentulous area:
(3)
ideal or minimally compromised
edentulous area confined to a single arch and may include:
* anterior maxillary span that does not exceed 2 incisors,
* anterior mandibular span that does not exceed 4 missing incisors, or
* posterior span that does not exceed 2 premolars or 1 premolar and 1 molar
Class I: Partial Edentulism
2. Abutment Condition:
ideal or minimally compromised
no need for pre-prosthetic therapy
Class I: Partial Edentulism
3. Occlusion:
ideal or minimally compromised
no need for pre-prosthetic therapy
Class I molar and jaw relationships.
Class I: Partial Edentulism
4. Residual Ridge Morphology:
Class I Complete Edentulism description
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Biomechanical Considerations for Partial Fixed
Dental Prosthesis (FDP)
(4)
- Number of abutment teeth and number of missing teeth (simple vs complex)
- Splinted or pier abutment
- Non-parallel abutments
- Combined anterior and posterior FDP
Class I Partial Edentulism
(3)
- Ideal or minimally compromised edentulous area, abutment condition,
and occlusion - There is a single edentulous area in 1 sextant.
- The residual ridge is considered type A
Class II: Partial Edentulism
Location and extent of the edentulous area:
(4)
moderately compromised
Location: both arches have edentulous spaces and 1 of the following:
* anterior maxillary span that does not exceed 2 incisors
* anterior mandibular span that does not exceed 4 missing incisors
* posterior span that does not exceed 2 premolars or 1 premolar and 1 molar
* Any missing canine (maxillary or mandibular)
Class II: Partial Edentulism
Abutment Condition:
moderately compromised
*Insufficient tooth structure to retain or support intracoronal or extracoronal restorations – 1 or 2 sextants
*Abutments in 1 - 2 sextants require localized adjunctive therapy (minor)
Class II: Partial Edentulism
Occlusion:
moderately compromised
*Occlusion requires localized adjunctive therapy (enameloplasty – prematurities)
*Class I molar and jaw relationships are seen.
Class II: Partial Edentulism
Residual Ridge Morphology:
Class II Complete Edentulism description
Mandibular Anterior FPD
(replacing 4 incisors)
(3)
- Most common FDP to replace more than two teeth with success
- Mandibular – better prognosis than maxillary
- Direction of forces inward toward arch
- Mandibular canine teeth (optimal abutments)
- Adjacent premolar and lateral incisor are weakest potential abutments
- Maxillary FPDs supported by canines – decreased prognosis, higher
stresses/forces
Replacement of Missing Canine (PDI class 2 or higher)
* Replacement of missing canine
(3)
- Adjacent premolar and lateral incisor are weakest potential abutments
- Maxillary replacement – forces outside inter-abutment axis & directed outward
- Best restored with implant-supported single crown
Restoration of the Occlusal Plane
(2)
*Occlusal interferences produced when FDP made to over-erupted
opposing dentition.
*Opposing tooth/teeth restored to correct occlusal plane
*Opposing tooth/teeth restored to correct occlusal plane
(2)
- May require RCT; periodontal surgery; orthodontics; extraction
- Prevents occlusal interferences in restored dentition
Challenging conditions: Tilted Molars
(3)
- Generally poor abutments
- Mesial wall must be over-reduced/overtapered (↓ resistance)
- Distal adjacent tooth may intrude on the path of insertion
- Mesial surface may need re-contouring or restoration or extraction or
orthodontic uprighting
Tilted Molar Abutments: Molar Uprighting
* Molar uprighting
(3)
- Places abutment in better position for preparation
- Distributes forces under loading through long axis of tooth
(helps prevent/eliminate mesial bony defects) - Enables replacement of optimum occlusion
Tilted Molar Abutments: Non-rigid attachment
(3)
Allows slight movement - short span
* Keyway in distal of premolar to avoid intrusion of molar (mesial seating action)
* Must prepare box in distal of premolar preparation (to accommodate the female/keyway)
Non-Rigid Connectors - Indications
(3)
- Pier Abutment FPD
- Long span FPD with multiple abutments
- Non-parallel abutments – Tipped molar
Replacement / Restoration of Anterior Teeth:
Anterior Guidance
(2)
- The custom incisal guide provides a record of the incisal guidance that has
been established with provisional restorations or a diagnostic wax-up. - The custom incisal guide table provides a record for the lab to create the
desired anterior guidance in the produced prostheses
Class III Partial Edentulism
Location and extent of the edentulous area: substantially compromised
(3)
*1 or both arches; compromised support of abutment teeth
*Posterior maxillary or mandibular edentulous area > 3 teeth or 2 molars
*Any edentulous areas including anterior and posterior areas of 3 or more teeth
Class III Partial Edentulism
Abutment Condition:
(2)
substantially compromised / fair prognosis
*Insufficient tooth structure to retain or support intracoronal or extracoronal
restorations – 3 sextants
*More substantial localized adjunctive therapy (perio, endo, ortho procedures) – 3 sextants
Class III Partial Edentulism
Occlusion: substantially compromised
(2)
*Entire occlusion must be re-established, but without any change in the occlusal
vertical dimension.
*Class II molar and jaw relationships are seen
Class III Partial Edentulism
Residual Ridge Morphology:
Class III Complete Edentulism
Class III Partially Edentulous Patient
(2)
- Any edentulous areas including anterior and
posterior areas of 3 or more teeth - Maxillary canine and 2 contiguous teeth
Class III Partially Edentulous
(3)
- Edentulous area(s) are located in both arches and multiple locations within each arch.
- The abutment condition is substantially compromised due to the need for extracoronal
restorations. There are teeth that are extruded and malpositioned. - The occlusion is substantially compromised because re-establishment of the occlusal
scheme is without a change in the occlusal vertical dimension
Class IV: Partial Edentulism
Location and extent of the edentulous area:
(1)
severely compromised
*Any edentulous area or combination of edentulous areas requiring a high
level of patient compliance.
Class IV: Partial Edentulism
Abutment Condition:
(3)
severely compromised
*Abutments in 4 or more sextants have insufficient tooth structure to retain
or support intracoronal or extracoronal restorations.
*Abutments in 4 or more sextants require extensive adjunctive therapy (ie,
periodontal, endodontic, or orthodontic procedures).
*Abutments have guarded prognoses
Class IV: Partial Edentulism
Occlusion:
(2)
severely compromised
*Entire occlusion must be reestablished, including changes in the occlusal
vertical dimension.
*Class II division 2 and Class III molar and jaw relationships are seen.
Class IV: Partial Edentulism
Residual Ridge Morphology:
Class IV Complete Edentulism
Classification System for the Completely Dentate Patient
Diagnostic Criteria
(2)
- Tooth Condition
- Occlusal Scheme
Class I: Dentate patient
Tooth Condition and Occlusal Scheme
* Ideal or minimally compromised tooth condition
(2)
- Ideal or minimally compromised tooth condition
- No localized adjunctive therapy required
- Pathology that affects the coronal morphology of 3 or
less teeth; one sextant
Class I: Dentate patient
Tooth Condition and Occlusal Scheme
* Ideal or minimally compromised occlusal scheme
(3)
- No pre-prosthetic therapy required
- Contiguous, intact dental arches
- Class I molar and jaw relationships
Class II: Dentate patient
Moderately compromised tooth condition
(4)
*Insufficient tooth structure to retain or support intracoronal or extracoronal
restorations – one sextant (pin-retained core / post-core)
*Pathology that affects the coronal morphology of 4 or more teeth in a sextant
*Pathology can be in 2 sextants and can be in opposing arches
*Teeth require localized adjunctive therapy, i.e., periodontal, endodontic or
orthodontic procedure for a single tooth or in a single sextant.
Class II: Dentate patient
Moderately compromised occlusal scheme
(4)
*Occlusal scheme requires localized adjunctive therapy
- Enameloplasty on premature occlusal contacts
*Anterior guidance is intact
*Class I molar and jaw relationships
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Class II Dentate Pt
(2)
- 1 sextant exhibits 3 defective
restorations with an esthetic
component - Additional variables of gingival
architecture and individual tooth
proportions increase the
complexity of the clinical
conditions
Class III: Completely Dentate Patient
* Substantially Compromised Tooth Condition
(4)
- Insufficient tooth structure to retain or support intracoronal or extracoronal
restoration— 2 sextants - Pathology that affects the coronal morphology of 4 or more teeth in 3 or
more sextants - Pathology can be in 3 sextants in the same arch and/or in opposing arches
- Teeth require more substantial localized adjunctive therapy, i.e., periodontal,
endodontic or orthodontic procedures for teeth in 2 sextants
Class III: Completely Dentate Patient
* Substantially Compromised Occlusal Scheme
(2)
- Occlusal scheme requires major therapy to maintain the entire occlusal
scheme without any change in the occlusal vertical dimension
PDI Class IV: Completely Dentate Patient
Severely Compromised Tooth Condition
(3)
*Insufficient tooth structure to retain or support intracoronal or
extracoronal restorations – 3 or more sextants
*Pathology affects coronal morphology of ≥ 4 teeth in all sextants
*Teeth in ≥4 sextants require extensive adjunctive therapy (perio,
endo, or ortho)
PDI Class IV: Completely Dentate Patient
Severely Compromised Occlusal Scheme
(3)
*Occlusal scheme requires major therapy to re-establish the entire
occlusal scheme including any changes in the occlusal vertical
dimension
*Class II, Division 2 malocclusion
*Class III molar and jaw relationships
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Modifiers for all PDI classifications:
Increase Complexity and Classification Level
(8)
- Esthetic concerns / challenges
- Presence of TMD symptoms
- Oral manifestations of systemic disease
- Psychosocial factors
- Maxillofacial defects
- Ataxia
- Refractory Patient
How to Use the PDI classification in the Clinic
Summary of the PDI Information and Worksheets can be found in
axiUm under “Links”
Classification needs to be established in axiUm under:
(2)
- Removable Prosthodontic Consults and
- Fixed Prosthodontic Consults
