PDI

Question 1

Dentistry uses many classification systems
* Despite challenges (not always applicable, agreement not always present…)
* Examples
(3)

Answer 1

• ASA
• Kennedy’s classification of edentulous space and Applegate’s rules
• Other disciplines have classification systems

Question 2

Main Advantage:
* Comprehensive evaluation and Assessment of all necessary parameters to help in
(3)

Answer 2

Diagnosis, Treatment, and Prognosis

Question 3

SKIPPED
Prosthodontic Diagnostic Index (PDI)
Potential benefits of the system include:
(7)

Answer 3

(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

Question 4

• 3 classifications:
• Four (4) categories in each classification:
• Class I:
  Class IV:

Answer 4

edentulous, partially edentulous, dentate
class I - class IV
an uncomplicated clinical situation
represents a complex clinical situation

Question 5

Classification System for Complete Edentulism
Diagnostic Criteria
(4)

Answer 5

1. Bone Height (mandibular)
2. Residual Ridge Morphology (maxilla)
3. Muscle Attachments (mandibular)
4. Maxillomandibular Relation

• Hard tissues
• Soft tissues
• Maxillomandibular Relationship/Occlusion

Question 6

Classification System for Complete Edentulism
* Class I —
* Class II –
* Class III -
* Class IV –

Answer 6

straightforward
denture-supporting anatomy degraded
anatomy degraded, surgical revision needed,
additional factors are present
most debilitated edentulous condition

Question 7

Diagnostic criteria are organized by their objective nature and not in
their rank of significance.
(4)

Answer 7

• Bone height – mandibular only
• Residual ridge morphology – maxillary only
• Muscle attachments – mandibular only
• Maxillomandibular relationship

Question 8

SKIPPED
* Other variables (contributing to increased difficulty):

Answer 8

the presence
of implants, gag reflex, tongue size, interarch space,
psychosocial conditions, systemic conditions, refractory
patient

Question 9

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

Answer 9

21
16-20
11-15
10

Question 10

SKIPPED
Muscle Attachments – Mandibular only
Effects of muscle attachment that can be difficult to quantify
* Type A:
* Type B:
* Type C:
* Type D:
* Type E:

Answer 10

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

Question 11

SKIPPED
Residual Ridge Morphology – Maxillary only
The most objective criterion for the maxillary arch.
* Type A:
* Type B:
* Type C:
* Type D:

Answer 11

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

Question 12

SKIPPED
Maxillomandibular relationship
* Class I –
* Class II –
* Class III –

Answer 12

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

Question 13

Class I – Maxillomandibular Relationship

Answer 13

Maxillomandibular relationship
allows tooth position that has
normal articulation with the
teeth supported by the residual
ridge.

Question 14

Class II – Maxillomandibular Relationship

Answer 14

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

Question 15

SKIPPED
Edentulous Patient Modifiers
Contribute to Increased Complexity of Treatment
(9)

Answer 15

• 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

Question 16

• Conditions requiring pre-
  prosthetic surgery
  (4)

Answer 16

• 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

Question 17

Class IV Complete Edentulous Patient
(4)

Answer 17

• 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

Question 18

Refractory pt (2)

Answer 18

• 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.

Question 19

Classification System for Partial Edentulism
Diagnostic Criteria
(4)

Answer 19

1. Abutment Condition
2. Occlusal Scheme
3. Location / Extent Edentulous Areas
4. Residual Ridge

Question 20

Class I: Partial Edentulism
(4)

Answer 20

1. Location and extent of edentulous area:
2. Abutment Condition:
3. Occlusion:
4. Residual Ridge Morphology:

Question 21

Class I: Partial Edentulism
1. Location and extent of edentulous area:
(3)

Answer 21

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

Question 22

Class I: Partial Edentulism
2. Abutment Condition:

Answer 22

ideal or minimally compromised
no need for pre-prosthetic therapy

Question 23

Class I: Partial Edentulism
3. Occlusion:

Answer 23

ideal or minimally compromised
no need for pre-prosthetic therapy
Class I molar and jaw relationships.

Question 24

Class I: Partial Edentulism
4. Residual Ridge Morphology:

Answer 24

Class I Complete Edentulism description

Question 25

SKIPPED Biomechanical Considerations for Partial Fixed Dental Prosthesis (FDP) (4)

Answer 25

* Number of abutment teeth and number of missing teeth (simple vs complex) * Splinted or pier abutment * Non-parallel abutments * Combined anterior and posterior FDP

Question 26

Class I Partial Edentulism (3)

Answer 26

* 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

Question 27

Class II: Partial Edentulism Location and extent of the edentulous area: (4)

Answer 27

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)

Question 28

Class II: Partial Edentulism Abutment Condition:

Answer 28

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)

Question 29

Class II: Partial Edentulism Occlusion:

Answer 29

moderately compromised *Occlusion requires localized adjunctive therapy (enameloplasty – prematurities) *Class I molar and jaw relationships are seen.

Question 30

Class II: Partial Edentulism Residual Ridge Morphology:

Answer 30

Class II Complete Edentulism description

Question 31

Mandibular Anterior FPD (replacing 4 incisors) (3)

Answer 31

* 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

Question 32

Replacement of Missing Canine (PDI class 2 or higher) * Replacement of missing canine (3)

Answer 32

* 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

Question 33

Restoration of the Occlusal Plane (2)

Answer 33

*Occlusal interferences produced when FDP made to over-erupted opposing dentition. *Opposing tooth/teeth restored to correct occlusal plane

Question 34

*Opposing tooth/teeth restored to correct occlusal plane (2)

Answer 34

* May require RCT; periodontal surgery; orthodontics; extraction * Prevents occlusal interferences in restored dentition

Question 35

Challenging conditions: Tilted Molars (3)

Answer 35

* 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

Question 36

Tilted Molar Abutments: Molar Uprighting * Molar uprighting (3)

Answer 36

* 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

Question 37

Tilted Molar Abutments: Non-rigid attachment (3)

Answer 37

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)

Question 38

Non-Rigid Connectors - Indications (3)

Answer 38

* Pier Abutment FPD * Long span FPD with multiple abutments * Non-parallel abutments – Tipped molar

Question 39

Replacement / Restoration of Anterior Teeth: Anterior Guidance (2)

Answer 39

* 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

Question 40

Class III Partial Edentulism Location and extent of the edentulous area: substantially compromised (3)

Answer 40

*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

Question 41

Class III Partial Edentulism Abutment Condition: (2)

Answer 41

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

Question 42

Class III Partial Edentulism Occlusion: substantially compromised (2)

Answer 42

*Entire occlusion must be re-established, but without any change in the occlusal vertical dimension. *Class II molar and jaw relationships are seen

Question 43

Class III Partial Edentulism Residual Ridge Morphology:

Answer 43

Class III Complete Edentulism

Question 44

Class III Partially Edentulous Patient (2)

Answer 44

* Any edentulous areas including anterior and posterior areas of 3 or more teeth * Maxillary canine and 2 contiguous teeth

Question 45

Class III Partially Edentulous (3)

Answer 45

* 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

Question 46

Class IV: Partial Edentulism Location and extent of the edentulous area: (1)

Answer 46

severely compromised *Any edentulous area or combination of edentulous areas requiring a high level of patient compliance.

Question 47

Class IV: Partial Edentulism Abutment Condition: (3)

Answer 47

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

Question 48

Class IV: Partial Edentulism Occlusion: (2)

Answer 48

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.

Question 49

Class IV: Partial Edentulism Residual Ridge Morphology:

Answer 49

Class IV Complete Edentulism

Question 50

Classification System for the Completely Dentate Patient Diagnostic Criteria (2)

Answer 50

1. Tooth Condition 2. Occlusal Scheme

Question 51

Class I: Dentate patient Tooth Condition and Occlusal Scheme * Ideal or minimally compromised tooth condition (2)

Answer 51

* Ideal or minimally compromised tooth condition * No localized adjunctive therapy required * Pathology that affects the coronal morphology of 3 or less teeth; one sextant

Question 52

Class I: Dentate patient Tooth Condition and Occlusal Scheme * Ideal or minimally compromised occlusal scheme (3)

Answer 52

* No pre-prosthetic therapy required * Contiguous, intact dental arches * Class I molar and jaw relationships

Question 53

Class II: Dentate patient Moderately compromised tooth condition (4)

Answer 53

*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.

Question 54

Class II: Dentate patient Moderately compromised occlusal scheme (4)

Answer 54

*Occlusal scheme requires localized adjunctive therapy - Enameloplasty on premature occlusal contacts *Anterior guidance is intact *Class I molar and jaw relationships

Question 55

SKIPPED Class II Dentate Pt (2)

Answer 55

* 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

Question 56

Class III: Completely Dentate Patient * Substantially Compromised Tooth Condition (4)

Answer 56

* 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

Question 57

Class III: Completely Dentate Patient * Substantially Compromised Occlusal Scheme (2)

Answer 57

* Occlusal scheme requires major therapy to maintain the entire occlusal scheme without any change in the occlusal vertical dimension

Question 58

PDI Class IV: Completely Dentate Patient Severely Compromised Tooth Condition (3)

Answer 58

*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)

Question 59

PDI Class IV: Completely Dentate Patient Severely Compromised Occlusal Scheme (3)

Answer 59

*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

Question 60

SKIPPED Modifiers for all PDI classifications: Increase Complexity and Classification Level (8)

Answer 60

* Esthetic concerns / challenges * Presence of TMD symptoms * Oral manifestations of systemic disease * Psychosocial factors * Maxillofacial defects * Ataxia * Refractory Patient

Question 61

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)

Answer 61

* Removable Prosthodontic Consults and * Fixed Prosthodontic Consults