MCQs Flashcards by Rachel Sladden

When planning a veneer what must be marked? And why?

Centric, protrusive, lateral occlusal movements must be marked
This is to prevent the veneer margins coinciding with these areas. The placement of margins on occlusal marks will cause the resin to wear and the unsupported ceramic to eventually chip and break

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What is a veneer?

Thin facing fabricated either by ceramic or composite material

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5 cases a veneer could be used for

Colour defects or abnormalities i.e. amelogenesis imperfecta, medication, ﬂuorosis, age, trauma,extrinsic staining with inﬁltration of tissues
Abnormalities of shape i.e. microdontia, atypical tooth shape, retained deciduous teeth
Abnormal structure or texture i.e. dysplasia, dystrophy, erosion, attrition, abrasion, coronal fracture
Diastema
Missing teeth i.e. lateral with canine in lateral position
Correct anterior guidance or create canine guidance
Palatal erosion
Lengthening

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What is NOT needed to complete a porcelain laminate veneer?

a. Resin cement
b. Acid etched enamel
c. Dentine bonding agent
d. Porcelain veneer
e. Silane coupling agent

Dentine bonding agent

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What it is the signiﬁcance of the foil in the foil based technique for the production of a veneer?

Creates space for the cement

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When is the ‘window’ preparation useful?

Canine guidance

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List 3 indications for placing a crown

trauma, heavily broken down teeth, hypoplastic conditions, alter occlusion, restore missing function, appearance

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When planning for crowns, what important points would are important to make the patient aware of?

Destructive prep and natural tooth tissue will be lost
Pulpal exposure- especially if younger
Complex procedure- time and patient cooperation needed
Maintenance and good OHI necessary

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List 3 contraindications for placing a crown

other more conservative restorative options, poor OH, extensive caries, periodontal condition

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What patient factors must we take into considerations when planning for crowns?

Patient cooperation
Age- young have large pulp chambers, old have brittle teeth
Cost
Social history
Importance of aesthetics to patient
Patients expectations.
Patient OH

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Which of these is not a desirable feature for an inlay & onlay preparation

a. Divergent walls
b. Undercut
c. Rounded internal line angles
d. Margins within enamel

B - undercut

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Which of these factors is not a contraindication for the provision of inlays & onlays.

a. Poor oral hygiene
b. Patient with parafunctional bruxist habits
c. Small clinical crown
d. Fractured tooth

C - small clinical crown

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Which of the these is not a material used for inlay & onlays construction

a. Gold
b. Stainless steel
c. Resin composite
d. Ceramic

B - stainless steel

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Give three advantages of using a gold inlay to restore a tooth

Excellent longevity
 Does not abrade opposing teeth
 Does not disclour over time
 Does not wear over time
 Corrosion resistance
 Coefficient of expansion is similar to the tooth
Biocompatible

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What are the four main stages involved with restoring a tooth with an inlay/onlay

Tooth preparation
Impression with elastomeric material
Temporary restoration
Cement final restoration

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List the properties of composite fillers (5)

Alters properties and behaviours of materials
Reduce polymerisation shrinkage
Reduce fracture propagation
Increase wear resistance
Improve optical properties

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What are the unwanted interactions between materials in a compound system? (3)

Electromechanical corrosion
Mismatch thermal expansion interface damage
Unstable dimensional form

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Explain the mutualistic relationship in a compound system with an example? (5)

Porcelain bonded to metal crowns
-optical properties achieved with porcelain
-metal substructure counters fracture propagation mechanism of porcelain
-metal occlusal contacts bear side impacts
Glass-infiltration strengthens alumina matrix
-feldspathic porcelain bonded to substrate provides optical properties

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Which of the following is not an example of a compound system?
A.	Beta quartz inserts in composite
B.	Ceramic to dentine
C.	Composite bonded to ionomers
D.	Porcelain bonded to alumina

B - ceramic to dentine

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Which of the following is NOT a way of joining materials in a compound system?
A.	Sand-blasting
B.	Mechanical interlocking
C.	Moulding around base material
D.	Welding

A - sand-blasting

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Why are endodontically treated teeth compromised?a. Reduced tensile strength following reduced blood flow, loss of structural integrity following loss of roof of the pulp chamber

b. Loss of dentine elasticity
c. Reduce compressive strength following reduced blood flow, loss of structural integrity following loss of roof of the pulp chamber
d. Reduced tensile strength following access cavity preparation, loss of integrity of the surrounding periodontium, weakened tooth due to access cavity preparation.

B - loss of dentine elasticity

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Choose the most appropriate answer regarding high strength core-ceramic posterior crowns.

a. In preparing the tooth, ceramic margins should be a butt-joint rounded shoulder.
b. A systematic review demonstrated that premolar crowns have a higher five-year fracture rate than molar crowns.
c. All high strength ceramics should have a chamfer margin with one-millimetre in width.
d. Resistance prevents displacement of the crown in the antero-posterior direction.

A - shoulder margins

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Read the following statements and choose which of the following constitute Phase II of the clinical stages of posterior crowns.

I. Tooth build-up and preparation
II. Removal of temporary crown
III. Temporisation
IV. Occlusal Record
V. Diagnostic Wax-Up
VI. Informed consent

a. V and VI
b. I and V
c. II, IV and V
d. I, III and IV

D - I, II, IV

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A 32-year old male has agreed to restore his upper left first premolar with a porcelain-fused-to-metal crown. He is particularly interested in the types of alloys. Upon discussion, he discovers that there is a small amount of tin and iron in the alloy.
i. What is the most likely type of PFM alloy? (1)

ii. Why is tin and iron present in the alloy? (2)

i. High-noble alloys

ii. Provides a layer for oxide formation, provides a chemical bond for the porcelain to metal

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What is the evidence for the high five-year survival-rate of all-ceramic crowns? (2)

Pjeturrson et al. 2007

What are the functions of temporary crowns?

``` To protect the pulp For marginal integrity Allow healing of soft tissues after implant surgery Provide adequate aesthetics Facilitate plaque control To maintain or rebuild occlusion ```

What two features of the prep can be picked up from temporaries?

Undercuts - when temp is locked in place | Under-prep - tearing/ perforation of the temporary

Difference between reorganised occlusion and conformative temporary crowns?

Reorganised occlusion used to increase vertical dimension with help of diagnostic wax-up Conformative temp maintains height of prepared tooth

List the consequences of failed temporaries

Pain Overeruption Drifting of teeth Damage to core prep

List the types of temporary crowns and give examples for each

Direct - GIC Pre fabricated crowns - SS used in paeds Custom made - ProTemp Composite resin - laminate veneers

Which of the following are not done at the review stage? a. Check for new disease b. Temporise any teeth that need it c. Determine recall periods d. Check adequacy of restorations

B - temporise any teeth that need it

What material can you use to repair a hole made in a crown for RCT? a. Composite b. GIC c. Amalgam d. All of the above

D - all of the above

What should you plan for when prognosis is guarded? a. Further treatment b. Change in treatment plan c. Failure d. Continuous consent

C - failure

Name 3 types of technical failure

``` Fractured restorations Marginal breakdown Tooth fracture Defective contour Appearance Retention failure ```

How would you manage loss of retention of a crown?

Assess cause of failure Clean tooth Repair with cementation -optional: you can use mechanical locking with pins and undercuts

In which of these situations is the coefficient of thermal expansion ideal for a PFM crown? a. The coefficient of thermal expansion of the porcelain is higher than that of the metal. b. The coefficient of thermal expansion is the same for both. c. The coefficient of thermal expansion of the metal is higher than that of the porcelain. d. Coefficient of thermal expansion does not matter for the materials when making a PFM.

C - the coefficient of thermal expansion of the metal is higher than that of the porcelain

What effect does increasing the copper content have on the properties of a high gold alloy? a. Increases the yield stress and so increases the plastic deformation of the alloy. b. Decreases the yield stress and so increases the plastic deformation of the alloy. c. Increases the yield stress and so decreases the plastic deformation of the alloy. d. Decreases the yield stress and so decreases the plastic deformation of the alloy.

C - increases the yield stress and so decreases the plastic deformation of the alloy

When deciding on the shade for a crown, what sequence should you take? a. Decide on the chroma, then value, then hue. b. Decide on the hue, then chroma, then value. c. Decide on the chroma, then hue, then value. d. Decide on the value, then chroma, then hue.

D - VCH

These are all indications of a veneer besides one, which one? a. Amelogenesis imperfecta b. Microdontia c. Bruxism d. Coronal fracture

C - bruxism

For which of the following incisor relationships would a veneer window preparation be useful: a. Class I b. Class II division I and Class II division II c. Class III and Class II division I d. Class III and Class II division II

D - class III and class II div 2

What is 'value' the measurement of when shade taking for crowns? a. Colour family b. Colour Saturation c. Colour Translucenecy d. Lightness

D - lightness

Which of the following situations is most suitable for veneers: a. Midline diastema in a bruxist patient b. Midline diastema in a patient with poor oral hygiene c. Midline diastema with fluorosis affecting the upper centrals d. Midline diastema where teeth are outstandingly triangular

C - midline diastema in patient with fluorosis affecting upper centrals

Which of the following is a contraindication to placing labial veneers : a. Patient has amelogenesis imperfecta b. Pulpless teeth c. Retained deciduous teeth d. Diastema

B - pulpless teeth

Which of these is not 1 of the 5 principles of tooth preparation for crowns? a. Retention b. Reduction c. Structural durability d. Resistance

B - reduction

What percentage of gold does a typical Type III alloy contain? (used for all-metal crowns and bridges) a. 85% b. 60% c. 75% d. 90%

C - 75%

How long can laboratory-made temporaries last for (crowns)? a. 1-3 weeks b. 4-6 weeks c. 7-9 weeks d. No evidence available to prove it

B - 4-6 weeks

Which of the following is a contraindication for veneers? a. Atypical tooth shape b. Tooth erosion c. Bruxism d. Amelogenesis Imperfecta

C - bruxism

Why place a glaze on ceramic indirect restorations? a. Improve aesthetics b. Makes restorations more hygienic c. Helps to prevent the restoration from fracturing d. All of the above

D - all of the above

What material is Protemp II (3M Espe) made of? a. Polymethyl methacrylate b. Vinyl methacrylate c. Bis-GMA composite d. Bis-acryl composite

D - bis-acryl composite

4 features of suspected abscess

Red Hot Painful Swollen

Difference between periapical abscess and lateral periodontal abscess?

Periapical: vertical TTP, may be mobile, loss of lamina dura at apex, non-vital Lateral: lateral TTP, usually mobile, loss of alveolar crest, vital, pus in pocket, deep pocket

5 indications of composite

* Polychromatic conformative restoration * Alter morphology * Repair failed composite/ceramic * Occlusal rehabilitation * Tooth splinting

Advatages of using a polychromatic layered composite over ceramic veneer

* Wear is similar to tooth structure * Can be constructed at chairside * Chairside repairs * Little/No tooth preparation

3 components of a direct composite

Resin Filler Coupling agent

3 temporary crown materials - custom made - prefabricated - direct

Acetate (ProTemp) Polycarbonate shell (Directa) Stainless steel shell

6 functions of a temporary crown

* Facilitate good plaque control * Marginal integrity of tooth * Maintain occlusal function * Protect dentine and pulp * Positional stability * Shape soft tissues after implant placement * Aesthetics

Pt comes in with a loose temp crown, how would you manage?

* Assess cause of failure – when and how * Check prep and temp * Recement if ok, or use adhesive luting agent if not * Clean tooth surfaces before

28 year old rugby player comes to you with fractured upper right incisor, fracture extends into dentine, you choose to do a resin bonded crown, patient wants crown to be aesthetically good, and inconspicuous. -What would you send to the lab in order to get good aesthetics, and how would you communicate this? (8)

* Impression of preparation * Impression of opposite arch to take into account the occlusion * Photograph before fracture – good shade indicator * Photograph of adjacent teeth * Desired material for crown * Shape * Colour * Surface Texture * Translucency * Written Description

How are resin bonded ceramics different to other indirect restorations?

- Minimal preparation of the tooth - Tooth is core structure - Good aesthetics – translucency and tooth showing through - Cementation via an aesthetic dual cure resin

Prescribing for a patient with toothache

``` Ibuprofen: 2 x 400mg TDS Paracetamol: 2 x 500mg QDS (not exceeding 4g/ 24hrs) Co-codamol: 2 x 500mg QDS -8/500 and 15/500 preparations OTC -30/500 must be prescribed ```

Define hue, value and chroma

Hue is described with the words we normally think of as describing color: red, purple, blue, etc. Value (lightness) describes overall intensity to how light or dark a color is. It is the only dimension of color that may exist by itself. Chroma (saturation) may be defined as the strength or dominance of the hue.

Pulp vitality and crowns

15-20% go non-vital

5 advantages of composite over GIC

1. Better wear resistance (similar to tooth structure) 2. Better aesthetics - shade match 3. Better bond to tooth structure 4. Better polishability 5. Command set - longer working time

Temporary Restorations – loose temp management (3), reasons why it’s loose (4), types of temp for posterior (3), 6 functions (6)

Management: remove crown, assess cause, check preparation, correct, recement if cause corrected Reasons: marginal integrity, prep too thin, incorrect cement strength, solubility of cement, poor technique e.g. not under moisture control Posterior: preformed metal crown, ProTemp, Snap Functions: aesthetics, diagnosis, space maintainer, mastication, facilitate plaque control, protection, assess tooth reduction, provide coronal seal between RCT appointments, assess prognosis, control/ customise emergence profile

Indications for use of GIC

1. Base and liner 2. Temporary restoration 3. Restoration with poor moisture control e.g. in children 4. Cementing crowns 5. Sealing endo access cavity 6. Blocking out undercuts 7. Fissure sealants in indicated teeth 8. Abrasion and erosion lesions 9. Class III lesions with exposed dentine 10. Atraumatic restorative treatment

6. Ceramics – 3 types (3), how substructure affects (6), dentine bonding precautions (5)

Types: alumina, zirconia, glass ceramics e.g. lithium disilicate Feldspathic ceramic is weak, can be supported by metal substructure, high strength ceramic core or if bonded to the tooth it uses tooth as substructure Precautions: weak so only use in anterior region, refractory model production may compound errors, fragile restoration (especially margins) due to lack of supporting structure ENSURE YOU HAVE MOISTURE CONTROL, DO NOT DESSICATE TOOTH, ENSURE YOU HAVE ACID ETCHED, ENSURE YOU DON'T GET BOND ON ADJACENT TEETH, CARE WITH DRYING

Components of composite

``` Filler: silica (SiO2) Matrix: bisGMA Photoinitiator -HEMA -UDMA -TEGDMA -most commonly camphorquinone ```

Amalgam failure most commonly due to

Tooth fracture

Setting reaction of zinc polycarboxylate

Cross-linking to form a salt (acid-base reaction)

Buccal width of a PFM

1.2-1.4mm

4 principle dentine adhesive systems

3 stage system: etch with dentine conditioner (phosphoric acid), prime with bifunctional monomer, seal with unfilled resin -drying makes this technique sensitive Etch and rinse, then prime and seal e.g. Scotchbond 1 -have to dry -worse bond Self-etching primers e.g. Clearfil SE bond -etch and prime with acidic monomer, then bond -no drying gives more consistent results -weak etching of enamel can lead to marginal staining All-in-one system e.g. XenoIII -simplest system but weakest bond strength

Reaction to amalgam on soft tissues adjacent

Lichenoid

What happens if the CSA of amalgam is reduced?

Enamel margin fracture

Which class of cavity does C factor affect the most?

Class 1

AgP affects which cell?

Polymorphonucleocyte

List 3 ways you can bond composite to precious metal

Metal primers Silica coating Tin plating

Which 3 materials can you use as a high strength core in ceramic restorations

Zirconia Alumina Spinnel