MJDF Restorative Dentistry Principles 2

Question 1

Which of the following BEST describes the 'biologic width' in relation to crown preparation and restoration placement?

Accepted Answer

The combined dimension of junctional epithelium and connective tissue attachment above the alveolar crest, approximately 2mm, which must not be violated by restoration margins

Answer

The minimum thickness of enamel required beneath a crown preparation

Answer

The space required between two crowns to allow proper flossing access

Answer

The minimum width of the gingival margin required before crown lengthening

Question 2

What is the MAIN advantage of using glass ionomer cement (GIC) as a restorative material in primary (deciduous) teeth?

Accepted Answer

GIC releases fluoride ions, promotes chemical bonding to tooth structure, and is biocompatible, reducing secondary caries risk

Answer

Glass ionomer cement has the highest compressive strength of all restorative materials

Answer

GIC is tooth-coloured and indistinguishable from natural tooth structure on close inspection

Answer

GIC bonds to all restorative materials and is ideal as a base under amalgam in primary teeth

Question 3

A patient presents with a fractured upper central incisor. The fracture line extends through enamel and dentine but does not involve the pulp. What is this classified as and how should it be managed?

Accepted Answer

Ellis Class II fracture — requires dentine protection and restoration with composite resin bonding, with monitoring of pulp vitality

Answer

Ellis Class IV fracture — requires immediate root canal treatment

Answer

Ellis Class I fracture — only enamel is involved and no treatment is necessary

Answer

Complicated crown fracture — requires emergency extraction

Question 4

What is the purpose of 'matrix bands and wedges' during the placement of a Class II composite restoration?

Accepted Answer

To create a temporary wall replacing the missing tooth surface, provide contact point formation, and prevent gingival flash of composite material

Answer

To provide anaesthesia to the adjacent teeth during cavity preparation

Answer

To protect the pulp from thermal damage during light curing

Answer

To assist in the removal of excess composite after curing

Question 5

Which of the following describes the SMEAR LAYER in the context of dentine bonding?

Accepted Answer

A thin layer of amorphous debris (cut dentine, bacterial remnants) deposited on dentine surfaces during preparation that must be either removed or modified for optimal bonding

Answer

A protective biofilm on the enamel surface that must be preserved

Answer

The outermost layer of intact dentine that provides the main bonding surface

Answer

A calcium-rich zone that forms the basis of the bonding mechanism

Question 6

When providing a complete upper denture for an edentulous patient, which anatomical landmark defines the POSTERIOR limit of the upper denture base?

Accepted Answer

The vibrating line (fovea palatinae), marking the junction between the hard and soft palate

Answer

The retromolar pad

Answer

The pterygomandibular raphe

Answer

The posterior limit of the hard palate bony shelf