Dental Materials and Temporary Restorations Quiz

Class IV Cavity Preparation

• Involves proximal surface of anterior teeth, including the incisal edge.
• Conventional, beveled conventional, and minimally invasive preparations are described.
• Initial steps involve preparing a class III cavity mesially, using a diamond round bur.
• The class III cavity is then transformed into a class IV cavity by extending it incisally.
• Incisal edge is removed using a fissure bur with oblique reduction.
• Buccal enamel is beveled using a flame-shaped bur (0.5-1mm bevel).

Treatment of Crown Fractures of Anterior Teeth

• Fractures can be enamel, crown without pulp involvement, and crown with pulp involvement.
• Fracture type classification involves 6 types (1 - 6) and 9 squares. Class 1 is 1 or less, Class 2 ≤ 2.5, and 3-6 are extensive involving 3 to 6+ squares.
• Class 1 - loss of 1 unit or less of tooth structure (distal or mesial edge)
• Class 2 - loss of tooth structure not exceeding 2 squares (distal or mesial edge)
• Class 3 - loss of tooth structure not exceeding 2.5 squares covering 2/3 of incisal edge
• Class 4 - extensive fracture (at least 3 squares covering 2/3 of incisal edge)
• Class 5 - fracture covering 3 squares containing full incisal edge
• Class 6 - fracture covering 6 squares containing full incisal edge

Cervical Lesions

• Can be carious or non-carious.
• Classification based on anatomy and etiology (carious crown only, crown and root, only root).
• Non-carious cervical lesion (NCCL) is a broad term for wear, erosion, abfraction, and abrasion.

Cavity Varnish, Liner, and Base

• Preserves dental pulp health, prevents irritation (chemical, thermal, and mechanical).
• Used for medium and deep preparations (into dentin): varnish and liner, or cavity liner and base.
• Varnish is not used under composite.
• Varnish, liner, and base materials are incompatible with composites and block adhesion.

Temporary Restorations

• Aim is to save the prepared tooth surface and involve the tooth in function or release it from loading.
• Minimize possibility of fracture, drift or gingival growth into the cavity.
• Used in urgency, time-consuming treatment, multiple appointments or as needed for laboratory work, or treatment of pulp, separation, root canal treatment, walking bleach, prosthetic, or orthodontic treatment.

Amalgam (Dental Amalgam)

• An alloy of mercury with other metals (e.g., silver, tin, copper, zinc).
• Has properties such as volumetrical stability, non-toxicity, mechanical resistance, ductility, thermal conductivity, electrical conductivity, and corrosion resistance.
• Different types of amalgam can have different compositions and properties.

Composites (Resin-based Materials)

• Classify composites by their consistency (flowable/compactable).
• Classify by layer thickness (liners, layered, bulk-fill).
• Classify by polymerization type (self-curing, light-curing, dual-curing).
• Key components are organic matrix, inorganic filler particles and the coupling (binding) phase silane.
• Monomers like BIS-GMA, UDMA, TEGDMA link to form a cross-linked polymer structure which is initiated by light.

Glass-ionomer cements(GIC)

• Involve an acid-base reaction forming a polyalkenoate cement.
• Composed of a liquid matrix and a powdered filler.
• Filler particles are reactive silicate glasses (i.e., Ca-Al-F silicate glass and/or Sr-Al-F silicate glass)