Radiopaque agent in dental composites

# What is added to increase radiopacity in composites?
A. Aluminium oxide
B. Ferric chloride
C. Boron oxide
D. Calcium sulphate

The correct answer is A. Aluminium Oxide.

Filler composition in composites are often modified with other ions to produce desirable changes in properties.
Barium, zinc, boron, zirconium, yttrium ions have been used to produce radiopacity in the filler particles.

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Highest incidence of pulp necrosis

# Highest incidence of pulp necrosis is associated with?
A. Class V Preparation on root surface
B. Inlay preparation
C. Partial veneer preparation
D. Full crown preparation

The correct answer is D. Full crown preparation.

The most intense level of frictional heat is generated with a large diamond stone when teth are prepared for a full crown. 

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Least invasive Dental treatment

# Least invasive technique for treatment of white spots on enamel?
A. Microabrasion
B. Night guard bleaching
C. Vital bleaching
D. Caries infiltrate

The correct answer is D. Caries infiltrate.

- The earliest carious lesion is termed a 'white spot' that can be active or inactive. These can be effectively treated with least invasive technique called 'Caries infiltrate'. The etching is done with HF followed by infiltration of low viscosity/high flow resins. These are mainly used in interproximal areas after removal of orthodontic bands.

- Microabrasion should be considered the first line of treatment for removing intrinsic enamel stains before more aggressive restorative options are considered. It is used for removal of fluorosis , localized hypoplasia, prosthodontic demineralization and white/brown dysmineralization. 

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Retention of Dental Composite resins

# Dental composite resin restorations are retained by:
A. Cohesion
B. True bonding
C. Mechanical interlocking
D. Atomic forces

The correct answer is C. Mechanical interlocking.

- Surface irregularities are produced by acid etching enamel with 37% to 50% phosphoric acid.
- The primer flows into these irregularities and resin tags are formed providing mechanical interlocking providing micromechanical bonding.
- The microtags formed are 2 to 5 micrometers in length.
- Bond strength is in the range of 18 to 22 MPa.
- Composites increase resistance form by bonding and strengthening tooth structure.

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