Teeth least affected with the nursing bottle syndrome

 # Which teeth are least affected with the nursing bottle syndrome?

A. Maxillary molars

B. Maxillary and mandibular canines

C. Mandibular incisors

D. Maxillary incisors

The correct answer is C. Mandibular incisors.

EARLY CHILDHOOD CARIES

Early childhood caries was historically attributed to inappropriate and prolonged use of sweetened liquid in the bottle. Hence the older terms of “baby-bottle tooth decay” and “nursing caries. Early caries involvement of the maxillary anterior teeth, the maxillary and mandibular posterior teeth and mandibular canines is seen.

FEATURES:

• Mandibular incisors are unaffected due to the protection by the tongue.

• Seen as white or dark brown collar of caries around the neck o f the incisors, which develops into

faciolingual caries and may also fracture the tooth.

• The main etiology is that the child is put to bed with a nursing bottle containing milk or sugar containing beverages. The child falls asleep and the milk or sweetened liquid becomes pooled around the maxillary anterior teeth. This provides an excellent culture medium for acidogenic microorganisms.

Salivary flow is reduced during sleep and clearance of the liquid from the oral cavity is slowed.

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Maxillary second primary molar with a necrotic pulp

 # A healthy six year old child presents with carious maxillary second primary molar with a necrotic pulp. Which treatment would be preferred?

A. Extraction

B. Indirect pulp treatment

C. Pulpotomy

D. Pulpectomy

The correct answer is D. Pulpectomy.

PULPECTOMY: “Removal of the entire pulp and subsequent filling of the canals of the primary teeth with a suitable resorbable material.”

INDICATIONS

1. Primary teeth with pulp inflammation extending beyond the coronal pulp

2. Roots and alveolar bone with minimum pathologic resorption

3. Primary teeth with necrotic pulp and or periapical abscess

4. Pus at the clinical pulp exposure site.

CONTRAINDICATIONS

1. Grossly destroyed tooth that is nonrestorable clinically

2. Periradicular involvement extending to the permanent tooth bud, where the risk of damage to the permanent tooth is high.

3. Root resorption—internal or external

4. Extensive mobility

5. Gross bone loss at the apex or at the furcation.

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Crowns of all the permanent teeth, with the exception of the third molars, are calcified by the age of:

 # The crowns of all the permanent teeth, with the exception of the third molars, are calcified by the age of:

A. 6 years

B. 8 years

C. 10 years

D. 12 years

The correct answer is B. 8 years.

Reference: First AID for NBDE Part 1, 3rd edition 2012, Page 660

Most effective method of preventing dental decay

 # Which of the following is the most effective method of preventing dental decay in general population?

A. Oral prophylaxis

B. Systemic fluorides

C. Diet counseling

D. Fluoride mouth wash and toothpaste

The correct answer is D. Fluoride mouthwash and toothpaste.

 The most effective strategy for prevention of caries has been increasing tooth resistance through the use of systemic and topical fluorides. Systemic and topical fluoride application has been deemed by many researchers to be the single most important preventive and treatment modality older adults can employ to prevent dental caries. The concentration and the method and frequency of application

depend on the level of risk and the ability of the individual to manage the regimen.

Reference: Jong's Community Dental Health, 5th edition , Page no 144

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Space lattice refers to:

 # Space lattice refers to:

A. Inter atomic movement

B. Inter atomic imbalance

C. Arrangement of atoms

D. Arrangement of molecules

The correct answer is C. Arrangement of atoms.

A space lattice can be defined as any arrangement of atoms in space in which every atom is situated similarly to every other atom.

Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 20

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Which of the following bonds is responsible for thermal conduction?

 # Which of the following bonds is responsible for thermal conduction?

A. Ionic bond

B. Van der Waal bond

C. Metallic bond

D. Covalent bond

The correct answer is C. Metallic bond.

The free electrons give the metal its characteristically high thermal and electrical conductivity. These electrons absorb light energy, so that all metals are opaque to transmitted light. The metallic bonds are also responsible for the ability of metals to deform plastically. The free electrons can move through the lattice, whereas their plastic deformability is associated with slip along crystal planes. During slip deformation, electrons easily regroup to retain the cohesive nature of the metal.

Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 19

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Atomic bonds characterized by physical forces

 # Which of the following atomic bonds are characterized by physical forces?

A. Ionic bonds

B. Van der Waal bonds

C. Metallic bonds

D. Covalent bonds

The correct answer is B. van der Waals bonds

van der Waals forces—Short-range force of physical attraction that promotes adhesion between

molecules of liquids or molecular crystals.

Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, Anusavice, Shen, Rawls, 12th Edition, Page No: 17

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