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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Fish net pattern in Pemphigus Vulgaris

# Fish Net pattern in pemphigus vulgaris is seen in which of the following tests?
a) Direct immunofluorescence
b) Tzanck smear
c) FNAC
d) Histopathology

The correct answer is A. Direct immunofluorescence.

Pemphigus vulgaris causes intraepithelial bullae formation and results in loss of cohesiveness or acantholysis. Due to this, clumps of epithelial cells are found lying free in the vesicular space, known as Tzanck cells. These changes are seen in cytological smears also known as the Tzanck smear or Tzanck test. The fluid in most vesicles has scarce inflammatory cell infiltration.

Direct Immunofluorescence predominantly demonstrates the presence of IgG in combination with IgM, IgA, C3. Direct Immunofluorescence reveals a typical fish net pattern or chicken wire pattern of IgG antibodies against desmoglein 1 or 3 even in the perilesional skin.

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Elevators on Exodontia

# Most of the elevators used in exodontias work on the principle of:
A. Class I lever
B. Class II lever
C. Class III lever
D. Wheel and axle

The correct answer is A. Class I lever

Most of the elevators used are class I or simple levers. The fulcrum (alveolar bone) is located between the applied force (hand of the operators) and the load or resistance (tooth).

Effort arm (distance between the fulcrum and the force applied) should be greater than resistance arm (distance between the fulcrum and the load or resistance i.e. Tooth).

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Rh hump is seen in:

# Rh hump is seen in which portion of a tooth?
A. Cementum
B. Enamel
C. Dentin
D. Alveolar bone

The correct answer is B. Enamel.

In Erythroblastosis fetalis, there is deposition of bilirubin pigment in the enamel and dentin of developing teeth giving them a green, brown or blue hue.

In some cases, enamel hypoplasia involving the incisal edges of anterior teeth and middle third of deciduous cuspid and first molar may be seen resulting in a characteristic ring like defect known as 'Rh hump'.

No treatment for tooth pigmentation is necessary since it affects the deciduous teeth and presents only a temporary cosmetic problem.

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Interstitial pneumonia is caused by:

# Interstitial pneumonia is caused by:
A. Virus and Rickettsia
B. Fungus and bacteria
C. Rickettsia and bacteria
D. Virus and bacteria

The correct answer is A. Virus and Rickettsia.

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Osteotome vs Chisel

# Osteotomes differ from chisel in that they are:

A. Monobevelled

B. Bibevelled

C. Tetrabevelled

D. Not contain any bevels

The correct answer is B. Bibevelled. 

Chisel: Chisel are unibevelled instruments for cutting bone. The edge of the working tip has bevel on one side. The working edge is sharp and is flat. To plane bone, the bevel is kept facing away from the bone. 

Osteotome: Is similar to chisel, but the edge of the working tip is bibevelled. It splits bone rather than cut or chip the bone as with chisel. 

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Pathology of Blood Cells - General Pathology MCQs

# Which of the following is a nutritional deficiency anemia?
A. Aplastic anemia
B. Sickle cell anemia
C. Spherocytosis 

D. Megaloblastic anemia

# Megaloblastic anemia is related to:
A. Folic acid and vitamin B12 deficiency
B. Iron deficiency
C. Vitamin C deficiency
D. Vitamin K deficiency

# Most common cause of megaloblastic anemia is:
A. Lack of folic acid in diet
B. Inability to absorb vit B12
C. Iron deficiency in the diet
D. Chronic blood loss