Bisecting angle technique

# Bisecting angle technique is based on:
A. ALARA principle
B. SLOB Technique
C. Rule of Isometry
D. Convergence

The correct answer is C. Rule of Isometry.

The Bisecting angle technique is based on a simple geometric theorem, Cieszynski's rule of Isometry, which states that two triangles are equal when they share one complete side and have two equal angle.

Position of the film as close as possible to the lingual surface of the teeth, resting in the palate or on the floor of the mouth.

The plane of the film and the long axis of the teeth form an angle with its apex at the point where the film is in contact with the teeth.

Construct an imaginary line that bisects this angle and direct the central ray of the beam at right angles to this bisector.

This forms two triangles with two equal angles and  a common side. (the imaginary bisector)

Several methods can be used to support films intra orally for Bisecting angle projections.

The preferred method is to use a film holding instrument (e.g. The Snap-A-Ray) or Bisecting angle instrument. Both provide an external device for localizing the X ray beam.

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Pathognomic sign of mandibular fracture

# The most common pathognomic sign of mandibular fracture is:
a) Malocclusion
b) Sublingual hematoma
c) Deviation of the jaw on opening
d) Paraesthesia of the mental nerve

The correct answer is B. Sublingual hematoma.

Sublingual ecchymosis is considered as pathognomonic sign of mandibular fracture.

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Fracture of Mandible treatment

# The ideal treatment for fracture of the angle of mandible is:
a) Transosseous wiring
b) Intermaxillary fixation
c) Plating on the lateral side of the body of the mandible
d) Plating at the inferior border of the mandible

The correct answer is D. Plating at the inferior border of the mandible.

Compression plates are used at inferior border of mandible below the inferior dental canal. If there is opening of the upper border, it is necessary to apply a tension band in the form of arch bar or miniplates at the upper border.


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Gowgates technique Landmarks

# Extra-oral landmark for Gowgates technique of mandibular nerve block:
a) Corner of the mouth
b) Intertragic notch
c) Both of the above
d) None of the above

The correct answer is C. Both of the above

Landmarks for Gow-Gates technique:
a. Extraoral:
• Lower border of tragus (intertragic notch); • Corner of mouth
• Mesiolingual cusp of maxillary 2nd molar

 b. Intraoral:
• Height of injection established by placement of the needle tip just below the mesiolingual (mesiopalatal) cusp of maxillary second molar.
• Penetration of soft tissues just distal to the maxillary second molar at the highest established in the preceding step.

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Long duration of anesthesia

# Long duration anesthesia is achieved by:
a) 2% Lidocaine HCL +Epinephrine 1:200000
b) 3% Mepivacaine HCL
c) 4% Prilocaine HCL +Epinephrine 1:200000
d) 0.5% Bupivacaine+ Epinephrine 1:200000

The correct answer is D. 0.5% Bupivacaine+ Epinephrine 1:200000

Short Duration (pulpal anesthesia approximately 30 Minutes)
• Mepivacaine HCl 3%
- Prilocaine HCl 4% (by infiltration)

Intermediate Duration (Pulpal anesthesia approximately 60 Minutes) 
• Articaine HCL 4% + epinephrine 1:100,000 • Articaine HCl 4% +epinephrine 1:200,000
• Lidocaine HCl 2% +epinephrine 1:50,000
• Lidocaine HCl 2% +epinephrine 1:100,000
• Mepivacaine HCl 2% + levonordefrin 1:20,000
• Prilocaine HCl 4% (via nerve block only)
• Prilocaine HCl 4% +epinephrine 1:200,000

 Long Duration (Pulpal anesthesia approximately 90+ Minutes) 
• Bupivacaine HCl 0.5% + epinephrine 1:200,000 (by nerve block)

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Muscle pierced while giving IANB

#Which of the following muscles is pierced by the needle while giving an inferior alveolar nerve block?
a) Medial pterygoid
b) Temporalis
c) Superior constrictor
d) Buccinator

The correct answer is D. Buccinator.

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Non rigid Connectors, Fixed Partial Dentures

# The non-rigid connectors are used in the construction of FPD when the span is:
a) Short, supplementing alveolar ridge reduction
b) Short supplementing alveolar ridge reduction not required
c) Long, supplementing alveolar ridge reduction
d) Long, supplementing alveolar ridge reduction not required

• The correct answer is B. Short supplementing alveolar ridge reduction not required

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