Maxillary canine missing FPD

# In a case where maxillary canine is missing and we have to make a tooth-supported FPD, the abutment will be:
a) Central incisor, Lateral incisor and 1st premolar
b) Lateral incisor, 1st premolar 2nd premolar
c) Lateral incisor and 1st premolar
d) It depends upon periodontal status of remaining teeth

The correct answer is A. Central incisor, lateral incisor and first premolar.

Missing maxillary canine or mandibular canine (one tooth) come under complex fixed partial dentures and central incisor, lateral incisor and 1'1 premolar acts as abutments, whereas for other teeth(incisors, premolars and molars) the adjacent teeth in relation to the missing tooth are enough

to act as abutments.

FPD replacing canines can be difficult because the canine often lies outside the inner abutment axis.

An edentulous space created by the loss of a canine and any two contiguous teeth is best restored with a RPD.

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The posterior tooth that gives a better support is:

# The posterior tooth that gives a better support is:
a) With convergent roots
b) Divergent roots
c) Conical roots
d) Curved roots

The correct answer is B. Divergent roots.

- Roots with greater labiolingual width than mesiodistal width are preferable to roots that are round in cross section.

• Long, irregularly shaped and divergent roots offer great support.

• Short, conical and blunted roots offer poor support.

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Functional cusp Bevel

# The functional cusps are bevelled in the preparation of posterior cast crowns:
a) To reduce the stress at the line angles
b) To prevent the fracture of the tooth structure
c) For the structural durability of the restoration
d) To help in the retention

Bevelling of the functional cusp (lingual inclines of maxillary lingual cusps and the buccal inclines of mandibular buccal cusps) is an integral part in obtaining the structural durability of the restoration.

- Lack of functional cusp bevel can cause:

• A thin area or perforation on the casting.

• Overcontouring and poor occlusion of the restoration.

• Loss of tooth structure and retention.

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Forces acting through FPD on Abutment tooth

# The forces acting through a fixed partial denture on the
abutment tooth should be directed:
a) As far as possible at right angles to the long axis of the teeth
b) Parallel to the long axis of the teeth
c) By decreasing the mesio-distal dimension
d) None of the above

The correct answer is B. Parallel to the long axis of the teeth/

Ideally, the forces acting on the abutment tooth should be parallel to long axis of the tooth and should be within the confines of the root. By this, the stress is directed vertically which is well tolerated by the periodontium. Narrowing the buccolingual width of occlusal surfaces of the constructed crowns help to achieve these desirable forces.

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Ultrasonic instruments contraindications

# Ultrasonic instruments are indicated for each of the following types of patients EXCEPT one. Which is the EXCEPTION?
A. Active infectious disease
B. Deep periodontal pockets
C. Controlled diabetic
D. Edematous tissue
E.Mildly uncontrolled diabetic

Ultrasonic instruments should NOT be used
for patients with active infectious disease
because the aerosol created by the instruments serves to spread the infection
around the operatory.

Diabetes and deep periodontal pockets are
indications that ultrasonic instrumentation.

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Full thickness Flaps

# Each of the following is associated with
full-thickness flaps EXCEPT one. Which is the EXCEPTION?
A. Periosteum stays on the bone
B. Apical repositioning
C. Osseous recontouring
D. Dissection of the tissue with a blunt instrument

The correct answer is A. Periosteum stays on the bone. 

A full thickness flap includes stripping all of

the soft tissue (epithelium, connective

tissue, periostuem) from the bone.

Following placement of the incisions, the

flap is dissected using blunt instruments

like a # 9 molt to separate the soft tissue

from the bone.

Full thickness flaps are used when

recontouring the osseus structures below

or when the gingiva are repositioned

apically.

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Sharpening Dental Hand Instruments

# When sharpening instruments, the ______ of the blade should be placed at an angle ________ to the sharpening stone.
A. Bevel, 90
B. Bevel, 45
C. Working end, 45
D. Working end, 90°

The correct answer is B. Bevel, 45

When sharpening an instrument, the bevel
of the blade is placed at an angle of 45° to
the sharpening stone. This ensures
maximum efficiency of the blade to sharpen the instrument.

Instrument sharpening is an important
aspect of operative dentistry. Dull
instrument are not recommended for
carrying out procedures in the oral cavity.

Dull instruments are prone to produce more heat, are less efficient and can damage tooth structure. It is recommended to  discard those instruments which cannot be sharpened.

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