SEARCH:

Metal that expands on solidification from the molten state is:

 # A metal that expands on solidification from the molten state is:
A. Gold
B. Silver
C. Bismuth
D. Copper



The correct answer is C. Bismuth.

Elemental bismuth is denser in the liquid phase than the solid, a characteristic it shares with germanium, silicon, gallium, and water. Bismuth expands 3.32% on solidification; therefore, it was long a component of low-melting typesetting alloys, where it compensated for the contraction of the other alloying components to form almost isostatic bismuth-lead eutectic alloys.

Self Appendectomy Performed by a Soviet General Practitioner

 A Soviet General Practitioner, Leonid Ivanovich Rogozov, had developed appendicitis while at Novolazarevskaya Station in April 1961, and being the only medical professional there at the time, had to perform his own appendectomy. 

Leonid Ivanovich Rogozov performing self Appendectomy



On the morning of 29 April 1961, Rogozov experienced general weakness, nausea, and moderate fever, and later pain in the lower right portion of his abdomen. None of the possible conservative treatments helped. By 30 April signs of localised peritonitis became apparent, and his condition worsened considerably by the evening. Mirny, the nearest Soviet research station, was more than 1,000 miles from Novolazarevskaya. Antarctic research stations of other countries did not have an aircraft available. Severe blizzard conditions prevented aircraft landing in any case. Rogozov had no option but to perform an operation on himself.

The operation started at 02:00 local time on 1 May with the help of a driver and meteorologist, who provided instruments and held a mirror so Rogozov could observe areas not directly visible. Rogozov lay in a semi-reclining position, half-turned to his left side. A solution of 0.5% novocaine was used for local anesthesia of the abdominal wall. Rogozov made a 10–12 cm incision of the abdominal wall, but while opening the peritoneum he accidentally cut the cecum and had to suture it. Then he exposed the appendix. According to his report, the appendix was found to have a dark stain at its base, and Rogozov estimated it would have burst within a day. The appendix was resected and antibiotics were applied directly into the peritoneal cavity. General weakness and nausea developed about 30–40 minutes after the start of the operation so that short pauses for rest were repeatedly needed after that. By about 04:00 the operation was complete.

After the operation gradual improvement occurred in the signs of peritonitis and in the general condition of Rogozov. Body temperature returned to normal after five days, and the stitches were removed seven days after the operation. He resumed his regular duties in about two weeks.

The self-surgery, which was photographed by his colleagues, captured the imagination of the Soviet public at the time. In 1961 he was awarded the Order of the Red Banner of Labour. The incident resulted in a change of policy, and thereafter, extensive health checks were mandatory for personnel to be deployed on such expeditions.

Rogozov died in 2000, aged 66, in Saint Petersburg, Russia, from lung cancer.


The upper denture falls when the patient opens his mouth wide. This is due to:

  # The upper denture falls when the patient opens his mouth wide. This is due to:
A. Thick labial flange
B. Over extended borders
C. Thick distobuccal flange
D. Poor peripheral seal



The correct answer is C. Thick distobuccal flange

The thickness of distobuccal flange of maxillary denture must be adjusted to accommodate the ramus, coronoid process and the masseter. If the flange is too thick, the coronoid process will push the denture out of place during opening or lateral movements of mandible.

Posterior palatal seal is recorded when the head is bent at:

  # Posterior palatal seal is recorded when the head is bent at:
A. 15 degree
B. 30 degree
C. 45 degree
D. 60 degree



The correct answer is B. 30 degree.

In conventional method of recording posterior palatal seal, the patient is seated in an upright position. In fluid wax technique, posterior palatal seal is recorded when the head is bent at 30 degree.

The type of patient demanding to be educated before the complete denture fabrication:

 # The type of patient demanding to be educated before the complete denture fabrication:
A. Philosophical
B. Exacting
C. Indifferent
D. Hysterical



The correct answer is B. Exacting.

Exacting patients are precise in everything they do. They are immaculate in dress and appearance. Their
nature is to be satisfied only by perfection. They may demand that the dentist explain every step of the
treatment in detail. These patients should not be promised that they will be able to wear a prosthesis
without any inconvenience, because they will expect the dentist to live up to such promises. Potential
problems and inconveniences should be explained in detail before treatment is initiated.

The primary function of posterior palatal seal is to:

 # The primary function of posterior palatal seal is to:
A. Retention of upper denture by making a complete seal
B. Aid in insertion and removal of the upper denture
C. Achieve balanced occlusion
D. Retention of lower denture



The correct answer is A. Retention of upper denture by making a complete seal.

The primary purpose of PPS is the retention of the maxillary denture. PPS creates a partial vacuum beneath the maxillary denture. This partial vacuum is activated only when horizontal or tipping forces are directed against the denture base. The duration of this vacuum is small and so little or no irreversible alterations to the underlying mucosa will take place.


Face bow is used to record:

 # Face bow is used to record:
A. Orientation relation
B. Centric relation
C. Eccentric relation
D. Vertical jaw relation


The correct answer is A. Orientation relation.

The maxillary cast is attached to the articulator using the orientation jaw relation records. The procedure of transferring the orientation relation to the articulator is called face-bow transfer.

Orientation jaw relation is defined as: “the jaw relation when the mandible is kept in its most posterior position, it can rotate in the sagittal plane around an imaginary transverse axis passing through or near the condyles”—GPT.