Best investment for casting base metal crowns is:

 # Best investment for casting base metal crowns is:

A. Phosphate bonded investment

B. Gypsum  bonded investment

C. Ethyl silicate 

D. High grade silicate bonded

The correct answer is: A. Phosphate bonded investment.

Gypsum bonded investments are used for casting gold alloys. These can withstand a temperature of 700 degree C.

Base metal alloys, high melting gold alloys, which are used for metal ceramic restorations, are invested by phosphate bonded investments.

Silica bonded investments are an alternative to the phosphate bonded investments, for high temperature casting. They are used in the casting of base metal alloy partial dentures. 

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Stages of Anesthesia

 The different stages of anesthesia are:

Stage I: Analgesia and conscious sedation

Stage II: Stage of delirium

Stage III: Stage of Surgical Anesthesia

                Plane I: Pupils dilate progressively with the depth of anesthesia. Lid reflex, swallowing,                                            retching  and vomitting gets abolished. Corneal reflex is present. Conjunctival                                          reflex is absent. Pharyngeal reflex is lost.

                 Plane II: Eye balls fixed, laryngeal reflexes are also abolished.

                 Plane III: Asynchrony between thoracic and abdominal movements. Progressive paralysis of                                       intercostal muscles, Pupillary light reflex and corneal reflex are lost.

                 Plane IV: Complete intercostal muscle paralysis. Pupils are dilated. Muscles are flaccid.

Stage IV: Stage of respiratory paralysis

Minor surgeries like dental extractions are carried out in stage I or stage of analgesia. Major surgeries are carried out on Plane III of Stage III of General Anesthesia or the stage of Surgical Anesthesia. 

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True about herpetic gingivostomatitis

 # Which of the following is true about herpetic gingivostomatitis?

A. Common in children

B. Affects the gingiva uniformly

C. Occurs only in adults

D. It occurs on labile mucosa

The correct answer is: A. Common in children.

- Herpetic gingivostomatitis is common in  preschool children. 

- Initially focal areas of the marginal gingiva are red and swollen.

- Labile mucosa is commonly involved in recurrent aphthous ulcers.

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Color matching for composites

 # The color matching for composites when done in a dry state, would make the tooth appear:

A. Darker than the adjacent teeth

B. Lighter than the adjacent teeth

C. Same as that of the adjacent teeth

D. Does not have any effect

The correct answer is B. Lighter than the adjacent teeth.

Dehydrated or dry tooth appear whiter in shade.

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Removal of interproximal plaque

 # The method of choice for removal of interproximal plaque is:

A. Unitufted waxed floss

B. Multitufted unwaxed floss

C. Multitufted waxed floss

D. Unitufted unwaxed floss

The correct answer is C. Multitufted waxed floss.

For  areas of tight interproximal contacts, it is usually easier to use waxed than unwaxed floss.

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Buttressing bone formation is:

# Buttressing bone formation is:

A. Congenital abnormality

B. Occurs endosteally

C. Occurs periosteally

D. Due to trauma from occlusion

 

The correct answer is D. Due to trauma from occlusion. 

- When excessive occlusal forces resorb bone, the bone attempts to reinforced the thinned bony trabeculae with new bone. This attempt to compensate for lost bone is called buttressing bone formation - may be central or peripheral. Peripheral butteressing boine formation is also called lipping. 

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Treatment of odontogenic keratocyst extending into the mandibular ramus is:

 # Treatment of odontogenic keratocyst extending into the mandibular ramus is:

A. Enucleation without curettage

B. Marsupialization without curettage

C. Enucleation with peripheral osteotomy

D. Enbloc dissection

The correct answer is C. Enucleation with peripheral osteotomy.

Enucleation with curettage: Enucleation with curettage means that after enucleation, a curette or bur is used to remove 1 or 2 mm of bone around the entire periphery of the cystic cavity. This is done to remove any remaining epithelial cells that may be present in the periphery of the cystic wall or bony cavity.

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