Operative Dentistry MCQ Answer 20

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The correct answer is e. (5 is a false statement).

1. Is a true statement.

2. Is true. Biocompatibility is measured on the basis of localized cytotoxicity (such as pulp and mucosal response), systemic responses, allergenicity, and carcinogenicity.

3. Is true. Methylated mercury accumulates in the food chain and is derived from areas of undersea volcanic acidity and hydrothermal waters. Virtually 100% of methyl mercury is absorbed in the gut. Thus, conversion of elemental mercury to methyl mercury would greatly increase absorption via the gastrointestinal route. All of the mercury in seafood is methyl mercury and all is absorbed. The average contribution of one seafood meal per week to blood mercury levels of methyl mercury is many times that of the aberage contribution of elemental mercury from the presence of 8-10 amalgam restorations in the mouth.

4. Is true. Ten percent of the female population if allergic to nickel, compared with only about 1% of the male population. This disparity is attributed to the greater exposure of females to nickel. Almost all gold plated jewelry is made with a nickel undercoat beneath the gold plating Only about 30% of those patients with a known nickel allergy develop a reaction to an intraoral nickel-chromium dental alloy.

5. Is false. Berylliosis is an inflammatory lung disease resulting from the inhalation of beryllium dust or fumes. Beryllium containing alloy should be ground with adequate ventilation.

References:

Anusavice K: Philips’ Science of Dental Materials, 10^th Ed. WB Saunders, 1996.