TEST BANK FOR DENTAL MATERIALS 3RDEDITION BY HATRICK

Chapter 02: Oral Environment and Patient Considerations MULTIPLE CHOICE 1. Some dental materials may be therapeutic in small quantities or if in contact with tissues for a short period of time. Dental materials may be irritating or toxic with longer or larger doses. a. Both statements are true. b. Both statements are false. c. The first statement is true, and the second statement is false. d. The first statement is false, and the second statement is true. ANS: A Some dental materials may be therapeutic in small quantities or if in contact with tissues for a short period of time but also may be irritating or toxic with longer or larger doses. Topical fluoride is of great benefit when used according to manufacturers’ directions but can be irritating to soft tissues and can even excessively etch enamel if used improperly. REF: p. 9 TOP: Biocompatibility 2. Normal masticatory forces on the occlusal surfaces of molar teeth can increase to as much as pounds per square inch on a cusp tip. a. 280 b. 1000 c. 10,000 d. 28,000 ANS: D Normal masticatory forces on the occlusal surfaces of molar teeth can increase to as much as 28,000 pounds per square inch on a cusp tip. Normal masticatory forces on the occlusal surfaces of molar teeth average 90 to 200 pounds. Masticatory forces decrease in incisor areas and can increase during bruxing or clenching. REF: p. 10 TOP: Force and Stress 3. force is applied when two surfaces slide against each other in opposite directions. a. Compressive b. Shearing c. Tensile d. Axial ANS: B Shearing force is applied when two surfaces slide against each other or in a twisting or rotating motion. An incisor used for cutting is an example of shearing forces. REF: p. 10 TOP: Force and Stress 4. Stress is the amount of force exerted from within an object, and is the amount of change that the force has produced. a. strain b. tension