1.
Elasticity is an example of which of the following properties?
Correct Answer
B. Mechanical
Explanation
Elasticity is a property that is commonly associated with mechanical systems. It refers to the ability of a material or object to deform under stress and then return to its original shape once the stress is removed. This property is often observed in materials such as rubber bands or springs, where they can be stretched or compressed and then regain their original form. Therefore, elasticity is an example of a mechanical property.
2.
An example of a physical property is:
Correct Answer
A. Density
Explanation
Density is a physical property because it is a characteristic that can be observed and measured without changing the substance's chemical composition. It is defined as the mass of a substance per unit volume. Density can be determined by dividing the mass of an object by its volume. Since density is a measurable quantity that describes how closely packed the particles of a substance are, it is considered a physical property.
3.
The ability of a material to dissolve in liquid is termed:
Correct Answer
C. Solubility
Explanation
Solubility refers to the ability of a material to dissolve in a liquid. It is a measure of how well a substance can mix with a solvent to form a homogeneous solution. The solubility of a substance depends on factors such as temperature, pressure, and the nature of the solvent and solute. When a material has high solubility, it readily dissolves in a liquid, whereas low solubility indicates that the material does not dissolve easily.
4.
The ability of an alloy to withstand mechanical stresses without permanent deformation is reflected by its__________________?
Correct Answer
D. Elasticity
Explanation
The ability of an alloy to withstand mechanical stresses without permanent deformation is reflected by its elasticity. Elasticity refers to the ability of a material to return to its original shape and size after the applied stress is removed. A highly elastic alloy can absorb and release energy without undergoing permanent deformation, making it resilient and able to withstand mechanical stresses.
5.
Property of the material, which describes the resistance to abrasion, is_________________?
Correct Answer
A. Hardness
Explanation
Hardness is the property of a material that describes its resistance to abrasion. It refers to the ability of a material to withstand scratching, indentation, or wear caused by friction. A material with high hardness will be more resistant to abrasion, while a material with low hardness will be more prone to wearing down or being scratched. Therefore, hardness is the correct answer as it directly relates to the resistance to abrasion.
6.
Stress in defined as_______________?
Correct Answer
D. An internal force opposing an applied load
Explanation
Stress is defined as an internal force opposing an applied load. When an external force is applied to an object, it creates a deformation in the object. This deformation creates internal forces within the object that resist the applied load. These internal forces are known as stress. Therefore, stress can be understood as the internal force that opposes the applied load and prevents further deformation.
7.
Hardness number measured by_____________?
Correct Answer
D. KNH
8.
Strain is defined as:
Correct Answer
B. A deformation resulting from an applied load
Explanation
Strain is defined as a deformation resulting from an applied load. When an external force is applied to a material, it causes the material to deform or change its shape. This change in shape is known as strain. It is a measure of how much the material has been stretched or compressed due to the applied load. Therefore, the correct answer is "A deformation resulting from an applied load."
9.
The KHN of enamel is:
Correct Answer
B. 350
Explanation
The KHN (Knoop Hardness Number) of enamel is 350. KHN is a measure of the hardness or resistance to indentation of a material. Enamel is the outermost layer of the tooth and is known for its high hardness. A KHN of 350 indicates that enamel is very hard and can withstand a significant amount of force without being easily indented or damaged.
10.
Goal of dentistry:
Correct Answer
D. All of the above
Explanation
The goal of dentistry includes preventing disease, relieving pain, and improving mastication efficiency. This means that dentistry aims to promote oral health by preventing dental diseases such as cavities and gum disease, providing treatment to alleviate any pain or discomfort experienced by patients, and enhancing the ability to chew and eat properly. Therefore, the correct answer is "All of the above" as all three options are valid objectives of dentistry.
11.
___________ is the force per unit area induced in the material in response to externally applied force, one part of the force is in one direction while the other is in the opposite direction.
Correct Answer
A. Shear stress
Explanation
Shear stress is the force per unit area induced in the material in response to externally applied force. Unlike tensile stress and compressive stress, shear stress occurs when the applied force is parallel to the surface of the material, causing one part of the force to be in one direction while the other part is in the opposite direction.
12.
There is a lot of materials have ideal physical and mechanical properties.
Correct Answer
B. False
Explanation
The statement is grammatically incorrect and should be corrected to "There are a lot of materials that have ideal physical and mechanical properties." This means that there are many materials that possess the desired physical and mechanical characteristics. However, the given answer is "False," indicating that the statement is incorrect.
13.
Dental materials play an integral role in dentistry.
Correct Answer
A. True
Explanation
Dental materials are essential in dentistry as they are used for various purposes such as filling cavities, repairing damaged teeth, creating dental prostheses, and improving the aesthetics of the teeth. These materials are designed to be biocompatible, durable, and esthetically pleasing to ensure the best outcomes for patients. Without dental materials, dentistry would not be able to provide the necessary treatments and procedures to maintain oral health and restore the function and appearance of teeth.
14.
- Every ________ is accompanied by a strain of the same type
Correct Answer
C. Stress
Explanation
Stress is a measure of the internal force experienced by a material when subjected to an external load. When a material is under stress, it will also experience a strain, which is the deformation or change in shape that occurs in response to the stress. Therefore, every stress is accompanied by a strain of the same type.
15.
- ___________include materials used to repair or replace tooth structure
Correct Answer
B. Restorative Materials
Explanation
Restorative materials are used to repair or replace tooth structure. These materials include dental fillings, dental crowns, dental bridges, and dental implants. They are used to restore the function and aesthetics of damaged or missing teeth. Restorative materials can be made from various materials such as amalgam, composite resin, porcelain, and metal alloys. These materials are chosen based on factors such as durability, esthetics, and the specific needs of the patient.
16.
Materials that are tooth-colored are often called esthetic materials
Correct Answer
A. True
Explanation
Tooth-colored materials are often referred to as esthetic materials because they closely resemble the natural color of teeth. These materials are commonly used in dental procedures such as fillings, crowns, and veneers to create a more natural and pleasing appearance. By using esthetic materials, dentists can match the color of the patient's teeth, resulting in a more seamless and aesthetically pleasing result. Therefore, the statement that tooth-colored materials are often called esthetic materials is true.
17.
- In the _________ type of corrosion, the metal reacts to form oxides and sulfides in the absence of electrolytes
Correct Answer
A. Chemical or dry corrosion
Explanation
Chemical or dry corrosion refers to the type of corrosion where the metal reacts with its environment to form oxides and sulfides in the absence of electrolytes. Unlike other types of corrosion, such as electrolytic or electrochemical corrosion, chemical or dry corrosion does not require the presence of an electrolyte solution for the reaction to occur. Instead, it occurs when the metal is exposed to gases or chemicals in the environment, leading to the formation of oxides and sulfides on the metal surface.
18.
Tarnish generally occurs in the oral cavity due to:
Correct Answer
D. All of the above
Explanation
Tarnish in the oral cavity can occur due to multiple factors. Hard and soft deposits such as calculus, mucin, and plaque can accumulate on the surface of the restoration, leading to tarnish. Additionally, pigment-producing bacteria can produce stains that contribute to tarnish. Furthermore, thin films of oxides, sulfides, or chlorides can form, causing tarnish. Therefore, all of the mentioned factors can contribute to tarnish in the oral cavity.
19.
- A systemic effect is a result of the direct contact of the material to the regions immediately adjacent to the material.
Correct Answer
B. False
Explanation
A systemic effect is not a result of direct contact with adjacent regions, but rather is a result of the material affecting the entire system or body. It can be caused by the material being absorbed into the bloodstream or affecting organs and tissues throughout the body. Therefore, the statement is false.
20.
- The __________ properties dependent on the amount of material & on the size & shape of the object.
Correct Answer
C. Mechanical
Explanation
Mechanical properties are dependent on the amount of material and on the size and shape of the object. These properties include strength, hardness, elasticity, and toughness, which determine how a material will behave under applied forces or loads. The amount of material affects these properties as more material means more resistance to deformation or failure. The size and shape of the object also play a role as they can affect the distribution of stresses and strains within the material. Therefore, mechanical properties are influenced by both the quantity of material and the geometric characteristics of the object.