Untitled Quiz

Density is the mass per unit volume of the material.

Upper dentures need to be made of materials with low density to prevent them from feeling heavy or uncomfortable in the mouth.

Molten alloys with low density require higher pressure during casting to fill the mold cavities effectively.

<p>Thermal conductivity is the ability of a material to transfer heat.</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>The coefficient of thermal conductivity (K) is the amount of heat transported per unit of time across a unit area. It's measured in Watts per meter per Kelvin (W/(m * K)).</p> Signup and view all the answers

<p>The coefficient of thermal expansion (α) is a measure of the change in length per unit length for a 1°C change in temperature. As temperature increases (or decreases), the interatomic distances within a material expand (contract), leading to overall dimensional changes.</p> Signup and view all the answers

<p>Close matching of the coefficient of thermal expansion between the tooth and restorative material is crucial to prevent marginal leakage or microleakage.</p> Signup and view all the answers

<p>The coefficient of thermal expansion needs to be closely matched between porcelain and metal in ceramo-metallic restorations to avoid issues with metal-ceramic bonding.</p> Signup and view all the answers

<p>The coefficient of thermal expansion should be closely matched between artificial teeth and the denture base to avoid crazing.</p> Signup and view all the answers

<p>The melting temperature of a material is the point at which it transitions from a solid state to a liquid state.</p> Signup and view all the answers

<p>The melting temperature of metals and alloys plays a critical role in the casting process, determining the selection of the melting machine and the type of investment material used.</p> Signup and view all the answers

<p>The heat of fusion is the amount of heat energy required to convert 1 gram of a substance from a solid state to a liquid state.</p> Signup and view all the answers

<p>Specific heat is the amount of heat energy in calories required to increase the temperature of 1 gram of a substance by 1°C.</p> Signup and view all the answers

<p>False</p> Signup and view all the answers

<p>Thermal diffusivity is the rate at which a material reaches thermal equilibrium, which is a uniform temperature throughout the material.</p> Signup and view all the answers

<p>Gold or amalgam restorations, due to their high thermal diffusivity, can cause sudden temperature changes called thermal shock.</p> Signup and view all the answers

<p>Optics is the science of studying light, sight (how well the eyes capture images), and vision (how the brain processes visual information), including color.</p> Signup and view all the answers

<p>Light is a stream of photons and its color is determined by its wavelength.</p> Signup and view all the answers

<p>Thermal</p> Signup and view all the answers

<p>Reflection</p> Signup and view all the answers

<p>Specular reflection occurs when light strikes a smooth surface, resulting in a reflected light beam that travels in a single direction, making the surface appear shiny.</p> Signup and view all the answers

<p>Diffuse reflection occurs when light strikes a rough surface, resulting in the reflected light being scattered in multiple directions, making the surface appear dull.</p> Signup and view all the answers

<p>A highly smooth and polished surface is necessary for specular reflection.</p> Signup and view all the answers

<p>Refraction is the bending of light as it passes from one medium to another with a different refractive index.</p> Signup and view all the answers

<p>Matching the refractive index of the dispersed phase and matrix phase helps to minimize the scattering of light, resulting in a more natural appearance of the restoration.</p> Signup and view all the answers

<p>Scattering occurs when light rays passing through a medium encounter inclusions or irregularities, causing the light to be redirected in various directions and reducing its intensity, or being attenuated.</p> Signup and view all the answers

<p>The presence of scattering centers makes light emerge in all directions. This can affect the overall translucency or opacity of the material.</p> Signup and view all the answers

<p>Transparency allows light to pass through a material without scattering or absorption. Translucency allows some light to pass through, but scatters or reflects some light back. Opacity prevents the transmission of light, absorbing it or reflecting it back.</p> Signup and view all the answers

<p>Luminescence is the emission of light by a substance that is not a result of heat. It can occur through fluorescence or phosphorescence.</p> Signup and view all the answers

<p>Fluorescence occurs when a substance absorbs light energy and then immediately emits light of a longer wavelength. Phosphorescence occurs when a substance absorbs light energy and then continues to emit light for a longer period even after the light source is removed.</p> Signup and view all the answers

<p>Sound human teeth emit fluorescent light when excited by ultraviolet radiation, contributing to their natural brightness and vitality.</p> Signup and view all the answers

<p>Restorative materials and dental porcelains are often formulated with fluorescing agents to mimic the natural fluorescence of teeth and improve their aesthetic appearance.</p> Signup and view all the answers

<p>LASER stands for Light Amplification by Stimulated Emission of Radiation.</p> Signup and view all the answers

<p>A specific medium, whether solid, liquid, or gas, is stimulated by high energy to produce a special type of light called laser.</p> Signup and view all the answers

<p>Monochromatic</p> Signup and view all the answers

<p>Lasers are typically named according to the medium used in their production; for example, CO2 laser, Argon laser, and Diode laser.</p> Signup and view all the answers

<p>Ulcer Healing</p> Signup and view all the answers

<p>Welding</p> Signup and view all the answers

<p>The three dimensions of color in the Munsell color system are hue, chroma, and value.</p> Signup and view all the answers

<p>Hue refers to the pure color of the object, often determined by the dominant wavelength of light reflected or transmitted by the object, for example, blue, green, or red.</p> Signup and view all the answers

<p>Chroma represents the saturation, intensity, or vividness of the hue. It indicates how much of the pure hue is present in the color.</p> Signup and view all the answers

<p>Value represents the lightness or darkness of a color, effectively indicating how much black or white is present in the color.</p> Signup and view all the answers

<p>A restoration with a value that is too high will appear too bright, making it look false and artificial.</p> Signup and view all the answers

<p>A restoration with a value that's too dark will appear dull and lifeless, lacking the natural brightness of the surrounding teeth.</p> Signup and view all the answers

<p>Metamerism refers to the phenomenon where two objects that appear to match in color under one light source might appear different under another light source.</p> Signup and view all the answers

<p>A metameric pair consists of two objects that appear to match in color under one light source but not under other light sources.</p> Signup and view all the answers

<p>An isomeric pair consists of two objects that appear to match in color under all light sources.</p> Signup and view all the answers

<p>Shade color matching is the process of determining the color of natural teeth to select an artificial material that possesses a similar color for restorations.</p> Signup and view all the answers

<p>Photocolorimetry</p> Signup and view all the answers