bonds
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Created by:
sandycheeks76 on September 10, 2011
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51 terms
Terms | Definitions |
|---|---|
 Why is it necessary to study the science of dental materials | Help us to explain The properties and performance of material, examine the internal structures of the dental materials, atomic makeup of matter allows us to predict the properties |
| States of matter | Solid, liquid,gas,colliod |
| Atomic bonds | Are cohesive forces, are the bindings forces that holds atoms together, are the results of electromagnetic forces |
| Solids | Are rigid and dence, have low vapor pressure, have low energy state, resist external forces, has the strongest atomic bond, is characterized by a space lattice |
| Space lattice | Most common form is a cubic, in the shape of all solids |
| interatomical distance | Atoms in a space lattice maintaining their position relative to 1 another |
| Normal interatomic distance | The distance at which the force of attraction between atoms equals the force needed to repel them |
| Cubic shape of space lattice can be either _____ _____ _____ or they can be in ____ range _____ | Short range order, long, order |
| 2 types of solids | Chrystalline and amorphous |
| Short range order | Consistent range only 5 to 10 neighbors apart |
| Long range order | 3 d spatial relationships of repeated atoms and molecules are millions of thousands of neighbors apart but the distance is consistent |
| Liquids | Have short range order, energy level is high, has a stronger attraction between molecules than gases but not as strong as solids, are unable to carry a load or maintain a shape without support |
| Molecular relationship of water | Molecules are 5 to 10 neighbors apart |
| Gases | Atomic bonds are week, has no molecular organization, and will take on any 3 d shape of any container, if thermal energy is removed by cooling it will condense into liquid, has no given volume, has highest energy level |
| Colloid | Is a mixture of gases, liquid, and solids |
| Types of bonds | Primary bonds, secondary bond |
| Primary bonds | Are strong bonds between atoms that involve the transfer or sharing of electrons between atoms |
| Valence electrons | Electrons involved in chemical reactions and atomic bonds |
| Ionic bond | Occurs when 1 atom donates its electrons to another, And both become stable through linkage |
| Ionic bond occurs when there is ___________ between a _______ and ________ charge | Interaction, positive, negative |
| Ionic bonds are not as strong as _________ _____ | Covalent bonds |
| Examples of ionic bonds | Sodium chloride, table salt, porcelain |
| Covalent bond | Are strong and stable, is the result of sharing of electrons between 2 atoms, is very directional |
| Crytallines | Has sharp and definite melting or freezing points, Are both long and short range order, Resist forces, Most used in dentistry are the cubic type space lattice |
| Examples of christallines | Salt, diamonds, hydroxyapatite of teeth, gold, silver alloy |
| Amorphous | Is without form, has no definite space lattice, has short range order, molecules tend to be distributed random, does not have a definite melting or freezing point, has closer 3 d relationship |
| Few materials are bonded only by ________ _____, usually a combination of ________ and _________ _____ | Covalent bonds, covalent and hydrogen bonds |
| Metallic bonds | Occurs when many atoms share all of their outer valence electronics with their neighbors, arrangement is very strong and stable, makeup is dense and heavy |
| Secondary bonds | Are partial charges the result from an uneven distribution of electrons around an atom or molecule, are weaker and less stable |
| Metallic bonds are ____ __________ of ____ and ___________ | Good conductors, Heat, electricity |
| _________ charges of secondary bonds can be _________ or _________, ____ or ______ | Partial, temporary, permanent, weak, strong |
| ________ _____ are responsible for the limited strength in polymers, and has ________ ________ _____ of ______ and individual ______ of ________ _____ | Secondary bonds, Internal covalent bonds, carbon, chains of hydrogen bonds |
| Hydrogen bonds | Are special type of permanent dipole, contains only 1 electron although weak, is the strongest all secondary bonds |
| Hydrogen bonds are important in ______ ________ and in ___ and ________ | Dental Polymers, dna, protein |
| Atomic bonds as they relate to dental materials | Metals, ceramics, polymers, composite |
| Why is colloid not a true solution? | Because 1 material will not disolve into another |
| Examples of colloid | Fluoride foam, alginate, reversible hydrocolloid |
| An _____ _________occurs between a _____ ________ and a cement and a _____ structure | Ionic interaction, glass ionomer, tooth |
| Examples of covalent bonds | Carbon-carbon bond that holds the polymer chain of dental composites and dentures, Protein, DNA |
| All metals in dentistry consist of _________ _____ | Metallic bonds |
| Metals are: | Opaque in nature, have luster, and electrical conductivity |
| Ceramics are: | Bonded with ionic bonds, are strong when compressed |
| Polymers | Consent of repeating units of long chains of covalent bonds, and weaker individual hydrogen bonds, has high molecular weight compound, are poor conductors of heat |
| Variety of bonds between the polymer chain that help to determine its strength | Cross linking, linear polymers, and permanent dipole |
| Polymers with permanent dipoles | Have a side group with an uneven distribution of elect,,ron |
| With permanent dipoles, as the ______ and intensity of the charges _________ so does the _______ and _________ | Number, increases, strength, stiffness |
| Example of polymer with permanent dipoles | PFI and yellow tip probe |
| Linear polymers | Contains a fluctuating dipoles, which is a weak bond that is broken easily as the chains slide by one another at room temperature, are processed by heat, has a secondary bond |
| Examples of linear polymer | Plastic bags, bleaching trays, bite guards |
| Cross linking polymers | Are linked by covalently bonded atoms, preventing them from sliding past on another |
| Cross-linking results in a _____ somewhat ________ _______ that can sometimes be ________, according to the amount of ____ _____ that exist | Stiff, stronger material, stretched, cross links |
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