The Chemistry of Dental Materials
Dentists must use materials that are suitable for the undergoing actions within the mouth when performing any procedure. Dentists must also know what the tooth is composed as well as the properties of the materials in order to maximize the use of the materials to best fit the needs of the tooth.
In order to perform a filling or crown, dentists use what they have learnt from metallurgy (specifically, dental metallurgy), which is the science of producing and using metals.
Filling materials are used for restoring a defective tooth (cavities, fracture, etc.) to its original form and the protection of its sensitive tissues against further decay.
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The ideal filling material would posses the following properties:
Unfortunately no single material that a dentist posses (can use), hold all of these properties. Instead they choose one most suitable or combines the metal with alloys.
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The materials used in dentistry can be classified as follows:
1. Metallic materials (elements and compounds, in dentistry that undergo pressure):
(a) Noble (gases) metals and their alloys
(b) Base metals and their alloys
(c) Mercury and the amalgams
(d) Tool metals
2. Non-metallic inorganic materials:
Substances used in dentistry composition, ex. Polishing powders, e.g. pumice, chalk, putty powder, fluxes, alkali carbonates, anesthetic,
and nitrous oxide
3. Organic materials:
Of importance: Antiseptics, phenol
Impression substances, waxes, gums, resins
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The mouth is a moist environment, so dentists need to use insoluble fillings/compounds that will not disintegrate in the presence of saliva, water, food, etc.
Common Fillings - Advantages and Disadvantages:
Among all the filling materials, gold lies among them. Gold posses some of the positive properties of:
It also has disadvantages:
Amalgam fillings were popular in the 1800's until recently scientists became concerned with the amount of mercury in them. In which causing aesthetics, environmental, pollution, and health concerns, later leading the use of amalgam fillings diminished (except silver amalgam fillings), although they were affordable and contained properties desired by dentists (easy to work with).
Today, some of the most popular fillings include porcelain, silver amalgam, and composite resin fillings.
Silver amalgam must contain a minimum of the following according to the ADA (American Dental Association), replicating CDA (Canada Dental Association):
In order to perform a filling or crown, dentists use what they have learnt from metallurgy (specifically, dental metallurgy), which is the science of producing and using metals.
Filling materials are used for restoring a defective tooth (cavities, fracture, etc.) to its original form and the protection of its sensitive tissues against further decay.
______________________________________________________________________________________________________________
The ideal filling material would posses the following properties:
- Adhere firmly to cavity walls and once in position (cohesive), would not expand contract nor turn or twist out of shape
- Would not be affected by oral fluids and would not have harmful chemical actions on tissues in the mouth
- Would be a non-conductor of thermal changes within the mouth
- Match tooth colour and appearance (and be malleable and ductile which vary with temperatures (ex. annealing), the important application of the metals used in dental practice largely depends on these properties. This is important for the use of fillings as well as dental appliances, ex. Braces)
- Capable to maintain a high polish
- Would not form a crack where bacteria could live and reproduce, and food debris can linger
Unfortunately no single material that a dentist posses (can use), hold all of these properties. Instead they choose one most suitable or combines the metal with alloys.
______________________________________________________________________________________________________________
The materials used in dentistry can be classified as follows:
1. Metallic materials (elements and compounds, in dentistry that undergo pressure):
(a) Noble (gases) metals and their alloys
(b) Base metals and their alloys
(c) Mercury and the amalgams
(d) Tool metals
2. Non-metallic inorganic materials:
Substances used in dentistry composition, ex. Polishing powders, e.g. pumice, chalk, putty powder, fluxes, alkali carbonates, anesthetic,
and nitrous oxide
3. Organic materials:
Of importance: Antiseptics, phenol
Impression substances, waxes, gums, resins
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The mouth is a moist environment, so dentists need to use insoluble fillings/compounds that will not disintegrate in the presence of saliva, water, food, etc.
- Healthy dentin is moist, so a material needed is one which can bond to the tooth and not dissolve in the mouth (dental bond)
- There is a chemical bond between the tooth and filling material that must be unitized properly for maximum performance
Common Fillings - Advantages and Disadvantages:
Among all the filling materials, gold lies among them. Gold posses some of the positive properties of:
- Durability: Gold is a soft but strong metal, especially when combined with another non-toxic metal to increase its strength and colour match to the tooth. Over time, teeth begin to wear and tear from all the beating. Gold is capable of taking that beating because it is durable (doesn't corrode) and long-lasting (10-15 years). Some studies show that gold takes the same slow wearing (in certain cases) as human teeth. Thus making gold cost effective in the long term where as other filling materials have low durability.
- Stability: Gold is stable in that it works well with the natural functioning of the gums and mouth. For example, gold doesn't degrade opposing teeth or harm the surrounding area in any way.
- Preserves its form, colour and high polish
- Forms a perfectly water tight plug
- Chemically inert (under various normal mouth conditions)
It also has disadvantages:
- It can only be applied to a strong tooth (enamel must be strong enough to withstand the strain of condensing the filling)
- It must be kept dry during the filling
- The colour contrasts the natural colour of the tooth, but to make due with this colour change, other pure metals such as platinum and tin may be alloyed with the gold
Amalgam fillings were popular in the 1800's until recently scientists became concerned with the amount of mercury in them. In which causing aesthetics, environmental, pollution, and health concerns, later leading the use of amalgam fillings diminished (except silver amalgam fillings), although they were affordable and contained properties desired by dentists (easy to work with).
Today, some of the most popular fillings include porcelain, silver amalgam, and composite resin fillings.
Silver amalgam must contain a minimum of the following according to the ADA (American Dental Association), replicating CDA (Canada Dental Association):
- Silver, 65%
- Tin, 25%
- Copper, 6%
- Zinc, 2%
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Here are some other materials dentists use:
Zinc Phosphate Cement (zinc oxide and phosphoric acid) is used as a cementing agent for crowns and FPD's (fixed partial dentures). It produces heat when mixed, therefor a dentist must mix it over a large area to scatter the generated heat, as this heat will accelerate the setting time.
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Dental Fluoride is used when a patient isn't receiving enough fluoride in their diet. Thus they will usually have a mix of white and clear spots on their teeth. Dentists can prescribe tablets, making sure before they know of the patients medical conditions or what medication they are currently on. They can also fill trays with fluoride to give your mouth an extra boost. Fluoride is taken up by teeth and helps to strengthen them, resist acid, and block bacteria from forming cavities.
Fluoride works during the demineralization and remineralization processes that naturally occur in your mouth.
It can be found in fluoridated water, which was at one shown to lessen the amount of cavities but today those numbers have decreased. It is important for dentists to know this and why in order to create better ways in prevention of demineralization due to lack of fluoride.
Here are some other materials dentists use:
Zinc Phosphate Cement (zinc oxide and phosphoric acid) is used as a cementing agent for crowns and FPD's (fixed partial dentures). It produces heat when mixed, therefor a dentist must mix it over a large area to scatter the generated heat, as this heat will accelerate the setting time.
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Dental Fluoride is used when a patient isn't receiving enough fluoride in their diet. Thus they will usually have a mix of white and clear spots on their teeth. Dentists can prescribe tablets, making sure before they know of the patients medical conditions or what medication they are currently on. They can also fill trays with fluoride to give your mouth an extra boost. Fluoride is taken up by teeth and helps to strengthen them, resist acid, and block bacteria from forming cavities.
Fluoride works during the demineralization and remineralization processes that naturally occur in your mouth.
- Saliva works to neutralize the amount of acids in your mouth that cause demineralization of the calcium and phosphorous under the tooth's surface.
- When the saliva is less acidic it does just the opposite, replenishing the calcium and phosphorous that keep your teeth hard. This process is caused remineralization. When fluoride is present during remineralization, the minerals deposited are harder than they would otherwise be, helping to strengthen your teeth and prevent dissolution during the next demineralization phase
It can be found in fluoridated water, which was at one shown to lessen the amount of cavities but today those numbers have decreased. It is important for dentists to know this and why in order to create better ways in prevention of demineralization due to lack of fluoride.
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Other materials in dentistry like whitening - bicarbonate, and calcium hydroxide and their uses, properties, safety precautions, all relate to chemistry. Miss use of any of these materials can cause injury to the dentist or his patient. It is important for dentists to understand the chemical and physical properties of the materials they work with in order to insure this safety.
Other materials in dentistry like whitening - bicarbonate, and calcium hydroxide and their uses, properties, safety precautions, all relate to chemistry. Miss use of any of these materials can cause injury to the dentist or his patient. It is important for dentists to understand the chemical and physical properties of the materials they work with in order to insure this safety.