Dental fillings
Encyclopedia
This page is about types of dental restorative materials. For dental fillings see dental restorations
Dental restorative materials are specially fabricated materials, designed for use as dental restorations (fillings), which are used to restore tooth
structure loss, usually resulting from but not limited to dental caries
(dental cavities). There are many challenges for the physical properties of the ideal dental restorative material.
, aesthetics
and application.
to manipulate.
is a metallic filling material composed from a mixture of mercury
(from 43% to 54%) and powdered alloy
made mostly of silver
, tin
, zinc
and copper
commonly called the amalgam alloy. Amalgam does not adhere to tooth structure without the aid of cements, or techniques which lock in the filling, using the same principles as a dovetail joint
. Amalgam is still used extensively in many parts of the world because of its cost effectiveness, superior strength and longevity. However their metallic colour is not aesthetic and tooth coloured alternatives are continually emerging with increasingly comparable properties. Due to the known toxicity
of the element mercury
, there is some controversy about the use of amalgams. *Amalgam: The most popular amalgam was a mixture of silver, tin and mercury. According to the authors of the article " It set very hard and lasted for many years, the major contradiction being that it oxidized in the mouth, turning teeth black. Also the mercury contained in the amalgam was thought at that time to be harmful." as explained in the pre-eminent dental textbook of that century, The Principles and Practice of Dental Surgery by Chapin A. Harris
A.M.
, M.D.
, D.D.S.. More recent dental texts strongly support the use of amalgam; "In summary, dental amalgam is a highly successful material clinically and is very cost effective, but alternatives such as cast gold and esthetic restorative materials are now very competitive in terms of frequency of use. Many argue, however, that the use of amalgam must be strongly supported given its large public health benefit in the United States and many other countries."
and plastic
resin, and can be made to resemble the appearance of the natural tooth. They are cosmetically superior to amalgam fillings. Composite resin fillings are usually more expensive than amalgam fillings. Bis-GMA based materials contain Bisphenol A
, a known endocrine disrupter chemical, and may contribute to the development of breast cancer
. PEX-based materials do not.
Most modern composite resins are light-cured photopolymer
s, meaning that they harden with light exposure. They can then be polished to achieve maximum aesthetic results. Composite resins experience a very small amount of shrinkage upon curing, causing the material to pull away from the walls of the cavity preparation. This makes the tooth slightly more vulnerable to microleakage and recurrent decay
. There are handling techniques combined with material selection,which minimize or eliminate microleakage.
In some circumstances, less tooth structure can be removed compared to preparation for other dental materials such as amalgam and many of the indirect methods of restoration
. This is because composite resins bind to enamel
(and dentin
too, although not as well) via a micromechanical bond. As conservation of tooth structure is a key ingredient in tooth preservation, many dentists prefer placing materials like composite instead of amalgam fillings whenever possible.
Generally, composite fillings are used to fill a carious lesion involving highly visible areas (such as the central incisors or any other teeth that can be seen when smiling) or when conservation of tooth structure is a top priority.
The bond of composite resin to tooth, is especially affected by moisture contamination and cleanliness of the prepared surface. Other materials can be selected when restoring teeth where moisture control techniques are not effective.
and an organic acid. Although they are tooth-colored, glass ionomers vary in translucency. Although glass ionomers can be used to achieve an aesthetic result, their aesthetic potential does not measure up to that provided by composite resins.
The cavity preparation of a glass ionomer filling is the same as a composite resin; it is considered a fairly conservative procedure as the bare minimum of tooth structure should be removed.
Conventional glass ionomers are chemically set via an acid-base reaction. Upon mixing of the material components, there is no light cure needed to harden the material once placed in the cavity preparation. After the initial set, glass ionomers still need time to fully set and harden.
Glass ionomers do have their advantages over composite resins:
1. They are not subject to shrinkage and microleakage, as the bonding mechanism is an acid-base reaction and not a polymerization reaction.
2. Glass ionomers contain and release fluoride
, which is important to preventing carious lesions. Furthermore, as glass ionomers release their fluoride, they can be "recharged" by the use of fluoride-containing toothpaste. Hence, they can be used as a treatment modality for patients who are at high risk for caries. Newer formulations of glass ionomers that contain light-cured resins can achieve a greater aesthetic result, but do not release fluoride as well as conventional glass ionomers.
Glass ionomers are about as expensive as composite resin. The fillings do not wear as well as composite resin fillings. Still, they are generally considered good materials to use for root caries and for sealants.
, an organic acid, and resin polymer
that harden when light cured. (The light activates a catalyst in the cement that causes it to cure in seconds.) The cost is similar to composite resin. It holds up better than glass ionomer, but not as well as composite resin, and is not recommended for biting surfaces of adult teeth.
In general, resin modified glass-ionomer cements can achieve a better aesthetic result than conventional glass ionomers, but not as good as pure composites. It has its own setting reaction.
fillings are hard, but can cause wear on opposing teeth. They are brittle and are not always recommended for molar
fillings.
was understood.
According to American Civil War
-era dental handbooks from the mid-19th century, since the early 19th century metallic fillings had been used, made of lead
, gold
, tin
, platinum
, silver
, aluminum, or amalgam
. A pellet was rolled slightly larger than the cavity, condensed into place with instruments, then shaped and polished in the patient's mouth. The filling was usually left "high", with final condensation — "tamping down" — occurring while the patient chewed food. Gold foil was the most popular and preferred filling material during the Civil War. Tin and amalgam were also popular due to lower cost, but were held in lower regard.
One survey of dental practices in the mid-19th century catalogued dental fillings found in the remains of seven Confederate soldiers from the U.S. Civil War; they were made of:
One advantage of gold restorations is longevity, because gold can outlast other materials by three to five times longer. When describing other materials, dentists talk in terms of years of service, whereas with cast gold, dentists speak of decades of service. To achieve the greatest longevity, gold dental work must be done with sufficient skill and precision, so discerning patients should seek gold dentists with quality training, experience and expertise.
Fillings fail because of changes in the filling, tooth or the bond between them.
Amalgam fillings expand with age, possibly cracking the tooth and requiring repair and filling replacement. Composite fillings shrink with age and may pull away from the tooth allowing leakage. Quality dental gold is the most biocompatible material used in dentistry today, being non-corrosive and hypo-allergenic. Dental gold’s wear rates and coefficient of thermal expansion is very similar to tooth enamel, which minimizes gaps, leakage or repair due to expansion differentials over time.
As chewing applies considerable pressure on the tooth, the filling may crack, allowing seepage and eventual decay in the tooth underneath. Gold margins do not break or chip even when thinned and polished, and can maintain microscopic gaps even smaller than the diameter of bacterium that cause tooth decay.
The tooth itself may be weakened by the filling and crack under the pressure of chewing. That will require further repairs to the tooth and replacement of the filling. On the other hand, less tooth structure is removed when preparing teeth for gold dental restoration, which leaves the tooth stronger and healthier.
Gold restorations, if done properly, could last the lifetime of a patient. As life expectancies increase, thoughtful dental material choices become even more important to reduce the number of times that fillings and other restorations must be replaced. Repeated repairs to teeth can lead to pulpal inflammation and necrosis, root canal therapy and the eventual necessity for crowns in lieu of fillings. Restoring a tooth only once, with highly durable, non-toxic, biocompatible materials like gold, can be very appealing to discerning patients, and be less costly and painful in the long run.
If fillings leak or if the original bond is inadequate, the bond may fail even if the filling and tooth are otherwise unchanged.
(NIOM) evaluates dental materials in the Nordic countries
. This research and testing institution are accredited to perform several test procedures for dental products. In Europe, dental materials are classified as medical devices according to the Medical Devices Directive
. In USA, the U.S. Food and Drug Administration is the regulatory body for dental products.
Dental restorative materials are specially fabricated materials, designed for use as dental restorations (fillings), which are used to restore tooth
Tooth
Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...
structure loss, usually resulting from but not limited to dental caries
Dental caries
Dental caries, also known as tooth decay or a cavity, is an irreversible infection usually bacterial in origin that causes demineralization of the hard tissues and destruction of the organic matter of the tooth, usually by production of acid by hydrolysis of the food debris accumulated on the...
(dental cavities). There are many challenges for the physical properties of the ideal dental restorative material.
Restorative material development
The goal of research and development is to develop the ideal restorative material. The ideal restorative material would be identical to natural tooth structure, in strength adherence and appearance. The properties of an ideal filling material can be divided into four categories: physical properties, biocompatibilityBiocompatibility
Biocompatibility is related to the behavior of biomaterials in various contexts. The term may refer to specific properties of a material without specifying where or how the material is used , or to more empirical clinical success of a whole device in...
, aesthetics
Aesthetics
Aesthetics is a branch of philosophy dealing with the nature of beauty, art, and taste, and with the creation and appreciation of beauty. It is more scientifically defined as the study of sensory or sensori-emotional values, sometimes called judgments of sentiment and taste...
and application.
Physical properties
Requisite physical properties include low thermal conductivity and expansion, resistance to different categories of forces and wear like attrition and abrasion and resistance to chemical erosion. There must also be good bonding strength to the tooth. Everyday masticatory forces and conditions must be withstood without fatiguing.Biocompatibility
Biocompatibility refers to how well the material coexists with the biological equilibrium of the tooth and body systems. Since fillings are in close contact with mucosa, tooth, and pulp, biocompatibility is very important. Common problems with some of the current dental materials include chemical leakage from the material, pulpal irritation and less commonly allergy. Some of the byproducts of the chemical reactions during different stages of material hardening need to be considered.Aesthetics
Filling materials ideally would match the surrounding tooth structure in shade, translucency, and texture.Application
Dental operators require materials that are easy to manipulate and shape, where the chemistry of any reactions that need to occur are predictable or controllable.Direct restorative materials
The chemistry of the setting reaction for direct restorative materials is designed to be more biologically compatible. Heat and byproducts generated cannot damage the tooth or patient, since the reaction needs to take place while in contact with the tooth during restoration. This ultimately limits the strength of the materials, since harder materials need more energyEnergy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
to manipulate.
Amalgam
AmalgamAmalgam (dentistry)
Amalgam is an alloy containing mercury. The term is commonly used for the amalgam employed as material for dental fillings, which consists of mercury , silver , tin , copper , and other trace metals...
is a metallic filling material composed from a mixture of mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
(from 43% to 54%) and powdered alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
made mostly of silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, tin
Tin
Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...
, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
and copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
commonly called the amalgam alloy. Amalgam does not adhere to tooth structure without the aid of cements, or techniques which lock in the filling, using the same principles as a dovetail joint
Dovetail joint
A dovetail joint or simply dovetail is a joint technique most commonly used in woodworking joinery. Noted for its resistance to being pulled apart , the dovetail joint is commonly used to join the sides of a drawer to the front....
. Amalgam is still used extensively in many parts of the world because of its cost effectiveness, superior strength and longevity. However their metallic colour is not aesthetic and tooth coloured alternatives are continually emerging with increasingly comparable properties. Due to the known toxicity
Toxicity
Toxicity is the degree to which a substance can damage a living or non-living organisms. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell or an organ , such as the liver...
of the element mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, there is some controversy about the use of amalgams. *Amalgam: The most popular amalgam was a mixture of silver, tin and mercury. According to the authors of the article " It set very hard and lasted for many years, the major contradiction being that it oxidized in the mouth, turning teeth black. Also the mercury contained in the amalgam was thought at that time to be harmful." as explained in the pre-eminent dental textbook of that century, The Principles and Practice of Dental Surgery by Chapin A. Harris
Chapin A. Harris
Chapin Aaron Harris A.M., M.D., D.D.S. was an American physician and dentist and dentistry school founder.-Education:...
A.M.
Master of Arts (postgraduate)
A Master of Arts from the Latin Magister Artium, is a type of Master's degree awarded by universities in many countries. The M.A. is usually contrasted with the M.S. or M.Sc. degrees...
, M.D.
Doctor of Medicine
Doctor of Medicine is a doctoral degree for physicians. The degree is granted by medical schools...
, D.D.S.. More recent dental texts strongly support the use of amalgam; "In summary, dental amalgam is a highly successful material clinically and is very cost effective, but alternatives such as cast gold and esthetic restorative materials are now very competitive in terms of frequency of use. Many argue, however, that the use of amalgam must be strongly supported given its large public health benefit in the United States and many other countries."
Composite resin
Composite resin fillings (also called white fillings) are a mixture of powdered glassGlass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
and plastic
Plastic
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce production costs...
resin, and can be made to resemble the appearance of the natural tooth. They are cosmetically superior to amalgam fillings. Composite resin fillings are usually more expensive than amalgam fillings. Bis-GMA based materials contain Bisphenol A
Bisphenol A
Bisphenol A is an organic compound with two phenol functional groups. It is used to make polycarbonate plastic and epoxy resins, along with other applications....
, a known endocrine disrupter chemical, and may contribute to the development of breast cancer
Breast cancer
Breast cancer is cancer originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. Cancers originating from ducts are known as ductal carcinomas; those originating from lobules are known as lobular carcinomas...
. PEX-based materials do not.
Most modern composite resins are light-cured photopolymer
Photopolymer
A photopolymer is a polymer that changes its properties when exposed to light, often in the ultraviolet spectrum. These polymers are useful in dentistry for fillings and in rapid prototyping in the stereolithography and 3D printing processes. This material is also used in the creation of ADA...
s, meaning that they harden with light exposure. They can then be polished to achieve maximum aesthetic results. Composite resins experience a very small amount of shrinkage upon curing, causing the material to pull away from the walls of the cavity preparation. This makes the tooth slightly more vulnerable to microleakage and recurrent decay
Dental caries
Dental caries, also known as tooth decay or a cavity, is an irreversible infection usually bacterial in origin that causes demineralization of the hard tissues and destruction of the organic matter of the tooth, usually by production of acid by hydrolysis of the food debris accumulated on the...
. There are handling techniques combined with material selection,which minimize or eliminate microleakage.
In some circumstances, less tooth structure can be removed compared to preparation for other dental materials such as amalgam and many of the indirect methods of restoration
Dental restoration
A dental restoration or dental filling is a dental restorative material used to restore the function, integrity and morphology of missing tooth structure. The structural loss typically results from caries or external trauma. It is also lost intentionally during tooth preparation to improve the...
. This is because composite resins bind to enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...
(and dentin
Dentin
Dentine is a calcified tissue of the body, and along with enamel, cementum, and pulp is one of the four major components of teeth. Usually, it is covered by enamel on the crown and cementum on the root and surrounds the entire pulp...
too, although not as well) via a micromechanical bond. As conservation of tooth structure is a key ingredient in tooth preservation, many dentists prefer placing materials like composite instead of amalgam fillings whenever possible.
Generally, composite fillings are used to fill a carious lesion involving highly visible areas (such as the central incisors or any other teeth that can be seen when smiling) or when conservation of tooth structure is a top priority.
The bond of composite resin to tooth, is especially affected by moisture contamination and cleanliness of the prepared surface. Other materials can be selected when restoring teeth where moisture control techniques are not effective.
Glass Ionomer Cement
These fillings are a mixture of glassGlass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
and an organic acid. Although they are tooth-colored, glass ionomers vary in translucency. Although glass ionomers can be used to achieve an aesthetic result, their aesthetic potential does not measure up to that provided by composite resins.
The cavity preparation of a glass ionomer filling is the same as a composite resin; it is considered a fairly conservative procedure as the bare minimum of tooth structure should be removed.
Conventional glass ionomers are chemically set via an acid-base reaction. Upon mixing of the material components, there is no light cure needed to harden the material once placed in the cavity preparation. After the initial set, glass ionomers still need time to fully set and harden.
Glass ionomers do have their advantages over composite resins:
1. They are not subject to shrinkage and microleakage, as the bonding mechanism is an acid-base reaction and not a polymerization reaction.
2. Glass ionomers contain and release fluoride
Fluoride
Fluoride is the anion F−, the reduced form of fluorine when as an ion and when bonded to another element. Both organofluorine compounds and inorganic fluorine containing compounds are called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are...
, which is important to preventing carious lesions. Furthermore, as glass ionomers release their fluoride, they can be "recharged" by the use of fluoride-containing toothpaste. Hence, they can be used as a treatment modality for patients who are at high risk for caries. Newer formulations of glass ionomers that contain light-cured resins can achieve a greater aesthetic result, but do not release fluoride as well as conventional glass ionomers.
Glass ionomers are about as expensive as composite resin. The fillings do not wear as well as composite resin fillings. Still, they are generally considered good materials to use for root caries and for sealants.
Resin modified Glass-Ionomer Cement (RMGIC)
A combination of glass-ionomer and composite resin, these fillings are a mixture of glassGlass
Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...
, an organic acid, and resin polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...
that harden when light cured. (The light activates a catalyst in the cement that causes it to cure in seconds.) The cost is similar to composite resin. It holds up better than glass ionomer, but not as well as composite resin, and is not recommended for biting surfaces of adult teeth.
In general, resin modified glass-ionomer cements can achieve a better aesthetic result than conventional glass ionomers, but not as good as pure composites. It has its own setting reaction.
Compomers
Again a combination of Composite resin and glass ionomer technology, however with the focus lying towards the composite resin end of the spectrum. Has better mechanical and aesthetic properties than RMGIC but worse wear and requires a bonding system to be used. Although compomers release fluoride, they do so at such a low level that it is not deemed effective, and unlike glass ionomer and RMIC cannot act as a fluoride reservoir.Porcelain (ceramic)
PorcelainPorcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...
fillings are hard, but can cause wear on opposing teeth. They are brittle and are not always recommended for molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
fillings.
Gold
Gold fillings have excellent durability, wear well, and do not cause excessive wear to the opposing teeth, but they do conduct heat and cold, which can be irritating. There are two categories of gold fillings, cast gold fillings (gold inlays and onlays) made with 14 or 18 kt gold, and gold foil made with pure 24 kt gold that is burnished layer by layer. For years, they have been considered the benchmark of restorative dental materials. Recent advances in dental porcelains and consumer focus on aesthetic results have caused demand for gold fillings to drop in favor of advanced composites and porcelain veneers and crowns. Gold fillings are sometimes quite expensive; yet, they do last a very long time - which can mean gold restorations are less costly and painful in the long run. It is not uncommon for a gold crown to last 30 years.Other historical fillings
Lead fillings were used in the 18th century, but became unpopular in the 19th century because of their softness. This was before lead poisoningLead poisoning
Lead poisoning is a medical condition caused by increased levels of the heavy metal lead in the body. Lead interferes with a variety of body processes and is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems...
was understood.
According to American Civil War
American Civil War
The American Civil War was a civil war fought in the United States of America. In response to the election of Abraham Lincoln as President of the United States, 11 southern slave states declared their secession from the United States and formed the Confederate States of America ; the other 25...
-era dental handbooks from the mid-19th century, since the early 19th century metallic fillings had been used, made of lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
, tin
Tin
Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...
, platinum
Platinum
Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...
, silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, aluminum, or amalgam
Amalgam (dentistry)
Amalgam is an alloy containing mercury. The term is commonly used for the amalgam employed as material for dental fillings, which consists of mercury , silver , tin , copper , and other trace metals...
. A pellet was rolled slightly larger than the cavity, condensed into place with instruments, then shaped and polished in the patient's mouth. The filling was usually left "high", with final condensation — "tamping down" — occurring while the patient chewed food. Gold foil was the most popular and preferred filling material during the Civil War. Tin and amalgam were also popular due to lower cost, but were held in lower regard.
One survey of dental practices in the mid-19th century catalogued dental fillings found in the remains of seven Confederate soldiers from the U.S. Civil War; they were made of:
- GoldGoldGold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
foilFoil (chemistry)A foil is a very thin sheet of metal, usually made by hammering or rolling a piece of metal. Foils are most easily made with malleable metals, such as aluminium, copper, tin, and gold. Foils usually bend under their own weight and can be torn easily. The more malleable a metal, the thinner foil can...
: Preferred because of its durability and safety. - PlatinumPlatinumPlatinum is a chemical element with the chemical symbol Pt and an atomic number of 78. Its name is derived from the Spanish term platina del Pinto, which is literally translated into "little silver of the Pinto River." It is a dense, malleable, ductile, precious, gray-white transition metal...
: Was rarely used because it was too hard, inflexible and difficult to form into foil. - Aluminum: A material which failed because of its lack of malleability but has been added to some amalgams.
- TinTinTin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...
and ironIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
: Believed to have been a very popular filling material during the Civil War. Tin foil was recommended when a cheaper material than gold was requested by the patient, however tin wore down rapidly and even if it could be replaced cheaply and quickly, there was a concern, specifically from HarrisChapin A. HarrisChapin Aaron Harris A.M., M.D., D.D.S. was an American physician and dentist and dentistry school founder.-Education:...
, that it would oxidise in the mouth and thus cause a recurrence of caries. Due to the blackening, tin was only recommended for posterior teeth. - ThoriumThoriumThorium is a natural radioactive chemical element with the symbol Th and atomic number 90. It was discovered in 1828 and named after Thor, the Norse god of thunder....
: Radioactivity was unknown at that time, and the dentist probably thought he was working with tin. - LeadLeadLead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
and tungstenTungstenTungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...
mixture, probably coming from shotgun pellets. Lead was rarely used in the 19th century, it is soft and quickly worn down by mastication, and had known harmful health effects.
Failure of dental restorations
Fillings have a finite lifespan: an average of 12.8 years for amalgam and 7.8 years for composite resins.One advantage of gold restorations is longevity, because gold can outlast other materials by three to five times longer. When describing other materials, dentists talk in terms of years of service, whereas with cast gold, dentists speak of decades of service. To achieve the greatest longevity, gold dental work must be done with sufficient skill and precision, so discerning patients should seek gold dentists with quality training, experience and expertise.
Fillings fail because of changes in the filling, tooth or the bond between them.
Amalgam fillings expand with age, possibly cracking the tooth and requiring repair and filling replacement. Composite fillings shrink with age and may pull away from the tooth allowing leakage. Quality dental gold is the most biocompatible material used in dentistry today, being non-corrosive and hypo-allergenic. Dental gold’s wear rates and coefficient of thermal expansion is very similar to tooth enamel, which minimizes gaps, leakage or repair due to expansion differentials over time.
As chewing applies considerable pressure on the tooth, the filling may crack, allowing seepage and eventual decay in the tooth underneath. Gold margins do not break or chip even when thinned and polished, and can maintain microscopic gaps even smaller than the diameter of bacterium that cause tooth decay.
The tooth itself may be weakened by the filling and crack under the pressure of chewing. That will require further repairs to the tooth and replacement of the filling. On the other hand, less tooth structure is removed when preparing teeth for gold dental restoration, which leaves the tooth stronger and healthier.
Gold restorations, if done properly, could last the lifetime of a patient. As life expectancies increase, thoughtful dental material choices become even more important to reduce the number of times that fillings and other restorations must be replaced. Repeated repairs to teeth can lead to pulpal inflammation and necrosis, root canal therapy and the eventual necessity for crowns in lieu of fillings. Restoring a tooth only once, with highly durable, non-toxic, biocompatible materials like gold, can be very appealing to discerning patients, and be less costly and painful in the long run.
If fillings leak or if the original bond is inadequate, the bond may fail even if the filling and tooth are otherwise unchanged.
Evaluation and regulation of dental materials
The Nordic Institute of Dental MaterialsNordic Institute of Dental Materials
The Nordic Institute of Dental Materials AS is the Nordic Cooperative Body for dental biomaterials. The Institute’s activities in research, materials testing, standardisation and research-based consulting are directed towards dental health services and health authorities in the Nordic countries...
(NIOM) evaluates dental materials in the Nordic countries
Nordic countries
The Nordic countries make up a region in Northern Europe and the North Atlantic which consists of Denmark, Finland, Iceland, Norway and Sweden and their associated territories, the Faroe Islands, Greenland and Åland...
. This research and testing institution are accredited to perform several test procedures for dental products. In Europe, dental materials are classified as medical devices according to the Medical Devices Directive
Medical Devices Directive
The Medical Device Directive is intended to harmonise the laws relating to medical devices within the European Union...
. In USA, the U.S. Food and Drug Administration is the regulatory body for dental products.
See also
- AnesthesiaAnesthesiaAnesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...
- Dental x-ray
- Dental cariesDental cariesDental caries, also known as tooth decay or a cavity, is an irreversible infection usually bacterial in origin that causes demineralization of the hard tissues and destruction of the organic matter of the tooth, usually by production of acid by hydrolysis of the food debris accumulated on the...
- DentistryDentistryDentistry is the branch of medicine that is involved in the study, diagnosis, prevention, and treatment of diseases, disorders and conditions of the oral cavity, maxillofacial area and the adjacent and associated structures and their impact on the human body. Dentistry is widely considered...
- Oral hygieneOral hygieneTeeth cleaning is part of oral hygiene and involves the removal of dental plaque from teeth with the intention of preventing cavities , gingivitis, and periodontal disease. People routinely clean their own teeth by brushing and interdental cleaning, and dental hygienists can remove hardened...
- Tooth brushingTooth brushingTooth brushing is the act of cleaning teeth with a toothbrush.Modern medical research has shown that brushing teeth properly can prevent cavities, and periodontal, or gum disease, which causes at least one-third of adult tooth loss. If teeth are not brushed correctly and frequently, it could lead...