Dental restoration, dental fillings, or simply fillings are treatments used to restore the function, integrity, and morphology of missing
tooth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...
structure resulting from
caries
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
or external trauma as well as to the replacement of such structure supported by
dental implant
A dental implant (also known as an endosseous implant or fixture) is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, or facial prosthesis or to act as an orthodo ...
s. They are of two broad types—''direct'' and ''indirect''—and are further classified by location and size. A
root canal filling, for example, is a restorative technique used to fill the space where the
dental pulp
The pulp is the connective tissue, nerves, blood vessels, and odontoblasts that comprise the innermost layer of a tooth. The pulp's activity and signalling processes regulate its behaviour.
Anatomy
The pulp is the neurovascular bundle centr ...
normally resides.
Tooth preparation
Restoring a tooth to good form and function requires two steps:
# preparing the tooth for placement of restorative material or materials, and
# placement of these materials.
The process of preparation usually involves cutting the tooth with a rotary dental handpiece and dental
burrs, a
dental laser A dental laser is a type of laser designed specifically for use in oral surgery or dentistry.
In the United States, the use of lasers on the gums was first approved by the Food and Drug Administration in the early 1990s, and use on hard tissue lik ...
, or though
air abrasion Air abrasion is a dental technique that uses compressed air to propel a thin stream of abrasive particles—often aluminum oxide or silica—through a specialized hand-piece to remove tooth tissue and decay before being suctioned away, similar to s ...
to make space for the planned restorative materials and to remove any
dental decay
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
or portions of the tooth that are structurally unsound. If permanent restoration cannot be carried out immediately after tooth preparation,
temporary restoration
Temporary restoration is a temporary filling of a prepared tooth until permanent restoration is carried out. It is used to cover the prepared part of the tooth, in order to maintain the occlusal space and the contact points, and insulation of the ...
may be performed.
The prepared tooth, ready for placement of restorative materials, is generally called a ''tooth preparation''. Materials used may be
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile me ...
,
amalgam
Amalgam most commonly refers to:
* Amalgam (chemistry), mercury alloy
* Amalgam (dentistry), material of silver tooth fillings
** Bonded amalgam, used in dentistry
Amalgam may also refer to:
* Amalgam Comics, a publisher
* Amalgam Digital
...
,
dental composite
Dental composite resins (better referred to as "resin-based composites" or simply "filled resins") are dental cements made of synthetic resins. Synthetic resins evolved as restorative materials since they were insoluble, of good tooth-like appea ...
s,
glass ionomer cement
A glass ionomer cement (GIC) is a dental restorative material used in dentistry as a filling material and luting cement, including for orthodontic bracket attachment. Glass-ionomer cements are based on the reaction of silicate glass-powder (calc ...
, or
porcelain
Porcelain () is a ceramic material made by heating substances, generally including materials such as kaolinite, in a kiln to temperatures between . The strength and translucence of porcelain, relative to other types of pottery, arises main ...
, among others.
Preparations may be intracoronal or extracoronal. Intracoronal preparations are those which serve to hold restorative material within the confines of the structure of the
crown
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
of a tooth. Examples include all classes of cavity preparations for composite or amalgam as well as those for gold and porcelain
inlay
Inlay covers a range of techniques in sculpture and the decorative arts for inserting pieces of contrasting, often colored materials into depressions in a base object to form Ornament (art), ornament or pictures that normally are flush with th ...
s. Intracoronal preparations are also made as female recipients to receive the male components of
removable partial denture
A removable partial denture (RPD) is a denture for a partially edentulous patient who desires to have replacement teeth for functional or aesthetic reasons and who cannot have a bridge (a fixed partial denture) for any reason, such as a lack of ...
s. Extracoronal preparations provide a core or base upon which restorative material will be placed to bring the tooth back into a functional and aesthetic structure. Examples include
crowns
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
and
onlays, as well as
veneers.
In preparing a tooth for a restoration, a number of considerations will determine the type and extent of the preparation. The most important factor to consider is
decay
Decay may refer to:
Science and technology
* Bit decay, in computing
* Software decay, in computing
* Distance decay, in geography
* Decay time (fall time), in electronics
Biology
* Decomposition of organic matter
* Tooth decay (dental caries ...
. For the most part, the extent of the decay will define the extent of the preparation, and in turn, the subsequent method and appropriate materials for restoration.
Another consideration is unsupported tooth structure. When preparing the tooth to receive a restoration, unsupported enamel is removed to allow for a more predictable restoration. While enamel is the hardest substance in the human body, it is particularly brittle, and unsupported enamel fractures easily.
A systematic review concluded that for decayed baby (primary) teeth, putting an off‐the‐shelf metal crown over the tooth (
Hall technique The Hall Technique is a non-invasive treatment for decayed baby back ( molar) teeth. Decay is sealed under preformed (stainless steel) crowns, avoiding injections and drilling. It is one of a number of biologically orientated strategies for managin ...
) or only partially removing decay (also referred to as "selective removal"
) before placing a filling may be better than the conventional treatment of removing all decay before filling. For decayed adult (permanent) teeth, partial removal (also referred to as "selective removal"
) of decay before filling the tooth, or adding a second stage to this treatment where more decay is removed after several months, may be better than conventional treatment.
Direct restorations
This technique involves placing a soft or malleable filling into the prepared tooth and building up the tooth. The material is then set hard and the tooth is restored. Where a wall of the tooth is missing and needs to be rebuilt, a matrix should be used before placing the material to recreate the shape of the tooth, so it is cleansible and to prevent the teeth from sticking together. Sectional matrices are generally preferred to circumferential matrices when placing composite restorations in that they favour the formation of a contact point. This is important to reduce patient complaints of food impaction between the teeth. However, sectional matrices can be more technique sensitive to use, so care and skill is required to prevent problems occurring in the final restoration. The advantage of direct restorations is that they usually set quickly and can be placed in a single procedure. The dentist has a variety of different filling options to choose from. A decision is usually made based on the location and severity of the associated cavity. Since the material is required to set while in contact with the tooth, limited energy (heat) is passed to the tooth from the setting process.
Indirect restorations
![Inlay on model](https://upload.wikimedia.org/wikipedia/commons/2/29/Inlay_on_model.jpg)
In this technique the restoration is fabricated outside of the mouth using the
dental impressions
A dental impression is a negative imprint of hard (teeth) and soft tissues in the mouth from which a positive reproduction (cast or model) can be formed. It is made by placing an appropriate material in a stock or custom dental impression tray w ...
of the prepared tooth. Common indirect restorations include
inlays and onlays
In dentistry, inlays and onlays are used to fill cavities, and then cemented in place in the tooth. This is an alternative to a direct restoration, made out of composite, amalgam or glass ionomer, that is built up within the mouth.Inlays and onl ...
,
crowns
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
,
bridges
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually someth ...
, and
veneers. Usually a
dental technician
A dental technologist (dental laboratory technician) is a member of the dental team who, upon prescription from a dental clinician, constructs custom-made restorative and dental appliances.
There are four major disciplines within dental technol ...
fabricates the indirect restoration from records the dentist has provided. The finished restoration is usually bonded permanently with a
dental cement
Dental cements have a wide range of dental and orthodontic applications. Common uses include temporary restoration of teeth, cavity linings to provide pulpal protection, sedation or insulation and cementing fixed prosthodontic appliances. Recent u ...
. It is often done in two separate visits to the dentist. Common indirect restorations are done using gold or ceramics.
While the indirect restoration is being prepared, a provisory/
temporary restoration
Temporary restoration is a temporary filling of a prepared tooth until permanent restoration is carried out. It is used to cover the prepared part of the tooth, in order to maintain the occlusal space and the contact points, and insulation of the ...
is sometimes used to cover the prepared tooth to help maintain the surrounding dental tissues.
Removable dental prostheses (mainly
dentures
Dentures (also known as false teeth) are prosthetic devices constructed to replace missing teeth, and are supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable ( removable partial denture o ...
) are sometimes considered a form of indirect dental restoration, as they are made to replace missing teeth. There are numerous types of precision attachments (also known as combined restorations) to aid removable prosthetic attachment to teeth, including magnets, clips, hooks, and implants which may themselves be seen as a form of dental restoration.
The
CEREC
CAD/CAM dentistry is a field of dentistry and prosthodontics using CAD/CAM ( computer-aided-design and computer-aided-manufacturing) to improve the design and creation of dental restorations, especially dental prostheses, including crowns, c ...
method is a chairside
CAD/CAM restorative procedure. An optical impression of the prepared tooth is taken using a camera. Next, the specific software takes the digital picture and converts it into a 3D virtual model on the computer screen. A ceramic block that matches the tooth shade is placed in the milling machine. An all-ceramic, tooth-colored restoration is finished and ready to bond in place.
Another fabrication method is to import
STL and native dental
CAD
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve co ...
files into CAD/CAM software products that guide the user through the manufacturing process. The software can select the tools, machining sequences and cutting conditions optimized for particular types of materials, such as titanium and zirconium, and for particular prostheses, such as copings and bridges. In some cases, the intricate nature of some implants requires the use of 5-axis machining methods to reach every part of the job.
Cavity classifications
Greene Vardiman Black
Greene Vardiman Black (1836–1915) was one of the founders of modern dentistry in the United States. He is also known as the father of operative dentistry.
Black was born near Winchester, Illinois on August 3, 1836 to William and Mary Bl ...
classification:
G.V. Black classified the cavities depending on their site:
*Class I Caries affecting pit and fissure, on occlusal, buccal, and lingual surfaces of molars and premolars, and palatal of maxillary incisors.
*Class II Caries affecting proximal surfaces of molars and premolars.
*Class III Caries affecting proximal surfaces of centrals, laterals, and cuspids.
*Class IV Caries affecting proximal including incisal edges of anterior teeth.
*Class V Caries affecting gingival 1/3 of facial or lingual surfaces of anterior or posterior teeth.
*Class VI Caries affecting cusp tips of molars, premolars, and cuspids.
Graham J. Mount's classification:
Mount classified cavities depending on their site and size. The proposed classification was designed to simplify the identification of lesions and to define their complexity as they enlarge.
Site:
* Pit/Fissure: 1
* Contact area: 2
* Cervical: 3
Size:
* Minimal: 1
* Moderate: 2
* Enlarged: 3
* Extensive: 4
Materials used
Alloys
The following casting alloys are mostly used for making crowns, bridges and dentures.
Titanium
Titanium is a chemical element with the Symbol (chemistry), symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resista ...
, usually commercially pure but sometimes a 90% alloy, is used as the anchor for
dental implants as it is
biocompatible
Biocompatibility is related to the behavior of biomaterials in various contexts. The term refers to the ability of a material to perform with an appropriate host response in a specific situation. The ambiguity of the term reflects the ongoing de ...
and can integrate into bone.
;Precious metallic alloys
*
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile me ...
(high purity: 99.7%)
*
gold alloys (with high gold content)
*gold-platina alloy
*silver-palladium alloy
;Base metallic alloys
*
cobalt-chrome
Cobalt-chrome or cobalt-chromium (CoCr) is a metal alloy of cobalt and chromium. Cobalt-chrome has a very high specific strength and is commonly used in gas turbines, dental implants, and orthopedic implants. alloy
*
nickel-chrome
Nichrome (also known as NiCr, nickel-chromium or chromium-nickel) is a family of alloys of nickel, chromium, and often iron (and possibly other elements) commonly used as resistance wire, heating elements in devices like toasters, electrical kett ...
alloy
Amalgam
Amalgams are alloys formed by a reaction between two or more metals, one of which is mercury. It is a hard restorative material and is silvery-grey in colour. One of the oldest direct restorative materials still in use, dental amalgam was widely used in the past with a high degree of success, although recently its popularity has declined due to a number of reasons, including the development of alternative bonded restorative materials, increase in demand for more aesthetic restorations and public perceptions concerning the potential health risks of the material.
The composition of dental amalgam is controlled by the ISO Standard for dental amalgam alloy (ISO 1559).
The major components of amalgam are silver, tin and copper.
Other metals and small amounts of minor elements such as zinc, mercury, palladium, platinum and indium are also present.
Earlier versions of dental amalgams, known as 'conventional' amalgams consisted of at least 65 wt% silver, 29 wt% tin, and less than 6 wt% copper.
Improvements in the understanding of the structure of amalgam post-1986 gave rise to copper-enriched amalgam alloys, which contain between 12 wt% and 30 wt% copper and at least 40 wt% silver.
The higher level of copper improved the setting reaction of amalgam, giving greater corrosion resistance and early strength after setting.
Possible indications for amalgam are for load-bearing restorations in medium to large sized cavities in posterior teeth, and in core build-ups when a definitive restoration will be an indirect cast restoration such as a crown or bridge retainer. Contraindications for amalgam are if aesthetics are paramount to patient due to the colour of the material. Amalgams should be avoided if the patient has a history of sensitivity to mercury or other amalgam components. Besides that, amalgam is avoided if there is extensive loss of tooth substance such that a retentive cavity cannot be produced, or if excessive removal of health tooth substance would be required to produce a retentive cavity.
Advantages of amalgam include durability - if placed under ideal conditions, there is evidence of good long term clinical performance of the restorations. Placement time of amalgam is shorter compared to that of composites and the restoration can be completed in a single appointment. The material is also more technique-forgiving compared to composite restorations used for that purpose. Dental amalgam is also radiopaque which is beneficial for differentiating the material between tooth tissues on radiographs for diagnosing secondary caries. The cost of the restoration is typically cheaper than composite restorations.
Disadvantages of amalgam include poor aesthetic qualities due to its colour. Amalgam does not bond to tooth easily, hence it relies on mechanical forms of retention. Examples of this are undercuts, slots/grooves or root canal posts. In some cases this may necessitate excessive amounts of healthy tooth structure to be removed. Hence, alternative resin-based or glass-ionomer cement-based materials are used instead for smaller restorations including pit and small fissure caries. There is also a risk of marginal breakdown in the restorations. This could be due to corrosion which may result in "creep" and "ditching" of the restoration. Creep can be defined as the slow internal stressing and deformation of amalgam under stress. This effect is reduced by incorporating copper into amalgam alloys. Some patients may experience local sensitivity reactions to amalgam.
Although the
mercury in cured amalgam is not available as free mercury, concern of its toxicity has existed since the invention of amalgam as a dental material. It is banned or restricted in Norway, Sweden and Finland. See
Dental Amalgam Controversy
This discussion of the dental amalgam controversy outlines the debate over whether dental amalgam (the mercury alloy in dental fillings) should be used. Supporters claim that it is safe, effective and long-lasting while critics argue that claim ...
.
Direct gold
Direct gold fillings were practiced during the times of the Civil War in America.
Although rarely used today, due to expense and specialized training requirements, gold foil can be used for direct dental restorations.
Composite resin
![Dental Restoration](https://upload.wikimedia.org/wikipedia/commons/e/e6/Dental_Restoration.jpg)
Dental composites, commonly described to patients as "white fillings", are a group of restorative materials used in dentistry. They can be used in direct restorations to fill in the cavities created by dental caries and trauma, minor buildup for restoring tooth wear (non-carious tooth surface loss) and filling in small gaps between teeth (labial veneer). Dental composites are also used as indirect restoration to make crowns and inlays in the laboratory.
These materials are similar to those used in direct fillings and are tooth-colored. Their strength and durability is not as high as porcelain or metal restorations and they are more prone to wear and discolouration. As with other composite materials, a dental composite typically consists of a resin-based matrix, which contains a modified methacrylate or acrylate. Two examples of such commonly used monomers include
bisphenol A-
glycidyl methacrylate
Glycidyl methacrylate (GMA) is an ester of methacrylic acid and glycidol. Containing both an epoxide and an acrylate groups, the molecule is bifunctional. It is a common monomer used in the production of epoxy resins. While typical home epoxies ...
(BISMA) and
urethane dimethacrylate (UDMA), together with tri-ethylene glycol dimethacrylate (TEGMA). TEGMA is a
comonomer In polymer chemistry, a comonomer refers to a polymerizable precursor to a copolymer aside from the principal monomer. In some cases, only small amounts of a comonomer are employed, in other cases substantial amounts of comonomers are used. Furthe ...
which can be used to control viscosity, as Bis GMA is a large molecule with high viscosity, for easier clinical handling.
Inorganic filler such as
silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is ...
, quartz or various glasses, are added to reduce
polymerization
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many fo ...
shrinkage by occupying volume and to confirm radio-opacity of products due to translucency in property, which can be helpful in diagnosis of dental caries around dental restorations. The filler particles give the composites
wear resistance
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology.
Wear in ...
as well. Compositions vary widely, with proprietary mixes of resins forming the matrix, as well as engineered filler glasses and glass ceramics. A coupling agent such as
silane
Silane is an inorganic compound with chemical formula, . It is a colourless, pyrophoric, toxic gas with a sharp, repulsive smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Sila ...
is used to enhance the bond between resin matrix and filler particles. An initiator package begins the polymerization reaction of the resins when external energy (light/heat, etc.) is applied. For example, camphorquinone can be excited by visible blue light with critical wavelength of 460-480 nm to yield necessary free radicals to start the process.
After
tooth preparation, a thin primer or bonding agent is used. Modern
photo-polymerised composites are applied and cured in relatively thin layers as determined by their opacity. After some curing, the final surface will be shaped and polished.
Glass ionomer cement
A
glass ionomer cement
A glass ionomer cement (GIC) is a dental restorative material used in dentistry as a filling material and luting cement, including for orthodontic bracket attachment. Glass-ionomer cements are based on the reaction of silicate glass-powder (calc ...
(GIC) is a class of materials commonly used in dentistry as direct filling materials and/or for luting indirect restorations. GIC can also be placed as a lining material in some restorations for extra protection. These tooth-coloured materials were introduced in 1972 for use as restorative materials for anterior teeth (particularly for eroded areas).
The material consists of two main components: Liquid and powder. The liquid is the acidic component containing of polyacrylic acid and tartaric acid (added to control the setting characteristics). The powder is the basic component consisting of sodium alumino-silicate glass.
The desirable properties of glass ionomer cements make them useful materials in the restoration of carious lesions in low-stress areas such as smooth-surface and small anterior proximal cavities in primary teeth.
Advantages of using glass ionomer cement:
* The addition of tartaric acid to GIC leads to a shortened setting time, hence providing better handling properties. This makes it easier for the operator to use the material in clinic.
* GIC does not require bond, it can bond to enamel and dentine without the need for use of an intermediate material. Conventional GIC also has a good sealing ability providing little leakage around restoration margins and reducing the risk of secondary caries.
* GIC contains and releases fluoride after being placed therefore it helps in preventing carious lesions in teeth.
* It has good thermal properties as the expansion under stimulus is similar to dentine.
* The material does not contract on setting meaning it is not subject to shrinkage and microleakage.
* GIC is also less susceptible to staining and colour change than composite.
Disadvantages of using Glass ionomer cement:
* GIC have poor wear resistance, they are usually weak after setting and are not stable in water however this improves when time goes on and progression reactions take place. Due to their low strength GICs are not appropriate to be placed in cavities in areas which bear an increase amount of occlusal load or wear.
* The material is susceptible to moisture when it is first placed.
* GIC varies in translucency therefore it can have poor aesthetics , especially noticeable if placed on anterior teeth.
Resin Modified Glass Ionomer
Resin modified glass ionomer was developed to combine the properties of glass ionomer cement with composite technology. It comes in a powder-liquid form. The powder contains fluro-alumino-silicate glass, barium glass (provides radiopacity), potassium persulphate (a redox catalyst to provide resin cure in the dark) and other components such as pigments. The liquid consists of HEMA (water miscible resin), polyacrylic acid (with pendant methacrylate groups) and tartaric acid. This can undergo both acid base and polymerisation reactions. It also has photoinitiators present which enable light curing.
The ionomer has a number of uses in dentistry. It can be applied as fissure sealant, placed in endodontic access cavity as a temporary filling and a luting agent. It can also be used to restore lesions in both primary and permanent dentition. They are easier to use and are a very popular group of materials.
Advantages of using RMGIC:
* Provides a good bond to enamel and dentine.
* It has better physical properties than GIC.
* A Lower solubility in moisture.
* It also releases fluoride over time.
* Provided better translucency and aesthetics as compared to GIC.
* Better handling properties making it easier to use.
Disadvantages of using RMGIC:
* Polymerisation Contraction can cause microleakage around restoration margins
* It has an exothermic setting reaction which can cause potential damage to tooth tissue.
* The material swells due to uptake of water as HEMA is extremely hydrophilic.
* Monomer leaching : HEMA is toxic to the pulp therefore it must be polymerised completely.
* The strength of the material reduces if its not light-cured.
GIC and RMGIC are used in dentistry, there will be times when one of these materials is better than the other but that is dependant upon the clinical situation. However in most cases the ease of use is deciding factor.
Compomer
Dental compomers are another type of white filling material although their use is not as widespread.
Compomers were formed by modifying dental composites with poly-acid in an effort to combine the desirable properties of dental composites, namely their good aesthetics, and glass ionomer cements, namely their ability to release fluoride over a long time. Whilst this combination of good aesthetics and fluoride release may seem to give compomers a selective advantage, their poor mechanical properties (detailed below) limits their use.
Compomers have a lower wear resistance and a lower compressive, flexural and tensile strength than dental composites, although their wear resistance is greater than resin-modified and conventional glass ionomer cements.
Compomers cannot adhere directly to tooth tissue like glass ionomer cements; they require a bonding agent like dental composites.
Compomers may be used as a cavity lining material and a restorative material for non-load bearing cavities.
In Paediatric dentistry, they can also be used as a fissure sealant material.
The luting version of compomer may be used to cement cast alloy and ceramic-metal restorations, and to cement orthodontic bands in Paediatric patients.
However, compomer luting cement should not be used with all-ceramic crowns.
Porcelain (ceramics)
![Onlay](https://upload.wikimedia.org/wikipedia/commons/6/6e/Onlay.jpg)
''Full-porcelain'' dental materials include
dental porcelain
Dental porcelain (also known as dental ceramic) is a dental material used by dental technicians to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers. Evidence suggests they are an effective material as they a ...
(porcelain meaning a high-firing-temperature ceramic), other
ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...
s, sintered-
glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...
materials, and
glass-ceramic
Glass-ceramics are polycrystalline materials produced through controlled crystallization of base glass, producing a fine uniform dispersion of crystals throughout the bulk material. Crystallization is accomplished by subjecting suitable glasses to ...
s as indirect fillings and
crown
A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...
s or metal-free "jacket crowns". They are also used as inlays, onlays, and aesthetic
veneers. A veneer is a very thin shell of porcelain that can replace or cover part of the enamel of the tooth. Full-porcelain restorations are particularly desirable because their color and translucency mimic natural tooth enamel.
Another type is known as ''porcelain-fused-to-metal'', which is used to provide strength to a crown or bridge. These restorations are very strong, durable and resistant to wear, because the combination of porcelain and metal creates a stronger restoration than porcelain used alone.
One of the advantages of computerized dentistry (CAD/CAM technologies) involves the use of machinable ceramics which are sold in a partially
sintered, machinable state that is fired again after machining to form a hard ceramic. Some of the materials used are
glass-bonded porcelain (Vitablock),
lithium disilicate
Lithium disilicate (Li2Si2O5) is a chemical compound that is a glass ceramic. It is widely used as a dental ceramic due to its strength, machinability and translucency.
Use
Lithium disilicate has found applications in dentistry as a dental cera ...
glass-ceramic
Glass-ceramics are polycrystalline materials produced through controlled crystallization of base glass, producing a fine uniform dispersion of crystals throughout the bulk material. Crystallization is accomplished by subjecting suitable glasses to ...
(a ceramic crystallizing from a glass by special heat treatment), and phase stabilized
zirconia
Zirconium dioxide (), sometimes known as zirconia (not to be confused with zircon), is a white crystalline oxide of zirconium. Its most naturally occurring form, with a monoclinic crystalline structure, is the mineral baddeleyite. A dopant sta ...
(zirconium dioxide, ZrO
2). Previous attempts to utilize high-performance ceramics such as zirconium-oxide were thwarted by the fact that this material could not be processed using the traditional methods used in dentistry. Because of its high strength and comparatively much higher fracture toughness, sintered zirconium oxide can be used in posterior crowns and bridges, implant abutments, and root dowel pins. Lithium disilicate (used in the latest Chairside Economical Restoration of Esthetic Ceramics
CEREC
CAD/CAM dentistry is a field of dentistry and prosthodontics using CAD/CAM ( computer-aided-design and computer-aided-manufacturing) to improve the design and creation of dental restorations, especially dental prostheses, including crowns, c ...
product) also has the fracture resistance needed for use on molars. Some all-ceramic restorations, such as porcelain-fused-to-alumina set the standard for high aesthetics in dentistry because they are strong and their color and translucency mimic natural tooth enamel.
Cast metals and porcelain-on-metal were the standard material for crowns and bridges for long time. The full ceramic restorations are now the major choice of patients and are of commonly applied by dentists.
Comparison
*Composites and amalgam are used mainly for direct restoration. Composites can be made of color matching the tooth, and the surface can be polished after the filling procedure has been completed.
*Amalgam fillings expand with age, possibly cracking the tooth and requiring repair and filling replacement, but chance of leakage of filling is less.
*Composite fillings shrink with age and may pull away from the tooth allowing leakage. If leakage is not noticed early, recurrent decay may occur.
*A 2003 study showed that fillings have a finite lifespan: an average of 12.8 years for amalgam and 7.8 years for composite resins.
Fillings fail because of changes in the filling, tooth or the bond between them. Secondary cavity formation can also affect the structural integrity the original filling. Fillings are recommended for small to medium-sized restorations.
* Inlays and onlays are more expensive indirect restoration alternative to direct fillings. They are supposed to be more durable, but long-term studies did not always detect a significantly lower failure rate of ceramic or composite inlays compared to composite direct fillings.
*Porcelain, cobalt-chrome, and gold are used for indirect restorations like crowns and partial coverage crowns (onlays). Traditional porcelains are brittle and are not always recommended for
molar restorations. Some hard porcelains cause excessive wear on opposing teeth.
Experimental
The US National Institute of Dental Research and international organizations as well as commercial suppliers conduct research on new materials. In 2010, researchers reported that they were able to stimulate mineralization of an enamel-like layer of
fluorapatite ''in vivo''. Filling material that is compatible with pulp tissue has been developed; it could be used where previously a root canal or extraction was required, according to 2016 reports.
Restoration using dental implants
Dental implant
A dental implant (also known as an endosseous implant or fixture) is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, or facial prosthesis or to act as an orthodo ...
s are anchors placed in bone, usually made from titanium or titanium alloy. They can support dental restorations which replace missing teeth. Some restorative applications include supporting crowns, bridges, or
dental prostheses.
Complications
Irritation of the nerve
When a deep cavity had been filled, there is a possibility that the nerve may have been irritated. This can result in short term sensitivity to cold and hot substances, and pain when biting down on the specific tooth. It may settle down on its own. If not, then alternative treatment such as
root canal treatment
Root canal treatment (also known as endodontic therapy, endodontic treatment, or root canal therapy) is a treatment sequence for the infected pulp of a tooth which is intended to result in the elimination of infection and the protection o ...
may be considered to resolve the pain while keeping the tooth.
Weakening of tooth structure
In situations where a relatively larger amount of tooth structure has been lost or replaced with a filling material, the overall strength of the tooth may be affected. This significantly increases the risk of the tooth fracturing off in the future when excess force is placed on the tooth, such as trauma or grinding teeth at night, leading to
cracked tooth syndrome
Cracked tooth syndrome (CTS) is where a tooth has incompletely cracked but no part of the tooth has yet broken off. Sometimes it is described as a greenstick fracture. The symptoms are very variable, making it a notoriously difficult condition to d ...
.
See also
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Dental curing light
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Dental dam
A dental dam or rubber dam is a thin, square sheet, usually latex or nitrile, used in dentistry to isolate the operative site (one or more teeth) from the rest of the mouth. Sometimes termed "Kofferdam" (from German), it was designed in the U ...
*
Dental fear
Dental fear, or dentophobia, is a normal emotional reaction to one or more specific threatening stimuli in the dental situation. However, dental anxiety is indicative of a state of apprehension that something dreadful is going to happen in relatio ...
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Dental braces
Dental braces (also known as braces, orthodontic cases, or cases) are devices used in orthodontics that align and straighten teeth and help position them with regard to a person's bite, while also aiming to improve dental health. They are often ...
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Dental treatment
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Fixed prosthodontics
Fixed prosthodontics is the area of prosthodontics focused on permanently attached (fixed) dental prostheses. Such dental restorations, also referred to as indirect restorations, include crowns, bridges (fixed dentures), inlays, onlays, and ve ...
*
Gold teeth
A gold crown
Gold teeth are a form of dental prosthesis where the visible part of a tooth is replaced or capped with a prosthetic molded from gold.
History
The academic paper titled "Gold Work, Filing and Blackened Teeth: Dental Modifications i ...
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Oral and maxillofacial surgery
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Oral and maxillofacial pathology
Oral and maxillofacial pathology refers to the diseases of the mouth ("oral cavity" or "stoma"), jaws ("maxillae" or "gnath") and related structures such as salivary glands, temporomandibular joints, facial muscles and perioral skin (the skin aro ...
*
Treatment of knocked-out (avulsed) teeth
References
External links
How Dental Restoration Materials Compare
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Dental materials
Dentistry procedures
Restorative dentistry