Dental restoration
[3] Graeco-Roman literature, such as Pliny the Elder's Naturalis Historia (AD 23–79), contains references to filling materials for hollow teeth.
Intracoronal preparations are also made as female recipients to receive the male components of removable partial dentures.
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.
However, sectional matrices can be more technique sensitive to use, so care and skill is required to prevent problems occurring in the final restoration.
Next, the specific software takes the digital picture and converts it into a 3D virtual model on the computer screen.
Another fabrication method is to import STL and native dental CAD 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.
Titanium, usually commercially pure but sometimes a 90% alloy, is used as the anchor for dental implants as it is biocompatible and can integrate into bone.
[12] Other metals and small amounts of minor elements such as zinc, mercury, palladium, platinum and indium are also present.
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.
Dental amalgam is also radiopaque which is beneficial for differentiating the material between tooth tissues on radiographs for diagnosing secondary caries.
Hence, alternative resin-based or glass-ionomer cement-based materials are used instead for smaller restorations including pit and small fissure caries.
Although rarely used today, due to expense and specialized training requirements, gold foil can be used for direct dental restorations.
Dental composites, commonly described to patients as "tooth-colored fillings", are a group of restorative materials used in dentistry.
[12] Inorganic filler such as silica, quartz or various glasses, are added to reduce polymerization shrinkage by occupying volume and to confirm radio-opacity of products due to translucency in property,[clarification needed] which can be helpful in diagnosis of dental caries around dental restorations.
An initiator package[clarification needed] begins the polymerization reaction of the resins when external energy (light/heat, etc.)
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.
[14] 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.
It can be applied as fissure sealant, placed in endodontic access cavity as a temporary filling and a luting agent.
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.
[15][16] Compomers cannot adhere directly to tooth tissue like glass ionomer cements; they require a bonding agent like dental composites.
[18] Some of the materials used are glass-bonded porcelain (Vitablock), lithium disilicate glass-ceramic (a ceramic crystallizing from a glass by special heat treatment), and phase stabilized zirconia (zirconium dioxide, ZrO2).
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 product) also has the fracture resistance needed for use on molars.
[19] 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.
[23] 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.
[citation needed] This can result in short term sensitivity to cold and hot substances, and pain when biting down on the specific tooth.
