How Composite Veneers are made
Dental composite veneers are made using the same type of materials that are used for cosmetic bonding and for many white fillings. Composite material incorporates a hard filler as small particles in a resin matrix in order to achieve an overall soft, malleable material that can be shaped as required and then set hard by means of a powerful light source that polymerizes the resin. Light curing is generally preferred to chemical, because the material comes ready formed and thus mixing two pastes is not necessary, and not ideal since it can introduce air and subsequent porosity in the restoration. Light cured material as one paste also allows for time to properly shape the composite material and then the ability to set it quickly on command.
Composite fillings are composed of an organic polymer resin called bisphenol-A-glycidyl methacrylate (BIS-GMA), and inorganic particles such as quartz, borosilicate glass, and lithium aluminium silicate. This type of material is tooth coloured and available in a range of shades to match the diverse colours of teeth and is able to be blended so that it becomes indistinguishable from natural tooth substance. Composite also adheres well to the surface of teeth when applied using an acid etch technique, and this means it can be used in lots of ways in building up teeth without having to remove tooth substance, to form onlays, and reshape teeth, as well as for veneers.
The etching of tooth enamel with a 30% orthophosphoric acid gel is a well-established technique to produce a slightly roughened tooth surface which will form a strong physical bond with a low viscosity resin, which then in turn bonds chemically to subsequent layers of more viscous composite applied incrementally. In this way a veneer can be constructed to cover unwanted marks or discolourations on a tooth in a relatively short time and in a completely painless way. Ideally with veneers the overall contour doesn’t want to be too obvious or bulky so the layer of composite needs to be kept thin.
Composite veneers are most often provided directly by your dentist at a single visit where the composite is applied to your tooth surface and then polished to create a smooth, glossy finish. Some time and patience is required to get a good result with composite veneers since it is a precise and exacting technique. A dentist also requires some artistic flair ideally, plus a good working knowledge of the composite material’s properties and how to mix various shades of colour to get a lifelike appearance.
Occasionally composite can be used to create veneers in the dental laboratory and these are then fitted by your dentist at a second visit using a similar bonding technique with low-viscosity light cured resins. This can produce a better result because the veneers made in the laboratory as opposed to directly in the mouth can be made harder by using a more powerful polymerizing light and/or heat to ensure maximum strength, and then a surface glaze can be applied to give a shinier appearance.
Composite resin is a very versatile material and in skilled hands can be used to build up a diminutive front tooth that hasn’t developed properly, build out a tooth that is set slightly in from the others, cover intrinsic spots or marks on a tooth, or even close up a space between front teeth by extending composite filing out from the sides of the teeth either side of the gap.
Composite is not as hard wearing as porcelain, even when laboratory hardened, and so you can expect that the life of composite veneers might not exceed five years or so before they become discoloured or worn and require replacing.
Some problems confronting the dentist such as severely eroded and abraded teeth from excessive consumption of acidic drinks or bulimia were at one time very difficult to deal with, but the bonding of resin composite can often be used to build up the height of short sensitive teeth, and restore their appearance by means of veneers on the front teeth, at least on a temporary basis until it is deemed appropriate perhaps to provide more permanent restorations
The composition of composites has changed over the years to provide harder, denser types that last better in terms of strength and resistance to staining, and it is possible that further improvements will be made. At the present time there are differences between different brands in their composition which can affect their clinical performance. A higher concentration of filler, achievable with smaller particles, gives greater strength and wear resistance but may affect the optical properties so there is some trade-off in terms of getting a good balance. Smaller particles also allow for better polishing of the surface and less likelihood of the resin content being so easily worn away leaving hard granules standing proud and a consequent roughened surface.
It is generally accepted that microfill composites have the most ideal aesthetic qualities, due to their ability to be polished to give a smooth, light-reflecting surface, and so are ideal for the purpose of making composite veneers.
To find out more about composite veneers please call 6297 1303 to make appointment with our cosmetic dentists in Queanbeyan.