Fillings are used to restore our teeth, to ensure they continue to function well, and have lasting integrity and strength. There are a number of types of corrective procedures dental technicians use depending on the state of the tooth and the location of the repair.
Inlays and Onlays
Inlays are used to fill a cavity within a tooth or to fill an area where decayed material was removed. The inlay serves to return strength and integrity to the tooth as well as ensure that future decay cannot occur. Inlays are often produced from gold or porcelain using highly precise and sophisticated techniques to ensure longevity and comfort for the patient.
Onlays are essentially the replacement of missing cusps on the tooth. Metal restorations, which have carefully been produced and created from templates of the patients existing teeth, are laid on to the existing tooth and then finished. The pieces are not manufactured in the patient’s mouth, but by a dental laboratory using castings taken from the patient’s tooth. Onlays are typically made from gold or porcelain and can be very precisely manufactured to the point that the transition from tooth to manufactured repair is seamless.
Metal Occlusal Onlays
Metal occlusal onlays are used in dentistry to restore teeth when a direct restoration is not a reasonable option. “Occlusal force” is the term used by dentists to describe biting forces and occlusal surfaces are the parts of the teeth that come in direct contact with each other. When the term occlusal is used in relation to a repair, the occlusal is the surface on which the repairs are being applied. A metal occlusal onlay is a specific type of repair using gold or porcelain to repair the occlusal surface.
Since the occlusal is subject to extremely high forces where two teeth meet and compress, the materials and procedures applied to the occlusal surface need to be both extremely strong as well as precise. Quite often, an intra-coronal restoration may be used to repair the occlusal surface. However, if the decay or damage to the tooth is so severe, this type of restoration can be inadequate or simply not strong enough for the location on which the repair is being applied.
Amalgam Fillings and Composite Fillings
Amalgam fillings are produced from a combination of mercury and at least one other metal and are the oldest form of dental filler dating back to the 1800s. Amalgam fillings are cost-effective, durable, have good strength properties and are easy to apply.
Composite fillings have become much more common in recent times since they do not possess the same potential health risks that mercury-based amalgam fillers do; nor do they possess any negative environmental effects or by-products from production or material waste.
The material used in composite fillings is a synthetic type of resin, preferred over traditional fillers, due to its many advantageous properties. Composite fillings are insoluble, inexpensive, and resistant to dehydration, making them ideal for use in dentistry. As well, composite fillings are more aesthetically pleasing, since the color is more easily matched to the natural color of the teeth to which they are being applied.
Amalgam fillings are quicker to apply and are considered to be longer lasting than composite fillings. If a composite filling is not carefully and precisely placed, it may fail prematurely. A clean dry surface is extremely important during application, as are the steps taken since the layers need to be built-up and not applied all at once. Composite fillings have come a long way in recent years as their quality continues to increase. Amalgam fillings are gradually being phased out in most western countries.