Modern ethos of dental treatment is to treat tooth pain, decayed and broken down teeth by trying to be as minimally invasive and trying to restore the natural tooth. Regarding teeth, nothing is better than holding on to your natural God given teeth.
Teeth can undergo structural damage which require some form of repair. The process of repairing or fixing a tooth is known as a restoration.
MERCURY AMALGAM METAL FILLINGS
This is the NHS standard. Used for many years on the NHS because they work well, historically. However long term metal mercury fillings do tarnish black and do get brittle and hence crumble.
Composite resin dental fillings were researched and made as a better alternative to traditional mercury metal amalgam fillings. They are coloured to look like natural teeth, hence making a tooth look exactly like a tooth. Composite resin fillings are very durable and help make a natural looking smile. Modern scientific studies do actually show that compressive strength of Composite resin is as good as or even better than mercury amalgam metal fillings.
The two main types of inlays and onlays are made from composite resin or porcelain. Gold versions also exist, and metal ones can be done on the NHS. However, the inlays and onlays are often more appealing as porcelain and resin as they can be contoured and coloured to look very natural. Hence dental inlays and onlays a popular choice for those wanting to replace unattractive metal fillings.
This type of dental product is bonded onto the toot as the animation shows. Onlays cover the Cusp, where fracture is possible.