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Dec 27, 2016

Choice of material

Caries and cracks
The most common reasons for teeth to require fillings are caries and cracks. However, the most durable tooth is an intact one, without any filling. The first time a tooth gets a filling, it usually lasts a long time. But, as fillings get replaced, the tooth becomes weaker. This also depends on which filling material is used.

Types of fillings

Amalgam is a material that will last a long time when a tooth is filled for the first time. It is common to have amalgams that are over 20 years old. An amalgam filling will normally be done in one visit.

When a decayed tooth needs to be filled with amalgam, the dentist will begin by removing the decayed part. If the dentist fills the prepped tooth straight away, the amalgam would soon fall out, as it is not possible to bond the amalgam to the tooth. Therefore, the dentist has to prepare the tooth with a cavity larger at the bottom than at the top.

Usually, when the amalgam sets, it expands and becomes “trapped” in the tooth. Then, later during eating, the filling is pushed downwards, stressing the walls of the tooth and small cracks are created. Eventually this will lead to a collapse of a wall of the tooth and the tooth will be more complicated to fill.

Amalgam becomes “trapped” in the tooth. Over time, the wall of the tooth will collapse.

A composite filling is usually done in one visit. Composites are tooth coloured. In contrast to amalgam, a composite filling can be bonded to the tooth. This means that the tooth will not need the same degree of preparation compared to amalgam fillings. When setting, a composite will not expand, instead it will shrink. It is a huge advantage that composites bond to teeth, but for the bond to be strong, it requires a dry, isolated cavity. This is why composites are technically more demanding than amalgam fillings.

It is an advantage that composites can bond to the tooth so only the deceased part of the tooth is removed

With larger cavities it is a better to proceed with an inlay/crown

If the caries is situated at the side of a tooth facing the tooth next to it, filling it with a composite can be very difficult. Not only should the cavity be closed, but the contact point between the decayed tooth and the neighbouring tooth must be recreated. Without a contact point, a small gap between the teeth could lead to food collection and additional infections, if the space is not cleaned on a regular basis. An inlay/crown can be a solution here.

The composite filling failed to recreate the contact point between the teeth and food will get trapped when eating. An inlay/crown will solve the problem

The recommended restoration for larger cavities is an inlay or onlay, which is completed over two dental visits. Unlike standard fillings that are done at the clinic, both are made at our laboratory and bonded to the tooth during a second visit.

An inlay is done by filling the space between the cusps, or rounded edges, at the centre of the tooth. If the walls are very thin, the inlay can be made to cover the walls and one or more cusps, in order to protect it from cracks. This is called an onlay. Inlays and onlays are made of either gold or ceramic.

A gold inlay is amongst the most durable of fillings. Gold inlays have been around for a long time and results have proved its longevity.

An inlay fills the cavity more precisely than a filling. Materials of choice are ceramic, gold or composite.

Ceramic or porcelain, as it is often called, is tooth coloured. The result is a very natural looking tooth. Since the beginning of the ’80s ceramics have been used for inlays to the tooth. Bonding the ceramic to the tooth is a complicated treatment compared to the gold inlay.

Inlay                                                                                       Onlay

Fit of inlay                                                                           Fit of onlay

If the majority of the crown of the tooth is missing after a caries removal, a crown is the best option. Like the inlay, the crown is made at our laboratory and it involves two visits to the dentist to be set. The crown is placed as a cap on the tooth, protecting it from further cracks in the future. Crowns are made of porcelain or gold.

Although considered the best material for crowns, gold is not that popular anymore and today’s crowns are almost entirely made of porcelain materials, bonded to the tooth in the same way as inlays.

Tooth prepared for crown                                              Fit of crown

Popular filling materials
Today, composite is a very popular filling material. It is usually done in one visit. The durability is dependent on the size of the cavity. The larger the cavity, the shorter the lifespan of the composite filling. In these cases, inlays or crowns of ceramic might also be considered.

Learn more about our services in teeth restorations