Thanks to improvements in dental materials and techniques, dentists have more options for creating beautiful, natural-looking smiles. After many years of development in ceramics and composites, dentists and patients now have a wider choice of restorative materials to restore damaged teeth.
These new materials have not fully replaced the benefits of some traditional ones, such as gold alloy inlays and amalgam fillings. Their durability and strength make them a suitable choice for back teeth, where chewing forces are greater.
Choosing a material
Several factors affect how long materials last, how well they perform and how much they cost. These factors include: the patient's oral and general health, the composition of the restorative material, the position of the tooth in the dental arch, and the clinical time and number of visits needed to complete the treatment. The material is chosen after a discussion with your dentist.
Types of dental restorations
There are two main types of restorations – direct and indirect.
With direct restorations, the material is placed in the prepared tooth during a single visit. These materials include dental amalgam, glass ionomer cements and composites. The dentist prepares the tooth, places the restorative material and adjusts it in one visit.
Indirect restorations need two or more visits. This group includes inlays, onlays, veneers, crowns and bridges made of metal, composite or ceramic. At the first visit, the dentist prepares the tooth or teeth and takes an impression of the area. The impression is sent to a dental laboratory, where the restoration is made. At the next visit, the finished restoration is cemented and adjusted (fine-tuned).
Amalgam fillings
Used by dentists for more than a century, dental amalgam is the most thoroughly studied and tested restorative material. It is easy to place, highly resistant to wear and relatively cheaper than other materials. For these reasons, amalgam remains a valuable restorative material in certain cases.
Dental amalgam is a stable mixture of mercury, copper, silver and other metals. Although it is a safe and commonly used material, some concerns have been raised about its mercury content. In the material, the mercury is combined with other metals, which make it stable and safe to use. The World Health Organization and other similar organisations consider amalgam a material that is safe for health.
Because dental amalgam restorations are very strong, they are preferred in the back of the dental arch – they are suitable for molars and premolars, where chewing pressure is much greater. They are also useful in areas that are hard to reach and hard to keep free of saliva during filling, such as deep decay below the gum line. Amalgam is a biocompatible material and is preferred for patients at high risk of allergies.
The disadvantages of dental amalgam include short-term sensitivity to hot and cold after it is placed. Its metallic grey colour differs from the natural colour of teeth and is visible, especially further forward in the mouth when you laugh or speak. Preparing a tooth for amalgam often means removing more tooth structure than with other materials.
Composite fillings
Composite materials are a mixture of glass particles and resin that match the colour of natural teeth. They are durable in the mouth and resistant to fracture in smaller restorations, outside areas of heavy chewing pressure. Less tooth structure is removed when the tooth is prepared, and the result is a smaller filling. The price varies and depends on the size of the restoration and the technique used by the dentist. The clinical time needed is longer than for amalgam. Placing a composite requires a dry working area, which is not always possible. Over time, the material changes colour in the mouth and the edges become discoloured.
Glass ionomer cements
Glass ionomers are made of polyacrylic acid and glass particles. They are slightly translucent and imitate the natural colour of teeth. They are used mainly for restorations in the area of the tooth roots. They release small amounts of fluoride ions over a long period, which is an advantage for patients at high risk of tooth decay. Less hard tooth structure is removed when the tooth is prepared than with amalgam. They are used mainly in areas of low chewing pressure, because they do not withstand pressure well and fracture more often. They have low wear resistance. Allergic reactions in patients are rare.
Indirect restorative materials
In some cases, the most suitable solution for the patient is a restoration made individually in a laboratory. This can be an inlay, onlay, crown or bridge, and it requires more than one visit to the clinic. A dental crown covers all the visible surfaces of the tooth. An inlay is a restoration that fits within the contours of the tooth. An onlay is larger than an inlay and also covers part of the chewing surface of the tooth. These restorations cost more than direct ones, because of the longer clinical time, the greater number of visits and the laboratory work. They can be made of ceramic, ceramic on a metal base, gold or other metal alloys.
All-ceramic restorations
Inlays, onlays, crowns and aesthetic veneers can be made entirely of ceramic. A veneer is a thin porcelain shell that replaces or covers part of the tooth enamel. All-ceramic restorations give the best aesthetic effect, because they imitate the colour and translucency of natural teeth so well. All ceramic restorations require at least two visits to the clinic. There is a high risk of fracture when they are placed under pressure. Their resistance to fracture depends directly on the ceramic being thick enough. They are highly wear-resistant, but if they are not polished, they easily wear down the surface of the natural teeth they come into contact with.
Metal-ceramic restorations
Ceramic fused to a metal base combines strength and good looks. The bond between the porcelain and the metal is stronger than the bond between porcelain and the tooth surface. More of the tooth surface has to be removed to make room for the metal and the ceramic. These restorations can also wear down the teeth they come into contact with if the ceramic surface is not well polished. Although the combination of metal and ceramic is biologically well tolerated, some patients report allergic reactions to components of the metal alloy.
Indirect composites
Crowns, inlays and onlays can be made in a laboratory from dental composites. These materials are similar to those used in direct techniques and are tooth-coloured. Their advantage is that they do not wear down the opposing teeth. Their strength and durability are not as high as those of ceramic and metal restorations, and they can become discoloured over time.
The right choice of restorative material depends on the clinical situation, the position in the dental arch, how badly the tooth is damaged, whether the working area can be isolated and kept dry during treatment and, last but not least, the aesthetic requirements of that particular area of the mouth.
This article is for information only and does not replace an examination by a dentist.
