Inlays and Dental Fillings – High-Quality, Long-Lasting Solutions for Your Teeth Through Dental Fillings, Inlays, and Onlays

Dental fillings and inlays are used to seal a cavity.

Often, a hole remains in the tooth structure after removing tooth decay. The dentist must fill this hole to prevent decay from forming again in the tooth. Sometimes, a tooth defect exposes the tooth’s nerve endings. In such cases, a filling helps prevent pain and inflammation.

A dental filling or inlay can also restore the full chewing function of the teeth. This is particularly important for molars. Proper chewing function prevents irregular wear of the enamel.

Various filling materials and techniques can be used for dental fillings. Which one is best in each individual case depends, among other things,

• the affected tooth,
• the type, location, and size of the damage to the tooth, and
• the patient’s financial situation or insurance status

.

The most suitable material is determined

• on its physical properties, such as durability and strength, as well as
• on the aesthetic aspect, i.e., the color of the filling material.

Your dentist will advise you on these options.

Typical materials for small fillings are

• composite for use in the anterior and posterior regions,
• amalgam in the posterior region, and
• simple dental cement for children and in non-visible areas, such as under the gums.

Illustration of various dental filling materials © SciePro | AdobeStock

For large fillings, there is a wider range of options. Typically, amalgam continues to be used only in the posterior region. Composite and ceramic are used on all teeth. Due to the aesthetic qualities of composite, these materials are particularly popular for the front teeth. Cement continues to be used for all children’s teeth. However, it also serves as a base for a crown or a gold inlay. Gold inlays are usually used only in the posterior region for aesthetic reasons.

Composites are tooth-colored filling materials. They are also referred to as plastic fillings. Due to their nature and texture, they are often confused with ceramic fillings.

Most composites consist of acrylate-based plastics that contain

• glass-ceramic particles,
• silicates, or
• silicon dioxide

as fillers.

Composite fillings are available in several colors. With careful color selection, composite fillings are virtually indistinguishable from the natural color of the surrounding teeth.

Just like an amalgam filling, a composite filling is a plastic filling. It consists of a paste that is applied in small portions to the prepared cavity in the tooth and then shaped. Composite shrinks during curing. Therefore, it must be applied in layers. To cure the composite, dentists use a polymerization lamp (also known as a cold light lamp).

The advantages of composite fillings lie in

• the material’s ease of use and
• the aesthetic effect of its tooth-like color.

Although the material is more expensive than amalgam, it is more affordable than comparable tooth-colored ceramic inlays. The cost per composite filling is approximately 160 €. Statutory health insurance plans cover the costs only

• if used on the front teeth or
• in cases of a proven allergy to amalgam

. Otherwise, the health insurance provider pays only a subsidy equal to the cost of an amalgam filling.

A significant disadvantage of composite fillings, however, is their lower durability and corrosion resistance. In this regard, composite performs worse than amalgam and other metal fillings. With high-quality composite material, the filling is expected to last about 10 years.

Due to the shrinkage of the composite during curing, small gaps form between the tooth surface and the filling, particularly on the sides of the teeth. These gaps provide an ideal environment for new cavities to form. Occasionally, the fillings also become discolored due to frequent consumption of tea, coffee, or tobacco. This diminishes the aesthetic appeal of the composite.

On the left, the tooth affected by caries; on the right, after treatment and a composite filling © Сергей Кучугурный | AdobeStock

Dental cements are prepared by mixing a powder with a liquid. This creates a moldable mass. The dentist applies it directly to the cavity, where the cement hardens.

There are many different types of cements used in dentistry, depending on the type and location of the treatment. For children, cements are the most common filling materials today. They are inexpensive and perfectly suited to the needs of a child’s teeth. They do not cause any health issues. Therefore, a cement filling is usually the best choice for growing children and adolescents.

For adults, cement is used in most cases as a temporary solution. For example, cement is used as a temporary restoration in two-stage treatments. During the first appointment, the tooth is prepared for a gold or ceramic inlay, but the final inlay must first be fabricated. Until the inlay is fitted, cement can fill the cavity in the tooth.

Cement is also frequently used as an additional filling material for particularly large and deep cavities. These so-called underfillings, placed beneath the actual filling, are intended to prevent toothaches. They protect the dental pulp from chemical irritants and insulate it against high and low temperatures.

An amalgam filling is a silvery-gray dental filling made of mercury alloys. It is prepared by mixing approximately 50% pure mercury with approximately 50% of a specific filler mixture. This filler mixture consists of

• at least 40% silver,
• a maximum of 32% tin,
• a maximum of 30% copper,
• a maximum of 5% indium,
• no more than 3% mercury, and
• no more than 2% zinc

combined. This amalgam mixture owes its name—silver amalgam—to its high silver content. Due to the high silver content, the amalgam mixture is more corrosion-resistant than earlier amalgam fillings, such as copper amalgam. Today, this mixture is the only amalgam filling material still in use.

The advantage of amalgam as a dental filling material lies in its relatively easy handling, even under difficult conditions. Its durability is also a major advantage. To date, no other filling material can match the durability of amalgam. It is expected to last up to 10 years, and with good oral hygiene, even up to 20 years or longer.

At the same time, amalgam is considerably less expensive than other modern composite fillings. For this reason, amalgam is the only material fully covered by public health insurance.

A significant disadvantage of amalgam fillings, however, is their conspicuous silvery-gray color. If a large area of amalgam remains in the tooth for several years, the tooth often becomes discolored and turns gray around the filling.

For purely aesthetic reasons, many patients today choose not to have amalgam fillings. Instead, they usually opt for composite fillings, even though these involve additional costs.

A major component of amalgam fillings is toxic mercury. Consequently, discussions about potential health risks arose very early on. These discussions have been ongoing for well over 200 years. To date, however, none of the scientific studies conducted has demonstrated a significant health risk.

The body does not absorb more mercury from dental fillings than it does from daily food intake. Both are classified by the WHO as not harmful to health. Amalgam is the most thoroughly researched dental filling material worldwide. On this basis, amalgam fillings are considered safe and reliable.

A high-quality alternative to composite fillings is the gold inlay, though it does come at a price.

The gold inlay is not made of pure gold, as pure gold is too soft to serve as a suitable dental restoration material. It is simply a gold alloy. It consists of about three-quarters gold and one-quarter silver, copper, or platinum.

Unlike amalgam or composite fillings, a gold filling is not a plastic filling. Instead, it is an inlay. It is fabricated off-site by a dental technician.

Therefore, at least two appointments are necessary to fit and place a gold inlay. During the first appointment

• the dentist removes the decay,
• cleans the tooth,
• takes an impression of the newly created cavity in the tooth, and
• then places a temporary filling (usually made of cement).

During the second appointment, the dentist first removes the temporary filling. He then places the gold inlay and secures it with a special adhesive cement.

The main advantage of gold inlays is their long lifespan of up to 20 years. The gold alloy is hard, corrosion-resistant, and virtually indestructible. Gold inlays

• therefore withstand high chewing pressure well and
• do not develop cracks like composite and amalgam, and
• are highly biocompatible, meaning allergic reactions are unlikely.

One disadvantage of gold inlays, however, is their aesthetic appearance. Especially in the front region or on the outer surfaces of the teeth, the gold stands out very noticeably due to its shine.

Gold hammer fillings have become something of a rarity these days. They are the precursors to gold inlays and have been in use since the 17th century.

The hammered gold filling is a very labor-intensive type of filling. It can only be used for small defects. Unlike inlays, pure gold is used here, either in the form of foil (gold leaf) or as a small sponge. Using a tapping technique, the dentist applies the gold layer by layer to the tooth, thereby sealing the defect.

Because gold is easily malleable, a process known as “cold welding” occurs as the gold is hammered into place. The material is pressed into the defect under pressure. As a result, it exerts a slight elastic tension on the edges of the defect. If the tooth then deforms under stress (e.g., during chewing), no marginal gaps occur. Instead, the gold deforms elastically along with the tooth.

This property fundamentally distinguishes the gold hammer filling from all other filling techniques and materials. It is also one reason for its enormous durability of up to 30 years.

A ceramic inlay is a filling type of equally high quality as a gold inlay. The fitting and placement are performed in two appointments, similar to a gold filling. First, the decay is removed, the cavity is cleaned, an impression is taken, and a temporary filling is placed. Like the gold inlay, the ceramic inlay is fabricated by a dental technician based on the dental impression. It is then fitted during the second appointment.

Unlike a gold inlay, no cement is used to secure a ceramic inlay. Instead, a sophisticated bonding technique is employed. This prevents gaps from forming between the tooth and the inlay.

This opens up additional applications for ceramic inlays. For example, some teeth are not stable enough to support a cemented gold inlay. In such cases, a partial crown would be necessary. Thanks to the inlay’s special bonding technique, the tooth gains new stability from the inside.

Ceramic is considered the gold standard in filling technology. It is comparable to natural tooth structure

• in terms of hardness,
• color, and
• translucency

. A well-fitted, professionally crafted ceramic filling is virtually indistinguishable from a natural tooth. It blends seamlessly into the human dentition. With a high-quality ceramic inlay and good oral hygiene, the inlay is expected to last about 10 years.

However, ceramic inlays also have disadvantages. Their durability does not match that of gold inlays. Inlays covering particularly large areas often break. They are therefore completely unsuitable for patients who frequently grind their teeth.

Replacing broken ceramic inlays is very time-consuming due to the special bonding technique required. In addition, a significant amount of healthy tooth structure must be removed. Furthermore, in some cases, irritation or allergic reactions to the adhesive used may occur. The ceramic inlay must then be removed immediately.

Ceramic inlays are by far the most expensive type of dental filling. Depending on the size and quality of the filling, you can expect costs ranging from €400 to €700.

Inlays and onlays are a high-quality solution for a cavity in a tooth, as they are particularly durable compared to composite fillings or traditional dental fillings. While amalgam fillings are still used, many patients opt for ceramic inlays, which are custom-made by a dental technician as inlay restorations or dental prostheses and cemented into place.

Composite fillings are often used for smaller defects, while gold onlays, inlays, or gold inlays are typically chosen for larger defects. In addition to their natural tooth color and tooth-colored appearance, the advantages and disadvantages of inlays and dental fillings also include factors such as anesthesia, rubber dam, bonding to the tooth surface, and durability—particularly in the front teeth. Statutory health insurance usually covers only the cost of amalgam fillings, which is why the cost of high-quality inlays, ceramic fillings, or gold inlays must be considered on a case-by-case basis.

Depending on the diagnosis, different types of inlays and dental fillings are available, with inlays or onlays often being more durable than conventional dental fillings. In some cases, a temporary filling is placed first before the final restoration with ceramic or gold is completed, to ensure optimal treatment and an aesthetic result.