The inlay or onlay is a dental restoration of the tooth after a caries or an old amalgam filling has been removed. This is a high-quality and durable repair. The inlay or onlay can be made of various materials and cemented or bonded precisely into the broken tooth.

When selecting materials and materials, it is essential to pay attention to biological compatibility, durability and aesthetics.

Our dental office has its own dental laboratory and specializes in ceramic inlays. The materials are selected in the best possible way from the point of view of biology and durability.

The entire manufacturing process is finely tuned so that the accuracy of fit of inlays can be optimally achieved.

You are welcome to contact us at any time.

Dentist in Winterthur - Dr. Artur Hein

What are inlays and onlays?


Every day, our teeth are exposed to strong chemical and physical stresses. For example, caries can cause a defect in the tooth, which should definitely be restored.

Inlays and onlays consist of one piece and have the task to replace exactly this lost tooth part. Thus, inlays and onlays do not differ in their function, but only in their shape and extension.

Inlays and overlays

An inlay has a small size and supplies the inner part of the occlusal surface. It is always used when the tooth defect is rather smaller.

An onlay expands over the entire occlusal surface of the tooth and is necessary when the defect assumes a larger extent.

When are inlays and onlays used?


 

Every healthy tooth has an ideal anatomy. This ensures that the food is chewed optimally, no food debris gets stuck between the teeth and the jaw joints do not experience any overload.

In various situations it is necessary to repair teeth with inlays or onlays:

1. caries

The acid of some strains of bacteria can etch holes in the tooth. This defect in the tooth should definitely be repaired anatomically correct. Inlays and onlays are a recommended treatment for larger caries.

2. amalgam removal / amalgam restoration

Amalgam fillings have a detrimental effect on health and should definitely be removed under effective protective measures. After removal, the missing tooth substance can be replaced very well with inlays or onlays.

Amalgam removal and ceramic fillings

3. broken off piece of tooth

Occasionally, part of the tooth may break off. Teeth that have already been drilled or that have caries can easily break off when force is applied. The broken piece of the tooth can be restored with a high-quality inlay or onlay.

4. reconstruction of the occlusal surfaces

In patients with incorrect tooth contacts, the temporomandibular joints are very often compressed and forced into a non-physiological position. This causes the temporomandibular joints and surrounding tissues to remodel and can affect the entire body. Such a condition can lead to the clinical picture CMD (Craniomandibular Dysfunction), which can greatly affect the quality of life.

As a therapy, the influence of the pathological tooth contacts must be eliminated by a special splint (MAGO splint), which allows the temporomandibular joints to slowly regenerate. Once the regeneration of the temporomandibular joints is complete, the CMD symptoms should have disappeared completely. To prevent the old bite from harming the regenerated temporomandibular joints, the correct anatomy of the teeth must be restored. This is done by a complete reconstruction of the occlusal surfaces with inlays, onlays and veneers. This reconstruction can also be combined with orthodontics.

 

For simplicity, we use the term inlay in the following part of the article, but the onlay is also included.

What material are inlays made of?


There are various materials and materials for the production of inlays. All of them have their specific advantages and disadvantages, which you should definitely know.

 

Ceramic inlays – Ceramic inlays

Ceramic inlays are also called ceramic fillings. They can be made from different types of ceramics.

Ceramic material is highly recommended in terms of biology, fit, longevity and esthetics. It meets the requirements of high-quality esthetic dentistry.

The accuracy of fit and precision strongly depend on the type of ceramic and the manufacturing process.

During treatment and production, great care must be taken to maintain a minimum layer thickness, otherwise subsequent spalling and chipping may occur.

Provided that an experienced dental and dental technical team performs the dental restoration, an ideal result can be achieved with ceramics.

Gold inlays – Gold inlays

Gold has proven its worth to dentists as a material for inlays over many decades. Gold inlays are very accurate in fit and exhibit high longevity.

However, gold has inferior aesthetic and health properties. The lack of biocompatibility has been reported, among others, by the
IMD Institute for Medical Diagnostics Berlin
, detected in numerous samples and examinations.

Gold and ceramic inlays – Galvanic inlays

This is an inlay that consists of a combination between ceramic and gold. Ceramics make up the largest proportion, with the inner layer facing the tooth made of gold.

Overall, electroplated inlays exhibit a very good fit and high longevity. However, poor biocompatibility remains, which is why electroplated inlays are not recommended.

Titanium inlays – Titanium inlays

Titanium is actually known from
Dental implants
. It is the most commonly used material in implantology.

Titanium inlays have a good fit and high longevity. However, many patients are bothered by the unaesthetic, metallic-greyish color.

Just as with gold, there are several health concerns with titanium.

Plastic inlays – Plastic inlays

There are many different materials that can be used for resin inlays. Depending on the quality of the material and the method of production, the result can vary greatly.

If produced correctly in the dental laboratory with high-quality material, resin inlays can be an alternative to ceramic inlays.

However, plastic does not come close to the biology and stability of ceramic and plays a minor role in inlays.

Note for choosing the right material:

In general, the metallic materials show high thermal conductivity. Thermal conductivity, as the name suggests, describes the ability to transmit temperature. Consequently, teeth that have received a metallic restoration may experience pain with hot and cold foods or beverages.

Ceramics and plastics have low thermal conductivity, which eliminates this disadvantage.

When does an inlay make sense – filling, inlay or crown?


As mentioned above, inlays are used to restore missing parts of teeth, for example after a caries, from one piece. This gives the tooth back its original anatomical shape.

If the caries is small, the defect can be repaired with a classic filling. filling made of plastic can be replaced. In many cases, this is possible without complications.

If the tooth defect is extensive and anatomical reconstruction directly in the mouth is difficult, the Inlay are preferred. In this way, the dental technician can optimally reconstruct the ideal anatomy of the tooth. With a filling, on the other hand, there could be a risk that the contact with the neighboring tooth is too weak and food debris could get stuck there.

If you as a patient prefer the solution with the best tolerability and longest durability, you should choose the ceramic inlay. Ceramic inlays are also ideal in terms of esthetic dentistry.

If the natural crown of the tooth is too badly damaged, then it should be replaced with a crown, preferably made of ceramic, can be stabilized and restored. In such a case, the dental filling and also the inlay would not be the right choice.

Consequently, the correct, individual choice of dental restoration is of great importance so that the stability and anatomy of the teeth can be ideally reproduced. The dentist should always take into account the biology of the material.

How are inlays fixed in the tooth?


Inlays have the function of replacing the missing tooth defect. In order for the missing piece to be fixed, it is cemented or glued into the tooth.

Fastening with cement

There are different cements in dentistry. These adhere to the tooth and the inlay and ensure a firm and definitive bond.

Common cements include glass ionomer cement, zinc oxide phosphate cement (Harvard cement) or carboxylate cement. These have proven themselves over many decades and, depending on the material of the inlay, can be used for fixation.

Cements have high overall biocompatibility and low susceptibility to moisture at the onset of restoration.

However, depending on the material, the stability is lower than with adhesives made of plastic.

Fastening with plastic adhesive

Adhesive made of plastic is very similar in structure to the plastic used for plastic fillings. The adhesive is used together with a liquid bonding (a connector), which creates a strong bond between the tooth, adhesive and inlay.

This type of fastening is very strong and shows high stability.

Unfortunately, the plastic adhesives have many toxic and allergenic ingredients, so the biological compatibility suffers. In addition, plastic adhesives are sensitive to moisture, which must be taken very much into account when inserting the inlay.

Course of treatment in two appointments


This is the classic procedure for providing patients with inlays.

First date:

  • Removal of caries or amalgam filling
  • Tooth-friendly adaptation of the existing tooth defect for the inlay
  • Impression with hydrocolloid / silicone or digitally with an intraoral scanner
  • Temporary filling to protect the tooth

The impression is sent to the dental technician. This person produces the inlays in the dental laboratory. The fabrication takes approx. 7 days at an external dental laboratory.

Second date:

  • Temporary filling is carefully removed and the tooth defect is cleaned
  • The inlay is fixed with cement or plastic adhesive.
  • Excess cement or adhesive is thoroughly removed
  • The tooth contacts are checked and adjusted if necessary.

Course of treatment in one appointment (chairside)


The two treatment appointments can be combined on one day.

The first part of the treatment is performed in the morning. After that, the patient has a break for a few hours. During this time, the inlays can be produced in the dental laboratory.

After the break, the second part of the treatment takes place.

In this way, the inlays can be produced and inserted in one day.

Such chairside treatment can only be performed if the practice has its own dental laboratory or if with the help of CEREC.

In-house dental laboratory

In an in-house dental laboratory, the dental technician can concentrate 100% on the patients of the dental practice. As a result, laboratory-produced, high-precision inlays can be fabricated and placed in a single day.

Lab-fabricated inlays have the advantage that they can be milled with the highest precision. Thus, a 5-axis grinder with super fine 0.3mm wide cutters can produce an optimal fit and precision.

As a result, inlays have an excellent fit and the cement gap can be reduced to a minimum.

CEREC

CEREC stands for CEramic REConstruction. This is a procedure for dental practices to produce ceramic inlays quickly and easily.

Here, too, the treatment with inlays is performed in one day.

The dentist makes a digital impression with an intraoral scanner, sends the information to a small milling machine, which grinds the inlays from the ceramic blocks.

This procedure is simple and gives a good result.

However, some disadvantages become apparent. The small grinding machine has only 4-axis and the finest drills are 0.5 to 0.6mm wide. As a result, there are losses in precision and fit.

 

Cost of inlays


CEREC ceramic inlay: approx. 1000 CHF

Laboratory-made ceramic inlay: approx. 1200 – 1600 CHF

Gold inlay: approx. 2000 CHF, costs depend strongly on size and gold price

Galvanoinlays: approx. 1600 CHF

Titanium inlays: approx. 1200 CHF

FAQ on the subject of inlays


How long does an inlay last?

With a healthy bacterial flora in the mouth, the shelf life of inlays can be 15 to 30 years. In our practice, we can always keep the oral bacterial flora within a healthy range.

Does it hurt to get an inlay?

Many patients do not require an injection and find the treatment to be less painful. However, local anesthesia may be necessary.

Do I need a local anesthetic?

It depends very much on one’s own perception of pain. You may require a local anesthetic.

How long does it take for cement or adhesive to harden completely?

As a rule, the cements and adhesives require approx. 24 hours to cure completely. However, during this time you can eat normally.

How should inlays be cared for?

Shelf life is very dependent on a healthy oral bacterial flora. This can be permanently optimized and stabilized in practice.

Can inlays break?

Depending on the material, inlays can break. This is particularly the case with ceramic inlays that are too thin. However, with a correct procedure, it happens very rarely.

Which inlay materials meet the requirements of esthetic dentistry?

Ceramics and acrylics can be used very well in esthetic dentistry. Especially the aesthetic appearance of ceramics is ideally suited for this.

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