Dental crowns past and present

There are many ways to crown! Some are better than others, but they are all so good at fixing teeth that are in critical conditions and need repair.

Traditional crowns

Traditional crowns are metal porcelain constructs. Over metalcore is an individually crafted porcelain cap that is often fully finished in a dental laboratory with a set shade, texture and translucency, which is then fitted by a dentist Soho.

In years gone by, dental teams would have had to make the top of the crown in surgery, which was a skill that was tough to master. Alternatively, a crown would need to be made in a laboratory, which also proved to be tricky due to often inaccurate dental moulds.

In situ resin crowns

In situ resin crowning is one of the techniques that has grown with the newly adopted use of UV-light-cured dental resin. They were originally introduced to the clinic as an adhesive to hold veneers in place. When it became clear that the resin could be placed down in layers – the first layer hardened before the next was applied to build much larger three-dimensional structures – it became obvious that they would have a key role in an entirely new type of oral prosthetic.

An in situ resin composite crown is fabricated in place in the patient’s mouth, thereby eliminating the use of a dental laboratory. This increases the length of the procedure but circumvents having to wait for a crown to be fabricated by a third party. The procedure usually takes place in a single session.

The work becomes solely the responsibility of the practicing dentist, with in situ crowns being highly variable in quality. The resin used at the earlier layers affects the strength of the prosthetic, with the final layers being carved and textured using a dental drill and blended into the surrounding teeth. With sufficient skill, this can be done to a very high standard.

In-clinic milling

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In-clinic milling uses automated multiaxial milling machines to fabricate polymer composite components using computer-aided design software. This is a distributed model of producing crowns; it is quite a technologically dependent process that very few clinics have invested in. Those who have invested have gained the capacity to give their patients a wide variety of services without the vulnerability that comes along with supply chains.

It works best when paired with 3D scanning technology, allowing the area that requires crowning to be digitally mapped. That map is then processed on a computer in the clinic, where the crown can be designed from the blank porcelain composite blocks and its interface precisely lined up with the specific area of the digital map of the patient’s mouth.

The resulting 3D model is sent on to the mill, which, completely independent of supervision, works away, grinding down the porcelain blanks into the desired shape. It can then be immediately taken off the mill, rinsed and bonded into the patient’s mouth, literally making crowns while you wait! It is a good mix of the precision and repeatability of laboratory fabricated crowns, along with the flexibility and customization at in situ bonding that opens the procedure up.

Apurva Thakur

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