Ceramic Crowns And Bridges
What is a dental crown?
The dental crown is actually the visible part of a natural tooth that protrudes into the oral cavity. However, when one speaks of a "crown", one often means the crowning of a tooth: The tooth is ground down (prepared) by the dentist and an impression of the tooth stump is taken. In the dental laboratory, a tooth-shaped coating that fits exactly to the tooth stump is then produced, which completely surrounds and encloses the ground natural tooth. This coating restores the original shape of the tooth and can be precisely matched to the neighboring teeth in terms of shape and color. The dentist checks the fit and aesthetics of the crown and finally cements it on the tooth stump.
When do you need a dental crown?
A crown is always indicated when a tooth is significantly weakened and reconstruction with a filling, inlay or veneer is no longer an option. This is particularly the case when
- the defect (e.g. caries or old filling) extends below the gums
- the tooth is pulp dead (root-treated), this applies above all to the heavily loaded side teeth (premolars and molars)
- the tooth is deeply broken (fractured).
- Tooth decay or old fillings spread extensively around the tooth.
Ground tooth stump and crown on an incisor
However, a crown can also be necessary for aesthetic reasons if one or more teeth are badly discolored, chipped or worn and a conservative treatment with fillings no longer seems sensible in the long term. Excellent and long-lasting aesthetic results can be achieved with the all-ceramic technologies available today. For smaller defects limited to the outer surface of the tooth, however, we prefer treatment with ceramic veneers (veneers), which enable a much more tooth-friendly preparation, since only the front of the tooth needs to be slightly ground.
Case study all-ceramic crowns
Total aesthetic and functional rehabilitation with all-ceramic crowns: This 52-year-old patient wanted a total restoration because she was no longer satisfied with the aesthetic appearance of her teeth. Numerous old fillings, crowns and inlays had to be removed. The patient felt that her partially chipped and discolored incisors were extremely unsatisfactory from a cosmetic point of view. After a thorough examination and planning, we decided to restore all teeth with all-ceramic crowns, only the lower incisors received a minimally invasive treatment with ceramic veneers, as there was still enough healthy tooth substance. The entire work was carried out in a very light tooth color in accordance with the patient's wishes (above before, below after the treatment). More image examples can be found below.
There are three types of crowns or bridges depending on the material
- All-cast metal crowns: These crowns, made entirely of gold or alloys, are rarely used today for aesthetic reasons (metal visible).
- Metal ceramic crown, also called VMK crown (veneered metal ceramic crown). Here, a metal core is clad (faced) with ceramic on the outside.
- All-ceramic crowns without a metal core are the standard treatment today. The ceramic is translucent and allows a good adaptation to the natural tooth color.
Top left: full cast gold alloy crown Top right: metal ceramic crowns (VMK crowns) Bottom: full ceramic crown and bridge
Metal-free all-ceramic crowns
Today it is possible to produce completely metal-free ceramic crowns and bridges that can withstand the chewing pressure in every way. It is also no longer necessary to grind down the tooth more than usual for ceramic crowns. The keyword for this progress is zirconium: ceramic frameworks made of zirconium dioxide (ZrO2), also known as zirconium, have extreme mechanical strength values and can compete with the hardest metals. The white zirconia framework is milled out of a zirconia block using computer-controlled CAD/CAM milling machines and then individually veneered with tooth-colored porcelain. In addition to zirconia, lithium disilicate ceramic (Emax) can also be used for single crowns.
Left: Zirconium bridge framework. Right: Finished veneered work with color sample
48-year patent: incisors before and after treatment with all-ceramic crowns, at the same time aesthetic harmonization of the gum line
All-ceramic crowns are characterized by outstanding aesthetics, since the light is not only reflected, but also, like natural teeth, there is real transparency (showing through). This effect qualifies the porcelain crown particularly for the front tooth area, whereby minor shape and position corrections are also possible.
Translucency (light transmission) of an all-ceramic crown (left) and a VMK metal-ceramic crown (right) compared when illuminated with a light source
Another advantage of the metal-free construction is the tooth-colored crown edge, which does not necessarily have to be placed under the gums. As a result, there is no gum irritation or recession caused by the crown edge.
Ceramic (porcelain) is an extremely biocompatible material that has no allergenic potential, i.e. does not cause allergies. This can be a real benefit for allergy sufferers.
Case studies from our practice
Aesthetic and biocompatible amalgam restoration with metal-free ceramic crowns
This 39-year-old patient contacted us with a request for a total rehabilitation. All teeth were severely affected by caries, wear and tear and defective fillings and the bite had dropped (deep bite). A lasting restoration could only be achieved by crowning all teeth. In order to make the sometimes long treatment sessions less stressful for the patient, we carried them out with additional nitrous oxide sedation, which the patient found extremely pleasant. After the aesthetic and functional rehabilitation with 28 all-ceramic crowns, the original bite height is restored (bite elevation).
Left: Zirconium bridge framework. Right: Finished veneered work with color sample
What is a pen crown?
A post tooth or post crown is a crown that is anchored with a root post in the root canal of the tooth. This may be necessary to rebuild badly damaged and root-treated teeth. In the case of pivot teeth, the root post, abutment and crown used to be made in one piece. Today, a post made of ceramic, plastic or metal is cemented in the root canal and fitted with a plastic structure. The impression for the crown is then taken and this is cemented to the abutment.
What is a dental bridge?
A dental bridge is a fixed denture that is used when one or more teeth are missing and the gap is bordered by teeth on both sides. To make the bridge, the neighboring teeth are ground down (prepared) and an impression is taken of the tooth stumps. The bridge, consisting of two tooth crowns (pillars) and the tooth in between (pontic), is manufactured in the dental laboratory and then firmly cemented onto the tooth stumps.
In the past, the bridge was the only way to replace missing teeth with fixed dentures. Today, the gap closure is more likely to be done with an implant, since you do not have to grind down the neighboring teeth. A bridge is still used in some cases, e.g. if the neighboring teeth have to be crowned anyway.
What is an adhesive bridge or adhesive bridge?
Adhesive bridge (Maryland bridge) to replace a missing tooth. The tooth is glued to the back of the neighboring tooth with the wing
A bonded bridge, also known as a Maryland bridge or adhesive bridge, is bonded to the back of adjacent teeth with small ceramic or metal wings without the need to grind them down. In many cases, this particularly gentle method is well suited for small gaps in the front teeth or temporary restorations and can sometimes also be an alternative to implants . However, if the "interlocking" between the upper and lower jaw teeth is too tight, there is sometimes not enough space for the adhesive flap, so this solution is ruled out.