Prosthetic crowns are a type of prosthetic restoration allowing for the reconstruction of severely damaged teeth –extensive carious cavities, numerous composite restorations. It is the most durable solution that lets our patients enjoy a beautiful smile for many years.
An aesthetic prosthetic crown is consists of two elements – the so-called base, i.e. a cap, and porcelain, which is fused onto that cap and which resembles dental tissue. The base can be made from metal (noble or common) or from special, hard porcelain.
CROWNS STEP BY STEP
DIAGNOSTICS AND THE PREPARATION OF A TREATMENT PLAN
The first appointment is devoted to consultation and performing a panoramic X-ray, which constitutes the basis for drawing up a treatment plan together with a cost estimate. It is established which teeth require dental crowns. One very important stage of diagnostics is a detailed teeth analysis, paying special attention to any previous root canal treatment, and supporting it with the use of a crown-root inlay(see: crown-root inlays).
Root canal treatment is required in case of severely damaged teeth, teeth that have been reconstructed numerous times or teeth that require substantial stripping. This is often difficult to establish during the first appointment, and in the treatment plan this stage is described as “potential” (if the tooth is painful). Following root canal treatment, the teeth need to be fitted with a crown-root inlay, because as time goes by, such teeth tend to lose flexibility and might break.
STRIPPING THE TOOTH, TAKING AN IMPRESSION, CREATING A TEMPORARY CROWN
During the second appointment, the tooth or an entire group of teeth is stripped to prepare it for the crown. While stripping, it is always necessary to leave an even layer of hard dental tissue that covers the pulp.This is achieved through shaping the stripped tooth stump to exactly imitate the original shape of the tooth, albeit in a smaller size. During tooth preparation it might turn out that it is necessary to carry out root canal treatment in order to avoid any potential complications, such asacute inflammation of the pulp, and eventually also of the periapical tissue.
A dental impression is then taken. At Villa Nova Dental Clinic we use top quality impression materials that are the only substances on the market characterized by unmatched precision of the reproduction of the tiniest detail in the impression.
Based on such detailed impressions, the prosthetic lab can create a perfectly fitting prosthetic (crown, bridge, veneer) characterized by the highest possible marginal tightness.
After preparing the tooth for fitting a crown and taking the impression, another very important stage of the process is fitting the tooth stump with a temporary crown. A temporary crown performs multiple important functions, but most importantly it protects the stripped tooth from irritating external factors, such as heat or cold etc.It also protects the patient and improves their appearance while they are waiting for the final crown.
FITTING AND CEMENTING THE FINAL CROWN
The last appointment is devoted to fitting and cementing the final crown. In case of highly complicated and aesthetic reconstructions, fitting is performed during a separate appointment, but the crown is most often prepared properly and can be cemented onto the tooth without the need for any corrections.
High aesthetic expectations set for prosthetic restorations led to a number of studies focused on finding a prosthetic solution that will best imitate the natural tooth enamel. Currently all-ceramic restorations are considered one of the best. The high standard of restoration is achieved thanks to the use of computers at every stage of design and production. Thanks to this, the prosthetic restoration has the same characteristics as a natural tooth.
The main feature that distinguishes an all-ceramic crown from a classical porcelain crown on metal is the presence of a ceramic root that replaces the metal one and closely resembles the natural structure of the tooth.
1. HIGH AESTHETICS
All-ceramic restorations revolutionised the opportunities for obtaining crowns of high aesthetic value. A natural tooth is transparent enough for the light to penetrate through its entire thickness. A similar effect is achieved with all-ceramic restoration, which provides sophisticated aesthetic effects that imitate natural teeth.
In case of all-ceramic restorations and in contrast to porcelain crowns on metal, we can also avoid the blue gum effect around the neck of the tooth.
In the oral environment, metal alloys used in prosthetic restorations may undergo corrosion and can demonstrate toxicity. Corrosion is caused mainly by common metals ions.
The reaction to ions is manifested by allergy symptoms. Typically, local symptoms dominate, such as for example gum reddening. The reason for this are the ions penetrating the surrounding soft tissues. In case of all-ceramic restoration this phenomenon is absent, as Cercon is completely neutral to body tissues.
3. PRECISION, ACCURACY AND ARTISTRY
The ideal adhesion of the internal part of the crown to dental hard tissues is obtained thanks to using a computer at every stage of the creation of the crowns – CAD/CAM.
CAD, i.e. Computer Aided Design refers to the use of a computer at every stage of the design process, while CAM (Computer Aided Manufacturing) supports the manufacturing process. Thanks to the use of CAD/CAM, as well as the use of cercon oxide, we obtain prosthetic restorations of the highest quality.
The CAD/CAM technology, which is used in the manufacturing process enables to achieve perfect crown impermeability. Crown design is visible on the screen ,which allows for multiple zooming that takes care of the finest details of the crown. Computer-manufactured prosthetic reconstructions are characterised by high precision, and thus very good adhesion, which exceeds restorations produced using traditional methods. The entire process is completed with the use of a computer and design software, which eliminates many potential human errors.
The main advantages of all-ceramic crowns include:
- Stunning aesthetic effects;
- Natural transparency;
- Very high resistance and durability;
- Perfect adjustment;
- No tissue irritation or allergy.
They are used primarily to restore front teeth, as this material (zirconium dioxide) performs very well in areas of great aesthetic significance. Thanks to its physical properties zirconium dioxide enables to reconstruct not only single teeth, but also groups of teeth in the form of bridges (even very extensive), connectors or crown-root inlays used in the reconstruction of dead, endodontically treated teeth.
PORCELAIN CROWNS FUSED TO COMMON METAL
Such crowns are a last resort solution for aesthetic teeth reconstruction.
- they very often react with bodily fluids and surrounding tissues, causing allergy, with symptoms such as softening and reddening gums,
- after a few years, there is a risk that crown margins might appear, which results in the occurrence of unaesthetic grey discoloration on the gum edge,
- the metal cup blocks light, which makes such crowns look unnatural,
- the lack of possibility of achieving the high level of aesthetics afforded by all-ceramic crowns.
On account of the above reasons, we recommend all-ceramic crowns or crowns fused on gold to each patient who expects the highest standard of reconstruction. The main advantage of crowns fused on gold are their bacteriostatic properties, which prevent the development of secondary caries around the reconstructions.