As expectations rise for dental crowns to match perfectly the colour and appearance of natural teeth, special attention is paid to the materials used for crowns (especially those used for replacing front teeth), with the aim of providing the patient with a beautiful aesthetical smile.
Porcelain crowns, incorporating a metal alloy foundation, have been used for many years, but lacking the light transmittance of natural teeth, leave the patient with a slightly grey result. These metal crowns can cause a greying of the gums over time, and can also be responsible for allergic reactions. In recent years, newer, healthier and more effective materials have been discovered, giving patients a more satisfactory end result.
Consequently, the tissue-friendly material, zirconium, is now being used in dentistry. Zirconium coatings now offer a similar strength to the previously used metallic alloy used in the past.
Zirconium is translucent, does not cause discolouration of the gums, is non-allergic, and is resistant to corrosion, and has since become the first choice for dental restorations.
Providing the patient submits to regular dental controls, zirconia crowns can last for many years. Natural teeth are living tissues and may become deformed over time due to wear and infections, whereas zirconia crowns are resistant to change over time. However, changes in the mouth structure later in life may cause the zirconia crown to be adapted or replaced where necessary.
Will there be any damage to the underlying natural tooth in the event of the zirconia crown being replaced?
The patient will not feel any discomfort when the crown is removed, and there will be no loss of the natural underlying tooth tissue.
Due to the light transmittance properties of the zirconia material the crown will have the same natural appearance as the patient’s existing natural teeth. Light passes through the enamel of healthy teeth, whereas, the metallic base of conventional porcelain crowns creates an opaque, dull, and artificial look to the teeth – zirconia crowns eliminate these aesthetic problems.
A zirconia crown does not contain any metal material, thus does not cause any allergic reactions.
Do zirconia crowns cause discoloration in the future?
The polished and smooth surface of zirconia crowns does not allow for the accumulation of plaque, and neither does it allow for the discoloration caused by tea, coffee, and smoking.
Will zirconia affect the sense of taste or cause bad breath?
The use of zirconia will not cause any adverse effects to the mouth of the patient.
The surface of the patient’s natural tooth is reduced very slightly. This may cause some swelling to the surrounding gum. When the swelling has reduced, a dental impression is taken. In our in-house laboratory, a zirconia base is produced matching the color of the natural teeth. This is then given a fitting trial with the patient. Final adjustments are made, polishing takes place and the final result is permanently cemented into place. The patient can then use the zirconia crown as if it were their natural tooth.
As with the preparation for fitting a porcelain crown with a metal alloy base, the surface of the natural tooth is ground down by about 1-2 mm, with the loss of material being slightly higher than when fitting a porcelain laminate.
Is the procedure painful?
The procedure is undertaken with the use of a local anesthetic. A temporary crown, matching the patient’s own teeth color, is then attached to prevent sensitivity to cold or hot. A few patients might experience a mild tingling during the procedure, but generally, the procedure is usually completed without problems.
Are there any aesthetic problems experienced during treatment?
A temporary zirconia crown will be attached for the front teeth of a similar design to the final permanent zirconia crown. This temporary crown is made of acrylic material and not overly strong; however, the color match and shape will be very satisfactory.
Zirconia crowns may crack or break in the case of excessive or adverse force, however, the possibility of breaking or cracking is similar to the possibility of breaking a natural tooth. These problems can be cared for at our clinic. Zirconia crowns may fall out if the natural tooth supporting it beneath decays. In such cases, the tooth is treated where possible, and the crown is again cemented in place.
There is no reason not to attach a zirconia crown after the gingival disease has been adequately treated.