Dental Crowns

A dental crown covers the whole of a tooth above the gum. Unlike a veneer, which is bonded to the front surface, a crown encapsulates the tooth and holds on mechanically: the tooth is shaped so the crown grips it, and the crown is cemented in place. It is the classic way to give a broken-down tooth its shape and strength back.

What a crown grips matters more than the crown. The single most important factor is the ferrule: a collar of sound tooth above the gum, ideally about 1 mm thick and 2 mm high, all the way around. The crown hugs this collar like the metal band on a wooden tool handle, and it is what stops the tooth splitting. Where a tooth has broken to the gum line, that collar can sometimes be created first, by orthodontic extrusion or crown lengthening.

Bonding needs sound, healthy dentin and a dry field. A cemented crown, sometimes on a cast post and core, is the right choice when:

Very little tooth is left. A cast post and core may be the only way to hold a crown.

The dentin is poor. Old, sclerotic or heavily restored dentin does not bond reliably.

Margins are deep under the gum. If the area cannot be kept dry, a cemented crown is more predictable, sometimes after crown lengthening.

Decay risk is high. Gold's precise fit and seal make it a strong choice.

Access or isolation is difficult, or the bite is extreme.

A post does not strengthen a tooth. Its only job is to hold the core that retains the crown; when one is needed, it is because too little tooth remains to do that job.

Cast gold has served dentistry for over a century. It is kind to the opposing teeth, seals superbly, and does not depend on bonding. Its drawback is colour, which is why many patients no longer ask for it. On back teeth, and particularly second molars that take the heaviest loads, it remains an outstanding choice.

The record is long. In one specialist practice, 73% of 2,071 gold inlays were still in place after 25 years; 1,314 cast gold restorations from Dr. Richard Tucker's Seattle practice had been in service for up to 52 years; and in a randomised trial, 69% of gold partial crowns and 53% of ceramic ones were still in place at 20 years, a difference that was not significant.

Ceramic is the choice where the crown will be seen. Layered by a master technician on a core that hides what is underneath, it reads as tooth in every light; the two front teeth above are the proof. Both materials can break, and what matters is how. Porcelain is stronger and keeps its polish, but it is stiffer, so in extreme overload a fracture can take tooth with it. Composite acts as a shock absorber and is easy to repair, but wears and stains more over time.

Planning first. Dr. Reshad assesses what is left of the tooth, the bite it will meet and what you want the result to look like, and shows you the projected result before anything is touched. The tooth is then shaped for the crown, and an impression or scan taken. A crown preparation removes more tooth than any bonded restoration, which is exactly why the choice between them is made before the drill is picked up.

Fabrication. The crown is built to your tooth's shade and shape, with CAD/CAM precision and a master technician's layering, so it looks like a tooth rather than a cap.

Placement. The finished crown is tried in, adjusted to the bite and cemented. You leave with full use of the tooth the same day; some sensitivity to hot and cold can follow and usually settles within a week.

The bite is the most destructive force a restoration will face. Beautiful work that is not protected from it will not stay beautiful. Managing the bite, and fitting a night guard where there is grinding, is what keeps a result looking and working as it did on the day it was placed.