Porcelain Inlays & Crowns

The Ultimate Protection for Teeth

General Information

Crowns are a type of dental restoration which, when cemented into place, cover that portion of a tooth which lies above and at the gum line, protecting what remains of the natural tooth.  In comparison, fillings are restorations that fill in, or cover over just a portion of a tooth.

Why do teeth need dental crowns ?
A dentist might recommend the placement of a crown for a variety of reasons but, in general, most of these reasons will fall within one of the following basic categories:

  • To restore a tooth to its original shape.
  • To strengthen a tooth and protect against further breakdown and deterioration.
  • To improve the cosmetic appearance of a tooth (shape or colour).
  • To alter the bite or change the relationship/pattern of contact of teeth during chewing.
  • As an attachment to lock and stabilize a denture.

How do dental crowns strengthen teeth ?
The strengthening capability of dental crowns is related to the fact that dental crowns cup over and encase the tooth on which they are placed, thus binding the tooth together.  Dental crowns are a very important means by which a dentist can help strengthen a weak and vulnerable tooth.

In contrast, dental fillings, especially large ones, often have a weakening effect on the teeth in which they are placed.  Dental fillings largely rely on a tooth’s remaining structure to hold and support them.  Fillings, in general, don’t strengthen a tooth and they don’t protect a tooth from the forces generated by biting and chewing.

The relationship between dental crowns and root canal treatment
While both of these dental treatments may be required, they are entirely separate procedures and, most certainly not every tooth which has a crown placed on it needs root canal treatment.

Root canal therapy involves removal of the pulp tissue of the tooth, which is made up of the nerve tissue and blood vessels.  Following root canal therapy, the tooth no longer has the same blood supply and, indirectly the same water supply, making these teeth very brittle and at risk of fracturing.  Because of the extremely high forces that back teeth are subjected to during normal chewing and functioning, if a back tooth has had a root canal therapy it is important to protect the tooth with a crown.

What are the potential consequences of not protecting a tooth with a crown ?
No dentist can know precisely what set of occurrences will transpire with any particular tooth.  They are simply advising you as to what they consider to be the most predictable treatment for the long-term health of your tooth.

  • The most common outcome for an untreated tooth which is in need of the protection of a dental crown is that it will crack.  Unlike cracks in bones, cracks in teeth do not repair themselves or heal.  Once a crack has formed, it will, with time, increase in size due to the cumulative effects of repeated exposure to biting forces (which is further aggravated by the ongoing contraction and expansion of amalgam silver mercury fillings).  This can result in tooth splitting, rendering the tooth unrestorable and necessitating removal of the tooth.
  • Often a segment of tooth will fracture off – if this extends deeply below the gum line, the tooth may require referral to a gum specialist to surgically reposition the gum so that the tooth can be properly restored.
  • In many situations a crack ca progress to involve the pulp of the tooth leading to irreversible nerve damage.  Teeth like this require either removal or root canal therapy and a crown.
  • Unless a portion of your tooth has broken off, you may well be unaware of any cracks which have developed.  This is because many cracks are difficult if not impossible to visualize (very few cracks are ever visible on x-rays), and not all cracks in teeth are significant enough to produce symptoms in the early stages.

As you might expect, the amount of pain or discomfort which is associated with a tooth which has a crack can vary widely depending on the specifics and extent of the situation.
Sometimes these teeth:

  • Are totally asymptomatic.
  • Are irritatingly rough to the tongue or cheek.
  • Have an increased sensitivity to hot and cold stimuli.
  • Are painful to biting pressure.
  • Are spontaneously painful.

In cases like those described above, crowns can be used to splint teeth, protecting them from potential loss.
Crowns look and feel like natural teeth.  Depending on the circumstances of each situation crowns can be made of porcelain (highly aesthetic crowns that are indistinguishable from natural teeth)or porcelain fused to a metal substructure or metal only.

How long do crowns last ?
International research suggests that the average crown has a life span of 7 to 10 years.  However, no dentist can predict how long your natural teeth will last, let alone dentally restored teeth.  How long any restorative dentistry lasts will depend on many factors:-
  • how well teeth are maintained and looked after.
  • how well the treatment is done.
  • the unique biology of each individual’s mouth (buffering capacity and salivary flow rate etc).
  • habits such as clenching and tooth grinding, etc.

On very rare occasions crowns can fail (because of recurrent decay) or because of material failure – it is far more favourable to have some porcelain flake off a crown (which can be easily replaced), than to have the tooth itself break.

Crowns themselves cannot decay, but the underlying tooth structure can.  For this reason, it is important that restored and unrestored teeth be looked after proactively as part of an ongoing programme.  Only in this way can you be confident of optimizing the longevity of your natural and restored teeth.

In some situations, particularly where the teeth on either side of a gap are already crowned or are extensively filled,  the most appropriate choice  to replace lost teeth may be with a conventional bridge. The teeth on either side of the space are prepared for crowns that support a framework spanning the gap and replacing the lost tooth. When replacing front teeth modern high-tech all ceramic materials can be used in bridges which are strong and durable and are very natural and attractive in appearance.

What if I have more questions ?
Just ask.  Our office is well experienced in the procedure of preparing teeth for crowns and we’ll be happy to answer any questions that you may have.