RECENTLY, after attending a meeting of the Guyana Dental Association, a colleague of mine told me he was glad that I have been writing this weekly column for the past 20 years. I was mildly surprised, and asked the reason for his view.

He replied that it gave his patients who have been reading them some knowledge of dental procedures, which then made his work much easier, since he often does not have the time to explain the details of what he was doing in their mouths.
Clearly, this dentist did not realise that this was a primary objective of my efforts over these two decades. So, while there are terms and dental procedures that patients often hear mentioned, it is not uncommon for them to not only be ignorant of what specifically they imply, but more importantly, if any of them would be required for that patient.
Let us examine crowns (also referred to as caps), which are simply dental restorations that surround that prepared tooth structure to help strengthen weakened teeth that have been cracked, broken or decayed.
Dentists also use crowns to help restore a tooth’s shape and improve chewing function, speech and aesthetics (good looks.) These crowns are made from various types of materials which get bonded or cemented into place.
Crowns can be made from porcelain (or some form of dental ceramic), metal (a gold or other high noble metal alloy), or a combination of both. Since these crowns cover the entire visible portion of the tooth, from the gum level up, they, in essence, become your tooth’s visible surface.
A crown is made in a dental laboratory from the impression that your dentist took of your prepared tooth. Your dentist prepares your tooth by first removing any old, failing restorations, and any weak or decayed areas of tooth structure. Then the core of the tooth is built up with resin-type materials that simulate the tooth structure it is replacing. Enough tooth structure is removed all around to allow for the proper thickness of metal and/or porcelain, which gets fabricated by the dental lab.
On average, it takes about one week for this restoration to be ready. Porcelain or all-ceramic crowns are very expensive, and the process to make them is complex and protracted. I generally do not recommend them. However, this material can have different shades of porcelain layered together to create a very polychromatic, natural-looking tooth with natural translucencies and characteristics that blend fairly well with teeth surrounding them.
One can say that polycarboxylate, composite resin and acrylic all have the same appearance, but are much cheaper and easier to manage, and can be repaired if damaged.
Porcelain crowns cannot be repaired; they have to be replaced altogether. On the other hand, once metal is involved, which is almost always the case with porcelain crowns, the dental lab technician would have to place a white opaque material over the metal to try and block out the dark characteristics. As a result of the metal and opaqueness, the light does not get reflected, and is absorbed.
You can still have good aesthetics with porcelain-fused-to-metal (PFM) crowns, but it may require more tooth preparation (removing more of your natural tooth) to allow for more room for the layering or the porcelain to mask what is underneath. When the patient is a grinder, or requires more strength and stability, the dentist may recommend a crown that is reinforced with metal, although there are new materials now that are very strong that do not contain any metals. The most common are Zirconia and Procera.
Finally, there are times that crowns may be fitted instead of having to go through the long, tedious and expensive process of wearing braces. What the dentist does is take an impression of your jaw with the crooked teeth. He will then contour the model, and fit crowns on it with your teeth alignment corrected. The identical thing he will then perform in your mouth, then cement on the crowns. That process could take a week instead of up to three years wearing braces.
Obviously, your dentist will first have to carefully analyse your case, craft a treatment plan, and professionally assess and decide if it will be successful.