NEWS AND DENTAL EDUCATION

Most cavities discovered during a dental examination will need to be treated. In general, if a cavity has broken through the enamel and is into the underlying dentin, or is able to be probed with an explorer, it has undergone cavitation and requires treatment. Early dental cavities that have not spread to the dentin or have undergone cavitation should not be treated, as they can be healed or re-mineralized with fluoride.

The goal of treating cavities involves two basic principals:

1. Removing the decayed portion of the tooth

2. Rebuilding the missing tooth structure with a filling material.

The dentist usually begins the procedure with an injection of local anesthetic if the decay is deep and very sensitive. A high-speed dental drill is needed to remove the decay and prepare the tooth for the filling. Depending on which material is used, the dentist will vary the tooth preparation accordingly.

After the tooth has been prepared, a liner (Dycal®)is often used to reduce tooth sensitivity.Dycal is a compound containing calcium hydroxide, and is used in deep cavities to stimulate the dentin to regenerate and protect the dental pulp. In deeper fillings, a base is used in addition to the liner. Common bases used under dental fillings are glass ionomer cement and zinc phosphate cement. The main purpose of the base is to insulate the tooth from temperature changes in the mouth. The dentist and patient can then choose a number of different materials to fill the tooth, but the most common are silver (amalgam), white (resin), porcelain or gold. These materials are layered on top of the liner or base to finish the process of rebuilding the tooth. After a tooth has been filled, it is not unusual for the tooth to be sensitive for a day or two. In general, the deeper the filling, the more likely the tooth will have prolonged sensitivity, especially to cold food or beverages. Most fillings should be completely comfortable within two weeks. In some cases, the filling will be built up too high, and a second appointment is needed to shave down the filling to a comfortable level. If sensitivity lasts more than two weeks, it may indicate that there is a void under the filling. Prolonged discomfort may also indicate a tooth that has an infected pulp, and requires root canal therapy.

Every dental material used to rebuild teeth has advantages and disadvantages. Dental amalgam or silver fillings have been around for over 150 years. Amalgam is composed of silver, tin, copper, mercury and zinc. Amalgam fillings are relatively inexpensive, durable and time-tested. On the flip side, they are considered unaesthetic because they blacken over time and can give teeth a gray appearance, and they do not strengthen the tooth. Some people worry about the potential for mercury in dental amalgam to leak out and cause a wide variety of ailments, but research does not bear this fear out. Advantages:

• Cheap
• Strong
• Lasting
• One visit

Disadvantages:

• Not aesthetic (Silver colour)
• Blacken over time and can give the teeth a gray appearance
• Contain mercury
• Required deeper cavity to retain amalgam
• No chemical bonding to tooth structure

Composite Resin/White Filling

Composite resin, or white fillings have been around for about two decades. Composite fillings are composed of an organic polymer known as bisphenol-A-glycidyl methacrylate (BIS-GMA), and inorganic particles such as quartz, borosilicate glass and lithium aluminum silicate. They have the advantage of requiring a more conservative tooth preparation (less drilling required), can have a strengthening effect on the tooth and are very aesthetic, virtually blending in with the tooth. Composite fillings are the material of choice for repairing the front teeth. On the down side, they are more technique-sensitive for the dentist to place, and are highly susceptible to decay in the future if placed improperly. They usually cost more than an amalgam. Despite this research composite fillings are considered safe, and like the other dental filling materials, they are approved by the American Dental Association. Advantages:

• Highly aesthetic – it can be used to improve aesthetic
• Can be used for shallow cavities
• Chemically bond to tooth structure
• One visit

Disadvantages:

• Technique sensitive (required dry surface for filling adhesion)
• Can result in tooth sensitivity (due to shrinkage of the composite)
• The strength of composite is lesser than amalgam
• Required replacement or repair due to staining, chipping, wear and tear
• Cost more than amalgam

More info on aesthetic filling click here

Porcelain inlay/onlay/crown

Porcelain is sometimes used for dental fillings called onlays or inlays. Porcelain is a non-crystalline glass composed of silicon and oxygen. It has the advantage of being highly aesthetic, and is the restoration of choice for people who place the highest value in the appearance of their teeth. Porcelain has the disadvantage of being brittle, and, therefore, susceptible to breakage. It is also even more technique-sensitive to use than composite; requires two dental visits to place the filling; and costs significantly more than amalgam or composite fillings. Porcelain can also cause accelerated wear of the opposing tooth when biting. Advantages:

• Highly aesthetic
• Strong
• Lasting

Disadvantages:

• Required to scarified more tooth structure for retention
• The retention of the porcelain is depends on the cement used to ‘glue’ the porcelain to the tooth
• Porcelain is brittle and susceptible to breakage
• Required two visits
• Can cause accelerated wear of the opposing tooth when biting
• Expensive

More info on crown click here

Gold Inlay

Gold is sometimes used for dental fillings, most commonly as an inlay. Gold is not used in its pure form, but as an alloy containing 75 percent gold, as well as copper, silver, platinum, palladium and zinc. Gold is extremely durable; fairly aesthetic, it does not damage the opposing tooth when biting, and is very well tolerated by the gums and other intraoral tissues. A well-done gold filling can last two to four times longer than any other dental material and might be considered the “gold standard” for dental fillings. Gold inlays, like porcelain inlays, take two dental visits to complete and are also much more costly than amalgam or composite. They are also not nearly as aesthetic as composite or porcelain. In addition, gold inlays are fairly difficult to prepare and place.