Fillings are so commonplace in the dental office that people tend to take them for granted. While it is true that there are seldom complications from this dental procedure, it is important to understand the different materials available for restorations and their benefits.
Air Abrasion Fillings
Sometimes the decay is totally within the enamel. Since bacteria are present these areas of decay must be removed. We use air abrasion to remove just the decayed part of the tooth without affecting healthy tooth structure.
Air abrasion technology is a mainstay of our office restorative procedures. We have several air abrasion instruments that we use to prepare teeth for restoration with filling material. Essentially air abrasion works as a gentle mini sand blaster, using mildly abrasive aluminum dioxide powder as the “sand.” This system is advantageous for our patients because we can use it in many cases to remove stains, bacteria, and decay from a tooth, without having to remove healthy, non-decayed structure as can be the case with a traditional dental drill.
We use this system for many different procedures. It is ideal for use in small fillings where we have easy access – the kind of decay shown often in children. We can gently clean away the decay without anesthesia and with the most conservative preparation to preserve healthy tooth. We also use this system as a final step in larger fillings before placing the filling material because its “sand basting” action helps provide a better surface for enhancing the bond strength (“gluing” of filling material to tooth) of composite resin restoration.
Types of Fillings
These are tooth colored fillings that are bonded in place. The filling material is composed of quartz ceramic particles in a matrix of liquid resin; the material is hardened, or cured, by a special light. These fillings harden quickly (silver fillings take about twenty-four hours to harden) and a patient can chew on them immediately after placement. We use composite materials for most fillings we place.
A tooth is prepared for a composite filling with either a drill or air abrasion technology. The tooth is then etched with a gentle acid (about the strength of lemon juice) to make it rough to accept a bond, and a bonding agent is placed on the tooth. The filling material is then placed and cured with a light. After the filling material is placed and sculpted, occlusal (bite) adjustment is performed.
Advantages: Tooth colored fillings look good, and since the filling material is chemically bonded to the tooth, this type of filling material resists fracture. Composite fillings can also be kept smaller than silver fillings because no undercuts are necessary for retention of the material, and air abrasion technology can be used in tooth preparation in many cases where composites are used.
Disadvantages: This type of filling is very technique sensitive. If a drop of saliva leaks into the prepped filling area, the bond may not take and the filling may have to be replaced. This occurs in about 0.5% of composite fillings placed. Since the filling is hardened before anesthesia wears off, there may be a higher incidence of needing a filling adjustment with this type of filling. Adjustment is required about 1% of the time.
Silver Amalgam Fillings
Amalgam is the traditional filling material that has been the basic restoration material in dentistry. To place a silver filling, decay is removed with a drill, and undercuts are made into the tooth to lock the metal in place. Amalgam is placed in the tooth, packed, and carved. The filling remains soft for twenty-four hours, so care must be taken with chewing for a while.
Silver amalgam is composed of silver mixed with other metals such as copper, with mercury added to keep the material soft while working it.
Advantages: This material is easy to work, inexpensive, and durable. Silver amalgam can be placed in a wet environment; saliva does not affect a silver filling’s success to the same degree.
Disadvantages: Amalgam does not look natural and cannot be used where a filling is visible while smiling. The need to make undercuts destroys sound tooth structure, although it is possible to use a special bonding agent with amalgam that minimizes the need for undercuts. Silver amalgam fillings do not provide support for the rest of the tooth and are more subject to fracture of the natural tooth structure than a bonded composite resin filling.
Current research contends the mercury in silver amalgam has not been proven to cause any side effects except in persons with specific metal allergies. However, it is known that after placement of a silver filling, there is a rise in mercury level in that person for a period of time. There has been no proven correlation between this and any adverse health effects to the date of publication of this article.
Complications of Fillings
Occasionally a filling needs to be adjusted because the occlusion is off. This usually happens because it can be difficult for a patient to feel a proper adjustment when he or she is numb from anesthesia. A quick visit to the office is usually all that is necessary to adjust a filling. This complication occurs in about 1% of fillings.
A filling may be sensitive because it is "high" and needs adjustment, because it was a deep restoration, or because a bond may not have been successful. We ask that patients call the office if sensitivity persists beyond two days.
If a filling was very deep and near the pulp, there is a chance that the tooth could abscess and need a root canal. This is because bacteria can damage the pulp without showing up as actual decay. If a patient has a filling that is close to the nerve, we will inform that there may be a future need for a root canal. Occasionally because of unusual tooth anatomy, a filling that is not that deep can nick pulpal projections called pulp horns, and there may be no way of predicting the need for a root canal in the future.
Rarely a person may have an allergy to a dental material used in filling placement, including metals, latex, bonding agents, or adhesives. We ask patients to let us know of any known allergies.