Los Gatos Tooth Fillings

What is a filling exactly?

The term filling is used to describe a type of dental restoration which is placed directly into a tooth. In other words, the materials used for San Jose tooth fillings (silver amalgam, white composite) are placed directly into the teeth when soft, and harden after placement. Since fillings are placed in a single step, they are referred to as a "direct-placement" restoration. The other types of tooth restorations which are placed into teeth are referred to as "indirect-placement" restorations. These are dental crowns (caps), inlays and onlays. Indirect-placement restorations are made outside of the patient's mouth, in a dental laboratory or by a computerized mill, and are then cemented into the patients tooth.

The difference between a filling and indirect restorations is the material out of which they are made. The materials which fillings are made of can easily be placed in a tooth and harden up quickly with no ill effects to the tooth. Fillings are relatively easy and quick to place, and are a good choice for teeth in need of a small restoration, but are nowhere near as strong as an indirect-placement restoration. Crowns, inlays and onlays are made of gold and/or porcelain which both require extremely high temperatures to melt and shape which is why they are made on precise models of your teeth and not in your mouth. Gold and porcelain restorations are many times stronger and more durable than fillings, which is why they are the ideal choice for teeth which are in need of larger restorations.

What are fillings made of?

In the past, fillings were made of a mixture of liquid mercury, silver powder, and small amounts of powdered tin, copper,zinc and nickel in a 50/50 ratio of liquid mercury to powdered metals. When the liquid mercury is mixed with the powdered metals, it forms a compound known as an amalgam. The amalgam mixture is placed into the tooth and hardens up in a few minutes, although the amalgam does not fully harden for about 24 hours. Amalgam fillings come in only one color- silver. Amalgam fillings have minimum width and depth requirements to avoid fracture, so even small cavities end up with large amalgam fillings. It can be difficult to detect early cavities around the edges of an amalgam filling because of their dark color. Amalgam fillings also have a high mercury content which many medical researchers have linked to multiple health risks.

In our office, we place composite resin fillings instead of amalgam. Composite resin is a type of reinforced acrylic which is manufactured in different shades to match teeth of different color. Composite resin is placed into your tooth as a thick paste which can be shaped and sculpted as needed. When we are done shaping the composite resin a bright blue light is directed at it which causes the composite resin to turn hard. Composite resin fillings are fully hardened after the blue light has been placed on them. Unlike amalgam fillings, composite resin fillings do not have minimum size requirements, and it is easy to detect early cavities on the edges of the filling because the cavity is easily seen against a white background. Composite resin fillings are mercury free and have not been attributed to any deleterious medical effects.

Another advantage composite resin fillings have over amalgam fillings is that they can be bonded to your tooth. Bonding is a relatively new (about 20 years old now) technique in dentistry which allows a dentist to chemically glue the composite resin filling into your tooth which prevents bacteria and decay from getting under your filling. Bonding also helps to strengthen a tooth which has been filled since the bonded San Jose tooth filling adds a lot of internal support to a tooth. Amalgam fillings are not bonded, so they are much more prone to leakage and decay. Teeth with amalgam fillings are also much more prone to breaking because the amalgam does nothing to hold the tooth together. As an example, if you took a glass and filled it up with amalgam and let it set, the glass could break quite easily because the amalgam is not bonded to the glass, and could be removed fairly easily. If the same glass was filled with composite resin which was bonded to the entire internal surface of the glass, the glass would be very difficult to break because the glass and the composite resin would practically become one. Even if the glass were to fracture, it would stay together because of the bonding.

Why can't I have a filling instead of a crown, inlay or onlay?

Many patients ask this question when presented a treatment plan which includes crowns, inlays or onlays. As we discussed earlier, fillings are not as durable as a porcelain or gold restoration. By durable, we are referring to the hardness of the composite resin material. Compared to your natural teeth, composite resin is fairly soft and wears out after 5 to 10 years of normal chewing. People who grind or clench their teeth can wear through the composite resin even quicker. If the composite resin filling is fairly small and is in an area of the tooth which does not have a lot of contact with the opposing tooth (like a deep groove, on the side or at the gum line), it should last a long time. If a composite resin filling is placed in an area where there is a lot of contact with the opposing tooth, it will wear down quickly because of the difference in hardness between the tooth and the filling. Gold and porcelain restorations solve this problem because they are specifically formulated to match the hardness of your natural teeth, and they are bonded to teeth the same way composite resin is. We do not yet have a direct-placement composite resin material which is as hard and durable as gold or porcelain. Teeth get weaker as more tooth structure is removed, and teeth with large holes in them are prone to breaking. This is another reason why we choose to place a porcelain inlay, onlay or a crown. Placing a filling in a tooth which should be restored with a stronger restoration is not a beneficial service because the tooth will break at some point, requiring additional treatment; possibly a root canal or extraction.

Classification of fillings:

Fillings are classified by how many surfaces of the tooth they involve. Teeth have five surfaces- the chewing surface, cheek side, tongue side and the front and back sides where dental floss is used. The simplest filling is a one-surface filling and is used when a tooth has a cavity on the chewing surface. If the cavity is in between teeth, or extends to the cheek or tongue side of the tooth, a two or three surface filling may be required. As a general rule, if a the width of a composite resin filling will be more than one-third the width of the tooth, or if more than two surfaces are involved, a porcelain restoration is a better choice. Composite resin fillings are an excellent restorations when used in the right situations, but are not the always the best choice. In our practice we take pictures of your teeth and existing dental work using a small camera that goes inside your mouth to help you make the right decision when it comes to restoring your teeth.

How are our Los Gatos tooth fillings placed?

Having a filling placed is an simple procedure which is usually completed in 45 minutes or less. In our office, a rubber dam is used when placing fillings. A rubber dam is a thin rubber sheet with holes in it which is placed over the teeth which we want to isolate. The rubber dam does several things. When we are removing old amalgam fillings, it prevents the mercury and metal particles from going down your throat and being ingested. The rubber dam also keeps saliva and other fluids out of the tooth we are working on. Composite resin fillings are very sensitive to moisture when being placed, so it is very important to maintain a dry working field when placing them. Moisture contamination during the placement of composite resin fillings can interfere with the bonding process, which can cause post-operative sensitivity and/or subsequent failure of the restoration. Not using a rubber dam during the placement of a composite resin filling is the number one reason for failure or problems with these restorations. Some people who have never had a rubber dam placed in their mouth find it a little strange at first, but almost everyone warms up to it quickly because they like the way it prevents water and other things from going down the throat.

After numbing the tooth (if necessary), Los Gatos dentists remove the decay or old filling using either the dental drill, air abrasion, or the laser. When we are ready to fill the tooth, we treat the surface of the tooth with a series of conditioners and adhesives prior to placing the composite resin in the hole. After curing the composite with the light, the bite is adjusted and then the filling is polished. If you have any questions about composite resin fillings, feel free to come in and talk to Dr. Sawyer or Dr. Diercks at their Los Gatos dental office. Call us anytime at 408-215-1006 for dental care.