Indirect Composites

Crowns, inlays and onlays can be made in the laboratory from dental composites. These materials are similar to those used in direct fillings and are tooth colored. one advantage to indirect composites is that they do not excessively wear opposing teeth. Their strength and durability is not as high as porcelain or metal restorations and they are more prone to wear and discoloration.

Base Metal Alloys

Base metal alloys are non-noble metals with a silver appearance. They are used in crowns, fixed bridges and partial dentures. They are highly resistant to corrosion and tarnishing. They also have high strength and toughness and are very resistant to fracture and wear.

Some patients may show allergic sensitivity to base metals and there may be some initial discomfort from hot and cold. The metal color does not mimic natural teeth.

Gold Alloys

Gold alloys contain gold, copper and other metals that result in a strong, effective filling, crown or a bridge. They are primarily used for inlays, onlays, crowns and fixed bridges. They are highly resistant to corrosion and tarnishing.

Gold alloys exhibit high strength and toughness that resists fracture and wear. This allows the dentist to remove the least amount of healthy tooth structure when preparing the tooth for the restoration. Gold alloys are also gentle to opposing teeth and are well tolerated by patients. However, their metal colors do not mimic natural teeth.

Indirect Restorative Dental Materials

Sometimes the best dental treatment for a tooth is to use a restoration that is made in a laboratory from a mold. These custom-made restorations, which require two or more visits, can be crowns, inlays or o­nlays. A crown covers the entire chewing surface and sides of the tooth. An inlay is smaller and fits within the contours of the tooth. An o­nlay is similar to an inlay, but it is larger and covers some or all chewing surfaces of the tooth. The cost of indirect restorations is generally higher due to the number and length of visits required, and the additional cost of having the restoration made in a dental laboratory. Materials used to fabricate these restorations are porcelain (ceramic), porcelain fused to metal, gold alloys and base metal alloys.

Ionomers

Glass ionomers are tooth-colored materials made of a mixture of acrylic acids and fine glass powders that are used to fill cavities, particularly those o­n the root surfaces of teeth. Glass ionomers can release a minute amount of fluoride that may be beneficial for patients who are at high risk for decay. When the dentist prepares the tooth for a glass ionomer, less tooth structure is removed; this may result in a smaller filling than that of an amalgam.

Glass ionomers are primarily used as small fillings in areas that need not withstand heavy chewing pressure. Because they have a low resistance to fracture, glass ionomers are mostly used in small non-load bearing fillings (those between the teeth) or o­n the roots of teeth.

Resin ionomers also are made from glass filler with acrylic acids and acrylic resin. They also are used for non-load bearing fillings (between the teeth) and they have low to moderate resistance to fracture.

Ionomers experience high wear when placed o­n chewing surfaces. Both glass and resin ionomers mimic natural tooth color but lack the natural translucency of enamel. Both types are well tolerated by patients with o­nly rare occurrences of allergic response.

Composite Fillings

Composite fillings are a mixture of acrylic resin and finely ground glasslike particles that produce a tooth-colored restoration. Composite fillings provide good durability and resistance to fracture in small-to-mid size restorations that need to withstand moderate chewing pressure. Less tooth structure is removed when the dentist prepares the tooth, and this may result in a smaller filling than that of an amalgam. Composites can also be "bonded" or adhesively held in a cavity, often allowing the dentist to make a more conservative repair to the tooth.

In teeth where chewing loads are high, composite fillings are moderately resistant to wear, but less so than amalgam fillings. The cost is moderate and depends o­n the size of the filling and the technique used by the dentist to place it in the prepared tooth. The time required to place a composite filling is usually longer than what is required for an amalgam filling. Composite fillings require a cavity that can be kept clean and dry during filling and they are subject to stain and discoloration over time.