Dentists now have more options for creating pleasing, natural-looking smiles thanks to advancements in modern dental materials and techniques. Dental researchers continue to refine materials that look and behave more and more like natural teeth, such as ceramics and polymer compounds. This presents dentists and patients with plenty of options for repairing missing, worn, damaged, or decayed teeth.
However, these new dental materials have not rendered more traditional restorations totally obsolete. Materials such as gold, base metal alloys, and dental amalgam still have applications in certain situations, such as fillings for molars in the back of the mouth where chewing forces are the greatest.
The performance, durability, longevity, and cost of dental restorations are all influenced by a variety of factors. These factors include the patient's oral and general health, the filling material's composition, the placement of the filling, the chewing forces that particular tooth will have to withstand, and the total time in the dentist's chair needed to prepare and adjust the restored tooth.
With so many options, how do you know which one is best for you? Here are the benefits and drawbacks of commonly used dental restorations to help you better understand what's available.
The patient, in consultation with the dentist, should make the final decision about what to use. Discuss your options with your dentist before beginning treatment.
Dental restorations are classified into two types: direct and indirect.
Fillings that are placed directly into a prepared cavity in a single visit are known as direct restorations. During that appointment, the dentist will prep the tooth, place the filling, and adjust it for shape, polish, and bite. Restoration materials may include dental amalgam, glass ionomers, resin ionomers, and some resin composite fillings.
In most cases, indirect restorations necessitate two or more visits. Inlays, onlays, veneers, crowns and bridges made of gold, base metal alloys, ceramics, or composites are examples. During the initial visit, the dentist prepares the tooth and takes an impression of the area to be restored. The impression is passed along to a dental laboratory, where the dental restoration is created. At the follow-up appointment, the dentist cements the restoration into the prepared cavity and makes any necessary adjustments.
Composite fillings are made by combining glass or quartz filler with a resin medium to create a tooth-colored filling. They are also known as composites or filled resins. Composite fillings offer good durability and fracture resistance in small-to-medium-sized restorations that must withstand moderate chewing pressure. When the dentist prepares the tooth, less tooth structure is removed, which may result in a smaller filling than an amalgam.
Composites can also be "bonded," or adhesively held in a cavity, allowing the dentist to repair the tooth in a more conservative manner. It usually takes longer to place a composite filling than it does to place an amalgam filling. Composite fillings cannot be used unless the cavity can be kept clean and dry during the filling process, and they can stain and discolor over time.
Glass ionomers are tooth-colored, translucent materials constructed from a blend of acrylic acids and fine glass powders, particularly useful in filling cavities on the root surfaces of teeth. Glass ionomers can release a trace amount of fluoride, which may be beneficial for patients who are predisposed to tooth decay. Preparation for a glass ionomer filling requires the removal of less tooth structure, resulting in a smaller filling than with amalgam.
Glass ionomers are predominantly only used in areas that demand lighter chewing pressure. Glass ionomers are mostly used in small non-load bearing fillings (those between the teeth) or on the roots of teeth due to their low fracture resistance.
Resin ionomers are also created by combining glass filler, acrylic acids, and acrylic resin. They are also used for very small, non-load bearing fillings (between the teeth), as well as on the root surfaces of teeth, and have low to moderate fracture resistance.
When ionomers are placed on chewing surfaces, they wear out quickly. Glass and resin ionomers both mimic natural tooth color but lack enamel's natural translucency. Both types are well-tolerated and only very rarely trigger an allergic reaction.
When there are extensive damages to the tooth structure, lab-made indirect restorations are often the best solution. These two- or three-visit custom-made restorations can be a crown, an inlay, or an onlay.
In general, the cost of indirect restorations is higher because they require multiple longer visits and must be fabricated in a dental laboratory. Porcelain (ceramic), porcelain fused to a metal-supporting structure, gold alloys, or base metal alloys are used to create these restorations.
Porcelain, ceramic, or glass-like fillings and crowns are examples of all-porcelain (ceramic) dental materials. They're used for inlays, onlays, crowns, and cosmetic veneers. A veneer is a very thin porcelain shell that can replace or cover a portion of the tooth's enamel. All-porcelain (ceramic) restorations are especially appealing because their color and translucency closely resemble natural tooth enamel.
All-porcelain restorations necessitate at least two visits. These restorations are susceptible to fracture under tension or upon impact. The strength of this type of restoration is contingent on the thickness of the porcelain and its adherence to the underlying tooth. They are highly resistant to wear, but if the porcelain surface becomes rough, it can grate on opposing teeth.
Another type of restoration is porcelain-fused-to-metal, which gives a crown or bridge extra strength. These restorations are extremely sturdy and long-lasting.
By bonding the porcelain to a metal supporting structure, we can produce a more durable restoration than we could with porcelain alone. However, to properly accommodate the restoration, more of the existing tooth must be removed. Although porcelain restorations are highly wear-resistant, if the porcelain becomes rough, it can abrade opposing natural teeth. Hot and cold may cause some discomfort at first. While porcelain-fused-to-metal restorations are highly biocompatible, some patients may develop allergic reactions to the metals used in the restoration.
Gold alloys are produced by melding gold with copper and other metals, resulting in a strong, effective material for fillings, crowns, or bridges. Inlays, onlays, crowns, and fixed bridges are the most common applications. They are highly corrosion and tarnishing resistant.
Gold alloys are tough and strong, seldom succumbing to fracture and wear. This allows the dentist to remove a minimum of healthy tooth structure when preparing the tooth for the restoration. Patients tolerate gold alloys well because they are gentle on opposing teeth. Their color, however, does not resemble natural teeth.
Dental composites can be used to create crowns, inlays, and onlays in the lab. These materials are tooth-colored and similar to those used in direct fillings. Aside from aesthetics, they have the mechanical advantage of not wearing down opposing teeth excessively. Their strength and durability are inferior to porcelain or metal restorations, and they are more susceptible to wear and discoloration.
Dental amalgam has been used by dentists for over a century and is the most thoroughly researched and tested restorative material available. It is long-lasting, user-friendly, wear-resistant, and relatively inexpensive versus other materials. For these reasons, it continues to be a popular treatment option among dentists and their patients.
Dental amalgam is a stable alloy composed of elemental mercury, silver, tin, copper, and trace amounts of other metals. Although dental amalgam is still a safe and widely used restorative material, some people are concerned about its mercury content. The mercury is stabilized by the other metals in the amalgam, making it safe for use in tooth fillings.
Amalgam's safety, reliability, and efficacy as a restorative material has been confirmed by major U.S. and international scientific and health authorities such as the National Institutes of Health, the U.S. Public Health Service, the Centers for Disease Control and Prevention, the Food and Drug Administration, and the World Health Organization.
Because amalgam fillings can withstand extremely high chewing loads, they are especially useful for restoring molars in the back of the mouth, where chewing loads are highest. They are also useful in areas where it is difficult to keep a cavity preparation dry during the filling replacement process, such as deep fillings below the gum line. Amalgam fillings, like other filling materials, are formulated for biocompatibility.
One disadvantage of amalgam is that it may cause temporary sensitivity to hot or cold after the filling is placed. Another is that the silver-colored filling does not appear as natural as a tooth-colored filling, and is much more noticeable when placed near the front of the mouth, often visible when the patient laughs or speaks.
Why would a filling still in place need replacement?
Dental fillings (restorations) are subject to constant pressure from chewing, grinding, and clenching — the cumulative stress of these activities can cause them to wear, chip, and crack. Even though the wear may not be apparent to you, your dentist will easily be able to tell when a restoration is starting to degrade during a regular check-up.
When the seal between the tooth enamel and the restoration is compromised, food particles and microbes can infiltrate deeper into the tooth, accelerating tooth decay. If that decay progresses to the dental pulp, a serious infection called an abscess may occur.
In cases where decay is too significant to support a filling, your dentist may need to replace the damaged tooth with a crown.
Can I get a filling that matches the color of my teeth?
Are dental amalgams safe?