Dental fillings are a common procedure used to restore teeth that have been damaged due to decay. Among the many materials available, dental amalgam remains one of the most frequently used. This silver-colored filling material has been trusted by dentists for over a century. In this article, we will explore the types of dental amalgam used for fillings, their components, advantages, disadvantages, and the reasons why they are chosen over other materials.
What Is Dental Amalgam?
Dental amalgam is a material used by dentists to fill cavities caused by tooth decay. It is made by mixing a powdered alloy (primarily consisting of silver, tin, copper, and sometimes zinc) with liquid mercury. This combination forms a material that hardens inside the cavity to restore the tooth’s function and shape.
Amalgam has been widely used for over 150 years, earning the nickname “silver fillings” due to its color. Despite the rise of other materials like composite resins, dental amalgam remains a popular choice due to its durability, strength, and cost-effectiveness.
Components of Dental Amalgam
Dental amalgam consists of the following components:
Mercury: Mercury makes up about 50% of the mixture by weight. It acts as a binder that allows the alloy particles to blend together, giving the filling its smooth, moldable properties. Mercury is essential in making amalgam malleable when applied to the cavity.
Silver: Silver is the most abundant metal in the alloy. It adds strength and durability to the amalgam. Silver also contributes to the material’s resistance to corrosion, making it suitable for use in the back teeth, where heavy chewing forces are present.
Tin: Tin helps to control the setting reaction of the amalgam. It plays a role in improving the workability and setting time of the mixture. It also contributes to the alloy’s ability to resist corrosion.
Copper: Copper helps improve the material’s strength and longevity. It is often added to increase the resistance to corrosion and wear, as well as to improve the filling’s overall performance.
Zinc (Optional): Zinc is sometimes added to the alloy to improve its properties, such as enhancing its resistance to corrosion and expanding the amalgam’s longevity.
Together, these components create a durable, stable, and functional material that can withstand the pressures of chewing and biting.
Types of Dental Amalgam
Dental amalgam comes in different types, primarily based on the ratio of the metals used. The most common types include:
1. Traditional Dental Amalgam
Traditional amalgam, or high-copper amalgam, is made up of silver, tin, copper, and mercury. This amalgam has been in use for many years and is known for its strength and durability. The higher copper content in these types of amalgams helps prevent corrosion and the formation of harmful corrosion products, making it a more stable material.
2. High-Copper Amalgam
High-copper amalgams are an upgraded version of traditional amalgam. They have a higher percentage of copper (typically 12-30%) compared to traditional amalgam, making them more resistant to corrosion and wear. This type of amalgam is now preferred by many dentists because it has a better clinical performance and lasts longer than traditional amalgam.
3. Admixed Amalgam
Admixed amalgam is a blend of traditional low-copper amalgam with high-copper amalgam. The idea behind this mixture is to combine the best qualities of both types. Admixed amalgam tends to have better handling properties, strength, and resistance to corrosion compared to low-copper amalgams, while still maintaining a reasonable cost.
4. Spherical Amalgam
Spherical amalgam is made up of small, round particles rather than the irregularly shaped particles in traditional amalgams.
This type of amalgam allows for easier handling and less wastage, and it often sets faster. Spherical amalgam is popular in areas of the mouth where a more fluid mixture is needed, such as when filling the back teeth.
Advantages of Using Dental Amalgam
Dental amalgam has several key advantages, which is why it remains widely used for fillings:
1. Durability and Longevity
One of the most significant benefits of dental amalgam is its exceptional durability. Amalgam fillings can last anywhere from 10 to 15 years or even longer with proper care. This longevity makes them a cost-effective option, as they don’t need to be replaced as frequently as other materials, such as composite fillings.
2. Strength and Resistance to Wear
Dental amalgam is extremely strong and able to withstand the significant chewing forces that occur in the back teeth. This strength is essential for fillings that are placed in areas that experience heavy biting and grinding forces, such as molars.
3. Cost-Effectiveness
Amalgam is more affordable than other filling materials, such as composite resins or gold fillings. Its cost-effectiveness makes it a good choice for patients who need multiple fillings or are looking for a budget-friendly option.
4. Ease of Placement
Dental amalgam is easy to manipulate and mold into the cavity, making it a versatile material for filling different types of cavities. It also requires less moisture control during placement, which can be a challenge with other materials like composite resins.
5. No Need for Tooth Removal
Unlike some other filling materials, amalgam requires minimal removal of the natural tooth structure. The dentist only needs to clean out the decayed part of the tooth, preserving as much healthy tooth as possible.
6. Resistance to Leakage
Amalgam has a low risk of leakage over time, as it expands slightly after placement, helping to seal the edges of the filling.
This reduces the risk of bacteria and decay re-entering the tooth.
Disadvantages of Dental Amalgam
While dental amalgam has many benefits, there are also a few disadvantages that should be considered:
1. Aesthetics
Amalgam’s silver-gray color can be noticeable, especially when placed in the front teeth. While the color can be a disadvantage for those seeking a more natural appearance, it is generally less of an issue in the back teeth, where amalgam is most commonly used.
2. Mercury Content
The presence of mercury in dental amalgam has raised concerns over the years. Although studies show that the mercury in amalgam fillings is stable and does not pose significant health risks, some people choose to avoid amalgam due to concerns about mercury toxicity. As a result, certain patients, such as pregnant women or young children, may opt for alternative materials.
3. Brittleness
Amalgam can become brittle over time, particularly if it’s exposed to moisture or other conditions that may affect its integrity. This brittleness can sometimes lead to fractures or cracks in the filling, although this is not common.
4. Environmental Impact
The disposal of dental amalgam waste has been a concern, as mercury can be harmful to the environment if not handled properly.
Many dental offices now have special disposal systems to minimize environmental impact.
Why Dentists Choose Amalgam
Despite the rise of alternative filling materials such as composite resins, dental amalgam remains a popular choice among dentists for several reasons:
Proven track record: Dental amalgam has been used for over 150 years with a solid track record of safety and efficacy.
Strength and durability: Amalgam’s strength makes it ideal for filling cavities in areas that experience heavy chewing pressures.
Cost-effectiveness: Amalgam is a less expensive option compared to other filling materials, making it an attractive choice for patients on a budget.
Conclusion
In summary, dental amalgam is a time-tested, reliable, and affordable filling material that continues to serve as a go-to solution for many dental professionals. Its durability, strength, and cost-effectiveness make it an excellent choice for back teeth fillings. While its appearance and mercury content may be a concern for some, the material has proven to be safe and effective over the years.
