Amalgam Fillings vs. Composite Fillings: Which is Better?

When it comes to repairing cavities, dental fillings are a cornerstone of restorative dentistry. However, the choice between amalgam and composite fillings can significantly influence the success of the treatment and the long-term health of your teeth. Each option comes with its unique benefits, drawbacks, and considerations. This in-depth comparison will help you understand which filling material suits your specific needs.

What Are Amalgam Fillings?

Amalgam fillings, often referred to as silver fillings, are made from a mixture of metals including mercury, silver, tin, and copper. These fillings have been used in dentistry for over 150 years and are renowned for their strength and affordability.

The mercury in amalgam binds the other metals together, creating a durable and resilient material. This strength makes amalgam fillings an excellent choice for molars and teeth exposed to significant chewing forces. Despite their durability, amalgam fillings are easily noticeable due to their metallic appearance, which can make them less desirable for visible teeth.

What Are Composite Fillings?

Composite fillings, also known as tooth-coloured fillings, are crafted from a blend of resin and finely ground glass particles. This material mimics the natural colour of teeth, allowing for a seamless and aesthetic restoration.

Composite fillings bond directly to the tooth structure, creating a strong, yet less rigid connection compared to amalgam. This material is ideal for smaller cavities and visible teeth, as it provides a natural look that matches the surrounding enamel. Additionally, the bonding technique used for composite fillings often requires less removal of healthy tooth structure, preserving more of the natural tooth.

Key Differences Between Amalgam and Composite Fillings

1. Durability: Lifespan of Amalgam vs. Composite Fillings

• Amalgam Fillings:
  Known for their impressive durability, amalgam fillings can last anywhere from 10 to 15 years or longer with proper care. They are highly resistant to wear, making them ideal for teeth subjected to heavy chewing forces, such as molars. However, although the amalgam fillings themselves may last a long time, they can also contribute to cracks and fractures of the the teeth themselves, especially if one is grinding their teeth – similar to “hammering a metal nail through a sheet of glass”.
• Composite Fillings:
  While composite materials have improved significantly over the years, their lifespan typically ranges from 5 to 10 years. They are more prone to chipping and wear, especially in areas where teeth are exposed to intense pressure, and where there is more filling than tooth structure.

2. Appearance: Aesthetic Appeal of Tooth-Colored Fillings vs. Silver Fillings

• Amalgam Fillings:
  The metallic colour of amalgam fillings makes them easily noticeable, even in areas in the back of the mouth, which can also become visible when one is yawning, singing, or laughing. Over time, they can also cause discolouration in the surrounding tooth structure, creating a greyish tint.
• Composite Fillings:
  Composite fillings are virtually indistinguishable from natural teeth. They are custom-shaded to match your enamel, making them an excellent choice for visible areas. 

3. Procedure: Time Required and Techniques Used for Placement

• Amalgam Fillings:
  The placement process for amalgam fillings is relatively straightforward and less technique-sensitive. The filling is packed into the prepared cavity and shaped before hardening, usually completed in a single visit.
• Composite Fillings:
  Composite fillings require a more intricate process. The tooth is first cleaned and prepped, followed by the application of a bonding agent. The composite material is then applied in layers, with each layer hardened using a special curing light. This meticulous process can make the procedure longer.

4. Health Considerations: Mercury in Amalgam Fillings vs. BPA in Composites

• Amalgam Fillings:
  The presence of mercury in amalgam fillings has raised health concerns. Although studies indicate that the small amount of mercury released is not harmful to most people. In accordance with the Minamata Convention, the Australian Dental Association (ADA) states in its Policy Statement 6.18 “that after 1 January 2024 amalgam can only be used in its capsulated pre-dosed form, and the use of bulk mercury is prohibited,” and that “the Convention strongly discourages the use of amalgam in deciduous teeth, patients under 15 years of age and pregnant women, except when considered necessary and based patient needs.”
• Composite Fillings:
  Composite fillings may contain trace amounts of BPA, a chemical linked to potential health risks. However, most modern composites are BPA-free or contain negligible amounts, making them a safer alternative for concerned patients.

Pros and Cons of Amalgam Fillings

Pros:

• Extremely durable, especially for molars.
• Less technique-sensitive, ensuring consistent outcomes; often used in public health systems

Cons:

• Metallic appearance can be unappealing.
• Mercury content raises health concerns for some individuals.
• Requires removal of more healthy tooth structure during placement.
• Can contribute to cracks and fracturing of teeth

Pros and Cons of Composite Fillings

Pros:

• Aesthetic appeal with a natural, tooth-coloured appearance.
• Minimally invasive, preserving more of the natural tooth.
• Versatile application for various dental issues.

Cons:

• Shorter lifespan, especially in high-pressure areas; a porcelain crown should be considered instead
• Susceptible to staining over time, especially from coffee, wine, or smoking.

Maintaining Dental Fillings

Proper maintenance can significantly extend the lifespan of your dental fillings:

1. Practice Excellent Oral Hygiene: Brush and floss daily to prevent further decay around the filling and help prolong the lifespan of the dental fillings.
2. Regular Dental Visits: Schedule check-ups to monitor the condition of your fillings and address potential issues early.
3. Avoid Damaging Habits: Refrain from chewing ice, biting your nails, or grinding your teeth. Use a mouthguard if necessary.
4. Limit Staining Foods: Minimise exposure to coffee, red wine, and tobacco to maintain the appearance of composite fillings.

Conclusion

Most patients opt for white fillings, seeing this as a more “natural” replacement of missing tooth structure, and the technological advances have come a long way, but consult your dentist to determine the most suitable option based on your oral health. 

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