What Are White Fillings Made Of?

If you're considering white dental fillings, you may want to know exactly what goes into them.

White fillings are made from composite resin, a tooth-coloured material that has evolved significantly over the years.

Understanding what composite resin is made of and how it bonds to your tooth can help make sense of why white fillings look natural, preserve tooth structure, and hold up to everyday biting and chewing.

What Material Is Used In White Fillings?

"White fillings are made of composite resin, a tooth-coloured filling material containing a resin base (typically Bis-GMA) mixed with microscopic glass or ceramic particles.

The composite comes in a wide range of shades and translucencies, allowing dentists to blend materials to closely match your natural colour. "

Dr Mark Flynn

A white filling bonds directly to the tooth using an adhesive.

The tooth surface is conditioned first, followed by the bonding agent, which creates a strong chemical and micromechanical connection between the filling and the tooth.

The composite material is then applied in controlled layers and hardened with a curing light.

Layering helps rebuild the tooth's natural shape and ensures the material is properly cured throughout.

Once the dental filling is in place, it's shaped and polished to blend with the surrounding teeth.

How Have White Filling Materials Improved Over Time?

Composite materials have improved considerably over the years.

Earlier versions were more likely to wear down and discolour, while modern composite formulas offer better strength, wear resistance, polish, and colour stability.

Newer composites use finer glass and ceramic particles alongside advanced resin formulas.

Some materials include fibre reinforcement to help support the tooth and reduce the risk of cracking under pressure.

Are Modern White Fillings Better Than Older Ones?

Modern composites offer a better balance of strength, durability, and natural appearance than earlier materials.

However, the material is only one factor in how long a white filling lasts.

The size and location of the filling, chewing pressure, oral health, and how well it's placed all impact its lifespan.

Even with all the improvements in composite technology, good white fillings still depend completely on the quality of the technique used by the dentist.

How Do White Fillings Compare To Silver Amalgam?

Composite and amalgam differ in how they're made, how long each takes to place, and where the UK regulations currently stand on their use.

What Is The Difference Between White And Silver Fillings?

White fillings are made primarily from composite resin and are designed to blend closely with the natural tooth.

Traditional silver-coloured, or amalgam, fillings consist of an alloy containing mercury, silver, tin, and copper.

Amalgam has a strong clinical track record, but it's a more basic material than composite.

Composite bonds directly to the tooth, while amalgam is held mainly by the shape of the cavity, meaning more tooth structure needs to be removed to fit it securely.

Composite's more conservative approach, along with the absence of mercury, is why many patients consider white fillings the safer option.

What Makes White Fillings Take More Time?

White fillings take longer because they require precise bonding and careful moisture control.

Composite is more technique-sensitive than amalgam, so even small amounts of contamination can compromise the seal and raise the risk of tooth decay developing underneath and broken fillings.

"At The Modern Dentist, we use rubber dam isolation when placing composite to keep the tooth and working area clean and dry throughout the process."

Dr Mark Flynn

The same protection is equally important when removing amalgam, helping prevent debris from being ingested.

Is Amalgam Being Phased Out In The UK?

The use of dental amalgam is being phased down in the UK as part of efforts to reduce mercury usage, with restrictions now applying to certain patients.

However, this doesn't mean that existing amalgam fillings need to be removed.

If they are sound and clinically appropriate, there's generally no need to replace/remove them just because they’re made from amalgam.

Are There Different Types Of White Filling Material?

“White filling” covers several materials, which are chosen based on the size, location, and demands of the cavity.

• Standard composite resin: The most common option, placed in layers and suitable for most cavities.

• Bulk-fill composite: Placed in fewer, thicker layers. Often used for larger areas of decay.

• Nano-composite: Made with extremely fine particles for excellent polish and long-lasting colour. Frequently chosen for front teeth and visible fillings.

• Glass ionomer cement (GIC): A different tooth-coloured material used for temporary fillings, baby teeth, or cases where bonding isn't possible. It releases fluoride but isn't as durable as composite.

There's no single best option for every patient.

At The Modern Dentist, we choose the material based on your tooth's size, location, chewing pressure, and how noticeable the restoration will be.

Is The Material In White Fillings Safe?

Yes, composite has a well-established safety record and is widely used to fill cavities in dentistry.

Some composites contain BPA-derived compounds, though pure BPA isn't added intentionally.

Any traces released are minimal, and current evidence doesn't point to a health risk at these levels.

If you're concerned, The Modern Dentist can help you explore your options and choose an alternative formulation where it's appropriate.