Composite Filling vs Regular Filling: What’s the Difference?

June 5, 2026

If your dentist has told you that you have a cavity, you are going to need a filling. The next question most patients ask is whether to get a composite filling or a regular one. It is a fair question, and the answer depends on a few factors: where the cavity is, how large it is, what your insurance covers, and what matters most to you. At Dentistry at Renton, we help patients make this decision every day. This guide walks through the practical differences so you can go into your next appointment informed.

What Is a Regular Filling?

A regular dental filling typically refers to dental amalgam, the silver-colored material that has been used in dentistry for well over a century. Amalgam is a mixture of metals including silver, tin, copper, and mercury. Despite the mercury content, the American Dental Association and the FDA have repeatedly confirmed that amalgam fillings are safe for most patients.

Amalgam is durable. It handles the pressure of chewing well and tends to last 10 to 15 years or longer in back teeth. It is also less expensive than composite resin, which is why it was the standard of care for decades and why some insurance plans still cover it at a higher rate.The downside is appearance. Amalgam is silver and darkens over time. For back molars that are not easily visible, this is often a non-issue. For teeth that show when you smile or speak, most patients today prefer a different option.

What Is a Composite Filling?

A composite filling is made from a tooth-colored resin material bonded directly to the tooth surface. It matches the color of the surrounding enamel closely enough that most people cannot tell it is there. Composite resin has improved significantly over the past two decades and is now strong enough for use in both front and back teeth.The bonding process for composite is different from amalgam. The dentist etches the tooth surface, applies a bonding agent, and cures the composite with a special light. This creates an adhesive bond that can actually help support the remaining tooth structure.

For patients asking which is better, composite or regular filling, composite is generally preferred for its appearance, its bonding properties, and the fact that it requires less removal of healthy tooth structure during placement. The tradeoff is cost: composite is more expensive, and in very large back molar cavities with high chewing pressure, it may not last quite as long as amalgam.

Which Is Better, Composite or Regular Filling?

The honest answer to which is better, composite or regular filling, is that it depends on the tooth, the size of the cavity, and what matters most to you.For most front teeth and premolars, composite is the clear choice. The appearance benefit is significant and the functional demands are moderate enough that composite holds up well. For large cavities in the back molars where chewing forces are most intense, amalgam has traditionally been considered more durable. That said, high-quality composite placed by an experienced dentist performs well in back teeth too.

Insurance coverage also plays a role. Some plans cover composite at the same rate as amalgam. Others cover composite at the amalgam rate and bill the difference to the patient. It is worth checking before your appointment. The team at Dentistry at Renton can help you understand your specific coverage.

What to Expect When Getting a Filling

Whether you choose composite or amalgam, the process for tooth fillings in Renton at Dentistry at Renton follows the same basic steps.

• Numbing: local anesthesia is applied so you feel no pain during the procedure. Most patients are comfortable throughout.
• Decay removal: the decayed tooth material is removed with a drill or, for small cavities, sometimes with air abrasion.
• Tooth preparation: for composite, the surface is etched and a bonding agent applied. For amalgam, the cavity is shaped to hold the material mechanically.
• Filling placement: the material is packed or layered in, then shaped to match the natural tooth contour.
• Curing or setting: composite is cured with a UV light in seconds. Amalgam hardens gradually over several hours.
• Bite check: your dentist will have you bite down and make any needed adjustments so the filling does not interfere with your natural bite.

For a broader look at how to choose the right dental treatment for your situation, read the Dentistry at Renton guide to choosing dental treatments.

Can Old Amalgam Fillings Be Replaced With Composite?

Yes. Many patients come to Dentistry at Renton specifically to replace aging or cracked amalgam fillings with tooth-colored composite. In most cases this is a straightforward procedure and results in a more natural appearance alongside a fresh, well-bonded restoration.The decision to replace a filling should be based on clinical need rather than aesthetics alone. If an amalgam filling is intact and functioning well, replacing it purely for cosmetic reasons is not always necessary. If it is cracked, worn, or developing decay at the margin, replacement makes both clinical and aesthetic sense. The dentist will advise based on what the examination shows.

Practical Tips for Tooth Fillings in Renton

If you are coming in for tooth fillings in Renton at Dentistry at Renton, these tips will help your appointment go smoothly.

• Eat before your appointment. The numbness makes eating awkward for a few hours afterward, so having a meal beforehand helps.
• Composite fillings are ready to use immediately since they cure in the chair. Amalgam fillings need a few hours to fully harden, so avoid hard or sticky foods until the following day.
• Some sensitivity to hot and cold after a filling is normal for a few days. This typically resolves on its own.
• If your bite feels off after the numbness wears off, call the office. A small surface adjustment usually resolves it in minutes.
• Bring your insurance information. Our team can review your coverage before you sit down. Visit our meet our dentists page to learn about the expertise behind every procedure at the practice.

Frequently Asked Questions About Composite vs Regular Fillings

Is composite resin as strong as amalgam?

Modern composite resin is strong enough for both front and back teeth. For very large cavities in heavy chewing areas, amalgam has traditionally been considered more durable, but advances in composite materials have narrowed that gap significantly.

Does composite cost more than amalgam?

Generally, yes. Composite costs more to place because the material is more expensive and the bonding technique takes more time. Some insurance plans cover both at the same rate, while others cover composite at the amalgam rate and bill the difference to the patient.

How long do composite fillings last?

With good oral hygiene and regular checkups, composite fillings typically last 7 to 10 years or longer. Placement quality, bite force, and oral habits all affect longevity.

Are amalgam fillings safe?

Yes. The ADA and FDA have concluded that amalgam fillings are safe for most patients. Some patients prefer to avoid amalgam due to personal preference, and composite is a fully viable alternative.

Can I choose which type of filling I get?

In most cases, yes. Your dentist will make a recommendation based on the location and size of the cavity, but patient preference is part of the conversation. Contact Dentistry at Renton to discuss your options before your appointment.

Do composite fillings stain over time?

Composite resin can pick up minor surface staining from coffee, tea, and dark foods over time, though this is typically less noticeable than darkened amalgam. Regular polishing at cleanings helps maintain the appearance.

Schedule Your Appointment at Dentistry at Renton

Whether you have a new cavity or an older filling that needs attention, the team at Dentistry at Renton will help you choose the right option for your situation. We serve patients from across the South King County area with expertise built on a UW two-year postgraduate certificate in adhesive and esthetic dentistry.

Dentistry at Renton

19221 108th Ave SE, Suite 4, Renton, WA 98055

Phone: (253) 852-4746

Email: info@dentistryatrenton.com

Hours: Monday to Thursday, 7:00 AM to 5:00 PM