How long do composite fillings really last?

The question I hear most often in my practice is deceptively simple: "How long will this filling last?" Patients deserve a straight answer grounded in evidence, not a vague reassurance.

Quick answer

Modern composite fillings, when placed with proper isolation and bonding technique, have annual failure rates of 1-3% ^[1][2]. That translates to survival rates exceeding 90% at ten years, comparable to, and in many cases better than, the amalgam fillings they replaced.

What the systematic reviews tell us

The most comprehensive data comes from Opdam and colleagues, whose 2014 meta-analysis in the Journal of Dental Research found that posterior composites placed in controlled conditions last as long as amalgam restorations ^[1]. A subsequent Swedish systematic review confirmed these findings with similar survival rates over long follow-up periods ^[2].

More recently, Josic et al. (2023) updated the evidence base with a meta-analysis comparing direct and indirect composite restorations, reinforcing that direct composites remain a highly durable option for posterior teeth ^[3].

The factors that actually matter

Filling longevity is less about the material and more about the conditions under which it is placed. The most critical factors are:

• Isolation quality: Rubber dam or equivalent moisture control makes a significant difference in bond strength and long-term retention
• Caries removal approach: The international consensus now favours selective caries removal over complete excavation, which preserves tooth structure and protects the pulp ^[4][5]
• Operator skill: Bonding protocols require attention to detail, proper etching, adhesive application, and incremental layering

When should a filling be replaced?

The conservative approach is to intervene only when there is clinical evidence of failure, secondary caries, fracture, or loss of marginal seal. The Cochrane review on carious lesion management confirms that monitoring and repairing is often preferable to replacing an entire restoration ^[6].

Frequently asked questions

Are composite fillings as strong as amalgam?

In the posterior region, modern composites perform comparably to amalgam over 10+ years ^[1]. The key advantage is that composites preserve more natural tooth structure because they bond to enamel and dentine rather than requiring mechanical retention.

Do white fillings stain over time?

Composites can discolour slightly at the margins over many years. However, this is typically a cosmetic concern, not a functional one, and can often be addressed by polishing rather than replacement.

Why does my dentist use a rubber dam for fillings?

Rubber dam isolation keeps the tooth dry during bonding. Moisture contamination is one of the primary reasons composite fillings fail prematurely. I consider it non-negotiable for any bonded restoration.

Can a composite filling be repaired instead of replaced?

Yes. When damage is localised, a small chip or marginal defect, repairing the existing restoration preserves tooth structure and is supported by the evidence ^[6].

How do I make my fillings last longer?

Maintain good oral hygiene, attend regular check-ups, and avoid using your teeth as tools. Night grinding (bruxism) is a significant risk factor, if you grind, a stabilisation splint protects both your teeth and your restorations.

When to see Dr. Khalid

If you have old fillings that concern you, or if you've been told you need a filling and want to understand your options, I'm happy to discuss what the evidence says about your specific situation. Not every filling needs to be replaced, and not every cavity needs aggressive treatment.