You might see “filling” on one treatment plan and “bonding” on another, and both describe the same white material being added to a tooth. That is because the two usually are made of the same thing: tooth-coloured composite resin. What separates them is the reason for the work. A filling repairs a tooth that has been damaged by decay or a break. Bonding changes how a healthy tooth looks.
Ask what the composite is fixing
Composite starts as a soft, mouldable paste, is shaped onto the tooth and is then hardened with a curing light. Used to fill the hole left after decay is removed, or to rebuild a broken corner, it is a restoration: a filling. Used to close a small gap, smooth a chip on an otherwise sound tooth, or lengthen a short tooth for appearance, it is cosmetic bonding.
The hands-on technique is similar. The purpose changes the preparation, how the work is coded, whether a health fund contributes, and what it needs to withstand.
Signs the tooth needs a filling
A filling is needed when something is wrong with the tooth itself: a cavity, decay found on an X-ray, a cracked or broken section, or an old filling that has failed. Decay that is left tends to spread deeper towards the nerve, and once it reaches it, the fix becomes a root canal rather than a filling. Removing the decay and sealing the tooth stops that progression.
Because decay has to be cleared away, a filling often involves drilling and local anaesthetic. Our article on what to expect when getting a filling walks through the appointment, and the dental filling cost guide covers typical market price ranges.
Where bonding fits
Bonding is for a tooth that is healthy but that you would like to look different. Typical examples are a small chip on an edge, a minor gap between front teeth, a tooth that is slightly short or misshapen, or a mark that whitening will not shift. Little or no tooth is usually removed and numbing is often unnecessary. The bonding procedure article explains the visit step by step.
For bigger changes in shape or colour, or where stain resistance matters a lot to you, veneers may be worth comparing. Our guide to composite bonding versus veneers sets out the trade-offs.
| Filling | Cosmetic bonding | |
|---|---|---|
| Reason | Decay, a fracture or a failed filling | Shape, size or appearance of a healthy tooth |
| Material | Usually composite | Composite |
| Tooth removed | Decayed or damaged tooth | Little or none |
| Anaesthetic | Often | Often not needed |
| Health fund | Often claimable under extras | Usually treated as cosmetic |
Why your health fund treats them differently
Funds generally contribute to restorative work, which includes fillings, within your extras limits and waiting periods. Composite added only to improve appearance is normally classed as cosmetic, and most funds do not pay towards it. That is why the reason for the work, and the item numbers on your quote, matter more than the material. Check the item numbers with your fund before treatment if cover is important to you.
How long each lasts depends on the tooth more than the name
Composite is durable but not permanent, and the same factors wear it down whether it was placed as a filling or as bonding.
For fillings in back teeth, a large analysis of long-term studies (Opdam and colleagues, Journal of Dental Research, 2014) found that new decay and fracture were the main reasons composite fillings failed. Failure was more likely in people at high risk of decay and in larger fillings covering more surfaces of the tooth.
For bonding on front teeth, a study of composite used to repair fractured teeth and close gaps (Lempel and colleagues, Dental Materials, 2017) reported about 88% survival at up to 10 years, with chipping most common in the first year.
In both cases, brushing well with fluoride toothpaste, cleaning between teeth, keeping up check-ups, not using teeth as tools and wearing a guard if you grind all help. A chipped or worn edge can usually be repaired by adding more composite.
Sometimes it is both
The line is not always sharp. An old front filling that has started to leak and has also darkened can be replaced with a new, better-matched restoration, which repairs the tooth and improves its look at the same time. Bonding also cannot treat a cavity on its own: any decay has to be removed first. After an examination, the dentist can tell you which category your tooth falls into and why.
One practical point: whitening gels do not lighten composite. If you are planning whitening, it is usually done before front-tooth bonding or fillings so the composite can be matched to the lighter shade.
Not sure which your tooth needs?
A short assessment usually answers it. For appearance goals, Lumi Dental offers a free cosmetic consult, and you can read more about our composite bonding service.
This article is general information and is not a substitute for personal dental advice. For advice about your own teeth, please see a dentist.
