Composite vs amalgam vs GIC: dental fillings compared

Composite, amalgam and glass ionomer cement (GIC) are the three filling materials most people in India will be offered, and they differ in appearance, strength and how they behave in the mouth. Composite is tooth-coloured, bonds directly to the tooth and now handles most everyday cavities. Amalgam is the older silver metal filling: extremely durable, considered safe by major health bodies, yet steadily being phased down worldwide. GIC is a fluoride-releasing cement that suits children, gumline cavities and interim work, which is why our clinic in Viman Nagar relies on composite and GIC for nearly all fillings.

The three materials at a glance

Composite resin is a tooth-coloured blend of resin and finely ground glass that bonds directly to the tooth. Because it comes in many shades, a well-placed composite is close to invisible, and because it sticks to enamel and dentine, the dentist usually needs to remove less healthy tooth to anchor it. It sets on demand under a curing light, so a filling can usually be completed and polished in a single visit. For most cavities in most mouths, it is now the default choice.

Dental amalgam is the silver-grey metal filling older generations grew up with. It is an alloy of silver, tin and copper mixed with mercury, packed firmly into the cavity, where it hardens into an extremely durable plug. It does not bond to the tooth, so the cavity must be shaped with mechanical undercuts to hold it, which sacrifices some sound tooth structure. It withstands heavy chewing forces well, which is why it served for so long as the workhorse of back-tooth dentistry.

Glass ionomer cement, usually shortened to GIC, is a self-setting material made from glass powder and an organic acid. It bonds chemically to the tooth, tolerates a little moisture during placement, and slowly releases fluoride, which helps protect the surrounding tooth from new decay. Its trade-off is strength: it wears faster than composite or amalgam under chewing pressure, so it earns its place in specific situations rather than as an all-purpose filling.

How each filling looks in the mouth

Appearance is the difference patients notice first. Composite comes in a range of shades and translucencies, so it blends into the tooth and is the standard choice anywhere a filling might show, from front teeth to premolars. Amalgam is unmistakably silver, and over the years it can darken and lend a greyish tinge to the surrounding tooth. GIC is tooth-coloured but more opaque and less polishable than composite, so it looks acceptable rather than invisible, which matters little on a baby molar and rather more on a front tooth.

Durability and where each material suits

No single material wins everywhere; the right choice depends on the tooth, the size of the cavity and the forces it must survive. Composite handles most small and medium cavities in front and back teeth. Amalgam's raw strength suited very large cavities in molars, which is where you will still find most old amalgams doing quiet service. GIC suits baby teeth, cavities at the gumline, mouths with a high decay rate and interim fillings. If you are unsure what your tooth needs, a standard cavity filling appointment begins with an examination, an X-ray where needed, and a material chosen tooth by tooth.

The mercury question, answered honestly

Amalgam contains mercury, and that word understandably worries people. The honest position, supported by the World Health Organization, the FDI World Dental Federation and other major health bodies, is that mercury bound within a set amalgam filling behaves very differently from free mercury, and set fillings have not been shown to harm the general population. If you have sound, comfortable amalgam fillings, the standard advice is to leave them alone, because drilling out a healthy filling removes more tooth and briefly releases more mercury vapour than simply leaving it in place.

At the same time, amalgam use is genuinely declining. The Minamata Convention, an international environmental treaty that India has joined, commits countries to phase down amalgam, chiefly because of mercury's environmental footprint rather than proven harm to patients. Many clinics, ours included, no longer stock it, because modern composites cope with most situations where amalgam was once the only sensible option. As a precaution, amalgam is usually avoided in pregnant women, young children and people with kidney disease, and anyone with a confirmed metal allergy should tell their dentist before any filling.

Why we place composite and GIC

At our Viman Nagar clinic we place composite and GIC rather than amalgam. Composite fillings cover most everyday cavities because they conserve tooth structure, look natural and can often be repaired rather than wholly replaced if they chip. GIC earns its place where it genuinely outperforms composite: baby teeth, cavities at the gumline and interim fillings placed while a tooth settles. Dr. Puja Bansal, who has 27 years of experience and leads every case, selects the material tooth by tooth, and deep cavities close to the nerve are first assessed with consultant endodontist Dr. Mrunal Godse.

For children, our consultant paediatric dentist Dr. Vanessa Lobo often prefers GIC on baby molars, because its fluoride release helps protect teeth that small hands find hard to brush well. On cost, what you pay depends on the material, the size and position of the cavity, how many surfaces are involved and whether decay has reached the deeper layers of the tooth. We explain these factors and give a written itemised estimate after examining the tooth, never a figure over the phone. Our guide to what a tooth filling costs in Pune walks through each factor in detail.

Sources & further reading: American Dental Association (MouthHealthy); NIDCR, US National Institute of Dental & Craniofacial Research; NHS, Dental Health; Indian Dental Association.