Are teeth bones? What your teeth are actually made of

Are teeth bones?

No. Teeth and bones are both hard, white, mineral-rich structures built largely from calcium and phosphate, which is why the question is a fair one. But they are made differently, behave differently and, crucially, repair differently. Bone is living tissue with its own blood supply and cells that constantly break down and rebuild it; a fractured bone knits back together. Teeth are made of three distinct layers, and the outer one, enamel, contains no living cells at all. Once enamel is chipped, worn or dissolved by decay, the body cannot grow it back.

The confusion is understandable. Teeth sit in bone (the jaw), they show up on x-rays like bone, and they survive long after the rest of the body has gone, which is why archaeologists lean on them. But a tooth is better thought of as a highly specialised organ than as a piece of skeleton.

	Teeth (enamel and dentine)	Bones
Main mineral	Calcium phosphate (hydroxyapatite), about 96% of enamel	Calcium phosphate, about 65–70% by weight
Living cells	None in enamel; few in dentine; living pulp inside	Throughout; constantly remodelled
Blood supply	Only in the pulp	Yes, throughout
Can it heal?	No; enamel never regrows, only microscopic remineralisation	Yes; fractures knit back together
Collagen	Almost none in enamel	About a third of bone is collagen, giving it flexibility
Hardness	Enamel is the hardest substance in the body	Softer than enamel
Visible on x-ray	Yes	Yes

What a tooth is made of

Victoria’s Better Health Channel describes a tooth in two parts: the crown, which is the part you can see above the gum, and the root, which anchors it in the jaw bone. Inside, there are four tissues.

• Enamel is the hard white outer shell of the crown. It is about 96 per cent mineral, has no nerves or blood supply, and is harder than bone. It is also brittle, and it is the only part of a tooth that cannot repair itself in any way.
• Dentine is the yellowish layer beneath the enamel that makes up most of the tooth. It is softer than enamel, slightly porous, and carries tiny tubules that run to the nerve, which is why exposed dentine is sensitive to cold and sweet. Dentine can lay down a little new tissue from the inside over a lifetime, but it cannot rebuild what is lost at the surface.
• Pulp is the soft living centre of the tooth, with blood vessels and nerves. It senses temperature and pressure and keeps the dentine alive. Deep decay or a crack that reaches the pulp is what causes a toothache and usually leads to a root canal or extraction.
• Cementum is a thin bone-like layer covering the root, to which the periodontal ligament attaches and holds the tooth in its socket. Gum recession exposes cementum, which wears away easily.

Around the tooth, the gum and the periodontal ligament act as a shock absorber and seal. Gum disease attacks these supporting tissues rather than the tooth itself, which is why teeth can be lost even when they have no decay.

Why enamel does not grow back

Bone heals because it is full of cells (osteoblasts and osteoclasts) that remodel it. Enamel is formed by cells called ameloblasts while the tooth is developing under the gum, and those cells are lost when the tooth erupts. There is nothing left to make more. That is why a chipped tooth needs a filling or bonding rather than time, and why a cavity never closes on its own.

What enamel can do is remineralise at a microscopic level. The early stage of decay is minerals leaching out of the enamel surface; fluoride in toothpaste and tap water, and the minerals in saliva, can push some of them back in and harden the surface again before a hole forms. That is the whole logic of fluoride toothpaste, and why dentists can “watch” an early white spot rather than drill it. Once the surface collapses into a cavity, remineralisation cannot fill it.

Ten more teeth facts worth knowing

1. Enamel is the hardest substance in the human body, harder than bone, but it can still be cracked by ice, popcorn kernels or grinding at night.
2. Adults have 32 teeth including wisdom teeth, children have 20. Because wisdom teeth are so often missing or removed, 28 is the everyday adult number. See how many teeth adults and children have.
3. Teeth start forming before birth. Baby teeth begin developing in the jaw at around six weeks of pregnancy, and the enamel of the adult front teeth is forming in the first years of life, which is why early childhood illness or very high fluoride intake can leave marks on adult teeth.
4. No two sets are the same. Like fingerprints, the shape, spacing and wear of teeth are unique, which is why dental records are used for identification.
5. Teeth are the only part of the body that cannot heal themselves in the way skin or bone does. Everything a dentist does is, in a sense, replacing what the body cannot.
6. Saliva is your teeth’s best defence. You produce about a litre a day, and it neutralises acid, washes away food and delivers minerals for repair. A dry mouth from medicines or dehydration sharply raises decay risk.
7. Most decay happens between teeth and in the grooves of molars, the two places a toothbrush does not reach well. That is the case for flossing and, for children, fissure sealants.
8. Teeth are not naturally bright white. Enamel is slightly translucent, and the dentine beneath is yellowish, so natural teeth are off-white and darken with age as enamel thins. Whitening products sold directly to Australian consumers are limited to 6 per cent hydrogen peroxide; see our teeth whitening guide.
9. Tooth sensitivity usually means exposed dentine, from gum recession, erosion or grinding, rather than a cavity. Our sensitive teeth guide explains what helps.
10. Gum disease, not decay, is the leading cause of adult tooth loss in Australia, and about three in ten adults have moderate to severe periodontitis. Our gum disease guide covers the warning signs.

Why the answer matters for your dental bills

Because enamel does not regrow, dentistry is almost entirely about prevention and replacement, and replacement gets more expensive the longer a problem is left. In the ADA’s most recent published fee survey data, a routine check-up with scale and fluoride averaged about $219 and a one-surface filling about $167 to $178, while a single dental implant to replace a lost tooth is indicatively $4,500 to $7,000 in 2026. Catching a white spot before it becomes a cavity, or a cavity before it reaches the pulp, is the cheapest dentistry there is.

The practical takeaways are the same ones every dentist repeats: brush twice a day with fluoride toothpaste, clean between your teeth, drink tap water, keep sugary and acidic drinks to mealtimes, wear a mouthguard for contact sport and see a registered dentist every six to twelve months. For what those visits and treatments typically cost, see our guide to dental costs in Australia.

Common questions