What is a Broken Tooth? How is a Broken Tooth Treated?

A Tooth Fracture and Its Common Causes

A tooth fracture is a crack or a complete break in the enamel, the dentine beneath it or the deeper layers of the tooth. It happens when a force meets a tooth that cannot absorb it, either because the force is sudden, as in a fall, or because the tooth has already been weakened. Fractures range from a painless line in the enamel to a crack that runs into the root and splits the tooth, and the depth of the break decides the treatment.

Biting hard objects such as ice, hard sweets or nut shells is a frequent cause. Falls, traffic accidents and blows to the face are another. Grinding teeth at night loads the teeth for hours without the person noticing, and over time this can open cracks. Teeth with large old fillings, teeth left without a protective crown after root canal treatment and enamel thinned with age all break more easily under ordinary chewing.

Sport deserves a separate mention. Sports account for 10% to 42% of facial fractures, a group that includes fractures of the jaw (PubMed 28314422). A meta-analysis of mouthguard studies found that in 12 cohort trials the overall risk of orofacial injury was 2.33 times higher in athletes who did not wear a mouthguard (PubMed 31148073). A fracture is not always visible at first, so a tooth that has taken a knock deserves a look even when it seems intact.

Types of Tooth Fracture From Craze Line to Root Fracture

Tooth fractures are grouped by where the crack runs and how deep it goes, and each type carries a different outlook.

An enamel crack, often called a craze line, is a fine superficial line in the outer enamel. It usually causes no pain and is mainly a cosmetic matter; many adults have several on their front teeth.

A fractured cusp is a break in which part of the chewing surface comes away. It is typical of back teeth with large fillings, where the remaining wall has become thin, and the person often feels a sharp edge with the tongue.

A vertical crack starts on the chewing surface and runs down towards the root. It usually hurts when biting, especially when the bite is released, because the two sides of the crack move slightly apart.

A split tooth is the later stage of a vertical crack, in which the tooth has separated into two parts. At this point the tooth usually cannot be kept and extraction is required.

A vertical root fracture begins inside the root and travels upwards. It can progress for a long time without symptoms and often comes to light only when the gum over the root becomes infected. Root-filled teeth are more prone to it, and because the crack is hidden below the gum it is one of the harder fractures to diagnose.

Symptoms and How a Dentist Diagnoses a Fracture

A crack that stays within the enamel can go unnoticed for years, while a deeper one shows itself through a small group of recurring signs. These are sensitivity to hot and cold, a sudden sharp pain when chewing, discomfort when pressure is applied, swelling of the gum next to the tooth and a sharp edge that catches the tongue. After an accident there may also be bleeding in the mouth. Pain that comes and goes and is hard to pin to one tooth is typical of cracks.

Diagnosis takes more than a glance. The dentist first examines the tooth under a bright light and with magnification, looking for a line in the enamel or a missing piece. Dental radiographs are needed when the crack may reach the root. Transillumination, in which a strong light is shone through the tooth, shows whether the light is interrupted by an internal crack. A percussion test, gently tapping the tooth, and a bite test on each cusp in turn help identify which tooth and which part of it hurts.

Vertical root fractures may not show clearly on standard radiographs. The dentist then combines the pattern of symptoms, the gum findings around the root and, where needed, further imaging before giving an answer. A clear diagnosis decides whether the tooth can be restored or needs a different plan.

Treatment Chosen by the Depth of the Fracture

The treatment plan follows the type, size and position of the fracture. The deeper the break, the more the tooth needs.

When only the enamel surface is chipped or cracked, the tooth can be repaired with a composite aesthetic filling, matched to the colour of the tooth and bonded in a single visit. When a large part of the tooth has been lost, a filling alone is too weak for chewing, and the tooth is covered with a porcelain or zirconia crown that holds the remaining structure together.

When the fracture reaches the pulp, the nerve and blood vessel tissue inside the tooth, the pulp is dealt with before the tooth is rebuilt. In a mature tooth this is often root canal treatment, followed by a filling or crown. In some fractured front teeth only the exposed top part of the pulp is removed, a procedure called pulpotomy, which aims to keep the rest of the pulp alive. A systematic review of seven retrospective studies on pulpotomy for complicated crown fractures in permanent teeth reported success rates ranging from 75% to 96% (PubMed 35076954). In the one study that compared methods, pulpotomy succeeded in 90.9% of cases against 67% for pulp capping, and the authors advised caution because the studies were small with a moderate risk of bias (PubMed 35076954).

When a crack has split the tooth in two, the tooth usually cannot be saved. It is extracted, and an implant or a bridge is considered so that the gap does not stay empty. Cracks at the root tip that root canal treatment cannot resolve may call for apical surgery, in which the root tip is removed through the gum.

Restorative Materials and Their Roles

Several materials are used to rebuild a broken tooth, and each has its own place.

Composite fillings are tooth-coloured resins bonded directly to the tooth. They suit small and medium fractures, particularly on front teeth, where colour matching matters and the repair can be finished in one appointment. Their limit is strength over large areas under heavy chewing.

Porcelain and zirconia crowns are made in a laboratory from a scan or impression of the prepared tooth. They cover the whole visible part of the tooth and are chosen when a large piece has been lost or when a root-filled tooth needs protection against splitting. Zirconia is stronger, while layered porcelain imitates the translucency of natural enamel.

Glass ionomer fillings bond to the tooth and release fluoride. They are mainly used as temporary or intermediate fillings, for example while a crown is being made.

A fibre post is placed inside the root canal of a root-filled tooth when too little crown remains to hold a filling or crown, and it supports the core the crown will sit on. The choice depends on how much of the tooth is left, its position in the mouth and whether the pulp has been treated.

What to Do in the First Hour After a Break

A broken tooth becomes an emergency when the fracture is close to the nerve or follows an accident. Bleeding from the tooth, severe pain or a tooth knocked out completely are reasons to see a dentist without delay.

If a piece of tooth has come away, keep it in a clean container and bring it to the appointment, because in some cases it can be bonded back. Rinse the mouth gently with warm water and do not try to treat the tooth yourself. If the gum or lip is bleeding, press a clean piece of gauze on the area for several minutes. Painkillers can be taken for pain, but aspirin should be avoided because it can increase bleeding. Until the tooth is seen, chew on the other side and avoid very hot, very cold and hard foods.

A fracture that does not hurt still needs to be assessed. Enamel and dentine cannot repair a break on their own, so the fracture stays open. Bacteria collect in the gap, and over time this can lead to decay and infection of the pulp. Vertical root fractures in particular can progress quietly and show themselves only when an infection develops, so early assessment keeps more options open.

Recovery Times After Each Treatment

Recovery depends on the method used. A composite filling is usually completed in a single session, while a crown or root canal treatment typically takes 2 to 3 sessions.

After a filling, mild sensitivity to hot and cold may last a few days. Pain after root canal treatment usually eases within 3 to 5 days, and ordinary painkillers are generally enough. After a crown is fitted, it can take a few weeks for the bite to feel entirely natural. If a surgical procedure such as apical surgery or an extraction was carried out, healing of the soft tissues takes 1 to 2 weeks.

During recovery, soft foods and chewing on the other side reduce the load on the treated tooth, and a temporary filling or crown should be spared from sticky and hard foods until the final restoration is in place. Pain that grows stronger after the first few days, swelling of the face or gum, or a restoration that feels high when biting are reasons to be seen before the planned follow-up.

Preventing Fractures in Sport and Daily Life

Traumatic dental injuries are common. A meta-analysis of 102 studies put their pooled prevalence at 15.2% in the permanent dentition and 22.7% in the primary dentition (PubMed 29455471). Many breaks can still be prevented with a few habits.

A mouthguard is a well-studied measure in sport. Across eight studies of athletes in contact sports, dento-alveolar trauma occurred in 7.75% of mouthguard users against 48.31% of non-users, an odds ratio of 0.18 (PubMed 30222244). A guard made from an impression fits more closely than a ready-made one, which makes it more likely to be worn throughout training and matches.

Daily habits matter as much. Ice, hard sweets and nut shells should not be broken with the teeth. People who grind their teeth at night benefit from a night guard, which spreads the load. Keeping decay under control prevents the thin walls that break easily, and teeth that have had root canal treatment should be checked regularly, since they fracture more readily. Where teeth show heavy wear, restorative support can rebuild lost structure before a break occurs. At examination, the dentist looks at old fillings, root-filled teeth, signs of grinding and existing cracks, and plans protection around them.