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Cracked Tooth Syndrome

Cracks in teeth can cause toothache if heading to the nerve

Summary

Cracked tooth syndrome is a term first used in the 1960s to describe a tooth that is cracked but not broken, usually the crack cannot be seen with the naked eye. The crack goes beyond the enamel of a tooth into the dentine and possibly into the nerve.

Features

Pain on biting and eating - often brought on by small hard bits of food (seeds, nuts etc)
Pain is often worse on the release of biting pressure
Pain is short lived generally only lasting while stimulus is there
Pain often brought on by pressure on a particular part (cusp) of the tooth
Can be cold/heat sensitive
Can progress to a more constant pain if crack extends into pulp - see irreversible pulpitis

Home care advice

The best treatment for cracked tooth syndrome depends on how deep the crack is. Minor cracks can be managed by.

Painkillers (paracetamol is usually the first option to try) - over 16 year olds can combine paracetamol with an NSAID (such as Ibuprofen) if necessary.
Gels that anaesthetise (numb) the area. They usually contain either Benzocaine or lidocaine.
Natural remedies such as Clove Oil which contains eugenol - a natural anaesthetic and antiseptic. If a fragment of tooth has been lost then it may be possible patch up the tooth temporarily with a DIY temporary filling kit which you should be able to get from a decent pharmacy.

Some relief may be also achieved by rubbing a sensitive toothpaste on the area either one containing Stannous Fluoride of other desenstitising agents

A major crack involving the nerve of the tooth will be harder to treat at home, go to irreversible pulpitis for more information.

PLEASE NOTE ALL THESE TREATMENTS ARE TEMPORARY FIXES AND IT IS IMPORTANT TO VISIT A DENTIST AS SOON AS YOU CAN

Causes

Isolated excessive force on a healthy tooth - A large number of teeth with cracked tooth syndrome happen in otherwise healthy teeth. Excessive forces can be applied to teeth in a one off occlusal accident such as biting on a fruit stone, an an external blow causing the teeth to clash together hard than usual or a sports injury.
Continued excessive force - Parafunctional activities such as (bruxism) tooth grinding and clenching increase the risk of cracked tooth syndrome. This may be compounded by loss of tooth tissue through acid erosion. Bruxism can be either primary (a response to stress or concentration) or secondary (caused by medical condition such as cerabral palsy or reaction to a medication or recreational drug use)
Normal forces on a compromised tooth - A tooth that has had a large filling is more vulnerable to fracture. A common issue is longstanding amalgam restorations especially in premolars involving the side of the teeth. These act like a wedge a increase the risk of fracture.
Iatrogenic damage to tooth from dental treatment - Fillings left high in the bite, adhesive fillings applied in too large increments and other restorations can increase the chance of cracked tooth syndrome.

Pain mechanism

The short, sharp pain brought on by biting is thought to be due to the fluid movements in the dentinal tubules caused by movement of the 2 parts of the tooth either side of the fracture. This then stimulates mechanoreceptors at the junction between the dentine and pulp which then activate the quick acting A-delta fibres in the dental pulp to elicit pain.

Deeper cracks may also result in pulpal inflammation as bacteria ingress towards the nerve causing the release of neuropeptides. This lowers the pain threshold of the un-myelinated C-type pain fibres in the pulp chamber. This explains the dull ache which can also be associated with cracked teeth.

Treatment

The treatment of cracked tooth syndrome depends on the extent of the fracture. If the nerve is involved and an irreversible pulpitis is present then a root canal treatment and full coverage restoration such as a crown or onlay is required.

Smaller cracks can be treated more simply. Sometimes when removing a filling from a cracked tooth the offending fragment can break off and the tooth can be restored with an adhesive restoration such as a direct or indirect inlay/onlay.

Historically cracked tooth syndrome was first treated with a copper band or orthodontic band around the tooth to confirm the diagnosis and check if an irreversible pulpitis is present. This would be followed by a full gold crown (after root filling if necessary). However bands are difficult to apply and can be traumatic to the gums. A technique called composite splinting is a more practical and often successful option. This involve removing a small amount of tooth over the cracked area and covering with an adhesive filling material to hold the crack in place. This can in some cases also be the final restoration.

Although a gold restoration may still be considered the standard by some centres, recent improvements in adhesive materials mean that composite filling materials (especially if overlaying the cusps of the tooth) or porcelain onlays can be used with good success rates. These adhesive methods have the benefit of being much more cosmetically acceptable and are less destructive to the tooth than a conventional crown.

References

Acute dental pain I: pulpal and dentinal pain - Matti Närhi, Lars Bjørndal, Maria Pigg, Inge Fristad and Sivakami Rethnam Haug Nor Tannlegeforen Tid
2016; 126: 10—8

Cracked tooth syndrome. Part 2: restorative options for the management of cracked tooth syndrome - S. Banerji, S. B. Mehta and B. J. Millar BRITISH DENTAL JOURNAL VOLUME 208 NO. 11