Cracked Tooth ?
Cracked tooth syndrome often starts out as an occasional sharp pain in a back tooth when biting expectantly on something hard, such a baked whole grain in bread or a chop bone. The pain occurs more frequently with time until you cannot bite on the tooth at all and the tooth becomes very sensitive to cold temperature. The pain can be erratic, can come and go and finding the source of the pain can be unreliable, particularly in the early stages.
Are cracks common?
Cracks can occur in any teeth, but most often in back chewing teeth (premolars and molars). Teeth receive heavy stresses during chewing and these stresses can lead to stress fractures within the tooth structure. It is very common for cracks to develop within the enamel of front teeth with age and these are easily seen with a good mirror and lighting. Where cracks develop in the dentine (inner layer of teeth) these cannot be seen until they are so advanced that they have spread through to the enamel. So a visible crack in the enamel may be superficial, common and of no concern OR it could be the extension of a crack that has started inside the tooth. Cracks do not show on xrays. Cracks that run to the surface of a tooth and are visible are rarely dangerous to the survival of a tooth. However they can cause pain and irritate the pulp tissue inside the tooth (pulpitis) in some cases requiring root canal therapy.
Why does it hurt when I bite? (Technical stuff)
Stress fractures within teeth cause increased flexion or bending when chewing force is applied to the tooth in the right direction. This means that at a microscopic level the crack opens and closes with each cycle of chewing force (cyclic loading). The opening and closing of the crack and associated flexion in surrounding tooth structure causes fluid to flow into and out of the crack (microleakage) and a change in fluid pressure in the dentine which connects directly with nerve fibres in the dental pulp. Nerve stimulation results in PAIN. microleakage also provides a pathway for acids and bacteria from the mouth to penetrate deeper into the tooth, also irritating the pulp tissue leading to pulpitis and even pulp tissue death.
Cracks can be different
Most cracks occur in back teeth that have been greatly weakened by tooth decay or other trauma. A cavity into the middle of a tooth undermines and weakens the cusps. In these cases, the crack starts at the base of a cusp and runs to the surface. Ultimately the cusp falls off, sometimes with pain. but also often without any preceding pain or warning. Where this occurs on the inside of a lower molar, the greatest inconvenience is the ulcer on the side of the tongue that results from a sharp edge.
- Often the gap left by a chipped cusp feels HUGE, but it may only need smoothing off.
- A medium chipped cusp may require a simple addition of direct filling.
- A larger chipped cusp may require a simple filling retained with a pin.
Cracks can also start deeper within the tooth structure. This sometimes occur in teeth with very small fillings or even no fillings at all. These cracks are much more dangerous and if the crack runs down into the root of the tooth can lead to pulp death and even the loss of the tooth.
- A larger cusp fracture may require management with a crown and possibly root canal treatment.
- A fracture into the root of the tooth with result in loss of that tooth.
The extent of the involvement of the cracking in the tooth, the strength of the remaining tooth structure and health of the pulp tissue will determine whether the problem is of no significance, minor, major or catastrophic.
If you think you have a cracked tooth, it’s important to seek treatment quickly, before the problem gets worse. Once treated, most cracked teeth continue to function and provide years of comfortable chewing.
Make on appointment on 6224 3575
DR. MALCOLM J. GRENNESS
BD.Sc., L.D.S., M.Med.Sc., PhD, F.R.A.C.D.S
Call: (03) 6224 3575
158 Collins Street, Hobart
Monday – Friday 8.45am-5.15pm
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