Does eating ice-cream make your teeth ache? Some people experience a sharp, stabbing pain when cold is applied to their teeth, almost like an electric shock. Sometimes this can also be triggered with very sweet foods. Is there something wrong with their teeth?
The answer is – not necessarily.
Sensitivity of teeth to cold and/or sweet foods and drinks is to some extent normal.
Teeth consist of an outer, hard, white layer called the enamel. Under the enamel, is a substance called the dentin. The tooth roots also consist of dentin which is covered by a different substance called the cementum. The cementum is thinner and not as hard as enamel.
The dentin has microscopic nerve fibres running through it and those nerve fibres run into the pulp tissue deep within the tooth. All these nerve fibres then connect to bigger nerve trunks that then relay information to the brain when a stimulus is applied to the tooth.
Hence, if a cold or very sweet stimulus is applied to the tooth surface, the nerve fibres just under the enamel will respond and a painful, sensation is felt. This is known as dentinal sensitivity.
The reason teeth have nerves is to tell us when something is wrong. However, just because a sensation is painful does not necessarily indicate the tooth is being harmed or damaged (pinching your skin can be painful, but it does not always damage the skin).
So, to a certain extent, the sensitivity experienced when having cold foods and drinks is normal. Same with very sweet foods.
The following picture illustrates the anatomy of a tooth, showing the nerve fibres running through the dentin from the pulp.
Fig.1
Dentinal sensitivity can be heightened if the dentin becomes exposed. This can happen if the gums recede, exposing the roots or If the enamel is worn down.
Gums can recede due to gum disease exposing the root surface of the teeth. The root surface is protected only by a thin layer of cementum which can get worn away during brushing, leaving the underlying dentin exposed and sensitive to cold and sweet stimuli. Overly aggressive toothbrushing can also wear away the enamel coating and cause exposure of the dentin and increasing sensitivity.
Figures 2 and 3 show teeth with gum recession and exposed dentin where the cementum and enamel have been worn away. The resulting exposed dentin is then sensitive.
Fig.2
Fig. 3
When can sensitivity indicate a problem with the tooth?
In normal circumstances, the unpleasant sensitivity to cold and sweet lasts only while the stimulus is being applied and disappears immediately after with no lingering effect. If one tooth however feels the cold more sharply than others, it could indicate that the dentin is exposed. This can happen when the enamel layer is worn down due to acid erosion or by abrasion from aggressive toothbrushing.
In some cases, even when the cold or sweet stimulus is removed, the painful sensation can linger and even become a severe ache with throbbing.
This could indicate an issue with the tooth pulp. This happens when a tooth has been infected with bacteria from tooth decay. If the decay has been allowed to progress deep into the tooth, the bacteria eventually spread to the pulp tissue within the tooth and trigger an inflammatory response.
The inflamed pulp leads to a more painful response to cold stimulus. The inflamed pulp also remains stimulated even after the cold stimulus is removed, leading to a lingering ache with or without throbbing. Sometimes, with an inflamed pulp, even room-temperature liquids can trigger a painful response.
When the pulp is inflamed, dental treatment is needed. If the decay is not too advanced, removing the decay and placing a filling in the tooth can fix the problem. However, if the decay has progressed too deeply into the pulp, then root canal treatment or extraction is the recommended treatment.
Figure 3 shows a tooth with decay and an inflamed nerve, causing the tooth to be hyper sensitive and painful when a stimulus is applied.
Fig. 3
What can be done to alleviate the sensitivity?
If the cause is only dentinal sensitivity, then desensitising products applied on the exposed dentin can be helpful. These work by inducing a protective material to form within the dentin, insulating the nerve fibres from painful stimuli. These products act topically and repeated applications are necessary for efficacy. Examples are desensitising toothpastes or creams (toothmousse®).
If the dentin wear is advanced, the surface can be covered with a filling material (composite) which matches the shade of the tooth. The filling will insulate the exposed dentin from stimuli and also protect the surface from further wear that happens with daily toothbrushing.
If you are concerned about your teeth being sensitive, contact us at the Melbourne Smile Clinic for an appointment. After an examination, we will determine if the sensitivity you are experiencing is benign dentinal sensitivity or if there are other issues.
Located in Melbourne Inner North, The Melbourne Smile Clinic is your dentist for Northcote, Thorbury, Fairfield, Westgarth, Clifton Hill, Preston and surrounding suburbs.
For more information or for an appointment, contact us on 9078 4471 or send us a message here