Many people suffer from tooth hypersensitivity for some degree. Hypersensitivity to cold or hot or even certain foods that are acidic is fairly common in about 15% of my patients . Some have it worse that others and sometimes it is intermittent to just about all the time. It can be mild or more severe depending on the cause.
I am doing to discuss causes just by sensitivity of teeth without any decay or infection. This is usually caused by teeth that have a small or large area at the gumline where the surface of the root is exposed. This is usually caused by brushing to hard but also can be caused by gum disease, teeth grinding, post orthodontic treatment, tooth mal position .
The tooth is composed or enamel which is only the crown of the tooth, what you normally see. There is dentin which under the enamel and cementum which makes up the root of the tooth. Dentin and Cementum are made of of microscopic tubes that lead from the outside edge to the middle of the tooth where the nerve of the tooth is.
These tubes on the outside edge usually are sealed by organic /inorganic material.
The tubes that are sealed prevent the nerve from getting stimulated. If this sealed portion of the tubules become unsealed then sensation can be transferred from the open ends right down to the nerve.
We are talking about a microscopic sealed and hard brushing, acidic foods can open the end of the tubes. The tooth will undergo opening and closing of the tubes on a constant level through out the days usually resealing the open ended tubes from chemicals in the saliva.
If the tubes remain open then cold, hot, acid will stimulate the tubes thus stimulating the nerve of the tooth causing pain.
To help stop the process it is necessary to stop the insult to the open end of the tubes. Gentler brushing, soft toothbrush, removing acidic foods and drinks, removing bacteria that produce acid can hep allow the body to re seal the tubes. This is why your teeth maybe sensitive one week and not the other.
Toothpastes such as Sensodyne and other brands have the chemicals that help seal the tubes. It requires consistent use and does not usually help until a week or two of use everyday, especially at night. We have chemicals in the dental office that can be brushed on the tooth such as high concentration of fluoride. Lasers and preventive covering over the sensitive area can also help. The tubes can always be opened up again if prevention is not consistent.