What are the most common causes of grey lines on the teeth?

Discolouration of teeth can be caused by intrinsic or extrinsic factors.

Intrinsic discolouration occurs when there are changes that occur in the internal structure of the tooth.

Common causes of intrinsic discolouration presenting as grey lines or diffused grey colours:

1. Tetracycline staining

This commonly occurs amongst patients whose mothers took tetracycline (an antibiotic) during their pregnancy, or amongst patients who consumed tetracycline when they were children (typically 0 - 8 years in age). Tetracycline deposits stain the tooth structure throughout its growth.

2. Fluorosis

This happens when the water a patient regularly drinks has fluoride concentration that exceeds 1ppm. Excessive fluoride discolours teeth and this can appear as either frosty white patches or brown-black lines.

Extrinsic discolouration is caused by 'coloured' agents or chromogens which are deposited on the tooth surface.

Common causes of extrinsic discolouration presenting as grey lines or diffused grey colours:

1. Amalgam fillings

Patients who have Amalgam fillings can sometimes experience grey discolourations of the tooth, caused by the formation of silver sulfide that is deposited from filling material.

2. Dental materials

Some dental materials used in root canal treatment such as Ledermix can cause grey pigmentation of the tooth.

3. Dental Trauma

Patients who have experienced trauma to the teeth and damage of the pulp (where nerves and blood vessels are located), will see changes in tooth colour. This particular type of grey discolouration is more diffuse.

How to treat grey lines:

Speak with your dentist to determine the cause of the grey lines on your teeth and he/she can advise the most appropriate treatment options.

Grey lines on the teeth can be due to staining(intrinsic or extrinsic), cracks in the enamel or may indicate a dead tooth(if the colour progressively worsens).

Intrinsic stains were introduced during tooth formation. These can only be corrected by renovating the teeth, placing a covering over them to hide them.

Extrinsic or surface stains should be easily removed by your dentist.

Cracks in the surface of the tooth depends on the depth. Surface cracks are quite common and if the patient finds them ugly, you can also renovate them either by composite or porcelain veneers(there is a recorded webinar on this website about Dental Veneers that you may find useful). More serious cracks may require conventional fillings or crowns. Dead teeth may require either extractions or a root canal treatment followed by a crown.