Fibroepithelial polyp is a swelling of gum tissue in the mouth, often caused by trauma.

Files These are instruments used in root canal treatment. They widen and clean the root canals prior to the root filling being placed.

Fillings There are many types of filling material, the commonest being amalgam, composite and glass ionomer. Most fillings require the anaesthesia of the tooth which is being restored. Fillings are named according to the surfaces of the teeth involved. Surfaces include -  Mesial - furthest front, Distal - furthest back, Occlusal -biting surface of back teeth, Palatal - next to roof of mouth, Lingual - next to tongue, Labial - next to lip, Buccal - next to cheek, Incisal - biting or incising surface of front teeth. If one or more surface is involved an abbreviation may be used e.g a M.O.D amalgam would mean that the mesial, occlusal and distal surfaces of the tooth were being restored.

Fissure The grooves on the occlusal or biting surface of back teeth.

Fissure caries Commonly decay will begin in the fissures of teeth as plaque may become trapped in deep grooves.

Fissure (& pit) sealant A preventative resin based material applied to pits and fissures of the occlusal surface of teeth to render them less plaque retentive. Cured (hardened)  with light cure. 

Flap A section of gum raised in order that a surgical procedure may be carried out. Will require sutures following the minor operation.

Floss A waxed or unwaxed piece of nylon string that is inserted between the teeth to remove debris and plaque. see flossing

Flossing- Take 30-40 cm of floss and wrap around the middle finger of each hand. Pull the floss tightly between the fingers and using the thumbs and index fingers  gently slide the floss between two teeth. Curve the floss around each surface of the two teeth in turn moving it between the tooth and gums as far as it will comfortably go under the gumline. Waxed floss is often easier for first time users. Ask your dentist or hygienist to demonstrate this technique if you are having problems.

Fluoride A chemical which strengthens the teeth. It can be found naturally in the water supplies of certain areas and is added to others. Unfortunately, in places like Scotland there is no or little fluoride in the water supply. Fluoride is also found in most toothpastes and may be given as supplements to children to help strengthen developing teeth. Ask your dentist if (s)he would recommend such supplements for your family.

Fluorosis This is a condition caused by ingestion of large quantities of fluoride, either on one occasion or over a prolonged period. It results in the discolouration of the teeth, with brown and/or white mottled marks. In most cases these marks may be reduced or removed with a process called micro-abrasion.

Forceps These are the instruments used to remove teeth.

Fungal infections see candidiasis.

Furcation lesions occur in multi-rooted teeth where periodontitis has exposed the area where roots diverge. These can be graded as 1,2 or 3 depending upon severity.