Pathophysiology and clinical features

In developed countries, dental caries (dental decay) is a common bacterial disorder. First, the surface enamel of the tooth is breached by the demineralising action of lactic acid generated by commensal oral bacteria as a byproduct of carbohydrate metabolism, particularly of refined sugar. The most vulnerable sites for decay are just below the contact points of adjacent tooth crowns and the pits and fissures on the biting (occlusal) surface of molars and premolars. These sites are inaccessible to natural oral cleansing mechanisms and to tooth brushing.

Once enamel is breached, proteolytic bacteria enter the less calcified dentine beneath and cause progressive destruction. The enamel remains intact until the dentine is undermined and the enamel fractures. Thus, dental caries may be well advanced but invisible, even to a dental mirror and probe, and detectable only on X-ray. The decay process is asymptomatic until close enough to the dental pulp to cause inflammation and pain and, eventually, bacterial invasion and abscess formation. The pathological process and corresponding symptoms are outlined in Figure 48.1.

Once the pulp is exposed, inflammation and bacterial invasion usually destroy it, then spread to the periapical region forming an abscess. This causes painful oral and facial swelling, and if untreated, eventually drains into the mouth or occasionally onto the face. However, the initiating cause, the necrotic pulp, remains, so a chronic abscess flares up intermittently or continues with a persistent discharge.

The pain of dental caries is usually well localised and recognised as a ‘toothache’. Dental pain is sometimes poorly localised and causes non-specific facial pain. In the upper jaw, this may simulate sinusitis. Dental caries should always be considered before rarer diagnoses. Overall, a surprising amount of dental caries, even with periapical infection, is asymptomatic.

Management of dental caries

Provided the dental pulp has not been invaded by infection (i.e. become ‘exposed’), a dentist can usually drill out the carious enamel and dentine and restore it (Fig. 48.2) with synthetic resin, silver amalgam or gold, with a sedative insulating lining. Once exposed, the necrotic tissue must be removed by endodontic treatment, and the pulp cavity filled; this is ‘root filling’ (Fig. 48.2). In this way, the tooth can often be preserved.

Management of dental abscesses

A periapical abscess is the most common manifestation of caries seen by general practitioners or casualty officers. Primary treatment, as for other abscesses, is drainage of pus. Extracting the offending tooth is most effective, but better to preserve the tooth by draining the abscess via the root canal then root filling it later. Patients with periapical abscesses should ideally be referred to a dentist.

Large acute abscesses ‘pointing’ within the mouth can be drained by incising at the site of greatest fluctuation. Oral penicillin should be prescribed for spreading infection. Antibiotics have no part in managing toothache unless there is swelling or other signs of an acute abscess. A dental abscess occasionally presents on the face but usually settles with extraction of the offending tooth. Dental abscesses are rarely complicated by osteomyelitis.

Bleeding tooth socket after extraction

A small amount of blood mixed with saliva may look like severe haemorrhage. The extraction site should be inspected. A normal socket should be filled with firm clot with some ooze from the gingival margin. This is aggravated if the anxious patient disturbs the clot by rinsing or ‘exploring’ the socket with the tongue. Aspirin may also promote bleeding.

Oozing or minor bleeding is easily controlled by the patient biting on a small dry pack such as a folded gauze swab and maintaining pressure for 10–15 minutes. Persistent bleeding can usually be controlled by inserting sutures through the gingival margins across the socket (Fig. 48.3) then biting on a dry gauze pad. Suturing requires local anaesthesia infiltrated into the gingiva on each side of the socket. Absorbable polyglactin sutures are preferred as they do not leave irritating sharp ends and dissolve in 5–10 days. If bleeding continues after these simple measures, the patient should be investigated for a coagulation or platelet abnormality.

Pain after tooth extraction

Forceps extraction or surgical tooth removal may lead to pain soon afterwards. Removal of lower molar teeth may cause trismus