Editors

LeoTjäderhane

Dental Caries and other Diseases of the Hard Tissues of the Teeth and Dental Pulp

If left untreated, dental caries leads to an inflammation of the dental pulp tissue and of the bone surrounding the tooth.
Dental caries and wearing of teeth may lead to imbalanced functioning of the masticatory system, which may cause symptoms also outside of the mouth, in the area of the face and head.
Treatment of more extensive damage caused by dental caries or wearing of teeth may require comprehensive care broader than regular restorative therapy.

Caries is the most common disease of the hard dental tissues. While the incidence of caries in children and adolescents is relatively low in countries like Finland with systematically organized dental care, its prevalence has however remained high and has at the same time shifted to the older population.
The first stage of caries is the accumulation of bacteria of the normal oral flora on the hard dental tissue surfaces and the formation of so-called dental plaque. Therefore, the best preventive measure is regular brushing of the teeth with a fluoridated toothpaste.
The first locations of carious attack are the occlusal fissures and fossae of molar teeth, then the interproximal surfaces of the teeth and finally the gingival margin area. The development of caries in the gingival margin area happens usually more slowly, but in persons with reduced salivary flow, it may also develop and progress even very rapidly.
The first sign of carious attack on the enamel surface is the disappearance of the shine of the tooth. Rapidly progressing dental caries is white in colour. When the carious attack is slow or its progression has stopped, the carious area can be distinguished by its brownish or even black discolouration (picture 1).
Because the hard dental tissues lack blood circulation, mechanical removal is the only way to destroy the bacterial invasion. The removed tissue is then replaced with a filling material.

Pulpitis is the inflammation of dental pulp due to the invasion of microbial toxins into the pulp.
When bacteria themselves invade the pulpal cavity, it results in necrosis of the pulpal tissue.
Microbes invading deeper into the dental pulp, together with the tissue remnants of the necrotic pulp induce an inflammatory reaction around the tooth root apex. This results in bone loss when the bone at the apex is reached and further in an acute apical periodontitis. If left untreated this may lead to acute infection, periapical abscess formation and intraoral or extraoral swelling. Without treatment the condition becomes chronic and may lead to intraoral or extraoral fistula formation.
Acute infection is often associated with aching pain that can be severe. The patient may sometimes also have general symptoms of infection.
The treatment of all these diseases is endodontal removal of the necrotic pulp tissue and infected dentin around the pulp cavum and replacement by a root filling material. In the case of an acute abscess the inflammatory exudate is removed by incision or by removing the tooth. Antimicrobial medication is prescribed as needed. In some cases removal of the necrotic pulp material also requires extraction of the whole tooth.

Wear of the teeth may be caused by attrition, abrasion or erosion. Often these occur simultaneously. For the treatment to be successful it is essential to find out the cause of pathological dental wear.
Pathological dental wear may lead to more extensive disorders of the masticatory system, e.g. degenerative changes and pain in the temporomandibular joint.

Wearing of the tooth material due to grinding of the teeth against each other (picture 2).
Seen on occlusal surfaces as well as on interproximal surfaces of teeth.
It is classified as a disease only in excessive cases when the wearing exceeds the so-called physiological attrition.
The reason for pathological attrition might be an imbalanced occlusion of the dentition, teeth grinding, especially during night-time (bruxism) and dentofacial anomalies.

Wearing of the tooth caused by an external material (picture 3).
The reasons might be, for example, dentifrice, tooth brushes, or too agressive tooth brushing in general.
Even tooth-restoration materials of a wrong type might be a reason for abrasion of the opposite tooth.

Erosion means the chemical dissolution of tooth material by acids that are not produced by the dental plaque micro-organisms.
The first sign of erosion is the disappearance of the shine on the tooth surface. Thereafter the process leads to the disappearance of enamel minerals (picture 4).
Erosion normally starts on the lingual side of the upper incisors, resulting in very thin enamel on the incisal edge that leads to enamel fractures. This results in a rugged incisor edge and shortening of the crowns.
Reasons
- The most common external causes include drinking of acidic drinks (e.g. sport drinks,) and a vegetarian diet.
- The most important internal reason is heartburn or gastro-oesophagial reflux (GER) resulting in gastric acid reflux into the oral cavity.
- Erosion of teeth has significance in the diagnosis of persistent regurgitation in cases of bulimia and anorexia nervosa, because these patients are often reluctant to reveal vomiting.

If only an individual tooth is affected, the eroded tooth material can be replaced with a restoration material. If the erosion is extensive, even several teeth may have to be crowned.