Endodontics

Diseases of Dental Hard-Tissues and Pulp

Dental-hard-tissue disorders are known as dental diseases. In a broad sense, endodontic (pulp) diseases are also included.

Dental caries is a progressive lesion of tooth hard-tissues caused by multiple oral factors. It is characterized by demineralization of inorganic components and decomposition of organic matrix. The lesion evolves from discoloration of enamel to substantial structural defects. The World Health Organization ranks dental caries together with cancer and cardiovascular diseases as the three major global diseases requiring priority prevention and treatment.

Etiology of pulp diseases

1. Microbial infection

Bacteria are the most significant causative agents of pulp diseases. Routes of bacterial invasion:

1. Infection via tooth defects: Deep caries, dental trauma, severe attrition and other hard-tissue damage allow bacteria and toxins to penetrate the pulp through dentinal tubules or pulp exposures.

2. Periodontal-route infection: Bacteria and toxins travel through periodontal pockets, apical foramina and lateral canals to invade the dental pulp.

3. Hematogenous infection: Pulp invasion by bacteria via the bloodstream is extremely rare but possible.

2. Chemical irritation

1. Medicament irritation: Disinfectants such as phenolic agents applied after cavity preparation may irritate the pulp.

2. Restorative-material irritation: Direct placement of zinc-phosphate cement in deep cavities or direct composite-resin filling may cause pulp irritation.

3. Physical irritation

1. Thermal stimulation: Water-cooling is mandatory when high-speed air-turbine handpieces are used during cavity preparation. Without cooling, pulp hyperaemia, haemorrhage and subsequent inflammation may occur.

2. Galvanic current stimulation: When two dissimilar metallic restorations make contact in the mouth, saliva can generate a galvanic potential that irritates the pulp.

3. Barometric-pressure changes: Sharp-pressure variations during high-altitude flight or deep-sea diving can trigger acute exacerbation of pre-existing pulp conditions.

4. Trauma: Mechanical injury to teeth may lead to pulp degeneration.

4. Systemic factors

Systemic conditions such as diabetes mellitus can induce pulp degeneration. Tumours may also involve the dental pulp. True haematogenous pulp infection is very uncommon in clinical practice.