Introduction
This topic covers the common inflammatory diseases of the teeth and their supporting tissues: dental caries, pulpitis, periodontitis (inflammation around the root apex), the radicular cyst that may follow it, and periodontal disease (gingivitis and marginal periodontitis). These conditions form a chain: caries leads to pulpitis, then apical periodontitis, abscess or cyst.
Dental caries
Caries is progressive, localized destruction of the hard dental tissues (enamel, dentine, cementum) by acids produced by bacteria. It is the commonest chronic disease of the teeth.
- Etiology: plaque bacteria, mainly Streptococcus mutans and lactobacilli, ferment dietary sugars to lactic acid; the pH falls and demineralization follows. Contributing factors are a high-sugar diet, poor hygiene, reduced saliva, low fluoride, tooth shape (fissures) and crowding.
- Stages: (1) white spot (macula): a chalky, demineralized area under intact enamel; (2) superficial caries: a defect in the enamel; (3) medium caries: spread into the dentine; (4) deep caries: a deep cavity close to the pulp. In dentine, caries spreads along the tubules and is wider than at the surface, so the enamel may undermine.
- Morphology: decalcified, softened, brown-pigmented tissue; microscopically a zone of destruction with bacteria in the tubules, a zone of demineralization, and a deeper zone of sclerosis of the tubules and reparative (tertiary) dentine formed by odontoblasts.
- Forms: pit and fissure caries, smooth-surface and interproximal caries, root (cementum) caries in the elderly with gum recession, and rampant caries (early childhood, bottle caries).