The course of a periodontal disease
Deposits build up and a mild gum inflammation arises from plaque and calculus.
The gum becomes inflamed; it bleeds. Deposits build up on the tooth at the gum margin, and plaque and calculus give rise to a mild inflammation of the gum – gingivitis.
The gum margin detaches from the tooth, bacteria spread, plaque hardens into calculus and the surrounding bone breaks down. The result is a severe inflammation of the gum and the periodontium – periodontitis.
The gum recedes, jawbone and retaining fibres break down further, and a bony defect forms. The tooth becomes loose and falls out.
Recession
If periodontitis goes untreated, the inflammation works its way deeper along the root. Bony defects arise – the bone is broken down and the gum follows. Where this exposes the neck of the tooth, it is called a recession defect.
Possible without inflammation too
Gum and bone can also recede without any preceding inflammation. The reasons vary: brushing too hard with a stiff brush, an unfavourable tooth position, a tight lip frenulum pulling at the gum, or naturally thin tissue.
The distinction matters, because treatment differs: with inflammation that has to heal first; with a mechanical cause the cause is addressed first.