Periapical infection with Streptococci & Staphylococci
Majority of streptococci produce hyaluronidase, an enzyme that dissolves hyaluronic acid which is a universal intercellular cementing substance. It helps in the spread of infection. Usually staphylococci are good producers of hyaluronidase, so there is no spread of infection and the infection becomes localised in the form of abscess in case of staph infection.
Streptococci are also producers of fibrinolysin that dissolves fibrin. Along With Hyaluronidase, it causes the spread of infection into tissue spaces resulting in cellulitis.
A dental abscess may develop directly from in a necrotic pulp or often it originates in an area of chronic infection e. g. periapical granuloma.
Ludwig angina is the advanced stage of cellulitis. It usually begins in the submaxillary space and later involves the sublingual and submental spaces. The main source of infection is second and third molars. Most cases show mixed infection and streptococci are invariably present.
In Ludwig Angina, if 2nd premolar and 1st molar are involved then sublingual space is involved primarily as their apices lie above the mylohyoid attachment level. On the contrary, if 2nd and third molars are involved, submaxillary space primarily gets involved as their apices lie below mylohyoid attachment level.
In acute osteomyelitis little or no radiographic features are seen for at least one or two weeks. Later, diffuse lytic changes in the bone begins to appear. individual trabeculae becomes hazy and indistinct. Radiolucent area begins to appear. In earlier stages of chronic osteomyelitis mottled appearance is seen in radiographs. In established cases of osteomyelitis moth eaten appearance is seen because of enlargement of medullary spaces and widening of Volkmann’s canal.
The most common organism cultured from the osteomyelitis lesions include staphylococcus aureus and staphylococcus Albus.
Chronic hyperplastic pulpitis
Chronic hyperplastic pulpitis is due to excessive exuberant proliferation of chronically inflamed pulp tissue. It occurs exclusively in children and young adults and commonly involves large open carious lesions. The teeth most commonly involved are a deciduous molar and first permanent molars as they have an excellent blood supply because of their large root opening. The high tissue resistance and reactivity in young persons accounts for the unusual proliferation property of the pulp tissue.
The cells of periapical granuloma which are predominantly lymphocytes increase by division at the periphery and the cells in the centre are separated from their source of nutrition; hence degenerate and liquify. This results in an epithelium lined cavity filled with fluid known as periapical cyst.
In condensing osteitis the periodontal ligament space is widened and this is an important feature in distinguishing from cementoblastoma.
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