Oral Biology & Pathology Flashcards

What is the mechanism of action of fluoride in preventing dental caries?

Answer: Fluoride incorporates into hydroxyapatite to form fluorapatite (more acid-resistant); enhances remineralisation; inhibits bacterial enzymes

Fluoride's anti-caries effect is multi-factorial: (1) substitution into hydroxyapatite forming fluorapatite (acid-resistant), (2) enhancing remineralisation post-acid attack, and (3) inhibiting bacterial enolase enzymes reducing acid production.

What is a 'radicular cyst' (periapical cyst) and what stimulates its formation?

Answer: An inflammatory odontogenic cyst arising from the rests of Malassez, stimulated by inflammatory mediators from a non-vital infected tooth

The radicular (periapical) cyst is the most common odontogenic cyst overall. It develops from epithelial rests of Malassez in the PDL, stimulated to proliferate by inflammatory mediators from pulp infection/necrosis.

What is the significance of 'dark zones' in enamel caries histology?

Answer: Dark zones contain small pores filled with organic material and represent an area of remineralisation activity at the advancing front of early caries

In the histology of early enamel caries, the dark zone (beneath the translucent zone at the lesion front) shows small pores with remineralisation activity — it is a zone of repair. This underpins the concept of treating early lesions by remineralisation.

What is 'amelogenesis imperfecta'?

Answer: A hereditary condition affecting enamel formation causing hypoplasia, hypomineralisation, or hypomaturation — teeth affected throughout the dentition in both dentitions

Amelogenesis imperfecta (AI) is a group of hereditary conditions affecting enamel formation genes (AMELX, ENAM, MMP20 etc.). It causes enamel defects ranging from hypoplasia (thin) to hypomineralisation (soft/discoloured) affecting all teeth.

What cells initiate the inflammatory response in gingivitis?

Answer: Neutrophils and lymphocytes responding to bacterial biofilm products at the gingival margin

Early gingivitis is characterised by neutrophil migration from the junctional epithelium vasculature in response to bacterial LPS and other virulence factors. Lymphocytes (T cells) accumulate in the established lesion.

What is 'denture stomatitis' and what is its most common cause?

Answer: Erythematous mucositis under a denture, most commonly caused by Candida albicans overgrowth facilitated by continuous denture wear and poor denture hygiene

Denture stomatitis (Newton type I–III) is erythema under an upper denture, predominantly caused by Candida albicans overgrowth. Risk factors include continuous wear, poor denture hygiene, and dry mouth.