ABP Periodontal Pathogenesis and Host Response 3

Question 1

The 'ecological plaque hypothesis' (Marsh, 1994) proposes that periodontal disease is caused by:

Accepted Answer

Environmental shifts in the subgingival niche that select for a dysbiotic, disease-promoting microbiome

Answer

The ecological plaque hypothesis holds that disease-associated bacteria are present in health but environmental changes (inflammation, anaerobiosis, nutrient availability) select for their overgrowth, transitioning health-compatible communities to dysbiotic ones.

Question 2

In Page and Schroeder's histopathological stages of the periodontal lesion, the 'established lesion' is characterized by predominance of:

Accepted Answer

Plasma cells and B lymphocytes with possible pocket formation

Answer

The established lesion (corresponding to chronic gingivitis) is dominated by plasma cells secreting immunoglobulins and B lymphocytes; importantly, the lesion is not yet destructive — that distinguishes the advanced lesion.

Question 3

The IL-1 gene cluster polymorphism (composite genotype +) is clinically significant in periodontology because carriers demonstrate:

Accepted Answer

Elevated IL-1α and IL-1β production, increasing susceptibility to severe periodontitis

Answer

The IL-1 composite genotype (polymorphisms at IL-1A +4845 and IL-1B +3954) results in hyper-secretion of IL-1α and IL-1β, which drives exaggerated RANKL-mediated bone resorption and increases periodontitis risk — especially in smokers.

Question 4

Epigenetic modifications implicated in periodontal pathogenesis alter gene expression WITHOUT changing the DNA nucleotide sequence through mechanisms such as:

Accepted Answer

DNA methylation, histone modification, and microRNA regulation

Answer

Epigenetic mechanisms — CpG methylation silencing anti-inflammatory genes, histone acetylation/deacetylation regulating cytokine expression, and microRNAs controlling post-transcriptional output — all contribute to the persistent pro-inflammatory phenotype seen in periodontitis.

Question 5

In response to bacterial challenge in periodontitis, the junctional epithelium undergoes which critical pathological change?

Accepted Answer

Conversion to pocket epithelium and apical migration along the root surface

Answer

Bacterial products and inflammatory mediators cause junctional epithelium proliferation, ulceration, and apical migration, converting it to a non-adherent pocket epithelium with increased permeability that deepens the sulcus into a true periodontal pocket.

(ABP) American Board of Periodontology Practice Test

(ABP) American Board of Periodontology Practice Test

ABP Periodontal Pathogenesis and Host Response 3