Periodontics · single question
Where in the oral cavity does biofilm show the GREATEST microbial diversity?
Show answer and explanation
Correct answer: A. Interproximal (approximal) areas
Interproximal (approximal) areas harbor the greatest microbial diversity in the oral biofilm. These protected niches have limited salivary flow, oxygen tension varies (creating both aerobic and anaerobic microenvironments), and they are difficult to clean. This environment supports a complex consortium of early, bridging, and late colonizers. Subgingival biofilm in these regions is the primary driver of both caries (interproximal) and periodontal disease.
- A. ✅ CORRECT – Interproximal areas have the greatest biofilm diversity due to protected microenvironment with varied oxygen levels and limited cleansing.
- B. ❌ The buccal mucosa has relatively sparse, simple biofilm due to mechanical cleansing by the cheek.
- C. ❌ The palate is exposed to saliva flow and tongue contact — less conducive to complex biofilm development.
- D. ❌ The dorsal tongue has high diversity but more aerobic/facultative species; the interproximal areas harbor more complex anaerobic biofilm.