Oral bio CA2

Oral Mucosa & Epithelium

1. Which areas of the oral mucosa have keratinized vs. non-keratinized epithelium?

- Keratinized: Hard palate, gingiva (attached gingiva), dorsal tongue (filiform papillae).

- Non-keratinized: Soft palate, buccal mucosa, floor of mouth, ventral tongue, sulcular epithelium.

2. Difference between keratinized and non-keratinized epithelium?

- Keratinized: Has a granular layer (stratum granulosum), superficial keratinized layer (stratum corneum), and no nuclei in outer layers.

- Non-keratinized: No granular layer, cells retain nuclei in outer layers, matures faster.

3. What protein is very important to epithelium?

- Cytokeratin (intermediate filaments provide structural support).

4. What is the first fiber to form in connective tissue?

- Collagen fibers (type I) form first; elastic fibers develop later.

5. What gives gingiva its color?

- Vascularity (blood supply) + melanin pigmentation + thickness of epithelium.

6. Which layer contains progenitor/immature cells?

- Basal layer (stratum basale) – contains stem cells that divide and differentiate.

7. Desmosome vs. hemidesmosome (electron microscope)?

- Desmosome: Connects epithelial cells to each other.

- Hemidesmosome: Anchors epithelial cells to the basement membrane.

Oral Structures & Features

8. Why is there stippling in periosteum?

- Due to collagen fiber bundles inserting into the bone (creates an uneven surface).

9. Are sebaceous glands in oral epithelium normal?

- No, they are ectopic (e.g., Fordyce granules).

10. Where are taste buds located?

- Tongue (fungiform, circumvallate papillae), soft palate, pharynx, epiglottis.

11. Which tongue areas detect tastes?

- Tip: Sweet/salty. Sides: Sour. Posterior (circumvallate): Bitter. Umami: Widespread.

12. Innervation of anterior vs. posterior 1/3 of tongue?

- Anterior 2/3: Lingual nerve (V3) → taste via chorda tympani (VII).

- Posterior 1/3: Glossopharyngeal (IX).

13. What is the vermillion zone?

- The red border of lips (thin keratinized epithelium with high vascularity).

14. Difference between skin and oral mucosa?

- Skin: Thick, keratinized, hair, sweat/sebaceous glands.

- Oral mucosa: Thinner, non-keratinized (mostly), no hair, minor salivary glands.

15. Where is the thinnest epithelium?

- Floor of the mouth (non-keratinized).

16. Hardest oral mucosa area?

- Masticatory mucosa (gingiva, hard palate – heavily keratinized).

Tooth Development & Histology

17. Junctional epithelium attaches via?

- Hemidesmosomes (tooth surface) + basal lamina.

18. Cells forming enamel, dentin, cementum, pulp?

- Enamel: Ameloblasts. Dentin: Odontoblasts. Cementum: Cementoblasts. Pulp: Fibroblasts.

19. How many dentin tubules does 1 ameloblast induce?

- 1 ameloblast induces 1 dentin tubule (one-to-one relationship).

20. Main collagen type in dental structures?

- Type I collagen (bone, dentin, cementum, PDL).

21. HERS becomes what?

- Cell rests of Malassez (epithelial remnants in PDL).

22. Cementum types?

- Acellular: Near CEJ (first formed). Cellular: Apical (contains cementocytes).

23. Majority of pulp cells?

- Fibroblasts (produce collagen).

24. Cementum-enamel junction (CEJ) variations?

- 60%: Cementum overlaps enamel. 30%: Edge-to-edge. 10%: Gap.

25. Most accepted root development theory?

- HERS (Hertwig’s Epithelial Root Sheath) guides root shape.

Bone & Mineralization

26. Bone-forming cells?

- Osteoblasts (build bone). Osteoclasts (resorb bone; influenced by PTH).

27. Hormone affecting osteoclasts?

- Parathyroid hormone (PTH) ↑ osteoclast activity (↓ blood calcium).

28. Mandibular anterior bone thickness?

- Thin (risk of perforation during implants).

29. Normal serum calcium/phosphate levels?

- Calcium: 8.5–10.5 mg/dL. Phosphate: 2.5–4.5 mg/dL.

30. What aids/inhibits calcium absorption?

- Aids: Vitamin D, acidic pH. Inhibits: Phytates, oxalates, high fiber.

31. Hormonal deficiency causing enamel hypomineralization?

- Vitamin D deficiency (rickets).

Dentin and enamel

32. Interglobular dentin is hypo- or hypermineralized?

- Hypomineralized (areas where globules didn’t fuse).

33. Tertiary dentin forms when?

- After trauma/inflammation (reactionary/reparative).

34. Mantle dentin location?

- Nearest to DEJ (first-formed dentin).

35. Enamel rods vs. interrod enamel?

- Rods: Hypermineralized. Interrod: Less mineralized.

36. Surface enamel vs. near DEJ?

- Surface: More mineralized, fewer rods. DEJ: Less mineralized, scalloped.

37. Amelogenin function?

- Major enamel matrix protein (guides mineralization).

Eruption & Shedding

38. Gubernacular cord role?

- Guides permanent tooth eruption (contains osteoclasts).

39. Phases of eruption?

- Pre-eruptive, eruptive, post-eruptive.

40. Cells for bone/cementum formation/removal?

- Formation: Osteoblasts, cementoblasts. Removal: Osteoclasts.