Alveolar Bone Homeostasis

Question 1

The jaw bone is comprised of

Answer 1

Alveolar bone (forms tooth sockets)
Basal bone (supportive foundation)

Question 2

Alveolar Bone (Structure) is composed of

Answer 2

• External plate: compact cortical bone (Haversian/lamellar)
• Alveolar bone proper: dense bone lining the socket; seen as the lamina dura on X-rays
• Cancellous bone: trabecular bone between compact layers

Question 3

what is the function an formation of the Alveolar Bone?

Answer 3

• Forms when teeth erupt
• Supports the tooth socket (alveoli)
• Anchors the periodontal ligament

Question 4

what is the lamina dura?

Answer 4

Appears as a white radiopaque line around tooth roots on radiographs and represents the dense bundle bone of the alveolar bone proper.

Question 5

what are the factors that affect Alveolar Bone Morphology?

Answer 5

Alignment & proximity of teeth
Root/root trunk anatomy
Root position in alveolar process

Question 6

how does root trunk anatomy affect the alveolar bone?

Answer 6

the shape and length of the root trunk (the part of the root before it branches) affects furcation exposure and periodontal prognosis
- longer root trunks = better prognosis; short trunks expose furcations more quickly.

Question 7

how does root position within the alveolar process affect the bone?

Answer 7

normally the root is centrally embedded but misalignment or buccal/labial positioning can increase the risk of bone dehiscence and gingival recession

Question 8

what are the anatomical factors that determine Alveolar Bone Morphology?

Answer 8

• thickness/width of interdental bone
• thickness/width of facial/lingual alveolar plate
• tooth alignment
• root anatomy
• fenestration/dehiscence presence

Question 9

how does thickness and width of the interdental septa affect bone support?

Answer 9

Narrow septa are more prone to vertical bone loss
**Thin interdental bone → vertical bone loss

Question 10

how does the thickness of the facial and lingual Alveolar Plate affect bone support?

Answer 10

• Thin plates = horizontal bone loss
• Thicker plates = support vertical/angled defects
  **Thin bone more vulnerable to resorption

Question 11

how does root position & presence of fenestration and dehiscence affect the bone?

Answer 11

Fenestrations are window-like bone loss and dehiscence is bone loss that extends to alveolar crest which is common in facially-positioned teeth.
***Leads to gingival recession and potential implant complications

Question 12

what happens to alveolar bone after a tooth is lost?

Answer 12

Alveolar bone requires mechanical stimulation to maintain volume so after tooth loss, bone gradually resorbs and may disappear completely, complicating implant placement or prosthetics.

Question 13

What are the main components of the periodontium?

Answer 13

gingiva, cementum, periodontal ligament (PDL), and alveolar bone that support and anchor the tooth

Question 14

What is the periodontal ligament and what does it connect?

Answer 14

a complex, vascular, highly cellular connective tissue that surrounds the tooth root and connects it to the alveolar bone

Question 15

What are the two main components of the alveolar bone proper?

Answer 15

• lamellated bone (with circumferential, concentric, and interstitial lamellae)
• bundle bone where PDL fibers insert

Question 16

What is the function of bundle bone in the alveolar process?

Answer 16

anchors the principal fibers of the PDL and appears as the lamina dura on radiographs

Question 17

What are Sharpey’s fibers and where do they insert?

Answer 17

parts of PDL fibers that insert into the cementum and bundle bone, securing the tooth in its socket

Question 18

What cellular elements are found in the periodontium?

Answer 18

fibroblasts, cementoblasts, cementocytes, osteoblasts, and odontoblasts; these cells help form and maintain supporting structures

Question 19

How does PDL space differ with function?

Answer 19

space is reduced in non-functioning teeth and increased in teeth under hyperfunction (excess force)

Question 20

What nerve receptors are found in the PDL?

Answer 20

Ruffini endings (mechanoreceptors) and nociceptors (pain receptors made of free nerve endings)

Question 21

What is the implant-epithelium interface and how is it similar to natural teeth?

Answer 21

Like teeth, the implant-epithelium interface has oral epithelium continuous with sulcular epithelium and the apical sulcus is lined with long junctional epithelium, forming a seal against the implant

Question 22

How does the sulcular epithelium attach around dental implants?

Answer 22

The peri-implant mucosa has low permeability and intercellular spaces are sealed with desmosomes, and junctional epithelial cells attach to the basal lamina with hemidesmosomes

Question 23

What supporting tissues are not found around dental implants?

Answer 23

Although similar to natural dentition, peri-implant connective tissue lacks:
- Periodontal ligament
- Cementum
- Inserting fibers

Question 24

What are key differences between peri-implant and periodontal tissues?

Answer 24

Implants lack root cementum, PDL, and alveolar bone proper.
- Teeth are mobile in sockets.
- Implants are rigidly ankylosed to bone
- Fiber bundles that anchor soft tissue to cementum (like dentogingival fibers) are absent in peri-implant tissues

Question 25

How do connective tissue fibers differ between implants and natural teeth?

Answer 25

in implants - CT fibers are oriented parallel to the implant surface, not embedded - They differ from perpendicular Sharpey’s fibers in teeth - Some fibers form a cuff-like circle, helping create a soft tissue seal.

Question 26

What is the role of supracrestal connective tissue around implants?

Answer 26

It maintains a stable tissue–implant interface and acts as a seal protecting the inner implant area from the outside oral environment

Question 27

What makes up the supracrestal tissue attachment (biologic width) around implants and natural teeth?

Answer 27

Supracrestal tissue attachment includes: - Junctional epithelium (JE): ~2 mm in implants or 0.97mm in natural teeth - Connective tissue (CT): 2.0-2.5 mm in implants or 1.07 in natural teeth - Total biologic width: ~4-4.5 mm around implants, ~2.04 mm around natural teeth

Question 28

How does vascular supply differ between implants and natural teeth?

Answer 28

The connective tissue around implants has less blood supply than the gingival complex around teeth, this reduced vascularity may impact healing and immune defense

Question 29

What is the sensory difference between teeth and implants?

Answer 29

- Teeth have PDL mechanoreceptors that provide precise sensory feedback - Implants lack PDL, so they do not have mechanoreceptors, making them less sensitive to occlusal force

Question 30

How do occlusal forces affect teeth vs. implants?

Answer 30

- Axial force (vertical): Better tolerated by both - Non-axial force (horizontal): More damaging, especially to implants due to lack of PDL cushioning and adaptation and can cause bone loss or implant failure

Question 31

What are the four phases of wound healing following periodontal therapy?

Answer 31

1. Hemostasis (Clot formation) 2. Inflammation (Granulation tissue/matrix formation) 3. Proliferation (Tissue formation/repair) 4. Maturation (Remodeling) Each phase overlaps with the others over time

Question 32

What cellular events occur early at the tooth-gingival flap interface post-surgery?

Answer 32

- 10 min: RBCs adhere to dentin - 1 hr: RBCs in fibrin network - 6 hr: Early inflammation - 3 days: Late inflammation - 5-7 days: Granulation then connective tissue formation

Question 33

What are the visual stages of wound healing after periodontal treatment?

Answer 33

Healing progresses from initial surgical trauma, to tissue inflammation, to granulation tissue formation, and finally to regeneration or repair

Question 34

What are the two healing outcomes following periodontal therapy?

Answer 34

- New periodontal attachment (ideal outcome) - Long junctional epithelium (repair rather than true regeneration)

Question 35

How does wound healing differ between long bones and alveolar bone?

Answer 35

Both go through inflammation, proliferation (angiogenesis, MSC recruitment), and remodeling, but alveolar bone has faster turnover and is more affected by surrounding soft tissue and oral environment

Question 36

What are the stages of long bone wound healing?

Answer 36

1. Inflammation 2. Cell proliferation (MSC and endothelial cells) 3. Angiogenesis 4. Differentiation 5. Bone formation (woven to lamellar) 6. Remodeling

Question 37

What is bone remodeling and why is it important?

Answer 37

Continuous process of bone resorption and apposition of new bone and maintains bone structure and integrity

Question 38

Why is bone remodeling critical for alveolar bone maintenance?

Answer 38

Growth Calcium balance Tooth eruption/migration Orthodontic movement Wound healing

Question 39

What is osseointegration ?

Answer 39

the direct functional and structural connection between living bone and the surface of a load-carrying implant

Question 40

What are the stages of wound healing and osseointegration?

Answer 40

1. Hemostasis and coagulum formation 2. Granulation tissue formation 3. Bone formation 4. Bone remodeling

Question 41

What happens between days 1-4 in implant wound healing?

Answer 41

Day 1: Coagulum forms Day 4: Coagulum is replaced by granulation tissue with inflammatory cells, mesenchymal cells, and new blood vessels

Question 42

What occurs around 1 week post-implant placement?

Answer 42

Woven bone begins forming as fingerlike projections around vascular structures and contacts small implant areas

Question 43

What changes are seen by 2 weeks after implant placement?

Answer 43

Woven bone is deposited on bone walls and implant surface. A scaffold of woven bone connects the implant to old bone.

Question 44

Why is bone formation delayed at sites with compact old bone (1-2 weeks)

Answer 44

Bone formation is delayed because compact old bone must be resorbed first by osteoclasts to allow remodeling

Question 45

What is the significance of the Berglundh Wound Healing Chamber Model?

Answer 45

It illustrates the spatial and temporal process of osseointegration, showing bone growth and tissue adaptation within a controlled chamber around an implant

Question 46

What happens in the alveolar bone at 4 weeks post-implant placement?

Answer 46

- Woven bone fills chambers, extending from old bone to the implant surface. - More trabeculae form, increasing scaffold volume. - Mature, parallel-fibered bone is deposited on the scaffold.

Question 47

What key changes occur in bone between 6–12 weeks after implant placement?

Answer 47

- Bone remodeling replaces primary woven bone with secondary osteons. - Woven bone becomes lamellar bone and bone marrow. - Bone-to-implant contact is established.

Question 48

What defines a successfully osseointegrated dental implant?

Answer 48

- The implant is surrounded by either compact or trabecular bone. - Indicates direct bone-to-implant contact with no intervening soft tissue.

Question 49

What are the steps and concerns of bone remodeling after implant placement?

Answer 49

- Continuous resorption and apposition of bone If new bone formation is less than bone resorption, it risks: - Loss of bone-implant contact - Failed osseointegration - Implant failure

Question 50

What mechanical factors influence osseointegration of an implant?

Answer 50

Primary mechanical stability is required and depends on: - Direct contact between implant surface and bony walls - Mechanical, not biological bonding

Question 51

What defines primary vs. secondary implant stability?

Answer 51

- Primary stability: Mechanical (initial placement) - Secondary stability: Biological (bone healing and remodeling)

Question 52

What factors determine primary implant stability?

Answer 52

- % of bone-to-implant contact - Implant design: diameter, length, thread architecture - Vertical sink depth relative to bone crest - Implant surface roughness (micro/nanotopography) - Local bone quality—compact bone is better than trabecular

Question 53

What is secondary stability of dental implants and how is it achieved?

Answer 53

Secondary stability is established by the apposition of new bone onto the implant surface, it involves biological bonding and occurs earlier in trabecular bone than compact bone where surface roughness (micro-/nanotopography) also contributes.

Question 54

How does primary and secondary implant stability relate over time?

Answer 54

Primary stability decreases, and secondary stability increases over time - Their combined contribution determines total implant stability

Question 55

What causes a transient decrease in implant stability, and when does it occur?

Answer 55

A temporary dip in implant stability occurs at 3–4 weeks post-placement due to a transition between mechanical and biological stability phases.

Question 56

What helps achieve higher and more stable implant stability long-term?

Answer 56

Having both cortical and trabecular bone around the implant provides better initial and long-term stability, reducing the dip in stability.

Question 57

What are the key factors for successful alveolar bone regeneration around teeth and implants?

Answer 57

elimination of infection, hemostasis, space provision, wound closure, surgical technique, and innate healing potential—dependent on cell type availability and cell signaling for regeneration.