L20. Alveolar Bone Homeostasis

The jaw is composed of the --- bone and --- bone

alveolar and basal bone

What are the components of alveolar bone?

external plate = cortical bone

inner wall socket = alveolar bone proper and cancellous bone

The external plate of alveolar bone is composed of ---

cortical bone

The inner socket wall of alveolar bone is composed of --- and ---

alveolar bone proper

cancellous bone

Alveolar bone proper is --- bone and called --- on radiographs

compact bone

called lamina dura on radiographs

What are the parts of the alveolar bone proper?

Lamellated bone

Bundle bone

The lamellae of lamellated bone are arranged ---- to the surface of adjacent marrow spaces

parallel

The bundle bone is the part of alveolar bone proper to which the --- are anchored

principal fibers of periodontal ligament

What bone forms and supports the tooth socket (alveoli)?

alveolar bone

When does the alveolar bone form?

when tooth erupts

What is the relationship of the alveolar bone and periodontal ligament?

provides bone attachment for periodontal ligament

Interdental septa

Bone between teeth

Inter-radicular septum

bone between the roots of one tooth

Thick Interdental septa is more ---- to bone resorption during inflammation

resistant

Thin Interdental septa is more ---- to bone resorption during inflammation

prone to rapid

Vertical and angular bone defects ---- in thin facial or lingual alveolar bone

DO NOT FORM

Root trunk

Area from the CEJ to the furcation

True / False: the alveolar bone gradually diminishes in size and may disappear completely after teeth are lost

true

What may help preserve the alveolar process with tooth loss?

dental implants

Periodontal ligament is composed of --- and --- connective tissues that surround the root and connect its inner wall of the alveolar bone

complex vascular and cellular connective tissue

---- are the parts of the principal fibers that are inserted into cementum and bundle bone (alveolar bone proper)

sharpey's fibers

What happens to the periodontal ligament space around teeth that are not in function?

becomes reduced

What happens to the periodontal ligament space around teeth that are subjected to hyper function?

becomes larger

What is the primary mechanoreceptor of the periodontal ligament?

ruffini nerve ending

Nociceptors are pain receptors consisting of ---

free nerve endings

True / False: the attachment of epithelium to a tooth is similar to attachment of epithelium to a dental implant

true

The oral epithelium around implants is continuous with the ---- that lines the inner surface of the gingival sulcus

sulcular epithelium

The peri-implant mucosa has --- permeability

low

The peri-implant mucosa has low permeability.

- Intercellular spaces are tightly sealed by ---

-The cells of the junctional epithelium attachment adjacent to dental implants attach to a basal lamina (basement membrane) via ---

desmosomes

hemidesmosomes

Peri-implant connective tissue morphology is similar to natural dentition but lacks

- periodontal ligament

- cementum

- inserting fibers

What is the major difference between healthy peri-implant tissues and periodontal tissues

tooth is mobile in socket

implant is rigidly anchored

How do the connective tissue fibers in an implant differ?

run in a direction parallel to implant surface

True / False: connective tissue fibers are embedded in implant surface

false = not embedded in implant surface

have cuff like orientation to create a seal around the implant

The zone of intercrestal connective tissue has an important function in the maintenance of stable soft tissue - implant interface and as a ----

seal / barrier to outside environment

Biological width

overlap of junctional epithelium and supracrestal connective tissue

What happens to the biological width / supracrestal issue attachment with implant?

Normal

- JE = 0.97 mm

- CT = 1.14 mm

Implant

- JE = 2 mm

- CT = 2 - 2.5 mm

The blood supply in the connective tissue cuff surround the implant is --- than in the gingival complex around teeth

less than

What happens to sensory function with implant insertion?

no mechanoreceptors

Occlusal forces on dental implants

Axial force

Lateral force = can result in bone loss if force exceeds the pressure the bone can withstand

Phases of wound healing following surgical periodontal therapy

Hemostasis

Inflammation

Proliferation

Remolding (maturation)

Healing outcomes following periodontal therapy

new periodontal attachment = perfect healing

long junctional epithelium = realistically

Long Bone Healing

Hematoma

Inflammation

Callus formation

Granulation Tissue

Remodeling

SAME EVENTS AS IN WOUND HEALING

What occurs in bone remodeling?

Bone resorption = removal of old bone by osteoblasts

Apposition of new bone = osteoclasts

Osseointegration

attachment of healthy bone to a metal dental implant

Stages of wound healing and osseointegration

1. Hemostasis

2. Coagulum formation

3. Bone formation

4. Bone remodeling

Stages of Wound Healing and Osseointegration

- Day 1 -3

coagulum formation

Stages of Wound Healing and Osseointegration

- Day 4

coagulum replaced with granulation tissue

contains inflammatory cells, mesenchymal cells, and newly formed vessels

Stages of Wound Healing and Osseointegration

- One week

woven bone created around vascular structures

Stages of Wound Healing and Osseointegration

- 2 weeks

woven bone deposited onto bony wall of tissue chamber and implant surface

What connects old bone and implant surface?

scaffold of tiny trabeculae of woven bone

What happens at the one to two week mark at sites where old bone is in contact with the implant surface?

process of new bone formation delayed until osteoblasts resorb old compact bone

Stages of Wound Healing and Osseointegration

- 4 weeks

chambers are filled with woven bone from old bone to implant

The volume density of the scaffold Is increased by the formation of ---- and by the deposition of more mature, parallel fibers born onto the primary scaffold

new trabeculae

Stages of Wound Healing and Osseointegration

- 6 to 12 weeks

primary bone is replaced with secondary osteons

woven bone replaced with lamellar bone and bone marrow

bone implant contact established

What is successful osseointegrated dental implant covered by?

trabecular bone or compact bone

Besides providing cushion, periodontal ligament provides --- to prevent destructive forces of the teeth

sensory function

Why is lack of sensory function with implant important to consider?

no sensory function = unable to prevent destructive forces on teeth

What cells arrive within the first 10 minutes of healing at the tooth-gingival flap interface?

red blood cells adhere to dentin

What cells arrive within an hour of healing at the tooth-gingival flap interface?

red blood cells for a fibrin network

What cells arrive within 6 hours of healing at the tooth-gingival flap interface? (early phase of inflammation)

neutrophils

What cells arrive within 3 days of healing at the tooth-gingival flap interface? (late phase of inflammation)

macrophages

lymphocytes

plasma cells

If the amount of newly formed bone is less than the amount of resorbed bone then there is a continuous ---- of bone to implant contact and --- bone implant will ----

net loss of bone to implant contact

bone implant will fail

Initial ---- is a prerequisite for osseointegration

mechanical implant stability

Initial mechanical implant stability is achieved by direct contact between bony walls of --- and surface of ---

bony walls of implants bed and surface of dental implants

Primarily implant stability is ---

mechanical

Secondary implant stability is ---

biological

Secondary stability of dental implants is established by the ---- of --- onto implant surface

apposition of new bone

The bonding between new bone and the implant is --- in nature

biological

True / False: new bone apposition begins earlier in regions of trabecular bone than in compact bone

true

Relationship of primary and secondary implants stability

primary stability decreases over time

secondary stability increases over time

A ---- in implant stability occurs 3-4 weeks after placement

transient decrease

Compartmentalization

wound closure