exam 2 (L3) - postsurgical wound healing

Question 1

what are the 3 phases of post-surgical wound healing?

Answer 1

• inflammation (and clotting)
• fibroblastic granulation
• matrix formation and remodeling

Question 2

what is healing by primary intention?

Answer 2

wound edges are brought together, and held together by sutures; heals fast

Question 3

what is the immediate wound healing response?

Answer 3

• blood clot forms b/w adjacent wound margins; also clotting b/w flap and the tooth/bone
• clot contains: fibrin, PMN, platelets, RBC, debris
• capillaries present at wound margins

Question 4

what happens in the first 24 hours of wound healing?

Answer 4

• PMN infiltrate CT

- epithelium begins migration from wound margins

Question 5

what happens in the first 1 - 3 days of wound healing?

Answer 5

• space b/w flap and tooth/bone narrows

- epi cells migrate over flap margins/border, contact tooth

Question 6

what happens in the first 3-7 days of wound healing?

Answer 6

• continued epi migration
• PMN replaced by macrophages (eliminate debris)
• blood clot replaced by granulation tissue
• revascularization begins

Question 7

what happens after 1 week of wound healing?

Answer 7

• epi attaches to the root (JE)

- blood clot replaced by granulation tissue derived from gingival CT, bone marrow, or PDL

Question 8

what happens after 2 weeks of wound healing?

Answer 8

• collagen fibers are oriented parallel to tooth (non-fxnl); they are immature
• weak union of flap to tooth

Question 9

what happens after 1 month of wound healing?

Answer 9

• inflammatory cells mostly gone
• fibroblasts proliferate, synthesize collagen
• revascularization regresses
• gingival crevice is fully epithelialized
• epi attachment well-defined
• supracrestal fibers now functionally arranged

Question 10

what happens after 2 months of wound healing?

Answer 10

• collagen has remodeled and cross-linked

- wound regains most of original tensile strength

Question 11

what happens to bone when it is exposed during flap surgery?

Answer 11

• superficial bone necrosis occurs after 1 - 3 days
• osteoclastic resorption follows, peaks at 4 - 6 days
• 1 mm of bone is lost when bone is exposed to oral environment

Question 12

what steps can be taken to ensure the best surgical outcome?

Answer 12

• minimize tissue trauma
• minimize dessication (irrigate w/ saline, go faster)
• suture carefully
• know systemic health concerns before surgery (ex: diabetes, bleeding disorders)
• preserve blood clot
• minimize bacterial colonization at site
• be aware that smoking impairs healing

Question 13

how does wound healing by secondary intention differ from primary intention?

Answer 13

• more vigorous inflammatory response
• larger volume of granulation tissue to fill defect
• more pronounced wound contraction during healing (more gingival shrinkage)

Question 14

what provides most of the signals for wound healing?

Answer 14

blood clot is the major source of growth factors and cytokines

Question 15

what growth factors are released from the clot?

Answer 15

• PDGF = fibroblast migration/proliferation, macrophage migration/activation
• EGF = epithelial proliferation
• TGF- β = migration of inflammatory cells, proliferation of fibroblasts

Question 16

what cytokines are released from fibroblasts and macrophages for wound healing?

Answer 16

• TNF = activates endothelium, induces PMN migration
• IL-1 β = activate endothelium, induce PMN migration
• Assuming notes are referring to cytokines released immediately after the wound occurs, in adjacent macrophages and fibroblasts, not those that come from chemotaxis relating to the clot that forms

Question 17

how does gingivectomy affect post-surgical size of the periodontium?

Answer 17

some bone resorption and AL will occur

Question 18

how does an apically-positioned flap differ from a modified Widman flap in terms of post-surgical outcomes?

Answer 18

• apical flap excises the tip of alveolar process
• modified Widman flap bevels the tip of alveolar process
• thus, modified Widman causes less resorption and AL than an apical flap

Question 19

how does repair differ from regeneration?

Answer 19

• repair = replacement tissues don’t duplicate architecture or function of original tissue
• regeneration = replacement tissues DO duplicate architecture and function of original tissue