Wound Healing And Anatomical Considerations For Implants Flashcards
Who discovered that when pure titanium comes into direct contact with the living bone tissues, the two form a permanent adhesion (osseointegration)
Professor Per-Ingvar Branemark - father of modern day implantology
Types of implant healing
Fiber integration
Fibo osseous integration
Osteo integration
Fibro osseous integration
-Tissue to implant contact with dense collagenous tissue between the implant and bone
-initially good successor ate but extremely poor long term success
-failure by todays standards
-soft tissue contact with implant
Osseointegration
Direct connection between living bone and load bearing endosseous implants at the light microscopic level
Repair
Results in tissues that are structurally and functionally different form their pre injury sites
Regeneration
Results in tissues that are structurally and functionally similar to their preinjured site
GTR
Guided tissue regeneration
In periodontal defects include furcation of new bone, cementum, and PDL (around tooth)
GBR
Guided bone generation
On bone
Stages of bone healing
Phase 1= inflammatory phase
Phase 2= proliferation phase
Phase 3= maturation phase
Phase 1- inflammatory phase Days
1-10
Things that happen in phase 1 (inflammatory phase)
Platelet aggregation and activation
Clotting cascade activation
Nonspecific cellular inflammatory response
Specific inflammatory response
Macrophages mediated inflammation
Phase II proliferative phase days
3-42
What happens during phase II (proliferative phase)
Neovascularization on the clot
Differentiation, proliferation and activation of cells (fibroblasts —> osteoblasts, osteoclasts)
Production of immature connective tissue matrix (Granulation tissue)
Phase III (maturation phase) days
After day 28
What happens during the phase III (maturation)?
Remodeling of the immature connective tissue matrix with coupled resorption/depostion of bone
Physiologic bone resorption
Bone modeling
When bone resorption and bone formation occur on separate surfaces
Formation and resorption are not coupled
Causes change in bone shape
Ex. Ortho forces
Bone remodeling
Replacement of old tissue by new bone tissue
Formation and resorption are coupled at same site
No changes in shape
Normally: implant site healing
Junctional epithelium
Attaches to implant surface by basal lamina and hemidesmosmes (same as teeth)
Connective tissue attachment
Fibers parallel to implant surface
No direct attachment to implant surface
20nm amorphous glycoproteins layer between CT and implant
Biological width
Peri implant biological width is similar to width around natural teeth and serves similar protective barrier functions
THE WIDTH IS LARGER THAN BIOLOGICAL WIDTH AROUND TEETH DUE TO LONGER JUNCTIONAL EPITHELIUM
Peri-implant CT fibers are generally parallel to the implant surface, tight adhesive attachment to the implant surface
Why is it important to have maintenance of the soft tissue seal (junctional epithelium, CT)?
Prevent peri implant mucus it is and peri implantitis
Bacterial can pass through easier on an implant surface than on a tooth surface
Marginal inflation —» ________ —-> per implant bone loss ——-> ________ —-> eventual implant loss
Apical spread ; peri implanttitis
How is the tissue interface around the implant similar/different to tooth?
Has junctional epithelium and CT but no PDL
Weak attachment
Does inflammation spread faster from soft tissue to implant or soft tissue or tooth?
SOFT TISSUE TO IMPLANT
Peri implant sulcus
Microbes more pathogenic
Factors that affect healing
Surgical technique
Pt selection
Oral hygiene
Bone density
Site selection
Surgical technique
Frictional heat= temp threshold is 47 degrees C
Greater = failure to achieve ossoeintegration = thermal injury
Necrosis of bone
How can you reduce heat
Gentle surgical technique, using sequential drills, use sharp drills, copious irrigation, use drills at recommended RPM
Drilling sequence for osteotomy
Small to large
Surgical technique two methods
Delicate soft tissue manipulation - maintain periosteal integrity and keratin end tissue and soft tissue biotype
Periosteum - has blood vessels and local osteoblasts, important for bone healing
Compression necrosis
Drilling into dense bone - compression of trabecular marrow space, lost blood supply, necrosis
Dependent on - high insertion torque and high bone density type
D1 bone density
Oak/maple wood
D2 bone density
White pine or spruce wood
D3 bone density
Balsa wood
D4 bone density
Styrofoam
Cortical bone density
Mandible > Maxilla
Most dense
Mandibular anterior - less blood supply
Least dense
Maxillary posterior
Poor quality
Soft bone but good blood supply
Anterior vs posterior cancellous
Anterior = more
Posterior= less
Rough surface implants
Majority of implants today
Increase roughness (surface treated, HA coats, plasma sprayed, sand blasted
Increase SA, cellular attachment, primary stability, bone implant contact, success rate
Machined surfaces
Smooth surface
More bone loss than rough
Decrease primary stability, less success, not used anymore
Primary stability
At time of implant
Decrease over time - 1st osteoclastic activity followed by osteoblastic response
Osseointegration and healing occurs —> secondary stability (1-2 weeks)
Most important during placement
Micro movement of implant is the most common cause of implant failure (fibrous encapsulation)
Mylohyoid ridge
Careful palpation —> concavity below the ridge anteriorly (sublingual fossa), posteriorly (submandibular fossa)
Implants in post mandible high risk entering submandibular fossa ( highly vasuclarized) —> hemorrhage
Can be life threatening
Inferior alveolar nerve and mental foramen
Minimum 2 mm safe distance between implant and nerve
Canal is surrounded by cortical bone —> however, tactile feedback cannot be relied on
No substitutes for radiometrics, pre, intra, post operative PAs super important
When in doubt CBCT
Anterior loop of Ian
Majority of cases —> anterior loop is present
Average loop dimensions: 3 mm
PLACE IMPLANT AT LEAST 5 MM ANTERIOR TO THE LOOP - distance from implant surface to foramen not the osteotomy
Mental foramen
Differs in horizontal and vertical plane
2mm distance between implant apex and foramen
When in doubt, can surgically locate the foramen
Lingual nerve
75% times
3 mm apical to the crest of the 3rd molar and 2mm from the lingual cortical plate in the flap
Avoid lingual vertical incisions
Nasopalatine foramen and canal
Contains nasopalatine nerve and sphenopalatine artery
Could be at site of implant placement
Complete degranulation of canal —> place implant —> graft the canal
Greater palatine foramen and artery
Greater palatine artery foramen - near 3rd molar
When harvesting tissue graft- careful reflection to prevent hemorrhage
Maxillary sinus pneumatization
Need sinus lift either lateral wall or osteotomy mediated
