CHAP 5- Bone regeneration Flashcards
1rt years exodontia
Mandible 4-6 mm
Maxilla 2-4 mm
After first years reabsorption
slow and progressive
more intense in the mandible tan in the maxillary bone
3/1 o 4/1
Manible : Arc widening
Maxilla : arc narrowing
Important Factors in Bone Regeneration
❖ Aesthetic and functional requirements of the patient
❖ Budget
❖ Tobacco
❖ Patient’s oral hygiene habits
❖ Availability of suitable donor sites ( in case of autologous grafting)
❖ Intraoral soft tissue status
Autologous graft
- Graft from the recipient’s own
- Body Extraoral and intraoral donor
sites
Homologous graft
allograft
allogenic graft
- Grafts from the same species
- Mineralised freeze-dried bone/des
(FDBA,DFDBA), fresh frozen
Heterologous graft or Xenografts
- Grafts from different species
- Bovine bone
Alloplastic or synthetic graft
- Laboratory synthesized inert material
- Bioceramics (HA, B-TCP), Polymers, Bioactive Glasses
Classification of Bone Grafts
BY ITS STRUCTURE
SPONGIOUS
+ o s t e o g e n i c c e l l s
- s t r u c t u r a l
s t i f f n e s s
+ r e s o r p t i o n
+ v a s c u l a r i z a t i o n
CORTICAL
- o s t e o g e n i c c e l l s
+ s t r u c t u r a l s t i f f n e s s - r e s o r p t i o n
+ o s t e o c o n d u c t i v e c a p a c i t y
Particulated bone
- Auto, Alo, Xeno,
- Alloplastic
- By itself, with plasma, with blood
Composite
Mixed with each other
Classification of Bone Grafts
BY Regeneration Mechanism
OSTEOGENESIS
- It is the formation of bone tissue starting from living
cells coming from the graft. ==> Autologous
OSTEOINDUCTION
- It is a process by which mesenchymal cells in the
recipient site a re-transformed into osteoforming cells . - This stimulus is provided by growth factors.
==>Autologous bone and Autograft
OSTEOCONDUCTION
- It is a phenomenon in which the graft serves as a guide for bone neoformation .
- It is colonized by blood vessels and osteoprogenitor cells of the recipient site .
- As it is resorbed, it is replaced by neoformed bone tissue .
==>All of grafts
Autologous dentin
❖ Studies with a larger sample size, and especially with a longer follow-up time, are needed to confirm the long-term stability of this material.
❖ Human dentin and bone tissue have a similar chemical composition.
❖ Autogenous dentin possesses osteoconduction and osteoinduction properties.
❖ Good results in terms of bone gain and consistency, and even better results compared to other materials
Gold standard
Autologous bone
Autologous bone = PROS
❖ No additional biomaterial cost
❖ No immunological reaction
❖ Osteo-gene/inducer/conducer
Autologous bone = CONS
❖ Donor area (additional surgery)
❖ Increased morbidity (2 fields)
❖ Limited availability of intraoral grafts
❖ Extraoral grafts: AG, QX…
❖ High resorption rate
❖ Not storable
DONOR SITES FOR AUTOGRAFTS
- Cortical/spongious
- Block/Particulated
Intraoral regions
Intramembranous: less reabsorption
Mandibular ramus
Mandibular body
Mandibular symphysis
Tuberosity
Extraoral regions
Endocondral: more reabsorption
Iliac crest
Tibia
Fibula
Calotte
objet for get bone
BONE SCRAPERS
rotatory instrument
Harvesting burs
Biological harvesting slow velocity
BONE SCRAPERS
P A R T I C U L A T E G R A F T S
ABSENCE OF STIFFNESS/MECHANICAL STRENGTH
===>
SOFT TISSUE COLLAPSE OVER THE GRAFT
+
PARTICLE COMPRESSION
==>
LOSS OF STABILITY
+
ACCELERATED RESORPTION
PA RT I C U L AT E G R A F T S
IN CASES OF DEFECTS OF MORE THAN ONE WALL, IT IS NECESSARY TO USE
TITANIUM MEMBRANES OR
MESHES THAT WILL KEEP THE GRAFT FREE OF TENSIONS.
GUIDED BONE REGENERATION
BIOLOGICAL PRINCIPLE THAT CONSISTS OF PREVENTING ACCESS TO THE AREA TO BE REGENERATED BY
CELLS FROM THE CONNECTIVE TISSUE AND EPITHELIUM, ALLOWING COLONIZATION OF THE SPACE BY
CELL LINES FROM THE BONE
WHAT IS MEMBRANE
ISOLATION BARRIER BETWEEN CONNECTIVE TISSUE AND THE BONE BED
==>
TARGETED DIFFERENTIATION OF BONE TISSUE TO PROMOTE BONE REGENERATION
M E M B R A N A E S
==>
P R O P E R T I E
Exclude gingival fibroblasts and epithelial cells from the regeneration zone
Mechanical stability : provide a stable space and protect clot and graft
biocompatible
integrate with surrounding tissues
Manageable
Low cost
M E M B R A N A E S
==>
USE
Extend 2 to 3 mm beyond the margins of the defect
good adaptation
Resorbable: hydrate before
Correct stabilization
RESORBABLE MEMBRANES
==>
NATURAL OR SYNTHETIC
Most used: Collagen tendons, , skin or pericardium / bovine or porcine
They vary according to: type, structure, degree of cross-linking (cross-linked) and collagen treatment.
Resorb/Resorption
FAST : 2-4 mouths
Medium : 4-mouths
Slow: more than 6 mouths
resorb/Membranes
Advantages
No 2nd surgery removed
Easy adaptation and handling
Good biocompatibility
resor/Membranes
Iconvenient
Lack of stiffness
Unpredictable degree of resorption
If exposed rapid resorption
Non Resorbable membranes/Mesh
ADVANTAGES
Dense surface to soft tissue.
Avoids fibrous tissue in the bone defect
Non Resorbable membranes/Mesh
Inconvenient
2nd surgery for removal
More complicated management
Higer rate of exposure (infection)
Resorbable membranes
Indications
- L O C A L A L V E O L A R R I D G E D E F E C T S ( L I M I T E D H O R I Z O N T A L O R V E R T I C A L )
- P E R I - I M P L A N T B O N E R E G E N E R A T I O N
- D E H I S C E N C E S A N D F E N E S T R A T I O N S A S S O C I A T E D W I T H I M P L A N T P L A C E M E N T
- B O N E D E F E C T S A S S O C I A T E D W I T H O S S E O I N T E G R A T I O N F A I L U R E S
- B O N E L E S I O N S
- C O V E R A G E O F S I N U S M E M B R A N E
P E R F O R A T I O N S I N S I N U S L I F T S
Non resorbable membranes / Mesh
INDICATIONS
ALL (same as resorbable)
More advantages but more difficult to work with and higher rate of complication incidence
Large defects (longer time and bone maturation): Vertical and some horizontal regenerations
PARTICULATE GRAFTS
OPTIMAL PARTICLE SIZE
0,25MM- 2 MM
CLINICAL USES OF PARTICULATE GRAFTS
(SOCKET PRESERVATION)
FENESTRATIONS AND DEHISCENCES (GUIDED BONE REGENERATION)
MAXILLARY SINUS ELEVATION
PERI-IMPLANT DEFECTS
FENESTRATIONS AND DEHISCENCES
NARROW ALVEOLAR RIDGES OR BUCCAL CONCAVITIES
DEHISCENCE(couvre pas jusqu’a l’apex): THE MOST CORONAL SPIRES ARE EXPOSED WITHOUT BONE COVERING.
FENESTRATION(fenetre): LACK OF BONE COVERING OF THE IMPLANT IN ITS APICAL PORTION.
GUIDED BONE REGENERATION
Tinti’s Technique
Vertical augmentation with immediate IOI
placement
GUIDED BONE REGENERATION
URBAN TECHNIQUE
SAUSAGE TECHNIQUE
(VERTICAL/HORIZONTAL AUGMENTATION)
- MIXTURE 1:1 : AUTOLOGOUS H. AND XENOGRAFT
- SLOWLY RESORBABLE MEMBRANE OF COLLAGEN FIXED WITH PINS.
- WAIT 8-9 MONTHS FOR IOI
PASS
Principe for predictable bone regeneration
Primary wound closure
Angiogenesis
Space creation/maintenance
Stability of initial blood clot and implant fixture
BLOCK GRAFTS
Sequence of block grafts
- Preparation of the recipient area
- Graft harvesting (in case of intraoral: chin, branch, tuberosity)
- Adaptation + fixation of the block
- Soft tissue coverage of the recipient site
- Closing of donor area
- Re-entry
Instruments for graft harvesting
- Crack milling cutter
- Oscillating saw
- Discs
- Trephines
- Piezoelectric
CLINICAL USES OF BLOCK GRAFTS
Khoury’s technique
Vertical and horizontal regeneration
- Procurement of autogenous block graft from retromolar area and split into two thin cortical
lamellae. - In the recipient area, the sheets are arranged in a box shape with micro-screws.
- Subsequently, the space is filled with autologous particulate bone.
- Waiting 4 months and placement of IOI
- In 2nd phase soft tissue augmentation
Complications
Intraoperative
- Hemorrhage
- Injury to vascular-nerve structures
- Bone fractures
Post-operative
Suture dehiscence and wound opening
Membrane and graft exposure
Infection
Complications
Resorption
❖ Bone grafts in apposition: high rate of resorption in the short and medium term
❖ Resorption rates during the first 6 months of 11-41.5%.
❖ If the graft is not subjected to mechanical stimulation: 92% resorption rate.
❖ Intramembranous bone resorbs less and revascularizes faster than grafts of endochondral origin
