Final: Alveolar Ridge Preservation Flashcards
What are the types of bone loss for Maxilla vs Mandible?
- Maxilla:
- Horizontal Resorption
- Mandible:
- Anterior=Horizontal
- Posterior=Vertical
Periodontium Anatomy
- Bundle Bone
- Cortical Bone
- Cancellous Bone
Bundle Bone
- Lines socket
- Directly connected to tooth structure
- Sharpeys fibers
- 1st to degrade after extraction
- Next to PDL of drifting teeth
- Alveolar Bone Proper
- Cribiform Plate
- Lamina Dura
Cortical Bone
- Aka: Compact Bone
- Outer wall of bone
- Continuous with bundle bone
- Dense & Strong
- Primarily Lamellar Bone
- Provides primary stability to implant
Cancellous Bone
- aka Spongy or Trabecular Bone
- Below Cortical Bone
- Radiographic appearance→Mesh work
- Trabeculae: Primarily lamellar bone
Alveolar Bone Loss
- Horizontal or Vertical defects
- occur due to
- tooth loss
- fractures
- pathology
- Compromise ideal implant placement→Unfavorable outcome
- occur due to
- Johnson:
- Fastet resorption: 1-6 months
- Carl & Perspm
- Most bone loss= 6-24 months
- Amler or Nevin
- Most tissue contour Loss: 1st month
- avg 3-5mm in width at 6 months
- Most tissue contour Loss: 1st month
- Ashman:
- Bone Shrinkage in 2-3 years:
- 40-60% of height and width
- Life Bone loss rate:
- 0.5-1.0%/year
- Bone Shrinkage in 2-3 years:
Alveolar Bone Loss Classification: Edentulous Jaw
A-E; A=normal
Socket Healing: Research Studies
- Araujo:
- Flap vs Flapless Ext=No Difference
- Scala
- Monkey Study
- Tan
- Systemic Review
- rapid reduction in first 3-6 months
- Chappus
- Facial Bone wall > 1mm (Bone Loss 1.1 mm)
- Facial Bone wall ≤ 1mm (Bone loss 7.5 mm)
- Schropp
- Ext Posterior Teeth
- Lose 50% of width in 12 months
- ⅔ in 3 months
- Farmer:
- Ext anterior teeth (Esthetic zone)
- Lose 15% width in 6-8 weeks
- Greatest bone loss= Coronal & Vertical
- Cardaropoli:
- Dog teeth
Ridge Preservation
- Aka:
- site preservation
- Socket preservation
- minimize vertical and horizontal ridge alterations in post-ext sites
- Decreases bone resorption
- DOES NOT PREVENT
- Decreases bone resorption
- No Superior Techniques
- No Flap ⇣ resorption rate
- No RP→ ⇡ orofacial dimension of bone
- Dimensional Changes within 6 months
- Mean horizontal reduction=3.8 mm
- Mean Vertical Reduction=1.24 mm
- Can Perform under a non-implant restoration to maintain tissue level
Ridge Preservation: Treatment Considerations
- Careful technique
- Minimal traumatic extraction
- careful elevation, lunation, and suturing (Criss-cross/Cruciate)
- Preserve Buccal Plate
- if damaged, repair during ext
- Section tooth if necessary
Why do we ant to preserve the ridge?
- Maintain:
- existing soft & hard tissue envelope
- stable ridge volume
- optimal fxn & esthetics
- Simplify subsequent tx
Ridge Preservation: Contraindications vs Indications
- Contraindications:
- Infection
- Radiation
- Bisphosphonates
- Indications:
- Implant placed at later time
- Contour ridge for conventional prosth tx
- Positive cost vs benefits
- Adolescents
Ridge Preservation: Clinical Recommendations
- Elevate Flap and Place:
- biomaterials
- ridge contour or barrier membrane
- Devices
- ridge contour
- biomaterials
- Primary Wound Closure
- no comparison studies
- soft tissue punch, CT graft, etc.
- no comparison studies
- Materials with low resorption and replacement rate
- No difference b/w materials (fillers, membranes)
- except collagen plug alone
- No difference b/w materials (fillers, membranes)
What are the different types of bone grafts?
- Autograft
- Allograft
- Xenograft
- Alloplast
Autograft
- Same person
- Intraoral or extraoral
- Tuberosity
- chin
- ramus
- calvarium
- tibia
- iliac crest
- Intraoral or extraoral
- osteogenesis
- osteoconduction
- osteoinduction
Allograft
- From Different person
- DFDBA, FDBA, Puros
- Osteoinductive
- Osteoconductive
Xenograft
- From different species
- Bovine (Bio-Oss), Horse (Equimatrix)
- Osteoconductive
Alloplast
- Synthetic
- GEM21
- Osteoinductive
- Osteoconductive
Post-extraction Site Classifications:
- Class I
- Intact Extraction Site
- favorable anatomical conditions
- Class 2
- Intact Extraction Site
- partially favorable anatomical conditions
- Class 3:
- Partially Compromised Extraction Site
- unfavorable anatomical conditions
- Class 4:
- Severely Compromised Extraction Site
- Unfavorable anatomical conditions
Class 1 Post-Extraction Site Classification
- Intact Extraction Site
- Favorable Anatomical Conditions
- Buccal cortical Plate
- Intact or ≤ 20% wall damage
- Soft Tissue Level
- Optimal
- Bone Anatomy
- Good for 3D implant position & Primary Stability
Class 2 Post-Extraction Site Classification
- Intact Extraction Site
- Partially Favorable Anatomical Conditions
- Buccal cortical Plate
- Intact or ≤ 20% wall damage
- Soft Tissue Level
- Optimal
- Bone Anatomy
- Difficult Implant Position & Primary Stability due to
- Perio defects and lesions
- Adjacent anatomical structures
- maxillary sinus floor
- IAN
- nasopalatine canal
- Difficult Implant Position & Primary Stability due to
Class 3 Post-Extraction Site Classification
- Partially compromised Extraction Site
- Unfavorable Anatomical Conditions
- Buccal cortical Plate
- 20-50% resorption
- Soft Tissue Level
- Suboptimal
- soft tissue inflammation
- thin and scalloped gingival phenotype
- Suboptimal
- Bone Anatomy
- Good for 3D implant position & Primary Stability
Class 4 Post-Extraction Site Classification
- Severely compromised Extraction Site
- Unfavorable Anatomical Conditions
- Buccal cortical Plate
- > 50% resorption
- Soft Tissue Level
- Suboptimal
- soft tissue inflammation
- thin and scalloped gingival phenotype
- Suboptimal
- Bone Anatomy
- Difficult implant position & Primary Stability due to:
- perio defects & lesions
- adjacent structures
- Maxillary sinus floor
- IAN
- Nasopalatine canal
- Difficult implant position & Primary Stability due to:
Socket Shield Technique
- Leave natural buccal root of tooth
- place implant in it
Dehiscence
- A Slice without coronal bone
Fenestration
- a window apical of coronal bone
- intact coronal bone
How does a socket extraction remodel over time?
- Contains clots then osteoblasts
- Day 14=Woven Bone
- Until bone is completely filled at Day 180
What is the rationale for alveolar ridge preservation?
- Place implants later
- Contour ridge for conventional prosthetic tx
- positive cost to benefits
- adolescents
Which materials are used for alveolar ridge preservation?
- Autografts
- Allografts
- Xenografts
- Alloplasts
Socket Healing After Extraction
- Day 7-14:
- Granulation Tissue w/bundle bone degradation
- Day 30:
- Lamellar bone starts to form
- Day 60
- More Fat Deposition
- Day 90:
- Good amount of bone
Ridge Augmentation Techniques
- Distraction Osteogenesis
- high risk of infection & failure
- Guided Bone Regeneration (GBR)
- Block Autograft
- Block Allograft
- Ridge Split Techniques
- Combination
Guided Bone Regeneration
- Use barrier membranes to direct growth of new bone & soft tissue
- sites w/insufficient volumes or dimensions
- used for fxn, esthetics, or restoration
- Based on Guided Tissue Regeneration (GTR) principles
- Introduced by Dahlin
- rats
- 1988
GBR Regeneration Process
- Blood Clot
- Angiogenesis
- develop new blood vessels
- Granulation Tissue
- Osteogenic cells migrate
- periphery→center
- Deposits woven bone
- Lamellar bone forms
- Remodeling
- resembles bone growth
GBR: PASS Principle
- Primary Closure
- periosteal releasing incision
- remove membranes after 4-6 mos
- Angiogenesis (Blood Flow)
- formation of new BVs
- Stability
- Suture and anchor membrane and flaps
- Space Maintenance
- membrane b/w bone graft and gingiva
What is the Principle of Combination Therapy
- Membrane
- provides barrier
- Graft
- scaffold
- space maintenance
Ideal Membrane Characteristics
- Biocompatible
- Cell Occlusiveness
- Tissue Integration
- protect blood clot
- wound stabilized
- Space making
- for progenitor cells
- Manage Clinical
- Facilitate migration and proliferation of progenitor cells
- Bacterial infection resistant
Types of Barrier Membranes
- Non-Resorbable
- ePTFE, dPTFE
- socket grafting)
- Millipore
- Cellulose acetate
- Titanium
- ePTFE, dPTFE
- Resorbable:
- Collagen
- Synthetic: PLA, PGA, PLGA
- ADM
New Membranes
- Alginate
- New degradable copolymers
- Hybrid or nanofibrous membranes
- Amniotic membranes
Porosity Principle
-
Porosity
- 50-100 um → Bone ingrowth
- > 100 um (101-150)→ High vascular tissue
- > 150 um→ Bone with osteons
GBR vs GTR
- GBR
- on edentulous ridges
- GTR
- around teeth
Osteogenesis
- cells in graft form new bone
Osteoinduction
- Chemical Process
- BMPs convert neighboring cells→ osteoblasts→form Bone
- BMPs=molecules in graft
Osteoconduction
- Physical Effect
- Graft Matrix forms scaffold
- outside cells penetrate the graft → form new bone
Osteopromotion
- Materials that support:
- wound healing
- tissue regeneration
- do not initiate de novo tissue formation
Autograft
- Same person
- intraoral or extraoral
- tuberosity, chin, ramus, calvarium, tibia, iliac crest
- osteogenesis
- osteoconduction
- osteoinduction
Allograft
- From a different person
- DFDBA, DFBA, Puros
- Osteoinductive
- Osteoconductive
Xenograft
- From a different species
- Bovine (Bio-Oss), Horse (Equimatrix)
- Osteoconductive
Alloplasts
- Synthetic
- GEM21
- osteoinductive
- osteoconductive
Growth Factors
- GFs
- rhBMP2
- PDGF-BB
- FGF2
- Controversial Evidence
- Rapid Clearance→ insufficient GF conc in bone defects
- Deliver w/supra-physiological non-standard doses → therapeutic efficacy