Implantology Flashcards
(36 cards)
Predictors for long term success of implants
- Sufficient volume of healthy bone
- Density of bone
Healthy bone to house adequate size and no. of implants
Failure of impants associated with bone with low mineral content
Main clinical manifestation of a successful implant
- Absence of mobility
Main determinants of implant stability
- Mechanical properties of the bone tissue at implant site
- Implant engagement with bone tissue
Mechanical properties of the bone tissue at implant site dettermined by
- Composition of bone at implant site
- Stage of healing
Trabecular bone transformed into dense cortical bone near implant surface
Transformed into dense cortical bone near implant surface
Trabecular bone
Implant engagement with bone tissue dettermined by
- Surgical technique
- Design of implant
- Osseointegration process
Successful healing of implant results in
- Bone formation reinforcing interface zone
- Forms bridges and direct contact between implant surface and surrounding bone
Unsuccessful healing of implant results in
- Interface fibrous scar tissue
- Caused by infection or mobility of implant after placement
A clinically stable implant shows a degree of mobility
True
This is on the microscale for example the application of a lateral load(bending)-implant is displaced and then returns to natural position
Types of load implants are subject to
- Axial
- Lateral
- Rotational
Axial loads direction
Push in /pull out direction
Lateral loads direction
Any direction 360 degrees around implant
Rotational loads direction
Clockwise or counter clockwise
Primary implant stability
Contact between implant surface and surrounding bone at placement
Primary implant stability depends on
- Bone
- Surgical technique
- Implant design
Implants
Biomechanical properties of bone dettermined by
- Ratio of cortical to trabecular bone at implant site
Cortical bone for implants
- Outer layer of bone beneath periosteum
- Densly packed mineralised lamallae
- 10-20 stiffer than trabecular bone->better support
Trabecular bone for implants
- Porous structure
- More soft tissue components than mineralised tissue
Surgical technique effect on implant stability
- Choice of drill diameters
- Depth of preparation
- Whether pretapering is used or not
- 1 degree implant taper
Using thinner drill diameters, omitting pretaperinf and use of a tapered implant results in higher primary stability
Secondary implant stability
- Delayed bone response after implant placement
- Change in cortical/trabecular bone ratio
- Increasing degree of bone implant contact
- 12-18 months
Other endogenous and exogenous factors that influence implant healing and bone remodelling capacity
- Patient general health
- Use of drugs
- Smoking
- Irradiation
Overload threshold is lower for
Implants with low stability than for one with high stability
Bone healing response after implant placement
- Blood clot formation
- Fibrin network provides scaffold
- Mesenchymal cells in granulation tissue differentiate to preosteoblasts then osteoblasts to form bone
- Erythrocytes, leukocytes, thrombocytes
- Aids migrating cells involved in formation of new vessels, extracellular matrix and bone
Stages of bone regeneration
- Immature woven bone replaced with mature lamellar bone
- Early bone formation after 3-4 months
- Remodelling process of repair-another 9-12 months
- Performed by bone metabolising units-osteoclasts and osteoblasts
