Dental Implants Flashcards
implants are used for prosthetic, therapeutic, diagnostic, or experimental purpose
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what type of bone graft can you have?
- autogenous/autograft (from your own bone somewhere on your body)
- allogenic/allograft – from another human but not you (e.g. cadaver)
- xenogenic/xenograft – from another species
- alloplastic – not biologically derived (synthetic)
- isograft –> tissue transplanted from someone of the same species genetically related to the recipient
what aregrowth factors?
naturals proteins that stimulate growth of certain tissues; bone morphogenic proteins
describe the events of osseointegration
within the 1st week: -coagulum (an inflammatory filtrate) is formed that fills the tissue chamber–>first tisgns of woven bone
within the 2nd week: the woven the bone is the bridging the gap; it becomes strong and fills the tissue chamber
what are the types of dental implants?
- superiosteal – often forms the framework for CoCr dentures
- submucosal
- transosseous
- endosseous - screws, cylinders, blades in jawbone; mayhold one or several prosthetic teeth, as well as a support for fixed or removeable prostheses
describe the types of bones
type I - hard and dense with less blood supply; lots of cortical bones (good primary stability); mostly homogenous compact bone; takes approx 5 mos to integrate
type II– thick compact, dense trabecular core (good blood supply); ~4 mos to integrate; ideal bone for primary and secondary stability
type III– thin cortical, dense trabec. (lots of blood supply –> good primary stab); not as dense as type II; takes more time to integrate–> 6 mos; extended gradual loading of the implant can improve bone density
type IV– thin cortical with dense trabec;least dense of all; additional implants need to be placed to improve implant and bone loading distribution; icremental loading can improve bone density but often bone grafting/augmentation is required; consequently, it takes the longest time to integrate (8 mos)
what are the advantages of pure titanium and Ti-Tialloy ((tivanium?)
- excellent mechanical strength
- chemical stability
- low toxicity and biocompatibility
what are the desired mechanical proerpties that you want an implant to have?
- high yield strength
- modulus close to that of bone
describe surface tx
surface composition and tompography play a critical role in integration; the surface should be corrosion free and resistant to wear and shoukd evoke a favourable biological response; treating the surface can lead to improved metal performace, acceptance by teh body, and decreased healing time
materials use: oxidation of Ti to form a TiO2 layer on the surface (prevents corrosion);
can also incorporate Ca or P ions into the surface layer; increase surface area for osseointegration (plasma spray with Ti (sig. increases SA), acid etch, aluminum oxide blast –> hydroxyapatite and tricalciumphosphate)
can use “passivation” to form a thin oxide layer by acid tx–> e.g. use nitric acid to provide a controlled, and uniform stable oxide film on the surface which imporves corrosion resistance and eliminates metallic contaminants from the surface
can use anodization –> biocoat, which forms a thick oxide; the thickness of the film is dependent on the voltage used
can use biodize– similar to biocoat but allows formation of an even thicker TiO2 layer within the range of micrometers
What is anodizatio ?
Formation of a THICK oxide layer formed by electric current
Describe passivation
Formation of a THIN oxide layer from acid tx
Why do we coat implants?
Help with stability, good for type iv bone, in case bone height is yoo short, a. Freshly extracted site, and grafted bond
Early stagr failure due to early failure of osseointegration
Late sage is failure to maintain acheieved osseointegration after loading, either from mechanical issues or biological issues
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