SCREW LOOSENING AND SCREW FRACTURE:
One of the important complication in 2 piece or 3 piece Implants.
Adverse occlusal forces can result in mechanical complications of implants.
While unacceptably high incidences of mechanical failures have been reported for the 2-stage external hex screw type Implant systems.
what is Screw Loosening:
Due to improper occlusal forces, the screw connecting the Implant and Abutment get loosen. This is screw loosening.
What is Screw Fracture:
After screw loosening, metal fatigue may result in screw facture or fixture fracture and causes loss of Implant.
Causes of Screw Loosening and Screw Fracture:
screw-joint stability involves 3 most important factors:
1.Adequate pre-load:
Application of correct torque to an Implant screwis translated into a pre-load that holds the components together.
Pre-load is the only force that will resist the patients functional occlusal forces inorder to keep the abutment from separating from the implant.
If the pre-load exceeded by occlusal force, the screw will loosen.
2. Fit of the Mating Implant components:
Improper positioning or fixation of the abutment with the Implant.
3.Screw Design:
There is an Anti rotational feature of Implant abutment interface. If there is no precise anti-rotational feature, screw will loosen.
Management of screw loosening:
For a 2 piece or a 3 piece Implant :
8 degree Morse taper, 45 degree bevel on the implant shoulder has minimized the risk of screw loosening.
Design of standard diameter solid screw ITI implant and material used in its fabrication has minimized fixture fracture.
Use of Single Piece Implant System:
One of the important complication in 2 piece or 3 piece Implants.
Adverse occlusal forces can result in mechanical complications of implants.
While unacceptably high incidences of mechanical failures have been reported for the 2-stage external hex screw type Implant systems.
what is Screw Loosening:
Due to improper occlusal forces, the screw connecting the Implant and Abutment get loosen. This is screw loosening.
What is Screw Fracture:
After screw loosening, metal fatigue may result in screw facture or fixture fracture and causes loss of Implant.
Causes of Screw Loosening and Screw Fracture:
screw-joint stability involves 3 most important factors:
1.Adequate pre-load:
Application of correct torque to an Implant screwis translated into a pre-load that holds the components together.
Pre-load is the only force that will resist the patients functional occlusal forces inorder to keep the abutment from separating from the implant.
If the pre-load exceeded by occlusal force, the screw will loosen.
2. Fit of the Mating Implant components:
Improper positioning or fixation of the abutment with the Implant.
3.Screw Design:
There is an Anti rotational feature of Implant abutment interface. If there is no precise anti-rotational feature, screw will loosen.
Management of screw loosening:
For a 2 piece or a 3 piece Implant :
8 degree Morse taper, 45 degree bevel on the implant shoulder has minimized the risk of screw loosening.
Design of standard diameter solid screw ITI implant and material used in its fabrication has minimized fixture fracture.
Use of Single Piece Implant System:
- Single piece implant being a single component structure has no joints or a connecting screw.
- There is no screw and hence no screw loosening or fracture.
- No crestal bone loss.
- No marginal leakage between the implant components.
- Procedure can be done flapless and can be immediately loaded.
- patient comfort.
- Mimics the natural teeth in its construction.
visit us at:
thanks for this usefull article, waiting for this article like this again. Dental implants Northampton
ReplyDelete