Must be able to resist deformation and disperse loads
Fracture Toughness: high ductility and low modulus allowing for crack blunting. Ti-6Al-4V has a fracture toughness of roughly 50MPa m (11). This high fracture toughness is excellent for dental applications because of the cyclic loading in the mouth. Mean loading rate is 100 N/s for a mean masticatory frequency of 70 chews per minute (6). The elastic match at bone/implant interface is important for physiological stress transfer. Ti has an elastic modulus of roughly 27 GPa and bone has an elastic modulus of about 15.2 GPa Fatigue: high resistance to fatigue crack nucleation because of optimized manufacturing processes A high density of alpha grains resists crack nucleation, thus, the size of primary alpha can be decreased as far as possible, while also decreasing the beta grain size (BCC) (7). This high density of grains and small lamellae will prevent cracks from propagating easily through the material because of the obstacles of grain boundaries. It is important to lower Oxygen content to prevent the alpha case; stiff, brittle case which has high fatigue sensitivity. Cycles to failure: the loads are at maximum 900 N, which is much lower than the fatigue limit of 35280 N (assuming 400 mm 2 surface area) for 0.085% weight oxygen (Ti-6Al-4V has a max of 0.13% oxygen (7)). As seen from the figure, the Ti-6Al-4V lasts for 10 7 cycles at loads of about 2.5e5 N which is 278 times larger than the maximum load in the mouth
Corrosion: Not very susceptible to stress crack corrosion because the mouth is not a location for strong acids. Ionic strength data for K1scc in Ti was shown for harsh conditions such as ferric acid or 1M HCl which are usually not in the mouth. Very low ionic strength as in the mouth showed little effect on Ti. But susceptible to Fretting Corrosion which is mechanically assisted corrosion Ti is known to exhibit material transfer and adhesive wear from the asperities on the opposing contact surfaces, leading to a higher coefficient of friction. aggravated by the alpha cast which is susceptible to wear Mechanism by which cracks nucleate. The asperities make break off leading fretting debris, continued corrosion of the fresh surface, and accelerate the crack nucleation stage of fatigue. Wear: poor wear resistance because of the oxygen cast (lowered resistance to crack growth); fretting corrosion If the screw is poorly fitted and there is micromotion, causing rubbing against adjacent bone, much debris of vanadium and aluminum in surrounding tissues is present (11). Improvement to wear resistance has been attempted by surface treatments, through the introduction of nitrogen to surface layers or ion implantation.
The patient should have come in with a new extraction site where a reamer is used to drill a hole into the subgingival bone that will accommodate the implant.
The first thing that a dentist does is remove all the sterilization-maintaining containers and wrappings and pick out the temporary abutment and implant parts, and lock them together by simply tapping the abutment into the implant socket.
Next you insert the implant with the temporary abutment attached into the hole prepared by the reamer. The implant is made to stay in its place by sutures that close up the flaps of the gums around the temporary abutment. The patient is then sent home for the soft tissue and bone tissue to heal and integrate the implant system.
After about 10 weeks, the patient comes in for another appointment and this is what things looks like after the healing period where you see the temporary abutment protruding above the gumline.
You then remove the temporary abutment from the implant by applying a pulling force with a simultaneous torque.
You then clean out the well of the implant socket and this is what it looks like from below, and notice the round groove of the soft tissue shaped by the head of the temporary abutment.
In the meanwhile, an all-ceramic crown is cooked and shaped onto the permanent abutment and the final result looks like this.
Finally, you insert and tap the permanent implant stem into the well of the implant and…
Presto, this is the final product. You can compare the aesthetic advantage of our system with a nonsubmerged screw system next to our implant. You can see metal at the gumline, whereas you won’t with any of our implants because the crown margin is below the gumline.
And this is just a radiograph of our implant happily in vivo.