RESULTS.
The graft material, Bioplant HTR (Bioplant Inc.), always produced an immediate additional stabilization of the implants and helped stop bleeding. Because of its naturally slight negative charge of 210 mV, the material sticks to the titanium and the host bone, stays where it is placed, and seems to discourage the colonization of microorganisms. During the healing period, no allergic reaction, inflammation, swelling, or pain was ever reported. Significantly, no soft tissue ingrowth was ever seen clinically or radiographically. Nineteen implants were lost during the osseointegration period in six patients. All those patients were diabetic and/or heavy smokers. Interesting, however, was the fact that not all of the implants placed in those patients were lost. At least one implant always integrated normally.
After removal of those failing implants and after a healing period of 12 weeks, implants were again placed. Those implants showed little if any problems afterward, but the cases were considered to be failures. During the follow-up period of at least seven years and a maximum now of 10 years, not a single implant loss of the remaining 537 ITI (Straumann) implants was reported. No measurable loss of bone height and width was seen clinically or radiographically.
Of those 19 lost implants, 15 (79%) were hollow screws, resulting in the later use of more solid screw implants. Four of the six patients were male, and two were female.

CONCLUSIONS.
The 7 to 10 year follow-up shows that ITI (Straumann) onestage screw implants are indeed as predictable and successful as conservative two-stage implants. More importantly, they can be placed in extraction sockets in combination with a graft material. The material used here, Bioplant HTR (Bioplant Inc.), proved to be an excellent graft material for this purpose; extremely easy to use and highly suitable to stick to the implants and not migrate (Fig. 16). This alloplast alone and not mixed with autogenous bone but wetted with sanguinous marrow seems to act as a barrier membrane. It forms initially dense or very dense fibrous tissue under the gum flap, preventing epithelial and connective tissue ingrowth around the implant(s) and providing excellent osseointegration.
The hollow screw ITI (Straumann) type showed a much higher failure rate when compared with the ITI solid screw implant, perhaps in dicating that the hollow space inside the implant is the reason for the problem. Another important finding is that two maxillary implants combined with a ball retained overdenture are indeed sufficient if the immediate implants are placed in the maxillary canine or premolar sockets and if the mandible is also edentulous.
Applying replacement therapy, using single stage (ITI-type) implants in combination with this microporous composite polymer, is predictable and successful. However, specially designed (ITI-type) implants for use in extraction sockets and/or wider implants would even improve simplicity and success. Adding the extraordinary properties of the growth factors and cytokines24 to stimulate bone more rapidly (and of tissues) to this bone substitute would without doubt enhance the rapidity of osseointegration. This would fulfill the goal of replacement therapy by providing every clinician and, thus, every patient with materials to replace hopeless teeth and prevent the socalled inevitable alveolar bone loss postextraction in the most efficient, simple, and secure manner.

Addendum.
The author wishes to state that since the start of this study 10 years ago the range of ITI implants (Straumann) has changed. The company now offers the choice between a TPS (Titanium Plasma Spray) implant surface and an SLA (Sand-blasted, Large grit, Acid-etched) implant surface. Wide solid screw implants (diameter, 4.8 mm) are offered with a neck of diameter, 4.8 mm or diameter, 6.5 mm as well as. An Esthetic Plus type is also available in which the height of the smooth neck is only 1.8 mm. Also, the hollow types are reduced to only a 3.5-mm diameter hollow cylinder (15-degree angled or not) in their Esthetic Line, showing that their findings correspond with the above conclusion.  

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