The Astra Tech Implant System™ is designed and proven clinically to maintain marginal bone. Outstanding long-term (i.e. > 5 years) clinical results on the maintenance and preservation of the marginal bone is summarized here. Some of the articles even report on marginal bone gain around Astra Tech implants in several patients.
A 10-year follow-up study of titanium dioxide-blasted implants
Purpose: This prospective study set out to evaluate the 10-year cumulative survival rate and marginal bone levels at 199 TiO2-blasted implants.
Materials and Methods: Patients with either edentulous maxillae or mandibles were enrolled in the study on a consecutive basis. Patients with uncontrolled diabetes, alcoholism, irradiation or mental illness were excluded. Smokers (n - 4) were included. Of the 36 patients enrolled, 28 were available for their 10-year follow-up, with a total of 155 implants.
Implants (TiOblast'" 3.5, 4.0) were inserted according to manufacturer's recommendations and benefited from a submerged healing protocol of 3 to 6 months, at which time they were exposed for the connection of 20° UniAbutments.
Intra-oral radiographs were taken using a paralleling technique both at baseline (insertion of prosthesis) and annually thereafter. Radiographs were analyzed using image capture software. All bone levels were measured with respect to the implant reference point at the base of the most coronal bevel. All bone levels above this reference point were recorded as zero.
A life table was constructed which would compensate for the lost data and give a better reflection of the likely 10-year outcome for these implants.
Results: During the study observation periodonly 6 implants were lost, 3 of which were mandibular and 3 maxillary. All failures were early losses identified at abutment connection. The cumulative survival rate for all implants was 96.9% and for maxillary implants alone this figure was 96.6%.
There were few prosthetic complications and bridge screw fracture only occurred in one patient, and this was attributed to an illfitting framework. After a complete remake no further screws broke in this or any other patient. Survival rate of the superstructures was 100% after 10 years.
Soft tissues were recorded as healthy with an absence of bleeding on probing in greater than 90% of all sites.
For the 100 first inserted implants, marginal bone loss data revealed a mean of 1.27 mm from the reference point at the 7-year follow-up.
Discussion and Conclusion: This study represents the first 10-year follow-up for implants with a micro-textured surface of the order of 1.10 pm.
The cumulative survival rate was impressive being 97.2% for mandibular implants and 96.6% for maxillary implants, which is better than rates recorded for machined implants. In addition it is noteworthy that all failures were early, and no late failures were recorded. It can be speculated that TiOblast implants therefore perform better in low-density bone. The annual bone loss rate equates to 0.15 mm/year suggesting marginal bone remains stable at these micro-roughened surfaces. Furthermore the incidence of soft tissue complications appears to remain very low, which is likely a function of the conical implant/ abutment joint design.
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