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 5-year prospective study of Astra single tooth implants
Purpose : To evaluate the Astra Tech single tooth implant system over a 5-year follow-up.
Material and Methods: 15 patients each received one Astra Tech ST implant (0 4.5 mm). 11 implants were short, measuring 11 mm and four measured 15 mm in length. Implants were placed according to recommended surgical protocol with the head of the implant 2 to 3 mm apical to the cemento-enamel junctions of the adjacent teeth. In total 6 central incisors, 8 lateral incisors, and 1 bicuspid were replaced. No additional ridge expansion or grafting procedures were used for any implants.
All implants were left to osseointegrate for 6 months prior to connection of the 0.0 mm ST abutment in 12 cases and the 1.0 mm ST abutment in 3 cases. Implants were temporized either with the ST coping or a temporary crown. Ceramometal definitive crowns were placed as early as possible. Patients were followed-up every 6 months to determine clinical stability of the crown and tissue health.
Radiographs were taken using a long-cone technique at crown cementation and annually thereafter, and were assessed at x7 magnification. Marginal bone level was measured with reference to a defined point at the top of the implant. Results were subject to statistical analysis.
Results: One patient was lost to follow-up. For the remaining 14 patients all attended their review appointments.
No implants have been lost and there have been no soft tissue problems and minimal bleeding on probing. Prosthetically there have been no recorded cases of abutment screw loosening. One crown has dece-mented and required recementation after 18 months. One further crown suffered porcelain fracture and required replacement.
Mean distance for the marginal bone level measured from the reference point to the most coronal bone to implant contact point was at crown cementation (baseline) 0.46-0.48 mm. No statisticaly significant change occurred in bone levels to the 5-year follow-up (0.36-0.43 mm at 5 year). 33% of implants measured no bone loss and in some cases there was a clear bone gain.
Discussion and Conclusion: The Astra Tech single tooth implant system was most effective at replacing missing teeth.
The system was simple to use and there were very few complications. All implants remained in function and screw joints remained stable throughout the study. Excellent soft tissue health was maintained around all implants.
Marginal bone levels were extremely well maintained over the 5-year follow-up and may be attributable to tine TiOblast surface and MicroThread design of the coronal portion of the implant.
Astra Tech
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