Connective Contour" is the unique and scientifically documented contour that increases soft tissue contact zone and volume, created when the abutment is connected to the implant. Connective Contour is also an original key feature of the Astra Tech Implant System™.
The summaries in this section highlight the understanding of soft tissue healing around and esthetics maintained by the Astra Tech Implant System.
Peri-implant tissues at submerged and non-submerged titanium implants
Purpose: To study the hard and soft tissue integration around Astra Tech components when used in a
conventional one-stage and two-stage transmucosal
surgical technique.
Material and Methods: This animal study used
the partially edentulated mandibles of 6 beagle
dogs. Three months postextraction, 3 Astra Tech TiOblast'" implants 8 X 3.5 mm were inserted unilaterally, with the most coronal bevel of the implants at the crestal cortical margin. Cover screws were placed and implants submerged for 3 months prior to a second surgical procedure to expose and secure UniAbutments of 1.5 mm and 3.0 mm in length. At the same time a further 3 implants were surgically inserted in the contralateral side, with the coronal bevel of the implants once again level with the crestal cortical bone. However for these implants, abutments were placed immediately and soft tissues sutured around them for transmucosal healing. All dogs were routinely followed-up with daily hygiene.
Radiographs were taken using a modified Eggen technique to allow the accurate measurement of mesial and distal bone levels at time of fixture placement, 3 months post insertion and 6 months post insertion. Measurements were made mesially and distally using an imaging system under light microscope.
Clinical examinations were carried out to record plaque scores and a modified gingival index. Animals were sacrificed 9 months after the first implantation procedure and implants were harvested en bloc prepared and embedded for ground sections or for the fracture technique to allow histometric analysis of the dimensions and type of hard and soft peri-implant tissues, with particular attention to the zone of connective tissue integration. In addition a digital assessment of bone-to-implant contact in both the coronal unthreaded and threaded portions of the implant were undertaken. Results were subject to statistical analysis.
Results: Clinically all implants included in the analysis demonstrated successful osseointegration and very low levels of plaque and excellent soft tissue health. Radiographs revealed that over the 9 months follow-up marginal bone loss measured as a mean 0.42 mm for implants subjected to the two-stage technique and 0.3 mm for those treated transmucosally. Histology revealed identical tissue types to be found in relation to the various implant components.
Histometric measurements revealed a very close approximation for the two groups with the junctional epithelium measuring as a mean 1.9 mm, the comใective tissue compartment measuring 1.17 mm and the distance from the abutment/fixture junction to the marginal bone level measuring 0.8 mm as a mean. With regards the morphometric measurements for the connective tissue zone again there was a very close approximation for all fractions including collagen, vessels, fibroblasts and residual tissues. Bone-to-implant contact for the coronal unthreaded portion measured 75.0% for the one-stage implants and 72.6% for the two-stage implants and 61.4% and 66.7% respectively for the threaded portions.
There was no statistical difference for any parameters measured.
Discussion: The notion that an implant can be left exposed at the time of surgical insertion, without impacting on the tissue integration has been questioned and studied with various implants. This study compared the two surgical techniques for the Astra Tech TiOblast™ fixture and UniAbutment. Results clearly indicated that the tissue types, their dimensions and morphometry were identical regardless of procedure and that the percentage of bone-to-implant contact and marginal bone height is also unaffected.
In similar experimental set up differences in radiographic bone loss compared to this result have been reported, in favour for the Astra Tech implant system. Differences most likely explained by the different design characteristics of the implant systems evaluated (i.e. features related to the characteristics and design of the abutment connection).
Astra Tech
BioManagement Complex 
