1. Platform switch – to be or not to be?
Andrija Petar Bošnjak
School of Dental Medicine, Zagreb, Croatia
Andrej Meniga
Private practice, Zagreb, Croatia
Ann Wennerberg, Victoria Fröjd
School of Dentistry, Göteborg, Sweden

2. Background Bone resorption to the first thread during initial loading
Biologic width around implants (Berglundh & Lindhe 1996)
No resorption when an abutment with a narrower diamater is connected to the implant (Gardner 2005) – so called platform-switching

4. Objective
Evaluation of the difference in histological findings between a platform-switching implant-to-abutment interface using a tight seal and a flat-to-flat interface
Differences in ISQ values during 3 months for implants with transmucosal healing (one-stage procedure)

6. Material and methods
26 consecutive patients treated with 43 Ospol study implants
4.0 diameter, implant length of 10, 12 and 15 mm supporting single crowns or fixed partial dentures
36 implants (83.7%) – single tooth replacements in lateral parts of mandible (58.8%) and maxilla (41.2%)

7. Material and methods Paired implants
One with a healing abutment – creating flat-to-flat interface
One with a standard abutment – creating platform switch interface

8. Material and methods
2×2 mm biopsy of soft tissue was acquired 3 months after implant placement for histological evaluation (at the time of crown/fixed partial denture fixation)
Immersed in sodium-cacodylate solution and subsequently analyzed

10. Material and methods Radiographic assessment of marginal bone level
At the time of implant placement
At 3 months recall (time of crown fixation)
All patients were recalled monthly during osseointegration process
ISQ measurements at the time of surgery and 3 months postoperatively

12. Results Inflammatory cell inflitrate Thickness of the epithelium
Cross-sections of fixated samples
Inflammatory cell inflitrate
Thickness of the epithelium
Thickness of the connective tissue

13. Platform switch No substantial number of inflammatory cells
Epithelial thickness
Well-defined “rete pegs”
Connective tissue layer

14. Flat-to-flat No substantial inflammatory cell infiltrate
Epithelial thickness
Connective tissue layer

16. ISQ measurements Platform-switch (± SD) Flat-to-flat p
At implant placement
72.5 ± 6.3
71.8 ± 5.9 NS
At 1 month
77.3 ± 4.2
77.1 ± 3.8
At 3 months
81.8 ± 5.5
80 ± 4.7

17. Conclusion
Histologic analysis is in the early stage, but there is no significant inflammatory cell infiltrate
Platform-switch seems to be as reliable for one-stage procedures as flat-to-flat interface
ISQ measurements confirm that the stability was maintained during initial three months of healing

19. Further developments

20. Further developments

21. Further developments

22. Acknowledgments Ospol, Malmö, Sweden
Göran Urde & Hans Ospol, Malmö, Sweden
Petra Hammarström Dept Biomaterials/Handicap Research, Göteborg, Sweden
Martina Vlah, Gordana Sporis & Lana Meniga & Bosnjak LLC, Zagreb, Croatia
Kresimir Sankovic, School of Pharmacy, Zagreb, Croatia
Drazen Jovicevic, Dental Laboratory, Zagreb, Croatia