A wide range of different surgical techniques are applied when placing implants under different preconditions. The summaries below show that one- and two-stage surgery, immediate placement in extraction sockets, bone augmentation and sinus lift can be successfully and predictably performed using the Astra Tech Implant System'".
Immediate provisionalization of single extraction-site implants in the esthetic zone: A clinical evaluation
Purpose: Demands continue to increase for a reduction in healing times and improvements in esthetic outcome for implant supported restorations. To this end much has been reported on the use of immediate loading protocols as well as the placement of implants directly into fresh extraction sockets, with or without the use of regenerative materials depending on the size of the residual socket defect and/or the presence of a dehiscencetype defect. This study was established to monitor success of immediate implants with immediate temporization by virtue of implant survival, maintenance of marginal bone levels and the maintenance of the interdental papilla.
Materials and Methods: Data on implants placed in 90 patients were evaluated. Implants were required to be non-adjacent, placed into fresh extraction sockets and had to achieve a minimum insertion torque of > 40 Ncm to qualify for immediate temporization in order to guarantee adequate primary stability. Presence of local infection was an exclusion criterion although if the infection remitted within one week of extraction under antibiotic therapy implants were then inserted into the still fresh socket. Molar sites were excluded from the study. According to the need for grafting, the time of implant placement (day of extraction or one week later) and the time of provisional prosthesis delivery (which varied from the day of surgery up to 14 days post-op) four groups were established.
Surgical approach varied according to the defect type and the need for augmentation. But in general all teeth were extracted atraumatically and buccal flaps were raised, including adjacent papillae to gain direct access to sockets and associated defects. Osteotomies were located towards the palatal and implants (Astra Tech, TiOblast"") were typically located with their shoulder 3 mm below the free gingival margin or 2 mm below the adjacent cemento-enamel junction. When implants were due to be immediately temporized, abutment connection was facilitated and these abutments were definitive and not removed again. Grafting was achieved using bovine bone mineral (BioOss) and when indicated covered with a collagen membrane (BioGide). Temporary crowns were fabricated from shells relined over white plastic prefab-ricated copings. When temporization was delayed a fixture pick-up was used to register the implant position for location in a study cast and laboratory made temporary crowns were then available for insertion 1 to 2 weeks post-op. Healing abutments were located, flaps repositioned and wounds sutured.
All temporary crowns were kept clear of contacts in centric and lateral/protrusive excursions. Intra-oral radiographs were taken at baseline (day of temporization), and one year after delivery of the definitive crown which was delivered typically 3 months post-op. Cumulative Implant survival (CIS), and changes in marginal bone level (MBL) were recorded.
Results: A total of 36 implants were included in the analysis and ranged from 9 to 13 mm in length and 4.0 to 5.0 mm in diameter. Implants were in full function for an average of 2.8 years (range 1-4.1 years). Two implants were removed within 2 weeks post-op. Both these implants were associated with a dehiscence-type defect. The CIS after one year was 95.3%. There were no late failures. MBL measured 0.18 mm mesially and 0.43 mm distally. There were no signifi-cant differences between the groups. Visually 78% of implants were associated with complete papilla pres-ervation.
Discussion and Conclusion: This study supports other previous studies in that it corroborates the efficacy and success of this technique. However this study is the first to report on combining the immediate placement with local grafting of dehiscence-type defects. It is worthy of note that the two early failures were both associated with such defects and a history of infection. Nonetheless the study suggests that such cases can in general also be associated with a successful outcome, with excellent maintenance of MBLs, which are typically known to exist with this brand of implant. This in turn was seen to help support a full interproximal papilla in 78% of cases and even some hyperplasia in a further 6% of cases. It can be concluded that while the presence of local infection might jeopardize success, the need for local grafting does not appear to inhibit outcome for immediately placed implants.
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