 Astra Tech
BioManagement Complex
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 Immediate/early loading protocol
When high primary stability is achieved, immediate and early loading protocols have been reported safe and successful in the scientific literature.
In this section, you will find summaries on documentation of immediate and early loading using the Astra Tech Implant System'".
 A retrospective analysis of early and delayed loading of full-arch mandibular prostheses using three different implant systems: clinical results with up to 5 years of loading
Purpose: The current study was established to identify any differences that might exist between delayed and early loading with respect to implant success, hard and soft tissue response as well as prosthodon-tic complications over a 5-year period. In addition the study was designed to reflect a cross-sectional representation of clinical circumstances where different clinicians with differing expertise were using different implant systems.
Materials and Methods: 109 patients treated by one of 10 teams, each comprising a different surgeon and restorative dentist received fixed screw-retained mandibular bridgework, 55 with early loading and 54 with delayed loading. Subjects were retrospectively included in the study and their assignment to either the delayed (DL) or early loading (EL) group was according to the presence or absence of medical history in particular irradiation, diabetes, heavy smoking (> 20/day) or bruxing habit. As such this assignment was non randomized. 47 patients wore a full upper denture.
All patients received 4 to 6 implants in the mandible with those in the DL group benefitting from submerged healing. In the DL group patients received Mk III Branemark implants with either a machined or TiUnite® surface (BM, BTU) or Astra Tech TiOblast" implants (AT). In addition in the one stage EL group some patients received Straumann*- SLA implants (SLA). In the EL group prostheses were delivered within 2 weeks of surgery, while in the DL group prostheses were delivered after 3 months and the framework were either milled titanium (Procera) or cast gold. The patients in the EL group were instructed to stick to a soft diet for the first month.
All implants were radiographed at 3 months post surgery (baseline) and at 1 and 5 years. Changes in marginal bone levels (AMBLC) were assessed at x7 magnification. All clinical parameters related to peri-implant health were assessed and a note recorded of any adverse events related to the prostheses or soft tissues. The space between the prosthesis and soft tissues was measured by evaluating the thickness of impression material placed into the gaps at the central incisor, canine and second premolar positions to the nearest 0.1 mm. If prostheses were removed for any reason individual implant mobility was assessed. All prostheses were assessed for passive fit. Results were subject to statistical analysis.
Results: 26 Patients were lost to follow up. A total of 378 implants in 83 patients were available for analysis. In the EL groupl2 implants failed (4.8%), 6 BTU, 5 BM failed within the first year and 1 AT failed after the 5 years. In the DL group 5 implants failed prior to loading (2.1%), 3 were BM and 2 were BTU. After 5 years follow-up mean AMBLC from baseline measured -0.93 mm in the EL group and -0.53 mm in the DL group. Throughout the study over 50% of implants lost no bone in either group, however Br&nemark implants with a conical collar lost significantly more bone in the EL group (-4.20 mm), p < 0.01, most of which was lost at baseline. AT implants lost the least amount of bone over 5 years with a mean AMBLC of +0.15 mm in the EL group and -0.10 mm in the DL group. AMBLC for specific implants did not vary statistically between loading protocols.
Few soft tissue complications were noted with only 3 patients being diagnosed with peri-implantitis. All were restored with Branemark implant of both surface types. Soft tissue shrinkage was more evident in the EL group but was not significant. In both groups more shrinkage was noted anteriorly, approximately 1.0 mm.
Prosthesis survival was 92.5% in the EL group and 98% in the DL group. A variety of adverse events were recorded from veneer fracture to framework fracture in one case. Problems were notably more frequent in the EL group and statistically more common in the maxilla, p < 0.05.
On questioning, significantly more patients were satisfied in the EL group compared to the DL group, (p < 0.05).
Discussion and Conclusion: In general it was clear that while some differences exist between the frequency of complications, and maintenance between EL and DL groups which was clinically significant (p < 0.05), clinical success could be achieved with early loading, with a 92.5% prosthetic survival rate and a 94.4% implant survival rate. Some system specific differences in tissue response, notably maintenance of marginal bone was evident especially for the conical BM implants which lost significantly meg bone than any of the others, while the AT implants consistently demonstrated the smallest mean marginal bone level change. Nonetheless all syster were seen to perform equally well with comparabli survival rates over 5 years in function.
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