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'".
Outcomes of a fluoride modified implant one year after loading in the posterior-maxilla when placed with the osteotome surgical technique
Purpose: This study was established to evaluate the clinical outcome of a fluoride modified (OsseoSpeed"1) implant used for the restoration of the posterior maxilla, where bone density is known to be low, utilizing an osteotome technique for bone condensation and sinus floor tenting where appropriate.
Materials and Methods: This report presents outcome data from the first 20 consecutive patients recruited to a prospective study of 45 patients in total. Patients received 2 or 3 OsseoSpeed implants per quadrant placed at least 7 mm apart and with 1 mm of bone circumscribing the implants. One stage surgery was applied and no open sinus lifts were performed.
Initial osteotomy preparation was via graded drills at 1500 r.p.m. and an assessment was made of bone density. Final osteotomy preparation was via osteotomes whose dimensions were specific to implant geometry. At this time any sinus floor elevation was undertaken for elevation of the Schneiderian membrane and grafting was employed at the surgeon's discretion, but only with autogenous bone. Any dehiscence or fenestration type defects were also grafted with autogenous bone and covered with a collagen membrane.
Unloaded healing took place for 6 weeks at which time the implants were restored with a provisional restoration. An assessment of stability was made using resonance frequency analysis (RFA) at 2 weeks postoperatively. Subsequent to loading, RFA measurements were taken again along with clinical assessment of mobility, plaque, bleeding and probing depth. Standardized radiographs were also taken to assess mesial and distal marginal bone at 6 weeks post loading and then again at 3, 6 and 12 months to determine changes in the level with respect to a reference point at the top of the implant. Definitive restorations were placed one year after loading.
Results: Seven males and 13 females comprised the group, with a mean age of 59 years. A total of 59 implants were placed of which 56% were in low density type 4 bone and the remainder were in types 2 or 3 bone. 34 implants were associated with an indirect sinus lift procedure and grafting with autogenous bone. For these implants, the mean bone height to the sinus floor measured 6.5 mm. 51% of implants were 11 mm in length and 27% were shorter than 10 mm. The majority were of a tapered design being 4.5 mm diameter at the crest.
Six implants were mobile at the 6 week evaluation and were therefore not loaded at this time. Another 6 implants were noted to lack primary stability and benefited from a delayed loading protocol, i.e. mean of 13.8 weeks. An additional 10 implants also had delayed healing but this was a deviation from protocol rather than out of necessity. Of the 12 implants that had mobility one was removed due to pain at 6 weeks.
When considering changes in implant stability over time the RFA revealed little change over the first year of loading for the pooled implant data. However, when grouped by bone quality there was a highly significant difference between types 2 and 4, (p < 0.001), with a significant effect of time, (p = 0.02).
No significant difference in crestal bone loss were found for placement with different techniques.
Indeed implants in types 3 and 4 bone showed no bone loss in 80% and 85% of sites respectively.
Discussion and Conclusions: Stability values were seen to increase significantly over time when implants were judged to have been placed in types 3 and 4 bone. Such changes were not apparent for type 2 bone. Marginal bone changes were similar to those reported with studies in which only a drilling protocol was used, suggesting that a comparable outcome is possible when using osteotome compression technique.
When considering the unstable implants all but one appeared to attain stability with time, and these remained integrated up to the endof the one year follow-up.
It can be concluded that the use of fluoride modified implants placed in the posterior maxilla using an osteotome technique achieve an acceptable clinical outcome even when subject to an early (6 weeks) loading protocol.
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