Resonance frequency analysis study with delayed and immediate ITI implants

Objectives: the objective of this study was to analyze by resonance frequency analysis (RFA) after 3 months of implant placement according to immediate and delayed loading protocols The objective was to compare implant stability changes of delayed loaded (DL) and immediate loaded (IL) ITI SLA implants. Methods: two groups' patients whose bone type was class II (the classification of Lekholm & Zarb) were enrolled, 12 patients received 15 IL implants and 47 patients received 79 DL implants. Apart from clinical and radiographic examinations, the implant stability quotient (ISQ) was recorded at implant placement, after 1-8, 10 and 12 weeks. Statistical analyses were carried out to study the possible differences between immediate loaded implants and delayed loaded implants. Results: one of the 15 implants in the IL group failed, and no implant was lost in the DL group. The cumulative survival rates after 3 months of loading were thus 93.3% and 100% for immediate and delayed loading protocols, respectively. RFA showed a distinct different pattern between IL group and DL group. The implants of IL during the course of the study showed a significantly lowed stability from ISQ 80.33 ±1.07 at placement to ISQ 71.33 ±2.31 after 2 weeks, and then increased slowly. But the implants of DL showed a lowed stability from ISQ 76.77±4.78 at placement to 74.52 ±4.79 after 4 weeks, and then increased slowly. Conclusion: the results suggested that implants of IL had their stability decrease significantly during the first 2 weeks before remaining stable. But implants of DL had the stability decrease mildly during the first 4 weeks. This information may be useful for avoiding implant failure by DL or IL implants with RFA. Furthermore the difference of implant stability change during healing phase may predict the different osseointegration between IL and DL implants.