Influence of inter-root septum width on mini-implant stability

Objective: The purpose of this study was to evaluate the influence of the inter-radicular septum width in the insertion site of self-drilling mini-implants on the stability degree of these anchorage devices. Methods: The sample consisted of 40 mini-implants inserted in the inter-radicular septum between maxillary second premolars and first molars in 21 patients to provide skeletal anchorage for anterior retraction. The post-surgical radiographs were used to measure the septum width in the insertion site (ISW). In this regard, the mini-implants were divided in two groups: group 1 (critical areas, ISW≤3 mm) and group 2 (non-critical areas, ISW>3 mm). The degree of mobility (DM) was monthly quantified to determine mini-implant stability, and the success rate of these devices was calculated. This study also evaluated the sensitivity degree during miniscrew load, amount of plaque around the miniscrew, insertion height, and total evaluation period. Results: The results showed no significant difference in mobility degree and success rate between groups 1 and 2. The total success rate found was 90% and no variable was associated with the miniscrew failure. Nevertheless, the results showed that greater patient sensitivity degree was associated to the mini-implant mobility and the failure of these anchorage devices happened in a short time after their insertion. Conclusion: Septum width in the insertion site did not influence the self-drilling miniimplant stability evaluated in this study. Abstract