Deflection of mini implants from its intended path of placement on varying bone densities

Knowledge of bone density in maxilla and mandible will allow the clinician to plan the anchorage strategies and placement of implants with necessary precautions. The study aims to evaluate the deflection changes of titanium alloy self-drilling mini implants from the intended path that occurs during placement in varying bone densities.

63 titanium alloy self-drilling mini implants of the lengths 6mm, 8mm, and 10mm with diameter of 1.3mm were placed in three homogenous solid rigid polyurethane foam (saw bone) with bone densities of 20pcf, 30pcf, and 40pcf simulating anatomic sites in maxilla and mandible. 7mini implants of each length in all bone densities were tested for study. The implants were inserted perpendicularly into artificial bone block held in a custom made stand. The bone blocks were then radiographically exposed and the deviation of the long axis of the implantfrom a true vertical line was measured.

There was a decrease in deflection of the mini implant with increase in density. On the other hand, increase in length resulted in increase in the amount of deflection.

Longer mini implants can be used in less dense bone as in maxilla, whereas shorter mini implants can be used in high dense bone as in mandible to increase the stability and success rate of implants. Bone density and implant length play a role in deflection of mini implant from its intended path of insertion. Key words:Orthodontic Mini implants, deflection, bone density, anchorage.