Surface analysis of 2 orthodontic mini-implants after clinical use

•The morphology of mini-implants was analyzed before and after clinical use.•The 2 types of mini-implants had different shapes and morphology.•After use, the mini-implants showed plastic deformation and surface degradation.•The performance of orthodontic mini-implants can be affected by the manufacturing design.

IntroductionThe purpose of this study was to analyze the design and surface morphology of 2 brands of mini-implants before and after 12 to 18 months of clinical use.MethodsWe studied 22 mini-implants sold in the Brazilian market by 2 companies (Forestadent, Pforzheim, Germany; and Dental Morelli, Sorocaba, São Paulo, Brazil). The surface morphology of the mini-implants was analyzed by scanning electron microscopy before and after insertion in the oral environment to aid orthodontic movement.ResultsThe Forestadent and the Morelli mini-implants showed different shapes (size, screw thread design), and the surface morphology changed after clinical use. The most important surface morphology alterations after clinical use were strain in several parts and fracture of the active thread part of some mini-implants.ConclusionsThe results of the analyses showed that the screw threads of the mini-implants differ in pitch, angle, and length. The mini-implants also showed differences in body design, active tip, and taper. These differences affect the performance of the mini-implants. After clinical use, all mini-implants showed surface degradation, plastic deformation, and some fractures.