Mini-implants in contemporary orthodontics part 2: clinical applications and optimal biomechanics

When orthodontic mini-implants (OMIs) became readily available in the early years of the new millennium they were initially ‘competing’ with existing osseointegrated fixtures such as restorative (dental) and orthodontic palatal implants. Therefore, the initial body of research work and publications focused on the biological and clinical factors which appeared to affect OMI success (stability) rates and whether this compared favourably with these other bone fixtures. Subsequently, as both clinicians and researchers began to see clear evidence of OMI stability and low morbidity, these fixtures became more widely utilized for anchorage reinforcement. These aspects have been extensively detailed, using the most recent research evidence, in the first paper in this series.¹ However, in recent years the focus has broadened to include new clinical applications, ie how may we use mini-implant anchorage optimally.² A large number of case reports have been published, often documenting impressive results of different types of malocclusions being successfully treated with OMIs. However, as pointed out by the late Dr Vince Kokich,³ some of these reports have strayed into bone anchorage usage at the expense of other clinical options, and this has perhaps caused a distraction from the quality and innovation of the majority of publications. Fortunately, based on a combination of these case reports, and especially from recent systematic reports (in the form of case series and randomized controlled trials), we can see that OMIs provide reliable anchorage. However, anchorage is only one part of the clinical picture, and these studies did not necessarily analyse the nature and range of biomechanical effects on the dentition.