Extraction of the permanent teeth for retraction of the protruded front teeth is a routine approach in orthodontics. Various techniques such as headgear, Nance button, and transpalatal arches (TPA) have been proposed to achieve sufficient anchorage [5, 8, 9, 12, 28, 31, 45]. Nevertheless, anchorage control turned out to be highly demanding as the conventional approaches were commonly associated with anchorage loss, i.e., mesial migration of the posterior dental anchorage units.

In order to improve anchorage control, differential moments have been described and monitored in clinical studies [25, 26]. The outcomes were promising, but nevertheless, anchorage loss and unexpected space opening most probably due to activation failures have also been reported. Some authors suggested that consecutive canine and front retraction may be more effective than en masse retraction of the front segment to preserve anchorage. Despite this, the effectiveness of this approach is still discussed, and controversial outcomes have been reported [18, 60].

In the past two decades, temporary orthodontic anchorage devices (TADs) including orthodontic mini implants and mini-plates have been introduced to improve anchorage control [39, 56, 57]. Orthodontic implants can be loaded directly after insertion and are usually removed after treatment completion [17, 36]. Therefore, orthodontic mini implants most often have a smooth surface to ease removal [32], whereas mini-plates are more invasive and require surgical intervention and flap preparation [6]. For this reason, orthodontic mini implants are frequently used, and two concepts are predominant: One is to stabilize a dental anchorage unit by connecting it to the implant (indirect anchorage), and the other is to directly load the orthodontic mini implant with the reactive forces (direct anchorage) [42].

Accordingly, there is a need to identify if orthodontic mini implants are more effective to control anchorage compared to conventional devices, and to assess if the direct or indirect anchorage concept is more beneficial. The aim of this systematic review was therefore to address the following question: “In patients with a need for en masse retraction of the upper front teeth, what is the efficacy of orthodontic mini implants for anchorage quality compared with conventional devices?”