## 3 Results
### Types of Treatment  
#### 3.3.1 Orthodontic Implant Site Development  
Regarding the orthodontic implant site development, the most used appliance to perform orthodontic extrusion was a multi-bracket system; in only one study [9], a removable appliance was used. The multi-bracket approach was full bimaxillary in three studies [14; 29; 30] and partial in seven studies [5; 7; 8; 10; 11; 12; 13].  
In one study [8], a lingual appliance was used; in another study [13], ceramic brackets were used (Table 2).  
Different ways were employed to apply the extrusive force: three studies [8; 13; 29] used NiTi archives and a more apical bonding of brackets on the teeth to be extruded; one study [9] used elastic bands from orthodontic hooks bonded to the cervical region of teeth to be extruded and a removable appliance; one study [14] first used NiTi archives and a more apical bonding of brackets, then an SS archive with extrusion steps and intermaximillary elastics; three studies [10; 11; 12] used SS archives and extrusion steps; one study [7] used a Co-Cr archive with extrusion steps, L-loops and inset component for palatal movement; and one study [30] used an SS archive with L-shape loops.  
A low extrusive force (<100 g) was applied in all studies, but five studies [5; 8; 12; 29; 30] did not report data about the intensity of the force used to perform the extrusion. Regarding the extrusion ratio, the extrusion was performed slowly (mean of 1 mm/month) in six studies [7; 8; 9; 10; 11; 30], whereas the other five studies did not report any data.  
Just two studies [7; 11] reported the amount of tooth extrusion performed.  
Most of the studies used an SS archive as an anchorage during the extrusion; one study [9] used a removable appliance and one study [8] used a composite resin veneer pontic, while three studies did not report information about the anchorage used.  
The frequency of follow-up varied from 2 to 4 weeks in all studies.  
In all studies but one [14], a stabilization period followed the orthodontic extrusion. The retention period lasted from 1.5 to 6 months, depending on each study.  
Tooth extraction was followed by immediate post-extractive implant placement in all studies, except two [9; 12], where a delayed implant placement was performed 4-6 weeks after extraction.  
All studies but one [5] gave details about the type of implants used.  
Eight studies performed a follow-up from a minimum of 6 months [10] to a maximum of 6 years [29]; three studies [5; 8; 12] did not report information about the duration of follow-up. No complications emerged in all studies except two: in one study [11], one implant failed and gingival recessions (0.1-0.2 mm) were observed, whereas in another study [9], external root resorption and an interdental papillae deficiency were observed.  
Two studies [7; 11] only reported the implant survival rate (100% and 96% respectively).  
All studies referred to good treatment outcomes, with satisfying esthetic and biological results and a successful implant osteointegration, but only a few [5; 7; 11; 12; 30] gave quantitative data about the amount of bone and/or soft tissue augmentation and only one study [11] indicated the percentage of efficacy of the technique in the regeneration of bone and soft tissue in the future implant site (70% and 65%, respectively).