# A Brief Review on Micro-Implants and Their Use in Orthodontics and Dentofacial Orthopaedics
## 3 Results
### Use in Orthodontic Clinical Practice and Dento-Facial Orthopedics
In the maxilla, the posterior teeth were distalized with 1.4 to 2.0 mm, a media of 3.5\({}^{\circ}\) of distal tipping, and 1 mm intrusion; in the mandible, the posterior teeth were distalized with 1.6 to 2.5 mm and 6.6\({}^{\circ}\) to 8.3\({}^{\circ}\) of distal tipping. The maxillary posterior teeth showed intrusion by 1 mm. There were increases in arch widths at the premolars and molars. The micro-implants' success rate was 89.7% and the mean treatment time was 20 \(\pm\) 4.9 months. Inter-premolar and interpolar distances have increased. In the adult group, the Frankfort horizontal to mandibular plane angle has decreased. Profile changes were determined by distal repositioning of the upper and lower lips [57]. In cases with maxillary dentoalveolar protrusion, the anchorage on micro-implants was more efficient in retracting the anterior group than the traditional anchorage [57]. The use of micro-implants produced less anchorage loss, and had a better effect for the high-angle patients than had traditional anchorage. Both systems proved their efficiency in reducing dental and alveolar protrusion. In skeletal Class III, orthognathic surgery the maxillary intervention could be avoided by using OMIs placed in the palatal bone between the upper first and second molars to intrude the posterior teeth. The maxillary occlusal plane rotated clockwise and increased the surgical mandibular setback; the vertical dimension was reduced. The distal movement of the chin was greater than the alternative surgical prediction with no change in the occlusal plane. The intrusion of the maxillary posterior teeth with OMIs prevented the need for upper jaw surgery in adult skeletal Class III patients [58]. The micro-implants as anchorage can be successfully used for the treatment of Class II malocclusions [59]. OMIs were included in a novel en masse distalization concept used for patients with canine sagittal distalizations of half of a cusp or more. One palatal micro-implant on each maxillary side was introduced in the interradicular region. The objective of the study was to get a complete en-masse distalization of the whole upper arch in one step. By maxillary tooth movements and dentoalveolar compensations, the canine neutral relationship and the overjet correction were achieved [59]. OMIs can be used in lingual straight wire appliances for retraction of the frontal maxillary group [60]. The study used 3D finite element models and analysis software ANSYSnsys Workbench 15 (ANSYS, USA). The OMIs were positioned at 8 mm from the alveolar crest. On the OMIs positioned between the two central incisors was applied a vertical traction force for the simulation of the intrusion anterior from the bonded threads. The retraction hooks were positioned between the lateral incisor and the canine at a height of 6 mm. A retraction force of 1.5 N from the retraction hooks to OMIs was applied; the additional intrusive force of 50 g from the two incisors was combined to simulate the effect on labial crown torque. The double wire was more efficient in torque control compared with the single round or rectangular wire or in lingual orthodontics [60]. En-masse bodily movement of anterior teeth seemed to be difficult although the vertical intrusion force increases by using OMIs increased. En-masse distalization in the maxilla requires antibiotics or a placebo before the micro-implant's placement. However, a study on 38 participants [61] proved that antibiotics provided no benefit in terms of OMIs stability, inflammation of soft tissues, and postinterventional pain. Measurements of inflammatory markers in serum were inefficient in demonstrating soft tissue inflammations. Antibiotic prophylaxis slightly decreased the levels of the biomarkers. Regardless of the severity of obstructive sleep apnea (OSA), the use of oral appliances is preferred when nasal continuous positive airway pressure (CPAP) is not efficient [62]. Micro-implant assisted rapid maxillary expansion is effective in treating children with OSA and maxillary constriction.