## 1 Introduction  
First molars are the first permanent teeth to erupt and play a fundamental role in maintaining the shape of the dental arch and adequate occlusal schemes. The early loss of mandibular first molars is fairly common among adult patients, as these teeth are present in the oral cavity for longer and are thus more prone to caries, endodontic and periodontal problems, or vertical fracture [1], all due to poor oral hygiene maintenance [2, 3]. The premature loss of a permanent first molar must be dealt with immediately to avoid functional and anatomical disorders. As a result of first molar loss, mesial inclination and rotation of the adjacent teeth can occur, which causes a reduction in the prosthetic space available for rehabilitation [2, 3, 4]. If the inclination is not corrected, this aggravates periodontal problems in mesially impacted molars, causing inflammation, angular bone loss, a periodontal pocket on the mesial aspect of the second molar, and increased plaque retention leading to interproximal caries [5, 6, 7, 8]. Various treatment options are available for substituting single posterior teeth: a removable partial prosthesis, a tooth-supported fixed single or partial denture (FPD), or an implant-supported single or FPD. Lately, the latter option has become the treatment of choice for replacing single missing teeth, as it provides demonstrably good clinical outcomes [9] while preserving the teeth adjacent to the dementulous space, creating better conditions for oral hygiene maintenance, reducing the sensitivity of the adjacent teeth, improving esthetics, and preserving bone [10]. Inclined molars cause problems, especially when it comes to planning the replacement of missing teeth. Placing an implant in the dementulous space demands a series of conditions including adequate bone volume, healthy adjacent teeth, and sufficient mesiodistal space between the adjoining teeth. In cases in which the mesiodistal first molar space is reduced, various techniques can be used to straighten the inclined second molar, move it to its correct position, and obtain the prosthetic space needed. Recently, the use of miniscrews has been introduced for this purpose [1; 11; 12]. The minimum prosthetic space needed beside adjoining teeth to replace a lower first molar is 6.5 mm, as the mesiodistal width of the tooth usually ranges between 8 and 12 mm. Spaces of less than 6.5 mm do not permit prosthodonic rehabilitation of the missing molar, as it does not provide enough room for the implant supported prosthetic crown. At the same time, a space larger than 12 mm needs two adjoining implants to support a single restoration to reduce the forces exerted on the cantilever extending to mesial and distal and to reduce the risk of abutment screw loosening [13]. Miniscrews or micro-implants are small temporary fixtures inserted in bone to use as anchorage during orthodontic treatment [14]. They are made from pure titanium or a titanium alloy and have diameters of 1-2 mm and a variable length of between 6 and 20 mm. They remain stable throughout orthodontic treatment, only suffering a minimal loss of anchorage and thus are very effective. This relatively new concept of skeletal anchorage is simpler, smaller, less invasive, and more economical. Moreover, miniscrews do not require a long interval between placement and force application since loading can commence immediately after placement [15]. The use of miniscrews provides effective management of dental movements in both anteroposterior and vertical directions [16; 17; 18; 19]. Miniscrews can be used in ways that impact on either the whole or part of the dental arch. Straightening the second molar and bringing it to its correct position normalizes function and stabilizes periodontal conditions [20]. It makes it possible to position the root perpendicular to the occlusal plane so that it is able to withstand occlusal forces and place the prosthesis' insertion plane parallel to the tooth axis [21; 22]. It also generates sufficient space for replacing the missing tooth.