Dental implant in the aesthetic area can be tricky, and there are several factors, such as lack of surgical planning, surgical guide inaccuracies, inexperience, and wrong placement in the insertion of the implant, all of which can result in osseointegrated implants placed in non-optimal positions that lead to poor prosthetic restoration. These factors must be evaluated before treatment to aim for a successful result [25, 26]. This matter could also affect growing patients since the vertical growth of the maxilla continues up until 25 years [23, 24], because of that, clinicians ought not to put osteointegration implants before this age. One alternative to the growing patient to maintain bone level and allow the use of a temporary fixed crown is mini-screws [27].
When the malposition of a dental implant is considered mild, it can be corrected by prosthetic modifications, such as the use of custom-made abutments, angled implant abutments, and methods of cementation of the prosthetic device rather than screw systems; however, when malposition is severe, it is necessary to perform an intervention directly on the implant [12, 19]. Removal of an osseointegrated implant usually requires invasive surgery and damage to the surrounding bone; Roy et al. reported in 2020 [5], the principal reasons for implant removal are periimplantitis and crestal bone loss, mispositioning only accounts for a 8.4%; some commonly used approaches for implant removal are reverse torque and trephine drills, reverse torque being not only the principal but also the most conservative approach requiring removal of little to no bone, trephine drills were indicated when torque values exceeded 200 N/cm; however, some of the reverse torque techniques described the need to use a trephine drill in the coronal aspect of the implant to ease the explantation, in addition, the success rate for reverse torque was only of 87.7%; it is also important to address immediate implant placement, in the mentioned study it was only possible in 22.3% of the cases among all presented techniques [5]. Due to the unpredictability of these procedures on the amount of bone left after surgery, some patients must undergo several surgical procedures that may often be necessary to complete a satisfactory result, such as bone a soft tissue augmentation before considering a new implant placement; also, all these procedures can present high costs for the patient and lengthen in total treatment time [5]. Segmental osteotomy has been described in some case reports as an additional alternative to relocate a mispositioned implant without the need to remove the implant itself, aiming for preservation of already achieved osteointegration and bone architecture and to lower the risk to require additional procedures before new implant positioning can be done [3, 6, 7, 9,10,11,12,13,14, 16,17,18,19,20, 22]. Nowadays, technology is an ally, making possible to plan all types of osteotomies which minimize error during surgical procedure; besides, the new implant position can also be planned to achieve a proper restoration. Stacchi et al. reported a case back in 2012 [12] using CBCT for a segmental osteotomy planning, from which he obtained a stereolithographic model of the maxillary bone and was then replicated in a stone cast model were the surgery was manually planned to further design a titanium guide to reposition the bone block including the implant; nonetheless, the osteotomies were not virtually planned and this can still provide some level of error during surgical procedure that can cause failure of the repositioning, which is why, in this paper, a surgical guide for the osteotomies was designed using 3D virtual planning, in order to reduce human error [12].
There are similar principles in cases reported in the literature, such as the vestibular approach always be the election of incision, preservation of the palatal or lingual vascular supply, care to avoid damage to adjacent natural teeth, and rigid fixation of the bone block [7]. Stacchi et al. suggested three fundamental factors to alveolar osteotomy for implants, maximum preservation of blood supply during the early phases of healing, minimum gap between the mobilized block and adjacent bone, firm and stable bone block fixation [7]. On the other hand, the absence of micromovements is a fundamental element in promoting osseous repair, because the absence of stability of the osteotomized segment can result in non-union or malunion of the bone fragment [28, 29]. The issue is the grand amount of differences in described techniques, from the osteotomy planning to the relocation of the bone segment; some authors even consider the approach of a distraction osteogenesis driven by orthodontic treatment, thus making difficult to unify techniques and therefore to analyze success rate and best approach.