**6. Complications of inferior alveolar nerve repositioning**

Nerve mobilization procedures are precise methods that require clinical experience, knowl‐ edge of anatomy, and the ability to intervene in the event of potential accidents and/or complications. [1] In the last few years, IAN repositioning has been used widely as an alternative to short implants or bone grafts for osseointegrated implant placement in the posterior mandible of patients who do not have sufficient bone height for conventional treatment. Among the advantages of IAN repositioning is the option to use standard implants with bicortical anchorage, increasing primary stability, which is essential in the osseointegra‐ tion process. Osseointegrated implants placed in combination with IAN repositioning present a lower risk of bone loss than short implants when both are placed in similar circumstances. [2] For clinical situations with less than the minimum height for short implants (5 mm), IAN repositioning is the technique indicated. [3] This procedure also increases the resistance to occlusal forces and promotes a good proportion between implant and prosthesis. [4] Com‐ pared to the option of performing a graft to allow placement of standard implants, in addition to the lower cost, IAN repositioning can be performed under local anesthetic, does not require a donor site, and has a lower morbidity rate. [5, 6]

IAN repositioning also presents many disadvantages. The technique does not recover the alveolar ridge anatomy and temporarily weakens the mandible. Mandibular fractures associated with endosseous implants have been documented and are generally related to high levels of resorption in edentulous mandibles. Also, nerve mobilization leads to many factors that can increase the occurrence of fractures. [7, 9] A large portion of the buccal cortex is removed, reducing the structural integrity of a region that is under constant stress during chewing. [8] In addition to that, sites that have been prepared and subsequently abandoned due to bad angulation or insufficient initial stability are areas of bone fragility susceptible to fracture. [7] Poor nutrition as a consequence of blood perfusion changes associated with this nerve mobilization can also be a cause of fracture. [10] Another disadvantage of IAN reposi‐ tioning is the risk of nerve damage. The duration and degree of neurosensory disturbance has been related directly to the amount of compression and tension applied to the nerve during the procedure, [11] or to chronic distension/compression of the nerve after the surgery. [12] Hypoesthesia, paresthesia, and hyperesthesia are the most common complications. [13]

The success rate of the lateralization procedure, regarding the osseointegration process, varies from 93.8% to 100%, and thus both patients and surgeons believe this to be a safe procedure; however, a small percentage of patients will have nerve damage for the rest of their lives. [14] Concerning the use of materials as barriers between the implant and nerve, there is controversy in the literature, because while some authors consider the use of resorbable membranes to be helpful, [4] others have observed faster healing of the bone wound without barriers, followed by the restoration of the mandibular canal. [15] One advancement is the utilization of piezo‐ electric devices, which allow the surgeon to perform the osteotomy without damaging soft tissue, because piezoelectric devices only affect mineralized tissues. In vitro tests have shown a lower risk of injury when piezoelectric devices are used compared to conventional rotary devices. [16]
