Introduction: During implant placement and surgical practice, it is not uncommon the contact or the violation of the continuity of important nerve fibers from the region of the mouth, resulting in characteristic symptoms in patients. Such injuries can result in legal repercussions against the dental surgeon, who to avoid them shall establish specific actions in his proceeding. Purpose: The objectives of this study were to present a forensic case, emphasizing the legal care that the dentist must have in the course of treatment and to guide forensic dentistry experts during the expertise exam. Case description: In this case, the patient had complications after the autogenous bone graft surgery. The graft was resorbed, and the patient had hypoesthesia in the graft donor area. The dental surgeon had not informed her about the risks of surgery, and had not applied the Consent Form. With proof of damage, there was disruption of the doctor-patient relationship and patient sought rights in court. Conclusion: The correct diagnosis and planning, the prior written consent, including the risks of the procedure, and appropriate management of patients decrease the clinical and legal complications in cases of dental error. Similarly, the expert must have a competent clinical approach, performing the indicated and appropriated tests for the proper valuation of the damage generated.