Orthognathic surgery aims not only at aesthetic improvement but also at functional enhancement, requiring detailed planning that involves orthodontic diagnosis and advanced radiographic examinations. Regarding the principles that guide this surgery, analyze the following statements:

I.In patients with mandibular retrognathia, mandibular advancement performed during orthognathic surgery can improve not only occlusion but also the patency of the upper airways, helping in the treatment of obstructive sleep apnea.
II.The use of computed tomography and three-dimensional digital planning is crucial for the accuracy of bone cuts and for predicting final results in orthognathic surgery, being the preferred method for detailed predictions of postoperative occlusion and facial profile. 
III.After orthognathic surgery, the use of fixation devices such as plates and screws is always temporary, and they must be removed after complete bone healing to avoid complications.

Select the correct alternative: