The minimum distance of 2 mm between a dental implant and the superior aspect of the inferior alveolar canal is essential to prevent injury to the inferior alveolar nerve, which can cause sensory disturbances or permanent nerve damage. Maintaining this safety margin ensures sufficient bone thickness to support osseointegration while avoiding nerve compression or ischemia. This distance also allows for minor deviations during implant placement without compromising nerve integrity. Hence, 2 mm is widely accepted as the minimal safe clearance to balance implant stability and patient safety.

Reference: Oral Implantology, Carl E. Misch, 4th Edition.