Mucosal irritation caused by cusps of upper and lower teeth represents a source of persistent, low grade mechanical trauma. This type of trauma can initiate and/or perpetuate oral lichen planus in a few susceptible patients. Here, we report a rare case of bilateral white linear striations in the buccal mucosa of a young patient, associated with sharp cusps. Oral lesions demonstrated a unique cuspal signature highlighting the causal role of subtle mucosal trauma in the genesis of reticular-oral lichen planus. Lesions appeared to be exacerbated by significant psychological distress experienced by the patient. Although the Koebner phenomenon is well reported in the cutaneous lichen planus literature, such presentations are relatively rare in the oral cavity. This report emphasizes the potential role of low-grade cuspal trauma/irritation in conjunction with psychological distress in the genesis of oral lichen planus.