The aim of this article is to review a group of lesions associated with periodontal ligament (PDL) widening.

An electronic search was performed using specialized databases such as Google Scholar, PubMed, PubMed Central, Science Direct, and Scopus to find relevant studies by using keywords such as “periodontium”, “periodontal ligament”, “periodontal ligament space”, “widened periodontal ligament”, and “periodontal ligament widening”.

Out of nearly 200 articles, about 60 were broadly relevant to the topic. Ultimately, 47 articles closely related to the topic of interest were reviewed. When the relevant data were compiled, the following 10 entities were identified: occlusal/orthodontic trauma, periodontal disease/periodontitis, pulpo-periapical lesions, osteosarcoma, chondrosarcoma, non-Hodgkin lymphoma, progressive systemic sclerosis, radiation-induced bone defect, bisphosphonate-related osteonecrosis, and osteomyelitis.

Although PDL widening may be encountered by many dentists during their routine daily procedures, the clinician should consider some serious related conditions as well.