Background: Crowding is the most frequent malocclusion in orthodontics, with a strong hereditary tendency. It already occurs in pediatric age and is mainly hereditary. It is a sign of a lack of space in the arches, and is not self-correcting, but can worsen over time. The main cause of the worsening of this malocclusion is a progressive and physiological decrease in the arch perimeter. Methods: To identify relevant studies investigating the most common possible treatments for mandibular dental crowding, a comprehensive search of PubMed, Scopus and Web of Science was conducted encompassing the last 5 years (2018–2023) using the following MeSH: “mandibular crowding AND treatment” and “mandibular crowding AND therapy “. Results: A total of 12 studies were finally included. An orthodontic treatment cannot ignore the concept of “guide arch”, which concerns the lower arch, because of the objective difficulty in increasing its perimeter; the bone structure of the lower jaw is more compact than that of the upper one. Its expansion, in fact, is limited to a slight vestibularization of the incisors and lateral sectors that may be associated with a limited distalization of the molars. Conclusions: There are various therapeutic solutions available to the orthodontist, and a correct diagnosis through clinical examination, radiographs and model analysis are essential. The decision of how to deal with crowding cannot be separated from an overall assessment of the malocclusion to be treated.