Crowding of teeth is considered as the most common type of malocclusion, which is one of the most frequent reasons why people consult an orthodontist, taking into account the high aesthetic demand expressed by patients. Therefore, it is useful to know the contributing factors of dental crowding for the planning of orthodontic treatment and achieving stability in retention. Lately, the most frequently asked questions which are important to the clinical orthodontics are the following: What is the relationship between third molars and lower incisor crowding and if there any explanation how to act with third molars at the end of orthodontic treatment? The results of the present study have shown substantial evidence to assert that third molars are a contributing factor for lower arch crowding. Therefore, there was a strong relationship between lower arch dimensions, angulation and position of third molars and lower arch.