Background: Tooth size-arch length discrepancy (TSALD) is a consequence of disharmony between the size of the teeth and the space available to accommodate them in the dental arches, they are manifested in the form of either crowding or spacing. Crowding is the deviation in tooth position such as rotation, overlapping, tooth emergence inside or outside the dental arch and impaction due to the lack of space. Crowding may occur due to different reasons, for example, growth, maturation, aging of dentition, mesial drift, soft tissue pressures, and tooth morphology. The correction of severe mandibular crowding could be carried out by extraction, distalization, surgical and non-surgical expansion of the mandible. Aim: The aim of this case report is to describe a novel method of non-surgical mandibular expansion. Case report: This case report demonstrates a non-surgical dentoalveolar expansion by the use of a translingual force mandibular expander appliance (‘TORKO’ Leone rapid micro expander screw) for the correction of severe mandibular crowding with posterior bilateral scissor bite in an adolescent patient with reduced inter canine and premolar width. This is a case report first of its kind which demonstrates a severe crowding case treated by an expansion device and outlines the challenges faced in achieving well stable results. Conclusion: The overall active orthodontic treatment lasted for 16 months, an expansion of 6 mm of inter-canine width is achieved. The one year follow up showed a stable mandibular arch following the treatment using TORKO appliance. Clinical significance: In this case report we have discussed the concept of increasing mandibular inter-canine width in an adolescent patient presenting severe lower anterior crowding and the factors affecting its stability.