ABSTRACT
Background: Crowding, rotation and impaction of teeth are some of the complications of supernumeraries. This
article aims to discuss the orthodontic treatment of a severely rotated upper left central incisor (UL1) secondary
to an erupted mesiodens. An 18-year old Malay male presented with Class I malocclusion with severely crowded
upper arch, presence of erupted mesiodens, severely rotated upper left central incisor, displaced upper left lateral
incisor and upper left canine and centreline discrepancy. Methods: He had a combination of segmented arch
and couple force mechanics to correct severely rotated central incisors. Following anchorage reinforcement, the
upper mesiodens and the upper right first premolar was extracted. Subsequently, treatment was continued with
conventional straight wire mechanics. Results: The severely rotated upper left central incisor was successfully
corrected, and the upper arch crowding was resolved. The fixed appliances were debonded and he was provided
with upper dual retention. He had gingival recession Type 1 at UL2 due to the bony defect. Conclusion: Severe
crowding can be managed with segmented arch mechanics without any detrimental effects using low forces and
good planning. Further periodontal consultation and management were required for the treatment of UL2.