Introduction:
Double tooth is a general word commonly used to describe either fusion or gemination 1. The literature showed prevalence estimates for bilateral double teeth ranging from 0.01% to 0.04% in the primary dentition, and 0.05% in the permanent dentition. Differential diagnosis between these two anomalies can be challenging, however tooth count is always the first step 2. In gemination tooth count is normal while in fusion the number of teeth is one fewer unless it happens between a supernumerary tooth and a normal one 3, 4.
These anomalies could lead to higher caries potential, malocclusion, changes in the dental arch shape, periodontal disease, hyper /hypodontia, and poorer esthetics. Treatment options include restorative treatment (35%), hemisection (33%), extraction (15%) and no intervention (17%) based on violaine’s report 5. Orthodontic treatment has been reported to be a main or alternative option in 57% of the cases with double teeth anomaly5, 6.
Animal studies 7 and case reports8-10 have shown that movement of the teeth across the midpalatal suture (MPS) is biologically possible however it always offers a unique challenge for the orthodontists. The main considerations are root resorption and frenum inflammations9. Jason pin in 2011 represented a case of bilateral gemination in which they extracted the right incisor and moved the left one 3 mm across the suture to correct the midline10 . In their case the geminated tooth had smaller widths compared to a normal one10. Garib (2012) also reported a case that the right incisor moved through the suture to replace the absent contralateral tooth 8. In both cases frenectomy has been done to decrease the inflammation of stretched frenum, also, to decrease the chance of relapse. However no major root resorption was reported by any of those studies. In this study a rare case of moving a bi-rooted fused central incisor across the MPS is presented.
Case presentation
A 10-year-old male patient presented to the orthodontic department of Shahid Sadoughi University of Medical Sciences with the main complaint of enlarged front teeth. The patient was the first of 3 siblings of parents with no history of consanguinity. The patient appeared normal and healthy with no reported history of orofacial trauma.