supernumerary teeth are a relatively frequent disorder of odontogenesis characterized by an excess number of teeth , with mesiodens being the most frequent.1 the term of mesiodens is used to refer to an unerupted supernumerary tooth in the midline of maxilla , between the central incisors.2,3 the incidence of mesiodens among caucasians is 0.153% for permanent teeth,4,5 and is found two times more frequently in males , compared to females.46 a mesiodens can manifest bilaterally,46 or in an inverted ( upward ) position.4,5 the frequency of inverted mesiodens constitutes to approximately 967% of all reported cases.711 to date , a total of 278 single inverted mesiodentes have been reported ( table 1 ) . the mesiodens may present a rudimentary morphology with a cone - shaped crown , generally smaller in size than the adjacent normal teeth . it may also be found to mimic a natural tooth shape .
the root is often totally formed , and may be curved or globular.12 mesiodens is frequently associated with several craniofacial disturbances , including cleft lip and palate13 and cleidocranial dysostosis;14 and to a lesser extent with gardner s syndrome or chondorectodermal dysplasia.15 only 25% of all mesiodentes spontaneously erupt into the oral cavity.6 in general , they remain impacted and asymptomatic ; and are commonly discovered during routine radiographic examination.16 the most common complications of mesiodentes are the delay or prevention of eruption ( 2652% ) and displacement / rotation ( 2860% ) of maxillary permanent incisors .
relatively less common complications include crowding , diastema , dilaceration of permanent teeth , cyst formation and eruption into the nasal cavity.6 this case reports presents radiographic features of a unique occurrence of two impacted , inverted mesiodentes in a child patient ; and the 24-month radiographic and clinical follow - up after surgical removal .
an 8-year - old boy was referred to the department of pediatric dentistry with a chief complaint of crowding in the maxillary anterior region .
being born to non - consanguineous parents , the patient s health status was excellent .
panoramic radiograph revealed the presence of two supernumerary teeth , located between the roots of the permanent central incisors ( figure 2 ) .
occlusal and periapical radiographs of the region showed that these two teeth were inverted mesiodentes ( figure 3 ) .
apparently , the roots of the permanent central incisors had migrated distally , owing to the presence of the supernumerary teeth .
the lateral cephalogram showed that the mesiodentes were located buccally to the apices of the central incisors ( figure 4 ) . the treatment plan consisted of surgical removal the inverted mesiodentes .
the teeth were removed under general anaesthesia without any complication ( figure 5 ) . following removal of sutures one week later , the patient was scheduled for bimonthly recalls . at the second - month recall ,
the extraction cavities were completely filled with bone ( figure 6 ) and the permanent central incisors responded favorably to thermal and electrical pulp tests .
removal of the inverted mesiodentes had slightly aided to self - correction of the axial rotations of the central incisors .
although mesiodentes are often located palatally,2 the present case demonstrates the possibility of their occurrence in a more vestibular location .
in addition to routine ortopantomography or periapical / occlusal radiographs which can rapidly solve the initial diagnostic phase of mesiodentes , further techniques may be required to better define their position in relation to the adjacent teeth and anatomic structures . in the present case , the exact route ( i.e. , buccal / palatal ) for surgical removal of the inverted mesiodentes
undoubtedly , greater detail concerning their location could be obtained through computerized axial tomography ( cat),17 which also can help evaluate their relationship with the adjacent tooth structures . in this
regard , periapical and occlusal radiographs were used in conjunction with the lateral cephalogram , since cat was not available in our centre .
extraction is not the only treatment choice for impacted mesiodentes . if the mesiodens remains in place without symptoms and does not adversely affect the adjacent teeth , it may be left in place and observed periodically.16 in the present case , surgical removal of the mesiodentes was judged necessary , since these teeth had caused axial rotation of the permanent central incisors .
there are no precise indications concerning the ideal time for surgical removal of impacted mesiodens . according to atwan,18 a mesiodens
can be best removed when the permanent central incisors start to erupt , but this may not be always possible .
contrary , primosh19 discourages early extraction of mesiodentes due to the risk of iatrogenic damage to the developing adjacent permanent teeth . in the present case ,
the timing for surgical removal of the inverted mesiodentes was judged to be suitable , since both maxillary central incisors had totally erupted , showing complete root formation and advanced apical closure .
the case presented herein was considered to be extremely rare , since inversion of two mesiodentes in a single patient has only been reported once20 ( table 1 ) .
the clinical significance of the inversion is questionable , since both mesiodentes remained intact ; i.e. , did not erupt ectopically .
however , the occurrence of two mesiodentes was definitely regarded as a contributory factor to the crowding in the anterior maxillary region , as evidenced by the deviation in the vertical axis of both central incisor teeth .
fortunately , the post - surgical phase was uneventful , and did not affect commencement of fixed orthodontic therapy after a relatively short follow - up period .
 this report presents an extremely rare occurrence of two inverted mesiodentes in a child patient . 
 extraction of both mesiodentes was indicated , owing to the axial rotation of the permanent central incisors caused by these impacted supernumerary teeth . 
 radiographic evidence of complete healing was observed 24 months following surgical removal of the inverted mesiodentes . 
INTRODUCTION
CASE REPORT
DISCUSSION