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This paper reports the management of two clinical cases, in which the upper right central incisor was fused with a supernumerary tooth and the upper left central incisor was macrodontic. A radiographic examination revealed that the fused teeth had two separate roots. Hemisectioning of the fused teeth was performed, the supernumerary portion was extracted and the remaining part was reshaped to remove any sharp margins and to achieve a normal morphology. The macrodontic central incisors were not treated. At 12-months post-surgery there were no periodontal problems and no hypersensitivity. Orthodontic treatment was performed to appropriately align the maxillary teeth and to correct the malocclusion.
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Fused upper central incisors: management of two clinical cases
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Fused upper central incisors: management of two clinical cases
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                                                                                                                     Case report



    Fused upper central incisors:
    management of two clinical cases




                                                                                                                   li
                                                                                                                na
    Gian Luca Sfasciotti, MD, DDS, PhD                               a systemic disorder, and affects mainly the upper central
    Roberta Marini, DDS                                              incisors if it derives from a partial defect. The prevalence
    Maurizio Bossù, DDS, PhD                                         of macrodontia is calculated as 0.03% and there is no sex




                                                                                                             io
    Gaetano Ierardo, DDS, PhD                                        preference (3).
    Susanna Annibali MD, DDS                                         Several approaches to the treatment of this condition have
                                                                     been reported in the dental literature, such as restoring the




                                                                                      az
                                                                     crown shape or prosthetic treatment for esthetic reasons,
                                                                     or extracting the tooth for orthodontic or periodontal
    “Sapienza” University of Rome, Rome, Italy                       complications.
    Department of and Maxillofacial Sciences                         Fusion and germination are tooth shape abnormalities (1)
                                                                     that are often described using the terms “double teeth”,




                                                                                    rn
                                                                     “double formations”, “joined teeth” and “dental twinning”.
    Corresponding author:                                            Fusion is the union of two or more dental germs, and can
    Dott. Gian Luca Sfasciotti                                       involve the permanent, primary or supernumerary denti-
    Via Famiano Nardini 1/e                                          tion. Depending on the developmental stage at the time




                                                                         te
    00162 Rome, Italy                                                of union, fusion may be incomplete, involving only the to-
    Phone/Fax +39068610788                                           oth crowns, or complete, involving both the crowns and ro-
    E-mail: gianluca.sfasciotti@uniroma1.it                          ots. Clinically the fused tooth usually has a wide crown and
                                                                 In  two independent root canals or, less often, a single root
                                                                     and one or two pulp chambers (4). The crown may exhi-
                                                                     bit an incised notch, a bifid aspect or an enamel groove
    Summary                                                          between the medial and distal parts, which can extend to
                                                                     the root surface. The maxillary central incisors are the te-
                                                    ni
    This paper reports the management of two clinical                eth that are most often affected. The prevalence of dou-
    cases, in which the upper right central incisor was fused        ble teeth differs between studies, ranging from 0.05% to
    with a supernumerary tooth and the upper left central in-        5% in permanent dentition (2) and 0.7% in deciduous den-
                                          io


    cisor was macrodontic. A radiographic examination re-            tition (5). The discrepancy is probably due to racial and geo-
    vealed that the fused teeth had two separate roots.              graphical differences in the population studied, variable
    Hemisectioning of the fused teeth was performed, the             sampling techniques and different diagnostic criteria
    supernumerary portion was extracted and the remain-
                                 iz



                                                                     (1,6,7).
    ing part was reshaped to remove any sharp margins and            Germination is considered to be incomplete division of a
    to achieve a normal morphology. The macrodontic cen-             single tooth germ, starting at the incisal edge and abor-
    tral incisors were not treated. At 12-months post-surgery        ting before cleavage is complete. Clinically, a germinated
                 Ed




    there were no periodontal problems and no hypersensi-
                                                                     tooth is characterized by a bifid crown with a single root
    tivity. Orthodontic treatment was performed to appro-
                                                                     and a single or partly divided pulp space (3).
    priately align the maxillary teeth and to correct the
                                                                     The aetiology and pathogenesis of fusion and germination
    malocclusion.
                                                                     remain unclear. It was assumed that trauma, heredity, ge-
    Key words: fusion, fused tooth, macrodontia, hemisec-            netic predisposition and environmental factors, such as foe-
    tion, supernumerary tooth.                                       tal alcohol exposure, thalidomide embryopathy and hy-
 IC




                                                                     pervitaminosis A of the pregnant mother, may play a role
                                                                     in the formation of double teeth (3,6). Double teeth may
    Introduction                                                     also be part of certain syndromes, such as chondroecto-
                                                                     dermal dysplasia, achondrodysplasia, otodental dyspla-
C




    Developmental dental anomalies include abnormalities in          sia, focal dermal dysplasia and osteopetrosis (3,8,9,10).
    tooth size (microdontia and macrodontia), shape (fusion,         Double teeth usually occur in the anterior region of the jaws
    germination and concrescence), number (anodontia, oli-           and cause aesthetic, periodontal, functional and orthodontic
    godontia, hypodontia and hyperdontia) and structure              problems, such as diastema, crowding, protrusion, im-
©




    (amelogenesis imperfect and dentinogenesis imperfecta),          paction or ectopic eruption of the adjacent teeth (11,12).
    which are all the result of local and systemic factors that      Several treatment methods have been described in the li-
    affect the initial morphological differentiation stage of den-   terature according to the different types and morphologic
    tal germs (1,2).                                                 variations of anomalous teeth. However the treatment of
    Macrodontia is a rare abnormality in tooth size that ma-         double teeth requires a multidisciplinary approach to achie-
    nifests clinically as a tooth of normal morphology but of unu-   ve ideal functional and aesthetic results.
    sually larger size, with a single root and pulp chamber (4).     Herein we describe the treatment of two patients with den-
    This anomaly involves the entire dentition if it derives from    tal fusion and macrodontia involving the central incisors.

    40                                                                                   Annali di Stomatologia 2011; II (3-4): 40-44
    Fused upper central incisors: management of two clinical cases


    Clinical cases

    Case 1
    An 8-year-old Italian boy was referred to the Paediatric Den-
    tistry Unit of the Department of Oral and Maxillofacial Scien-
    ces, “Sapienza” University of Rome, with a complaint in-




                                                                                                                        li
    volving the right maxillary permanent central incisor.
    There was no history of dental anomalies, systemic di-




                                                                                                                     na
    seases or dental trauma. A clinical examination (Fig. 1) re-
    vealed the following:
    1. The right permanent central incisor had a bifid crown
         and had erupted buccal to the primary lateral incisor;




                                                                                                                  io
    2. The right permanent lateral incisor had erupted in the
         oral position due to insufficient space;
    3. The crown of the left permanent central incisor had             Figure 2 - Case 1. Orthopantomograph.
         a normal morphology but was abnormally large (ma-




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         crodontia);
    4. A diastema of 3 mm between the central incisors;
    5. The normal number of teeth.




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                                                                           te
                                                                   In
                                                     ni

                                                                       Figure 3 - Case 1. Computed tomography scan.
    Figure 1 - Case 1. Intraoral photograph.
                                            io


    The response to thermal pulp testing and the periodontal
                                   iz



    probing of the permanent central incisors were normal. The
    patient was in the mixed dentition stage with a class I mo-
    lar relationship on the basis of Angle’s classification.In-
                  Ed




    creased overjet, increased overbite and anterior lower den-
    tal crowding were also present.
    A radiographic evaluation involving orthopantomography
    and computed tomography (Dentascan) indicated that the
    right central incisor had two distinct roots and two sepa-
    rate endodontic spaces, and that the left central incisor had
    a large pulp chamber and one root canal and macrodon-
 IC




    tia of the left central incisor (Figs. 2 and 3). The therapeutic
    options were discussed with the patient and his parents,
    and sectioning of the fused tooth was planned.
    Under local anaesthesia (mepivacaine 2% with adrenalin
C




    1:100,000), the right primary lateral incisor was extracted,
    and a mucoperiosteal flap, extended from the left per-
    manent central incisor to the right primary canine, was rai-
    sed until the whole crown of the anomalous tooth was ex-
©




    posed. The fused tooth was separated along the enamel
    groove, using a high-speed dental hand-drill and a diamond
    bur, and the mesial portion (supernumerary) was extrac-
    ted (Figs. 4 and 5). The flap was sutured with 3-0 non-ab-
    sorbable silk sutures (Ethicon) and the crown of the right
    maxillary central incisor was redefined with a flame-sha-
    ped finishing bur. Reshaping of the crown was necessa-
    ry to remove the sharp margins and to establish an ana-            Figure 4 - Case 1. Sectioning the tooth.


    Annali di Stomatologia 2011; II (3-4): 40-44                                                                      41
    G.L. Sfasciotti et al.




                                                                                                                          li
                                                                                                                       na
                                                                                                                    io
    Figure 5 - Case 1. The extracted right primary lateral incisor and   Figure 7 - Case 2. Intraoral photograph.
    supernumerary tooth.




                                                                                           az
    tomy consistent with a normal central incisor.                       I molar relationship and normal overjet. Upper dental crow-
    An orthodontic device (DAMON type MX3) was applied to                ding was present and the overbite was decreased, with a




                                                                                         rn
    allow realignment of the central and lateral incisors and re-        tendency to an open bite.
    solution of the malocclusion (Fig. 6). At the 8-month post-          Periapical radiographs of the upper central incisors (Fig.
    surgery recall, the right maxillary central incisor exhibited        8) indicated that the right one had two separate roots, two
    healthy gingival tissues, no increase in probing depth and           pulp chambers and a single bifid crown and that the left




                                                                             te
    a positive response to pulp testing.                                 one had a single root and one pulp chamber. The diagnosis
                                                                         was fusion of the right central incisor with a supernume-
                                                                         rary tooth and a macrodontic left central incisor.
                                                                     In
                                                       ni
                                            io
                                   iz



    Figure 6 - Case 1. Intraoral view at 8-months post-surgery.
                  Ed




                                                                         Figure 8 - Case 1. Periapical radiographs of the right (a) and left
                                                                         (b) side.
    Case 2
    An 8-year-old Italian boy was referred to the Paediatric Den-
    tistry Unit of the Department of Oral and Maxillofacial Scien-       Surgical sectioning and extraction of the distal part of the
    ces, “Sapienza” University of Rome, with an anomaly of               fused tooth was scheduled to facilitate orthodontic repo-
 IC




    the right maxillary permanent central incisor. His medical           sitioning of the lateral incisor. The left central incisor was
    history was negative for systemic diseases, dental trau-             left untreated. The treatment plan was explained to the pa-
    ma and familial history of dental anomalies. An intraoral            tient and his family and informed consent was obtained.
    examination revealed the following in the upper arch (Fig.           Before surgery, a fixed orthodontic device (Mc Laughin-
C




    7):                                                                  Bennett-Trevisi) with 013 wire and elastic low friction li-
    1. A right central incisor had a bifid crown and was de-             gatures (CuNiTi) was applied to facilitate repositioning of
         lineated by an enamel groove;                                   the teeth.
    2. A wider than normal left central incisor;                         Under local anaesthesia (mepivacaine 2% with adrenalin
©




    3. A diastema of 4 mm between the central incisors;                  1:100,000), the tooth crown was sectioned was performed
    4. A right lateral incisor that had erupted buccally due to          following the groove in the enamel, using a diamond cy-
         insufficient space;                                             lindrical bur under saline irrigation, and the distal portion,
    5. The normal number of teeth.                                       aligned with the supernumerary, was extracted using a
    Both of the central incisors exhibited positive responses            straight elevator. The remaining tooth was reshaped to re-
    to thermal pulp testing, were asymptomatic to percussion             move the sharp edges and to improve the coronal mor-
    and had no periodontal pockets on probing.                           phology (Fig. 9). Compression was applied for a few mi-
    The patient was in the mixed dentition stage with a class            nutes using wet gauze to control the bleeding.

    42                                                                                         Annali di Stomatologia 2011; II (3-4): 40-44
    Fused upper central incisors: management of two clinical cases


                                                                      and supernumerary teeth. Levitas suggested that the num-
                                                                      ber of teeth in the arch should be counted whilst considering
                                                                      the anomalous crown as a single tooth: fusion decreases
                                                                      this number and germination does not (13). This diagno-
                                                                      stic criterion becomes untrustworthy either when the fu-
                                                                      sion involves a supernumerary tooth, because the num-




                                                                                                                    li
                                                                      ber of teeth is not reduced, or when germination is asso-
                                                                      ciated with agenesis (3).




                                                                                                                 na
                                                                      In the two cases presented here diagnosing fusion between
                                                                      the central incisor and a supernumerary tooth was not dif-
                                                                      ficult, not only because of the normal number of elements
                                                                      in the arch, but also because of the coronal morphology,




                                                                                                              io
                                                                      which was characterized by a groove separating the crown
                                                                      into two components, and the presence of two separate
                                                                      roots.
                                                                      The diagnosis of the macrodontic tooth which had a sin-




                                                                                       az
                                                                      gle large-than-usual crown, one root and a single pulp
                                                                      chamber was more difficult because it was possible that
                                                                      this element could have represented either macrodontia
                                                                      or complete fusion with a supernumerary in the early sta-




                                                                                     rn
                                                                      ge of the morphological differentiation of the tooth germ.
                                                                      The association in the same dentition between fused te-
                                                                      eth at one site and a macrodontic tooth at another site has
                                                                      been reported by several authors (3,4,6).




                                                                          te
                                                                      However the difficulty in differentiating between fusion, ger-
                                                                      mination and macrodontia does not affect the choice of tre-
                                                                      atment plan, and is rather determined by the type of den-
                                                                      tition, the crown morphology, the root and endodontic ana-
                                                                    Intomy, and the orthodontic (diastema, crowding or protru-
    Figure 9 - Case 2. Intraoral view of the tooth crown before (a)   sion), periodontal and aesthetic requirements of the pa-
    and after (b) extraction of the mesial portion (supernumerary).   tient.
                                                                      Several treatments have been proposed in the literature
                                                                      to solve the problems related to an abnormally large ele-
                                                     ni

                                                                      ment. In deciduous dentition, double or macrodontic teeth
    After the surgical treatment, fixed orthodontic treatment was     do not require therapy unless they interfere with the erup-
    continued in the patient to align the teeth in the arch and       tion of the homologous permanent dentition, in which case
                                            io


    to correct the malocclusion (Fig. 10). At the follow-up exa-      extraction is necessary (14). As for permanent dentition,
    minations performed at 3, 6 and 12-months post-surge-             there are four types of approaches for fusion and germi-
    ry, the right central incisor had a positive response to ther-    nation:
                                   iz



    mal pulp testing and no periodontal pockets were obser-           1. Extraction in cases where the roots are not separated
    ved on probing.                                                        and no endodontic treatment is possible;
                                                                      2. Separation into two single units when the fusion
                  Ed




                                                                           is between two permanent teeth with two separate ro-
                                                                           ots or if it is possible endodontic treatment if possible
                                                                           (9,15);
                                                                      3. Hemisectioning and extraction of one tooth portion
                                                                           when the fusion is between a permanent and a su-
                                                                           pernumerary tooth with two distinct roots or endodontic
                                                                           treatment if possible (10,12,16);
 IC




                                                                      4. Reshaping of the crown.
                                                                      In the present cases, fusion of the right central incisors with
                                                                      a supernumerary and the macrodontic left central incisors
                                                                      required two different approaches. The right central inci-
C




                                                                      sors, with two roots and two independent endodontic spa-
                                                                      ces, were surgically separated without endodontic treat-
                                                                      ment, and the supernumerary tooth was extracted to al-
                                                                      low correct alignment of the dental arch. The macrodon-
©




    Figure 10 - Case 2. Intraoral view at 12-months post-surgery.     tic left central incisors, characterized by a single root and
                                                                      single pulp, did not require any kind of therapy.
                                                                      Hemisectioning of the abnormal teeth was perfor-
                                                                      med under visual control: in case 1 it was necessary to rai-
    Discussion                                                        se a flap to expose the division of the roots, while in case
                                                                      2 it was sufficient to section the crown using the ena-
    Differentiating between fusion and germination can be dif-        mel groove as a guide (14). During the hemisectioning pro-
    ficult, especially when fusion occurs between permanent           cedure, every effort was made to remove the tooth struc-

    Annali di Stomatologia 2011; II (3-4): 40-44                                                                                  43
    G.L. Sfasciotti et al.


    ture only at the expense of the supernumerary part of the                 case report. Pediatr Dent. 2006 ;28(4):336-40.
    tooth.                                                                 5. Wu CW, Lin YT, Lin YT. Double primary teeth in children un-
    The dislocation and extraction of the dental fragment were                der 17 years old and their correlation with permanent suc-
    performed with delicate movements. The elevator was                       cessors. Chang Gung Med J. 2010;33(2):188-93.
                                                                           6. Mattos-Graner RO, Rontani RM, Gavião MB, de Souza Fil-
    not inserted into the space between the two portions and
                                                                              ho FJ, Granatto AP, de Almeida OP. Anomalies of tooth form
    force was applied only against the portion that was being




                                                                                                                            li
                                                                              and number in the permanent dentition: report of two cases.
    extracted in order to preserve the remaining part.                        ASDC J Dent Child. 1997;64(4):298-302.
    More important for treatment outcome is periodic and long-




                                                                                                                         na
                                                                           7. Guimarães Cabral LA, Firoozmand LM, Dias Almeida J. Dou-
    term follow-up to check pulp vitality and periodontal health,             ble teeth in primary dentition: report of two clinical cases. Med
    since some authors have reported that the sectioning pro-                 Oral Patol Oral Cir Bucal. 2008;13(1):E77-80.
    cedure may cause pulp disease as a result of exposing va-              8. Karaçay S, Gurton U, Olmez H, Koymen G. Multidisciplina-
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                                                                                                                      io
    shared between the two roots (10,11,17).                                  J Dent Child (Chic). 2004;71(1):80-6.
                                                                           9. Olivan-Rosas G, López-Jiménez J, Giménez-Prats MJ, Pi-
                                                                              queras-Hernández M. Considerations and differences in the
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                                                                                            az
                                                                          10. Cetinbas T, Halil S, Akcam MO, Sari S, Cetiner S. Hemisec-
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                                                                              diol Endod. 2007;104(4):e120-4.
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                                                                                          rn
    The choice of the appropriate treatment plan should be de-                Oral Pathol Oral Radiol Endod. 2011 May;111(5):649-52. Epub
    termined by the morphology and the endodontic anatomy                     2011 Feb 18.
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                                                                              te
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                                                                          13. Levitas TC. Gemination, fusion, twinning and concrescence.
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        tral incisor in association with a macrodont lateral incisor: a       report. Dent Traumatol. 2008;24(5):e34-7. Epub 2008 Jun 28.
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    44                                                                                           Annali di Stomatologia 2011; II (3-4): 40-44
