Address for correspondence:

J. COHEN-LEVY,255, rue Saint-Honore, 75001 Paris.juliacohenlevy@yahoofrance

DOI: 10.1051/odfen/2011107 J Dentofacial Anom Orthod 2011;14:108� RODF / EDP Sciences

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R A D I O ‘ ‘ L O G I C A L ’ ’ R E F L E C T I O N S

Idiopathic resorption?

Julia COHEN-LEVY

A CASE PRESENTATION

We have been following 13 year-oldJessica since she was 9 years old becauseof an arch length discrepancy with an AngleClass I relationship, on a thin periodontalbiotype. Because of the severity of hermandibular crowding, we had discussedbeginning a program of serial extractions(fig. 1 a and b).

Jessica demonstrated no particular signsof previous malfunctions, her breathing was

uniquely nasal, her swallowing was mature,and the absence of muscular signs and dentalwear facets indicated there had never beenperiods of bruxism, nor were there any signsof pencil chewing or nail biting.

Her lingual frenum was short, whichtended to keep her tongue in a low postureand her upper labial frenum was also in alow position causing a midline diastema.When we took an occlusal photograph, the

Figures 1 a and bIntraoral views of the maxilla and mandible before treatment. Note the severe crowding of the mandibular incisors.

Article available at http://www.jdao-journal.org or http://dx.doi.org/10.1051/odfen/2011107

frenum caused withening of the mu-cosa, a typical sign of insertion on thegingival papilla.

This young patient had neversucked her thumb or fingers andreported no history of even the slight-est oral trauma. She was receiving no

medical treatment and was in excel-lent health.

The patient is now ready to begintreatment to align her teeth with theoriginally planned full banded andbonded appliance.

DESCRIPTION OF THE RADIOGRAPHIC RECORDS

Our X-ray file for Jessica containedthree consecutive panoramic films,two lateral cephalograms, and sec-tional images taken with the conebeam technique.

Diagnostic documents

The panoramic film (fig. 1 c) showsclearly that all unerupted teeth arepresent with the exception of thebuds of the third molars, which in-dicates a dental age of 8 or 9 year-old.The upper lateral incisors are slightlylate in their eruption, and still quiteincompletely formed and rotated intheir axial positions.

The buds of the lower canines aremesially inclined, the left quitestrongly, and the buds of the uppercanines are in a markedly high posi-tion.

The apex formation of the upperincisors is incomplete and the pulpchamber of the upper left centralincisor appears to be enlarged.

The profile head film (fig. 1 d)showed that Jessica’s upper airways

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Figure 1cView at the beginning of treatment.

Figure 1 dProfile cephalogram taken at the beginning of treat-ment. One can see the hypertrophied lymphoid tissue,which is normal at this age. The position of the incisorsand the support they give the lips appear to be inbalance.

JULIA COHEN-LEVY

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were fully open, with adenoidalgrowth normal for her age, a harmo-nious cutaneous profile that allowedfor ready spontaneous lip closure, andupper and lower incisors in goodrelationships.

Continuation of treatment(fig. 2)

After the temporary canines wereextracted, the lateral incisors eruptedinto good alignment spontaneously.Our treatment plan called for removalof the first temporary molars and,later, the permanent first bicuspids,as soon as we had observed thecanines had assumed a good position,and the presence of third molar budshad been confirmed. The crypts of theupper left third molar and both lowerthird molars can already be seen in thepanoramic film depicted in figure 2.Although their roots are short, theapices of the upper central incisorshave calcified. The upper lateral inci-sors appear to have a more normalmorphology.

We put no anchorage in placebecause we did not want to get alingual repositioning of the incisors.

Check-up visit beforeplacement of a full bandedand bonded appliance (fig. 3a to d)

X-ray films taken at this timeshowed severe resorption of the rootsof the maxillary central incisors eventhough the patient had worn neitherremovable nor fixed orthodontic appli-ances. These teeth responded posi-tively to pulpal vitality tests, showed ablurred image of their roots on thepanoramic film, and seemed to bedefinitely shortened and retroclined asviewed on the profile head film.

In view of the increased radiolucentquality of the premaxillary region, torule out any possibility of a tumorousgrowth being responsible for thesevere resorptions, panoramic anddento-axial reconstructions of theteeth were made from the cone beamradiographs (fig. 3 e and f).

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Figure 2View during treatment.

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They clearly demonstrate the se-vere resorption of the root of theupper right incisor (sections 22-24)and of the root of the upper left incisor(sections 30 to 33), both of which arejammed into cortical bone. In sections22 and 31 one can make out thephantom outlines of the former rootcanal extending 2 to 3 mm beyond theexisting blunted apex. The resorbed

roots have retained their roundedform, the gaps left by the resorptionfilled in by new bone formation analo-gous to the surrounding bone.

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Figures 3 a and bMaxillary and mandibular intraoral check-up photographs. Note how the incisor teeth got spontaneously aligned witha residual space left from the bicuspid extraction. On the right side these spaces are closing as the second molars areerupting. The lower incisors can be seen located near the buccal aspect of the mandibular symphysis with a thingingiva.

Figure 3 cPanoramic check-up film before placement of appli-ances.

Figure 3 dCheck-up profile cephalogram before placement ofappliance.

JULIA COHEN-LEVY

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Figure 3 eReconstructions made with the cone beam technique: axial sections and curvilinear panoramic reconstructions.

Figure 3 fAxial reconstructions of the teeth.

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WHAT DIAGNOSIS DOES THE DATA SUGGEST?

Both biological and mechanical fac-tors influence the development ofexternal root resorption, a frequentlyoccurring phenomenon.

When the process destroys morethan one third of the root it can becalled severe. And when it appears oncheck-up X-rays films of patients whohad displayed no clinical signs indicat-ing its development, it causes graveconcern to treating orthodontists.

In this patient the root/crown ratiowas initially close to 1 to 1 (see thecheck-up X-ray taken just after the rootapex had calcified) and now the crownis twice the size of the root, makingthis a case of extreme root resorption.

There are many known and loca-lized causes for root resorption, noneof which seemed to be relevant forthis patient, unless the slightly atypicalmorphology of the central incisors canbe considered an etiological factor.

The patient’s general health wasgood with no indications of hormonal,allergic, inflammatory, or nutritionalproblems. Nor were there any difficul-ties with her phosphorous and calciummetabolism.

Locally, there were no signs of oraldysfunction or gingival inflammation.And even after our most persistentand inquisitive interview we couldunearth no past history of oral trauma.

The mechanical factors associatedwith root resorption occurring duringthe course of orthodontic treatmentare those that concentrate forces on

root apices through wide rangingtooth movement, application of roottorque, and tooth intrusion. But thispatient had never worn an orthodonticappliance. Only an anterior overbite,gradually developing concurrent withan increase in the lingual inclination ofthe incisor teeth could be consideredan occlusal overload.

We asked ourselves a variety ofquestions about the etiology of theseroot resorptions. Had there been anold ‘‘forgotten’’ traumatic incident?Did this patient have some kind ofgenetic susceptibility? In taking med-ical histories of the child’s parents wefound that the mother had congeni-tally absent maxillary lateral incisors.But no clear etiological explanationemerged.

We could put a name on it, idio-pathic resorption.

The adjective idiopathic comes fromthe Greek idios, which means, parti-cular, specific and from another Greekword, pathos, from which we getpathology and other medical terms.Pathos is a synonym for suffering oraccidental change. An idiopathic mala-dy may occur in association withanother disorder, or pathosis, butnevertheless has its own develop-ment and its own characteristics. Inpractical terms, it describes a diseaseentity whose causation is unknownand that would be more correctlydescribed as cryptogenic.

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WHAT STANCE SHOULD WE ADOPT IN REGARD TO THIS PROBLEM ANDWHAT WOULD BE ITS EFFECT ON FUTURE ORTHODONTIC TREATMENT?

We have postponed beginning fullbanded and bonded finishing ortho-dontic treatment for this patient be-cause of the risk of accelerating thepathological resorption process.

With the goal of lending support toJessica’s upper central incisors,which, by themselves bear the fullburden of protrusive mandibular ex-cursion movements (see fig. 4 a andb) and also to protect against possibleeccentric nocturnal bruxism, wedecided it would be prudent to con-struct a temporary occlusal splint for

her to wear at night, that would beslightly spaced in relation on thecentral incisors.

Even in cases of idiopathic resorp-tions, we can suspect a real etiolo-gical factor in the form of micro-trauma working on a predisposedsite or of vaso-motor disturbances.With the splint, we hope we areprotecting Jessica against thesepossible threats by giving her inci-sors respite against all inflammatorystimuli from pressure that couldexacerbate her condition.

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Figure 4 aFrontal intraoral photograph of teeth in occlusion.

Figure 4 bIntraoral photograph of the mandible in propulsion.The central incisors are the only teeth in contact.

Figure 4 c‘‘Decompression’’ splint for the upper centralincisors.

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No endodontic treatment is indicated.Even though the affected teeth do

not yet show any signs of worrisomemobility, we have informed the patientand her family that there is a risk ofher losing her upper central incisorsand that they will have to be replacedby implants at the end of her growthperiod.

Jessica has been keeping her check-up appointments faithfully and we areconsidering a future sectional treat-ment, assiduously avoiding the inci-sors, once her second molars have fullyassumed their positions in the dentalarches.

WORKS TO CONSULT

Chouvin M. Relation entre phase de traitement, pulsion linguale et l’apparition desresorptions radiculaires. Orthod Fr 1995;66:559–566.Frapier L, Massif L, Leplus M, Chouvin M, Canal P. Conduite a tenir face aux resorptionsradiculaires. Rev Orthop Dento Faciale 2007;41:295–309.Kjaer J. Morphological characteristics of dentitions developping excessive root resorptionduring orthodontic treatment. Eur J Orthod 1995;16:25–34.Samadet V. Entretien avec Pierre Machtou : a propos des resorptions radiculaires liees autraitement d’orthopedie dentofaciale. Rev Orthop Dento Faciale 2007;41:253–262.Samadet V, Bacon W. Les resorptions radiculaires : facteurs de risque et attitudestherapeutiques. Rev Orthop Dento Faciale 2007;41:263–293.

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