Root resorption is the loss of dental hard tissue as a re-sult of clastic activities.1 The dental hard tissue of perma-nent teeth does not normally undergo resorption. The clas-sification of root resorption plays an important role forthe clinician in the processes of diagnosis and treatmentplanning. Tooth resorption may be described according tolocation as internal or external resorption. External rootresorption can be further classified into surface resorp-tion, external inflammatory resorption, external replace-ment resorption, external cervical resorption, and transientapical breakdown.2 Some local factors cause external re-sorption, such as impacted teeth, orthodontic treatment,tumors and cysts, luxated or reimplanted teeth, periradic-ular inflammatory lesions, periodontal disease, and toothbleaching. Systematic disorders including hypoparathy-roidism, hyperparathyroidism, calcinosis, Turners syn-

drome, Gauchers disease, and Pagets disease have alsobeen reported as the causative factors of external root re-sorption.3

Internal root resorption can be classified into internalinflammatory resorption and internal replacement resorp-tion.4 Although the etiology and pathogenesis of internalresorption is not fully understood, it is generally causedby chronic infection or trauma,5 and radiographically, in-ternal resorption appears as a well-demarcated, round-to-oval radiolucent widening or ballooning out of the pulpalroot canal that is continuous with the walls of the canalitself on the radiograph.2,6

There are also some rare cases of tooth resorption of anunknown cause that do not fit into any of the above cat-egories; they are usually named idiopathic root resorp-tion.7

Two types of idiopathic root resorption have been ob-served: apical and cervical. Cervical root resorption beginsat the cervical area of a tooth and progresses towards thepulp, whereas apical root resorption affects the apical por-tion of the tooth root and causes gradual shortening.8 The

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Multiple idiopathic external and internal resorption: Case report with cone-beam computedtomography findings

Berkan Celikten1,*, Ceren Feriha Uzuntas1, Hakan Kurt2

1Department of Endodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey2Department of Dento-Maxillo-Facial Radiology, Faculty of Dentistry, Ankara University, Ankara, Turkey

ABSTRACT

Root resorption is loss of dental hard tissue as a result of clastic activities. The dental hard tissue of permanent teethdoes not normally undergo resorption, except in cases of inflammation or trauma. However, there are rare cases oftooth resorption of an unknown cause, known as idiopathic root resorption. This report would discuss a rare caseof multiple idiopathic resorption in the permanent maxillary and mandibular teeth of an otherwise healthy 36-year-old male patient. In addition to a clinical examination, the patient was imaged using conventional radiography andcone-beam computed tomography (CBCT). The examinations revealed multiple external and internal resorption ofthe teeth in all four quadrants of the jaws with an unknown cause. Multiple root resorption is a rare clinicalphenomenon that should be examined using different radiographic modalities. Cross-sectional CBCT is useful inthe diagnosis and examination of such lesions. (Imaging Sci Dent 2014; 44: 315-20)

KEY WORDS: Cone-Beam Computed Tomography; Endodontics; Tooth Resorption

Received April 6, 2014; Revised June 5, 2014; Accepted July 9, 2014*Correspondence to: Dr. Berkan CeliktenDepartment of Endodontics, Faculty of Dentistry, Ankara University, Besevler,Ankara 06560, TurkeyTel) 90-312-296-56-23, Fax) 90-312-212-39-54, E-mail) berkancelikten@yahoo.com.tr

Imaging Science in Dentistry 2014; 44: 315-20http://dx.doi.org/10.5624/isd.2014.44.4.315

Copyright 2014 by Korean Academy of Oral and Maxillofacial RadiologyThis is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0)

which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Imaging Science in DentistrypISSN 2233-7822 eISSN 2233-7830

most common clinical feature of idiopathic root resorp-tion is that patients are generally asymptomatic with anoccasional complaint of tooth mobility. Indeed, resorptivedefects are generally found coincidentally on routine radio-graphic examinations.9 The locations of resorbed teeth indocumented cases have been variable. Such defects havebeen reported to affect the posterior or anterior quadrantsor all teeth.10

Radiographic diagnosis is essential to ensure correcttreatment of the affected tooth. Conventional radiographsare frequently used to detect and follow root resorption.1,4,7-9 However, apical shortening, lateral or cervical root gaps,enlargement of root canals, and external and internal rootradiolucencies are typically not detectable on radiographsat an early stage (when they are small) or because of thelimitations of this twodimensional method.11,12

Cone-beam computed tomography (CBCT) is a relative-ly new three-dimensional (3D) imaging modality requir-ing a significantly lower radiation dose than conventionalcomputed tomography (CT). Endodontic applications ofCBCT include the diagnosis of periapical lesions due topulpal inflammation, the identification and localization ofinternal or external resorption, the detection of verticalroot fractures, the visualization of accessory canals, andassessment of the causes of non-healing endodonticallytreated teeth. The detection and management of internaland external root resorption can be a challenging task andone for which CBCT is well suited.13

The treatment choice should be pulpectomy in the caseof an internal resorption detected radiographically. If theresorption has not led to a large defect in the tooth struc-ture, the resorption can be stopped by an endodontic treat-ment.14

In general, when the cause of external resorption is

known, it can be treated by removing the etiologic fac-tor(s).3 The prognosis is excellent if the condition is man-aged early before any significant loss of tooth structureoccurs; however, if the resorption is dismissed, the prog-nosis is poor. Internal and external resorption representsdifferent pathologic processes that require different treat-ment protocols; therefore, accurate diagnosis is necessaryfor excellent prognosis.15

In this report, we discuss a rare case of multiple idio-pathic external and internal resorption in the permanentmaxillary and mandibular teeth of an otherwise healthy36-year-old male patient evaluated using periapical/pano-ramic radiography and CBCT.

Case Report

A 36-year-old male was referred to our outpatient clinicfor discomfort in the left mandibular second molar undera crown bridge restoration; he experienced slight discom-fort while chewing. There was no history of trauma, hos-pitalization, or medical, endocrine, or systemic disease.Hematological investigations, including a complete bloodcount and measurement of the calcium, phosphorus, andalkaline phosphatase levels, revealed values within thenormal range.

A clinical examination showed no tenderness upon pal-pation of the labial tissues over the periapical region ofany tooth. There was no tenderness to percussion; how-ever, the patient felt discomfort while chewing with theleft mandibular second molar. There was no evidence ofadenopathy, paresthesia, or motor nerve deficiency in thehead and neck area. A clinical examination revealed mod-erate oral hygiene and healthy gingival tissues. The mobil-ity of the teeth was within the normal range. An intraoral

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Multiple idiopathic external and internal resorption: Case report with cone-beam computed tomography findings

Fig. 1. Panoramic image showsmultiple instances of idiopathic in-ternal and external root resorption.

L

examination also revealed that the patient was caries-freeand had four amalgam restorations and a fixed bridge toreplace lost mandibular premolars and molars.

All teeth except the bridge teeth were pulp-tested using arefrigerant spray and electrical pulp test, and all respondedwithin normal limits. Periodontal probing was consistent-ly 3 mm or less, and no bleeding on probing was detected.

Initially, a panoramic radiograph was taken. The radio-graph showed evidence of resorption in several teeth, in-

cluding the right maxillary central incisor, first and secondpremolars, left maxillary central and lateral incisors, sec-ond premolar, and first molar, and the unerupted left max-illary canine (Fig. 1). A decision was made to performCBCT with 3D reconstruction to obtain a more precise lo-cation and definition of the pathological features of the re-sorption sites. CBCT was performed in all three dimen-sions - axial, sagittal, and cross-sectional - with a slice thick-ness of 1 mm by using a Promax CBCT scanner (Planme-

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Fig. 2. A. Axial cone-beam com-puted tomographic images showsites of idiopathic resorption of theteeth. B. Panoramic reconstructedimage clearly demonstrates the res-orptive areas.

A

B

Fig. 3. Cross-sectional cone-beam computed tomographic images show external resorption in molar teeth (arrows).

11 14 15 21 23

ca, Helsinki, Finland) together with 3D rendered images.The axial (Fig. 2A) and panoramic reconstructed images(Fig. 2B) of the left maxillary first molar clearly showedmultiple resorptive areas. The cross-sectional imagesshowed internal resorption of the teeth, including the rightmaxillary central incisor, first and second premolars, leftcentral and lateral incisors, canine, and right mandibularsecond premolar (Fig. 3). Further, external resorption wasfound in the teeth, including the left maxillary second pre-molar, first molar, mandibular second molar, and rightmandibular first molar (Fig. 4). The 3D rendered imageswere not sufficiently clear to detect the nature or extent ofthe external or internal resorption of the teeth (Fig. 5).Based on the diagnosis of multiple internal resorption fromthe panoramic and CBCT images, we decided to performdental examinations of the patients family members toassess multiple resorption because of the possibility of ahereditary influence. However, no clinical or radiographicexamination could be performed because it was not possi-ble to contact any of the family members. CBCT demon-strated that the lesions were generally larger than was evi-

dent from the periapical or panoramic films. No treatmentwas performed because the patient refused treatment.

Discussion

Root resorption of a tooth is a pathological process of in-ternal or external origin. Internal resorption occurs whenthe natural protection of the predentin and odontoblasts inthe root canal is damaged or removed due to the transfor-mation of embryonic connective tissue cells into giant mul-tinucleate odontoclasts. The internal aspect of the root ca-nal is resorbed by activated multinucleate giant cells adja-cent to the granulation tissue in the inflamed pulp. Teethin which the resorptive process reaches the cervical areaof the crown may have a pinkish color, and are known aspink teeth, resulting from granulation tissue ingrow-th.1,16

In contrast, external root resorption in multiple perma-nent teeth is a rare phenomenon. It occurs when the bal-ance between osteoblastic and osteoclastic activities, whichmaintain the physiological state of the tooth root and bone,

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Multiple idiopathic external and internal resorption: Case report with cone-beam computed tomography findings

Fig. 4. Cross-sectional cone-beam computed tomographic images show internal resorption in molar teeth (arrows).

25 26 37 40

Fig. 5. Three-dimensional cone-beam computed tomographic vol-ume rendering images clearly showexternal and internal resorption(arrows).

is disturbed, resulting in the removal of the precementumand cementoblasts from the root surface.10

Resorption of the cementum, dentin, and/or enamel dueto an unknown mechanism not depending on the condi-tions mentioned above, is called idiopathic resorption.Idiopathic resorption in multiple roots is far rarer than re-sorption seen in one or two teeth, and it occurs in a differ-ent pattern from that seen in physiological resorption. Pos-sible causes include microbiologically induced osteoclas-tic or chronic inflammatory activity, familial (genetic)disorders, occlusal trauma, orthodontic tooth movement,systemic disorders, and drug use.8,10 It is thought that theprocess involves the destruction of dentin followed by thecreation of a bony matrix within the resorptive cavity.17

This case had no obvious etiological factor, so there mightbe a genetic component.

Multiple external resorption of permanent teeth is an un-commonly reported phenomenon. Further, certain idiopa-thic cervical root resorption cases have been reported.10,18,19

Soni and La Velle10 and Brooks18 reported that maxillaryteeth were more commonly involved in such cases thanmandibular teeth. Lynch and Ahlberg19 also observed theresorption of the upper first premolars.

Tooth resorption is a problem for dental practitioners,and early detection is important. Conventional radiogra-phic images are frequently used to detect root resorption.However, apical shortening, lateral or cervical root gaps,enlargement of the root canal, and external root radiolu-cencies are typically not detectable on radiographs in theearly stages when they are small or because of the limi-tations of this two-dimensional method. An alternativediagnostic tool for the early detection of root resorption isCBCT. It was used to detect root resorption in the presentcase report. Early detection can lead to timely interven-tion and better treatment outcomes. Root resorption ex-tension is identified by analyzing all lesion dimensions;axial, transverse, and cross-sectional slices can be obtain-ed using CBCT. Root resorption measurements, as part ofa longitudinal follow-up, can determine whether the lesionis in a stage of arrest, repair, or progression. The most im-portant advantage of this imaging modality is acquiringcomparable images with much lower radiation doses thanmultiple-detector CT. In recent studies, it has been con-cluded that the scans produced by CBCT are more accu-rate than periapical radiographs and are an effective andsafe way to detect both horizontal and vertical root frac-tures. It has also been concluded that CBCT should beconsidered when conventional radiographic techniquesfail to provide information for the diagnosis.20-22

Although in the present case the initial diagnosis demon-strates that CBCT was superior in diagnostic efficacy topanoramic imaging with respect to the localization of theextension of the fibrous dysplasia because of the manyaffected bones through the skull, CBCT should not neces-sarily replace panoramic images for following-up the max-illary sinus region after surgery because it involves greaterradiation exposure (4-20 times greater). From the stand-point of radiation risk, CBCT appears to involve 3-7 timesthe dose of a panoramic examination, depending on thearea examined, the degree of collimation, and the acqui-sition software. Thus, the decision to select an imagingmodality for diagnostic purposes should be based on theexpected diagnostic yield and in accordance with the aslow as reasonably achievable principle.20,21

In conclusion, our report presented a case of multipleroot resorption, which was a rare clinical process thatshould be examined using different radiographic modal-ities. Cross-sectional and axial CBCT images would beuseful in the diagnosis and assessment of such lesions.

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