Multiple idiopathic cervical root resorption: Diagnosis, clinical/radiographical/histological presentation, and rehabilitation - A 7-year follow-up case report.

Multiple idiopathic cervical root resorption (MICRR) is a rare condition. The etiology is unknown and occurs spontaneously in healthy controls in the absence of local, systemic, or any other plausible cause. The teeth themselves appear clinically normal. The pattern of resorption begins in cementoenamel junction and can progress rapidly over a short time. It is a debilitating condition which often leads to extraction of all the involved teeth. This article describes a case of MICRR over a period of 7 years with emphasis on the history, clinical/histological findings, cone beam computed tomographic examination, therapeutic intervention as well as the final prosthodontic rehabilitation with implants.

INTRODUCTION

Root resorption in deciduous teeth is a physiological process. However, when observed in permanent teeth, it is an unfortunate and unpredictable phenomenon. The etiology of one root resorption known as “idiopathic root resorption” remains mysterious. It occurs spontaneously in healthy controls in the absence of local, systemic, or any other plausible cause.

Muller and Rony[1] in 1930 reported a case of multiple idiopathic cervical root resorption (MICRR), and since that time, only few cases have been documented. Idiopathic root resorption affects either or both apical and cervical regions of one or several teeth, but most commonly occurs in the apical region. It may be confined to one arch or distributed throughout the entire dentition. A predilection for young females has been documented. The number of involved teeth ranges from three to more than 20 per individual. Management poses serious problems, and the condition is generally progressive and leads to loss of affected teeth.[2]

In this article, a case of MICRR is documented over a period of 7 years with emphasis on the history, clinical/histological findings, cone beam computed tomographic (CBCT) examination, therapeutic intervention as well as the final prosthodontic rehabilitation.

CASE REPORT

A 23-year-old Indian female reported to the Division of Conservative Dentistry and Endodontics in 2011 with the complaint of dull continuous pain and mobility of her lower front teeth for the last 4 months. Past dental history revealed endodontic intervention and surgical curettage in relation to teeth #41, 42, and 43. A thorough clinical examination revealed overall good oral hygiene with healthy gingival tissues except in relation to teeth #41, #42, and #43 which showed signs of postoperative edema [Figure 1a–d]. The patient was caries free and never had a restoration. Pulp sensibility testing with refrigerant spray and electric test revealed normal response from all the teeth except the endodontically treated ones. Teeth were not tender to percussion and gave a normal sound on percussion. Mobility was normal for all teeth except teeth #41–43 which showed moderate mobility. Periodontal probing was consistently 3.5 mm or less, and mild bleeding on probing was detected.

Figure 1

(a-d) Preoperative intraoral clinic picture, (e) preoperative orthopantomogram, (f-h) preoperative intraoral periapical X-rays, (i-k) cone beam computed tomographic scans

The patient had a previous orthopantomogram (OPG) which showed multiple cervical radiolucent defects. Full-mouth periapical radiograph was taken which showed cervical resorptive defects involving ten teeth. The severity of resorption varied among teeth, from a small distal lesion on teeth #31, #46 and moderate resorption on teeth #45, #25 to severe resorption involving more than half of the total tooth length on remaining six teeth with apparent pulpal involvement [Figure 1e–h].

CBCT imaging (i-CAT Model-Next Generation, Imaging Science International, Hatfield, PA, USA) demonstrated resorptive defects in 15 teeth. The lesions were generally larger than was evident from periapical films or OPGs. Buccal and lingual/palatal lesions were readily visible on CBCT images, and extension into the pulp chamber in nine teeth could also be seen (although without any clinical evidence of pulpal pathology). Lesions extended coronally beneath enamel, which appeared to remain intact even when it was extensively undermined [Figure 1i–k].

Her medical and family histories were noncontributory. She was referred to an endocrinologist who took out blood investigation to rule out any systemic cause which revealed normal calcium, phosphate, alkaline phosphatase, T3/T4, thyroid-stimulating hormone, and parathyroid hormone level. Whole-body bone scan (Tc-methylene diphosphonate) was also carried out which revealed normal radioisotope uptake by the bone. She had neither sustained any trauma nor undergone orthodontic treatment/bleaching.

Written consent form was taken. After giving adequate local anesthesia (Xylocaine, lidocaine HCl Injection, USP), teeth #41 to #44 were extracted surgically. Granulation tissue over the small cervical defects present on teeth #45 and #31 was removed. The defects were cleaned using ultrasonic tips (Spartan, Fenton, MI), irrigated copiously with 2.5% sodium hypochlorite, and dried. Mineral trioxide aggregate (ProRoot™ MTA, Dentsply Tulsa Dental, Tulsa, OK) was mixed in a 3:1 proportion and condensed into the resorptive areas. A moist cotton was used to flush the margins. A collagen barrier (Metrogene, Septodont, France) was placed over the sealed defects [Figure 2a–d]. This was followed by suturing of the surgical area. An immediate removable partial denture was prepared from preoperative alginate impression taken and was fitted on the edentulous space left after extraction. The extracted tooth and a portion of the alveolar bone were fixed in 4% paraformaldehyde, decalcified, and subjected to routine histological procedures. Sections were stained with hematoxylin and eosin. Histopathology revealed the presence of multinucleated odontoclasts residing in resorption bays near dentin. Irregular immature bony trabeculae and giant cells in fibrous stroma were also found [Figure 2e and f]. The remaining defects were sealed in the similar manner in the following appointments. The patient was asked to be under regular follow-up.

Figure 2

(a, b and d) Restoration of cervical defects with mineral trioxide aggregate, (c) cervical defect after curettage, (e) histopathological evaluation showing odontoclasts residing in resorption bays near dentin, (f) histopathological evaluation showing irregular immature bony trabeculae and giant cells in fibrous stroma, (g) implant placement, (h) implant-retained prosthesis, (i) 7-year follow-up orthopantomogram showing new resorptive lesions

However, after a follow-up period of 2 years, it was found that resorption continued in the MTA-treated teeth. Few more teeth (maxillary and remaining mandibular anterior) were found to be involved with the resorptive process. Hence, a treatment plan was decided to extract the involved teeth followed by prosthodontic rehabilitation.

PROSTHODONTIC REHABILITATION

All the treatment options were explained to the patient, and a treatment plan was made keeping in view the patient need and demands. Main treatment options in this case were immediate partial denture followed by cast partial denture, fixed dental prosthesis, implant-retained prosthesis, or implant-supported removable prosthesis.

The option of cast partial denture or fixed dental prosthesis was excluded since the remaining teeth also had sign of external root resorption but did not require extraction at this stage. Therefore, an implant-retained/implant-supported prosthesis was planned since the patient was willing for fixed prosthesis only.

CBCT images of edentulous area were taken to evaluate the bone quality as well as quantity. CBCT images showed very less (1.5–1.8 mm) bone width in mandibular anterior region. Four delayed implants in the region of #34, #43, #44, and #46 with ridge expansion using platelet-rich fibrin (PRF) as graft material was planned, and five immediate implants in relation to #13, #14, #23, #24, and #35 using PRF as graft material were planned with delayed loading. All the implants were left in situ for 6 months for complete osteointegration [Figure 2g]. After six months, stage two surgery was performed and subsequently cement-retained fixed prosthesis (PFM) with implant-protected occlusion was fabricated [Figure 2h]. The patient was explained to maintain the cleanliness of the implants as well as fixed prosthesis. She was kept on a regular follow-up. Follow-up OPG at 7 years revealed normal implant function and commencement of new resorptive lesions in multiple teeth which will be managed accordingly [Figure 2i].

DISCUSSION

Multiple external resorption of permanent teeth is an uncommonly reported phenomenon. External resorption of primary and permanent teeth has been reported to occur secondary to trauma, infection, periodontal disease, endodontic treatment, encroachment from neoplasm, orthodontic treatment, and bleaching.[3] Systemic conditions associated with resorption have been hemifacial atrophy (Perry–Romberg syndrome), osteogenesis imperfecta, Paget's disease, hyperparathyroidism, Papillon–Lefevre syndrome, hypophosphatemia, Stevens–Johnson syndrome, hormonal disturbance, renal disease, hepatic disease, and bone dysplasia. Abnormal root resorption of the entire primary and permanent dentition has also occurred or may be interpreted as occurring in dentinogenesis imperfecta, amelogenesis imperfecta, dentinal dysplasia, and odontodysplasia.[4] External root resorption which develops in the absence of a plausible cause is termed idiopathic. Idiopathic root resorption is thus a diagnosis of exclusion.[5] Hence, this case was also diagnosed as external cervical idiopathic root resorption because of absence of any local, systemic, or iatrogenic factors as well as lack of any suggestive history.

The common features seen in literature so far are normal clinical appearance of teeth and supporting structures, predilection in young females, resorption associated with vital teeth as well as endodontically treated teeth, defect not involving pulp space, absence of local etiological factors, lack of periodontal/periradicular inflammation, normal alveolar bone level, ingrowth of alveolar bone into defects, and asymptomatic patient until later stages where increased tooth mobility is reported.[3] This case differed from previously reported cases in having mild bone loss, no bone ingrowth, and pulp space involvement without any signs of pulpal pathosis. Since the lesion has been described as progressive, there is no question of not involving the pulp space in advanced stages.

Routine use of CBCT has been recommended in evaluating cases on MICRR since it is useful in demonstrating the extent of the lesions more precisely, especially on buccal and lingual/palatal surfaces.[6]

Histological findings of this case were inconclusive as it revealed immature bony trabeculae with giant cells in stroma mimicking that of fibrous dysplasia. However, it was unsupported by the clinical, radiographical, and laboratory examination.

Treatment planning for generalized, progressive resorption has been a challenge. Due to lack of any treatment protocol, it is often ad hoc based. The range of options undertaken in individual cases includes (i) observation, with episodic extraction and prosthetic replacement of fractured teeth; (ii) early intervention with surgical exposure, curettage of lesions, and restoration with glass ionomer cement (sometimes with root canal treatment of involved teeth); (iii) crown resection with root submergence to preserve alveolar bone and prosthetic replacement; (iv) extraction and replacement with implants; (v) extraction of all teeth, with full dentures; and (vi) medical management using bisphosphonates to arrest resorption.[6]

Surgical intervention to expose early lesions with curettage followed by restoration with amalgam, glass ionomer cement, or resin composite has been reported in several cases.[78910] Our study is the first of its kind to use MTA in MICRR. MTA has been shown to prevent/arrest resorption by the following process: increasing the surface pH and thus inhibiting osteoclastic acid phosphatase, release of calcium ions leading to repair of resorptive defects by reparative cementum deposition, and finally by maintaining the OPG expression in osteoblasts which is a key negative regulator of osteoclastogenesis.[11] However, MTA failed to arrest the resorption in this case. The reason for recurrence is probably their aggressive nature. Small infiltrative channels are created within the dentine, and these may be interconnected with the periodontal ligament; unless all osteoclasts in these infiltrative channels are removed, the resorptive process will continue.[12] Extraction and subsequent replacement of the tooth was found to be the eventual solution.

Clinical treatments with dental implants for replacement of teeth damaged due to root resorption have been documented to have good outcomes.[13] The advantages of such treatment include enhanced esthetics, improved function, and bone preservation.

CONCLUSION

Diseases can produce perplexing clinical presentation for even an astute clinician. Thorough knowledge and clinical skills are required for proper diagnosis and management. Idiopathic external root resorption is an enigma which remains to be deciphered.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.