"Internal root resorption: An endodontic challenge": A case series.

Management of internal root resorption is a challenge to the endodontists. It may occur in cases with chronic pulpal inflammation, following caries or due to trauma in the form of an accidental blow. Most cases of internal root resorption are seen in anterior teeth, due to their susceptibility to trauma. However, it may be seen in posterior teeth, most likely because of carious involvement of the pulp. Early diagnosis, removal of the cause, proper treatment of the resorbed root is mandatory for successful treatment outcome. This paper is an attempt to summarize the knowledge on internal root resorption and present various cases, which were successfully managed with different treatment modalities.

INTRODUCTION

Resorption is defined as a condition associated with either a physiologic or a pathologic process resulting in loss of dentin, cementum or bone.[1] Andreasen has classified tooth resorption as Internal (Inflammatory, Replacement) and External (Surface, Inflammatory and Replacement).[2]

Internal root resorption is the progressive destruction of intraradicular dentin and dentinal tubules along the middle and apical thirds of the canal walls as a result of clastic activities.[3] It is seen as a radiolucent area around the pulpal cavity, usually of incisors and mandibular molars. The various etiological factors suggested for internal root resorption include traumatic injury; infection and orthodontic treatment.[4]

Resorption occurs in two stages: Degradation of the inorganic mineral structure followed by disintegration of the organic matrix.[5] Internal inflammatory resorption involves progressive loss of dentin, whereas root canal replacement resorption involves subsequent deposition of hard tissue that resembles bone or cementum but not dentin.[6] Internal inflammatory resorption can be perforating or non-perforating root resorption.

Clinically, the condition is usually asymptomatic, however, it may include the presence of a reddish area – pink spot, which represents the granulation tissue showing through the resorbed area. Radiographs are mandatory for diagnosing internal resorption, which reveals a round-to-oval radiolucent enlargement of the pulp space.[24] The margins are smooth and clearly defined with distortion of the original root canal outline.

Internal resorption can be detected by: Visual examination based on changed color in tooth crown, radiographic diagnosis, conventional and cone beam computed tomography, light microscopy and electron microscopy.[78]

Various materials available for the treatment of internal root resorption include MTA, glass ionomer cement, Super EBA, hydrophilic plastic polymer (2-hydroxyethyl methacrylate with barium salts), zinc oxide eugenol and zinc acetate cement, amalgam alloy, composite resin and thermoplasticized gutta-percha administered either by injection or condensation techniques.

Perforating internal resorption may complicate the prognosis of endodontic treatment due to weakening of the remaining dental structure and possible periodontal involvement. However, prognosis of the tooth can be influenced by the biomaterial employed for the treatment. MTA is most commonly used because of its biocompatibility, sealing ability and potential induction of osteogenesis and cementogenesis followed by thermoplasticized gutta-percha obturation techniques.[910]

This paper insights case series involving non-perforating and perforating internal resorption cases, which were successfully managed and showed successful healing after 8 months to 1 year follow-up period.

CASE REPORT

Non perforating internal inflammatory resorption

A 45-year-old female patient came to the department with a chief complaint of dull pain in upper right front tooth region since one month. Her medical history showed that she had Stevens Johnsons Syndrome since the past five years and was under medication for the same.

The clinical examination showed distal caries wrt 12. Caries was also present wrt 13. Radiographic examination showed radiolucency in middle third of root surface of the lateral incisor indicating a case of internal resorption and an associated radiolucency in the periapical area of same tooth [Figure 1a]. Also there was widening of periodontal ligament wrt 13. The diagnosis of necrotic pulp with chronic periapical abscess wrt 12 and asymptomtic apical periodontitis wrt 13 was made. It was decided to complete the endodontic therapy for the tooth 12 first.

Figure 1

(a) Preoperative radiograph (b) Postobturation radiograph (c) 1 year follow up radiograph

Access opening was initiated without local anaesthesia since the tooth was non-vital. Working length radiograph was taken wrt 12. Biomechanical preparation of the tooth was done in the first visit. In the next visit, 2 days later the tooth was prepared till 50 no. K file.

Master cone was then selected corresponding to the required biomechanical preparation. Thick consistency of the sealer (Endomethasone) was mixed and properly applied with lentulospiral into the canal and the resorptive defect followed by obturation of the canal using warm vertical condensation method [Figure 1b].

The patient was recalled on a regular basis for upto one year [Figure 1c]. Meanwhile the adjacent tooth was also treated. The follow-up radiograph after one year showed peri-apical healing of the lateral incisor.

Perforating internal inflammatory resorption

A 38-year-old male reported to the Department of Conservative Dentistry and Endodontics with complaint of grossly decayed teeth in the mandibular right second molar region since one year. Medical history of the patient was non-contributory.

Clinically there was grossly destructed mandibular second molar. Periapical radiograph revealed a radiolucent lesion in the apical third of the distal root continuous with the distal radicular surface, suggestive of a perforating resorptive defect [Figure 2a]. An oval shaped radiolucency was also seen in the coronal third of the distal root canal. The diagnosis was inflammatory perforating internal resorption.

Figure 2

(a) Preoperative radiograph (b) 2B-MTA plug (c) Postoperative radiograph (d) 8 months follow up radiograph

After rubber dam application, access opening was made. Working length was determined radiographically and recorded. Biomechanical preparation was done in the mesial root using M two-rotary system #25 while the distal canal was prepared with hand K files till 50.

The resorptive defect in the distal canal was the repaired with MTA plug in the apical 3 mm of the canal [Figure 2b]. After the setting of the MTA plug the tooth was obturated using Obtura II thermoplasticized gutta-percha [Figure 2c]. After post obturation restoration crown cutting was done and PFM crown was placed. An eight month follow-up radiograph showed uneventful healing of the lesion [Figure 2d].

Retreatment of perforating internal inflammatory resorption

A 25-year-old male reported to the Department of Conservative Dentistry and Endodontics with complaint of pain in the mandibular left second molar region since 15 days. Patient got endodontic treatment of the same tooth two years back. Medical history of the patient was non-contributory.

Clinical examination revealed grossly destructed mandibular left second molar. Radiographic examination showed inadequate obturation and persistent apical periodontitis with perforating internal root resorption with respect to tooth 37 [Figure 3a].

Figure 3

(a) Preoperative radiograph (b) Postoperative radiograph (c) 1 year follow up radiograph

After rubber dam application access opening was modified. Gutta-percha was removed and working length was determined radiographically and recorded. Calcium Hydroxide dressing was given and patient was recalled after 21 days. Coronal flaring was done using gates glidden drill no 2 and 3. Biomechanical preparation was done using hand K files. Distal canal was prepared till # 50 and mesiobuccal and mesiolingual canals were prepared till #25.

The resorptive defect in the distal canal was the repaired with MTA plug in the apical 3 mm of the canal. After the setting of the MTA plug the canal was obturated with thermoplasticized gutta-percha. The mesial root canals were obturated with gutta-percha and endomethasone sealer using lateral condensation technique [Figure 3b]. Post-obturation restoration was done. A one year follow-up radiograph showed successful healing of the lesion [Figure 3c].

DISCUSSION

There is always a dilemma of whether to treat a tooth with a questionable prognosis endodontically or extract it and subsequently place an implant. Bell first reported a case on internal resorption in 1830. Since then there have been numerous reports in the literature.[11] It is a multifactorial process associated with various factors, which may be categorized in to physiological resorption, local factors, systemic condition and idiopathic resorption.

Internal resorption is the result of an inflamed pulp and the clastic precursor cells recruiting through the blood vessels. Treatment of internal resorption is quite predictable as it is easy to control the process of internal root resorption via severing the blood supply to the resorbing tissues with conventional root canal therapy. In teeth with perforating defects, remineralization of the defect may occur, formation of hard tissue matrix against which permanent root canal filling is condensed or surgical approach and some cases may require extraction.[3] In the present case series, different examples with available treatment approaches are included.

In the case report 1, The systemic condition of the patient (Steven Johnson Syndrome) could be the reason for the internal resorption. The defect was non-perforating which was filled with warm vertical condensation after cleaning and shaping of the canals.

In case report 2 and 3, extensive resorptive defect was seen in the distal canal. MTA was used to make the apical plug of 3 mm because of its biocompatibility, sealing ability and potential induction of osteogenesis and cementogenesis. It was followed by thermoplasticized gutta-percha obturation to form a three-dimensional seal.

Hence, all the perforating resorptive defects were treated by sealing the perforation by MTA and then filling the canal with thermoplasticized gutta-percha. In non-perforating internal resorption, the defect was filled with warm vertical condensation technique.

CONCLUSION

Early diagnosis, removal of the cause, proper treatment of the resorbed root is mandatory for successful treatment outcome. Internal resorption is an uncommon resorption of the tooth, which starts from the root canal and destroys the surrounding tooth structure. It is easy to control the process of internal root resorption via severing the blood supply to the resorbing tissues with conventional root canal therapy. Regular recall is important to check the status of healing and for the overall prognosis of the tooth.