external root resorption ( err ) is a pathologic condition caused by several etiological factors , this inflammatory response can exacerbate in the presence of bacteria and their by - products inside the root canal system and dentinal tubules after pulp necrosis and in the absence of protection of cementum barriers . if allowed to progress , the resorption process may lead to rapid tooth loss . the major challenges associated with endodontic treatment of teeth with open apices due to resorption are achieving complete debridement , canal disinfection , and optimal sealing . one of the aims of endodontic treatment is to form an apical barrier or a stop against which one can place canal filling material avoiding over extrusion . recently mineral trioxide aggregate ( mta ) has emerged as a reliable material due to its biocompatibility , good sealing property , and it encourages regeneration of peri - radicular tissues such as periodontal ligament bone and cementum . these favorable properties render mta a suitable material for the management of tissues damage caused by err . the orthograde filling of the entire root canal system with mta is the logical progression in the evolutionary application of this material . the present case report describes the advanced err in the mandibular molar , which is treated with mta obturation . a 22-year - old male patient reported to the department of endodontic , with the chief complaint of pain with the lower right back region of tooth . he gave history of discontinued root canal treatment with same tooth [ figure 1 ] . there was no relevant medical history . on clinical examination of tooth # 46 , tooth was temporarily restored , tender to vertical percussion and there was no mobility seen . intraoral periapical radiographic examination of tooth # 46 revealed extensive apical root resorption on both the roots , associated with diffused periapical radiolucency some bone loss . taking into consideration the extent and the severity of the resorption , it was planned for orthograde mta obturation of the canal space to arrest the resorption . the existing access cavity was modified and working length of the tooth was determined with help of apex locator , propex - ii ( dentsply ) . canals were cleaned and shaped with the help protaper rotary ( dentsply , tulsa dental specialities , ballaigues , switzerland ) up to f2 , irrigating with copious amount of 3% of sodium hypochlorite , ( vishal dentocare pvt . ltd . this was followed by irrigation with normal saline to remove any remnants of hypochlorite , latter canals were dried with absorbents points and calcium hydroxide ( r c cal , prime dental products , kalher , thane ) as an intracanal medicament was placed in canals followed by a temporary restorations for 1 week . mta , pro - root mta ( dentsply , tulsa switzerland ) was manipulated according to manufacture instructions . both the distal and mesial canals were obturated with mta , material was placed in the canals with amalgam carrier and was condensed vertically with hand pluggers . after completion of obturation orifices were sealed , followed by postendodontic restoration [ figure 2 ] . the patient was recalled after 6 [ figure 3 ] and 24 [ figure 4 ] months for clinical and radiograph follow up . intraoral periapical radiograph showed regression in the size of periapical radiolucency with sign of osseous repair and no further progression of err [ figure 4 ] . err is one of the most difficult dental conditions to treat ; attempting to perform endodontic therapy for every condition of external resorption is futile . when the pathway of communication is opened between the root canal and the periodontium it must be sealed with materials that preserves bacterial leakage , this material should be biocompatible and should favor regeneration of supporting structure . three dimensional sealing of the root canal is one of the principle goals of endodontic treatment and is essential for preventing apical and coronal leakage in the root canal system . a current trend in endodontic research is to explore various alternatives to gutta - percha to identify suitable filling materials that can provide greater resistance against coronal and apical leakage and thus protection from bacterial contamination . development of new bioactive material such as mta makes possible other therapeutic approaches including the obturation of root canal space in complex cases of pathologic root resorption . one of the characteristics of bioactive material is its ability to form an apatite like layer on its surface when it comes in contact with physiologic fluids in vivo or with stimulated body fluid in vitro , is mta a bioactive material that is mainly composed of tricalcium and silicate . investigation has shown that it can conduct and induct hard tissue formation ; studies have illustrated the release of various ions from mta . observed an initial ph of 10.2 for mta rising to 12.5 in 3 hours , it is known that ph level in order of 12.0 can inhibit most microorganisms including resistant bacteria such as enterococcus faecalis . in addition to its well documented biocompatibility the production of bone morphogenic protein-2 and transferring growth factor beta-1 could be two important contributors to the favorable biologic response stimulated mta in periapical tissues . it is also shown that the stimulation of interleukin production by mta may influence the over growth of cementum and facilitates the regeneration of periodontal ligament and formation of bone . recent studies have reported on the success of mta - root end apical barrier ranging from 76.5% to 91% . in this study , mta was the choice of material to obturate the canals . patient was evaluated after 24 months , tooth was asymptomatic , and radiograph showed successful healing with apical closure of both the mesial and distal roots . mta is proved to be the material as it leads to avoidance of surgical treatment with similar prognostic outcome .
external root resorption ( err ) is a lytic process occurring in the cementum or cementum and dentin of the roots of teeth . here 
 we report a case of inflammatory err in a mandibular right molar in a 22-year - old male patient with history of incomplete root canal treatment with the same . considering the biological properties of mineral trioxide aggregate cement , especially its alkalinity and sustained calcium hydroxide release , 
 this material was used for the treatment of err , followed by permanent prosthesis . 
 the clinical and radiographic follow - up for 24 months revealed that treated teeth were functional , the progression of the err had ceased , the resorptive area were replaced with newly formed bone and periapical radiolucencies was healed .