Non-Surgical Management of External Root Resorption of Taurodontic Right Mandibular First Premolar with 2 Roots

‘External Inflammatory Root Resorption’ (EIRR) is a pathological condition affecting the root portion of the tooth that can lead to tooth loss if not diagnosed and treated early and correctly. Calcium Hydroxide [Ca (OH)2] is an excellent intracanal medicament, which is used in cases of teeth with external root resorption and also used in pulp necrosis and peri-radicular lesions. Permanent mandibular first premolar has one single root and rarely found with an additional second root. ‘Taurodontism’ is an embryonic dental anomaly of the tooth relating to tooth morphology characterized by vertically enlarged pulp chambers, apical displacement of pulp floors and short roots. Occurrence of all these rare dental malformations and conditions is a rarity. Therefore, the aim of this clinical case report is to enlighten readers about successful non-surgical management of bifurcated and mesotaurodontic mandibular right first premolar associated with external root resorption.

Keywords: Apical periodontitis, Bifurcated mandibular premolar, Calcium Hydroxide, External root resorption, Taurodontism

Endodontic literature exhibits various types of tooth root resorption such as External Surface Resorption (ESR), External Cervical Resorption (ECR), External Inflammatory Resorption (EIR) and External Replacement Resorption (ERR). External inflammatory resorption or external root resorption (ERR) is the most commonly seen clinical entity characterized by irreversible loss of external tooth structure [1]. Its true etiology is not established but includes multifactorial, but in many aspects remain unclear. Periapical inflammation sustained by infection can cause apical root resorption in permanent teeth [2]. The infection may be asymptomatic for many years, although it is rarely misdiagnosed. Treatment of such lesions should include use of intracanal medicament for complete debridement of the infection. Most commonly calcium hydroxide is used a common endodontic medicament in the treatment of external root resorption [3]. Resorption is also reported involving crown portion of the tooth is of unknown etiology is also reported and, in such instances, it is referred as Idiopathic Intracoronal Crown Resorption (IICR) [4].

Permanent mandibular first molar is an interesting tooth to endodontists, general dentists and pedodontists as it shows numerous variations in its crown morphology as well as in root structure. Variations in root number and canal configuration are encountered during endodontic treatment. Occurrence of two rooted or bifurcated first mandibular premolars is not well studied and hence, literature shows scarcity in prevalence studies [5-7].

Extensive review of dental anomalies occurring in endodontic literature and its management shows challenging task in endodontic management of permanent teeth with taurodontism [7]. Taurodontism is a developmental disturbance of a tooth characterized by characterized by vertically elongated pulp chambers, apical displacement of the pulpal floor and bifurcation or trifurcation of the roots [8-10]. This anomaly is extensively reported involving either permanent or primary molars. Occurrence of generalized type involving all both molars and premolars are rarely seen except in some peculiar syndromes. However, there are paucity of evidence showing its occurrence involving isolated premolars in a non-syndromic patient. Therefore, the aim of this research case report paper is to showcase presence of multiple anomalies with dental pathology like taurodontism, two roots associated with external root resorption in a single tooth (i.e., first premolar) and its successful management using non-surgical method.

A patient of age 28-year-old male patient complains of pain in lower right tooth region from 6 months. There was no history of any systemic diseases or metabolic disorders. On Clinical examination deep caries involving pulp was observed in relation to the mandibular right first premolar. The tooth was tender to percussion. Vitality tests were performed and the tooth was found symptomatic. Based on clinical features a diagnosis of irreversible pulpitis with apical periodontitis with respect to the mandibular right first premolar was made.

Intraoral periapical radiograph using radiovisiography (RVG) was taken with respect to the same tooth which showed extra lingual root (supernumerary root) with presence of extensive root resorption on lingual root of mandibular right first premolar, a large pulp chamber with an elongated body of tooth, shortened roots and furcation located apically (Figure 1-A). Based on radiographic features this case was categorized as mesotaurodont according to Shaw given in 1928 [8]. A treatment plan consisting of arrest of external root resorption and root canal treatment was planned. Conventional Root canal treatment was initiated by giving Ca (OH)2 dressing for 1 month.  In the second appointment, arrest of External root resorption was noticed.  Inferior alveolar nerve block was given to obtain local anesthesia and rubber dam isolation was done. Access cavity was prepared and canals were located. As the premolar had two roots, two canal orifices were found. The pulp chamber was found large because the tooth was mesotaurodontic. Floor of the pulp chamber was not seen. Working length was determined with K-files (Figure 1-B). Biomechanical preparation was done using both hand and rotary instruments. Canals were irrigated with 2.5% sodium hypochlorite solution (NaOCl). Master cone selection was done using gutta percha (ISO standard – 4%) (Figure 1-C). A modified obturation technique was implemented (thermoplasticised obturation technique by using Calamus) consisting of combined lateral condensation of the individual canals followed by vertical compaction of the elongated pulp chamber and Sealapex was used as sealer (Figure 1-D). Access cavity restoration was done using type IX GIC followed by post-endo restoration.

Figure 1: IOPA Radiovisuograph showing mesotaurodontic, two rooted mandibular right first premolar with external root resorption – Red arrow (A), working length determination (B), master cone selection (C) and post-obturation radiograph (D). Complete arrest of external root resorption can be seen (D).

External Root Resorption (ERR) is a pathological root condition occurred secondary to a complication of traumatic dental injury, orthodontic treatment or chronic infection of the pulp or periodontal tissues. The etiological factors are classified as mechanical or chemical factors/stimuli consisting of above-mentioned factors [1,2,10]. Majority time this pathological root condition is detected on routine radiographs. However, sometimes it is identified following evaluation of clinical symptoms like swelling, tooth mobility and pain.  The management of ERR depends on case and its aetiologic factors [2]. The goal of its treatment is to obtain regeneration of the resorptive lesion. Various treatment methods have been explored in its management. However, there are no reports of randomized controlled clinical trials about the efficacy of different interventions for the management of external root resorption. When ERR is associated with intracanal infection and inflammation of the periapical tissues, proper root canal sanitisation is recommended [1,2]. Ca(OH)2 is an excellent endodontic cement extensively researched and has been commonly used as an intracanal medicament in cases of teeth with pulp necrosis, peri-radicular lesions, and severe ERR [1,2]. Its biological and bacteriological properties are associated with the dissociation of calcium and hydroxyl ions [10], which can be influenced by both the vehicle used and additives. A wide range of manufactured Ca(OH)2 products are available in the market for use in Endodontics, including non-setting formulations [7,11-13]. UltraCal XS is a syringe-delivery system consisting of 35% Ca(OH)2 , 19% barium sulphate, 3% propylene glycol, and 2% methylcellulose [12]. The ability of this system to arrest and repair inflammatory ERR has been attributed to its alkalinising effect since the action of inflammatory and clastic cells is enhanced by an acidic pH [11]. The aqueous methylcellulose base of UltraCal XS appears to enhance the diffusion of Ca(OH)2 ions through dentin [11]. This diffusion is also facilitated by the geometry of the smaller particles present in the paste [12]. It is also stated that the Ca(OH)2 particles inside the dentin tubules might act as a direct and continuing source of dissociated Ca(OH)2 , which may result in a high and prolonged local pH [12-14].

An essential knowledge of occurrence of multiple roots and root canals in permanent teeth is essential for success of the root canal treatment. Permanent mandibular first premolars always found with single root and single canal. However, permanent mandibular premolars including both first and second are referred as “Enigma to Endodontist” as they show numerous variations in crown morphology as well as in root number and root canal configuration [15-18]. Failure to identify extra roots and extra canals results in root canal treatment failure. The extra roots are nothing but supernumerary root or additional root. A recent Indian study reported a prevalence of 0.23% of two rooted mandibular first premolars in the population belonging to Indian ethnicity [5]. Another Thai study reported a 28.5% prevalence of two rooted mandibular premolars in Thai population investigated using Cone Beam Computed Tomographic images [6]. There are reports showing two rooted mandibular second premolars [7]. In the present case, mandibular first premolar had two roots and two canals.

Taurodontism is a developmental dental anomaly of the tooth pertaining to morphology characterized by vertically enlarged pulp chambers, apical displacement of pulp floors and short roots [8,10].  This rare embryologic anomaly of the teeth has been classified as cyno, hypo, meso or hypertaurodontism according to the severity of the anomaly. Taurodontism is found with a prevalence of 0.25% to 11.3% in general population. In the present case, first premolar exhibited a mesotaurdontism. Although Taurodontism is a dental rarity and a challenge to the dentist, thorough knowledge of dental anatomy and its radiographic examination should be well-understood by clinicians. [8,10].

In the present case, the permanent mandibular first premolar exhibited mesotaurodontism hence, a modified obturation technique was followed as suggested by various clinicians which includes combined lateral condensation of the individual canals followed by vertical compaction of the elongated pulp chamber using thermoplasticised obturation technique. Because of the complexity of irregular root canal configuration in taurodontic teeth, sufficient instrumentation is also not obtained [10]. Therefore, literature suggests use of 2.5% sodium hypochlorite which improves root canal cleaning as well as dissolves the remaining pulp stones. The same irrigation solution was used in the case described here.

Therefore, pre-operative diagnosis of the tooth is highly important to detect presence of unusual root and canal variations like multiple roots, internal or external root resorption, vertucci’s canal configuration and taurodontism prior to root canal treatment. [6-18]. The present case is the illustration for showing the successful management of external root resorption caused by pulp inflammation in a permanent mandibular first premolar associated with two roots and mesotaurodontism. The external root resorption was successfully treated in non-surgical method using calcium hydroxide material. In the second visit follow-up, external root resorption was completely halted and hence the root canals were obturated using modified obturation technique using thermoplasticized gutta percha.

A thorough knowledge on presence of unusual root variations involving morphology like taurodontism and root number like bifurcated roots in a tooth is very important among all dental professionals. This is because the management of such teeth entirely differs from normal teeth and if not detected will result in treatment failure.