Indian Journal of Dental Research

: 2013  |  Volume : 24  |  Issue : 1  |  Page : 123--127

Endodontic retreatment - unusual anatomy of a maxillary second and mandibular first premolar: Report of two cases

Amarnath Shenoy1, Nagesh Bolla2, Sayesh Vemuri2, Jacob Kurian2,  
1 Department of Conservative Dentistry, Yenepoya Dental College, Deralakatte, Mangalore, India
2 Department of Conservative Dentistry, SIBAR Dental College, Guntur, Andhra Pradesh, India

Correspondence Address:
Amarnath Shenoy
Department of Conservative Dentistry, Yenepoya Dental College, Deralakatte, Mangalore


An accurate diagnosis of the morphology of the root canal system is a prerequisite for successful root canal treatment. A major cause of endodontic treatment failure in missed (or) untreated root canals is that they still harbor infection. Careful radiographic interpretation and examination of pulp chamber floors are helpful in locating root canal entrances. These case reports present anatomical variations in upper and lower premolars.

How to cite this article:
Shenoy A, Bolla N, Vemuri S, Kurian J. Endodontic retreatment - unusual anatomy of a maxillary second and mandibular first premolar: Report of two cases.Indian J Dent Res 2013;24:123-127

How to cite this URL:
Shenoy A, Bolla N, Vemuri S, Kurian J. Endodontic retreatment - unusual anatomy of a maxillary second and mandibular first premolar: Report of two cases. Indian J Dent Res [serial online] 2013 [cited 2021 Aug 1 ];24:123-127
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A detailed knowledge of morphology of root canal system and thorough cleaning and shaping of root canals are required for successful management of infection in root canal system. [1],[2] Studies on maxillary premolars show a low incidence of three root canals. [3] Maxillary second premolars usually have one root with one or two root canals. Vertucci reported the occurrence of one canal at the apex in them at 75% and two canals at the apex at 24%. In the same study, Vertucci found maxillary second premolars with three canals at the apex to be only 1%. [4] Maxillary premolars with three root canals were sometimes called small molars or "ridiculous" because of their similar anatomy to that of adjacent maxillary molars. [5]

Normally mandibular first and second premolar teeth have single roots with single canals. Sherman and Hasselgren reported a high incidence (18.1%) of multiple roots and canals in mandibular premolar teeth in a series of radiographic surveys with mandibular first premolars involved in 15.7% of patients and mandibular second premolars in 7% of the patients. [6]

The root canals which are left untreated because of morphological variations are the source of infection. These case reports describe the successful diagnosis and the treatment of missed canals.

 Case Reports

Case report:1

Maxillary second premolar with three roots

A 28-year-old male patient reported to the Department of Conservative Dentistry and Endodontics with the chief complaint of pain in upper left back tooth region with a previous history of root canal therapy done few months back in a private clinic. The tooth was symptomatic and tender on percussion. There was no swelling or fistula present, and the case was referred to the Post Graduate clinic. No relevant medical history was noted. The pre-operative radiograph was examined thoroughly, mesio-distal width of mid root was equal to that of crown and double periodontal ligament space was found (# 25), which gave evidence of the presence of another root mesially [Figure 1]. The patient was informed about the future treatment modality and consent for the same was obtained. The patient was administered with 2% Lignocaine HCL in 1:80,000 s Adrenaline, the tooth was isolated with rubber dam and the post endodontic restorative material was removed with high speed airotor. The two obturated root canal entrances were found, access cavity was extended mesiobuccally, a third canal was explored carefully with DG 16 explorer in the mesiobuccal region. The endodontic map was similar to a maxillary first molar with a palatal, mesiobuccal, and distobuccal canals. The gutta-percha was removed from the previously filled canals with the aid of H files and Gates Glidden drills and working length was determined [Figure 2].{Figure 1}{Figure 2}

Along with the cleaning and shaping of missed canal, the other two canals were also thoroughly instrumented, and cleaning and shaping done by step down preparation upto size F2 Protaper (DENTSPLY). The root canals were irrigated using 3% sodium hypochlorite and MTAD solutions during root canal treatment. The canals were then dried with sterilized paper points, dressed with calcium hydroxide paste, and the access cavity was sealed with cavit (3 M ESPE, Germany). At the second appointment the root canals were obturated with F2 gutta percha points using AH plus sealer [Figure 3]. Access cavity was restored with bonded amalgam. Final radiograph was then taken to confirm the quality of obturation. Patient was recalled after a week for evaluation and the tooth was found to be asymptomatic. Full coverage post-endodontic restoration was given. At 6 months review there was no radiographic evidence of apical periodontitis [Figure 4].{Figure 3}{Figure 4}

Case report:2

Mandibular premolar with two root canals

A 34-year-old female patient came to the Department of Endodontics with the chief complaint of pain and mild intraoral swelling in mandibular right first premolar region (# 44) which was root canal treated 1 week back. Post-operative radiograph was normal (# 44) [Figure 5]. On clinical examination, the mandibular first premolar was tender to percussion. A radiograph was taken with cone shift technique; there was a bifurcation in the middle third of the root which hinted the presence of untreated canal [Figure 6]. It was found to be Type V root canal configuration according to Vertucci. The patient was informed about the future treatment modality and consent for the same was obtained. The patient was administered with 2% Lignocaine; the tooth was isolated with rubber dam and the post-endodontic temporary restorative material was removed. Gutta percha was removed from the previously filled canal upto the bifurcation area. Coronal and middle third were enlarged with Gates Glidden drills. The bifurcated canal was explored carefully lingual to the filled canal and working length was determined [Figure 7]. The cleaning and shaping, irrigation and the intracanal dressing regimen were followed as in the above said case report 1. At the second appointment the canal was irrigated with saline and obturated with Protaper gutta-percha [Figure 8]. Gutta percha was removed till bifurcation and the remaining canal was filled with thermo-plasticized gutta percha (Obtura). Patient was recalled after 1 week and the symptoms were found to be subsided and full coverage post-endodontic restoration was given. Six months later post-operative radiograph was taken and no pathology was detected [Figure 9].{Figure 5}{Figure 6}{Figure 7}{Figure 8}{Figure 9}


The possible anatomic configurations of maxillary and mandibular premolars are well documented in the literature. High quality pre-operative radiographs and careful examination are essential for the detection of additional root canals. [7] Many of the difficulties found in the root canal treatment are due to variations in root canal morphology. But, the literature shows only a few cases related to three rooted maxillary second premolar, [8],[9] and two rooted mandibular first premolar. [10]

Visualization of three-canalled maxillary premolars on preoperative radiographs can often be difficult. In straight-on radiographs of maxillary premolars, Sieraski et al. found that whenever the mesio-distal width of the mid root image was equal to or greater than the mesio-distal width of the crown; the tooth most likely had three roots. [11] In the treatment of three rooted maxillary first premolars, Balleri et al. suggested a T-shaped access outline which is helpful for locating all the canals. Based on this and double periodontal ligament space observed in the radiograph we proceeded for the treatment.

Vertucci described five different types of canal configuration for mandibular first premolar. Muller reported that root canals in the mandibular first premolars were usually round and conical, but inclined to be ribbon like in the cervical third of the root. He also reported that if the canal is very wide bucco-lingually, it can suddenly narrow into bifurcation; making two very small canals. [2] In this case the root canal system was characterized by a complete mid root separation of the canals into buccal and lingual root canal system.

When anatomic variations are detected clinically conventional or rotary treatment can be done respecting technical and biological principles. Apex locators can be used for working length determination. The deformation of stainless steel instruments can give additional information about anatomic variations. [12]

Accurate pre-operative radiographs are very important. Straight and angled radiographs and the use of parallel technique are very essential in providing clues for the number of roots that exist. Morphologic variations in pulpal anatomy must be always considered before beginning treatment. [13]

The use of magnification and additional lighting are recommended for the clinical examination of the pulpal floor. [14]

Slowey suggests mandibular premolar to be the teeth which is the most difficult on which endodontic treatment can be successfully performed. [15]

In one study mandibular first premolar showed the highest failure rate. Numerous endodontic failures and flare ups have also been reported during the course of non-surgical root canal therapy. [15],[16],[17]

Possible reasons for this conclusion are the numerous variations in root canal morphology and difficult access to the canal systems when present. Numerous factors contribute to variations found in the root and root canal studies reported. [18] These factors include ethnicity, [19],[15] age, [15] sex, [15] and unintentional bias in selection of clinical examples of teeth (specialty endodontic practice versus general dental practice) [18] and study design (in vitro versus in vivo).

Utilizing the advanced technology like microscopes and computerized tomography makes easier for clinician to treat and identify missed canals. The complex nature of the root canal and its morphology has been underestimated in the past. Review of literatures reveals a complex root morphology as well as complex internal canal morphology. This finding deserves more emphasis in textbooks on the subject of endodontics and confirms an early paper on the complexity of root canal anatomy by Slowey. [15]

Since 1980s cone beam technology has existed, but its application in dentistry is done recently. CBVT ensures elimination of superimposition of anatomic structures, an undistorted three dimensional of maxillofacial skeleton and a lower effective radiation dose compared with conventional computed tomography (CT). CBVT provides viewing of an image in multiple planes. [20]


Knowledge of dental anatomy is fundamental for good endodontic practice. Though variations in root canal configurations do not come across regularly, an adept clinician should very carefully investigate each case clinically and radiographically, to avoid post endodontic flare-ups. There should be constant vigilance in locating two or more canal systems when performing root canal therapy in premolars.If not the additional canals may be missed, resulting in greater failure rate.


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