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KeyWords: Working length, maxillary canine, root canal treatment, success


A successful root canal therapy requires complete removal of the pulp followed by thorough cleaning, shaping and obturation of the root canal system so that the tooth may maintain its integrity as a functional unit within the dental arch. For endodontic success and failure the anatomy of root canal system plays a significant role. As it is a complete system that branch along the lateral, apical and furcal portal of exits.1 An infected root canal system space harbours microorganisms and endotoxins2, which are primary cause of apical periodontitis.3,4 Success and failure of the endodontic treatment is related to the absence and presence of apical periodontitis, consequently the mechanical and chemical aspects of treatment are aimed at removal of these microorganisms and necrotic pulpal tissue completely from the canal system.5

The canal system is also significant because it forms an anatomical pathway for the egress of irritants beyond the apical foramen.6 Therefore, the cementodentinal junction is considered as the ideal end point of endodontic instrumentation and obturation. It creates the smallest wound site and condition for healing is best because it is the narrowest point in the canal containing the smallest diameter of blood vessels. Hence known as the minor diameter of the canal.2 The most challenging step in the root canal therapy is determining the accurate working length. It decreases the chances of damaging the periapical tissues from over instrumentation and insufficient removal of pulp and microorganisms.7

The best method for accurate working length determination is the radiographic interpretation.8 In this method, the diagnostic x-ray is used for determining the approximate tooth length. Hence the knowledge of tooth length beforehand is beneficial. Although, it is considered as a standard measure for endodontic instrumentation in the dentinal portion of root canal but it is difficult to achieve because the of variation of major foramen relation with the cementodentinal junction. Clinical errors in the working length determination can be caused by the variables in the radiographic technique, angulation.9


This descriptive study was conducted on 30 human maxillary canines. Teeth with complete root apex and sound cusp anatomy were included. Severely attrition in teeth, immature teeth, patients with cardiac pace makers, teeth with resorbed roots, teeth with roots fracture, roots with open apices patient over age of 50 and mentally handicapped patients were excluded. Only one tooth per patient was taken.

After taking the detailed medical and dental history, patients were briefed about the procedure and written consent was taken. After that a pre-operative periapical radiograph was taken. Local anaesthesia was administered and an endodontic access cavity was prepared. Pulp was extirpated with the help of H-file. Canal was properly irrigated with 5.25% sodium hypochloride. A K file 15 (Mani) was introduced to the estimated working length with the help of preoperative radiograph and apex locator and care was taken not to cross the apex. Before using the apex locator, the tooth was isolated with rubber dam. Working length radiograph was then taken with the manual x-ray parallex technique at 0.90s. (kVP 60, mAs 2). Working length from diagnostic radiograph and apex locator was then confirmed.

Sample size was calculated using anticipated population proportion with flip tip extending working length beyond the root in 28.5% cases, relative precision of 15%, confidence level of 95% and the measured sample was 30 cases.


Gender###Number###% age








###Gender###Number###Mean###Std. Deviation###p-value

Length of canine###Male###16###25.12###4.77###0.805



Total sample size comprised of 30 patients with age range from 18 years to 50 years. The mean age of study patients was 31.6 +- 8.3 years. There were 16 (53%) males and 14 (47%) females in this study. (Table 1) Majority of the study cases presented with acute (40.0%) and chronic pulpitis (36.6%). The mean working length among males and females was 25.12 mm and 24.71 mm respectfully. The difference in the maxillary canine length between males and females was not statistically significant (p-value 0.805). Further details can be seen in table 2 and 3.


For root canal therapy to be successful, the knowledge of accurate tooth length is essential. This forms the basis on which locating, cleaning, shaping and restoration of root canal is carried out.10 Previous literature shows a variation in tooth length in different races and ethnicities. The reason for this variation is genetics (e.g. sex, ethnicity) and environment. Hence, it becomes apparent that there is divergence of opinion as to the anatomy of root canal of human permanent teeth. The endodontic textbooks literature show the tooth length of the causcasian population only. However individual's ethnic origin shows a strong correlation with the dental morphology.11 It can cause discrepancy in the treatment outcomes. The failure to carry out accurate working length determination can compromise the success of procedure resulting in post treatment disease, pain and/or complication of the treated tooth.12

There is a lack of data regarding the tooth working length of South Asian populations. Retentive Maxillary canines are the longest teeth in the human dental arch, and have variation in working lengths.13 Hence maxillary canines were studied in the present research. The average working length in this study was 25.1mm, which was consistent with the value suggested in literature i.e. 26.5mm.14 A study conducted in Brazil by Cabral et al concluded that mesiodistal crown widths of maxillary and mandibular canines and premolars has shown no significant difference in black and whites.15

The maximum limit in present study was 32mm which forms 15% of our cases. This result correlates with the studies conducted by Zmener et al16 and Yousaf HA et al17 where 13.5% of teeth showed working length greater than 32mm.

Although the lengths are variable in different races, these findings suggest a common average value regardless of difference in upper and lower limits.

Some contradictory results are found in several studies in which the tooth size has been shown to have a strong association with both sex and ethnicity.18,19 Males have consistently larger teeth than females which was also the case in this study. Mesiodistal tooth dimensions of people of African descent have larger mesiodistal tooth dimensions than those of European descent.20


The average length of maxillary canines was found consistent with previous literature. On average males were found to have longer maxillary canine length than females. Present study highlights the importance of having detailed knowledge of canine root canal lengths.


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3 Nejad SM, OZGUNES H, BASARAN N. Pharmacological and Toxicological Properties of Eugenol. Turk J Pharm Sci 2017; 14(2):201-206

4 Fabris AS, Nakano V, Avila-Campos MJ. Bacteriological analysis of necrotic pulp and fistulae in primary teeth. J Appl Oral Sci 2014;22(2):118-124.

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11 Jaroontham J, Godfrey K. Mixed dentition space analysis in a Thai population. Eur J Orthod. 2000; 22:127-34.

12 Sjogren U, Hagglund B, Sundqvist G, Wing K. factors affecting the long term results of endodontic treatment. J Endod 1990; 16: 498-504.

13 Pecora JD, Neto MDS, Silva RG. Revision of internal anatomy of human teeth. Article available from http://www.odontolgia. (Accessed April 2018).

14 Carrotte P. Endodontics: Part 4 Morphology of the root canal system. Br Dental J 2004; 197: 379-383

15 Cabral ED, Barbosa JMN, Oliveira LGF. Evaluation of the need to distinguish between white and black patients in predicting the combined mesio distal crown width of canines and premolars. JAOS 2006; 14:281-5.

16 Zmener O, macchi RL, Banegas G. Canines extra-long: analysis of their frequency and disadvantages for endodontic treatment. Rev Asoc Odontol Argent 2005: 93: 13-16

17 Yousef HA, Abdullah Y.A, Asma S.A. Root canal treatment of a 32mm length maxillary caninea case report. Int J C M R 2017; 4:2297-9.

18 Ozaki T, Satake T, Kanasawa E. Morphological significance of root length variability in comparison with other crown dimensions. II. Correlation between crown and root measurements. J Nihon Univ Sch Dent 1988; 30:11-21.

19 Kim SY, Lim SH, Gang SN, Kim HJ. Crown and root lengths of incisors, canines and premolars measured by cone-beam computed tomography in patients with malocclusios. Korean J Orthod 2013; 43:271-8.

20 Smith SS, Buschang PH, Watanbe E. interarch tooth size relationships of 3 populations:'does Bolton's analysis apply?" Am J Orthod Dentofacial Orthop. 2000; 117:169-74.
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Article Details
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Author:Ijaz, Usama; Noor, Nouman; Masood, Rai Tariq; Hafeez, Resham
Publication:Pakistan Oral and Dental Journal
Article Type:Report
Geographic Code:9PAKI
Date:Jun 30, 2019

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