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ORIGINAL ARTICLE
Year : 2017  |  Volume : 7  |  Issue : 3  |  Page : 166-169

Comparative evaluation of second mesiobuccal canal detection in maxillary first molars using magnification and illumination


Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences, Mangalore, Karnataka, India

Date of Web Publication21-Aug-2017

Correspondence Address:
Karthik Shetty
Department of Conservative Dentistry and Endodontics, Manipal College of Dental Sciences Manipal University, Light House Hill Road, Mangalore - 575 001, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1658-5984.213483

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  Abstract 

Aim: This in vitro study evaluated the effectiveness of detecting the presence of second mesiobuccal (MB2) canal in the maxillary first molars, using magnification and illumination.
Materials and Methods: Access cavities of fifty extracted human maxillary first molars were prepared, and the floor of the pulp chamber was then explored to locate the MB2 canal in five stages: Stage I (direct vision), Stage II (under ×2.5 magnifying loupes without light-emitting diode [LED] light), Stage III (under ×2.5 magnifying loupes with LED light), Stage IV (under operating microscope at ×5), and Stage V (under operating microscope at ×12.8).
Statistical Analysis: The descriptive statistics were tabulated using the kappa statistic to check the association between the five groups.
Results: The operating microscope at ×5 and ×12.8 gave a diagnostic accuracy of 100%, followed by magnifying loupes with LED light which gave a diagnostic accuracy of 90% in detecting the presence of MB2 canal. The use of magnifying loupes without LED light and plain eyesight gave a comparatively lesser diagnostic accuracy, i.e., 76% and 68%, respectively.
Conclusion: The operating microscope with a sensitivity and diagnostic accuracy of 100% was most effective in the detection of MB2 canals followed by magnifying loupes with LED light.

Keywords: Light-emitting diode light, magnifying loupes, maxillary first molar, second mesiobuccal canal, operating microscope


How to cite this article:
Nath KS, Shetty K. Comparative evaluation of second mesiobuccal canal detection in maxillary first molars using magnification and illumination. Saudi Endod J 2017;7:166-9

How to cite this URL:
Nath KS, Shetty K. Comparative evaluation of second mesiobuccal canal detection in maxillary first molars using magnification and illumination. Saudi Endod J [serial online] 2017 [cited 2017 Nov 22];7:166-9. Available from: http://www.saudiendodj.com/text.asp?2017/7/3/166/213483


  Introduction Top


Over the past few years, there has been some immense research that has been carried out in relation to the mesiobuccal (MB1) root of the maxillary first molar mainly because of the additional root canal it often possesses, i.e., second mesiobuccal (MB2) canal.[1],[2] This canal often goes unnoticed, which can be attributed to the fact that it departs the pulp chamber at a sharp mesial inclination and is then bent again in the distal direction, making its detection highly challenging.[3] Likewise, difficulty and inability to identify the MB2 may often result in a high percentage of endodontic failure among these teeth.[4] Studies have shown that endodontically retreated teeth contained more undetected MB2 canals than teeth which were treated for the first time, thereby leading to a high endodontic failure rate among these teeth.[5],[6]

Using magnification during endodontic treatment has increased in practice that considerably increases the precision level of the procedure during troughing and searching for canal orifices on the floor of the pulp chamber of premolar and molar teeth, thereby significantly reducing the risk of creating perforations and other mishaps.[7]

The purpose of this study was to investigate the effectiveness in detecting the presence of MB2 canals in maxillary first molars using plain eyesight, magnifying loupes, and operating microscope and also to investigate the effect of light-emitting diode (LED) illumination in detecting the same.


  Materials and Methods Top


The study was conducted in the Department of Conservative Dentistry and Endodontics at the Manipal College of Dental Sciences, Mangalore. Ethical approval for the study was obtained by the Institutional Ethics Committee of Manipal College of Dental Sciences, Mangalore.

In the present study, fifty permanent maxillary first molars were collected and mounted in cast stone. The inclusion criteria were maxillary first molar with three roots of fully formed apices and not endodontically treated. The age of the patients when the teeth were extracted ranged from 30 to 60 years. The teeth were accessed with sterile Endo Access Bur (Dentsply-Maillefer, Ballaigues, Switzerland). The access cavity was prepared initially with triangular outline. MB1, distobuccal, and palatal (P) canal orifices were located with the help of an endodontic explorer (DG16, Hu-Friedy), and canals were negotiated with 10 or 15 K-files (Dentsply-Maillefer, Ballaigues, Switzerland). Hand instrumentation followed by copious irrigation with 3% sodium hypochlorite (Parcan; Septodont, Saint-Maur-des-Fosses, France) was used to remove the contents within pulp chamber and root canal space. The outline of the access cavity was further improved from a triangular to a rhomboidal shape to increase the visibility of the pulpal floor.

The pulp chamber floor was then negotiated to locate the MB2 canal in five stages.

Stage I (direct vision)

Initially, the MB2 canal orifice was located with a DG16 explorer under direct vision. The explorer was run from the main MB1 canal toward the palatal canal 1–2 mm mesially.

Stage II (under magnifying loupes without light-emitting diode light)

The teeth which did not detect the presence of MB2 canal after Stage I were examined under magnification (×2.5) using Dental Loupes (Heine HR/HRP, Germany) without LED light with the help of a DG16 explorer.

Stage III (under magnifying loupes with light-emitting diode light)

Further, the teeth in which the MB2 canal could not be detected after Stage II, Dental Loupes (Heine HR LED HQ, Germany) attached to an LED light source was used.

Stage IV (under operating microscope ×5)

MB2 canal which was not traced after Stage III, Operating Microscope at ×5 magnification (Seiler Evolution xR6, USA) was used.

Stage V (under operating microscope ×12.8)

The teeth in which MB2 canal was not located after Stage IV, Operating Microscope at ×12.8 magnification (Seiler Evolution xR6, USA) was used.

The teeth which could not detect the MB2 canal after Stage V were reported to be absent or missing.

Throughout the procedure, copious irrigation was done with 3% sodium hypochlorite solution and normal saline intermittently. After locating the canal orifice, the MB2 canal was negotiated using 06, 08, and 10 K-files. The presence of MB2 canal located was confirmed with working length determination radiographs.

Statistical analysis

The data were analyzed using the SPSS software 17.0 version (IBM Corp, Armonk, NY, USA). The descriptive statistics were tabulated using the kappa statistic to check the association between the five groups. The kappa value ranges from 0 to 1, and a kappa value >0.6 was regarded to have excellent diagnostic accuracy.


  Results Top


The number of teeth in which MB2 canal was found has been shown in [Table 1].
Table 1: Number of teeth in which second mesiobuccal canals were detected in each stage

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The operating microscope tested at ×12.8 rendered a diagnostic accuracy of 100% (kappa = 1) in detecting the presence of MB2 canal [Table 2]. Within the limitations of our study, the operating microscope at ×12.8 was taken as gold standard and compared with the rest of the groups. The operating microscope at ×5 gave a diagnostic accuracy of 100% (kappa = 1) as well, followed by magnifying loupes with LED light which gave a diagnostic accuracy of 90% and a kappa = 0.8. The use of magnifying loupes without illumination and plain eyesight gave a comparatively lesser diagnostic accuracy, i.e., 76% and 68%, respectively and a kappa <0.6. The use of magnifying loupes with LED light showed a statistically significant difference in the diagnostic accuracy of MB2 canals (kappa >0.6) when compared to loupes without LED light. The operating microscope (×5 and ×12.8) and magnifying loupes with LED light did not show any significant difference in the diagnostic accuracy of MB2 canals.
Table 2: Statistical results

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  Discussion Top


The permanent maxillary 1st molars are one of the most frequently endodontically treated teeth.[6] Seidberg et al.[8] in their in vitro study reported the incidence of MB2 canal in maxillary molars to be about 62%. In the current study, the MB2 canal was detected in about 54% of the teeth at the highest magnification which was fairly comparable to the studies done by various authors as shown in [Table 3].
Table 3: Incidence of second mesiobuccal canal in the maxillary first molar as reported by various authors

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Furthermore, the failure rate among these teeth has been regarded to be high due to missed and incomplete preparation of the MB2 canal.[6]

Various techniques have been applied to enable the identification of MB2 canals, such as modification in the access cavity preparation, use of digital radiography technology, or contrast media.[13],[14] Access cavity modifications and canal detection techniques, in combination with technological advancements in magnification and illumination, have greatly assisted in the detection and treatment of the MB2 canals.[15] In addition, to the use of bur and explorers to search out the additional hidden orifices, endodontic ultrasonic tips are now commonly employed for the same purpose.[16]

The success rate of all these efforts combined has been considerably low, whereas with the aid of magnification, the frequency of locating MB2 canals has been greatly enhanced.[3],[17] Alaçam et al.[16] proposed that operating microscope and ultrasonics when used together effectively increased the identification of MB2 canals in permanent maxillary first molars. Buhrley et al.[18] in their study showed that the use of magnification increased MB2 detection rate by almost three times when compared to that of non-magnification. Schwarze et al.[9] compared the differences in magnifying loupes and operating microscope for the detection of MB2 canals in maxillary molars and found that while 41.3% of those canals were found using magnifying loupes, the operating microscope showed the MB2 canal in 93.7% of the cases. Al-Habboubi and Al-Wasi [19] in their study stated that the detection of extra canals was enhanced with the use of magnification and illumination. Similarly, when compared to the present study, the increase in magnification effectively increased the rate of detection of MB2 canal and also the importance of LED illumination in detecting the same was highlighted.

The operating microscope was most accurate in the detection of MB2 canal. The magnifying loupes when used with LED light (40.000 LUX/420 mm distance) efficiently detected the presence of MB2 canals with a diagnostic accuracy of 90% which was excellent. However, the efficiency in the detection of MB2 canal decreased when examined under plain eyesight and without the use of LED light. These results impressively indicate the benefits of magnification and LED illumination. However, in 46% of teeth (i.e., 23 teeth), MB2 canals still remained unidentified. This could likely be due to diffuse calcifications, debris, or missing MB2 canals.

There is another key factor which needs to be taken into account during the identification of MB2 canal, i.e., “The Resolving Power of Human Eye.” Resolution is nothing but the ability to distinguish two objects that are very close together, are two distinct objects rather than a single object. The human eye can visualize and resolve two objects that are about 0.2 millimeters apart – anything less than that, and the two objects are seen as a single shape. Whereas under an operating microscope, the resolution limit increases from 0.2 mm to 0.006 mm, a massive improvement.[20] This theory can be applied in the detection of MB2 canal. The distance between MB1 and MB2, anything less than one-fifth (i.e., 0.2 mm) of a millimeter, it becomes extremely difficult for the human eye to resolve them as two separate canals and that's where the role of magnification comes into play. Furthermore, the intensity of light from the microscope is much higher than that what is possible from the loupe, and the nature of the delivery is coaxial in the former. This allows for a better illumination of the field and hence greater visibility.


  Conclusion Top


The operating microscope was most effective in the detection of MB2 canals. Furthermore, the magnifying loupes with LED light when compared to the operating microscope did not show a significant difference in the detection of MB2 canals, suggesting that magnifying loupes with LED light can be used as a suitable alternative to operating microscope.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

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8.
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Schwarze T, Baethge C, Stecher T, Geurtsen W. Identification of second canals in the mesiobuccal root of maxillary first and second molars using magnifying loupes or an operating microscope. Aust Endod J 2002;28:57-60.  Back to cited text no. 9
    
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[PUBMED]  [Full text]  
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Weller RN, Hartwell GR. The impact of improved access and searching techniques on detection of the mesiolingual canal in maxillary molars. J Endod 1989;15:82-3.  Back to cited text no. 15
    
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  [Full text]  
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    Tables

  [Table 1], [Table 2], [Table 3]



 

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