J Korean Assoc Oral Maxillofac Surg.  2015 Apr;41(2):66-73. 10.5125/jkaoms.2015.41.2.66.

Validity of the vertical tube-shift method in determining the relationship between the mandibular third molar roots and the inferior alveolar nerve canal

• Arora A
• Patil BA
• Sodhi A

• KMID: 2189465
• DOI: http://doi.org/10.5125/jkaoms.2015.41.2.66

Abstract

OBJECTIVES
To assess the validity of the vertical tube-shift method using intraoral periapical radiography (IOPAR) for determining the relationship between the mandibular third molar roots and the inferior alveolar nerve (IAN) canal in comparison with cone-beam computed tomography (CBCT).
MATERIALS AND METHODS
Fifty impacted mandibular third molars were analyzed using the IOPAR vertical tube-shift method and CBCT. The relationship of the IAN canal to the impacted mandibular third molar was recorded as buccal, lingual or in line with the apex and was compared with CBCT findings. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the vertical tube-shift method in depicting the relationship (buccal/lingual/in line with the apex) of the IAN canal to the third molar root apex was calculated.
RESULTS
The sensitivity and specificity PPV and NPV of the IOPAR vertical tube-shift technique was found to be highest for a lingual relationship (100%) followed by buccal (94.4%, 92.3%, 97.1%, and 85.7%) and in line with the apex relationship (88.9%, 95.0%, 80.0%, and 97.4%) of the IAN canal with the third molar root apex, respectively. A statistically significant association was observed between the IOPAR vertical tube-shift method and the CBCT with a P-value <0.01.
CONCLUSION
The vertical tube-shift method can be used as an effective diagnostic tool in assessing the relationship of the IAN canal to the third molar root apex with high sensitivity, specificity, PPV, and NPV.

Keyword

Third molar; Inferior alveolar nerve; Vertical tube-shift method; Cone-beam computed tomography

MeSH Terms

Cone-Beam Computed Tomography
Mandibular Nerve*
Molar, Third*
Radiography
Sensitivity and Specificity

Figure

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  Fig. 1 Intraoral periapical radiography exposure was made by directing the position-indicating device at 0° (A) and -20° (B) vertical angulations. Informed consent was obtained from patient willing to participate in the present study.

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  Fig. 2 A. Intraoral periapical radiography at 0°, -20° by vertical tube-shift method and their tracing showing the inferior alveolar nerve (IAN) canal moving upwards predicting the canal as buccal to the third molar root apex. B. Cone-beam computed tomography of the same patient as in Fig. 2A, showing the IAN canal buccal to the third molar root apex.

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  Fig. 3 A. Intraoral periapical radiography at 0°, -20° by vertical tube-shift method and their tracing showing inferior alveolar nerve (IAN) canal moving downwards predicting canal lingual to the third molar root apex. B. Cone-beam computed tomography of the same patient as in Fig. 3A, showing the IAN canal lingual to the third molar root apex.

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  Fig. 4 A. Intraoral periapical radiography at 0°, -20° by vertical tube-shift method and their tracing showing no change in the inferior alveolar nerve (IAN) canal position relative to the third molar root apex. B. Cone-beam computed tomography of the same patient as in Fig. 4A showing no change in the IAN canal position relative to the third molar root apex.

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