Positive Predictive Value of Panoramic Radiography for Assessment of the Relationship of Impacted Mandibular Third Molars with the Mandibular Canal Based on Cone-Beam Computed Tomography: A Cross-Sectional Study.

Maryam Tofangchiha,Ahad Alizadeh,Soheil Koushaei,Zahra Souri,Maryam Mortazavi,Romeo Patini

doi:10.3390/diagnostics11091578

Maryam Tofangchiha, Ahad Alizadeh + Show 4 more

Open Access

https://doi.org/10.3390/diagnostics11091578

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Abstract

The aim of the present study was to assess the positive predictive value (PPV) of panoramic radiographic signs in the assessment of the relationship between impacted mandibular third molars (IMTMs) and the mandibular canal (MC). This cross-sectional study was conducted by reviewing 102 cone-beam computed tomography (CBCT) and panoramic radiographs of patients with IMTMs and radiographic signs of the contact of the IMTMs with the MC on panoramic radiographs (i.e., root apex darkening and interference with the white line). A positive relationship of the IMTM roots with the MC based on CBCT findings was recorded as the gold standard. The PPV of panoramic radiographic signs was calculated for the detection of the relationship of the IMTM root with the MC. The IMTMs were in contact with the MC on CBCT scans in 90.1% of the cases. The PPV of root apex darkening and the interference with the white line was found to be 89.09% (95% CI: (77.75, 95.88)) and 91.48% (95% CI: (79.62, 97.63)), respectively. The MC had a buccal position in 63.7%, and a lingual position in 35.2%, of the cases. The contact of IMTMs with the MC was more commonly seen in patients with a lingual position (100% of the samples). The IMTM root apex darkening and interference with the white line of the MC on panoramic radiographs had a high PPV for determination of the contact of IMTMs with the MC. Thus, presence of the above-mentioned risk factors indicates the need for subsequent 3D radiographic assessments.

Highlights

The risk factors for the contact of the mandibular canal (MC) with the impacted mandibular third molars (IMTMs) on panoramic radiographs should be recognized for more accurate diagnosis, and more advanced imaging modalities should be requested in case of the presence of risk factors
The logistic regression test showed that the two panoramic radiographic signs evaluated in this study reliably revealed the contact of IMTMs and the MC, as confirmed by cone-beam computed tomography (CBCT), and that the frequency of contact was higher in the lingual position of the MC when compared with the buccal position (p = 0.013)
In assessment of the positive predictive value (PPV) of the root darkening radiographic sign, the results showed the agreement of this panoramic radiographic sign and the CBCT findings in 89.09%

Summary

Introduction

The proximity of the mandibular canal (MC) to the IMTM root is the most important factor responsible for IAN damage. Dental radiography is a suggested diagnostic modality to prevent such complications [2]. Radiography can provide valuable information regarding the size, shape, and branching of the MC; orientation of the IMTM root (s); proximity to the adjacent anatomical structures; and complications related to third molar impaction [3]. Preoperative radiography is imperative to enhance the process of tooth extraction and to estimate and minimize the risk of IAN damage [4]. Evidence of the contact of the IMTM root and the MC on panoramic radiographs can serve as a risk factor for IMTM surgery and postoperative complications. The risk factors for the contact of the MC with the IMTMs on panoramic radiographs should be recognized for more accurate diagnosis, and more advanced imaging modalities should be requested in case of the presence of risk factors

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