Contributions of reformatted computed tomography and panoramic radiography in the localization of third molars relative to the maxillary sinus

BACKGROUND A serious complication of surgical removal of impacted lower third molars is inferior alveolar nerve (IAN) injury. Evaluation of radiographic factors to predict IAN injury using CT and panoramic radiography includes root morphology assessment, follicular sac size, mandibular bone density, inferior alveolar nerve and vessels, condition of the overlying tissues, relation of the impacted tooth with the body and ramus of the mandible and the adjacent teeth. This study was done to evaluate the radiological features of the impacted lower mandibular teeth and their relationship with IAN through panoramic radiography and CT and to assess the most predictable radiological criteria for inferior alveolar nerve injury in impacted third molar surgery. METHODS All the patients indicated for lower third molar extraction were included in the study and pre-operative conventional panoramic radiographs (Planmeca Proline PM 2002 CC, Helsinki, Finland) and CBCT (Kodak CBCT) were taken. Any post-operative nerve injuries detected were followed up after 15 days or 1 month. Fisher’s exact test was done to find the association between the outcome variable and explanatory variables. RESULTS Only 11.4 % (N = 4) of all participants had IAN injury following surgical disimpaction. All the participants with IAN injury showed narrowing of the canal on their preoperative panoramic radiographs and presence of nerve approximation with the tooth in cone beam computed tomography (CBCT) reports (P < 0.05). CONCLUSIONS A statistically significant association exists between IAN injury and nerve exposure, radiographic signs of nerve involvement for panoramic radiograph, level of third molar impaction, and nerve approximation in CBCT. KEY WORDS Inferior Alveolar Nerve Injury, Lower Third Molar Impaction, Panoramic Radiography, CBCT

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Accuracy of panoramic radiography in diagnosing maxillary sinus-root relationship: A systematic review and meta-analysis

The Angle Orthodontist ◽

10.2319/022018-135.1 ◽

2018 ◽

Vol 88 (6) ◽

pp. 819-829 ◽

Cited By ~ 1

Author(s):

Wentian Sun ◽

Kai Xia ◽

Li Tang ◽

Chenlu Liu ◽

Ling Zou ◽

...

Keyword(s):

Computed Tomography ◽

Maxillary Sinus ◽

Panoramic Radiography ◽

Positive Likelihood Ratio ◽

Display Type ◽

Type I ◽

Type Ii ◽

Root Tips ◽

Type Iv ◽

Good Ability

ABSTRACT Objective: To investigate the accuracy of panoramic radiography (PR) in diagnosing maxillary sinus-root relationships (SRRs). Materials and Methods: PubMed, EMBASE, CENTRAL, Web of Science, ScienceDirect, CBM, Baidu Scholar, and SIGLE were searched. The studies comparing the diagnostic accuracy of PR and computed tomography/cone-beam computed tomography (CT/CBCT) for SRR were included. Results: Eleven studies were included. Meta-analyses showed that, for type I SRR, PR had the highest specificity, positive likelihood ratio (+LR), diagnostic odds ratio (DOR), and area under the curve (AUC), with a high sensitivity and a low negative LR (−LR). For type IV, PR had a high DOR and AUC, with the highest sensitivity but a low +LR, the lowest –LR, and the lowest specificity. For type II, PR had the lowest AUC, with a low sensitivity, +LR, and DOR and a high −LR. For type III, PR had the lowest sensitivity, +LR, and DOR and the highest −LR. The distance from root tips to the maxillary sinus floor on PR was significantly longer (mean difference: −1.88 mm; 95% confidence interval: −2.19 to −1.57; P < .0001) than that on CT/CBCT. Conclusions: Currently available evidence suggests PR could be reliable for detecting type I SRR. PR has a good ability to confirm true type IV SRR but a poor ability to rule out false type IV SRR. For type II and III SRR, PR shows poor accuracy and tends to overestimate the extent of protrusion of the roots into the maxillary sinus. When PRs display type II, III, or IV SRR and related treatment is needed, CBCT should be used for further examinations.

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