Can tongue shadow in panoramic radiographs be avoided by using the tongue repositioning maneuver?

The purpose of this study was to evaluate the use of the tongue repositioning maneuver (TRM) during panoramic radiography so as to avoid the error of tongue shadow.

A total of 300 panoramic radiographs were evaluated. One hundred and fifty orthopantomograms with conventional positioning technique were used as a control group, while other 150 were taken with the patient performing the TRM. The tongue shadow was measured in each radiograph in the first molar regions bilaterally and in the midsagittal plane. Wilcoxon Mann-Whitney U-Test was used to test the significance difference between the groups.

The tongue-palate distance in the study group was reduced from a mean value of 6.4 mm to 1 mm in the right first molar, 8.0 mm to 2.2 mm in the midsagittal region, and 6.6 mm to 1.2 mm in the left first molar position. Statistical evaluation exhibited significant differences of tongue shadow at all measuring sites between study and control group (P < .0001).

The present study demonstrates that the TRM leads to a substantial reduction of the tongue position error in panoramic radiography.