Comparison of two needle models in terms of bevel deformation during truncal block of the inferior alveolar nerve.

OBJECTIVES To evaluate the differences in terms of bevel deformation between two types of needle of the same length and external caliber, but with different internal diameters, during truncal block of the inferior alveolar nerve. STUDY DESIGN Four operators performed truncal block of the inferior alveolar nerve and infiltrating anesthesia of the buccal nerve for the extraction of a lower third molar in 266 patients. The truncal block was carried out using a standard 27G x 35 mm needle with an internal caliber of 0.215 mm, or a 27G x 35 mm XL Monoprotect needle with an internal caliber of 0.265 mm. The infiltrating anesthesia was made with a Monoprotect or XL Monoprotect needle, both with a caliber of 30G and a length of 25 mm, but with different internal calibers (0.215 and 0.265 mm, respectively). The type of needle used, the anesthetic technique and the number of bone contacts was established during the procedure, the operator working side, the side of the tooth to be removed, the operator in charge of the intervention and the presence of bevel deformation after the anesthetic technique were collected for each patient. RESULTS A statistically significant association was observed between bevel deformation and the operator performing the truncal block, while a statistically significant association (p use <0.05) was recorded between bevel deformation and the operator performing the infiltrating technique, the internal caliber of the needle and the number of bone contacts. CONCLUSIONS There are no differences between the Monoprotect needles and the XL Monoprotect needles in terms of bevel deformation. Any such deformation can be attributable to physical -mechanical aspects such as the force with which the operator inserts the needle in the tissues- an aspect that in turn conditions the intensity of needle impact upon bone.