RESUMO
The study aimed to investigate whether any correlation existed between bevel orientation and needle tip deformation following the administration of a standard inferior alveolar nerve block (IANB) technique during patient treatment. Ninety-three needles of a single brand were collected from a group of eleven similarly trained Australian dentists' following either single or dual insertion and bone contact. Specimens were examined under scanning electron microscopy at 500x, and both the direction of deformation (either towards or away from lumen) and the extent of deformation were calculated using image processing software. Results showed no correlation between bevel orientation and either the direction (P = 0.8787) or degree (P = 0.0752) of deformation. Significance was demonstrated, regardless of bevel orientation, following multiple needle use with respect to extent of needle tip deformation (P < 0.0001). A clinical recommendation can be made that the dental needle should be routinely replaced when subsequent injections are required during the delivery of a typical IANB.
