Locating mandibular foramen in children of different age groups using panoramic radiography

Introduction
Inferior alveolar nerve block (IANB) is the most widely used local anesthesia technique for mandibular primary or permanent teeth. The success of an adequate and effective nerve block with this technique depends on deposition of local anesthetic solution near mandibular foramen (MF), located on the medial side of mandibular ramus.

Objectives
The purpose of the study was to investigate the relative position of MF using digital panoramic radiographic technique to provide data for IANB technique in children.

Material and methods
This retrospective study consisted of digital panoramic radiographs from 200 children, aged 5-14 years. Panoramic radiographs were divided into 5 groups according to Hellman dental classification. The distance of MF to occlusal plane, anterior border of the ramus, and lower border of the mandible were measured using computer software in different age groups, and then compared to determine the position of MF on radiographs. One-way analysis of variance test, which is one of the parametric tests, was used to compare mean values between the groups.

Results
While MF was 0.85 mm above the occlusal plane in Hellman IIC age group, this distance increased with age progression, and there was a statistically significant difference between age groups. The distance from MF to anterior edge of the ramus and lower plane of the mandible increased in Hellman IVA age group, and there was a statistically significant difference between age groups.

Conclusions
The position of MF in panoramic radiographs gradually changed posteriorly and upwards on the ramus with age progression.