Vertical angulation mandibular first premolar tolerance in periapical projection radiography

Abstract

One evaluation criterion of a radiograph is vertical distortion, which is relatively more common in periapical radiographs of the mandibular premolar region. This study determined the vertical angle changes that can be tolerated in periapical radiographs of mandibular premolars. The lengths of 30 already extracted mandibular first premolars were measured clinically and radiographically. Periapical radiography projections were obtained with vertical angles set at 0⁰, +10⁰, +15⁰, +20⁰, −10⁰, −15⁰, and −20⁰. Then, tooth length and the difference in cusp height were measured by two observers twice at different times. There was no significant difference in tooth length at vertical angulations of 0⁰, +10⁰, +15⁰, +20⁰, −10⁰, and −15⁰ (P > 0.05). On the other hand, a significant difference was noted in the buccal-lingual cusp difference (P < 0.05). In standard periapical radiography, a 10⁰ change from the normal vertical angulation could be tolerated still to measure the vertical dimension or tooth length of the mandibular first premolar tooth.