Objectives <p>To evaluate the influence of adipose tissue thickness on the image quality of periapical radiographs obtained using two portable X-ray devices (Díox^® and Nomad^®) compared to a non-portable X-ray device (Focus^®).</p> Methods <p>A total of 240 radiographs of the first molars from five phantoms were acquired using adipose tissue thicknesses of 0&#xa0;cm, 0.5&#xa0;cm, 1&#xa0;cm, and 1.5&#xa0;cm. Image quality was assessed using a Likert scale applied to six anatomical structures (enamel, dentin, pulp chamber, alveolar crest, trabecular bone, and periodontal ligament space), with ratings classified as “very good” (definitely suitable for diagnosis), “good” (probably suitable), “poor” (probably unsuitable), and “very poor” (definitely unsuitable). The radiographs were analyzed using the ImageJ software, evaluating grayscale values and the dynamic range in specific regions of interest in the dental crown.</p> Results <p>The Nomad^® exhibited image quality comparable to the Focus^® (<i>p</i> &gt; 0.05), while the Díox^® demonstrated inferior performance, particularly in images with 1.5&#xa0;cm of adipose tissue (<i>p</i> &lt; 0.05). The adipose tissue thickness did not affect the image quality of the Focus^® or Nomad^® but negatively impacted the Díox^® images. The Focus^® produced darker images, reflecting lower grayscale values, whereas the Díox^® had a reduced dynamic range, indicating higher contrast but fewer details in extreme areas (<i>p</i> &lt; 0.05).</p> Conclusion <p>The quality of periapical radiographic images is influenced by both the type of equipment used and the simulated adipose tissue thickness. The Nomad^® demonstrated performance comparable to the Focus^®, whereas the Díox^® exhibited lower image quality, particularly with greater adipose tissue thickness.</p>