*3.2. Relevant Data of Included Studies*

All of the included manuscripts were published between 2013 and 2020. Table 2 details the main characteristics of those included in the manuscript.

According to Table 2, the number of studies published increased each year and most of them were published in 2019. Selected works were published across seven countries, most of them in the United States (*n* = 5) and England (*n* = 5).

Regarding the variables detected by the included studies, the variable of teeth was the most analyzed (*n* = 9) followed by variable caries (*n* = 7). No studies detecting variables of dental implants and filled teeth were found. Only two studies investigated endodontic applications.

The total image database varied from 52 to 9812 images, with a mean of 1379 images. Panoramic radiographies were the most common image employed (*n* = 7) followed by periapical images (*n* = 3). Near-infrared light transillumination images were employed in two studies and bitewing and CT and radiovisiography were each employed in one study. No image type was detailed in two of the studies.




