RESUMEN

Objectives: To compare the cone-cutting error frequency and the X-ray cone alignment time in the horizontal tube-shift technique between the newly designed angulation-adjustable and the extension cone paralleling (XCP) holders, by dental students. Materials and methods: Two film holders were assigned for a random test. The mandibular left first molar position of a laboratory phantom head was used. Intraoral periapical radiography was performed horizontally at right-angle, 20° mesial-, and 20° distal projections by fifth-year dental students (n = 41). The cone-cutting error frequency and the X-ray cone alignment time were measured and analyzed statistically at a significant level of p < 0.05. Results: Using the two holders at right angle caused no significant difference (p > 0.05) in the cone-cutting error frequency or the X-ray cone alignment time. At the horizontal tube-shift angles, some significantly greater frequencies of cone-cutting errors at both 20° mesial (43.9%) and 20° distal (73.2%) shifts were detected in the XCP group, but none in the angulation-adjustable group. For X-ray cone alignment time at both 20° mesial and 20° distal shifts, the XCP group spent a significantly longer time (p < 0.05) than the angulation-adjustable group. Conclusions: The usages of the angulation-adjustable holder in the horizontal tube-shift technique resulted in none of the cone-cutting error and a significant reduction of time for the X-ray cone alignment, when compared to those of the XCP instrument. Clinical significance: The angulation-adjustable holder effectively reduced cone cutting error and treatment time, both of which were beneficial to the patients and the dental personnel.