Objective. Second-generation force-controlled periodontal probes were developed to address examiner-related factors in the application of standard forces while probing. However, previous researches comparing the accuracy of first and second-generation probes have failed to yield unequivocal results. This study aimed to determine the accuracy and reproducibility of a first-generation UNC-15 probe and force-controlled Gram probe #2, used by senior and junior dental students in measuring probing pocket depths (PPD).

Methods. Eight senior and eight junior dental students participated in the study. A periodontal model was positioned on a digital balance. Each participant performed probing four times, twice using a UNC-15 and twice employing a Gram probe #2. The order of probe usage was randomly assigned. The PPD and probing forces employed were recorded initially and after a 15-minute interval. Data were analyzed using a t-test at a 0.05 significance level.

Results. Both junior and senior students used significantly higher probing forces (35.3 ± 1.4 and 29.9 ± 2.1 g, respectively) than the standard 25 g when using the UNC-15 probe. The junior students employed accurate forces using the Gram probe while probing both anterior (25.6 ± 1.2 g) and posterior teeth (25.1 ± 0.7 g). In comparison, the seniors used accurate forces (26.0 ± 1.3 g) only while examining anterior teeth. The PPD values obtained by both student groups were comparable to the actual PPD, except for significantly higher measurements (P=0.0003) obtained by juniors when examining posterior teeth using the Gram probe. When assessing the reproducibility of PPD measurements obtained from two examinations, values were reproducible for both juniors and seniors when using the Gram probe and during an inspection of posterior teeth using the UNC-15 probe.

Conclusions. The Gram probe #2 had better reproducibility and yielded forces closer to the standard 25 g. However, more accurate PPD values were obtained with the UNC-15 probe.