Evaluation of a new periodontal probe tip design. A clinical and in vitro study.

Abstract

In the search for an accurate periodontal probe which does not frequently penetrate the pocket base, a new tip has been designed which is flattened, and of 1 mm width and 0.45 mm thickness. This study aimed to evaluate the physico-mechanical and clinical properties of this probe (test) in comparison to a conventional 0.5 mm circular probe (control). Photoelastic stress analysis was undertaken for test and control probe tips at 3.15 and 5 N loads. To assess probing validity, the clinical probing depth with each probe (0.25 N force) at 125 sites on 27 teeth (27 subjects), was compared with the post-extraction connective tissue level measurement. Also evaluated were probing reproducibility (1200 sites in 25 subjects) and patient comfort (30 subjects). Using photoelastic stress analysis, the test probe demonstrated lower stresses and less local stress concentration than the control. Clinically, the test probe measured close to the post-extraction gold standard in greater frequency than the control - 26 versus 11 readings (21% versus 9%) exactly matched, and 90 versus 67 (72% versus 54%) were within +/-0.5 mm of the laboratory measurement. The test probe was, on average, 0.13 mm coronal to the connective tissue attachment level, whereas the control penetrated 0.27 mm past this level. The intraclass correlation between clinical and laboratory readings was greater for the test than the control (r=0.81 and 0.74, respectively). Although the control probe overestimated probing depth more markedly at bleeding (0.41 mm) than at non-bleeding (0.15 mm) sites, the relative position of the test probe hardly differed with inflammatory status (-0.11 and -0.14 mm, respectively). Each probe demonstrated good clinical reproducibility. However, the test probe examination was more comfortable for the patient. This new periodontal probe tip appears to have greater validity, good reproducibility and produces less patient discomfort.