Are colored periodontal probes reliable to classify the gingival phenotype in terms of gingival thickness?

Abstract

Background: This cross-sectional study assessed the potential of colored periodontal probes (CPP) to classify gingival phenotype in terms of gingival thickness (GT). Methods: Buccal GT in three anterior teeth in each of 50 patients was measured by transgingival sounding and classified by three different methods by eight examiners. Specifically, the diagnostic potential of visual judgment and transparency of a standard periodontal probe (SPP) to discriminate thin and thick gingiva, and of CPP to discriminate thin, medium, thick, or very thick gingiva was assessed.Results: GT ranged from 0.57 to 2.37 mm. Using CPP resulted in a medium judgment in 87% of the cases, on average, and only between 1-10 cases/examiner were judged as thick or very thick. Considering 1 mm GT as relevant cut-off value, all methods showed a high positive predictive value (≥ 0.82) to identify thick cases, but also a high false omission rate (≥ 0.73) indicating that many cases classified as thin were actually thick. Further, 88% of the cases being ≤ 1 mm, were not classified as thin with CPP; this was inferior to SPP, for which, however, still 64% of the cases being ≤ 1 mm thick were wrongly classified. The highest, yet moderate agreement among examiners was achieved by SPP (κ = 0.427), whereas visual judgment and CPP showed only fair (κ = 0.211) and slight agreement (κ = 0.112), respectively. Conclusion:Using CPP resulted in most of the cases in a medium judgment. It seems that CPP cannot distinctly discriminate between "thick" and "very thick" cases and fails to capture the thin high-risk cases.

Gingival landmarks and cutting points for gingival phenotype determination: A clinical and tomographic cross‐sectional study

“…It is also important to consider a higher predictability in the determination of GP by TRAN with a standard periodontal probe than that with a color-coded probe, compared with direct measurement of GT by transgingival probing. 2 In addition, in the surgical treatment of gingival recession by coronally advanced flaps, the results of medium, thick, and very thick were not statistically different, with the highest complete root coverage found in the thick group. 37 The various GLs and methods for GP evaluation used in the studies make comparisons almost impossible.…”

“…Moreover, the predictability of detecting thin and thick GP considering the CPs of 0.6 and 1.2 mm, was different from the 100% found in the former study. 3 It is important to highlight that in previous studies, 2,3,8,20,34 the reliability of TRAN compared with direct measurements of GT showed different results of a correct determination of thin and thick GPs. Direct comparisons of these data are difficult to perform, which may be partially explained by the fact that despite adopting the same CP of 1 mm, multiple landmarks and different methods of evaluating the GT were used, resulting in a large variation of thickness across the studies, ranging from 0.50 to 1.44 mm.…”

“…1 A clinical trial involving 100 periodontally healthy subjects indicated that TRAN was reproducible, with a Kappa of 0.70, that represents a moderate agreement between duplicate examinations. 28 However, it is also a subjective method, and its accuracy depends on the examiner's experience, 2 and other factors, such as light conditions, use of magnification, and evaluation in photographic exams. 28,29 Studies on the TRAN method may not be easily comparable since various probe designs were used.…”

“…28,29 Studies on the TRAN method may not be easily comparable since various probe designs were used. 2 It is also important to highlight that probe visibility have been tested in samples of subjects with unknown gingival pigmentation. 1 It is unknown if the same outcomes are to be expected in populations with different gingival pigmentation.…”

“…Direct comparisons of these data are difficult to perform, which may be partially explained by the fact that despite adopting the same CP of 1 mm, multiple landmarks and different methods of evaluating the GT were used, resulting in a large variation of thickness across the studies, ranging from 0.50 to 1.44 mm. 2,3,8,20,34 Furthermore, different results of the comparison of TRAN with direct measurements were expressed, such as positive and negative predictive values, true and false positive rates, false omission rate, and agreement, which can make the comparison between studies even more difficult.…”