Validity and Reliability of Polarized vs Non-Polarized Digital Images for Measuring Gingival Melanin Pigmentation

Figures & data

Figure 1 Comparative visualization of (A) non-polarized and (B) polarized images. Image (B) highlights the absence of flash reflection on the polarized side.

Figure 2 Standardized photos were taken with a stent and a marker to ensure the same position and angle when the images were overlayed over each other.

Figure 3 Picture of the full upper arch after gingival depigmentation.

Figure 4 The grid feature in Photoshop 2020 was used to divide each image into numerous smaller samples.

Figure 5 Measurement of gingival pigmentation with the Dummett Oral Pigmentation Index (DOPI) and Gingival Melanosis Record (GMR).

Figure 6 Percentage of GMR of polarized and non-polarized photos among different groups at pre- and post-depigmentation.

Abbreviations: GD, general dentist; Ortho, orthodontist; GMR, Gingival Melanosis Record.

Figure 7 DOPI mean of polarized and non-polarized photos among different evaluators at pre-depigmentation and post-gingival depigmentation.

Abbreviations: GD, general dentist; Ortho, orthodontist; DOPI, Dummett Oral Pigmentation Index.

Table 1 Comparison of GMR and DOPI Before and After Depigmentation by Different Evaluators

Time	Outcome Measures	Evaluator	Significance Test (2- Tailed)	Mean Difference	Standard Error Difference	95% Confidence Interval of the Difference
						Lower	Upper
Pre	DOPI	Ortho	0.876	0.02	0.18	−0.35	0.41
		Lay person	0.586	−0.12	0.23	−0.61	0.35
		GD	0.783	−0.07	0.25	−0.61	0.47
Post		Ortho	0.720	0.03	6.00	−0.18	0.26
		Lay person	0.994	−0.00	0.17	−0.36	0.35
		GD	0.548	−0.09	0.15	−0.42	0.23
Pre	GMR	Ortho	0.992	−0.02	2.16	−4.57	4.53
		Lay person	0.429	−4.41	5.45	−15.88	7.05
		GD	0.988	−0.10	6.77	−14.33	14.12
Post		Ortho	0.597	3.95	7.36	−11.50	19.42
		Lay person	0.728	3.49	9.91	−17.32	24.32
		GD	0.902	−1.27	10.19	−22.69	20.13

Abbreviations: GD, general dentist; Ortho, orthodontist; DOPI, Dummett Oral Pigmentation Index; GMR, Gingival Melanosis Record.

Figure 8 Percentage of GMR reduction of polarized and non-polarized photos among different groups.

Abbreviations: GD, general dentist; Ortho, orthodontist; GMR, Gingival Melanosis Record.

Figure 9 Percentage of DOPI reduction of polarized and non-polarized photos among different groups.

Abbreviations: GD, general dentist; Ortho, orthodontist; DOPI, Dummett Oral Pigmentation Index.