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Quantification of white spot lesions around orthodontic brackets with image analysis.

OBJECTIVE
To investigate the use of image analysis for diagnosis and quantification of artificial white spot lesions on digital photographs before and after removal of orthodontic brackets.


MATERIALS AND METHODS
Enamel demineralization was artificially induced on the labial surface of 20 teeth bonded with orthodontic brackets. Standardized digital photographs were taken at angles of 90 degrees and 110 degrees to the labial surface, before and after bracket removal. All images were analyzed by two observers using image-processing software, and the area of the white spot lesion was calculated. Reproducibility was assessed by the Pearson correlation coefficient for interobserver reliability and by the paired t-test for differences between observers. Differences between the known and the measured demineralization area were tested using the t-test. Differences between both stages and angles were assessed by application of the paired t-test.


RESULTS
Reproducibility was very good for all measurements. For the photographs taken at an angle of 110 degrees , there was a statistically significant but clinically irrelevant difference between the observers. The difference between the surface measured and the true surface was dependent on the stages and angles but was always <1 mm2.


CONCLUSION
Image analysis is a reproducible and reliable method for quantification of artificial enamel demineralization around orthodontic brackets.