Computer-based thermal imaging of human gingiva: preliminary investigation

Computer-based thermal imaging techniques were used to compare the rewarming rates of normal and inflamed human gingiva following cooling. A Modified Gingival Index (MGI) score, gingival crevicular fluid (GCF) measurement, and clinical photograph were obtained from a maxillary or mandibular anterior facial region in 20 subjects, aged 25 to 44. Baseline thermograms of the marginal/papillary (M/P) and adjacent attached gingiva (AG) were recorded following an acclimatization period with the patient seated and chin resting on a positioning apparatus. The tissue was then cooled with a gentle stream of air and thermograms were recorded at 10 second intervals for 3 minutes as the tissue rewarmed. Rewarming slopes were calculated based on these thermograms. Correlation coefficients were calculated for MGI with GCF, as well as for both MGI and GCF with AG and M/P rewarming slopes. Mean baseline (SE) temperatures (degrees F) for AG were 75.9 (0.9), 78.0 (0.6), and 80.3 (1.3) for normal, mildly inflamed, and moderately-severely inflamed gingivae, respectively; corresponding mean (SE) temperature differences (degrees F) between AG and M/P were 0.5 (0.2), 0.9 (0.2), and 1.4 (0.3). Intragroup mean M/P temperatures were less than mean AG temperatures, with the mean regional differences increasing with greater severity of inflammation. Rewarming rates also increased as inflammation became more severe, with the rewarming slopes of both the AG and M/P having statistically significant correlations with the MGI and the GCF. The correlation between MGI and GCF was also statistically significant. This study suggests that computer-based thermal imaging techniques can detect both static and dynamic temperature differences between normal gingiva and gingivae with increasing severities of inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)