IADR Abstract Archives
The Use of Microhardness and Transverse Microradiography to Assess Remineralization
Objectives: To compare the use of transverse microradiography (TMR), percent surface microhardness recovery (%SMHR) and cross-sectional microhardness (CSMH) for measurement of enamel subsurface lesion remineralization in vitro by commercially available tooth crèmes and toothpastes.
Methods: Extracted human molars with artificial subsurface lesions were exposed to one of six solutions (n = 7): (1) Artificial saliva (AS – 0.5mM CaCl2, 0.5mM Na2HPO4, 50mM NaCl, 20mM HEPES, pH 7.0), (2) AS with 1000 ppm F- toothpaste, (3) AS with Tooth Mousse (10% CPP-ACP), (4) AS with Tooth Mousse Plus (10% CPP-ACP + 900 ppm F-), (5) AS with Apagard toothpaste (nano-hydroxyapatite), (6) AS with Remin Pro (nano-hydroxyapatite + 1450 ppm F-). Dilutions of fluoride-containing products equated fluoride concentration to 100 ppm F-. All enamel blocks were analysed with TMR and %SMHR, and three random blocks from each group using CSMH. Data were assessed using a one-way ANOVA with Tukey post hoc multiple comparison tests, and correlations using Pearson’s correlation.
Results: Percent remineralization measured by TMR was: 4 (31.5±3.3%) > 3 (24.9±1.4%) > 2 (15.6±1.8%) = 5 (16.1±1.8%) = 6 (16.7±2.5%) > 1 (12.6±0.9%). %SMHR for groups 1-6 was 3.9±1.4, 8.6±1.9, 8.9±2.3, 7.4±1.5, 14.4±2.2, and 4.6±1.9 respectively. Percent remineralization measured by CSMH was: 4 (37.1±4.4%) = 3 (34.5±6.5%) > 2 (18.4±2.6%) = 5 (11.3±1.1%) = 6 (11.7±1.7%) = 1 (12.2±2.6%). There was poor correlation between TMR and %SMHR measurements (r = 0.11, p > 0.05) and between CSMH and %SMHR measurements (r = 0, p > 0.05), while there was good correlation between TMR and CSMH measurements (r = 0.84, p < 0.001).
Conclusions: For measurement of enamel remineralization, TMR and CSMH were suitable methods for analysis of subsurface mineral change. TMR was the most appropriate method to differentiate between groups. %SMHR correlated poorly with TMR and CSMH and was unsuitable to assess remineralization.
Methods: Extracted human molars with artificial subsurface lesions were exposed to one of six solutions (n = 7): (1) Artificial saliva (AS – 0.5mM CaCl2, 0.5mM Na2HPO4, 50mM NaCl, 20mM HEPES, pH 7.0), (2) AS with 1000 ppm F- toothpaste, (3) AS with Tooth Mousse (10% CPP-ACP), (4) AS with Tooth Mousse Plus (10% CPP-ACP + 900 ppm F-), (5) AS with Apagard toothpaste (nano-hydroxyapatite), (6) AS with Remin Pro (nano-hydroxyapatite + 1450 ppm F-). Dilutions of fluoride-containing products equated fluoride concentration to 100 ppm F-. All enamel blocks were analysed with TMR and %SMHR, and three random blocks from each group using CSMH. Data were assessed using a one-way ANOVA with Tukey post hoc multiple comparison tests, and correlations using Pearson’s correlation.
Results: Percent remineralization measured by TMR was: 4 (31.5±3.3%) > 3 (24.9±1.4%) > 2 (15.6±1.8%) = 5 (16.1±1.8%) = 6 (16.7±2.5%) > 1 (12.6±0.9%). %SMHR for groups 1-6 was 3.9±1.4, 8.6±1.9, 8.9±2.3, 7.4±1.5, 14.4±2.2, and 4.6±1.9 respectively. Percent remineralization measured by CSMH was: 4 (37.1±4.4%) = 3 (34.5±6.5%) > 2 (18.4±2.6%) = 5 (11.3±1.1%) = 6 (11.7±1.7%) = 1 (12.2±2.6%). There was poor correlation between TMR and %SMHR measurements (r = 0.11, p > 0.05) and between CSMH and %SMHR measurements (r = 0, p > 0.05), while there was good correlation between TMR and CSMH measurements (r = 0.84, p < 0.001).
Conclusions: For measurement of enamel remineralization, TMR and CSMH were suitable methods for analysis of subsurface mineral change. TMR was the most appropriate method to differentiate between groups. %SMHR correlated poorly with TMR and CSMH and was unsuitable to assess remineralization.