Preservation of Organic Matrix Increases Recovery of Eroded Dentin Specimens

Objectives: The aim of this study was to evaluate if the preservation of the demineralized organic matrix (DOM) on eroded dentin blocks influences the degree of tissue recovery during immersion in remineralizing solution.
Methods: Twenty-four human root dentin blocks (4x4x2mm) were demineralized by immersion in 1% citric acid solution (pH 2.3) for 60min (20 mL/specimen). After demineralization, tissue loss was evaluated by profilometry. In G1 (n=8) the DOM was removed by immersion in 0.5 mL of mineral solution containing type VII collagenase from Clostridium histolyticum (100U/mL) for 96h. Specimens from G2 and G3 had the DOM preserved and received application (1min) of placebo gel or gel containing 10mM chlorhexidine, respectively. Then all the specimens were immersed in remineralizing solution (1.45mM CaCl₂, 5.4mM K₂HPO₄, 0.05mM ZnCl₂, 100mM TRIS, pH 7.0) for 14 days (20 mL/specimen). Profilometry was performed again after days 7 and 14. Data were analyzed by 2-way repeated-measures ANOVA and Tukey´s test (p<0.05).
Results: Mean (±SD, µm) tissue loss after initial demineralization was: G1-28.7±1.2, G2-26.5±1.3 and G3-25.6±1.1. After 7-day remineralization, tissue loss was significantly lower than initial values for G2 and G3 (G1-27.8±1.1, G2-22.3±0.9 and G3-21.1±0.4), while after 14 days all groups presented significant lower tissue loss in respect to initial loss. Additionally, G2 and G3 also had tissue losses significantly lower than those observed after 7 days (G1-27.0±1.1, G2-18.9±2.1, G3-18.4±0.3). Regardless the time of evaluation, the groups where the DOM was preserved (G2 and G3) had similar tissue losses, but these were significantly lower than those found for G1.
Conclusions: The preservation of the DOM increases the degree of tissue recovery during immersion in remineralizing solution but the treatment with chlorhexidine gel had no significant effect on this process. Financial support: CNPq 401347/2012-5.