Lithothamnion Calcareum Potentiates the in-Vitro Bioactivity of Enamel-Based Biomaterials

Objectives: We developed biomaterials derived from dental enamel which are primary envisioned to assist the remineralization of caries- and/or erosion-affected teeth. This study assessed the effects of Lithothamnion Calcareum (LC) addition on the in-vitro bioactivity of these novel biomaterials. Since LC solution demonstrated in tandem ability to prevent demineralization and promote remineralization of pH-challenged enamel, we hypothesized LC could potentiate the bioactivity of developed biomaterials.
Methods: Enamel powder was obtained from 10 de-identified caries-free extracted teeth, washed, air-dried, separated into 2-equal aliquots (3g/each) and partially demineralized overnight with either lactic (pH4.2) or citric acid (pH3.3). Lactic- and Citric-acid-demineralized enamel were mixed with either 0% or 5% LC powder. Samples were suspended in either 1% chitosan or 1% gelatin. Chitosan and gelatin solutions were used as vehicles to produce injectable materials. Disc-like constructs (1x4mm diameter) were obtained by injection of each material into custom-made molds. Constructs were stored either in dry conditions, water or simulated-body-fluid (SBF) for 4 days (n=3/biomaterial/storage-condition). Specimens were analyzed using Spectrum-Two ATR-FTIR instrument (PerkinElmer). Shifts in spectral peaks corresponding to apatite mineral were compared among samples and against pristine materials. Data were analyzed by inferential statistics.
Results: Increased absorbance of apatite IR-peaks (~564 and 1000cm^-1), suggesting increased in-vitro bioactivity, were seen for SBF-stored lactic- and citric-acid-demineralized-enamel biomaterials added with LC. The most notable increasing/shifts of apatite IR-peaks were seen for lactic- and citric-demineralized-enamel-based biomaterials suspended in chitosan. Enamel-based biomaterials suspended in gelatin resulted into crumble-like, hard-to-manage constructs. No significant increasing/shift of apatite IR-peaks was observed for dried- or water-stored samples.
Conclusions: LC potentiated the in-vitro bioactivity of novel enamel-based biomaterials. Experiments that aim at measuring the synergistic effect of these biomaterials and LC on the prevention of enamel demineralization and promotion of enamel remineralization are currently undertaken.