The effect of Simulated Dentinal Fluid following six week remineralization

Introduction: Previously, calcium levels in test samples were shown to be greater than controls after three weeks of remineralization (Vu 2006). Variation in calcium profiles with different levels of demineralization suggested a need to investigate the effect of longer exposure to remineralization. Objective: To study the relationship between exposure time to simulated dentinal fluid (SDTF) and calcium uptake by demineralized dentine. Materials and methods: Standard cavities were cut in six extracted, intact third molar teeth. These teeth were exposed to demineralizing solution for generation of artificial caries. Half of the demineralized cavity floor was protected with nail varnish (control side). The remaining half was in contact with Fuji IX (test side). A reservoir was connected to each pulp chamber to supply SDTF under recognized hydrostatic pressure for six weeks during which ion-exchange was proceeding between GIC and demineralized dentine. Afterwards, teeth were prepared for Electron Probe Analysis to determine profiles of Ca, P, F and Sr. Results: Generally, calcium levels on the test sides were greater than those of the control sides (significant, p=0.02). Strontium and phosphorus increased on the test side compared to the control sides (significant, p=0.02 and p=0.01 respectively). Mean of calcium of the control sides at three week remineralization (8678.8) were greater than those at 6 week remineralization (6802.9) (p=0.004). Mean of calcium of the test sides at three week remineralization was also greater than that at six week remineralization but not significantly (p=0.33). Discussion: Increased calcium, phosphorus and strontium levels of the test sides versa control sides demonstrated the continuing contribution of SDTF to remineralization which agreed with previous results. However, the decreased calcium at six week remineralization on both test and control sides suggested a need for further investigation. Conclusion: There was no evidence of greater remineralization at longer exposure time using this model.