Mode of action studies on the formation of enamel minerals from a novel toothpaste containing calcium silicate and sodium phosphate salts.
OBJECTIVES
To investigate in vitro and in situ the deposition and formation of hydroxyapatite (HAP) on enamel surfaces following brushing with a novel toothpaste containing calcium silicate (CaSi), sodium phosphate salts and fluoride.


METHODS
Polished enamel blocks were brushed in vitro with a slurry of the CaSi toothpaste. After one brush and four weeks simulated brushing the enamel surfaces were analysed. In an in situ protocol, enamel blocks were attached to first or second molar teeth of healthy subjects, exposed to 4 weeks twice per day brushing with the CaSi toothpaste and then analysed. The surface deposits were analysed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). In addition, the CaSi toothpaste was slurried in simulated oral fluid (SOF) over a 3 hour period and the solids were isolated and analysed by Fourier transform infrared spectroscopy (FTIR).


RESULTS
The FTIR study demonstrated that calcium phosphate phases had formed and these became increasingly crystalline over 3 hours. CaSi was deposited onto enamel surfaces following one brushing with the toothpaste in vitro.The deposited particles showed evidence of HAP crystalline phases associated with the CaSi. Following 4 weeks brushing in vitro, the deposition increased and analyses showed that the deposited material was HAP. These results were confirmed by the in situ study.


CONCLUSIONS
Calcium silicate can be deposited onto enamel surfaces from a novel toothpaste formulation where it can form the enamel mineral HAP.


CLINICAL SIGNIFICANCE
A novel toothpaste formulation containing CaSi can form HAP on enamel surfaces. The potential of this technology is for a novel approach to the repair of demineralised enamel and the protection of enamel during acid exposure.
['Sun|Yuekui|Y|', 'Li|Xiaoke|X|', 'Deng|Yan|Y|', 'Sun|Jianing N|JN|', 'Tao|DanYing|D|', 'Chen|Hui|H|', 'Hu|Qinghong|Q|', 'Liu|Renjiang|R|', 'Liu|Weining|W|', 'Feng|Xiping|X|', 'Wang|Jinfang|J|', 'Carvell|Mel|M|', 'Joiner|Andrew|A|']
D000818:Animals D002118:Calcium D017610:Calcium Compounds D002130:Calcium Phosphates D002417:Cattle D003461:Crystallography D003743:Dental Enamel D044622:Dental Pellicle D017886:Durapatite D005459:Fluorides D005500:Follow-Up Studies D006801:Humans D066298:In Vitro Techniques D008422:Materials Testing D008855:Microscopy, Electron, Scanning D046529:Microscopy, Electron, Transmission D010710:Phosphates D011897:Random Allocation D012464:Saliva, Artificial D017640:Silicates D013052:Spectrometry, X-Ray Emission D017550:Spectroscopy, Fourier Transform Infrared D013997:Time Factors D014099:Toothbrushing D014100:Toothpastes
Enamel Toothpaste Calcium silicate Hydroxyapatite Erosion Mineralisation