ion regarding the chemical elements present in the specimen from Group 2 shows a statistically significant difference (p <0.05) in the experimental faces when comparing to the positive control faces for carbon, calcium, nitrogen, phosphorus and strontium. These 
D1 (Colgate Sensitive Pro-Relief®), dentifrice D3 (Sensodyne Repair & Protect®)
D2 (Sensodyne Rapid Relief®), D4 (Colgate Maximum Cavity Protection®)
colloidal stability