The aims of this study were to determine the sucrose and liquid oral pediatric medicines of long-term effect on dental biofilm pH to evaluate the cariogenic potential in vivo.

Te study was carried out with 12 subjects that were refrained from brushing their teeth for 28 h and did not eat or drink for at least 3 h prior to each appointment. Dental biofilm pH was measured in the cervical and proximal regions of anterior teeth with beetrode-type microelectrode coupled to a potentiometer. The biofilm was submitted nine paediatric medicines a long term and sucrose (negative control). pH measurements were taken at baseline to determine resting plaque pH and at time interval 5, 10, 15, 20, 25 and 30 minutes.

Inclusion Criteria:

• Age 18 to 22 years;
• Having Oral hygiene adequate (OHI<1.1);
• Having 20 natural teeth incluing molar;
• Not havind oral disease.

Exclusion Criteria:

• Biofilm baseline pH > 5,5;
• Not signature consent term;
• Using orthodontic appliance;
• Having used medicines last 3 months;
• Pregant woman.