To determine the effect of an amino acid on bacterial glycolytic acid formation in human interdental plaque.

Inclusion Criteria:

• Maxillary dentition is preferentially natural.
• Maxillary restorations and/or reconstructions and eventual partial dentures must be in clinically good condition.
• Natural mandibular front teeth and first premolars (4-4) are retained.
• Second mandibular molars are ideally present to serve as abutment teeth.
• Mandibular restorations and/or reconstructions must be in clinically good condition.
• Partial mandibular denture replacing second premolars and first (and second) molars in good clinical condition.
• Subjects should have a stimulated saliva flow rate of 1-2 ml/min (by chewing paraffin wax).
• Willingness to give their informed consent and comply with the protocol.
• No history of allergy to personal/oral care consumer products or ingredients, relevant to any ingredient in the test products as determined by the dental/medical professional monitoring the study

Exclusion Criteria:

• Current participation in other dental clinical trials.
• Subjects who are unable to provide sufficient plaque growth over a 2-day non- brushing period (by visual assessment).
• Subjects in whom the plaque pH fails to fall sufficiently, i.e. at least to pH 5 following a sucrose rinse.
• Subjects with poor oral health, i.e. with advanced periodontitis, un-restored carious lesions and stomatological diseases.
• Subjects taking drugs known to currently affect salivary flow.
• Subjects with un-stimulated salivary flow <0.3 ml/min and/or stimulated flow <0.9 ml/min.
• Women who are pregnant or breastfeeding
• History of allergy to common dentifrice ingredients
• Immune compromised individuals (HIV, AIDS, immuno suppressive drug therapy)
• Women of child bearing potential and not on birth control (Diaphragm, birth control pills or implants, IUD (intrauterine device) or condoms)
• Medical condition which requires premedication prior to dental procedures/visits
• History of allergy to amino acids

6 weeks