The objective of this study is to evaluate how well the study product, Crest Daily Whitening Serum, alleviates Xerostomia and perceived halitosis over 1 week of use.

Inclusion Criteria:

• At least 18 years of age.

• Can produce an unstimulated salivary flow rate of 0.18mL/min. or less.

• Score of 3 or more on question 1 of the VAS dry mouth scale (How severe is your dryness right now?), evaluated in the Pre-Product Use Dry Mouth & Sensitivity Questionnaire.

• Evidence of currently taking a stable dose (3 months or more) of Xerostomia-inducing medication such as, antihypertensives, anti-anxiety agents, psychiatric remedies, antihistamines and etc.

  • At screening, participants may present the prescription bottle, a picture of the prescriptions bottle or medical records showing the prescription.

• Subject not currently using any teeth whitening or desensitizing products that contain potassium nitrate such as Sensodyne, Pronamel etc.

• Subject willing to comply with the study regimen and products.

  • Not consume alcohol for 24 hours prior to their visit.
  • Not brush their teeth for 1.5 hours prior to their visit.
  • Not have had anything to eat or drink (including chewing gum or eating candy) for 1.5 hours prior to their visit). Water is acceptable to drink up to 1 hour prior to the study visit.
  • Not smoke 1.5 hours prior to their visit

Exclusion Criteria:

i. Subjects who are currently pregnant (self-reported). ii. Unstimulated salivary flow rate of more than 0.18mL/min iii. Subjects that have ever received therapeutic radiation in the head and neck area.

iv. Subjects with a diagnosis of conditions that would affect salivary flow such as Sjogren's Syndrome per the investigator's expert opinion.

v. Subjects with a condition the investigator believes not suitable for the study, such as autoimmune diseases and radiation therapy to head and neck region that impact salivary flow.

vi. Subjects that currently use whitening toothpaste, desensitizing toothpaste, or any other products causing similar results.

vii. Subjects currently participating in any other research studies. viii. Subject unable to provide consent (e.g. Cognitively impaired adults). ix. Non-English speaking