The purpose of this single-blind study is to evaluate whether C16G2 Varnish administered in multiple doses can effectively kill the bacteria in the oral cavity that cause dental caries.

A single-blind, randomized, placebo-controlled Phase 2 study to evaluate the safety and oral microbiology of C16G2 Varnish application in male and female dental subjects 12-75 years of age. This multi-center study will evaluate multiple study drug administrations of C16G2 Varnish or Placebo Varnish.

The study will enroll subjects into up to three study arms. Up to 33 subjects will receive multiple doses of study drug applied with a small brush typically used in dental varnish administration. Subjects will be enrolled in an 8:3 ratio. The Sponsor will perform unblinded microbiology review on an ongoing basis to determine whether to enroll additional 11 subjects into the next dose cohort or to terminate enrollment based on microbiology data.

Inclusion Criteria:

1. Males and females, 12-75 years of age

2. Adults subjects provide written informed consent and adolescent subjects give written or verbal assent, as appropriate, and parent(s) or legal guardian(s) give written informed consent

3. Female subjects of childbearing potential must agree to use one of the following forms of contraception from screening through the last study visit: hormonal (oral, implant, or injection) begun >30 days prior to screening; barrier (condom, diaphragm, or cervical cap with spermicide); intrauterine device (IUD). Acceptable contraceptive options may also include abstinence, relationship with a same sex partner or partner who has had a vasectomy at least six (6) months prior to the screening visit

4. Negative urine pregnancy test in all females of childbearing potential (past menarche)

5. Male subjects of sexual activity age: willing to use contraception or abstain from sexual activity beginning with the first exposure to study drug and continuing until discharged from the study due to completion or Early Termination

6. Healthy, as determined by the Investigator (in consultation with the Medical Monitor, as needed), based on medical and dental history, concurrent illnesses, laboratory results, concomitant medications, oral cavity assessment, and targeted physical examination (general, extraoral, head and neck) during Screening.

   Note: Subjects on a stable dose of medication may be eligible for screening and will be assessed by the medical monitor on a case-by-case basis.

7. Have a minimum of 12 bicuspids and molars with a minimum of 8 molars and bicuspids NOT having restorations, crowns or sealants

8. Demonstrated ability to expectorate ≥2 mL of stimulated saliva in 5 minutes

9. Have a salivary S. mutans of 1.0 x 10^5 CFUs/mL or greater at Screening using mitis salivarius-bacitracin (MSB) agar plating

10. Willing to refrain from using non-study dentifrice and other non-study oral care products (oral care rinses, fluoride products, etc.) during the study

11. Willing to postpone elective dental procedures (e.g., dental cleanings) between Screening and final post-treatment visit (End of Study or Early Termination)

12. Willing and able to comply with oral hygiene and diet instructions

13. Able to communicate with the Investigator/study center personnel, understand and comply with the study requirements, and willing to return for protocol-specified visits at the appointed times

Exclusion Criteria:

1. Advanced periodontal disease

2. Active caries lesion(s) within 30 days prior to study drug administration (confirmed by comprehensive caries examination including standard radiographs). Subjects presenting with insipient, non-cavitated lesion(s) are not excluded.

   Note: If radiographs are deemed appropriate for the study and taken within 6 months prior to the Screening visit, these may be used for determining eligibility and not required to be repeated at Screening

3. Partially erupted teeth where the entire crown is not erupted or an operculum is present

4. Medical condition (e.g., artificial heart valve, history of infective endocarditis, cardiac transplant with valvular dysfunction, congenital heart disease or total joint replacement) for which antibiotics are recommended prior to dental visits and/or procedures

5. Pathologic lesions of the oral cavity (suspicious or confirmed)

6. Full dentures or permanent orthodontic appliances, e.g., braces, buccal or lingual brackets. Note: Partial dentures, removable retainers and night guards are not excluded, provided that they are cleaned regularly throughout the duration of the study

7. Use of systemic antibiotics, topical oral antibiotics, or use of other drugs, which in the opinion of the Investigator could influence the study outcome, beginning 30 days prior to Screening until the end of study participation

8. Medical history indicating the woman is pregnant, breastfeeding/lactating or has a positive urine pregnancy test

9. Participation in a clinical trial or receipt of a non-FDA approved therapy within 30 days prior to study drug administration (depending on the specifics, participation in an observational study is not necessarily excluded)

10. Presence of any condition or concurrent illness, which in the opinion of the Investigator, would compromise normal immune function (e.g., diabetes, rheumatoid arthritis, lupus, liver disease, organ transplant, etc.), interfere with the use of study dentifrice and oral care products, or interfere with the ability to comply with study requirements, or jeopardize the safety of the subject or the validity of the study results

2 months