Phase 2, Safety & Microbiology Study of C16G2 in Multiple Oral Gel &/or Mouth Rinse Doses to Healthy Adults

The focus of the study is to evaluate the safety of multiple study drug administrations and the study drug selectively reducing or eliminating a specific bacteria in the mouth. It will compare a liquid and gel product applied in different modes.

The study will evaluate the safety of multiple study drug administrations as assessed by adverse event monitoring, oral cavity assessments, targeted physical exams and vital signs. The study will also assess the study drug's ability to selectively reduce or eliminate specific bacteria in the mouth by comparing a liquid and gel product applied in different modes, such as mouth rinse administration and gel application using a dental tray, electric toothbrush or manual toothbrush administered over 7 consecutive days. Subjects will be followed for approximately 8 days after the last study drug administration for safety and microbiology.

Eligibility Criteria:
Inclusion Criteria:

Subjects are eligible to participate if they meet the following criteria:

* Males and females, 18-75 years of age, inclusive, at the time the Informed Consent Form is signed
* Female subjects of childbearing potential, defined as not surgically sterile or at least two (2) years postmenopausal, 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, monogamous relationship with same sex partner or partner who has had a vasectomy at least six (6) months prior to the screening visit.
* Male subjects only: 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.
* Healthy, as determined by the Investigator (in consultation with the Medical Monitor, as needed), based on medical and dental history, laboratory results, concomitant medications, oral cavity assessment, and targeted physical examination (extraoral, head and neck) during Screening
* Have a minimum of six unrestored bicuspids and molars with less than 50% of molars and bicuspids having restorations, crowns, sealants or are missing
* Demonstrated ability to expectorate ≥2 mL of stimulated saliva in 5 minutes
* Demonstrated ability to swish 10 mL of water for 4 minutes
* Have a salivary and dental plaque S. mutans of 2.0 x 10\^4 colony forming unit (CFU)s/mL or greater at Screening using mitis salivarius-bacitracin (MSB) agar plating
* Willing to refrain from using non-study dentifrice and other non-study oral care products during the study
* Willing to postpone elective dental procedures (e.g. dental cleanings) between Screening and final post-treatment visit (End of Study or Early Termination)
* Able to understand and sign the Informed Consent Form prior to initiation of study procedures
* Able to communicate with the Investigator/study site personnel, understand and comply with the study requirements, and willing to return for protocol-specified visits at the appointed times

Exclusion Criteria:

Subjects are excluded from participation if any of the following apply:

* Advanced periodontal disease
* Active caries lesion(s) within 30 days prior to study drug administration (confirmed by dental examination and standard radiographs).
* 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
* Pathologic lesions of the oral cavity (suspicious or confirmed)
* Full or partial dentures, or orthodontic appliances, e.g. night guards, permanent retainers
* Impaired salivary function (unable to provide 2 mL of stimulated saliva within 5 minutes)
* Use of systemic antibiotics, topical oral antibiotics, or use of other drugs, which in the opinion of the Investigator could influence the study outcome, within 30 days prior to Screening
* Medical history indicating the woman is pregnant, breastfeeding/lactating or she has a positive urine pregnancy test
* 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)
* 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