The purpose of the clinical study is to evaluate the safety and bacterial impact of study drug (C16G2) administered in multiple oral gel doses to adolescent and adult dental subjects.

The purpose of the clinical study is to evaluate the safety and microbiology of C16G2 administered in multiple oral gel doses to adolescent and adult dental subjects. Subjects will be assigned to three study cohorts and receive 2 different volumes of C16G2 Gel or Placebo. Prior to commencing enrollment of subjects 12-17 years of age, a safety only cohort of 4-8 adolescent subjects will receive 4 study drug administrations on Day 0. A safety data review will be performed by the Medical Monitor on Days 1 and 5. If no safety concerns are identified, enrollment of adolescent subjects receiving 7 days of study drug administration will be initiated in Study Arms 1 & 2. Enrollment of adult subjects in Study Arms 1 & 2 may start before the Adolescent Safety Only Cohort is initiated. Before dosing of study drug, eligible subjects will undergo professional dental prophylaxis on Day 0. Microbiology will be assessed by measuring S. mutans and total bacteria counts.

Inclusion Criteria:

1. Adolescent Safety Only Cohort: Males and females, 12-17 years of age, inclusive, at the time the Assent and Informed Consent Form is signed. Study Arms 1 & 2: Males and females, 12-75 years of age, inclusive, at the time the Assent and/or Informed Consent Form is signed
2. 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, relationship with same sex partner or partner who has had a vasectomy at least six (6) months prior to the screening visit
3. 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
4. Healthy, as determined by the Investigator, based on medical and dental history, concurrent illnesses, laboratory results, concomitant medications, oral cavity assessment, and targeted physical examination (extraoral, head and neck) during Screening
5. Have a minimum of six unrestored bicuspids and molars with ≤50% of molars and bicuspids having restorations, crowns, sealants or are missing
6. Demonstrated ability to expectorate ≥2mL of stimulated saliva in 5 minutes
7. Have a salivary S. mutans of 1.0 x 10e5 CFUs/mL or greater at Screening using MSB agar plating
8. Willing to refrain from using non-study dentifrice and other non-study oral care products (oral care rinses, fluoride products, etc.) during the study
9. Willing to postpone elective dental procedures (e.g., dental cleanings) between Screening and final post-treatment visit
10. Willing and able to comply with oral hygiene and diet instructions
11. Has dentition adequate for custom dental tray gel application
12. Able to understand and sign the Assent and/or Informed Consent Form prior to initiation of study procedures
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); Note: Subjects presenting with insipient, non-cavitated lesion(s) are not excluded
3. 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
4. Pathologic lesions of the oral cavity
5. Full or partial dentures, or orthodontic appliances, e.g., night guards, permanent retainers
6. 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
7. Medical history indicating the woman is pregnant, breastfeeding/ lactating or has a positive urine pregnancy test
8. Participation in a clinical trial or receipt of a non-FDA approved therapy within 30 days prior to study drug administration
9. Prior participation in a C16G2 clinical trial and known to have received C16G2 active gel or mouth rinse
10. Presence of any condition or concurrent illness, which in the opinion of the Investigator, would compromise normal immune function, 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