• Primary efficacy measurement will be the ICDAS severity value [ Time Frame: one year ] [ Designated as safety issue: No ]
  

• Secondary efficacy parameters will be measured by caries lesion activity score, radiographic changes, and Diagnodent measurements. [ Time Frame: one year ] [ Designated as safety issue: No ]
  

The proposed study is designed as a twelve-month, multi-center, double-blind, randomized controlled clinical study involving approximately 402 subjects with 804 lesions. There are three sites participating in this trial: Indiana University School of Dentistry (lead site), Tufts University School of Dental Medicine, and SUNY School of Dental Medicine. Each site will submit a version of the protocol to their respective Institutional Review Board ("IRB") that incorporates the specific institutional and state guidelines and regulations applicable to that site.

The two treatment regimens will be: (a) placebo treatment and (b) experimental ozone treatment. Selected subjects must have at least two teeth with similar stages of early active fissure caries. The selection of the study teeth will be determined by a review of the visual examination, including the ICDAS severity score and the caries lesion activity score, conducted at the screening visit, in conjunction with the bitewing radiographs. The decision whether a tooth will be treated with ozone or receive placebo treatment will be made randomly.

All clinical personnel involved in the clinical examinations and treatment application will be trained at the primary site prior to the initiation of the trial both in the use of the device, and in how to identify the signs and symptoms of ozone toxicity and in how to provide the appropriate medical response should any of these signs or symptoms be observed.

All qualified subjects will receive the following:

1. Professional dental cleaning and scaling at the Screening Visit (or separate visit prior to baseline visit and after completing the study at 12 months.

2. Diagnostic procedures:

   1. Clinical visual examination (utilizing ICDAS severity scoring)
   2. Clinical visual/tactile assessment of caries lesion activity
   3. Bitewing x-rays
   4. Laser fluorescence measurement (utilizing the DIAGNOdent, KaVo)
3. Treatment Regimen:

The assigned investigational treatment regimen will be administered on the two selected study teeth at the baseline, and at the three-, six- and nine-month appointments. After three, six, nine and twelve months, the diagnostic procedures will be repeated with the exception of bitewing x-rays, which will only be repeated at the twelve-month exam (unless the examining dentist determines that x-rays also are needed at the six- or nine-month visit to confirm whether dentinal caries is present). In addition, a digital photograph may be taken of selected study teeth to document clinical changes over the study period.

If a selected study tooth progresses from an initial caries lesion to a more advanced lesion, which in the judgment of the examining dentist requires restorative intervention, the tooth will be restored at no cost to the subject and the lesion will be recorded as 'progression from baseline' at any remaining examinations. The subject will be eligible to remain in the study. Subjects will receive a thorough dental cleaning and scaling and topical fluoride treatment at the conclusion of the twelve-month examination.