Caries means demineralization with the formation of cavities and pulp symptoms and necrosis as an end result. The acids in the mouth are mainly produced by oral bacteria like Streptococcus mutans from bacterial biofilms adhering to the tooth. Ozone has been shown to have a very strong bactericidal effect on bacteria causing dental caries (Baysan et al., 2001). Baysan et al. (2000) reported that there was a statistically significant reduction of streptococci in root caries lesions and saliva samples after ozone application. The positive clinical effect of ozone with respect to arresting caries progression and the remineralization of caries has been shown in vitro and in vivo. In an in vivo study, Baysan and Lynch (2001) found that the application of ozone resulted in a significant reduction of bacterial contamination as well as a reduction in size and severity of root caries lesions. In a subsequent study, Baysan and Lynch (2002) reported that the severity of root caries lesions was significantly reduced after ozone application as measured by electrical conductance and laser fluorescence. In several studies, the caries reducing effect of ozone was measured with biochemical methods in root surface caries lesions, the biofilm and saliva after ozone application (Lynch et al., 2001; Silwood et al., 2001; Mills et al., 2001; Claxon et al., 2002; Lynch et al., 2002).

The objectives of this multi-center clinical study are to determine: (1) the effectiveness of the HealOzone in stopping the progression of fissure caries; and (2) the oral soft tissue safety of the ozone system.

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.

Inclusion Criteria:

To be eligible for study participation, subjects must:

1. provide written informed consent, HIPAA authorization and medical history information prior to their participation; 2. be between the ages of 10 and 40 years of age; 3. if female and of childbearing potential, must agree to:

• a urine pregnancy test, which must be negative;
• to use one form of medically accepted contraceptive measures which include oral contraceptives, condom, or diaphragm with spermicide, Intra Uterine Device (IUD), Depo-Provera, Norplant during the study and for at least 30 days after the last treatment. (Females who are post menopausal, i.e. amenorrhea for the previous 12 months, or surgically sterile may be included.) 4. be in good general health as evidenced by a review of the medical history; 5. have good oral health; 6. agree to comply with all subjects' responsibilities as stated in the protocol (e.g. attendance at appointments, turning off of cell phone during appointment, etc.); and 7. have two posterior (molar or premolar) teeth with active fissure caries as defined by ICDAS severity score between 1 and 4, a caries lesion activity score of 2, and with radiographic evidence indicating that there is no extension past the dentinal enamel junction. Lesions within the same subject ideally should have the same ICDAS criterion; however, the following deviations will be acceptable - teeth with ICDAS criterion 1 paired with a 2, and a 3 paired with a 4.

Exclusion Criteria:

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• Tufts University
• SUNY School of Dental Medicine