African Journal of Dentistry

African Journal of Dentistry ISSN 2756-3421 Vol. 13 (1), pp. 001-012, January, 2025. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Evaluating the Efficacy of NaF and Tricalcium Phosphate Toothpastes on White-Spot Lesions Using Synchrotron Radiation Micro-CT

Makoto Asaizumi1*, Kentaro Uesugi2, Masato Hoshino2, Tomoaki Kato3, Allen C. Mackey4 and Robert L. Karlinsey5

1Dr. Makoto Asaizumi Orthodontic Practice, Ban Bldg., 3F., 1-8 Chiyodacho, Mobara, Chiba 297-0023, Japan.
2SPring-8/JASRI, 1-1-1 Kouto, Sayocho, Sayogun, Hyogo 679-5198, Japan.
3Dr. Tetsuya Kuga Dental Practice, 924 Kamiichiba, Mutsuzawamachi, Chouseigun, Chiba 299-4403, Japan.
4University of Michigan, 2122 Lurie Biomedical Engineering, 1101 Beal Avenue Ann Arbor, MI 48109-2110, USA.
5Indiana Nanotech, 14 East Washington Street, Suite 6A, Indianapolis, IN 46204, USA.

Accepted 22 November, 2024

Synchrotron radiation micro-computed tomography (SR micro-CT), considered superior to standard polychromatic micro-CT techniques, was used to assess the densities of bovine enamel white-spot lesions (WSL) treated in a 10-day pH cycling model with either: (A) Clinpro Tooth Crème (0.21% NaF plus TCP), (B) Clinpro 5000 (1.1% NaF plus TCP) or (C) Tom’s of Maine (0% NaF) dentifrice. Each day consisted of four 2 min treatments, one 4 h acid challenge (pH=5.0), and immersion in artificial saliva (pH=7.0) between these events. After 10 days, WSL specimens were evaluated for lesion depth using confocal microscopy and lesion density using SR micro-CT with depths ranging from 2.76 to 113.16 μm, in 2.76 μm slice increments. Statistical analyses (Student’s t-test) were performed at the 95% confidence level. SR micro-CT analyses revealed the NaF plus TCP dentifrices improved WSL densities relative to the fluoride-free toothpaste, and is consistent with an earlier study utilizing polychromatic micro-CT. In contrast to previous findings, SR micro-CT analyses also revealed significant differences in WSL densities treated with the two NaF dentifrices at enamel depths of 13.80, 16.56, and 19.32 μm. These findings suggest SR micro-CT may be especially suited for detecting density differences in lesions sensitive to fluoride-driven remineralization processes.

Key words: Toothpaste, synchrotron radiation micro computed tomography (SR micro-CT), density, remineralization, fluoride, monochromatized X-ray beams, X-ray linear attenuation coefficient (X-ray LAC).