International Journal of Public Health Science (IJPHS) Vol. 12, No. 1, March 2023, pp. 64~71 ISSN: 2252-8806, DOI: 10.11591/ijphs.v12i1.22251  64 Journal homepage: http://ijphs.iaescore.com In vitro study of the preventive activity of fluoride varnish by X-ray diffraction Dobrinka Mitkova Damyanova, Siyana Atanasova Department of Pediatric Dental Medicine, Faculty of Dental Medicine, Medical University of Varna, Varna, Bulgaria Article Info ABSTRACT Article history: Received Jul 19, 2021 Revised Nov 1, 2022 Accepted Nov 21, 2022 In exogenous prophylaxis, fluoride is applied directly to the tooth surface through various gels, varnishes, foams, and toothpaste. According to the global burden of disease study conducted in 2017, more than 530 million children worldwide suffer from dental caries in their primary dentition. There are few developments in the selection of non-invasive methods in the application of mineralizing varnishes. The researchers investigated experimentally, in-vitro the preventive activity of the fluoride varnish Clinpro™ White Varnish with TCP 3M (CV), using a modern method of X- ray diffraction. The 20 temporary teeth were extracted due to physiological changes. Place of study was UMDC - city of Varna and Institute of Physical Chemistry "Academician Rostislav Kaishev" of the Bulgarian Academy of Sciences, Sofia. Demineralization is carried out with 37% phosphoric acid (i-gel – etching gel) and applied to the smooth temporary enamel surfaces for 30 seconds. The models were then washed and dried with a water and air jet. Remineralization was performed with CV. The formation of small globules of calcium fluoride. The coating is composed mainly of fluorapatite. With the modern method of X-ray diffraction, it was proved that exogenous fluoride prophylaxis and remineralization therapy are effective methods of prevention and treatment of initial caries lesions. Keywords: Fluoride varnish Primary teeth Demineralization Remineralization Prevention This is an open access article under the CC BY-SA license. Corresponding Author: Dobrinka Damyanova Department of Pediatric Dental Medicine, Faculty of Dental Medicine, Medical University of Varna 84, Tsar Osvoboditel, 9000 Varna, Bulgaria Email: dr_damyanova@abv.bg 1. INTRODUCTION Fluorine prophylaxis is divided into endogenous and exogenous. It is important for endogenous prevention that fluoride enters the body through the digestive system and is subsequently transported to the bones and teeth through the blood. In exogenous prophylaxis, fluoride is applied directly to the tooth surface through various sources (gels, varnishes, foams, and toothpaste). The fluoride in all sources used for fluoride prophylaxis is not in the free state but is bound in chemical compounds such as NaF (sodium fluoride) and other compounds that give it stability. More in-vivo and in-vitro studies are needed to investigate this effect. According to Bonetti and Clarkson [1], many previous publications support fluoride varnish as a caries- inhibiting trace element. From our available literature, six Cochrane systematic reviews, including 200 studies and more than 80,000 participants, found the effectiveness of fluoride varnish applied in clinical settings two to four times a year to "arrest" and stop the development of dental caries and in the two functional dentitions. Success from fluoride varnish applications appears to be available regardless of high caries risk, initial dental status, fluoride exposure, prescription of fluoride toothpaste, and even prior patient prophylaxis. The efficacy of fluoride varnish is recognized in our clinical practice guidelines worldwide, but the application of these algorithms may still present some problems. Clinical use of fluoride varnish in the