The quadrants most affected by the development of lesions in our study were, in decreasing order, the gingival, distal, mesial, and occlusal areas, as in a previ-ous report 17 —a pattern that probably reflects the rela-tive difficulty of cleaning these regions. The gingival subface, the area most prone to white-spot lesions, did exhibit a significant benefit from SeLECT Defense™. The positive effects of fluoride varnish noted in the current study corroborate the findings of previous reports 16-18 which confirmed the decrease in lesion depth (50% -86%) with the use of fluoride varnish. However, complete removal of Duraphat ® was noted after approximately nine days, while Fluor Protector™ was on the enamel surface after the 27-day study. So, although varnishes provide a significant benefit to high caries risk patients, one drawback is that they often require multiple in-office applications Results of our study confirmed that organoselenium sealant inhibits bacterial plaque formation on human teeth and the stability of the antibacterial effect over six months. The mechanism of its action differs totally from varnish. This agrees with previous studies, which suggested that the gradual release of fluoride compro-mises the antibacterial effect of the fluoride-containing varnish. 13-21 As a result, over time, the efficiency of these dental varnishes would be compromised, which necessitates the recharge of more fluoride salt to enhance their antimicrobial activity. In contrast, because of the covalent attachment of selenium to the polymer of the sealant, only very small amounts of unpolymerized selenium may be released from the sealant. The significant difference between bacterial attachment and biofilm formation on varnish vs. organo-selenium dental sealants is likely to be due to the O 2 , catalytically produced by the organo-sele-nium, which causes oxidative stress that damages the bacterial cell walls and DNA. 37,38 Also, a previous study showed that organo-selenium in polymer form can generate superoxide radicals. 39 Superoxide radicals have a toxicity for microorganisms 30 but not for humans, even in elevated amounts. In vivo and in vitro university studies 39-41 have proven SeLECT Defense™ effective as an antimicrobial agent and as a prophylactic against demineralization, while simultaneously displaying adequate shear bond strength and durability when used with Transcend™ adhesive (3M Unitek) or with SeLECT Defense™ adhe-sive. Other sealants and protective coatings have displayed demineralization and cavity prevention prop-erties, but neither their endurance nor long-term effec-tiveness has been well documented. Some researchers have even questioned their overall effectiveness and disputed if they make a statistical difference. 19,42,43 Additionally, SeLECT Defense™ offers clinicians the appealing feature of not requiring them to change their routine bonding protocol. Instead of using unfilled sealants or those without antimicrobial effects, they can simply incorporate this new sealant with their usual bonding techniques and have confidence that it will minimize the demineralization and gingival inflamma-34 Winter 2014 JAOS tion caused by plaque. In addition, bacteria cannot live under the dental sealant. 41 The results of this in vivo clinical trial study suggest that SeLECT Defense™ may be a promising new anti-microbial sealant. However, further future clinical stud-ies are needed to determine if Select Defense™’s clinical performance is as successful as the results obtained here. Conclusions • Both varnish and SeLECT Defense™ sealant can decrease demineralization. • SeLECT Defense™ is more effective in decreasing demineralization after three and six months . • The gingival part is most affected by demineralization. Acknowledgements The author would like to thank the Egyptian Ministry of Higher Education and Scientific Research for funding. References 1. Cacciafesta V, Sfondrini MF, Stifanelli P, Scribante A, Klersy C. Effect of chlorhexidine application on shear bond strength of brackets bonded with a resin-modified glass ionomer. Am J Orthod Dentofacial Orthop. 2006;129:273–276. 2. Hallgren A, Oliveby A, Twetman S. Fluoride concentration in plaque adjacent to orthodontic appliances retained with glass ionomer cement. Caries Res. 1993;27:51–54. 3. Matalon S, Slutsky H, Weiss EI. Antibacterial properties of 4 orthodontic cements. Am J Orthod Dentofacial Orthop. 2005;127:56–63. 4. Sehgal VV, Shetty S, Mogra S, Bhat G, Eipe M, Jacob S, Prabu L. Evaluation of antimicrobial and physical properties of orthodon-tic composite resin modified by addition of antimicrobial agents—an in-vitro study. Am J Orthod Dentofacial Orthop. 2007;131:525–529. 5. Sukontapatipark W, El-Agroudi MA, Selliseth NJ, Thunold K, Selvig KA. Bacterial colonization associated with fixed orthodontic appliances. A scanning electron microscopy study. Eur J Orthod. 2001;23:475–484. 6. Gorton J, Featherstone JD. In vivo inhibition of demineralization around orthodontic brackets. Am J Orthod Dentofacial Orthop. 2003;123:10-4. 7. Sturdevant CM, Raberson TM, Hyman H, Sturdevant GR. The art and science of operative dentistry. St Louis: Mosby; 2002. p. 67-95. 8. Schmit JL, Staley RN, Wefel JS, Kanellis M, Jacobsen JR, Keenan PJ. Effect of fluoride varnish on demineralization adjacent to brackets bonded with RMGI cement. Am J Orthod Dentofacial Orthop. 2002;122:125-34. 9. Heintz S, Georg P. Oral health for the orthodontic patients. Philadelphia: Mosby; 1999. p. 2-9, 94-7. 10. Evrenol BI, Kucukkeles N, Arun T, Yarat A. Fluoride release capaci-ties of four different orthodontic adhesives. J Clin Pediatr Dent. 1999;23:315-9. 11. Todd MA, Staley RN, Kanellis MJ, Donly KJ, Wefel JS. Effect of fluoride varnish on demineralization adjacent to orthodontic brackets. Am J Orthod Dentofacial Orthop. 1999;116:159-67.
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