Effects of Baseplates of Orthodontic Appliances with in situ generated Silver Nanoparticles on Cariogenic Bacteria: A Randomized, Doubleblind Cross-over Clinical Trial

Abstract

Aim Polymethyl-methacrylate (PMMA) is commonly used primarily for baseplates of orthodontic appliances (BOA). The activities of cariogenic bacteria in biofilm on these surfaces may contribute to dental caries, gingival inflammation and periodontal disease. The PMMA incorporated with nanoparticles of silver (NanoAg-I-PMMA) and NanoAg in situ in PMMA (NanoAg-IS-PMMA) have been shown to control the growth of cariogenic bacteria, but clinical trial of anti-cariogenic application of these novel materials in orthodontics has not been evaluated. The main aim of the study is to compare the clinical effectiveness of using NanoAg-IS-PMMA and NanoAg-I-PMMA for construction of new BOA in inhibiting the planktonic growth and biofilm formation of the cariogenic bacteria. Materials and methods Twenty four patients with a median age of 12.6 years (7-15) harboring Streptococcus mutans, Streptococcus sobrinus and Lactobacillus acidophilus as well as Lactobacillus casei participated in the randomized, doubleblind, cross-over study. The experimental BOA, NanoAg-ISBOA and NanoAg-I-BOA, contained 0.5% w/w NanoAg while the control BOA was standard PMMA. Antibacterial effect of NanoAg-IS-BOA and NanoAg-I-BOA was assessed against test cariogenic bacteria by planktonic and biofilm bacterial cells growth inhibition. Results The average levels of test cariogenic bacteria in saliva decreased about 2 to 70 fold (30.9-98.4%) compared to baseline depending on the microorganism type and test BOA. Biofilm inhibition analysis demonstrated that NanoAg-I-BOA and NanoAg-IS-BOA inhibited the biofilm of all test bacteria by 20.1 to 79.9% compared to BOA. NanoAg-IS-BOA had a strong anti-biofilm effect against S. mutans, S. sobrinus and L. casei. However, NanoAg-I-BOA showed only slight antibiofilm effects on test bacteria. Most notably, at all period of the clinical trial, NanoAg-IS-BOA showed a higher antibacterial activity than NanoAg-I-BOA. Conclusion Based on the novel data that presented here, the NanoAg-IS-BOA had strong antimicrobial activity in the planktonic phase and subsequent biofilm formation of the cariogenic bacteria. Clinical significance Wearing of NanoAg-IS-BOA has the potential to minimize dental plaque formation and caries during orthodontic treatment. How to cite this article Ghorbanzadeh R, Pourakbari B, Bahador A. Effects of Baseplates of Orthodontic Appliances with in situ generated Silver Nanoparticles on Cariogenic Bacteria: A Randomized, Double-blind Cross-over Clinical Trial. J Contemp Dent Pract 2015;16(4):291-298.

<p>Use of Silver Nanomaterials for Caries Prevention: A Concise Review</p>

“…Four publications use an animal study or clinical trial to obtain the authentic antimicrobial efficiency of silver nanomaterial. 13,[28][29][30] Silver nanoparticles bring forth an antibacterial effect for silver nanomaterials. Although the exact mechanism of silver nanoparticles' antibacterial effects has not been entirely clarified, various antibacterial actions have been proposed.…”

“…Most studies measured bactericidal properties in vitro, whereas only four studies were operated in vivo, including two animal studies and two clinical trials. 13,[28][29][30] The results of the minimum inhibitory concentration and the minimum bactericidal concentration of silver nanomaterials against cariogenic bacteria have high degrees of variation in different studies. [31][32][33] The agar diffusion test demonstrated that disks treated with silver nanomaterials have larger inhibition zones compared with disks treated with water.…”

Antiadherence and Antimicrobial Properties of Silver Nanoparticles against Streptococcus mutans on Brackets and Wires Used for Orthodontic Treatments

“…Although our results might support this possible argument, more studies that determine the effect of AgNPs according to the corrosion level, topographic alterations, roughness, ion release, and other important properties of the most used orthodontic archwires should be investigated. In addition, the AgNPs have also been used for other different applications in the orthodontic field; the results of those investigations demonstrate that the orthodontic appliances with AgNPs have the ability to improve their antibacterial properties in several types of microorganisms involved in the white spots [36][37][38][39]. Our results suggest that the AgNP samples used in this study have the potential to be an excellent antimicrobial alternative with antiadherence properties that might facilitate the prevention of white spots caused by the S. mutans bacteria during the orthodontic therapeutics for the most conventional orthodontic appliances.…”

Anti-biofilm Activity as a Health Issue

“…Most anti-biofilm based randomized clinical trials have focused on infections associated with biofilm formation on abiotic surfaces: medical devices (especially ventilator-associated pneumonia and catheter-related infections) or dental surfaces. In these randomized clinical trials, the main strategy used to successfully control biofilm formation was the use of surface-coated ( Berra et al, 2008 ; Kollef et al, 2008 ) or surface-treated catheters ( Scannapieco et al, 2009 ; Quintas et al, 2015 ) and/or changes in surface composition of the device ( Ghorbanzadeh et al, 2015 ). The last paragraph of this review will focus on these different strategies, with special emphasis on their advantages and limitations.…”