Antibacterial effect of silver nanoparticles mixed with calcium hydroxide or chlorhexidine on multispecies biofilms

• Published in: Odontology Vol. 109; no. 4; pp. 802 - 811
• Main Authors: Tülü, G., Kaya, B. Üreyen, Çetin, E. Sesli, Köle, M.
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.10.2021; Springer Nature B.V
• Subjects: Actinomyces; Antibacterial activity; Bacteria; Biofilms; Calcium hydroxide; Chlorhexidine; Confocal microscopy; Dentistry; Enterococcus faecalis; Kruskal-Wallis test; Lactobacillus acidophilus; Medicine; Nanoparticles; Oral and Maxillofacial Surgery; Original Article; Silver; Streptococcus mutans; Multispecies biofilm; Chlorhexidine; Antibacterial; Calcium hydroxide; Silver nanoparticles
• ISSN: 1618-1247; 1618-1255
• DOI: 10.1007/s10266-021-00601-8

The purpose is to evaluate the antibacterial effects of the silver nanoparticles (AgNPs) (Nanografi, METU Teknokent, Ankara, Turkey) mixed with calcium hydroxide (Ca(OH) 2 ) (Ultracal XS, Ultradent, St Louis, US) or chlorhexidine gel (CHX) (Gluco-Chex, Cerkamed, Stalowa Wola, Poland) against a multispecies biofilm, by confocal laser scanning microscopy (CLSM) and culture-based analysis. Dentine blocks were inoculated with Enterococcus faecalis , Streptococcus mutans , Lactobacillus acidophilus and Actinomyces naeslundii for 1 week. Infected dentine blocks were randomly divided into groups according to medication; saline solution (SS), Ca(OH) 2 , Ca(OH) 2  + AgNP, 2%CHX gel and 2%CHX gel + AgNP and time of application: 1 and 7 days (all groups, n  = 5). Bacterial samples were collected before and after medication to quantify the bacterial load. Biofilm elimination was quantitatively analyzed by Live/Dead BacLight Bacterial Viability staining and CLSM. The addition of AgNPs to Ca(OH) 2 increased the effectiveness of medicament in terms of bacterial reduction in both application times (1 and 7 days) ( p  < 0.05: ANOVA, Tukey’s test) according to culture-based analysis. The CLSM images revealed that mixture of AgNP with CHX killed significantly more bacteria when compared with all other medicaments at 1- and 7-day application times ( p  < 0.05 and p  > 0.05, respectively: Kruskal–Wallis, Dunn post hoc tests). The efficacy of Ca(OH) 2 mixed with AgNPs was superior to Ca(OH) 2 used alone in both application times ( p  < 0.05) according to CLSM analysis. The present study put forth the potential use of AgNPs mixed with Ca(OH) 2 or CHX on multispecies ( Enterococcus faecalis, Streptococcus mutans, Lactobacillus acidophilus and Actinomyces naeslundii ) biofilm in 1 and 7day application periods.