Abstract Creating artificial caries-like lesions that mimic the complex changes observed in natural caries is essential for properly evaluating new strategies, dental materials, and devices designed to arrest their progression and avoid more costly and invasive treatments. Objective This study compared three protocols for developing artificial white spot lesions (WSL) using biofilm models. Methodology In total, 45 human enamel specimens were sterilized and allocated into three groups based on the biofilm model: Streptococcus sobrinus and Lactobacillus casei (Ss+Lc), Streptococcus sobrinus (Ss), or Streptococcus mutans (Sm). Specimens were incubated in filter-sterilized human saliva to form the acquired pellicle and then subjected to the biofilm challenge consisting of three days of incubation with bacteria (for demineralization) and one day of remineralization, which was performed once for Ss+Lc (four days total), four times for Ss (16 days total), and three times for Sm (12 days total). After WSL creation, the lesion fluorescence, depth, and chemical composition were assessed using Quantitative Light-induced Fluorescence (QLF), Polarized Light Microscopy (PLM), and Raman Spectroscopy, respectively. Statistical analysis consisted of two-way ANOVA followed by Tukey’s post hoc test (α=0.05). WSL created using the Ss+Lc protocol presented statistically significant higher fluorescence loss (ΔF) and integrated fluorescence (ΔQ) in comparison to the other two protocols (p<0.001). Results In addition, Ss+Lc resulted in significantly deeper WSL (137.5 µm), followed by Ss (84.1 µm) and Sm (54.9 µm) (p<0.001). While high mineral content was observed in sound enamel surrounding the WSL, lesions created with the Ss+Lc protocol showed the highest demineralization level and changes in the mineral content among the three protocols. Conclusion The biofilm model using S. sobrinus and L. casei for four days was the most appropriate and simplified protocol for developing artificial active WSL with lower fluorescence, higher demineralization, and greater depth. carieslike like strategies materials treatments (WSL models total 4 Ss+Lc, SsLc , Lc (Ss+Lc) Ss, (Ss) Sm. . (Sm) filtersterilized filter remineralization total) 16 (1 12 total. creation depth Lightinduced induced QLF, QLF (QLF) PLM, PLM (PLM) Spectroscopy respectively twoway way Tukeys Tukey s α=0.05. α005 α α=0.05 0 05 (α=0.05) ΔF (ΔF ΔQ (ΔQ p<0.001. p0001 p p<0.001 001 (p<0.001) addition 137.5 1375 137 5 (137. µm, µm 84.1 841 84 1 (84. 54.9 549 54 9 (54. S L (Ss+Lc (Ss (Sm ( (QLF (PLM α00 α=0.0 (α=0.05 p000 p<0.00 00 (p<0.001 137. 13 (137 84. 8 (84 54. (54 α0 α=0. (α=0.0 p00 p<0.0 (p<0.00 (13 (8 (5 α=0 (α=0. p0 p<0. (p<0.0 α= (α=0 p<0 (p<0. (α= p< (p<0 (α (p< (p

Resumo O objetivo deste estudo foi comparar a eficácia do extrato de semente de uva (ESU), hipoclorito de cálcio [Ca(ClO)2] e hipoclorito de sódio (NaOCl) como soluções irrigadores quando utilizadas com instrumentos reciprocantes e rotatórios para desinfecção de canais radiculares infectados com Enterococcus faecalis. Raízes mesio-vestibulares de molares inferiores foram preparados e inoculados com E. faecalis por 21 dias. As raízes foram aleatoriamente divididas em 8 grupos (n=11) de acordo com a técnica de instrumentação e protocolo de irrigação: ProTaper Next ou Reciproc R25 associados com soro fisiológico (grupo controle), Ca(ClO)2 6%, NaOCl 6% ou ESU 50%. A atividade antimicrobiana foi determinada pela redução do número de Unidades Formadoras de Colonias (UFCs) coletadas antes e após a instrumentação e expressas em porcentagens de redução. Os dados foram analisados estatisticamente pelos testes ANOVA seguido pelo teste complementar de Tukey HSD (p<0,05). Não foi encontrado diferença estatisticamente significante na redução bacteriana entre os sistemas ProTaper Next e Reciproc R25 (p>0.05), independente da solução irrigadora usada. Além disso, todas as soluções ativas (NaOCl, ESU e Ca(ClO)2) mostraram similar potencial em reduzir a quantidade de bactérias (p>0.05) e foram significativamente mais efetivas que o soro fisiológico (p<0.05). Pode-se concluir que o ESU e o Ca(ClO)2 apresentam potencial para aplicação clínica como irrigantes endodônticos uma vez que apresentaram efetividade antimicrobiana contra o E. faecalis.

Abstract The aim of this study was to compare the efficacy of grape seed extract (GSE), calcium hypochlorite [Ca(ClO)2], and sodium hypochlorite (NaOCl) irrigant solutions with rotary or reciprocating instrumentation for disinfection of root canals inoculated with Enterococcus faecalis. The mesiobuccal root canals of mandibular molars were prepared and inoculated with Enterococcus faecalis for 21 days. The roots were then randomly divided into the following eight experimental groups (n=11) according to the instrumentation technique and disinfection protocol: ProTaper Next or Reciproc R25 with sodium chloride (control group), 6% NaOCl, 6% Ca(ClO)2, or 50% GSE used for irrigation during instrumentation. The antimicrobial activity was determined on the basis of a reduction in colony-forming units (CFUs) counted on bacterial samples collected before and after root canal instrumentation and expressed as a percentage of reduction. Data were evaluated by two-way ANOVA followed by Tukey HSD post-hoc tests (p<0.05). No significant differences were observed in bacterial reduction between the ProTaper Next and Reciproc R25 systems (p>0.05), regardless of the irrigant solution used. Furthermore, all active solutions (6% NaOCl, 50% GSE, and 6% Ca(ClO)2) showed similar potential to reduce bacterial counts (p>0.05) and were significantly more effective than sodium chloride (control) (p<0.05). The results suggest that the GSE and Ca(ClO)2 have potential clinical application as irrigant solutions in endodontic therapy since they present bactericidal efficacy against Enterococcus faecalis.