Abstract Fixed orthodontic appliances may lead to biofilm accumulation around them that may increase caries risk. This study aimed to evaluate the influence of quaternary ammonium methacrylates (QAMs) on the physicochemical properties, cytotoxicity, and antibacterial activity of adhesive resins for orthodontic purposes. Methodology: A base resin was prepared with a comonomer blend and photoinitiator/co-initiator system. Two different QAMs were added to the base adhesive: dimethylaminododecyl methacrylate at 5 wt.% (DMADDM) or dimethylaminohexadecyl methacrylate (DMAHDM) at 10 wt.%. The base adhesive, without QAMs, (GC) and the commercial Transbond™ XT Primer 3M (GT) were used as control. The resins were tested immediately and after six months of aging in the water regarding the antibacterial activity and shear bond strength (SBS). The antibacterial activity was tested against Streptococcus mutans via metabolic activity assay (MTT test). The groups were also tested for the degree of conversion (DC) and cytotoxicity against keratinocytes. Results: The resins containing QAM showed antibacterial activity compared to the commercial material by immediately reducing the metabolic activity by about 60%. However, the antibacterial activity decreased after aging (p<0.05). None of the groups presented any differences for SBS (p>0.05) and DC (p>0.05). The incorporation of DMADDM and DMAHDM significantly reduced the keratinocyte viability compared to the GT and GC groups (p<0.05). Conclusion: Both adhesives with QAMs showed a significant reduction in bacterial metabolic activity, but this effect decreased after water aging. Lower cell viability was observed for the group with the longer alkyl chain-QAM, without significant differences for the bonding ability and degree of conversion. The addition of QAMs in adhesives may affect the keratinocytes viability, and the aging effects maybe decrease the bacterial activity of QAM-doped materials.

Abstract Although resin composites are widely used in the clinical practice, the development of recurrent caries at composite-tooth interface still remains as one of the principal shortcomings to be overcome in this field. Objectives To evaluate the activity against S. mutans biofilm of model resin composites incorporating different concentrations of ZnO-nanoparticles (ZnO-NP) and characterize their physicochemical properties. Materials and Methods Different concentrations of ZnO-NP (wt.%): E1=0, E2=0.5, E3=1, E4=2, E5=5 and E6=10 were incorporated into a model resin composite consisting of Bis-GMA-TEGDMA and barium borosilicate particles. The activity against S. mutans biofilm was evaluated by metabolic activity and lactic acid production. The following physicochemical properties were characterized: degree of conversion (DC%), flexural strength (FS), elastic modulus (EM), hardness (KHN), water sorption (Wsp), water solubility (Wsl) and translucency (TP). Results E3, E4, E5 and E6 decreased the biofilm metabolic activity and E5 and E6 decreased the lactic acid production (p<0.05). E6 presented the lowest DC% (p<0.05). No significant difference in FS and EM was found for all resin composites (p>0.05). E5 and E6 presented the lowest values of KHN (p<0.05). E6 presented a higher Wsp than E1 (p<0.05) and the highest Wsl (p<0.05). The translucency significantly decreased as the ZnO- NP concentration increased (p<0.05). Conclusions The incorporation of 2 – 5 wt.% of ZnO-NP could endow antibacterial activity to resin composites, without jeopardizing their physicochemical properties.

Abstract Objectives This study analyzed the capacity of Candida spp. from dental biofilm of HIV infected (HIV+) children to demineralize primary molar enamel in vitro by Transversal Microhardness (TMH), Polarized Light Microscopy (PLM) and the quantity of calcium ions (Ca2+) released from the enamel. Material and Methods Candida spp. samples were isolated from the supragingival biofilm of HIV+ children. A hundred and forty (140) enamel blocks were randomly assigned to six groups: biofilm formed by C. albicans (Group 1); mixed biofilm formed by C. albicans and C. tropicalis (Group 2); mixed biofilm formed by C. albicans and C. parapsilosis (Group 3); mixed biofilm formed by C. albicans, C. parapsilosis and C. glabrata (Group 4); biofilm formed by C. albicans ATCC (Group 5) and medium without Candida (Group 6). Enamel blocks from each group were removed on days 3, 5, 8 and 15 after biofilm formation to evaluate the TMH and images of enamel were analyzed by PLM. The quantity of Ca2+ released, from Groups 1 and 6, was determined using an Atomic Absorption Spectrophotometer. The SPSS program was used for statistical analysis and the significance level was 5%. Results TMH showed a gradual reduction in enamel hardness (p<0.05) from the 1st to 15th day, but mainly five days after biofilm formation in all groups. The PLM showed superficial lesions indicating an increase in porosity. C. albicans caused the release of Ca2+ into suspension during biofilm formation. Conclusion Candida species from dental biofilm of HIV+ children can cause demineralization of primary enamel in vitro.

Abstract: The study aimed to investigate the effects of bacterial biofilms on changes in the surface microhardness of enamel treated with casein phosphopeptide—amorphous calcium phosphate (CPP-ACP) with and without fluoride. Human enamel blocks with incipient caries-like lesions were divided into four groups of 13: G1: Saliva (Control); G2: fluoride dentifrice (Crest™, 1100 ppm as NaF); G3: CPP-ACP (MI Paste; Recaldent™); and G4: CPP-ACPF (MI Paste Plus; Recaldent™ 900 ppm as NaF). The specimens were soaked in demineralizing solution for 6 h and remineralized in artificial saliva for 18 h alternately for 10 days. The dentifrice was prepared with deionized water in a 1 : 3 ratio (w/w) or applied undiluted in the case of the CPP-ACP group. The surface microhardness (SMH) was evaluated at baseline, after artificial caries, after pH cycling and treatment with dentifrices, and after incubation in media with Streptococcus mutans for biofilm formation. The biofilms were exposed once a day to 2% sucrose and the biofilm viability was measured by MTT reduction. The percentage of change in surface microhardness (%SMHC) was calculated for each block. The data were analyzed by nonparametric test comparisons (α = 0.05). The %SMHC values observed in G2 were different from those of G1, G3, and G4 (p < 0.05). After biofilm formation, %SMHC was positive in G2 and G4 when compared to G1 and G3, but resistance to demineralization after biofilm formation was similar in all groups. In conclusion, the presence of biofilms did not influence the treatment outcomes of anticaries products.

The present study evaluated the antimicrobial activity of three root canal irrigants against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. These microorganisms were incubated in the presence of citric acid (6 and 10%), EDTA (17%), and NaOCl (0.5, 1.0, 2.5, and 5.25%). Agar diffusion tests were performed and redox indicator resazurin was used to evaluate the inhibitory effect of the irrigants on the metabolic activity of these microorganisms. The mean diameters of the inhibition zones for the C. albicans cultures were 11.6 mm (17% EDTA), 5.5 mm (0.5% NaOCl), 12.9 mm (1% NaOCl), 22.1 mm (2.5% NaOCl), and 28.5 mm (5.25% NaOCl). The mean diameters of the inhibition zones for E. faecalis were 2.8 mm (1% NaOCl), 5.4 mm (2.5% NaOCl), and 8.3 mm (5.25% NaOCl). For S. aureus, the mean values were 8.0 mm (17% EDTA), 3.0 mm (1% NaOCl), 8.8 mm (2.5% NaOCl), and 10.0 mm (5.25% NaOCl). Most of the irrigant solutions presented effective antimicrobial activity against C. albicans. A high inhibitory effect on the metabolic activity of E. faecalis was detected when the microorganisms were incubated with 17% EDTA. The same result was reached when S. aureus was incubated in the presence of > 2.5% NaOCl. Altogether, these results indicate that 2.5% and 5.25% NaOCl are microbicides against S. aureus while 0.5% and 1% NaOCl are only microbiostatic against the tested bacteria. The 6% and 10% citric acid as well as 17% EDTA did not affect the viability of any of the assayed microorganisms.

Este estudo tem como objetivo determinar a experiência de cárie em crianças infectadas pelo HIV, correlacionada com a classificação clínica e imunológica (CDC³, 1994). Participaram da pesquisa 92 crianças (50 meninas e 42 meninos), com média de idade de 5,77 ± 3,31 anos (6 meses a 13 anos), com diagnóstico definitivo para o HIV, todos pacientes com atendimento ambulatorial. Foi realizado exame bucal para determinar os índices ceo/CPOD e os dados de história médica foram coletados dos prontuários médicos. Na dentição decídua de crianças mais jovens (até 5 anos), apesar de a prevalência de cárie ter apresentado valores maiores naquelas mais comprometidas clínica e imunologicamente, não houve diferença estatisticamente significante entre as diversas categorias de classificação. Nas crianças de maior idade, isto também foi observado, apesar de terem sido encontrados valores de CPOD maiores nas crianças mais doentes.

This research aims to determine the relationship between the prevalence of caries and clinical and immunological classification in HIV-infected children. Ninety-two outpatients (42 male and 50 female subjects) with definitive diagnosis of HIV infection took part in this research. The patients were examined in order to determine the prevalence of caries (dmf and DMFT indexes), and medical data were collected from their medical records. The mean age of the subjects was 5.77 years. Although no statistical differences were found, young patients (up to 5 years old) had more caries when they were more clinically and immunologically compromised. The same fact was observed regarding older children.