[Show abstract][Hide abstract] ABSTRACT: Purpose
The aim of this study was to investigate the susceptibility of Candida albicans and Candida glabrata biofilm development, in their intermediate and maturation stages, to the influence of silver nanoparticles (SN).
SN (5 nm) suspensions were synthesized via reduction of silver nitrate by a solution of sodium citrate. These suspensions were used to treat Candida biofilms for five hours, grown on acrylic surfaces for 24-h (intermediate stage) and 48-h (maturation stage), and their efficacy was determined by total biomass (using crystal violet staining) and colony forming units (CFUs) quantification.
SN promoted significant reductions (p < 0.05) in the total biomass and number of CFUs of Candida biofilms, ranging from 23% to 51.5% and 0.63 to 1.59-log10, respectively. Moreover, there were no significant differences in the total biofilm biomass (p > 0.05), when the different stages of biofilm development (24 or 48 h) were exposed to SN. Comparing the number of CFUs between 24- and 48-h biofilms treated with SN, a significant difference (p < 0.05) was found only for the C. albicans 324LA/94 strain.
In general, the intermediate and maturation stages of biofilm development do not interfere in the susceptibility of C. albicans and C. glabrata biofilms to SN. These findings are fundamental for the deployment of new therapies aimed at preventing denture stomatitis.
Journal of Prosthodontic Research 08/2014; 59(1). DOI:10.1016/j.jpor.2014.07.004
[Show abstract][Hide abstract] ABSTRACT: Our aim in this study was to evaluate how the chemical stability of silver nanoparticles (SNs) influences their efficacy against Candida albicans and C. glabrata biofilms. Several parameters of SN stability were tested, namely, temperature (50ºC, 70ºC, and 100ºC), pH (5.0 and 9.0), and time of contact (5 h and 24 h) with biofilms. The control was defined as SNs without temperature treatment, pH 7, and 24 h of contact. These colloidal suspensions at 54 mg/L were used to treat mature Candida biofilms (48 h) formed on acrylic. Their efficacy was determined by total biomass and colony-forming unit quantification. Data were analyzed using analysis of variance and the Bonferroni post hoc test (α = 0.05). The temperature and pH variations of SNs did not affect their efficacy against the viable cells of Candida biofilms (P > 0.05). Moreover, the treatment periods were not decisive in terms of the susceptibility of Candida biofilms to SNs. These findings provide an important advantage of SNs that may be useful in the treatment of Candida-associated denture stomatitis.
Medical Mycology 06/2014; DOI:10.1093/mmy/myu021 · 2.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Silver nanoparticles (SN) have been used to control Candidabiofilm formation. However, the loss of chemical stability could cause aggregation and subsequent precipitation of SN, and reduction in their effectiveness against biofilms.
Objective: The aim of this study was to assess the influence of SN chemical stability on their efficacy against Candida albicans (324LA/94, ATCC 10231) and Candida glabrata(D1, ATCC 90030) biofilms.
Methods: SN were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. Several parameters of stability of SN were tested, namely temperature (50, 70 and 100ºC), pH (5.0 and 9.0) and contact time (5h and 24h). The control was defined as SN without temperature treatment, pH 7.0 and 24h of contact time. These suspensions were used to treat Candida biofilms (48h) grown on acrylic, and their efficacy was determined by total biomass and viable cells quantification. The data were analyzed statistically by ANOVA and Bonferroni post-hoc test, with significance level at p<0.05.
Results: Preheating of SN at 100ºC and pH variation affected adversely the biomass of C. albicans 324LA/94 and C. glabrata strains, respectively. However, the temperature and pH variations of SN did not affect their efficacy against the viable cells of Candida biofilms (p>0.05). Moreover, the treatment periods were not decisive on the susceptibility of Candidabiofilms to SN.
Conclusion: Temperature and pH variations of SN affected differently the biomass and the sessile cells of Candida biofilms. Treatment periods did not seem to be decisive on the susceptibility of biofilms to SN. Finally, these findings provide important insights that may be useful in the treatment of denture stomatitis with formulations and materials containing SN.
[Show abstract][Hide abstract] ABSTRACT: Objective: To evaluate the effect of orbital agitation speed during single and mixed biofilm formation of Candida albicans and Candida glabrata oral and reference strains on the antifungal activity of silver nanoparticles (SN).
Methods: SN were synthesized by silver nitrate reduction with sodium citrate and stabilized with ammonia. Single and mixed biofilms of Candida species were formed under agitation of 10 and 120rpm on the surfaces of acrylic resin specimens into 24-wells microtiter plates. Then, biofilms were exposed to SN (54 and 108µg/mL) for 24h. Chlorhexidine digluconate (CHG) (108µg/mL) was used as control. After the treatments, biofilms were assessed by total biomass quantification (crystal violet staining) and colony forming units (CFU) enumeration.
Results: SN reduced similarly the biomass of single and mixed biofilms of Candida reference strains formed under 10 and 120 rpm. However, in general, the agitation speed interfered in the effectiveness of SN in reducing the total biofilm biomass for oral clinical isolates. Regarding CFUs quantification, SN were effective against the biofilms formed under both 10 and 120rpm.
Conclusion: The orbital agitation speed affected only the SN effectiveness in reducing the total biomass of Candida biofilms. So, the use of SN as an alternative treatment for oral candidosis should be more explored.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND: Although the long-term success of implant treatment has been well- established, failures can still occur and the smoking habit has been reported as a risk factor for implant loss. A literature review on the effects of smoking on the survival of dental implants was undertaken. METHODS AND RESULTS: Medline database was used to carry out the review with the keywords "osseointegration", "smoking" and "bone healing". The cigarette has more than 4,000 bioactive chemical components with potential toxic effects to human tissues including bone. Nicotine is the main component of the cigarette and it is frequently associated with bone healing failures. Since smoking negatively affects the osseointegration of dental implants, the main target is to quit the consumption of cigarettes. CONCLUSION: Nevertheless, the smoking habit should not be an absolute contraindication for implant treatment, but, patients should be advised that they are at a greater risk of implant failure.
Biomedical papers of the Medical Faculty of the University Palacky, Olomouc, Czechoslovakia 05/2013; 158(4). DOI:10.5507/bp.2013.037 · 1.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose: The aim of this study was to evaluate the impact of treatment with new complete dentures on oral health-related quality of life and satisfaction of edentulous patients attending the Prosthodontic Department in a Dental School in Brazil. Methods: A total of 70 edentulous subjects (37-86 years) treated by undergradute students at the Araçatuba Dental School, University of State of São Paulo, were accessed. A specific questionnaire for edentulous patients (EDENT) based on the Oral Health Impact Profile (OHIP-EDENT) was applied to collect information on patient oral health-related quality of life. Questions related to the personal satisfaction of the edentulous patients with their complete dentures were also included. The patients were accessed before the treatment, and 3 months after receiving the new dentures. Results: After rehabilitation with new complete dentures, all domains of OHIP-EDENT showed significant improvements. There was also a significant improvement in patient satisfaction after placement of new complete dentures. Furthermore, it was possible to observe association between upper denture satisfaction and age. Conclusion: Conventional complete dentures may have a positive impact on oral health-related quality of life and satisfaction of edentulous patients.
[Show abstract][Hide abstract] ABSTRACT: Objective: The tolerance of Candida biofilms to conventional antifungal drugs has stimulated the search for new therapies that could prevent or treat Candida-associated denture stomatitis. The objectives of this study were (i) to assess the antibiofilm activity of different silver nanoparticles (SN) suspensions against Candida albicans and Candida glabrata biofilms and (ii) to evaluate the effect of these nanoparticles on the matrix composition and the structure of Candida biofilms.
Method: SN of three different average sizes (5, 10 and 60 nm) were used in this study. Biofilms of an oral clinical isolate of C. albicans and C. glabrata were formed for 48 h. These biofilms were exposed to different concentrations of SN for a period of 24 h. Antibiofilm activity of SN was determined by total biomass quantification (using crystal violet staining) and colony forming units enumeration. The extracellular matrices of Candida biofilms were extracted and analyzed chemically in terms of proteins, carbohydrates and DNA. Scanning electron microscopy (SEM) and epifluorescence microscopy were used to analyze the structure and morphology of the biofilms.
Result: SN were effective in reducing total biomass (around 90%) of C. glabrata biofilms. All SN suspensions showed significant reduction of the number of cultivable cells at concentrations equal to or higher than 108 µg/mL. The particle size and the type of stabilizing agent did not interfere in the antibiofilm activity of SN. Interestingly, SN induce modifications in the contents of protein, carbohydrate and DNA of the extracellular matrices of Candida biofilms. SEM and epifluorescence investigations revealed structural differences in spatial arrangement and damage in the cell walls of biofilm cells, compared to the controls.
Conclusion: SN present therapeutic potential and might be useful in the treatment of denture stomatitis.
[Show abstract][Hide abstract] ABSTRACT: The prevalence of wearing and fracture of complete dentures was evaluated among edentulous patients treated in two dental schools in Brazil.
Acceptance and wearing of complete dentures are related to adaptive behaviour of edentulous patients. However, one reason that could interfere with the wearing dentures is their potential to fracture, which is still a common complication in denture rehabilitation practice.
Two hundred and twenty-four edentulous patients rehabilitated with complete dentures from 2000 to 2005 in Araçatuba and Araraquara Dental School, University of State of São Paulo, were assessed in 2006 and 2007 to answer a questionnaire about wearing and fracture of their dentures. Statistical analysis were performed using Epi Info software and chi-squared test to compare maxillary and mandibular data (α = 0.05).
Almost 26% of the patients did not wear their dentures, and among the remainder, the majority wore the maxillary denture. About 30% of the dentures were fractured, with higher prevalence in the maxillary arch (p = 0.003).
Discontinuation of wearing dentures was quite high, especially considering the treatment which was carried out in university clinics. Prevalence of fractures was also high, greater for the maxillary denture, and was one of the main reasons for non-wearing of complete dentures.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the overnight wearing and cleaning habits of complete denture wearers.
Successful complete denture treatment can be achieved when the patients are motivated and aware of appropriate denture wear and hygiene.
A sample of 224 complete denture wearers (162 women) aged 37-89 years was studied. Inclusion criteria comprised edentulous subjects who had received their new complete dentures between 2000 and 2005 in the Dental Clinic of the Araçatuba and Araraquara Dental School, São Paulo State University. Ethical approval was sought and granted. Subjects were interviewed using questions related to overnight denture wearing and denture cleaning habits. Possible statistical relationships among some of items were analysed by the chi-square test at 5% significance level.
Of the patients, 55.8% removed their dentures during the overnight period and 88% did this every day. Among them, 66.4% removed both dentures. Most of the patients used brushing with toothpaste (105 patients - 46.87%) as a cleaning method. More than a half of the subjects (63.4%) showed biofilm and calculus on their dentures.
The patients need instructions and motivation concerning denture hygienic and denture removal overnight.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the rat alveolar bone response after the implantation of experimental light-cured mineral trioxide aggregate (MTA) or Angelus MTA (Angelus, Londrina, Paraná, Brazil) by histological and fluorescence analysis.
Thirty Wistar Albino rats were divided into three groups. In the control group, empty polyethylene tubes were inserted into the rat alveolar sockets immediately after extraction. In the other groups, the tubes were filled with light-cured MTA or Angelus MTA. Five animals from each group were injected with calcein on day 7, alizarin on day 14, and oxytetracycline on day 21. On day 30, these animals were killed, and the right hemimaxillas were removed and histologically processed. Half of the maxillas were processed and stained with hematoxylin and eosin. The remaining maxillas were processed for fluorescence analysis and stained with Stevenel blue and alizarin red. New bone was histomorphometrically evaluated using a Merz grid.
The light-cured MTA presented a similar response when compared with Angelus MTA; it was characterized by a mild inflammatory response and complete bone healing. In the light-cured MTA group, the fluorescence areas were more evident at 21 days, showing an increase in bone formation. However, dystrophic mineralization was observed only with Angelus MTA.
It was concluded that both materials present a similar inflammatory response and bone healing, but dystrophic mineralization was observed only with Angelus MTA.
Journal of endodontics 02/2011; 37(2):250-4. DOI:10.1016/j.joen.2010.11.005 · 2.79 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The health of a peri-implant tissue is a critical factor for the long-term success of treatment with extraoral implants. However, infection and inflammation may occur and lead to implant loss and prostheses failure. Therefore, some postsurgical care as hygiene with soap and water, soft toothbrush, and Superfloss type dental floss and medication with anti-inflammatory and antibiotic are suggested to avoid complications. In addition, a thin and smooth layer of subcutaneous tissue in the peri-implant area should be preserved during implant insertion to favor the assistance recommended in this phase.
The Journal of craniofacial surgery 03/2010; 21(2):565-7. DOI:10.1097/SCS.0b013e3181d025a7 · 0.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Research has clarified the properties required for polymers that resist bacterial colonisation for use in medical devices. The increase in antibiotic-resistant microorganisms has prompted interest in the use of silver as an antimicrobial agent. Silver-based polymers can protect the inner and outer surfaces of devices against the attachment of microorganisms. Thus, this review focuses on the mechanisms of various silver forms as antimicrobial agents against different microorganisms and biofilms as well as the dissociation of silver ions and the resulting reduction in antimicrobial efficacy for medical devices. This work suggests that the characteristics of released silver ions depend on the nature of the silver antimicrobial used and the polymer matrix. In addition, the elementary silver, silver zeolite and silver nanoparticles, used in polymers or as coatings could be used as antimicrobial biomaterials for a variety of promising applications.
International journal of antimicrobial agents 04/2009; 34(2):103-10. DOI:10.1016/j.ijantimicag.2009.01.017 · 4.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Introducción: Se observó un considerable crecimiento del contingente poblacional de ancianos. Ellos son los mayores usuarios de medicamentos. Los cambios fisiológicos relacionados con el envejecimiento pueden alterar la propiedad farmacocinética y la farmacodinamia. El cuadro de declinación cognitiva, las limitaciones físicas y las enfermedades crónicas asociadas afectan la habilidad de usar adecuadamente los medicamentos. Objetivo: Indicar las principales clases farmacológicas administradas a pacientes geriátricos y los riesgos de la interacción medicamentosa en base a una revisión de literatura. Conclusión: La mayor parte de los ancianos hacen uso continuo de por lo menos tres fármacos, los más prescritos son aquellos destinados a problemas cardiovasculares y trastornos psíquicos.