Impact of chronic orofacial pain of temporomandibular disorder and anxiety on the academic performance of dental students / Impacto da dor orofacial crônica da disfunção temporomandibular e ansiedade no desempenho acadêmico de estudantes de odontologia

Introduction: The presence of chronic pain and mood disorders can be related to the performance of intellectual and technical tasks. Objective: This study evaluated the correlation between anxiety level, chronic orofacial pain of temporomandibular disorders (TMD), and academic performance in dental students. Methods: One hundred ninety-five students (74 men and 121 women) answered the Spielberger's trait­state anxiety inventory to evaluate the level of anxiety; the Research Diagnostic Criteria for TMD (RDC/TMD) was used to analyze chronic orofacial pain of TMD, and the academic performance was evaluated through the average grade of all college subjects concluded by the students. Correlations between the presence of chronic orofacial pain of TMD, trait, and state anxiety levels, chronic pain grade (CPG), chronic pain intensity (CPI), and academic performance were tested using Pearson's correlation test. Results: The mean age of the students was 21.8 years (SD=2.3). Chronic TMD was observed in 37.5% of the students. The majority of students had moderate trait and state anxiety. A significant correlation was observed between traitanxiety level and CPG (r=0.148, p=0.044), and CPI (r=0.187, p=0.009). No significant correlation was found between academic grade and presence of chronic pain of TMD (r=0.041, p=0.571), trait (r=0.079, p=0.273) and state-anxiety (r=0.107, p=0.136). Conclusion: The CPG and CPI increase in participants with higher trait-anxiety levels, however, no significant correlation was found between academic performance and trait/state anxiety or chronic orofacial pain of TMD.

Blastoid variant of mantle cell lymphoma in palatine tonsil.

Blastoid variant of mantle cell lymphoma (MCL) is an aggressive and extremely rare malignancy. MCL may be diagnosed in lymph nodes and/or extranodal sites exhibiting a poor prognosis. MCL with primary presentation in palatine tonsils has been rarely reported. Herein, we report the case of a 73-year-old man with a painless nodular mass on the right palatine tonsil. A biopsy was performed, and microscopic analysis revealed a neoplasm composed of small to medium sized lymphocytes with finely dispersed chromatin, roundish nucleus and many mitoses. The tumor cells were positive for CD20 (L26), CD5 (4C7), Cyclin D1 (EP12), Bcl2 (124) and Ki-67 (MIB-1; 90%), and negative for Bcl6 (PG-B6p), MUM1 (MUM1p) and CD3 (Polyclonal). These findings led to the diagnosis of blastoid variant of MCL. Diagnostic workup with computed tomography scan excluded other sites of disease. The patient was treated successfully with cyclophosphamide, doxorubicin, vincristine and prednisolone (mini-CHOP regimen). Although the blastoid variant of MCL is rare, it should be included in the differential diagnosis of rapid-growing masses in the palatine tonsil.

Effect of processing methods on the cytotoxicity of methyl methacrylate-based ocular prostheses: An in vitro study.

The study evaluated the influence of cycles and methods of an ocular prosthesis resin on cytotoxicity toward human conjunctival cells. Resins were polymerized by water bath (WB, 74 °C or 100 °C for 30 min to 9 h), microwave (MW, 1200 W, 3 to 14 min and 30 s at 0 to 720 W), or autopolymerization (AP, room temperature for 20 min ± 60 °C for 30 min). Degree of conversion (DC), cytotoxicity, level of inflammatory mediators, gene expression of different markers, and apoptosis were evaluated. Data were submitted to ANOVA and Tukey test (p < 0.05). WB with longer processing time at higher temperature had highest DC (85.6%) and higher TGF ß1-gene expression (1.39); long cycle low power MW showed lowest DC (69.6%), lower cell proliferation (85.4%, MTT), and large IL-2 release (39,297 ng/mL). AP with additional processing time showed lower cell proliferation (75.3%, Alamar Blue), and AP polymerized at room temperature showed higher CASP 9-gene expression (1.21). AP methods showed higher IL-6 release (>277 pg/mL). Short cycle medium power MW had higher IL-23 release (534.2 pg/mL). MW (long and short cycles) and AP polymerizations have triggered a more intense inflammatory response. Among methods recommended by the manufacturer, WB showed high DC and less cytotoxicity.

Biocompatible silver nanoparticles incorporated in acrylic resin for dental application inhibit Candida albicans biofilm.

BACKGROUND: Although silver nanoparticles (SNP) have proven antimicrobial activity against different types of microorganisms, the effect of SNP incorporation into acrylic resin to control Candida albicans biofilm formation aiming at the prevention of Candida-associated denture stomatitis has not yet been fully elucidated. OBJECTIVES: This study aimed to evaluate the antimicrobial effect of an acrylic resin containing SNP on C. albicans biofilm growth, the flexural strength of this material and tissue reaction in the subcutaneous connective tissue of rats to SNP. METHOD: SNP were synthesized through silver nitrate reduction by sodium citrate. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to verify the size and colloidal stability. SNP were added to acrylic resin monomer (Lucitone 550) at 0.05, 0.5 and 5 vol%. The antimicrobial effect against C. albicans (ATCC 10231) was investigated by the enumeration of colony-forming units (CFUs) and SEM. The three-point bending test was performed to analyze the flexural strength. Tissue reaction was evaluated after 7 and 60 days of implantation in the connective tissue of Wistar rats. RESULTS: Spherical particles of 5 and 10 nm were obtained. SNP at 0.05 and 0.5% incorporated into acrylic resin was effective in reducing C. albicans biofilm growth (p < .001). SEM revealed that the material was able to disrupt C. albicans biofilm formation and did not reduce the flexural strength compared to control (p > .05). The inflammatory response observed 60 days after implantation SNP in the subcutaneous tissue was similar to control. CONCLUSION: It was concluded that SNP addition at 0.05 and 0.5% into acrylic resin exhibited antimicrobial effects against C. albicans biofilm, did not interfere in the flexural strength and may be considered biocompatible.

Cytotoxicity and inflammatory response of different types of provisional restorative materials.

AIM: To evaluate the cytotoxicity and inflammatory response of different types of provisional restorative materials to mice gingival fibroblasts. METHODS: Cytotoxicity of provisional material discs (thermal-polymerized acrylic resin; auto-polymerized acrylic resin; bisacrylic resin; nano-ceramic resin for CAD/CAM and prefabricated polymer block for CAD/CAM) to Mice (Balb/c) gingival cell were investigated under direct and indirect contact (extracts) at 24, 48 and 72 h, using the MTT and Alamar blue assays. Materials extracts (24 h) were applied to the cell culture (indirect contact) or cells were seeded on discs of provisional materials, and the cytotoxicity and production of IL-6, IL-1ß and TNF-α after 24, 48 and 72 h were analyzed through MTT, Alamar Blue® and ELISA. Culture medium was used as control for indirect contact assay (extract) and the surfaces of the wells without discs of provisional materials were used as control for direct contact assay. Results were analysed statistically by ANOVA followed by the Bonferroni-Test correction. Statistically significant differences were considered if P was < .05. RESULTS: Auto-polymerized and bisacrylic resins (direct contact) reduced cell viability after 24, 48 and 72 h compared to control (P < .05). Indirect contact (extract) was not cytotoxic to cells at all periods compared to control (P > .05). Auto-polymerized and bisacrylic resins increased IL-6, IL-1ß and TNF-α levels mainly at 24 h when compared to the other materials (P < .001). CONCLUSION: Auto-polymerized and bisacrylic were more cytotoxic to mice gingival fibroblasts. CAD/CAM nano ceramic resin and prefabricated polymer blocks are more predictable materials to preserve the periodontal soft tissues.

In Vitro and In Vivo Toxicity Evaluation of Colloidal Silver Nanoparticles Used in Endodontic Treatments.

INTRODUCTION: Silver nanoparticles have been used for different purposes in dentistry, including endodontic treatments. The aim of this study was to determine the cytotoxicity of different types of silver nanoparticles on mouse fibroblast cell line L929 and the reaction of subcutaneous connective tissue of Wistar rats to these nanoparticles. METHODS: Silver nanoparticles of an average size of 5 nm were synthesized with ammonia (SNA) or polyvinylpyrrolidone (SNP). L929 was exposed to SNA and SNP (0.1-100 µg/mL), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and enzyme-linked immunosorbent assays were performed after 6, 24, and 48 hours. Culture medium was used as the control. Sixteen rats received, individually, 3 polyethylene tubes filled with a fibrin sponge embedded in 100 µL SNA or SNP (1 µg/mL). A fibrin sponge with no embedding was the control. Tissue reaction was performed qualitatively and quantitatively after 7, 15, 30, and 90 days of implantation in the dorsal connective tissue of Wistar rats. RESULTS: SNA and SNP were cytotoxic to L929 in higher concentrations, with SNA significantly more toxic than SNP. SNA and SNP did not induce significant interleukin-1ß and interleukin-6 production. The release of stem cell factor by L929 increased 48 hours after the treatment with SNP at 5 µg/mL. Histologic examination showed that the inflammatory responses caused by SNA and SNP at 1 µg/mL were similar to the control in all experimental periods. CONCLUSIONS: It was concluded that SNA and SNP were not cytotoxic at 25 µg/mL or lower concentrations. However, for safe clinical use, further studies establishing others points of its toxicologic profile are recommended.

Oral squamous cell carcinoma misdiagnosed as a denture-related traumatic ulcer: A clinical report.

A 65-year-old woman presented with an ulcerated lesion in the alveolar ridge mucosa, which appeared after new dentures had been inserted. Despite many treatment attempts, the lesion did not recede, even with the interruption of denture wearing. A biopsy was performed, and histopathologic examination revealed an ulcerated, invasive, poorly differentiated oral squamous cell carcinoma. The time from the patient's first contact with the prosthodontist because of the lesion until the appropriate diagnosis was established was approximately 6 months. This clinical report documents a significant delay in the oral squamous cell carcinoma diagnosis and treatment because of a clinical misdiagnosis of a traumatic ulcer resulting from complete dentures. Prosthodontists should be aware of the importance of early diagnosis of oral cancer among elderly prosthesis wearers.

Susceptibility of Candida albicans and Candida glabrata biofilms to silver nanoparticles in intermediate and mature development phases.

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). METHODS: 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. RESULTS: 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 48h) 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. CONCLUSIONS: 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.

Silver colloidal nanoparticle stability: influence on Candida biofilms formed on denture acrylic.

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.

Effect of smoking on the survival of dental implants.

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.

Oral health-related quality of life and satisfaction before and after treatment with complete dentures in a Dental School in Brazil.

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.

Avaliação da resposta tecidual e da citotoxicidade de soluções coloidais de nanopartículas de prata / Evaluation of tissue reaction and cytotoxicity of colloidal silver nanoparticles

O objetivo deste estudo foi investigar o efeito de diferentes soluções coloidais de nanopartículas de prata sobre a viabilidade celular de fibroblastos (linhagem L929) e sobre a resposta inflamatória de tecido subcutâneo de ratos. Nanopartículas de prata (SNP) com tamanho médio de 5 nm foram sintetizadas através da redução do nitrato de prata pelo citrato de sódio e estabilizadas com amônia (SNP-A) ou polivinilpirrolidona (SNP-P). Para avaliar a viabilidade celular, células L929 foram expostas SNP e agentes estabilizantes (amônia (NH3) e polivinilpirrolidona (PVP)) (0,1 – 100 μg/mL), e após 6, 24 e 48 h foi realizado o ensaio de citotoxicidade celular pelo método do MTT. A resposta tecidual foi realizada com tubos de polietileno contendo SNP (1.0 μg/mL; 540 μg/mL) e agentes estabilizantes (NH3 0.13 x 10-3 mol/L e PVP 0.19 g/L) implantados no tecido conjuntivo dorsal de ratos Wistar por 7, 15, 30, 60 e 90 dias. Os espécimes foram corados com hematoxilina e eosina e foram realizadas avaliações qualitativa e quantitativa. SNP inibiram a viabilidade celular no teste in vitro de maneira concentração-dependente. SNP-A foram mais tóxicas para L929 que as partículas estabilizadas com PVP. O exame histológico mostrou que SNP 540 μg/mL induziram reação tecidual significantemente mais intensa em 30 e 60 dias comparado aos grupos controles (solução fisiológica 0,9% e fibrina) nos mesmos períodos. As respostas inflamatórias causadas por SNP 1,0 μg/mL, NH3 0,13 x 10- 3 mol/L e PVP 0,19 g/L foram similares aos controles em todos os períodos experimentais. Foi possível concluir que a exposição à SNP reduziu a viabilidade de células L929 de maneira concentração-dependente. O tipo de agente estabilizante interferiu na citotoxicidade sendo SNP-A mais tóxica para L929. Ambos os tipos de soluções coloidais de nanopartículas de prata (SNP-A e SNP-P) a 540 µg/mL induziram significante resposta inflamatória no tecido subcutâneo de rato.

The aim of this study was to investigate the effect of different colloidal silver nanoparticles on cell viability of mouse fibroblasts (cell line L929) and on the subcutaneous connective tissue reaction of rats. Silver nanoparticles (SNP) of average size 5 nm were synthesized by the reduction of silver nitrate through sodium citrate and were stabilized with ammonia (SNP-A) or polyvinylpyrrolidone (SNP-P). To evaluate the cell viability, L929 cell were exposure to silver nanoparticles (0.1-100 μg/mL), and after 6, 24 and 48h MTT assay was performed. The tissue reaction was carried out with polyethylene tubes containing silver nanoparticles (1.0 μg/mL; 540 μg/mL) implanted in the dorsal connective tissue of Wistar rats for 7, 15, 30, 60, and 90 days. The specimens were stained with hematoxylin and eosin and qualitative and quantitative evaluations of the reaction were carried out. Silver nanoparticles inhibited the cell viability in the in vitro test in a concentration-dependent manner. SNP-A were more toxic to L929 than particles stabilized with polyvinylpyrrolidone (PVP). Histological examination showed that SNP at 540 μg/mL induced significant tissue reaction on 30 and 60 days after implantation compared to the controls groups (fibrin and saline 0.9%) at the same periods. The inflammatory responses caused by SNP at 1.0 μg/ml, NH3 at 0.13 x 10-3 mol/L and PVP at 0.19 g/L solutions were similar to the controls groups in all experimental periods. It was possible to conclude that SNP exposure decreased the viability of L929 cells in a concentration-dependent manner. The type of stabilizing agent interfered on the cytotoxicity of SNP being SNP-A more toxic to L929. Also, both colloidal silver nanoparticles (SNP-A and SNP-P) at 540 μg/mL induced significant inflammatory response in rat’s subcutaneous tissue.

Avaliação da resposta tecidual e da citotoxicidade de soluções coloidais de nanopartículas de prata / Evaluation of tissue reaction and cytotoxicity of colloidal silver nanoparticles

O objetivo deste estudo foi investigar o efeito de diferentes soluções coloidais de nanopartículas de prata sobre a viabilidade celular de fibroblastos (linhagem L929) e sobre a resposta inflamatória de tecido subcutâneo de ratos. Nanopartículas de prata (SNP) com tamanho médio de 5 nm foram sintetizadas através da redução do nitrato de prata pelo citrato de sódio e estabilizadas com amônia (SNP-A) ou polivinilpirrolidona (SNP-P). Para avaliar a viabilidade celular, células L929 foram expostas SNP e agentes estabilizantes (amônia (NH3) e polivinilpirrolidona (PVP)) (0,1 – 100 μg/mL), e após 6, 24 e 48 h foi realizado o ensaio de citotoxicidade celular pelo método do MTT. A resposta tecidual foi realizada com tubos de polietileno contendo SNP (1.0 μg/mL; 540 μg/mL) e agentes estabilizantes (NH3 0.13 x 10-3 mol/L e PVP 0.19 g/L) implantados no tecido conjuntivo dorsal de ratos Wistar por 7, 15, 30, 60 e 90 dias. Os espécimes foram corados com hematoxilina e eosina e foram realizadas avaliações qualitativa e quantitativa. SNP inibiram a viabilidade celular no teste in vitro de maneira concentração-dependente. SNP-A foram mais tóxicas para L929 que as partículas estabilizadas com PVP. O exame histológico mostrou que SNP 540 μg/mL induziram reação tecidual significantemente mais intensa em 30 e 60 dias comparado aos grupos controles (solução fisiológica 0,9% e fibrina) nos mesmos períodos. As respostas inflamatórias causadas por SNP 1,0 μg/mL, NH3 0,13 x 10- 3 mol/L e PVP 0,19 g/L foram similares aos controles em todos os períodos experimentais. Foi possível concluir que a exposição à SNP reduziu a viabilidade de células L929 de maneira concentração-dependente. O tipo de agente estabilizante interferiu na citotoxicidade sendo SNP-A mais tóxica para L929. Ambos os tipos de soluções coloidais de nanopartículas de prata (SNP-A e SNP-P) a 540 µg/mL induziram significante resposta inflamatória no tecido subcutâneo de rato

The aim of this study was to investigate the effect of different colloidal silver nanoparticles on cell viability of mouse fibroblasts (cell line L929) and on the subcutaneous connective tissue reaction of rats. Silver nanoparticles (SNP) of average size 5 nm were synthesized by the reduction of silver nitrate through sodium citrate and were stabilized with ammonia (SNP-A) or polyvinylpyrrolidone (SNP-P). To evaluate the cell viability, L929 cell were exposure to silver nanoparticles (0.1-100 μg/mL), and after 6, 24 and 48h MTT assay was performed. The tissue reaction was carried out with polyethylene tubes containing silver nanoparticles (1.0 μg/mL; 540 μg/mL) implanted in the dorsal connective tissue of Wistar rats for 7, 15, 30, 60, and 90 days. The specimens were stained with hematoxylin and eosin and qualitative and quantitative evaluations of the reaction were carried out. Silver nanoparticles inhibited the cell viability in the in vitro test in a concentration-dependent manner. SNP-A were more toxic to L929 than particles stabilized with polyvinylpyrrolidone (PVP). Histological examination showed that SNP at 540 μg/mL induced significant tissue reaction on 30 and 60 days after implantation compared to the controls groups (fibrin and saline 0.9%) at the same periods. The inflammatory responses caused by SNP at 1.0 μg/ml, NH3 at 0.13 x 10-3 mol/L and PVP at 0.19 g/L solutions were similar to the controls groups in all experimental periods. It was possible to conclude that SNP exposure decreased the viability of L929 cells in a concentration-dependent manner. The type of stabilizing agent interfered on the cytotoxicity of SNP being SNP-A more toxic to L929. Also, both colloidal silver nanoparticles (SNP-A and SNP-P) at 540 μg/mL induced significant inflammatory response in rat’s subcutaneous tissue

Silver distribution and release from an antimicrobial denture base resin containing silver colloidal nanoparticles.

PURPOSE: The aim of this study was to evaluate a denture base resin containing silver colloidal nanoparticles through morphological analysis to check the distribution and dispersion of these particles in the polymer and by testing the silver release in deionized water at different time periods. MATERIALS AND METHODS: A Lucitone 550 denture resin was used, and silver nanoparticles were synthesized by reduction of silver nitrate with sodium citrate. The acrylic resin was prepared in accordance with the manufacturers' instructions, and silver nanoparticle suspension was added to the acrylic resin monomer in different concentrations (0.05, 0.5, and 5 vol% silver colloidal). Controls devoid of silver nanoparticles were included. The specimens were stored in deionized water at 37°C for 7, 15, 30, 60, and 120 days, and each solution was analyzed using atomic absorption spectroscopy. RESULTS: Silver was not detected in deionized water regardless of the silver nanoparticles added to the resin and of the storage period. Micrographs showed that with lower concentrations, the distribution of silver nanoparticles was reduced, whereas their dispersion was improved in the polymer. Moreover, after 120 days of storage, nanoparticles were mainly located on the surface of the nanocomposite specimens. CONCLUSIONS: Incorporation of silver nanoparticles in the acrylic resin was evidenced. Moreover, silver was not detected by the detection limit of the atomic absorption spectrophotometer used in this study, even after 120 days of storage in deionized water. Silver nanoparticles are incorporated in the PMMA denture resin to attain an effective antimicrobial material to help control common infections involving oral mucosal tissues in complete denture wearers.

Evaluation of rat alveolar bone response to Angelus MTA or experimental light-cured mineral trioxide aggregate using fluorochromes.

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: It was concluded that both materials present a similar inflammatory response and bone healing, but dystrophic mineralization was observed only with Angelus MTA.

Complete denture hygiene and nocturnal wearing habits among patients attending the Prosthodontic Department in a Dental University in Brazil.

OBJECTIVE: The aim of this study was to evaluate the overnight wearing and cleaning habits of complete denture wearers. BACKGROUND: Successful complete denture treatment can be achieved when the patients are motivated and aware of appropriate denture wear and hygiene. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: The patients need instructions and motivation concerning denture hygienic and denture removal overnight.

Postsurgical care for rehabilitation with implant-retained extraoral prostheses.

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.

Adição de nanopartículas de prata ao Poli (metil metacrilato): análise microbiológica / Addition of silver nanoparticles to the poly (methyl methacrylate): microbiological analysis

O objetivo do presente estudo foi verificar a atividade antimicrobiana de uma resina acrílica à base de poli (metil metacrilato) (PMMA) contendo nanopartículas de prata frente ao microorganismo Candida albicans. Utilizou-se a resina acrílica termopolimerizável Lucitone 550 e as nanopartículas de prata foram sintetizadas por meio da redução dos íons prata do nitrato de prata pelo citrato de sódio. A forma e o tamanho das partículas foram confirmados por microscopia eletrônica de varredura (MEV) e de transmissão (MET), tendo-se obtido partículas na forma esférica e com tamanhos médios de 5 e 10 nm. A resina acrílica foi proporcionada de acordo com as instruções do fabricante e a solução coloidal de nanopartículas de prata foi adicionada ao componente líquido da resina acrílica nas concentrações de 0,05%, 0,5% e 5% baseadas na massa do polímero. Após o processamento, os espécimes foram esterilizados por radiação de Co-60. Foram analisados a adesão de microorganismos à superfície do poli (metil metacrilato)/prata (PMMA/Ag) e a formação de biofilme por Candida albicans sobre a superfície polimérica através de microscopia de luz e de MEV. Os resultados mostraram redução estatisticamente significante (P < 0,05) da adesão de microorganismos à superfície do nanocompósito para os grupos com 0,05 e 0,5% de nanopartículas de prata com tamanho de 5nm quando comparados ao grupo controle. A microscopia de luz nãomostrou diferença na formação de biofilme entre os grupos dos nanocompósitos e o grupo controle. A MEV sugeriu uma redução na quantidade de células na superfície dos grupos contendo nanopartículas de prata, especialmente até 12 horas de crescimento fúngico. Os resultados sugerem ação inibitória sobre a adesão e formação de biofilme por Candida albicans quando da adição de nanopartículas de prata de tamanho 5 nm à resina acrílica nas concentrações de 0,05% e 0,5%

The aim of this study was to verify the antimicrobial activity of a poly (methyl methacrylate) acrylic resin containing silver nanoparticles against Candida albicans microorganism. The heat-polymerized acrylic resin Lucitone 550 was used and the silver nanoparticles were synthesized through the reduction of silver ions of silver nitrate by sodium citrate. The shape and size of the particles were confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and showed spherical particles with medium size of 5 and 10 nm. The acrylic resin was proportioned according to the manufacturer’s instructions and the silver nanoparticles colloid solution was added to the liquid of the acrylic resin in 0.05%, 0.5% and 5% of concentration based on the polymer mass. After being processing, the specimens were sterilized by Co-60 radiation. The adhesion of cells of Candida albicans and the biofilm formation on the surface of the polymer were evaluated by light microscopy and SEM. The results demonstrated significantly reduction (P < .05) of the microorganisms adhesion on the surface of the nanocomposites for the groups containing 0.05 and 0.5% of silver nanoparticles with size of 5nm when compared to the control group. The light microscopy did not show difference in the biofilm formation among the groups evaluated. The SEM images suggested reduction of growth of Candida albicans cells for the nanocomposite groups, mainly up to the period of 12 hours. It was concluded that the addition of silver nanoparticles with size of 5 nm to the PMMA in 0.05% and 0.5% concentrations showed antimicrobial effect against Candida albicans

The growing importance of materials that prevent microbial adhesion: antimicrobial effect of medical devices containing silver.

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.