Does the Incorporation of Graphene Oxide into PMMA Influence its Antimicrobial Activity?

INTRODUCTION: The increase in infectious diseases mediated by oral bacteria has been one of the most potent threats to human health, specifically to the elderly. Researchers seek to incorporate antimicrobial nanomaterials into PMMA to control the colonization of microorganisms and reduce deadly diseases. OBJECTIVE: To conduct a systematic review to answer the question: "Does graphene oxide incorporated into polymethylmethacrylate influence its antimicrobial activity?" METHODS: The electronic search was performed in PubMed, Embase, Web of Science, Scopus, and Google Scholar databases, and articles published until October 2021 were selected. The search terms were: ("acrylic resin" OR PMMA) AND (graphene OR "oxide graphene") AND (antimicrobial OR antibacterial OR "anti-infective agent"). The risk of bias analysis of the articles was performed using the quasi-experimental study assessment tool adapted from the JBI. RESULTS: Two hundred and fifty-nine articles were found in the databases. After removing the duplicates, 245 were analyzed by title and abstract. Of these, 06 were selected for full reading, of which 03 met the eligibility criteria and were included in this systematic review. CONCLUSION: This systematic review's findings can infer that the incorporation of graphene in the form of graphene-based coatings to PMMA showed antimicrobial effectiveness.

Denture Adhesives Associated with Silver Vanadate: Antimicrobial Approach Against Multi- Species Biofilms on Acrylic Resin Surfaces.

Alternatives have been sought to add an antimicrobial property to denture adhesives. This study evaluated the antimicrobial potential of adhesives associated with nanostructured silver vanadate decorated with silver nanoparticles (ß-AgVO3). Specimens in acrylic resin were treated with the adhesives associated with ß-AgVO3 (1%, 2.5%, 5% and 10%). As control, specimens treated only with Ultra Corega Cream (UCC) or Ultra Corega Powder (UCP) adhesive were used. Multispecies biofilm of Candida albicans, Candida glabrata, Streptococcus mutans and Staphylococcus aureus was evaluated by counting colony forming units per milliliter (CFU/mL), colorimetric assay and fluorescence microscopy. The data were analyzed using the two-way analysis of variance (ANOVA) and Bonferroni multiple comparisons test (α=0.05). For both adhesives, a small amount of ß-AgVO3 (1%) completely inhibited S. mutans (P⟨0.05). For the other microorganisms, there was a reduction in metabolic activity and complete inhibition in the groups with intermediate or greater amounts of nanomaterial (P⟨0.05), except for C. albicans, which was reduced (P⟨0.05) but not completely inhibited in UCP. Microscopy that showed less biofilm in the groups with ß-AgVO3 and in the UCC than UCP. Denture adhesives in powder and cream form with ß-AgVO3 showed potential antimicrobial activity against multispecies biofilm. Powder adhesive showed higher biofilm formation.

Zirconia Implants Produced by Additive Manufacturing - A Scoping Review.

INTRODUCTION: Additive manufacturing is a tool with potential use in medicine and dentistry. The manufacture of metals and composites is already advanced, however, concerns about titanium hypersensitivity, tissue staining, and corrosion caused by gradual material degradation encourage research into more biocompatible alternatives. OBJECTIVE: This systematic scoping review aimed to gather studies that evaluated zirconia implants produced by additive manufacturing to describe the current stage of the printing technique and the final product. METHODS: Searches in Embase, PubMed, SCOPUS, Web of Science, and Google Scholar databases were enriched with manual searches between February and March 2021 and updated in June 2022 using keywords: zirconium implants, zirconium oxide, additive manufacturing, rapid prototyping, 3D printing, selective laser melting, and electron beam melting. The criteria included studies that evaluated or described zirconia implants obtained by 3D printing, with a direct relationship to dentistry or orthopedics. RESULTS: The database search resulted in 671 articles. Eight articles were selected for full reading and remained in this systematic review. CONCLUSION: The printing technique for zirconia implants is promising. However, further studies are required before implants produced by the printing technique can be tested clinically. The literature with results regarding the impression product is still limited.

Factors that Affect the Shear Bond Strength of Pit and Fissure Sealants to Tooth Structure: A Systematic Review.

INTRODUCTION: Pit and fissure sealants are effective in preventing caries disease, however, they may present flaws that damage the physical barrier leading to treatment failure. OBJECTIVE: To answer the question ''Do pit and fissure sealants present good adhering to the dental structure when analyzed by their resistance to shear/microshear?". METHODS: This systematic review followed the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) and was recorded in Open Science Framework. Embase, PubMed, SCOPUS, and Web of Science databases were used for the search strategy. The articles were selected according to the eligibility criteria. The risk of bias was performed with the adaptation of the quasi-experimental studies tool by Joanna Briggs Institute (JBI). RESULTS: 1245 studies were found in the databases when applying the search strategy, after removal of duplicates 881 were evaluated and 44 were selected. After applying the JBI tool, 30 studies presented low risk and 15 moderate risk of bias. Meta-analysis was not possible to performed due to the heterogeneity of the studies. CONCLUSION: The adhesion is dependent on the application protocol, and among the protocols evaluated, conditioning with 37% phosphoric acid for 60 seconds and contamination of the substrate, as these can affect sealant adhesion.

Prevention of Caries in Cancer Patients: A Systematic Review on the Effectiveness of Dental Materials.

This study aims to identify dental materials and their effectiveness in preventing caries in patients after chemotherapy and radiotherapy for the head and neck. The electronic search was performed in PubMed, Science Direct, Embase and Scopus. All 653 articles found passed through a double-blinded screening process. The exclusion of articles by reading titles and abstracts selected 16 articles for full reading, of which 4 were included into the study. A risk of bias analysis for non-randomized and randomized articles was performed using respectively the ROBINS I and ROB II tools. The data extraction suggested that the casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), in association with fluorine, is able to form harder surfaces compared to the control group, the intraoral fluoride-releasing system (IFRS) effectiveness is similar to the fluorine in gel and a mouthwash composed of natural enzymes (Oral7) did not demonstrate effectiveness in the prevention dental caries. New randomized controlled clinical trials are necessary to evaluate the effectiveness of prevention when applying dental materials in patients after treatment of head and neck cancer.

Surface Characteristics and Microbial Adhesion in Polymethylmethacrylate for Denture Base Submitted to Antimicrobial Agents and Cleaning Agents: A Systematic Review.

This review aimed to identify the influence of antimicrobial and cleaning agents on surface characteristics such as surface free energy (SFE) and wettability, and microbial adhesion in polymethylmethacrylate (PMMA) for denture base. The review question, based on PICO, was: "Does intervention with antimicrobial and cleaning agents in PMMA influence the surface free energy, wettability, and consequently the microbial adhesion?" and the protocol was registered in Open Science Framework (osf. io/v3xgn). The search was performed in PubMed, Lilacs, Embase, Scopus, and Science Direct databases, using the terms: ("acrylic resin" OR PMMA) AND (antimicrobial OR antibacterial) AND ("electrostatic interaction" OR surface free energy) AND (biofilm OR "bacteria adhesion"), and resulted in 462 articles, of which 7 were included. The antimicrobials polypara-xylylene, carboxybetaine methacrylate, ethylene glycol methacrylate phosphate, and deposition of F and Ag ions in PMMA influenced the SFE and wettability. Denture cleaners reduced microbial adhesion. Five of the included studies evaluated the microbial adhesion, however, only two observed a direct relationship between SFE, wettability, and microbial adhesion. It was concluded that the intervention with antimicrobial and cleaning agents in PMMA can interfere in SFE and surface wettability, but no correlation was observed between microbial adhesion and these surface characteristics in PMMA.

Short-term post-operative pain and discomfort following insertion of mini-implants for retaining mandibular overdentures: a randomized controlled trial.

The retention of removable dentures by mini-implants is a relatively recent treatment modality and may lead to minimal post-operative trauma. This study compared post-operative pain and discomfort following the insertion of mini-implants (two or four) or two standard-size implants for the retention of mandibular overdentures. One hundred and twenty edentulous participants (mean age 59.5 ± 8.5 years) were randomly allocated into three groups according to received treatment: (GI) four mini-implants, (GII) two mini-implants or (GIII) two standard implants. Seven days after implant insertion, patients answered questions (100-mm VAS) relating to pain, swelling, and discomfort with chewing, speech and hygiene, considering their experiences during the 1st and 6th day. Groups were compared by two-way anova (α = 0.05). All participants (GI: 38; GII: 42; GIII: 40) were analysed after 7 days. At the 6th day, GI felt significantly higher pain than GII and GIII. GI also reported more difficulty in performing oral hygiene practices than GIII during the 1st day. There was no significant difference between groups for the other questions and periods. No participant suffered unexpected side effects. The use of four mini-implants induces more intense post-operative pain at the 6th day than the insertion of two mini- or conventional fixtures, as well as more difficult oral hygiene on the 1st day. Clinicaltrials.gov, NCT01411683; FAPESP, 2011/00688-7 and 2011/23347-0.

Assessment of surface hardness of acrylic resins submitted to accelerated artificial aging.

AIM: The aim of this study was to assess the influence of accelerated artificial aging (AAA) on the surface hardness of acrylic resins. METHODS: The following three commercial brands of acrylic resins were tested: Vipi Flash (autopolymerized resin), Vipi Wave (microwave heat-polymerized resin) and Vipi Cril (conventional heat-polymerized resin). To perform the tests, 21 test specimens (65x10x3 mm) were made, 7 for each resin. Three surface hardness readings were performed for each test specimen, before and after AAA, and the means were submitted to the following tests: Kolmogorov-Smirnov (P>0.05), Levene Statistic, Two-way ANOVA, Tukey Post Hoc (P<0.05) with the SPSS Statistical Software 17.0. RESULTS: The analysis of the factors showed significant differences in the hardness values (P<0.05). Before aging, the autopolymerized acrylic resin Vipi Flash showed lower hardness values when compared with the heat-polymerized resin Vipi Cril (P=0.001). After aging, the 3 materials showed similar performance when compared among them. The Vipi Cril was the only one affected by AAA and showed lower hardness values after this procedure (Pp=0.003). CONCLUSION: It may be concluded that accelerated artificial aging influenced surface hardness of heat-polymerized acrylic resin Vipi Cril.

Malignant pilomatricoma in a dog.

An 11-year-old female German shepherd dog was presented with a history of lameness and pain in the left forelimb. Clinical examination revealed ataxia of the hindlimbs and a subcutaneous mass in the left prescapular region. Radiography revealed metastatic foci in the left humerus, lung and abdomen. Gross necropsy examination revealed a firm, white mass in the left prescapular region. Multiple nodules with similar characteristics were observed in the lung, liver and spleen. Bone lysis was noted in the humerus and the fifth to seventh lumbar vertebrae. Microscopical examination revealed a proliferation of basal cells forming irregular islands of various sizes and surrounding extensive zones of keratinized 'ghost' cells. A definitive diagnosis of malignant pilomatricoma was made. This is a rare tumour in dogs with no previous report of metastasis to the spleen and liver.

Cutaneous myxosarcoma with pulmonary metastases in a dog.

The pathological findings in a 13-year-old dog with cutaneous myxosarcoma with pulmonary metastases are described. Grossly, there was a large subcutaneous mass in the right scapular region, a smaller nodule in the caudal abdominal region and a fibrotic mass at a fracture site in the right hindlimb. Radiographic examination revealed several pulmonary nodules. Microscopical evaluation revealed a myxosarcoma characterized by the proliferation of spindle to stellate cells with multiple prominent nucleoli and vascular invasion. The neoplastic cells were haphazardly arranged in a mucopolysaccharide matrix. Immunohistochemically, the neoplastic cells expressed vimentin, but not cytokeratin or glial fibrillary acidic protein. There was restricted expression of desmin, smooth muscle actin and S-100 protein.

Measurement of the D(s)+ lifetime.

A high statistics measurement of the D(s)+ lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis of the two decay modes, D(s)+ --> phi(1020)pi+ and D(s)+ -->K*(892)0K+, used for the measurement. The measured lifetime is 507.4 +/- 5.5(stat) +/- 5.1(syst) fs using 8961 +/- 105 D(s)+ --> phi(1020)pi+ and 4680 +/- 90 D(s)+ --> K*(892)0K+ decays. This is a significant improvement over the present world average.

A high statistics measurement of the Lambda(+)(c) lifetime.

A high statistics measurement of the Lambda(+)(c) lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat) +/- 2.5 (syst) fs from 8034 +/- 122 Lambda(+)(c)-->pK(-)pi(+) decays represents a significant improvement over the present world average.

Search for CP violation in the decays D+--> K(S)pi+ and D+-->K(S)K+.

A high-statistics sample of photoproduced charm from the FOCUS experiment has been used to search for direct CP violation in the decay rates for D+-->K(S)pi+ and D+-->K(S)K+. We have measured the following asymmetry parameters relative to D+-->K-pi+pi+: A(CP)(K(S)pi+) = (-1.6+/-1.5+/-0.9)%, A(CP)(K(S)K+) = (+6.9+/-6.0+/-1.5)%, and A(CP)(K(S)K+) = (+7.1+/-6.1+/-1.2)% relative to D+-->K(S)pi+. We have also measured the relative branching ratios and found Gamma(D+-->K(0)pi+)/Gamma(D+-->K-pi+pi+) = (30.60+/-0.46+/-0.32)%, Gamma(D+-->K(0)K+)/Gamma(D+-->K-pi+pi+) = (6.04+/-0.35+/-0.30)%, and Gamma(D+-->K(0)K+)/Gamma(D+-->K(0)pi+) = (19.96+/-1.19+/-0.96)%.

Measurement of the branching ratios of D(+) and D(+)(s) hadronic decays to four-body final states containing a K(S).

We have studied hadronic four-body decays of D(+) and D(+)(s) mesons with a K(S) in the final state using data recorded during the 1996-1997 fixed-target run of the Fermilab high energy photoproduction experiment FOCUS. We report a new branching ratio measurement of gamma(D(+)-->K(S)K-pi(+)pi(+))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0768+/-0.0041+/-0.0032. We make the first observation of three new decay modes with branching ratios gamma(D(+)-->K(S)K+pi(+)pi(-))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0562+/-0.0039+/-0.0040, gamma(D(+)-->K(S)K+K-pi(+))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0077+/-0.0015+/-0.0009, and gamma(D(+)(s)-->K(S)K+pi(+)pi(-))/gamma(D(+)(s)-->K(S)K-pi(+)pi(+)) = 0.586+/-0.052+/-0.043, where in each case the first error is statistical and the second error is systematic.

Study of the decay D0 --> K+pi-.

Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay D0-->K+pi- with a signal yield of 149+/-31 events compared to a similarly cut sample consisting of 36 760+/-195 D0-->K-pi+ events. We use the observed ratio of D0-->K+pi- to D0-->K-pi+ (0.404+/-0.085+/-0.025)% to obtain a relationship between the D0 mixing and doubly Cabibbo suppressed decay parameters.

Differential trends in mortality from AIDS in men and women in Brazil (1984-1995).

OBJECTIVE: To analyse trends in AIDS mortality in men and women in Brazil, for the period 1984-1995. DESIGN AND METHODS: National statistics on yearly numbers of reported deaths by cause, in conjunction with census population counts and inter-censory estimates, were used to calculate age- and sex-specific AIDS mortality rates for Brazil as a whole and for São Paulo and Rio de Janeiro, the two largest cities in Brazil, and those most affected by the AIDS epidemic to date. RESULTS: Numbers of reported deaths from AIDS have increased yearly in Brazil since 1984, to approximately 15,000 in 1995. The data suggest that after a very dramatic rise in mortality rates, the epidemic may have started to slow even before the introduction of freely available highly-active anti-retroviral therapy, although unequally in terms of both geographical and sex distributions. Women also tended to die at relatively younger ages than men in all areas studied, and by 1995 the impact of AIDS on overall mortality was practically the same for men and women aged 25-34 years (21% in São Paulo). CONCLUSIONS: Trends in mortality from AIDS in Brazil reflect both the geographical expansion of the epidemic outwards from its original epicentres, and the fact that women are becoming increasingly affected by the AIDS epidemic.

[Canine tuberculosis and its importance in public health]. / Tuberculose canina e sua importância em saúde pública.

The present paper describes tuberculosis in a family whose dog also presented the disease. The importance of animal epidemiological investigation in cases of tuberculosis in man is discussed.