Letícia Machado Gonçalves

Avaliação clínica das lesões orais associadas a doenças dermatológicas

FUNDAMENTOS: As doencas dermatologicas nao estao representadas apenas pelas lesoes que afetam a pele, mas, tambem, por manifestacoes que podem envolver as mucosas, inclusive a mucosa oral. OBJETIVOS: Avaliar a frequencia das manifestacoes orais em pacientes com doencas dermatologicas, considerando-se a localizacao e as caracteristicas clinicas das lesoes encontradas, o sexo, a idade e a raca dos acometidos. METODOS: Estudo observacional, do tipo transversal, com pacientes que procuraram atendimento no Servico de Dermatologia do Hospital Universitario Presidente Dutra (HUPD) da Universidade Federal do Maranhao (UFMA) entre outubro de 2007 e outubro de 2008 (n=88). RESULTADOS: A idade variou entre cinco e 88 anos, e o sexo feminino foi o mais atingido (2:1). Dos casos examinados, 35% eram de liquen plano, 33% de lupus eritematoso, 24% de eritema multiforme, 7% de penfigo vulgar e 1% do grupo penfigoide. As lesoes orais foram mais frequentes nos portadores de liquen plano (51%) e lupus eritematoso (20%). O liquen plano reticular foi a forma clinica mais comum e a mucosa jugal, o sitio mais acometido. CONCLUSOES: O conhecimento dessas patologias pelo cirurgiao-dentista e de fundamental importância, cabendo-lhe uma parcela de responsabilidade pelo diagnostico precoce e orientacao para o tratamento adequado. Alem disso, o exame intraoral deve ser incorporado como pratica de rotina durante o atendimento dermatologico.

Effects of Undecylenic Acid Released from Denture Liner on Candida Biofilms

Denture liners (DL) are easily colonized by Candida spp. In an attempt to prevent biofilm colonization, manufacturers have incorporated undecylenic acid (UDA) into DL. In this in vitro study, the effects of UDA released from DL on Candida biofilms were investigated. The concentrations of UDA released from commercial DL were determined by gas chromatography–mass spectrometry (GC-MS). Minimum inhibitory concentration (MIC) and minimum fungistatic concentration (MFC) tests were performed for C. albicans or C. glabrata, with UDA for comparison with the concentrations released from DL. Specimens of DL with (experimental group) and without UDA (control group) were fabricated, and Candida biofilms were developed on DL surfaces. Biofilms were evaluated by cell counts, metabolic activity, structure, and secretion of proteinase or phospholipase. The concentrations of UDA released were within the MIC and MFC ranges. In the presence of UDA, C. albicans biofilms were thinner and had lower numbers of viable and active cells, although no significant enzymatic changes were observed relative to the control group (p > 0.05). In contrast, C. glabrata biofilms exhibited higher cell counts and greater metabolic activity and also increased proteinase activity in the presence of UDA relative to the control group (p < 0.05). Overall, UDA did not prevent Candida biofilm formation.

Dietary Carbohydrates Modulate Candida albicans Biofilm Development on the Denture Surface

The purpose of this study was to investigate whether dietary carbohydrates can modulate the development of Candida albicans biofilms on the denture material surface. Poly (methyl methacrylate) acrylic resin discs were fabricated and had their surface roughness measured. Biofilms of C. albicans ATCC 90028 were developed on saliva-coated specimens in culture medium without (control) or with carbohydrate supplementation by starch, starch+sucrose, glucose, or sucrose for 72 h. The cell count, metabolic activity, biovolume, average thickness, and roughness coefficient were evaluated at the adhesion phase (1.5 h) and after 24, 48, and 72 h. The secretion of proteinases and phospholipases, cell surface energy, and production of extra/intracellular polysaccharides were analyzed after 72 h of biofilm development. Data were analyzed by one- and two-way ANOVA followed by Tukey’s test at 5% significance level. In the early stages of colonization (adhesion and 24 h), the glucose group showed the highest cell counts and metabolic activity among the groups (p<0.05). After maturation (48 and 72 h), biofilms exposed to glucose, sucrose, or starch+sucrose showed higher cell counts and metabolic activity than the control and starch groups (p<0.001). Compared to the control group, biofilms developed on starch or starch+sucrose had more proteinase activity (p<0.001), whereas biofilms developed on glucose or sucrose had more phospholipase activity (p<0.05). Exposure to starch+sucrose increased the production of extracellular and intracellular polysaccharides (p<0.05). Biofilms developed on starch or without carbohydrate supplementation presented cells with more hydrophobic behavior compared to the other groups. Confocal images showed hyphae forms on biofilms exposed to starch or starch+sucrose. Within the conditions studied, it can be concluded that dietary carbohydrates can modulate biofilm development on the denture surface by affecting virulence factors and structural features.

Thermal behavior of direct resin composites: glass transition temperature and initial degradation analyses

Purpose: The association of direct resin composites with simple thermal treatments may improve the mechanical properties of these materials. However, the ideal temperature for heat application depends on the thermal behavior of each material, such as glass transition (Tg) and initial degradation temperatures. To propose a heat treatment methodology, this study evaluated the thermal behavior of five commercial direct resin composites using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Methods: Photo-irradiation was achieved in cylindrical specimens (3 x 2 mm) using a photo-activator source (600 mW/cm² for 40 s). Thermal analyses were performed by DSC and TGA using a temperature range from 25 °C to 900 °C. Results: Tg values obtained by DSC were 130.6 °C for FillMagic, 129 oC for Glacier, 143.5 oC for Te-Econom, 147.5 °C for Prisma APH and 143.7 oC for Natural Look. A moderate weight loss began at around 270 oC for all materials, which represented the initial degradation temperature. Conclusion: Regarding the heat treatment itself, it was concluded that the effective temperature for heat treatment is material dependent.

Environmental pH influences Candida albicans biofilms regarding its structure, virulence and susceptibility to fluconazole.

Candida albicans colonizes sites with different environmental pH. However, it is unclear how these conditions can interfere on biofilms. This study aimed to evaluate the influence of environmental pH on behavior of C. albicans regarding its structure, virulence and susceptibility to fluconazole (FLZ). Minimal inhibitory concentration, minimal fungicidal concentration and time kill were used to evaluate the susceptibility to FLZ in planktonic cells under three pH values (4.0, 5.5, 7.0). These pH values were used for biofilms analysis. C. albicans ATCC 90028 was developed on poly(methlymethacrylate) resin for 48 h. Then, 2.56 μg/mL of FLZ was added to experimental groups for 24 h, and biofilms were analyzed by cell quantification, bioactivity, secretion of proteinases and phospholipases and structure. All data were analyzed by two-way ANOVA, followed by Tukeys test (α = 0.05). For planktonic cells, changes in environmental pH decreased the susceptibility to FLZ. C. albicans biofilms developed at pH 5.5 showed higher cell counts, bioactivity, bio-volume, average thickness and roughness coefficient (p < 0.05). In contrast, the presence of FLZ at pH 4.0 did not influence the structural parameters (p > 0.05), but increased secretion of proteinase and phospholipase (p < 0.05). Within the conditions studied, it was shown that environmental pH modulates the structure, virulence and susceptibility of C. albicans to FLZ.

Denture adhesives improve mastication in denture wearers.

PURPOSE This clinical trial evaluated the influence of denture adhesive (DA) use on masticatory function in denture wearers according to their denture-bearing ridge status. MATERIALS AND METHODS Thirty edentulous subjects, wearing new well-fitting dentures, were classified as having either a normal or resorbed ridge. Mastication was evaluated in patients who completed chewing tests with and without two DA substances (cream or strips), which were randomly assigned. A chewing test with a sieve method analyzed masticatory performance. A kinesiographic device evaluated chewing cycle, and a visual analog scale measured masticatory ability. Data were submitted to Mauchlys sphericity test, and PROC MIXED procedures were conducted on repeated measures. Tukey-Kramer tests performed appropriate statistical comparisons (P ≤ .05). RESULTS DA use increased masticatory performance and ability in patients with both ridge types (P < .05). Subjects with resorbed ridges showed the best masticatory performance (P < .001) and lowest chewing cycle time (P < .001) with DA cream, followed by DA strips and the nonadhesive trial. For normal ridge subjects, decreases in ×50 values were only significant with DA use (P < .05), regardless of DA type. The denture-bearing ridge status alone did not alter masticatory function in any of the parameters evaluated. CONCLUSION DAs improve mastication by shortening the chewing cycle and by enhancing chewing ability and performance.

Prevalence of temporomandibular disorders in postmenopausal women and relationship with pain and HRT

The prevalence of temporomandibular disorders (TMD) is higher in females, reaching their high peak during reproductive years, probably because of the action of some female hormones, which alter pain threshold. This study aimed to investigate the prevalence of TMD in postmenopausal women and its relationship with pain and hormone replacement therapy (HRT). In total, 284 patients were evaluated and classified using the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Pain was measured using the Visual Analogue Scale (VAS), and patients were also asked about the use of HRT. All data was analyzed using analysis of variance (ANOVA) and chi-square test. In total, 155 subjects did not have TMD and 129 had TMD; TMD group patients were classified according to RDC/TMD axis I classification as follows: muscle disorder group (1.6%), disk displacement group (72.87%), and arthralgia, osteoarthritis, and osteoarthrosis group (37.98%). Pain was registered in 35 patients who belonged to the TMD group, while 48 patients reported the use of HRT. There was a similar percentage of TMD and non TMD patients; moreover, the use of exogenous hormones was no associated with TMD, suggesting that there is no influence on the pain threshold.

Exopolysaccharide matrix of developed candida albicans biofilms after exposure to antifungal agents

This study aimed to evaluate the effects of fluconazole or nystatin exposure on developed Candida albicans biofilms regarding their exopolysaccharide matrix. The minimal inhibitory concentration (MIC) against fluconazole or nystatin was determined for C. albicans reference strain (ATCC 90028). Poly(methlymethacrylate) resin (PMMA) specimens were fabricated according to the manufacturers instructions and had their surface roughness measured. Biofilms were developed on specimens surfaces for 48 h and after that were exposed during 24 h to fluconazole or nystatin prepared in a medium at MIC, 10 x MIC or 100 x MIC. Metabolic activity was evaluated using an XTT assay. Production of soluble and insoluble exopolysaccharide and intracellular polysaccharides was evaluated by the phenol-sulfuric method. Confocal laser scanning microscope was used to evaluate biofilm architecture and percentage of dead/live cells. Data were analyzed statistically by ANOVA and Tukeys test at 5% significance level. The presence of fluconazole or nystatin at concentrations higher than MIC results in a great reduction of metabolic activity (p<0.001). At MIC or 10 x MIC, fluconazole showed high amounts of intracellular polysaccharides (p<0.05), but did not affect the exopolysaccharide matrix (p>0.05). The exposure to nystatin also did not alter the exopolysaccharide matrix at all the tested concentrations (p>0.05). Biofilm architecture was not affected by either of the antifungal agents (p>0.05). Nystatin promoted higher proportion of dead cells (p<0.05). It may be concluded that fluconazole and nystatin above the MIC concentration reduced the metabolic activity of C. albicans biofilms; however, they were not able to alter the exopolysaccharide matrix and biofilm architecture.

Confocal analysis of the exopolysaccharide matrix of Candida albicans biofilms

AIM Confocal laser-scanning microscopy (CLSM) was carried out to investigate the exopolysaccharide matrix of Candida albicans (C. albicans) biofilms developed on denture material under dietary carbohydrate exposure. METHODS Biofilms were developed on poly(methyl methacrylate) discs in culture media without (control) or with supplementation by glucose or sucrose for 72 h. For the CLSM analysis, biofilms were labeled with concanavalin A (ConA) during its development. Afterwards, biofilms were also labeled with SYTO-9. To confirm the results, the matrix was investigated by the phenol-sulfuric method. Data were analyzed by anova, followed by Tukeys test, with the level of significance set at 5%. RESULTS The use of ConA during biofilm development provided effective labeling of the exopolysaccharide matrix. The exposure to sucrose resulted in biofilms with the highest exopolysaccharide matrix biovolume (P < 0.05). The characterization obtained by CLSM was confirmed by the phenol-sulfuric method. CONCLUSION Confocal laser-scanning microscopy was found to be an effective tool for investigating the exopolysaccharide matrix of C. albicans biofilms, and exposure to sucrose resulted in increased matrix production.

Multidisciplinary Therapy of Extensive Oligodontia: A Case Report

Oligodontia is a rare congenital disorder consisting in the absence of six or more teeth. This case report describes a multidisciplinary treatment approach for a 12-year-old male with absence of 11 permanent teeth. Prior to any procedure, all primary teeth were scheduled for extraction due to poor crown-to-root ratio. The treatment plan comprised two phases: 1. orthodontic and speech therapy aimed at overbite and anterior open bite adjustment, as well as tongue position improvement; and 2. prosthetic treatment by insertion of removable temporary partial dentures. The multidisciplinary treatment involving orthodontics, speech and prosthetic therapies have reestablished the masticatory function and aesthetics, allowing the patient to achieve greater self-esteem and better social acceptance.