Efeito da irradiação com microondas sobre células de Candida albicans

A irradiação com microondas tem sido recomendada para a desinfecção de próteses odontológicas de resinas acrílicas devido ao seu poder inibitório sobre os microrganismos. Entretanto, as alterações celulares provocadas pela irradiação e que levam à inativação dos microrganismos presentes nas próteses não estão esclarecidas. O objetivo do presente estudo foi investigar os efeitos das microondas sobre células de Candida albicans, por meio de parâmetros de contagem celular e de liberação de substâncias intracelulares. Foram obtidas culturas de C. albicans de 24 horas em Tryptic Soy Broth (TSB) a partir de cepas padrão (ATCC 10231). As células foram centrifugadas, lavadas e ressuspensas em 400 mL de água destilada gelada na concentração de 108 cél/mL. Essa suspensão foi dividida em experimental e controle. A suspensão experimental (200 mL) foi colocada em um béquer de 500 mL contendo uma prótese total acrílica estéril e irradiada por microondas durante 6 min a 650 W. A suspensão controle não foi submetida à irradiação. Para ambas as suspensões, foram realizadas diluições seriadas para contagem celular em câmara de Neubauer, utilizando a entrada do corante azul de Metileno, como indicativo de alteração de permeabilidade de membrana. Alíquotas diluídas também foram semeadas em Agar Sabouraud Dextrose (ASD). Alíquotas não diluídas foram analisadas quanto à densidade óptica (DO) a 550 nm. Para a quantificação de substâncias liberadas, as células foram eliminadas das suspensões por centrifugação e filtragem e a solução resultante foi liofilizada. O conteúdo liofilizado foi ressuspenso em 5 mL de água destilada e analisado pelos seguintes métodos: Microprote e Sensiprote, para quantificação de proteínas; potenciometria, para quantificação de Na+ e K+; Liquiform,...Microwaves have been used in the disinfection of acrylic resin dentures as a result of its inhibitory effect on microorganisms. However, much controversy exists concerning the lethal effects of microwave radiation on microorganisms. Evaluating the presence of significant differences on cell counts and substances released between irradiated and non-irradiated Candida albicans cell suspensions was the aim of this study. A stock C. albicans strain (ATCC 10231) was cultured in 600 mL of Tryptic Soy Broth (TSB) at 37ºC on a rotating shaker. The cells were centrifuged, water-washed and resuspended in distilled cold water to a final concentration of 108 cell/mL. The cell suspensions were equally divided in a 200 mL experimental suspension, which was placed in a 500 mL beaker with an acrylic resin denture inside and irradiated for 6 min at 650 W. The control suspension (200 mL) was not submitted to irradiation. Aliquots of both suspensions were serially diluted and counting in a Neubauer chamber using the uptake of Methylene blue dye as indicative of alterations in membrane cell permeability. Serially diluted aliquots were spread on Agar Sabouraud dextrose (ASD) plates for viability assay. Non-diluted aliquots were spectrophotometrically measured at 550 nm. To quantify the intracellular released substances, the cells were separated from the suspensions by centrifugation followed by filtering, and the resulting solution was freeze-dried. This liophylized was resuspended in 5 mL of cold water and submitted to optical density (OD) analyses of protein contents by the Microprote and Sensiprote systems; potenciometry analysis of Na+ and K+ contents; Ca++ contents analysis by Liquiform; and nucleic acids contents analysis by OD measurements at 260 nm...(Complete abstract, click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Surface Roughness of Acrylic and Silicone-Based Soft Liners: In Vivo Study in a Rat Model

Purpose: The aim of this in vivo animal study was to investigate changes in the surface roughness of soft liners over time. Materials and Methods: Forty adult Wistar rats (Rattus norvergicus albinus) were fitted with acrylic custom-made palatal plates relined by dynamic impressions and tested with the following soft liners: Dentuflex (DF), Trusoft (TS), Dentusoft (DS), and Ufi Gel P (UG). Half of the animals for each tested material had the plates fitted during the material reline procedure. Their surface roughness was read immediately (IRa group, n = 5). The other half used the palatal plates for 14 days before roughness readings were performed (FRa group, n = 5). The surface roughness (Ra) of the inner surface from the relined dentures was recorded using a Surftest SJ-401 with eight readings per specimen, and mean values were obtained. Data (μm) were analyzed by two-way ANOVA and Tukey's test (α = 0.05). Results: IRa means (2.92 ± 0.87 μm) and FRa means (3.35 ± 0.65 μm) were significantly different (p = 0.016). UG showed a lower (p = 0.01) Ra mean (2.1 ± 0.52 μm) than DF (3.94 ± 0.81 μm), TS (4.12 ± 0.64 μm), and DS (3.27 ± 0.64 μm). Conclusions: Ufi Gel P showed the smoothest surface among the materials evaluated. The period of use resulted in changes in the surface roughness of the materials tested. © 2013 by the American College of Prosthodontists.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

In-office bleaching effects on the pulp flow and tooth sensitivity – case series

Laser Doppler flowmetry (LDF) is a noninvasive method capable of evaluating variations in pulp blood flow (PBF) and pulp vitality. This method has thus far not been used to assess changes in blood flow after in-office bleaching. The aim of this case series report was to measure changes in PBF by LDF in the upper central incisor of three patients submitted to in-office bleaching. The buccal surfaces of the upper arch were bleached with a single session of 35% hydrogen peroxide gel with three 15-min applications. The color was recorded using a value-oriented Vita shade guide before in-office bleaching and one week after the procedure. The tooth sensitivity (TS) in a verbal scale was reported, and PBF was assessed by LDF before, immediately, and one week after the bleaching session. The lower arch was submitted to dental bleaching but not used for data assessment. A whitening degree of 3 to 4 shade guide units was detected. All participants experienced moderate to considerable TS after the procedure. The PBF readings reduced 20% to 40% immediately after bleaching. One week post-bleaching, TS and PBF were shown to be equal to baseline values. A reversible decrease of PBF was detected immediately after bleaching, which recovered to the baseline values or showed a slight increase sooner than one week post-bleaching. The LDF method allows detection of pulp blood changes in teeth submitted to in-office bleaching, but further studies are still required

Considerações gerais sobre prótese fixa adesiva

The success rate of resin-bonded fixed partial dentures is directly related to the adhesive system and the tooth preparation design for good retention. These resin-bonded bridges represent a prosthodontic alternative, based on their costeffectiveness, conservative techniques, and ease of laboratory manufacturing. Through a thorough review of the literature, this study aimed to report on cavity designs, types of materials used, and the advantages and disadvantages of the resin-bonded fixed partial denture. One of significant advantages of the resin-bonded fixed partial dentures is the conservation of the tooth structure, whereas its main disadvantage includes aesthetic limitations, given that the alloy may in fact be visible. Preparation design, cement type, and casting alloy type, as well as surface treatment, are among the factors that influence the longevity of resin-bonded fixed partial dentures. Treatments with resin-bonded fixed partial dentures present a bright outlook regarding the conservation of tooth structures, as well as a high level of success.O sucesso das próteses fixas adesivas está diretamente relacionado ao sistema adesivo utilizado e ao tipo de preparo realizado para obtenção de uma boa retenção. Essas próteses surgiram como uma alternativa protética, tendo em vista o baixo custo, o uso de uma técnica mais conservadora e a facilidade laboratorial. Este estudo objetivou discutir, por meio de uma revisão de literatura, as formas de preparo, os tipos de materiais e as vantagens e desvantagens do uso de próteses fixas adesivas. Dentre as principais vantagens, destacase a conservação da estrutura dentária e como desvantagem, a limitação da estética devido à possibilidade do aparecimento da liga metálica. O desenho do preparo, o tipo de cimento e o tipo de liga, bem como o tratamento de superfície são alguns dos fatores que podem influenciar na longevidade do manuseio desse tipo de prótese. O tratamento com próteses fixas adesivas tem grande potencial na conservação dos dentes pilares e também um percentual significativo de sucesso

Desordens temporomandibulares em usuários de prótese parcial removível: prevalência de acordo com a classificação de Kennedy

OBJECTIVE: The aim of this study was to determine the prevalence of temporomandibular disorders in patients with removable partial dentures according to Kennedy classification. METHOD: The population consisted of patients who required care at the State University of Ponta Grossa. The patients wore complete upper and lower removable partial dentures between 1 to 5 years. The patients were divided into five groups (n = 15): G1: wearer of complete maxillary denture opposed by a Class I (Kennedy) removable partial denture; G2: wearer of complete maxillary denture opposed by a Class II (Kennedy) removable partial denture; G3: wearer of complete maxillary denture opposed by a Class III (Kennedy) removable partial denture; G4: wearer of complete maxillary denture opposed by a Class IV (Kennedy) removable partial denture and G5: fully dentate patients (control group). Fonseca's questionnaire was applied to verify the level of TMD. The qui-square test (α = .05) was used to analyze association between the variables. RESULT: No statistical difference (P > 0.05) was found among groups. All groups showed mild or moderate TMD. CONCLUSION: The findings from this clinical study showed that the presence of TMD in wearers of removable partial denture could not be correlated to the classification of Kennedy, since the presence of TMD for edentulous patients and dentate patients appeared similar.OBJETIVO: O objetivo deste estudo foi determinar a prevalência das desordens temporomandibulares em pacientes com prótese parcial removível, de acordo com a classificação de Kennedy. MÉTODO: A população estudada consistiu de pacientes que procuraram tratamento na Universidade Estadual de Ponta Grossa. Os pacientes selecionados eram usuários de prótese total superior e prótese parcial removível inferior, e esse uso, à época do estudo, fazia entre 1 e 5 anos. Os pacientes foram divididos em cinco grupos (n = 15): G1: usuários de prótese total superior e prótese parcial removível inferior Classe I (Kennedy); G2: usuários de prótese total superior e prótese parcial removível inferior Classe II (Kennedy); G3: usuários de prótese total superior e prótese parcial removível inferior Classe III (Kennedy); G4: usuários de prótese total superior e prótese parcial removível inferior Classe IV (Kennedy), e G5: pacientes totalmente dentados (grupo controle). O questionário de Fonseca foi aplicado para verificar o grau de DTM. O teste qui-quadrado (α = 0,05) foi usado para avaliar a associação entre as variáveis. RESULTADO: Nenhuma diferença estatística (P > 0,05) foi encontrada entre os grupos. Em todos os grupos, os pacientes apresentaram DTM leve ou moderada. CONCLUSÃO: Os resultados deste estudo clínico mostraram que a presença de DTM em pacientes usuários de prótese não pôde ser correlacionada ao uso de prótese, já que a presença de DTM para pacientes desdentados e dentados apresentou-se semelhante.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Evaluation of different treatment methods against denture stomatitis: a randomized clinical study

Objective. The aim of this clinical study was to determine the efficacy of Uncaria tomentosa (cat's claw) against denture stomatitis (DS).Study Design. Fifty patients with DS were randomly assigned into 3 groups to receive 2% miconazole, placebo, or 2% U tomentosa gel. DS level was recorded immediately, after 1 week of treatment, and 1 week after treatment. The clinical effectiveness of each treatment was measured using Newton's criteria. Mycologic samples from palatal mucosa and prosthesis were obtained to determinate colony forming units per milliliter (CFU/mL) and fungal identification at each evaluation period.Results. Candida species were identified with HiCrome Candida and API 20C AUX biochemical test. DS severity decreased in all groups (P .05). C albicans was the most prevalent microorganism before treatment, followed by C tropicalis, C glabrata, and C krusei, regardless of the group and time evaluated. U tomentosa gel had the same effect as 2% miconazole gel.Conclusions. U tomentosa gel is an effective topical adjuvant treatment for denture stomatitis

Effect of potentially chromogenic beverages on shear bond strength of acrylic denture teeth to heat-polymerized denture base resins

Background: Detachment of denture acrylic resin artificial teeth from denture base resin is one of the most common problems presented by denture wearers. Purpose: This study investigated the shear bond strength (SBS) and fracture type of bonding interface of two commercial acrylic teeth (Vipi Dent Plus e Biolux) to two denture base resins (Vipi Cril e Lucitone 550) after immersion in potentially chromogenic beverages (coffee, cola soft drink, and red wine) or control solution (distilled water). Materials and Methods: Maxillary central incisor acrylic teeth were placed at 45° to denture base resin and submitted to short polymerization cycle according to manufacturers. Specimens were divided according to the combination tooth/resin/solution (n = 8) and submitted to bond strength tests in a universal testing machine MTS-810 (0.5 mm/min). Subsequently, fracture area was analyzed by stereomicroscope at a magnification of ×10 and categorized into adhesive, cohesive, or mixed failure. Results: The bond strength of teeth/denture base resins interface was not significantly affected by tested solutions (P > 0.087), except for Biolux teeth immersed in coffee (P < 0.01). In all conditions, the Vipi Dent Plus teeth showed higher bond strength to Lucitone and Vipi Cril resins when compared to Biolux teeth (P < 0.003). All specimens' failure modes were cohesive. Conclusions: The SBS of acrylic teeth to denture base resins was not generally influenced by immersion in the tested staining beverages

Colour stability of acrylic resin denture teeth after immersion in different beverages

The colour stability of acrylic resin denture teeth in beverages was investigated. A spectrophotometer measured the colour (CIE-L*a*b* system) of all specimens after storage in distilled water for 24 h at 37°C (T0). Specimens were then immersed in various beverages. After 15 days (T1) and 30 days (T2), for each material, the mean ∆E values were calculated and compared by two-way ANOVA and Tukey intervals (α=0.05). In the ∆T0T1 period, specimens stored in red wine were significantly discoloured, compared to distilled water (P=0.003). There was no difference between immersion solutions in ∆ET0T2 (P=0.772) and in ∆ET1T2 (P=0.058), and no difference between materials in all immersion periods