Changes in roughness of denture base and reline materials by chemical disinfection or microwave irradiation: Surface roughness of denture base and reline materials

OBJECTIVE: The effect of disinfection by immersion in sodium perborate solution and microwave irradiation on surface roughness of one denture base resin (Lucitone 550 -L), 3 hard chairside reline resins (Tokuyama Rebase II-TR, New Truliner-NT, Ufi Gel hard-UH) and 3 resilient reline materials (Trusoft-T; Sofreliner-S, Dentusil-D) was evaluated. MATERIAL AND METHODS: Thirty specimens of each material were made and divided into 3 groups: Control - not disinfected; P - daily disinfection by immersing in sodium perborate solution (3.8%); MW - microwave disinfection (6 min/650 W). Roughness measurements were made after polymerization (baseline) and after 1, 3 and 28 days. Roughness differences relative to the baseline readings were analyzed by Student's t-test (P=0.05). RESULTS: At baseline, Trusoft showed the highest (

Efeito de tratamentos térmicos após a polimerização sobre a citotoxicidade de duas resinas acrílicas para base de próteses

INTRODUCTION: Most denture base acrylic resins have polymethylmethacrylate in their composition. Several authors have discussed the polymerization process involved in converting monomer into polymer because adequate polymerization is a crucial factor in optimizing the physical properties and biocompatibility of denture base acrylic resins. To ensure the safety of these materials, in vitro cytotoxicity assays have been developed as preliminary screening tests to evaluate material biocompatibility. ³H-thymidine incorporation test, which measures the number of cells synthesizing DNA, is one of the biological assays suggested for cytotoxicity testing. AIM: The purpose of this study was to investigate, using ³H-thymidine incorporation test, the effect of microwave and water-bath post-polymerization heat treatments on the cytotoxicity of two denture base acrylic resins. MATERIALS AND METHODS: Nine disc-shaped specimens (10 x 1 mm) of each denture base resin (Lucitone 550 and QC 20) were prepared according to the manufacturers' recommendations and stored in distilled water at 37ºC for 48 h. The specimens were assigned to 3 groups: 1) post-polymerization in a microwave oven for 3 min at 500 W; 2) post-polymerization in water-bath at 55º C for 60 min; and 3) without post-polymerization. For preparation of eluates, 3 discs were placed into a sterile glass vial with 9 mL of Eagle's medium and incubated at 37ºC for 24 h. The cytotoxic effect of the eluates was evaluated by ³H-thymidine incorporation. RESULTS: The results showed that the components leached from the resins were cytotoxic to L929 cells, except for the specimens heat treated in water bath (pINTRODUÇÃO: A maioria das resinas acrílicas utilizadas para confecção de bases de próteses é composta pelo polimetacilato de metila. Muitos autores têm discutido o processo de polimerização dessas resinas em relação à conversão do monômero em polímero devido a sua importância na melhora da biocompatibilidade e das propriedades físicas. Para assegurar a utilização desses materiais, testes preliminares de citotoxicidade in vitro têm sido desenvolvidos para avaliação da biocompatibilidade. Um dos ensaios biológicos sugeridos para a análise da citotoxicidade é o teste de incorporação de ³H-timidina, o qual mede o número de células por meio da síntese de DNA. OBJETIVO: O objetivo do presente estudo foi avaliar, por meio do teste de incorporação de ³H-timidina, a citotoxicidade de duas resinas acrílicas para base de próteses submetidas aos tratamentos em microondas e em banho de água após a polimerização. MATERIAL E MÉTODO: Nove corpos-de-prova em forma de discos (10 x 1 mm) foram confeccionados com as resinas acrílicas Lucitone 550 e QC 20 de acordo com as instruções dos fabricantes, e foram armazenados em água destilada a 37ºC por 48 h. Os corpos-de-prova foram divididos em três grupos: 1) tratamento em forno de microondas por 3 min a 500 W; 2) tratamento em banho de água a 55ºC por 60 min; e 3) sem tratamento térmico. Extratos foram preparados pela colocação de 3 discos em tubos de ensaio estéreis com 9 mL de meio de cultura Eagle e incubação a 37ºC por 24 h. O efeito citotóxico dos extratos foi avaliado utilizando o teste de incorporação de ³H-timidina. RESULTADOS: Os resultados indicaram que os componentes liberados pelas resinas foram citotóxicos para as células L929 exceto para as amostras tratadas em banho de água (

Microbiological control of dental prostheses with photodynamic therapy

As próteses dentarias fixas ou removíveis podem ser utilizadas para readaptação estética e funcional de pacientes que apresentam dentes e tecidos contíguos ausentes. Uma prótese removível, ainda que adequadamente planejada e confeccionada, pode ocasionar alterações na microbiota bucal do paciente que a utiliza, resultando na colonização das superfícies protéticas por microrganismos patogênicos. Quando aderidos aos materiais que compõem as próteses, esses microrganismos podem ocasionar enfermidades locais, como a candidíase bucal, bem como infeções sistémicas nos pacientes com algum comprometimento sistémico. Além disso, existe a possibilidade da ocorr6ncia de contaminação cruzada entre profissionais odontológicos que manipulam as próteses durante o atendimento clinico ou ajustes no laboratório de prótese dentaria. Alguns métodos de desinfeção têm sido sugeridos como forma de prevenir a contaminação cruzada e tratar as infecções relacionadas a utilização de próteses removíveis. No entanto, os problemas associados a utilização de soluções químicas e o desenvolvimento de resistência microbiana as drogas antimicrobianas têm impulsionado a investigação de novos métodos de inativação microbiana e desinfecção de próteses. Diversos estudos desenvolvidos até o presente momento demonstram o potencial da terapia fotodinâmica (TFD) para inativação microbiológica, inclusive de espécies que constituem a microbiota bucal e podem ser encontradas colonizando próteses dentarias. Este artigo e uma revisão da literatura acerca da TFD para inativação microbiana e sua aplicação para controle microbiano em próteses dentarias

Comparison of denture microwave disinfection and conventional antifungal therapy in the treatment of denture stomatitis: a randomized clinical study

Objective. the aim of this study was to compare the effectiveness of denture microwave disinfection and antifungal therapy on treatment of denture stomatitis.Study Design. Sixty denture wearers with denture stomatitis (3 groups; n = 20 each), were treated with nystatin or denture microwave disinfection (1 or 3 times/wk) for 14 days. Mycologic samples from palates and dentures were quantified and identified with the use of Chromagar, and clinical photographs of palates were taken. Microbiologic and clinical data were analyzed with the use of a series of statistical tests (alpha = .05).Results. Both treatments similarly reduced clinical signs of denture stomatitis and growth on palates and dentures at days 14 and 30 (P > .05). At sequential appointments, the predominant species (P < .01) isolated was C. albicans (range 98%-53%), followed by C. glabrata (range 22%-12%) and C. tropicalis (range 25%-7%).Conclusions. Microwave disinfection, at once per week for 2 treatments, was as effective as topical antifungal therapy for treating denture stomatitis. (Oral Surg Oral Med Oral Pathol Oral Radiol 2012;114:469-479)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CESMAC Univ Ctr, Sch Dent, Maceio, BrazilUniv Estadual Ponta Grossa, Dept Dent, Ponta Grossa, BrazilUniversidade Federal de São Paulo, Div Infect Dis, São Paulo, BrazilUNESP Univ Estadual Paulista, Araraquara Dent Sch, Araraquara, BrazilUniversidade Federal de São Paulo, Div Infect Dis, São Paulo, BrazilFAPESP: 2005/03211-6FAPESP: 2005/04695-7Web of Scienc

Efeito do tratamento térmico em microondas e do tempo de armazenamento em água sobre a citotoxicidade de resinas acrílicas para base e reembasamento de próteses

A proposta do presente estudo foi avaliar, por meio do teste quantitativo de incorporação de 3H-timidina, o efeito do tratamento térmico em microondas sobre a citotoxicidade de três resinas termopolimerizáveis indicadas para confecção de bases de próteses, em função do tempo de armazenamento em água, e de três resinas autopolimerizáveis indicadas para reembasamento. A hipótese de que o tratamento térmico em microondas poderia diminuir a citotoxicidade de resinas acrílicas foi avaliada. Os materiais testados foram Lucitone 550 (a mufla foi imersa em água à temperatura de 730C permanecendo por 90 minutos, em seguida, à temperatura foi elevada para 1000C e a mufla mantida por mais 30 minutos), QC 20 (a mufla foi imersa em água em ebulição, o aquecimento foi mantido e a mufla permaneceu no recipiente por um período de 20 minutos contados a partir do momento em que a água atingiu novamente à temperatura de ebulição e Acron MC (a mufla foi levada ao forno de microondas durante 3 minutos à potência de 500 W) e os reembasadores Tokuyama Rebase II, Kooliner e New Truliner. Foram confeccionados, em condições assépticas, corpos-de-prova de cada resina em forma de discos medindo 10 mm de diâmetro e 1 mm de espessura. As amostras das resinas termopolimerizáveis foram armazenadas em água destilada por 0, 24 ou 48 horas a 37ºC. Para avaliar o efeito do tratamento térmico em microondas, os corpos-de-prova de todas as resinas foram divididos em dois grupos: 1) sem tratamento térmico e 2) com tratamento térmico em microondas, com as amostras imersas em água, irradiadas durante 3 minutos à 500 W. Os extratos das resinas foram preparados colocando-se três corpos-de-prova de cada grupo experimental, após terem recebido o tratamento térmico, em tubos de ensaio com 9 ml de meio de cultura Eagle e incubados a 37ºC por 24 horas. Um tubo de ensaio, contendo apenas 9 ml de meio...The aim of the current study was to evaluate the effect of microwave post-polymerization heat-treatments and water storage time on the cytotoxicity of denture base and reline acrylic resins. The hypothesis that post-polymerization treatment could decrease the cytotoxicity of acrylic base resins was tested in this study. The materials tested were Lucitone 550 (water-bath at a temperature of 73ºC for 90 minutes, followed by 30 minutes of heating at 100ºC), QC 20 (boil water, insert flask, return to boil, boil for 20 minutes) and Acron MC (microwave-polymerized, irradiated for 3 minutes at 500 W) and the hard chair-side reline resin Tokuyama Rebase II, Kooliner and New Truliner. Sample disks of the denture base resins were fabricated under aseptic conditions in mold 10 mm in diameter by 1 mm thick. The samples of the denture base acrylic resins were stored in distilled water for 0, 24 and 48 hours at 37ºC. To assess the biologic effect of the heat-treatment on the denture resins, samples fabricated were further divided into two groups: 1) samples without heat-treatment; and 2) sample were treated in microwave, immersed in water, irradiated for 3 minutes at 500 W. Eluates of the materials were prepared by placing three disks into a sterile glass vial with 9 ml of Eagle's medium supplemented with antibiotics and fetal bovine serum. These were incubated for 24 hours at 37ºC. Medium without disks was also incubated and diluted as above to serve as the control. L929 mouse fibroblasts (1 x 104 cell/ml) were cultivated in Eagle's medium supplemented with antibiotics and fetal bovine serum in 96 well culture plates and incubated for 24 hours at 37ºC in an air atmosphere containing 5% CO2. After 24 hours of incubation, the culture medium was replaced by 50 ml of eluate and 50 ml of fresh medium were added to each well of the 96-well culture plate and incubated for more... (Complete abstract, click electronic address below)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Gel against denture stomatitis: clinical report

The objective of this study is to report the clinical use of 2% Uncaria tomentosa gel against denture stomatitis (DS) as an alternative treatment. The patient was a 65-year-old, denture-wearing woman. At the clinical examination, her palate showed hyperplasic and erythematous mucosa indicating DS type II. DS is a chronic oral disease that affects denture wearers. It occurs as an inflammatory reaction in denture-wearing patients under maxillary prostheses. Candida albicans has been reported as the principal etiological agent. An alternative treatment, the topical application of a gel of 2% U. tomentosa three times a day for 1 week was given to the patient. After 1 week of this treatment, she had significantly reduced signs of the disease. Despite the existence of a great number of antifungal agents, treatment failure is observed frequently. Phytotherapy is becoming more popular worldwide. Currently, the most promising medicinal Amazonian herb is U. tomentosa (Willd.) DC., known as Cat's Claw. Studies of the chemical and pharmacological properties of this medicinal plant have allowed researchers to develop indications for its use. This report demonstrates the effectiveness of U. tomentosa against DS

Failures in the rehabilitation treatment with removable partial dentures

Background. Despite being functional and having aesthetic benefits, the acceptance of patients regarding the use of removable partial dentures (RPDs) has been low. In part, this is due to the deleterious effects that causes discomfort to the patient. Success depends not only on the care expended by the patient, including daily care and oral hygiene, but also on common goals set by their professional and clinical staff, aiming beyond aesthetics, to incorporate issues of functionality and the well-being of patients. Methods and results. For rehabilitation treatment with RPDs to reach the desired level of success without damaging the support structure, all the steps (diagnose, cavity preparation, adaptation of the metal structures, functional of distal extension and posterior follow-up) in the rehabilitative treatment should be carefully developed. A literature review was carried out, searching through MEDLINE (PubMed) articles published between 1965 and December 2012 including clinical trials and reviews about the use of RPDs. Conclusions. This study describes factors that lead to failures and complications in oral rehabilitation through the use of RPDs and suggests possible solutions

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

Cytotoxicity of denture base acrylic resins: A literature review

Acrylic resins are widely used in the fabrication of denture bases and have been shown to be cytotoxic as a result of substances that leach from the resin. The primary eluate is residual monomer. Numerous reports suggest that residual monomer may be responsible for mucosal irritation and sensitization of tissues. This information is important, not only to assess the biologic effects of such materials, but also to enable a comparison among the different polymerization methods, thus assisting the clinician in selecting a material with minimal cytotoxicity. This article reviews the literature published from 1973 to 2000, selected by use of a Medline search, associated with cytotoxic effects usually ascribed to acrylic denture base materials

Propiedades de materiales resilientes para rebase de prótesis

La presente revisión de literatura tiene por objetivo mostrar las principales características, ventajas y limitaciones de los rebases blandos con el fin de acercar su utilización al clínico general. Los materiales resilientes para rebase de prótesis han sido desenvueltos para minimizar las posibles molestias causadas por las bases de las prótesis en la mucosa. Estos materiales forman un grupo de materiales elásticos que llenan total o parcialmente la base de la prótesis,con la finalidad de disminuir el impacto de la fuerza masticatoria sobre la mucosa de revestimiento, pudiendo ser utilizados como material temporal o de un carácter más permanente. Los rebases blandos además de clasificarse según el tiempo de uso como provisionales (corta duración) o permanentes (larga duración), estos pueden ser divididos según la base del material: acrílico o silicona. Dentro de las indicaciones se encuentran la estabilización de prótesis despuésde cirugías, el condicionamiento de tejidos fibromucosos, el rebase de prótesis provisionales durante el periodo de óseo integración de implantes o como medio retentivo para sobredentaduras implanto-soportadas, además pueden ser utilizados como material para impresiones funcionales. A pesar de que los materiales resilientes para rebase de prótesis poseen algunas desventajas, estos pueden ser usados para el rebase de prótesis removible parcial o total con unbuen desempeño clínico, al indicarlas correctamente y por un tiempo determinado