Surface morphology and in vitro leachability of soft liners modified by the incorporation of antifungals for denture stomatitis treatment

Objective: To evaluate the surface morphology and in vitro leachability of temporary soft linings modified by the incorporation of antifungals in minimum inhibitory concentrations (MIC) for Candida albicans biofilm. Methodology: Specimens of soft lining materials Softone and Trusoft were made without (control) or with the addition of nystatin (Ny), miconazole (Mc), ketoconazole (Ke), chlorhexidine diacetate (Chx), or itraconazole (It) at their MIC for C. albicans biofilm. The surface analyses were performed using Confocal laser scanning microscopy after 24 h, 7 days, or 14 days of immersion in distilled water at 37ºC. In vitro leachability of Chx or Ny from the modified materials was also measured using Ultraviolet visible spectroscopy for up to 14 days of immersion in distilled water at 37ºC. Data (μg/mL) were submitted to ANOVA 1-factor/Bonferroni (α=0.05). Results: Softone had a more irregular surface than Trusoft. Morphological changes were noted in both materials with increasing immersion time, particularly, in those containing drugs. Groups containing Chx and It presented extremely porous and irregular surfaces. Both materials had biexponential release kinetics. Softone leached a higher concentration of the antifungals than Trusoft (p=0.004), and chlorhexidine was released at a higher concentration than nystatin (p<0.001). Conclusions: The surface of the soft lining materials changed more significantly with the addition of Chx or It. Softone released a higher concentration of drugs than Trusoft did, guiding the future treatment of denture stomatitis

Porosity, water sorption and solubility of denture base acrylic resins polymerized conventionally or in microwave

The proper selection of polymerization cycle is important to prevent overheating of the monomer that could cause degradation, porosity and, consequently, deleterious effects on the denture base properties. Objective: This study evaluated the porosity, water sorption and solubility of acrylic resins (Vipi Cril-VC and Vipi Wave-VW) after conventional or microwave polymerization cycles. Material and Methods: Specimens (n = 10) were made and cured: 1-WB = 65°C during 90 min + boiling during 90 min (VC cycle - control group); 2-M25 = 10 min at 270 W + 5 min at 0 W + 10 min at 360 W (VW cycle); 3-M3 = 3 min at 550 W; and 4-M5 = 5 min at 650 W. Afterward, they were polished and dried in a dessicator until a constant mass was reached. Specimens were then immersed in distilled water at 37°C and weighed regularly until a constant mass was achieved. For porosity, an additional weight was made with the specimen immediately immersed in distilled water. For water sorption and solubility, the specimens were dried again until equilibrium was reached. Data were submitted to 2 way-ANOVA and Tukey HSD (α=0.05). Results: Porosity mean values below 1.52% with no significant difference among groups for both materials were observed. Resins showed water sorption and solubility values without a significant difference. However, there was a significant difference among groups for these both properties (P<0.013). The highest sorption (2.43%) and solubility (0.13%) values were obtained for WB and M3, respectively. Conclusions: The conventional acrylic resin could be polymerized in a microwave since both the materials showed similar performance in the evaluated properties. Sho

INIBIÇÃO DA COLONIZAÇÃO DE STAPHYLOCOCCUS E CANDIDA APÓS A ADIÇÃO DE AGENTES ANTIMICROBIANOS EM CONDICIONADOR TECIDUAL

Esse estudo teve por objetivo avaliar a efetividade a longo prazo da incorporação de agentes antimicrobianos em um condicionador tecidual (Softone-Bosworth Co, IL, EUA) na inibição de colonização bacteriana (Staphylococcus aureus-Sa) e fúngica (Candida albicans-Ca). As doses dos agentes incorporados ao pó do material (6 g) foram: sem adição de droga-controle (G1); nistatina-500.000 U (G2) e 1.000.000 U (G3); miconazol-125 mg (G4) e 250 mg (G5); cetoconazol-100mg (G6) e 200mg (G7); diacetato de clorexidina a 5% (G8) e diacetato de clorexidina a 10% (G9). As amostras (n=144) (10 x 1 mm) foram colocadas em placas de ágar Mannitol Salt para Sa e de ágar Sabourand para Ca previamente semeadas, as quais foram incubadas a 37ºC por 14 dias para a mensuração diária dos halos de inibição. Os dados foram submetidos à ANOVA e teste de Tukey (α=0,05). Para Ca, as maiores médias de halos de inibição foram obtidas para G7 (22,2 mm) e G6 (20,2 mm) e as menores para G2 (12,2 mm) (P<0,05). Houve inibição fúngica por 14 dias nos grupos G4, G5, G6 e G7 (13,8-20,6; 15,8-22,8; 16,4-23 e 19,2-25,4 mm, respectivamente). G3 (10,4-17 mm) apresentou inibição de Ca por 13 dias; G9 (10,8-17,2 mm) e G2 (10,4-16 mm) por 12 dias e G8 (11-16,8 mm) por 11 dias. Para Sa, as maiores médias de halos de inibição foram obtidas para G8 (19,2 mm) e G9 (13,6 mm) e as menores para G2 (10,2 mm) (P<0,05). No G8, houve inibição de Sa por 14 dias (1,8-9,0 mm) e no G9 por 12 dias (10,8-17,2 mm). O Sa foi inibido por 2 dias nos grupos G3, G4, G5, G6 e G7 (12,2-13,8; 12-13,8; 12,6-13,6; 12,8-13,6; 13,6-14,2 mm, respectivamente) e por 1 dia no G2 (12,6 mm). Não houve inibição de Ca e Sa no G1. Quando incorporados ao condicionador tecidual, a clorexidina e o cetoconazol foram, a longo prazo, os agentes antimicrobianos mais efetivos na inibição de Sa e Ca, respectivamente

Porosity of temporary denture soft liners containing antifungal agents

Incorporation of antifungals in temporary denture soft liners has been recommended for denture stomatitis treatment; however, it may affect their properties. Objective: To evaluate the porosity of a tissue conditioner (Softone) and a temporary resilient liner (Trusoft) modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm. Material and Methods: The porosity was measured by water absorption, based on exclusion of the plasticizer effect. Initially, it was determined by sorption isotherms that the adequate storage solution for specimens (65×10×3.3 mm) of both materials was 50% anhydrous calcium chloride (S50). Then, the porosity factor (PF) was calculated for the study groups (n=10) formed by specimens without (control) or with drug incorporation at MICs (nystatin: Ny-0.032 g, chlorhexidine diacetate: Chx-0.064 g, or ketoconazole: Ke-0.128 g each per gram of soft liner powder) after storage in distilled water or S50 for 24 h, seven and 14 d. Data were statistically analyzed by 4-way repeated measures ANOVA and Tukey's test (α=.05). Results: Ke resulted in no significant changes in PF for both liners in water over 14 days (p>;0.05). Compared with the controls, Softone and Trusoft PFs were increased at 14-day water immersion only after addition of Ny and Chx, and Chx, respectively (p;0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared with distilled water (

EFEITO DA ADIÇÃO DE AGENTES ANTIMICROBIANO/ANTIFÚNGICO SOBRE DUREZA E RUGOSIDADE SUPERFICIAL DE CONDICIONADOR TECIDUAL

O objetivo desse estudo foi determinar o efeito da incorporação de antifúngicos (nistatina- N, miconazol- M ou cetoconazol- K) ou de agente antimicrobiano (diacetato de clorexidina-C) sobre propriedades físicas de um condicionador de tecido (Softone-S). Foi avaliado o padrão de incorporação destas drogas no material S por MEV/EDS. Os grupos avaliados foram: G1 = controle (sem adição de droga); G2 = N-500.000 U; G3 = N-1.000.000 U; G4 = M-125 mg; G5 = M-250 mg; G6 = K-100 mg; G7 = K-200 mg; G8 = C-5% e G9 = C-10% em relação à quantidade total (6 g) de S. As quantidades das drogas (em pó) foram misturadas ao pó de S, sendo o líquido de S posteriormente adicionado à mistura. Amostras (n = 5) foram plastificadas à temperatura ambiente por 10 min. As leituras de dureza (Shore A) e rugosidade (Ra) foram realizadas após imersão das amostras em água destilada a 37°C por 24 h, 7 e 14 dias. Os resultados foram analisados pela análise de variância (2-ANOVA)/ Tukey (α = 0,05). Após todos os períodos avaliados (24 h, 7 e 14 dias), a dureza dos grupos experimentais foi superior (P 0,05) à do G1 (5,83 µm). Após 14 dias, a rugosidade do G5, G8 e G9 foi superior (P < 0,05) (7,93; 9,63 e 10,29 µm, respectivamente) à do G1 (6,92 µm). O material modificado demonstrou morfologia favorável, por meio de MEV/EDS, para liberação intra-bucal das drogas avaliadas. Foram observadas alterações nas propriedades físicas do material modificado, entretantodeve-se avaliar se são clinicamente significantes

A novel acrylic resin palatal device contaminated with Candida albicans biofilm for denture stomatitis induction in Wistar rats

Denture stomatitis is the most frequent oral lesion in removable prosthesis wearers, with high recurrence rates and a complex treatment.&nbsp;Objective:&nbsp;This study describes a protocol to obtain and to contaminate a palatal device with Candida albicans biofilm that could be used for an animal model of denture stomatitis.&nbsp;Methodology: Acrylic resin devices (N=41) were obtained from impressions of the palates of Wistar rats with individual trays and polyether. The efficacy of microwave irradiation (MW), ultraviolet light (UV), or ultrasonic bath (US) was assessed by colony viability and spectrophotometric analyses (n=5) in order to select the most appropriate method for sterilizing the devices. Then, different devices (n=5) were contaminated with C. albicans and evaluated by CFU/mL determination, scanning electron microscopy, and laser confocal microscopy. Device stabilization was assessed with either autopolymerizing acrylic resins or a self-adhesive resin cement (n=2). The spectrophotometric data were analyzed by one-way ANOVA followed by the Tukey’s HSD post-hoc test (α=0.05).&nbsp;Results: MW was the only method capable of sterilizing the devices, and the contamination protocol developed a mature and viable C. albicans biofilm (~1.2 x 106 CFU/mL). The self-adhesive resin cement was the best stabilization material.&nbsp;Conclusions: This acrylic resin palatal device was designed to be similar to the clinical situation of contaminated prostheses, with easy manufacturing and handling, effective stabilization, and satisfactory contamination. Thus, the acrylic device can be a valuable tool in the development of denture stomatitis in rats

Efeito de diferentes tratamentos térmicos sobre o conteúdo de monômero residual de resinas acrílicas para reembasamento

O objetivo deste estudo foi estabelecer, inicialmente, um método analítico em CLAE, para comparar o conteúdo de monômero residual de uma resina autopolimerizável para reembasamento imediato (Duraliner II - D) e uma resina termopolimerizável utilizada na confecção de bases de próteses (Lucitone 550 - L). Além disso, foi avaliado o efeito de dois tratamentos térmicos sobre esse conteúdo. Os monômeros utilizados como padrões foram o MMA (resina L) e o BMA (resina D). As condições cromatográficas para a análise foram: coluna ODS (15,0 x 0,46 cm), com 5 mm de tamanho de partícular e 100 Å de tamanho de poro, fase móvel ACN : H2O (55%: 45%) + 0,01% TEA, fluxo 0,8 mL/min, l 230 nm, volume de injeção 100 mL. As resinas foram proporcionadas e polimerizadas de acordo com as instruções dos fabricantes. Os corpos-de-prova (n = 18) dos dois materiais foram divididos em 3 grupos, com 6 corpos-de-prova cada. O grupo I (GI) não foi submetido a nenhum tratamento (controle). Para o grupo II (GII), os corpos-de-prova foram irradiados com microondas, a 550 W por 3 min para o material L e a 650 W por 4 min para o material D. Para o grupo III (GIII), os corpos-de-prova dos materiais L e D foram submetidos ao tratamento térmico por imersão em água a 55oC por 60 min e 10 min, respectivamente. Cada corpo-de-prova foi, então, fragmentado e submetido ao procedimento de extração em MeOH por 2 horas. Os valores de conteúdo de monômero residual foram transformados em porcentagem e analisados pelo teste de Kruskall-Wallis, ao nível de confiança de 99%. Em todos os grupos avaliados, o material D apresentou valores médios de monômero residual (GI - 0,87%; GII - 0,71%; GIII - 0,52%) significativamente maiores (p<0,01) que o material L (GI - 0,09%; GII - 0,06%; GIII - 0,05%). De acordo com a metodologia utilizada neste estudo, foram obtidas as seguintes conclusões: 1) O método...The aim of this study was to firstly establish an analytical method, which was the most satisfactory with reference to optimization of chromatographic conditions for HPLC. The method was then used to compare the residual monomer content in one hard chair-side reline resin (Duraliner II - D) and one heat-polymerized denture base resin (Lucitone 550 - L). Also, it was investigated the effect of two after polymerization heat-treatments on this residual monomer content. The HPLC operating conditions established were column ODS (15.0 x 0.46 cm), with 5 mm particles, mobile phase - 55% ACN : 45% deionized distilled water, flow injection rate - 0.8 mL/min., wave length detection - UV 230 nm, amount of sample solution injection 100 mL. Calibration curves were produced using standard solutions containing known amounts of each monomer evaluated (MMA - L; BMA - D) in mobile phase. The materials (D and L) were mixed and polymerized according to the manufacturer's instructions. Specimens (n = 18) of both materials were then divided into three groups, of six specimens each. Group I specimens were left untreated (GI - control). Specimens of group II (GII) were given heat treatment by microwave irradiation with 550 W for 3 min for material L and 650 W for 4 min for material D. For group III (GIII), L and D specimens were submitted to a heat-treatment by immersion in water at 55oC for 60 min and 10 min, respectively. Each specimen were cut into small pieces and subjected to an extraction procedure in methanol for 2 hours. The residual monomer content was then expressed as a percentage of residual monomer in the specimen. The percentage residual monomer data were analyzed by non-parametric Kruskall-Wallis test, at 99% level of confidence. In all groups evaluated, material D showed significantly higher (p<0.01) residual monomer mean values (GI - 0.87%; GII - 0.71%; ...(Complete abstract, click electronic access below)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