Nonmetal clasp dentures: What is the evidence about their use?

The aim was to discuss the indications, contraindications, advantages, and disadvantages of Nonmetal clasp dentures (NMCDs), as well as the most relevant properties of its constituent materials. A search was conducted using the keywords: "nonmetal clasp dentures," "thermoplastic resin," "flexible resin removable partial denture," "polyamide," and "nylon" in databases PubMed/Medline, Lilacs, SciELO, and textbooks between 1955 and 2020. Theses and texts without reliable sources of publication were excluded. Once the analysis instruments were determined, the data were analyzed and discussed. NMCDs present high flexibility, easy adaptation to the abutments, color compatibility and biocompatibility with the oral mucosa, and absence of visible metal clasps. However, they need laboratory relining, grinding, and polishing, do not have criteria for its planning, become rougher and stained over time, and are able to traumatize supporting tissues. The association with metal components seems to be an alternative to increase the success of NMCDs by combining esthetics and biomechanical principles of conventional removable partial dentures. The lack of long-term clinical studies makes the professionals to rely solely on previous experiences or on the manufacturers' recommendations. It suggested that NMCDs must be indicated with caution when not used temporarily.

In vivo biocompatibility of an interim denture resilient liner containing antifungal drugs.

STATEMENT OF PROBLEM: Antifungal agents incorporated into interim denture resilient liners have been suggested as an adjunct treatment for denture stomatitis (DS). However, before applying this protocol to humans, biocompatibility analysis of such drugs in animal models is required. PURPOSE: The purpose of this animal study was to evaluate the in vivo biocompatibility of an interim resilient liner modified with minimum inhibitory concentrations (MICs) of antifungal drugs for Candida albicans biofilm. MATERIAL AND METHODS: Sixty Wistar rats were divided into 6 groups (n=5): PC=positive control/no protocol; IOD (intraoral device)=rats using an acrylic resin palatal device (PD); Tru=rats using a PD relined with Trusoft; and Ny (nystatin), Chx (chlorhexidine diacetate), and Ke (ketoconazole) groups=rats using a PD relined with Trusoft + drug MICs. The rats were sacrificed at 7 or 14 days of trial. Histopathological qualitative analysis was performed by comparing photomicrographs of histological sections of the intermolar region. Morphological changes in the epithelium and keratin were quantitatively analyzed by computerized planimetry, and data were analyzed by using 2-way ANOVA and the Tukey HSD test (α=.05). RESULTS: Quantitative analysis showed that only PD containing Ke significantly decreased the thickness and area of the keratin compared with the other groups (P<.001), which showed no differences between each other (P>.05). These results agreed with those of qualitative analysis. CONCLUSIONS: Incorporation of MICs of Ny and Chx in Trusoft did not induce histopathological changes in the rat palatal mucosa, suggesting the in vivo biocompatibility of this DS treatment.

Effect of Incorporation of Antifungal Agents on the Ultimate Tensile Strength of Temporary Soft Denture Liners.

PURPOSE: To investigate the ultimate tensile strength of temporary soft denture liners modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm (SC5314) determined in previous microbiological research. MATERIALS AND METHODS: Dumbbell-shaped specimens (n = 7) with a central cross-sectional area of 6 × 3 × 33 mm were produced by Softone and Trusoft, without (control) or with incorporation of drugs in powder form at MICs for C. albicans biofilm (per g of material powder): nystatin (0.032 g), chlorhexidine diacetate (0.064 g), ketoconazole (0.128 g), miconazole (0.256 g), and itraconazole (0.256 g). After plasticization, specimens were immersed in distilled water at 37°C for 24 hours, 7 or 14 days, and then tested in tension in a universal testing machine at 40 mm/min. Data of tensile strength (MPa) and elongation percentage (%) were submitted to 3-way ANOVA and Tukey's test (α = 0.05). RESULTS: At the end of 14 days, the tensile strength for both materials was significantly lower in the groups modified by miconazole and itraconazole compared to the other groups (p < 0.0001), which showed no significant difference between them (p > 0.05). After 7 and 14 days in water, miconazole and itraconazole added into both materials resulted in significantly lower elongation percentages compared to the other antifungal agents and control (p < 0.0001), which were similar to each other (p > 0.05). CONCLUSIONS: The addition of the nystatin, chlorhexidine, and ketoconazole at MICs for C. albicans biofilm resulted in no harmful effects on the tensile strength and elongation percentage of the temporary soft denture liner materials up to 14 days.

Sucesso de enxertos ósseos complementares em fissuras labiopalatinas e sobrevivência de implantes dentários / Success of compementary bone grafts in patients with cleft lip and palate and survival of dental implants

Este estudo teve por objetivo monitorar a eficácia de implantes dentais inseridos em áreas receptoras de re-enxerto autógeno (enxerto em bloco intraoral) e identificar os fatores de risco relevantes para o prognóstico em pacientes com fissuras labiopalatinas. Foi realizado um levantamento retrospectivo das informações clínicas registradas nos prontuários dos pacientes do Hospital de Reabilitação de Anomalias Craniofaciais (USP), de 1999 até os casos finalizados em abril de 2009. Foram avaliados os prontuários de 161 pacientes, de ambos os sexos, submetidos à cirurgia de enxerto ósseo em bloco para complementação óssea em volume e/ou altura para posterior instalação de implante, na região da fissura ou fora dela. Os enxertos foram obtidos de ramo mandibular ou mento. Em 161 pacientes foram realizados 211 enxertos ósseos intraorais autógenos, sendo 2% destes realizados com finalidade de auxiliar a movimentação ortodôntica. Foram instalados 160 implantes nessas áreas, em 76% dos blocos, visto que 22% dos enxertos ósseos autógenos falharam antes mesmo da instalação de implantes. Considerando a sobrevivência dos implantes instalados nas áreas enxertadas, 15% dos implantes foram removidos por falta de osteointegração, resultando em uma taxa de sobrevivência equivalente a 85% nos blocos bem-sucedidos. Embora a sobrevivência dos implantes em áreas de re-enxerto seja compatível com outros relatos na literatura, tais implantes apresentaram maiores falhas do que implantes instalados em áreas de fissura que receberam apenas enxerto ósseo alveolar secundário (AU).

This study aimed to monitor dental implants efficacy inserted in regrafted areas with autogenous bone (intra-oral block grafts) and to identify relevant risk factors for cleft lip and palate patients prognosis. A retrospective research collected clinical information registered in the medical records of Craniofacial Anomalies Rehabilitation Hospital - São Paulo University (HRAC-USP) from 1999 up to the April 2009. A hundred and sixty-one patient's records were evaluated, of both sexes, submitted to block bone graft surgery for bone complementation in volume and/or height for further implant installation, in the cleft region or out of it. Grafts were taken either from mandibular branch or chin. Two hundred and eleven intraoral autogenous block bone grafts were done in a hundred and sixty-one patients, 2% of these with the aim of orthodontic movement support. A hundred and sixty implants were installed in these areas, in 76% of the blocks as 22% of the autogenous bone grafts failed before implant installation. Considering implant survival rates in grafted areas, 15% of the implants were removed due to lack of osseointegration, resulting in a successful survival rate of 85% for successful bone blocks. Although implant survival rates in regrafted areas are compatible with other literature records, these implants had greater failure rates if compared to those of cleft areas that received only secondary alveolar bone grafting (AU).

Taxa de sobrevivência de implantes instalados em área de levantamento de seio maxilar em pacientes com fissura labiopalatinas / Survival rate of implants installed at maxillary sinus lifting areas in cleft lip and palate patients

O objetivo deste estudo foi avaliar a taxa de sobrevivência de implantes instalados em áreas previamente submetidas à cirurgia de levantamento de seio maxilar (LSM) em pacientes com fissura labiopalatina do Hospital de Reabilitação de Anomalias Craniofaciais da Universidade de São Paulo (HRAC-USP). Uma busca eletrônica retrospectiva foi realizada em 60.000 prontuários de pacientes do HRAC de 1998 a 2007. Essa busca resultou em 58 pacientes (15 masculinos e 43 femininos, média de idade de 36 anos) que foram submetidos a procedimentos cirúrgicos de enxerto ósseo no seio maxilar e tiveram implantes osseointegráveis instalados nesta área, compreendendo 83 procedimentos de LSM e 161 implantes instalados (38 do sexo masculino e 123 do feminino). As informações clínicas destes pacientes foram registradas em prontuários com exames radiográficos. Foi tomada análise descritiva e as porcentagens de sobrevivência e falha foram obtidas. Visava-se reduzir as falhas nas reabilitações de pacientes edêntulos totais ou parciais e ganhar experiência nesta área. Como resultados, foi constatado que técnicas de implantes imediatos mostraram taxa de sobrevivência de 94,94%, enquanto a técnica cirúrgica de implantes em segunda instância apresentou taxa de sobrevivência de 93,9%. Baseados nos resultados obtidos e considerando os limites da metodologia deste estudo, concluiu-se que o LSM é uma opção de tratamento excelente, desde que sua indicação seja corretamente seguida (AU).

The aim of this study was to evaluate the survival rate of implants installed in areas where maxillary sinus lifting surgeries had been previously performed in clef lip and palate patients of Hospital for Rehabilitation of Craniofacial Anomalies - São Paulo University (HRAC-USP). A retrospective electronic search was performed in 60,000 files of HRCA patients from 1998 to 2007. This search resulted in 58 patients (15 male and 43 female, mean age of 36 years old) who had been submitted to maxillary sinus bone grafting procedures and had osseointegrated implants installed in those areas, comprising 83 maxillary sinus lifting (MSL) procedures and 161 implants installed (38 male and 123 female). The clinical information concerning those patients was registered in dental records with radiographic examinations. A descriptive analysis was performed and the percentage of survival and failure rates were obtained. The main objective was to reduce the rehabilitation failures of completely or partially edentulous patients and to gain experience in this field. As results immediate implants technique showed a survival rate of 94.94%, while second stage implants surgery technique presented a survival rate of 93.9%. Therefore, based on the results obtained and considering the study methodology limitations, it can be concluded that maxillary sinus lifting (MSL) procedure is an excellent treatment option, as long as its indications are correctly followed (AU).

Surface Properties of Temporary Soft Liners Modified by Minimum Inhibitory Concentrations of Antifungals.

Evaluating the addition of minimum inhibitory concentrations (MICs) of antifungals for Candida albicans biofilm on the hardness and roughness of temporary denture soft liners. Specimens (n=8; 36×7×6 mm) of tissue conditioner (Softone) and resilient liner (Trusoft) were produced either without (control) or with incorporation of drugs at MICs: nystatin (0.032 g/mL), chlorhexidine diacetate (0.064 g/mL), ketoconazole (0.128 g/mL), miconazole (0.256 g/mL) and itraconazole (0.256 g/mL). Specimens were stored in distilled water at 37 °C for 24 h, 7 days and 14 days prior to the hardness/roughness measurements. Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). The addition of the antifungals into both materials demonstrated no evident hardness change or decrease of this property compared with the control, except for miconazole in Softone, which increased the hardness after 14 days (p=0.003). The addition of nystatin into both materials, chlorhexidine in Trusoft and ketoconazole in Softone resulted in no significant changes of roughness compared with the control, after 7 days and 14 days (p>0.05). In these periods, itraconazole increased the roughness of both materials (p<0.001). The addition of all antifungals, except for the miconazole in Softone, resulted in no deleterious effects on the materials' hardness over the evaluation time. The MICs of nystatin in both temporary soft lining materials, ketoconazole in Softone and chlorhexidine in Trusoft resulted in no deleterious effects for roughness up to 14 days.

Surface Properties of Temporary Soft Liners Modified by Minimum Inhibitory Concentrations of Antifungals

Abstract Evaluating the addition of minimum inhibitory concentrations (MICs) of antifungals for Candida albicans biofilm on the hardness and roughness of temporary denture soft liners. Specimens (n=8; 36×7×6 mm) of tissue conditioner (Softone) and resilient liner (Trusoft) were produced either without (control) or with incorporation of drugs at MICs: nystatin (0.032 g/mL), chlorhexidine diacetate (0.064 g/mL), ketoconazole (0.128 g/mL), miconazole (0.256 g/mL) and itraconazole (0.256 g/mL). Specimens were stored in distilled water at 37 °C for 24 h, 7 days and 14 days prior to the hardness/roughness measurements. Data were analyzed by 3-way ANOVA and Tukey HSD test (α=0.05). The addition of the antifungals into both materials demonstrated no evident hardness change or decrease of this property compared with the control, except for miconazole in Softone, which increased the hardness after 14 days (p=0.003). The addition of nystatin into both materials, chlorhexidine in Trusoft and ketoconazole in Softone resulted in no significant changes of roughness compared with the control, after 7 days and 14 days (p>0.05). In these periods, itraconazole increased the roughness of both materials (p<0.001). The addition of all antifungals, except for the miconazole in Softone, resulted in no deleterious effects on the materials’ hardness over the evaluation time. The MICs of nystatin in both temporary soft lining materials, ketoconazole in Softone and chlorhexidine in Trusoft resulted in no deleterious effects for roughness up to 14 days.

Resumo Avaliar a adição de antifúngicos nas mínimas concentrações inibitórias (MCIs) para o biofilme de Candida albicans sobre a dureza e rugosidade da reembasadores resilientes temporários. Foram confeccionados corpos de prova (n=8; 36×7×6 mm) a partir de um condicionador de tecido (Softone) e um reembasador resiliente (Trusoft), sem (controle) ou com a incorporação de fármacos nas MCIs: nistatina (0,032 g/mL), diacetato de clorexidina (0,064 g/mL), cetoconazol (0,128 g/mL), miconazol (0,256 g/mL) e itraconazol (0,256 g/mL). Os corpos de prova foram armazenados em água destilada a 37 °C durante 24 h, 7 dias e 14 dias antes das mensurações de dureza e rugosidade. Os dados foram analisados por ANOVA 3-fatores e teste de Tukey HSD (α=0,05). A adição dos antifúngicos em ambos os materiais não demonstrou nenhuma alteração evidente na dureza ou diminuiu esta propriedade em comparação com o controle, exceto para o miconazol no Softone que aumentou a dureza após 14 dias (p=0,003). A adição de nistatina aos dois materiais, clorexidina no Trusoft e cetoconazol no Softone não resultou em alterações significativas de rugosidade em comparação com o controle após 7 e 14 dias (p>0,05). Nestes períodos, o itraconazol aumentou a rugosidade de ambos os materiais (p<0,001). A adição de todos os antifúngicos, exceto para o miconazol no Softone, não resultou em efeitos deletérios sobre a dureza dos materiais ao longo do tempo de avaliação. As MCIs de nistatina em ambos os materiais reembasadores resilientes temporários, cetoconazol no Softone e clorexidina no Trusoft não produziram efeitos deletérios para a rugosidade em até 14 dias.

Intraoral Device for Optimal Antifungal Delivery in a Rat Model.

BACKGROUND: Antifungal agents incorporated into temporary denture resilient liners as drug carriers and delivery have been suggested as an alternative treatment for denture stomatitis. However, to test the in vivo biocompatibility of this protocol, standardization of an intraoral device for optimal drug delivery is required. OBJECTIVE: Standardized criteria were produced to adjust an acrylic intraoral device (IOD) for rats feasible for denture stomatitis treatment by sustained drug-delivery based on minimal inhibitory drug concentrations (MICs) of antifungals for Candida albicans biofilm. METHOD: Adjustments methodological involved diet, impression technique, type of retention device to the palate and histopathological analysis. 115 Wistar rats were tested without IOD, with devices without relining or relined with temporary resilient material (Trusoft) modified or not by drugs at MICs (nystatin-0.032g/mL; chlorhexidine diacetate-0.064g/mL; ketoconazole-0.128g/mL). The animals were sacrificed after 7 or 14 days from the IOD installation. RESULTS: Paste diet enabled the best animal survival conditions. The IODs that most satisfactorily remained in position were those designed only to the posterior palatal mucosa and cement-retained in molars, being all obtained from impressions highly detained and individual. In both periods, Trusoft without/with drugs showed good performance. Only histological samples from hard/soft tissues were considered appropriate for region of interest-RI determination (n=12), which corresponded to the area restricted to the first molars between the palatal neurovascular bundles. Final samples of all groups allowed a standardized descriptive histopathological analysis in both periods. CONCLUSION: The methodological standardization of this rat model resulted in IODs for optimal antifungal delivery for denture stomatitis treatment.

Porosity of temporary denture soft liners containing antifungal agents.

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). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared with the controls (p>0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared with distilled water (p<0.05). CONCLUSIONS:: The addition of antifungals at MICs resulted in no harmful effects for the porosity of both temporary soft liners in different periods of water immersion, except for Chx and Ny in Softone and Chx in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion.

Porosity of temporary denture soft liners containing antifungal agents

ABSTRACT 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). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared with the controls (p>0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared with distilled water (p<0.05). Conclusions: The addition of antifungals at MICs resulted in no harmful effects for the porosity of both temporary soft liners in different periods of water immersion, except for Chx and Ny in Softone and Chx in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion.

Biocompatibilidade in vivo de material resiliente temporário para base de prótese modificado por antimicrobianos para tratamento da estomatite protética / Biocompatibility in vivo of temporary soft denture liner for denture base modified by antimicrobials agents for denture stomatitis treatment

Reembasadores resilientes temporários contendo fármacos antifúngicos foram sugeridos como um tratamento adjunto para estomatite protética. No entanto, antes de utilizar clinicamente estes reembasadores modificados em humanos, é importante avaliar a sua biocompatibilidade em modelos animais. Este estudo avaliou a biocompatibilidade in vivo de um reembasador resiliente temporário para base de prótese (Trusoft) modificado por agentes antimicrobianos em suas mínimas concentrações inibitórias (MCIs) para biofilme de Candida albicans. Dispositivos acrílicos intra-orais (DIOs) foram confeccionados individualmente para 60 ratos Wistar. Os ratos foram divididos em 6 grupos (n=5): 3 grupos controle (Negativo: sem DIO; Geral: DIO sem reembasamento; Positivo: DIO reembasado com Trusoft sem fármacos) e 3 grupos experimentais (DIOs reembasados com Trusoft modificados por fármacos em suas respectivas MCIs: 0,032 g de nistatina, 0,064 g de diacetato de clorexidina e 0,128 g de cetoconazol). Os ratos com ou sem os DIOs foram eutanasiados após 7 e 14 dias de avaliação. A análise histopatológica qualitativa foi realizada comparando-se fotomicrografias de secções histológicas, que foram obtidas utilizando um microscópio óptico que abrangeu transversalmente a região intermolares. As alterações morfológicas no epitélio e queratina foram analisadas quantitativamente através da realização de planimetria computadorizada. Os dados quantitativos foram analisados utilizando ANOVA 2-fatores e teste de Tukey (=0,05). A análise quantitativa mostrou que apenas o grupo com DIO contendo cetoconazol diminuiu significativamente a espessura e a área do estrato córneo em comparação com os outros grupos (p<0,05), que não apresentaram diferenças significativas entre si (p>0,05). Estes resultados estiveram de acordo com os obtidos para análise qualitativa. A incorporação de MCIs de nistatina e diacetato de clorexidina no Trusoft não induziram alterações histopatológicas na mucosa palatina de ratos, sugerindo a biocompatibilidade in vivo deste protocolo para o tratamento de estomatite protética.(AU)

Temporary resilient denture liners containing antifungal drugs have been suggested as an adjunct treatment for denture stomatitis. However, before clinically using these modified liners in humans, it is important to assess their biocompatibility in animal models. This study evaluated the in vivo biocompatibility of a temporary soft denture liner (Trusoft) modified by antimicrobial agents at their minimum inhibitory concentrations (MICs) for biofilm formation by Candida albicans. Methods: Acrylic intraoral devices (IODs) were individually made for 60 Wistar rats. The rats were divided into the following 6 groups (n=5): 3 control groups (Negative: without IOD; General: IOD without relining; Positive: IOD relined with Trusoft without drugs) and 3 experimental groups (IOD relined with Trusoft modified by drugs at MICs: 0.032 g for nystatin, 0.064 g for chlorhexidine diacetate, and 0.128 g for ketoconazole). The rats with or without the IODs were sacrificed after 7 or 14 days of evaluation. Histopathological qualitative analysis was performed by comparing photomicrographs of histological sections, which were obtained using an optical microscope that transversely covered the inter-molar region. Morphological changes in the epithelium and keratin were quantitatively analyzed by performing computerized planimetry. Quantitative data were analyzed using 2-way ANOVA and Tukey's test (=0.05). Quantitative analysis showed that only the group with IOD containing ketoconazole significantly decreased the thickness and area of the stratum corneum compared with the other groups (p<0.05), which showed no significant differences between each other (p>0.05). These results were in accordance with those obtained for qualitative analysis. Incorporation of MICs of nystatin and chlorhexidine diacetate in Trusoft did not induce histopathological changes in the palatal mucosa of rats, suggesting the in vivo biocompatibility of this protocol for treating denture stomatitis.(AU)

Surface properties of multilayered, acrylic resin artificial teeth after immersion in staining beverages.

OBJECTIVE: To evaluate the effect of staining beverages (coffee, orange juice, and red wine) on the Vickers hardness and surface roughness of the base (BL) and enamel (EL) layers of improved artificial teeth (Vivodent and Trilux). MATERIAL AND METHODS: Specimens (n=8) were stored in distilled water at 37°C for 24 h and then submitted to the tests. Afterwards, specimens were immersed in one of the staining solutions or distilled water (control) at 37°C, and the tests were also performed after 15 and 30 days of immersion. Data were analyzed using 3-way ANOVA and Tukey's test (α=0.05). RESULTS: Vivodent teeth exhibited a continuous decrease (p<0.0005) in hardness of both layers for up to 30 days of immersion in all solutions. For Trilux teeth, similar results were found for the EL (p<0.004), and the BL showed a decrease in hardness after 15 days of immersion (p<0.01). At the end of 30 days, this reduction was not observed for coffee and water (p>0.15), but red wine and orange juice continuously reduced hardness values (p<0.0004). Red wine caused the most significant hardness changes, followed by orange juice, coffee, and water (p<0.006). No significant differences in roughness were observed for both layers of the teeth during the immersion period, despite the beverage (p>0.06). CONCLUSIONS: Hardness of the two brands of acrylic teeth was reduced by all staining beverages, mainly for red wine. Roughness of both layers of the teeth was not affected by long-term immersion in the beverages.

Surface properties of multilayered, acrylic resin artificial teeth after immersion in staining beverages

AbstractObjective To evaluate the effect of staining beverages (coffee, orange juice, and red wine) on the Vickers hardness and surface roughness of the base (BL) and enamel (EL) layers of improved artificial teeth (Vivodent and Trilux).Material and Methods Specimens (n=8) were stored in distilled water at 37°C for 24 h and then submitted to the tests. Afterwards, specimens were immersed in one of the staining solutions or distilled water (control) at 37°C, and the tests were also performed after 15 and 30 days of immersion. Data were analyzed using 3-way ANOVA and Tukey’s test (α=0.05).Results Vivodent teeth exhibited a continuous decrease (p<0.0005) in hardness of both layers for up to 30 days of immersion in all solutions. For Trilux teeth, similar results were found for the EL (p<0.004), and the BL showed a decrease in hardness after 15 days of immersion (p<0.01). At the end of 30 days, this reduction was not observed for coffee and water (p>0.15), but red wine and orange juice continuously reduced hardness values (p<0.0004). Red wine caused the most significant hardness changes, followed by orange juice, coffee, and water (p<0.006). No significant differences in roughness were observed for both layers of the teeth during the immersion period, despite the beverage (p>0.06).Conclusions Hardness of the two brands of acrylic teeth was reduced by all staining beverages, mainly for red wine. Roughness of both layers of the teeth was not affected by long-term immersion in the beverages.

Hardness and surface roughness of enamel and base layers of resin denture teeth after long-term repeated chemical disinfection.

AIM: To evaluate the effect of successive cycles of disinfection in different denture cleansers on the surface roughness and the Vickers hardness of two layers of acrylic resin (base-BL and enamel-EL) of two commercial cross-linked artificial teeth. MATERIALS AND METHODS: The occlusal surfaces of 60 acrylic resin denture posterior teeth (Trilux-TLX and SR Orthosit PE-SRO) embedded in autopolymerizing acrylic resin were ground fat with 1200-grit silicon carbide paper. Specimens were stored in distilled water at 37°C and then submitted to the microhardness (VHN) and roughness (µm) tests. Specimens were stored in distilled water at 37°C for 90 days and submitted to 720 disinfection cycles in sodium hypochlorite at 0.5%, 30% vinegar solution or distilled water (control). Afterward, micro-hardness and roughness tests were again performed. Data were analyzed using two-way ANOVA and Tukey's test (α=0.05). RESULTS: Hypochlorite immersion decreased the hardness of BL and EL of SRO teeth, with an average reduction of 10.11% (p<0.008). TLX teeth demonstrated a hardness reduction of 28.96% of both layers for all solutions including water (p<0.0000). The roughness of both teeth was not affected by denture cleansers (p>0.37). CONCLUSION: Hypochlorite promoted deleterious effects on the hardness of both layers of the artificial teeth tested. Immersion in vinegar and water also resulted in reduction of hardness of TLX teeth. CLINICAL SIGNIFICANCE: The surface hardness of the different layers of cross-linked artificial teeth can be altered by daily disinfection in denture cleansers commonly indicated for removable dentures.

Viabilidade do uso de dispositivo acrílico intra-oral reembasado por material resiliente temporário modificado por antimicrobianos: estudo preliminar em ratos / Viability of using an intraoral acrylic device relined by resilient material temporarily modified with antimicrobial agents: a preliminary study in rats

O objetivo deste estudo preliminar foi obter padrões metodológicos para viabilizar a utilização de um dispositivo acrílico intra-oral adaptável à mucosa palatina de ratos e passível de reembasamento com material resiliente temporário (Trusoft) modificado com antimicrobianos em suas mínimas concentrações inibitórias (MCIs) para biofilme de Candida albicans. Para delinear essa adequação, foram determinados parâmetros em relação à dieta e alojamento dos animais enquanto usuários desses dispositivos. A amostra total dos ratos (n=115) foi dividida em seis grupos: Controle Negativo (CN): sem dispositivo acrílico intra-oral; Controle Geral (CG): dispositivo acrílico sem reembasamento; Controle Positivo (CP): dispositivo reembasado com Trusoft sem fármaco; Diacetato de Clorexidina (CLO): dispositivo reembasado com Trusoft contendo clorexidina (0,064 g/mL); Cetoconazol (CET): dispositivo reembasado com Trusoft contendo cetoconazol (0,128 g/mL) e Nistatina (NIS): dispositivo reembasado com Trusoft contendo nistatina (0,032 g/mL). Os animais foram eutanasiados após 7 ou 14 dias da instalação dos dispositivos intraorais. As adaptações para a obtenção dos dispositivos incluíram a técnica de moldagem, método de reembasamento e formas de retenção à mucosa palatina dos animais. Para proporcionar a análise histopatológica descritiva padronizada, foram estabelecidos critérios em relação à obtenção das amostras histológicas, à seleção da região de interesse (RI) da análise e aos determinantes utilizados na descrição. Foi observado que a dieta pastosa e o alojamento em gaiolas com piso aramado sobre base de maravalha e papel craft possibilitaram melhores condições de sobrevivência aos animais. Os dispositivos intra-orais confeccionados individualmente e retidos via amarrilhos com fios ortodônticos nos incisivos e molares se mantiveram satisfatoriamente em posição durante todo o experimento para a maioria dos animais (72,6%), sobretudo no período inicial de 7 dias...

The purpose of this study was to produce preliminary methodological standards to allow the use of an intraoral acrylic device adjusted to the palatal mucosa of rats and capable of relining with temporary resilient material (Trusoft) modified with antimicrobial agents in the minimum inhibitory concentrations (MICs) for Candida albicans biofilm. To design this adjustment, parameters were determined in relation to the diet and housing of animals as users of these devices. The total sample (n=115) was divided into six groups: Negative control (NC): without an acrylic intraoral device; Overall Control (OC): device without relining; Positive Control (PC): device relined with Trusoft without the addition of drugs; Chlorhexidine diacetate (CHL): device relined with Trusoft containing chlorhexidine diacetate (0.064 g/mL); Ketoconazole (KET): device relined with Trusoft containing ketoconazole (0.128g/mL); and Nystatin (NYT): acrylic device relined with Trusoft containing nystatin (0.032 g/mL). The animals were sacrificed after 7 or 14 days from the installation ofthe intra-oral devices. The adaptations for obtaining the devices included the impression technique, the reline method and the means of retaining in the palatal mucosa of animals. To obtain the standard descriptive histopathological analysis, criteria had been established in relation to obtaining the histological samples,selecting the region of interest (RI) of analysis and the criteria utilized in the description. It was observed that a paste diet and housing in cages with a wired fence floor with an additional base of wood shavings and craft paper enabled the best possible survival conditions for the animals. The individually made intra-oral devices retained with stainless steel wires at the incisors and molars remained satisfactorily in position throughout the experiment for most animals (72.6%), mainly in the initial period of 7 days. The procedure for the relining of the devices ...

Antimicrobial activity of endodontic sealers based on calcium hydroxide and MTA.

The aim of this study was to evaluate the antimicrobial activity of a new root canal sealer containing calcium hydroxide (Acroseal) and the root canal sealer based on MTA (Endo CPM Sealer), in comparison with traditional sealers (Sealapex, Sealer 26 and Intrafill) and white MTA-Angelus, against five different microorganism strains. The materials and their components were evaluated after manipulation, employing the agar diffusion method. A base layer was made using Müller-Hinton agar (MH) and wells were made by removing agar. The materials were placed into the wells immediately after manipulation. The microorganisms used were: Micrococcus luteus (ATCC9341), Staphylococcus aureus (ATCC6538), Pseudomonas aeruginosa (ATCC27853), Candida albicans (ATCC 10231), and Enterococcus faecalis (ATCC 10541). The plates were kept at room temperature for 2 h for prediffusion and then incubated at 37 degrees C for 24 h. The results showed that Sealapex and its base paste, Sealer 26 and its powder, Endo CPM Sealer and its powder, white MTA and its powder all presented antimicrobial activity against all strains. Intrafill and its liquid presented antimicrobial activity against all strains except P. aeruginosa and Acroseal was effective only against M. luteus and S. aureus.