Resilient liner modified by antimicrobials for denture stomatitis treatment: A randomized controlled trial.

OBJECTIVES: This randomized clinical trial evaluated the effectiveness of an interim denture resilient liner (Trusoft) modified with minimum inhibitory concentrations (MICs) of antimicrobial agents for Candida albicans biofilm in the denture stomatitis (DS) treatment. METHODS: Forty participants with DS and maxillary complete denture (MCD) wearers were randomly assigned to one of the treatments for 14 days (n=10): nystatin oral suspension (Control-100,000IU/mL; 4 × /day), MCD relined with Trusoft either without (Tru) or with nystatin (Ny) or chlorhexidine diacetate (Chx) at MICs. Cytological smears and mycological quantitative cultures were taken from the palate and denture before treatment (baseline), at the end of treatment (day 14), and at follow-up (days 30, 45, and 60). Photographs of the palate were made at each visit. Data were analyzed by the Cochran and χ2 tests, ANOVA and the Tukey test or the Friedman and Kruskal-Wallis tests (α=0.05). RESULTS: Palatal smears of the Ny and Chx groups exhibited no mycelial Candida (0%) on day 14, and, at the 60-day follow-up, it was observed for only 1 participant from Chx group. MCD smears showed reduction in mycelial forms for all groups on day 14 (P<0.05), but this difference was maintained at follow-up only for the relined dentures (P<0.05). Unlike Tru and the control groups, Ny and Chx groups evidenced a significant reduction in CFU/mL values and DS severity throughout the trial (P<0.05). CONCLUSIONS: The addition of nystatin and chlorhexidine at MICs to an interim resilient liner is a promising treatment for DS, with better results than those for conventional therapy with nystatin suspension, including the follow-ups. CLINICAL SIGNIFICANCE: Compared with conventional topical antifungal therapy, modifying a denture reline material with antimicrobials provided a therapeutic option for denture stomatitis. This non-invasive, straightforward therapeutic approach can be easily adopted by dentists and has the advantage of not requiring patient compliance while maintaining therapeutic concentrations on the denture base.

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.

Considerações sobre os tipos de próteses parciais removíveis e seu impacto na qualidade de vida / Considerations on types of removable partial dentures and their impact on oral health

O objetivo deste estudo foi discutir, por meio de uma revisão de literatura, as indicações, contraindicações, vantagens, desvantagens das alternativas reabilitadoras mais comuns utilizando PPRs e o impacto desses tratamentos na qualidade de vida relacionada à saúde bucal dos pacientes. Foi realizada uma pesquisa ampla na literatura, com a utilização dos termos "Prótese Parcial Removível", "Qualidade de Vida", "Saúde bucal"; "Satisfação do Paciente", no período entre 1990 e 2018, no Medline, Google Scholar, internet e livros didáticos. Foi demonstrado que a reabilitação com PPRs associadas a implantes resultou em melhor qualidade de vida associada à saúde bucal dos usuários, seguida por PPRs retidas por encaixe e PPRs convencionais. Entretanto, o profissional deve considerar as condições sistêmicas, bucais e econômicas de cada paciente, tendo o conhecimento biomecânico bem como a ciência dos benefícios e das desvantagens de cada tipo de tratamento para estabelecer um correto diagnóstico do caso e, assim, indicar o melhor tipo de PPR. Dessa forma, é possível oferecer o melhor tratamento para cada paciente parcialmente edêntulo, devolvendo estética e função de maneira satisfatória de modo a resultar em maior nível de satisfação e qualidade de vida(AU)

The purpose of this study was to discuss, through a review of the literature, indications, contraindications, advantages, disadvantages of the most common rehabilitation alternatives using RPDs and the impact of these treatments on patients' oral health quality of life. A broad research was conducted in the literature, using the terms "Partial Removable Prosthesis", "Quality of Life", "Oral Health"; "Patient Satisfaction" in the period between 1990 and 2018, in Medline, Google Scholar, internet and textbooks. It was demonstrated that rehabilitation with RPDs associated with implants resulted in a better oral health quality of life of users, followed by RPDs with attachments and conventional RPDs. However, the professional should consider the systemic, oral and economic conditions of each patient, based on the biomechanical knowledge, as well as the science of the benefits and disadvantages of each type of treatment to establish a correct diagnosis of the case, and thus, indicate the best type of RPD. In this way, it is possible to offer the best treatment for each partially edentulous patient, returning aesthetics and function in a satisfactory manner in order to result in a higher level of satisfaction and quality of life(AU)

Determining acceptable limits for water sorption and solubility of interim denture resilient liners.

STATEMENT OF PROBLEM: Specifications for determining acceptable limits of water sorption (WS) and solubility for interim denture resilient liners are lacking. PURPOSE: The purpose of this in vitro study was to evaluate the WS and solubility of interim resilient materials throughout their lifespans. MATERIAL AND METHODS: Specimens (n=10) of 7 tissue conditioners, Coe-Comfort (CC), Softone (ST), Rite-Line (RL), Dura Conditioner (DC), Hydrocast (HC), Dentusoft (DS), and Visco-gel (VG) and 2 interim resilient liners, Trusoft (TS) and Coe-Soft (CS), were submitted to desorption until weight stabilization. Next, they were immersed in distilled water at 37°C for 3, 5, 7, or 14 days and then weighed, dried, and reweighed. Data (%) were analyzed using 2-way ANOVA and the Tukey honestly significant difference (HSD) test (α=.05). RESULTS: VG demonstrated the highest WS (12.06 ±0.93%-16.62 ±0.87%) and solubility (20.30 ±4.26%-23.59 ±2.24%; P<.05) percentages. Low WS values were presented by CC (2.23 ±0.53%-2.99 ±0.49%; P<.05). The WS showed no significant changes for CC, CS, and TS over 14 days (P>.05). SL presented intermediate solubility values (4.09 ±1.60%-8.80 ±1.15%), and the other materials showed values lower than 3.35 ±0.70%. CC, DC, DS, HC, RL, TS, and CS showed no changes in solubility throughout the 14-day trial. CONCLUSIONS: Over the lifespan of a tissue conditioner (7 days), CC, RL, DC, HC, DS, CS, and TS presented suitable in vitro performance. Among the tested materials, CC, CS, and TS were considered best suited for denture relining for up to 14 days.

Efeito do desafio ácido nas propriedades superficiais das camadas externa e interna de dentes acrílicos reforçados / Effect of acid challenge on the surface properties of external and internal layers of cross-linked acrylic teeth

Introdução: Os dentes acrílicos artificiais devem apresentar característica de resistência aos ácidos, a fim de assegurar a manutenção de suas propriedades, ao longo de sua vida útil. Entretanto, não há estudos disponíveis na literatura pertinente sobre as propriedades superficiais de dureza e rugosidade das diferentes camadas de resina acrílica que compõem os dentes artificiais submetidos a ensaios de erosão simulada. Objetivo: Avaliar a dureza e rugosidade superficiais das camadas externa e interna de dentes artificiais acrílicos reforçados submetidos a desafio ácido. Metodologia: Molares (SR Postaris e Trilux) seccionados transversalmente foram avaliados inicialmente quanto à dureza Vickers e rugosidade. Esses ensaios foram repetidos após metade das amostras de cada tipo de dente (n=10) ser imersa em água destilada (controle) e outra metade em vinagre durante 15 min/dia por 28 dias. Os resultados foram analisados por ANOVA 2-critérios e teste de Tukey (α=0,05). Resultado: A dureza inicial da camada externa dos dois diferentes tipos de dente não sofreu alteração significativa pelo desafio ácido (p>0,05) e a imersão em vinagre não causou efeito deletério à dureza inicial da camada interna dos dois tipos de dentes avaliados (p>0,05). Após 28 dias, a rugosidade inicial de ambos os tipos de dentes estudados, para as duas camadas, não foi alterada com água ou vinagre (p>0,05). Conclusão: Os dentes acrílicos reforçados foram resistentes ao desafio ácido uma vez que suas camadas interna e externa não apresentaram alteração significativa de dureza e rugosidade superficiais.

Introduction: Artificial acrylic teeth must be resistant to acids for ensure the maintenance of their properties throughout their useful life. However, there are no studies available in the literature about the surface properties of hardness and roughness of the different layers of acrylic resin that make up the artificial teeth submitted to simulated erosion tests. Objective: To evaluate the surface hardness and roughness of external and internal layers of artificial cross-linked acrylic teeth submitted to acid challenge. Methodology: First molars (SR Postaris and Trilux) transversely sectioned had its Vickers hardness and roughness initially evaluated. These tests were repeated after half of the tooth samples (n=10) be immersed into distilled water (control) and half in vinegar during 15 min/day for 28 days. Data were analyzed using 2-way ANOVA and Tukey's test (α=0.05). Result: The initial external layers hardness of both was not significantly altered by acid challenge (p> 0.05) and the immersion in vinegar caused no deleterious effect on the initial internal layers hardness of the two tested teeth (p>0.05). After 28 days, the initial roughness of both teeth evaluated for the two layers was not affected by water or vinegar (p>0.05). Conclusion: The reinforced acrylic teeth were resistant to acid challenge since its internal and external layers showed no significant change in hardness and surface roughness.

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.

Efeito antimicrobiano residual e citotoxidade in vitro de resina acrílica para base de prótese após imersão prolongada em agentes de limpeza / In vitro residual antimicrobial effect and cytotoxicity of acrylic resin base prosthesis after long-term immersion in cleaning agents

O presente estudo in vitro objetivou avaliar a longo prazo o potencial antimicrobiano residual e a citotoxicidade de soluções químicas de limpeza de prótese quando incorporadas à resina acrílica termopolimerizável após sucessivos ciclos de imersão noturna diária. Discos (10mm x 1mm) de resina acrílica termopolimerizável para base de prótese (Lucitone 550) foram submetidos a três ciclos diários de desinfecção (8h/cada) em hipoclorito de sódio a 1% (NaClO), digluconato de clorexidina a 2% (CLX) ou água destilada (controle) durante 91 (T91) ou 183 dias (T183), simulando o período de 9 meses ou 1,5 ano de imersão noturna diária realizada pelo paciente. Inicialmente, foi utilizado o método de concentração inibitória mínima em caldo para determinar o possível efeito residual (incorporação) das soluções à resina acrílica. Metade dos discos imersos em cada agente de limpeza em um dos tempos de imersão (n=5) foi inoculada (1x107cels/mL) com um dos patógenos associados à estomatite protética: Candida albicans (Ca) e Staphylococcus aureus (Sa). Os discos foram incubados a 37oC para análise em espectrofotômetro após 24h, 7 e 14 dias. Os valores de absorbância foram convertidos em porcentagens de inibição microbiana. Confirmada a ação antimicrobiana residual dos agentes de limpeza incorporados à resina acrílica, foi então analisada sua citotoxicidade in vitro sobre fibroblastos gengivais humanos (L929). Os efeitos citotóxicos foram avaliados por meio do ensaio colorimétrico MTT [brometo de 3-(4,5-dimetiltiazol-2-yl)-2,5-difeniltetrazólio] para a determinação da viabilidade celular, após as células serem expostas por 24h às amostras de cada condição experimentais (n=18) previamente imersas em uma das soluções por um dos períodos avaliados (T91 ou T183). A citotoxicidade foi determinada com base na atividade mitocondrial em relação a corpos de prova não submetidos à imersão nas soluções testadas. Os resultados do ensaio do MTT foram analisados estatisticamente por ANOVA...

This in vitro study aimed to evaluate the long-term residual antimicrobial activity and cytotoxicity of chemical denture cleansers incorporated into a heat-polymerized acrylic resin after successive cycles of daily overnight soaking. Discs (10mm x 1mm) were prepared from heat-polymerized acrylic resin (Lucitone 550) and submitted to three daily immersion (8h/each) in 1% sodium hypochlorite (NaClO), chlorhexidine digluconate 2% (CHX) or distilled water (control) for 91 days (T91) or 183 days (T183), simulating the period of 9 months or 1.5 year of nocturnal immersion performed by the patient. Initially, the method of minimum inhibitory concentration in broth was used to determine the possible residual effect (incorporation) of the acrylic resin solution. Half of the disks immersed in each cleaning agent for one of the period immersion (n=5) was inoculated (1x107cells/mL) with pathogens associated with denture stomatitis: Candida albicans (Ca) or Staphylococcys aureus (Sa). The disks were incubated at 37oC for analysis in a spectrophotometer after 24h, 7 and 14 days. The absorbance values were expressed as percentages of microbial inhibition. Confirmed the residual antimicrobial action of cleaning agents incorporated into the acrylic resin, its cytotoxicity was analyzed in vitro on human gingival fibroblasts (L929). Cytotoxic effects were evaluated by the colorimetric assay MTT [3- (4,5- dimethylthiazol-2-yl) -2,5-diphenyl tetrazolium bromide] to determine cellular viability after the cells were exposed for 24h to the samples of each experimental condition (n=18) previously immersed in one of the solutions for the evaluation periods (T91 or T183). Cytotoxicity was determined based on mitochondrial activity compared to the specimens not subjected to immersion in the solutions. The MTT assay results were 1-way ANOVA followed by Tukey's HSD post-hoc test (a=0.05). For the periods T91 and T183, no microbial inhibition was observed with immersion in water...