Current perspectives and the future of Candida albicans-associated denture stomatitis treatment.

Denture stomatitis (DS) is a multifactorial disease, but the proliferation of Candida albicans (C. albicans) is the main causative factor. Different modalities have been suggested for the prevention and treatment of DS. Among the different approaches that have been implemented to inhibit and control DS there are the topical application of antifungal agents, the surface modification of the denture base and the incorporation of antimicrobial agents into the denture base material. Antifungal agents can effectively control DS, but the recurrence of the disease is common. Accordingly, it has been suggested that coating the surface of the acrylic denture base may result in a decreased fungal adhesion. In recent years, nanotechnology has dominated the research, and several nanoparticles have demonstrated antifungal effects. Therefore, the aim of this article was to review the antifungal effects of the different methods that have been suggested for the prevention and/or control of DS as well as the antimicrobial activity of denture base acrylic resin additives, including nanoparticles. Studies reporting the incorporation of antifungal/antimicrobial agents into the polymethyl methacrylate (PMMA) denture base were included in this review. The PubMed, Web of Science, Google Scholar, and Scopus databases were searched for the articles published between January 2000 and December 2018 using the following key words: dental prosthesis, denture stomatitis, candidiasis, antifungal agents, biofilm formation, polymethyl methacrylate, and PMMA. The antimicrobial material incorporated into the resin may have a superior effect in preventing DS over simply coating the surface of the denture base. However, some antimicrobial fillers can have adverse effects on the physical and mechanical properties of the denture base resin.

Effect of SiO2 Nanoparticles Addition on the Flexural Strength of Repaired Acrylic Denture Base.

OBJECTIVE: The objective of this study was to evaluate the effect of nano-SiO2 addition on the flexural strength (FS) of repaired acrylic denture base. MATERIALS AND METHODS: Heat-polymerized acrylic resin specimens were fabricated in dimensions of (65 × 10 × 2.5 ± 0.1 mm3 ) and then sectioned and prepared, creating repair gap with butt (90 degrees) and bevel (45 degrees) repair surface designs forming two main groups according to joint design. Further subdivision was done into four groups (n = 10) according to nano-SiO2 concentration: one unmodified group and three modified groups (0.25, 0.5, and 0.75 wt %) in the autopolymerized repair resin. Each pair of a specimen was assembled in a mold and repaired according to manufacturer's recommendations. STATISTICAL ANALYSIS: Three-point bending test was done to measure FS, followed by scanning electron microscope (SEM) examination for fracture surface analysis. Data were analyzed using ANOVA and Tukey's post hoc test (α = 0.05). RESULTS: The addition of nano-SiO2 significantly improved FS of repaired acrylic resin in comparison to the unmodified group (p ˂ 0.05). For butt joint, significant differences between nano-SiO2 reinforced groups were noticed (p ˂ 0.05), while reinforced beveled groups did not differ significantly (p ˃ 0.05). Bevel design remarkably increased FS compared with butt design per respective filler concentration. From the SEM images, improved FS was presented with a homogeneous distribution of nano-SiO2 within polymethyl methacrylate. CONCLUSION: Nano-SiO2 addition to repair resin and 45 degree-beveled repair surface increased FS of repaired acrylic resin.

Comparative study of some mechanical properties of cobalt chromium and polyether ether ketone thermoplastic removable partial denture clasps: an In-vitro Study / Estudo comparativo de algumas propriedades mecânicas dos grampos parciais removíveis termoplásticos removíveis termoplásticos de cobalto cromo e éter cetona: um estudo in vitro

Objective: was to evaluate the retentive force, fatigue resistance and deformity of clasps made from two materials cobalt chromium and poly ether ether ketone (PEEK). Material and Methods: sixteen models were fabricated,each one having lower 1st molar. Models were divided into two groups according to materials,group I (GI) for cobalt chromium (Co-Cr) and group II (GII) for PEEK. Each testing models and its clasps were mounted inside universal testing machine, the retention was measured by applying withdrawal force to it by this machine at 5 mm/min. The Fatigue resistance is measured by the reduction in retention through repeated insertion and removal cycles using robota chewing simulator. Removal and insertion cycling of clasps was carried out for 360, 730, 1080, 1,440, 2,116 and 2,880 cycles (corresponding to 3, 6, 9, 12, 18 and 24 months of simulated clinical use of a RPD) to simulate the fatigue resistance test. Deformity was measured before and after each cycling using a digital micrometer. Statistical analysis was done by 2-way-ANOVA test to detect significance effects of each variable. Results: Retention and fatigue resistance, after 360, 730, 1080, 1,440, 2,116 and 2,880 cycles totally the difference between Co-Cr and PEEK groups was statistically non-significant (P = 0.0980> 0.05) where (Co-Cr > PEEK). Deformation results, regardless to evaluation time, Co-Cr group recorded statistically significant higher deformation mean value than PEEK group (P = 0.008 < 0.05).Regardless to material group, deformation mean value changed nonsignificantly by time (P = 0.2882> 0.05). Conclusion: PEEK clasps (1.0 mm in cross section diameter) engage 0.50 mm undercut provide sufficient retention nearly similar that of Co-Cr clasps.(AU)

Objetivo: o objetivo foi avaliar a força de retenção, a resistência à fadiga e a deformidade dos grampos fabricados com dois materiais diferentes: cromo-cobalto (Co-Cr) e poliéter-éter-étercetona (PEEK). Materiais e métodos: dezesseis modelos foram confeccionados, cada um com 1º molar inferior. Os modelos foram divididos em dois grupos de acordo com o material: grupo I Co-Cr e grupo II para PEEK. Cada modelo de teste universal e seus grampos foram montados em uma máquina de teste universal. A retenção foi medida aplicando força de retirada por esta máquina a 5 mm/min. A resistência à fadiga foi medida pela redução na retenção através de ciclos repetidos de inserção e remoção usando um simulador do ciclo de mastigação. O ciclo de remoção e inserção dos grampos foi realizado por 360, 730, 1080, 1.440, 2.116 e 2.880 ciclos (correspondendo a 3, 6, 9, 12, 18 e 24 meses de uso clínico simulado de um RPD) para simular o teste de resistência à fadiga. A deformidade foi medida antes e após cada ciclo, usando um micrômetro digital. A análise estatística foi realizada pelo teste ANOVA de 2 fatores para detectar os efeitos de significância de cada variável. Resultados: A retenção e a resistência à fadiga após 360, 730, 1080, 1.440, 2.116 e 2.880 ciclos entre os grupos Co-Cr e PEEK não mostrou diferença estatisticamente significativa (p = 0,0980> 0,05), onde (Co-Cr> PEEK). Para os resultados da deformação, independentemente do tempo de avaliação, o grupo Co-Cr registrou um valor médio de deformação maior, com diferença estatística significativa, quando comparado com o grupo PEEK (p= 0,008 < 0,05). Independentemente do grupo de material, o valor médio da deformação foi alterado de forma não significativa pelo tempo (p= 0,2882> 0,05). Conclusão: os grampos PEEK (1,0 mm de diâmetro da seção transversal) engatam 0,50 mm retenção quase semelhante à dos grampos Co-Cr (AU)

In vitro assessment of the antifungal effects of neem powder added to polymethyl methacrylate denture base material.

BACKGROUND: Denture with antimicrobial activities is desirable to prevent Candida albican adhesion subsequently decreasing the susceptibility of denture stomatitis incidence. Azadirachta Indica, commonly known as Neem powder has antimicrobial effect but the effect of its addition to acrylic denture base on C. albicans adhesion has not been investigated. The aim of this study was determine whether adding neem powder to acrylic denture base materials could reduce Candida albicansadhesion. MATERIAL AND METHODS: One hundred and twenty acrylic resin denture specimens were fabricated and divided into heat-polymerized (n=60) and auto-polymerized (n=60) groups. Each group was further divided into 6 groups (n=10) based on the neem concentration: 0, 0.5, 1, 1.5, 2 and 2.5 wt% of the polymer. After polymerization, the specimens were polished, stored in distilled water, sonicated, sterilized, submerged in artificial saliva containing C. albicans, and finally, placed in an incubator at 37°C. Slide counting and direct culture methods were used to assess the antifungal effects of the neem addition. An analysis of variance and post hoc Tukey's test were performed for the data analysis (p≤0.05 was statistically significant). RESULTS: Based on the results, the neem addition significantly decreased the C. albicans count when compared to the control group (p≤0.05). Moreover, the count decreased as the neem concentration increased (lowest count with 2.5 wt%). CONCLUSIONS: The results suggest that adding neem powder to acrylic resin denture base materials reduces the adhesion of C. albicans; therefore, the incorporation of neem could be a possible denture stomatitis prevention method. Key words:Denture stomatitis, Candida albicans, Azadirachta indica, neem powder, denture base.