ABSTRACT
ZrO2 nanoparticles (ZNPs) have excellent physical properties. This study investigated the fracture load of implant-supported, fixed cantilevered prosthesis materials, reinforced with ZNPs and various polymerization techniques, compared with conventional and CAD/CAM materials. Sixty specimens were made from two CAD/CAM; milled (MIL) (Ceramill TEMP); and 3D-printed (NextDent Denture 3D+). Conventional heat-polymerized acrylic resin was used to fabricate the other specimens, which were grouped according to their polymerization technique: conventionally (HP) and autoclave-polymerized (AP); conventionally cured and reinforced with 5 wt% ZNPs (HPZNP); and autoclave reinforced with 5 wt% ZNPs (APZNP). The specimens were thermocycled (5000 cycles/30 s dwell time). Each specimen was subjected to static vertical loading (1 mm/min) using a universal Instron testing machine until fracture. Scanning electron microscopy was used for fracture surface analyses. The ANOVA showed significant fracture load differences between all the tested groups (p = 0.001). The Tukey post hoc tests indicated a significant difference in fracture load between all tested groups (p Ë 0.001) except HP vs. HPZNP and AP vs. MIL. APZNP had the lowest mean fracture load value (380.7 ± 52.8 N), while MIL had the highest (926.6 ± 82.8 N). The CAD/CAM materials exhibited the highest fracture load values, indicating that they could be used in long-term interim prostheses. Autoclave polymerization improved fracture load performance, whereas ZrO2 nanoparticles decreased the fracture load performance of cantilevered prostheses.
ABSTRACT
The antifungal effect of zirconium dioxide nanoparticles (ZrO2NPs) incorporated into denture base material has been inadequately investigated; additionally, to the authors' knowledge, no studies have assessed the influence of artificial aging on the antifungal activity of these particles. Methodology. Heat-polymerized acrylic resin disks were fabricated and divided into four groups (0%, 1%, 2.5%, and 5% ZrO2NPs by weight). Antifungal activity was assessed using the direct culture and disk diffusion methods. Surface roughness and contact angles were measured using a profilometer and a goniometer, respectively. The artificial aging procedure was performed by repeating all tests at 7, 14, and 30 days following 2 rounds of thermocycling. Data were analyzed using ANOVA and Tukey's post-hoc test (p < 0.05). Results. The addition of ZrO2NPs significantly decreased the adhesion of Candida albicans with and without artificial aging procedures (p < 0.001), while the disk diffusion methods did not reveal inhibition zones. ZrO2NP-modified specimens displayed significantly higher surface roughness compared to specimens in the control group (p < 0.05) and showed the same behaviors with artificial aging procedures. The contact angle was significantly decreased in all modified groups in comparison to the control group (p < 0.05). Conclusion. The addition of ZrO2NPs to polymethylmethacrylate denture base material reduced the adhesion of Candida albicans with a long-term antifungal effect. With the addition of ZrO2NPs, contact angles were decreased and surface roughness was increased; 1% was the most appropriate concentration. Clinical significance. The addition of ZrO2NPs to denture base material confers a long-term antifungal effect and could be used as a possible method for preventing and treating denture stomatitis.
ABSTRACT
The experimental bioactive sealers were synthesized by incorporating fluoridated-nano-bioactive glass (F-nBG; 2.5 and 5wt%) in AH Plus® (Dentsply DeTrey, Konstanz, Germany) sealer and denoted as AH-FBG2.5 and AH-FBG5, respectively. Structural pattern, setting time, flowability, and water sorption analysis were performed. The fluoride release behavior was evaluated periodically over the course of 40 days using inductively coupled plasma optical emission spectroscopy. For sealing ability, post-extraction single-rooted teeth were obturated with sealers. The percentage of voids and sealing ability were evaluated periodically using micro-computed tomography (micro-CT) followed by push-out bond strength. The Fourier transform infrared spectra showed a change in peak height with an increase in the concentration of fillers. The setting time, flowability, and water sorption of experimental groups were within the acceptable clinical range. The fluoride release, sealing ability, and bond strength of experimental sealers were significantly high. The experimental sealers have potential to overcome sealing ability issues of sealers.
Subject(s)
Root Canal Filling Materials , Epoxy Resins , Fluorides , X-Ray MicrotomographyABSTRACT
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.
