Antimicrobial activity of conventional and plant-extract disinfectant solutions on microbial biofilms on a maxillofacial polymer surface

In situ study of the effect of endogenous and exogenous agents on color stability, hardness, and surface roughness of an elastomer for facial prostheses

PURPOSE

To evaluate in situ the influence of sweat, oil, sunscreen, and disinfectant solution on the color stability, hardness, and roughness of elastomer for facial prostheses.

MATERIALS AND METHODS

Standardized and intrinsically pigmented specimens remained in contact with human skin from the same person for 30 days, considering exposures (n = 36 per group), absent of exposition (Control, C); sweat and oiliness contact (SO); sweat and oiliness associated with sunscreen (SOS); 0.12% chlorhexidine digluconate immersion (CD0.12%); and all agents exposed (SOSCD). The main variables were color change (CIELab and National Standard Bureau system, NBS), Shore A hardness, and surface roughness, measured at baseline and 30 days. Qualitative analyses were performed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The data were analyzed by Kruskal-Wallis tests (color) and two-way ANOVA (hardness and roughness) with Sidak post-test (α = 0.05).

RESULTS

CD0.12% (1.54 ± 0.49) and SOSCD (2.10 ± 1.03) had similar effects and caused the smallest color changes, considered mild and noticeable (NBS), respectively. SOS promoted the greatest color change (6.99 ± 1.43, NBS: large) and hardness (17.97 ± 0.56); SOS promoted intermediate roughness (3.48 ± 1.05) between SOSCD (2.25 ± 0.53), and two similar groups: C (4.46 ± 0.95), and CD0.12% (4.39 ± 1.26). The qualitative analysis showed an irregular, dense, dry, and whitish layer on the surface of the specimens exposed to sunscreen, which was reduced when in contact with 0.12% chlorhexidine digluconate.

CONCLUSIONS

Endogenous and exogenous factors are capable of altering elastomer properties. The 0.12% chlorhexidine digluconate minimized the changes caused by sweat, oil, and sunscreen.

Evaluation of Mangifera indica, Anacardium occidentale leaf extracts and 0.2% Chlorhexidine gluconate on disinfection of maxillofacial silicone material surface contaminated with microorganisms - An invitro study

Maintenance of the quality and hygiene of maxillofacial prosthesis allows to maintain the health of the residual tissues. Sampling of the maxillofacial prostheses has relieved presence of microbial colonization on silicone surfaces. Cleaning procedures of maxillofacial silicones are done using mechanical means or using adjunctive with chemical means. Cleaning with a 2-4% chlorhexidine gluconate spray or dipping in solution for a minute and then washing under running water can sufficiently condition to reduce the amount of bacterial contamination. Due to rising microorganism resistance and fewer adverse effects, phytoextracts appear to be a viable option. Additionally, the use of excipients derived from plants is provides new opportunities for the pharmaceutical industry into the creation of innovative pharmaceutical products that are sustainable.

Aim

To evaluate and compare the leaf extracts of Mangifera indica (M.indica), Anacardium occidentale(A.occidentale) and 0.2% chlorhexidine gluconate (CHX) on disinfection of maxillofacial silicone material surface contaminated with Staphylococcus aureus (S.aureus) and Candida albicans (C.albicans).

Methods

Of the 150 maxillofacial silicone elastomer silicone samples, 75 samples were contaminated with S. aureus and 75 with C.albicans. The contaminated disc was rolled on blood agar and pre-disinfection Colony Forming Units (CFU) were evaluated followed by subjecting the discs to disinfection protocols. The contaminated discs with S. aureus and C.albicans were disinfected using M.indica leaf extracts, A.occidentale leaf extracts and 0.2% CHX for 10 min. Post-disinfection CFUs were evaluated by rolling the disc on blood agar. The results were tabulated and analysed using dependent t-test, one-way ANOVA and Tukeys multiple posthoc procedure.

Results

Pair-wise comparison of pre-and post-disinfection log CFU counts of S.aureus gave a statistical significance between 0.2% CHX and and M.indica leaf extract. No statistically significant results were found between 0.2% CHX and A.occidentale. Pair wise comparison of the log CFU from pre-disinfection to post-disinfection of C.albicans gave a statistical significance between all the three groups.

Conclusions

In the present study A.occidentale leaf extract and M.indica leaf extract have shown significant reduction in CFU of both the organisms. 0.2% CHX showed the most CFU reduction post disinfection of maxillofacial silicone material surface contaminated S.aureus and C.albicans followed by A.occidentale leaf extracts and M.indica leaf extracts. Given the limitations of the current research, A.occidentale leaf extract and M.indica leaf extract can be used as an alternative for disinfection of maxillofacial silicone prosthesis.

An In Vitro Comparative Evaluation of Conventional and Novel Thymus vulgaris Derived Herbal Disinfectant Solutions against Pathogenic Biofilm on Maxillofacial Silicones and Its Impact on Color Stability

AIM

This study aims to assess the antimicrobial efficacy and impact on color stability of Thymus (T.) vulgaris solution compared to conventional disinfectants on maxillofacial silicones.

MATERIALS AND METHODS

Various solutions were evaluated, including T. vulgaris solutions at 5 and 10%, saline (control), chlorhexidine (4%), and soap water. The substrates were MDX4-4210 silicone elastomers, and the microorganisms tested were Candida (C.) albicans and Staphylococcus (S.) aureus. The viability of microorganisms was determined through an 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) reduction assay, and color stability was measured using a spectrophotometer with X-Rite Europe software. Statistical analysis was performed using the Kruskal-Wallis test, Mann-Whitney U post hoc test, and Wilcoxon Signed Rank test.

RESULTS

Soap water demonstrated superior disinfectant action against both microorganisms, while T. vulgaris solutions at 5 and 10% exhibited comparable antimicrobial efficacy. Chlorhexidine and 10% T. vulgaris solution showed minimal color changes in the silicone material. In contrast, soap water and the 5% T. vulgaris solution resulted in clinically unacceptable color alterations.

CONCLUSION

This study underscores the potential of T. vulgaris as an herbal disinfectant for combating microbial biofilms on maxillofacial silicones, particularly at concentrations of 5 and 10%. The importance of maintaining color stability is emphasized, with Chlorhexidine and the 10% T. vulgaris solution demonstrating effective preservation of esthetics. These findings suggest the viability of considering T. vulgaris as an alternative disinfectant in clinical settings for maxillofacial silicone prostheses.

CLINICAL SIGNIFICANCE

Maxillofacial silicones are vital in restoring aesthetic features for individuals with facial trauma, congenital deformities, or post-surgical interventions. Yet, biofilm-related infections jeopardize their durability and visual integrity. Clinically, T. vulgaris signifies a potential advance in prosthodontic care, offering valuable insights for improving antimicrobial performance and aesthetic durability in maxillofacial prostheses. How to cite this article: Peter M, Kanathila H, Bembalagi M, et al. An In Vitro Comparative Evaluation of Conventional and Novel Thymus vulgaris Derived Herbal Disinfectant Solutions against Pathogenic Biofilm on Maxillofacial Silicones and Its Impact on Color Stability. J Contemp Dent Pract 2023;24(12):967-973.

Antifungal Properties of Essential Oils Derived from the Genus Cymbopogon: A Systematic Review

Essential oils (EOs) are products of secondary metabolism with recognized organoleptic characteristics and biological properties. Recently, there has been a growing demand for EOs in the national and international market, mainly due to the recognition of their use as complementary medicine practices, and the increased use in the industries of pharmaceutics, cosmetics, well-being, veterinary and agroecology, boosting the productive sector. In this context, EOs from grasses of the Cymbopogon (Poaceae) are promising sources of bioactive compounds, due to their recognized biological properties, such as anti-inflammatory, antibacterial, antifungal, antidiabetic, repellent, and larvicide. Thus, the present study aims to carry out a review of the scientific literature of the main works related to the evaluation of the antifungal action of essential oils extracted from plants of the Cymbopogon genus, compiling the species that showed the best results and relating them to their main chemical constituents. This review covers the following species: C. citratus, C. flexuosus, C. winterianus, C. martinii, C. nardus, C. giganteus, C. schoenanthus, C. khasans, and C. proximus. Among them, C. citratus was the most assessed, being associated with the vast majority of studies (61.9 %), and it was also the species that showed the best results in terms of MIC.

Antimicrobial effects of nano titanium dioxide and disinfectants on maxillofacial silicones

STATEMENT OF PROBLEM

Deficient hygiene of maxillofacial prostheses can be a source of infection, and various disinfectants, including nano-oxides, have been suggested for the disinfection of silicone prostheses. While maxillofacial silicones involving nano-oxides at different sizes and concentrations have been evaluated in terms of their mechanical and physical properties, reports are lacking on the antimicrobial effect of nano titanium dioxide (TiO₂) incorporated into maxillofacial silicones contaminated by different biofilms.

PURPOSE

The purpose of this in vitro study was to evaluate the antimicrobial effects of 6 different disinfectants and nano TiO₂ incorporation into maxillofacial silicone contaminated with Staphylococcus aureus, Escherichia coli, and Candida albicans biofilms.

MATERIAL AND METHODS

A total of 258 silicone specimens (129 pure silicones and 129 nano TiO₂-incorporated silicones) were fabricated. Specimens in each silicone group (with or without nano TiO₂) were divided into 7 disinfectant groups (control, 0.2% chlorhexidine gluconate, 4% chlorhexidine gluconate, 1% sodium hypochlorite, neutral soap, 100% white vinegar, and effervescent) in each biofilm group. Contaminated specimens were disinfected, and the suspension of each specimen was incubated at 37 °C for 24 hours. Proliferated colonies were recorded in colony-forming units per mL (CFU/mL). The differences in microbial levels among specimens were evaluated to test the effect of the type of silicone and the disinfectant (α=.05).

RESULTS

Significant difference was found among disinfectants regardless of the silicone type (P<.05). Nano TiO₂ incorporation showed an antimicrobial effect on S aureus, E coli, and C albicans biofilms. Nano TiO₂ incorporated silicone cleaned with 4% chlorhexidine gluconate had statistically less C albicans than pure silicone. Using white vinegar or 4% chlorhexidine gluconate led to no E coli on either silicone. Nano TiO₂ incorporated silicone cleaned with effervescent had fewer S aureus or C albicans biofilms.

CONCLUSIONS

The tested disinfectants and nano TiO₂ incorporation into silicone were effective against most of the microorganisms used in this study.

Disinfectant effects of Brazilian green propolis alcohol solutions on the Staphylococcus aureus biofilm of maxillofacial prosthesis polymers

STATEMENT OF PROBLEM

Brazilian green propolis may be an alternative product that reduces the development of a microbial biofilm on the polymers used for maxillofacial prostheses. However, its effects as a disinfectant have not been fully established.

PURPOSE

The purpose of this in vitro study was to investigate the effects of Brazilian green propolis alcohol solutions against the Staphylococcus aureus biofilm on polymers used in maxillofacial prostheses, the maxillofacial silicone elastomer (MDX4-4210), and specific acrylic resins for ocular prostheses.

MATERIAL AND METHODS

A total of 324 disk-shaped specimens (3×10 mm) of each material were fabricated. All specimens were contaminated with S. aureus (10⁸ cells/mL) to assess the antibiofilm activity of immersion solutions and protocols. Thus, 162 specimens of each material were randomly distributed and equally divided into 5 groups of disinfectants and 1 control group: 3 separate groups of 2.5%, 5%, and 10% propolis alcohol solutions, 1 group of 5% propolis alcohol gel, a positive control group of 2% chlorhexidine gluconate, and a negative control group of distilled water. Specimens (n=9) were disinfected by immersion for 5, 10, and 15 minutes and immersed in culture medium for 24 hours. Any notable turgescence in the final medium was considered indicative of a biofilm. The effects of disinfectants were analyzed by a turbidity assay and by scanning electron microscopy. Data were analyzed descriptively.

RESULTS

The final medium with specimens disinfected with 10% propolis alcohol solution showed no turbidity, indicating constant efficacy against the S. aureus biofilm. Similarly, these findings were observed in the 2% chlorhexidine gluconate group. Scanning electron microscopy images demonstrated that the surface of the polymers treated with 10% propolis alcohol solution did not show bacterial colonies.

CONCLUSIONS

Disinfection with 10% green propolis alcohol solution was effective in eliminating the S. aureus biofilm from specimens of maxillofacial elastomer and N1 acrylic resin specific to ocular prostheses by immersion for 5 minutes.

Chlorhexidine as a Disinfectant in the Prosthodontic Practice: A Comprehensive Review

INTRODUCTION

Controlling the cross-contamination between the dental clinic and laboratory is of utmost importance to maintain the health of dental healthcare personnel (DHCP) and patients. The aim of this paper was to review the current literature with regard to the use of chlorhexidine as a prosthetic disinfectant in prosthodontic practice.

MATERIALS AND METHODS

A scoping review of the literature was performed in Medline/PubMed, Ovid Embase, and the Cochrane Library. A search for all literature published from 1980 to 2021 was based on the following keywords: ['Chlorhexidine/gluconate' OR 'chlorhexidine', OR 'gluconate', OR 'denture disinfectants', OR 'antimicrobial', OR 'disinfectant', OR 'impression disinfectants, OR prosthesis' OR 'biofilm, microbiology'] OR [teeth]. We reviewed the disinfectant in terms of its mechanism of action, antimicrobial effectiveness, disinfection techniques, clinical applications, corrosiveness/damage to the structure of prostheses, and reasonable shelf life.

RESULTS

Chlorhexidine was tested under different concentrations ranging from 0.2 to 5%. It provided a significant reduction in biofilm viability but had a minimum effect on Candida albicans with a variable effect result that showed no significant differences in the dimensional changes by immersion of alginate dental impressions for no more than 10 minutes and no clinically significant dimensional differences on aluwax, polyether, condensation siloxane, and polyvinyl siloxane were noticed. Nonetheless, chlorhexidine altered the surface of the silicone and acrylic resins and affected the long-term hardness of the relining material.

CONCLUSION

Within the limitations of this review, the use of chlorhexidine disinfectant demonstrates a good measure in the reduction of contamination and cross-infection and has a minimal effect on the dimensional stability of most impression materials. Further studies with in-vitro testing are required to confirm these findings.

The antifungal and antibiofilm activity of Cymbopogon nardus essential oil and citronellal on clinical strains of Candida albicans

OBJECTIVE

This study investigated the antifungal and antibiofilm activity of Cymbopogon nardus essential oil (EO) and its major compound, citronellal, in association with miconazole and chlorhexidine on clinical strains of Candida albicans. The likely mechanism(s) of action of C. nardus EO and citronellal was further determined.

MATERIALS AND METHODS

The EO was chemically characterized by gas chromatography coupled with mass spectrometry (GC-MS). The antifungal activity (MIC/MFC) and antibiofilm effects of C. nardus EO and citronellal were determined by the microdilution method, and their likely mechanism(s) of action was determined by the sorbitol and ergosterol assays. Then, the samples were tested for a potential association with standard drugs through the checkerboard technique. Miconazole and chlorhexidine were used as positive controls and the assays were performed in triplicate.

RESULTS

The GC-MS analysis tentatively identified citronellal as the major compound in C. nardus EO. Both samples showed antifungal activity, with MIC of 256 µg/mL, as compared to 128 µg/mL and 8 µg/mL of miconazole and chlorhexidine, respectively. C. nardus EO and citronellal effectively inhibited biofilm formation (p < 0.05) and disrupted preformed biofilms (p < 0.0001). They most likely interact with the cell membrane, but not the cell wall, and did not present any synergistic activity when associated with standard drugs.

CONCLUSION

C. nardus EO and citronellal showed strong in vitro antifungal and antibiofilm activity on C. albicans.

CLINICAL RELEVANCE

Natural products have been historically bioprospected for novel solutions to control fungal biofilms. Our data provide relevant insights into the potential of C. nardus EO and citronellal for further clinical testing. However, additional bioavailability and toxicity studies must be carried out before these products can be used for the chemical control of oral biofilms.

Fungicidal Effect of Lemongrass Essential Oil on Candida albicans Biofilm Pre-established on Maxillofacial Silicone Specimens

Aims:

This in-vitro study aimed to evaluate the efficacy of lemongrass (Cymbopogon citratus) essential oil in eradicating Candida albicans biofilm pre-established on the maxillofacial silicone specimens.

Materials and Methods:

Two maxillofacial silicones, namely, MDX4-4210 and Multisil Epithetik, were used for the fabrication of 6 mm diameter disks (n = 21 for each brand of silicone). A 48-h mature C. albicans ATCC 10231 biofilm was pre-established on sterile silicone specimen. These disks were then exposed to various concentrations of lemongrass essential oil ranging from 0.31% to 5% (v/v), 20% (v/v) nystatin, and RPMI-1640 medium for 18–20 h. After exposure, the remaining viable fungal biofilm was examined by the XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide]-reduction assay. All data were analyzed by using a regression coefficient and a post hoc Tukey HSD multiple comparisons test (α = 0.05).

Results:

Different brands of silicone used for fabrication did not significantly affect the formation of mature C. albicans biofilm (P =0.302). A 5% (v/v) lemongrass essential oil significantly eliminated fungal biofilm by approximately 95% (P =0.031). However, less than 50% of the fungal biofilm was eliminated by the tested oil at a concentration as low as 0.31% (v/v). Furthermore, the fungicidal efficacy against C. albicans biofilm of lemongrass essential oil at 2.5% (v/v) was as potent as that of 20% (v/v) nystatin suspension (P = 0.99).

Conclusion:

Lemongrass essential oil expressed fungicidal effect on C. albicans biofilm pre-established on the disks fabricated from different brands of silicone. Additionally, the fungicidal effectiveness of the oil against the mature fungal biofilm was dose-dependent.

Effects of Dietary Inclusion of Dry Hydrastis canadensis on Laying Performance, Egg Quality, Serum Biochemical Parameters and Cecal Microbiota in Laying Hens

Simple Summary

Extensive studies on alternative sources of feed additives to replace antibiotics are required. Plants of the Ranunculaceae family have been used as medicines or dyes. The representative plant is goldenseal (Hydrastis canadensis), which has a long history of use in North America, with berberine considered the most effective ingredient in goldenseal. Some natural compounds in Hydrastis canadensis function as efflux pump inhibitors and thus may have bactericidal effects against pathogens with antibiotic resistance. However, no conclusive beneficial effects of goldenseal on the livestock industry have been reported. The objective of this study was to examine whether the alternative use of goldenseal roots or leaves has potential health benefits in chickens. Our data demonstrate that Hydrastis canadensis can improve the egg quality and modulate the microbiota composition of laying hens.

Abstract

Alternative growth promoters are able to not only effectively replace the traditional use of antibiotics but also provide additional health benefits for livestock and reduce food safety concerns. This study investigated the effects of dry Hydrastis canadensis on the laying performance and fecal microbial community of laying hens. Twenty-four Lohmann (LSL, white layer strain) hens were reared from 40 to 48 weeks of age and randomly allotted to four dietary treatments (six birds/treatment). The dietary treatments comprised a basal diet with no treatment as control, a basal diet plus 0.6% powder of dry Hydrastis canadensis roots (R) or leaves (L), and a basal diet plus 0.6% powder of a mixture of dry Hydrastis canadensis roots and leaves (1:1, LR). No mortality was observed in the whole experimental period. The results indicated that albumen height in the LR group was significantly greater than that in the control group. The diet supplemented with Hydrastis canadensis had no significant effects on egg production rate, egg weight, eggshell strength, eggshell thickness, Haugh unit, or yolk height during the whole experimental phase. However, principal coordinate analysis, comparative heat map analysis, and cluster dendrogram analysis of cecal microbiota showed distinct clusters among the groups treated with Hydrastis canadensis and the control group. Regarding blood biochemical parameters, serum cholesterol levels were significantly lower in all Hydrastis canadensis-treated groups compared with those in the control group. Moreover, serum low-density lipoprotein levels were lower in hens supplemented with the leaf of Hydrastis canadensis. The abundances of the phyla Fusobacteria and Kiritimatiellaeota were increased (p < 0.05) in laying hens fed with 0.6% Hydrastis canadensis leaves, whereas the abundance of the phylum Firmicutes in cecum digesta decreased in response to treatment with Hydrastis canadensis roots and leaves. The relative abundance of the Fusobacterium genus was higher in the LR group compared with that in the control. On the contrary, we found a different trend in the Synergistes genus. The potential influences of these microbiota on the performance of laying hens were discussed. The results demonstrate that Hydrastis canadensis can improve the egg albumen height and modulate the cecum digesta microbiota composition of laying hens.

Antagonistic effect of isolated and commercially available probiotics on the growth of Candida albicans on acrylic resin denture surfaces

STATEMENT OF PROBLEM

Biofilms can be retained on dental prostheses leading to the development of infections. The indiscriminate use of antifungal drugs can result in the development of microorganisms that are resistant to these antimicrobial agents. Whether probiotics are a suitable alternative for reducing the prevalence of oral candidiasis is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of 6 different live strains of probiotics and 2 commercially available probiotic supplements used for inhibiting the growth of Candida albicans biofilm in heat-polymerized acrylic resin denture base material and to determine whether biofilm byproducts modify the surface of specimens.

MATERIAL AND METHODS

Biofilms of C. albicans were formed on acrylic resin specimens in the presence of probiotics and quantified by colony-forming units (CFUs), and the surface roughness (Ra) of the specimens was assessed before and after the formation of biofilms. The CFU and roughness data were analyzed by analysis of variance and the Tukey HSD test (α=.05).

RESULTS

A significant decrease in the number (CFU/mL) of C. albicans cells was found when they were cultured with 4 probiotics: B. lactis (P=.045), B. longum (P<.001), L. casei (P<.001), and L. helveticus (P<.001) and with the commercially available probiotic Prolive (P=.05). The Ra of specimens decreased after exposure to different microbial biofilms (P≤.05) except in 3 experimental groups.

CONCLUSIONS

In general, the tested probiotics had an antagonistic effect on the growth of C. albicans, and the surface of acrylic resin was altered after exposure to biofilm byproducts.

Dactylorhiza hatagirea (D. Don) Soo: A Critically Endangered Perennial Orchid from the North-West Himalayas

Dactylorhiza hatagirea (Orchidaceae) is a perennial herb inhabiting sub-alpine to alpine regions, ranging at elevations between 2500 and 5000 m.a.s.l. With palmately lobed rhizome and lanceolate leaves having a sheathing leaf base, it bears pink flowers with purple-colored notches and a curved spur. It finds wide use in ayurveda, siddha, unani, and folk medicine in curing disorders of the circulatory, respiratory, nervous, digestive, skeletal, and reproductive systems, besides boosting the immune system to fight infectious diseases. Secondary metabolites such as dactylorhins A–E, dactyloses A–B, and others exhibit a wide spectrum of pharmacological activities (antioxidant, antimicrobial, antiseptic, anticancer, and immune enhancing activities). Its use as a dietary supplement was found to be beneficial in increasing testosterone levels, resulting in improved sexual desire and arousal. Incessant overexploitation of this medicinally important herb has resulted in the dwindling of its populations in the wild, which has resulted in its classification as a critically endangered plant species. Efforts involving mass reproduction through in vitro (through tissue culture) and in vivo (by vegetative propagation) means are currently being made to maintain the germplasm of this critically endangered orchid. Holding immense significance in clinical research and drug discovery, work on the genomic front (transcriptomics) has recently been carried out to discover the wealth of unexplored genetic information for this perennial herb. The present study is aimed at reviewing different aspects of the orchid to present collective (summarized) information on this medicinally important herb in the present, particularly its botany, ethnobotanical uses, phytochemistry, and pharmacognosy, along with the strategies that need to be adopted to prevent its overexploitation in natural habitats.

Antimicrobial effects of photodynamic therapy on Staphylococcus aureus biofilm grown on a specific acrylic resin surface for ocular prostheses

BACKGROUND

Photodynamic therapy (PDT) is a treatment for the specific control of oral biofilms. However, its effects on maxillofacial prostheses have been barely explored. In this study, we evaluated the antimicrobial effect of PDT using methylene blue (MB) and laser against a Staphylococcus aureus biofilm developed on the surface of scleral acrylic resin.

METHODS

Sixty-six specimens of acrylic resin designed for ocular prostheses were fabricated in a disk-shaped format (3 × 10 mm). S. aureus biofilm was grown on the surface of the specimens for 24 h and the disks were then treated with MB at different concentrations (25, 50, 75 or 100 μg/mL), with or without PDT (GaAlAs diode laser; 660 nm; 100 mW; 9 J; 321.4 J.cm^-2; 3.5 W.cm^-2 and 90 s). Control groups were treated with 2% chlorhexidine gluconate (CHX) or phosphate buffered saline. After the treatments, colony forming units (CFU) were counted and the samples were qualitatively evaluated by scanning electron microscopy (SEM). Data were analyzed descriptively and by nested ANOVA and the Tukey test (α = .05).

RESULTS

PDT groups with MB concentrations at 75 and 100 μg/mL formed fewer CFU compared to the other groups (P < 0.001) and the 2% CHX group did not form any CFU. SEM images revealed that the surface of the polymers in these groups did not show bacterial colonies.

CONCLUSIONS

PDT significantly reduced S. aureus biofilm in the scleral acrylic resin when associated with an MB dilution of 75 μg/mL or higher. Thus, PDT can be a promising candidate for disinfecting ocular prostheses.

Antifungal and biofilm inhibitory effect of Cymbopogon citratus (lemongrass) essential oil on biofilm forming by Candida tropicalis isolates; an in vitro study

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (lemongrass) essential oil has been widely used as a traditional medicine and is well known for antimicrobial properties. Therefore, it might be a potent anti-infective and biofilm inhibitive against Candida tropicalis infections. Until now, no ideal coating or cleaning method based on an essential oil has been described to prevent biofilm formation of Candida strains on silicone rubber maxillofacial prostheses, voice prostheses and medical devices susceptible to C. tropicalis infections.

AIM OF THE STUDY

To investigate the antifungal and biofilm inhibitory effects of Cymbopogon citratus oil. Clinical isolates of C. tropicalis biofilms on different biomaterials were used to study the inhibitory effect.

MATERIALS AND METHODS

The efficacy of Cymbopogon citratus, Cuminum cyminum, Citrus limon and Cinnamomum verum essential oils were compared on biofilm formation of three C. tropicalis isolates on 24 well polystyrene plates. C. citratus oil coated silicone rubber surfaces were prepared using hypromellose ointment as a vehicle. The antifungal tests to determine minimum inhibitory and minimum fungicidal concentrations were assessed by a microbroth dilution method and biofilm formation was determined by a crystal violet binding assay.

RESULTS

C. tropicalis strains formed more biofilm on hydrophobic materials than on hydrophilic glass. C. citratus oil showed a high antifungal effect against all C. tropicalis strains. For comparison, C. limon oil and C. cyminum oil showed minor to no killing effect against the C. tropicalis strains. C. citratus oil had the lowest minimal inhibitory concentration of all essential oils tested and inhibited biofilm formation of all C. tropicalis strains. C. citratus oil coating on silicone rubber resulted in a 45-76% reduction in biofilm formation of all C. tropicalis strains.

CONCLUSION

Cymbopogon citratus oil has good potential to be used as an antifungal and antibiofilm agent on silicone rubber prostheses and medical devices on which C. tropicalis biofilms pose a serious risk for skin infections and may cause a shorter lifespan of the prosthesis.

Sealing agent reduces formation of single and dual-species biofilms of Candida albicans and Enterococcus faecalis on screw joints at the abutment/implant interface

The aim of this research was to evaluate the efficacy of a commercial sealing agent at the abutment/implant interface against microleakage of single and dual-species biofilms of Candida albicans and Enterococcus faecalis into external hexagon (EH) and Morse taper (MT) prosthetic connections. A total of 216 samples of implants and their abutments were tested. Six groups (n = 36) were evaluated based on biofilm and period of incubation (7 and 14 days). The implant connections EH and MT (n = 18) were divided according to the use of the material (n = 9) (EH-T and MT-T: with the sealing agent; EH-C and MT-C: control). The biofilms were analyzed by microbial counting (CFU/mL) and SEM analysis and photographs of the material in the screw joints were also taken. Data were analyzed by Student t test, two-way ANOVA and Bonferroni test. For the single-species biofilms, there was a significant reduction in the growth of E. faecalis when compared MT-C and MT-T or EH-C and EH-T at 7 and 14 days. The same was observed for C. albicans biofilms. For dual-species biofilms of E. faecalis and C. albicans, the sealing agent was more effective in preventing microbial infiltration into the MT connection at 14 days, while microbial infiltration did not occur into EH connections even in absence of the sealing agent for both periods of evaluation. Overall, these data suggest that the presence of the sealing agent reduces or eliminates the microleakage of E. faecalis and C. albicans biofilms into the implants regardless of the period of incubation.

Classification, History, and Future Prospects of Maxillofacial Prosthesis

This review presents a classification system for maxillofacial prostheses, while explaining its types. It also aims to describe their origin and development, currently available materials, and techniques, predicts the future requirements, and subsequently discusses its avenues for improvement as a restorative modality. A literature search of the PubMed/Medline database was performed. Articles that discussed the history, types, materials, fabrication techniques, clinical implications, and future expectations related to maxillofacial prostheses and reconstruction were included. Fifty-nine articles were included in this review. Maxillofacial prostheses were classified as restorative or complementary with subclassifications based on the prostheses finality. The origin of maxillofacial prostheses is unclear; however, fabrication techniques and materials have undergone several changes throughout history. Currently, silicones and acrylic resins are the most commonly used materials to fabricate customized prostheses. Maxillofacial prostheses not only restore several types of orofacial defects but also improve the patients' quality of life. Although the current clinical scenario concerning the field of maxillofacial prostheses is promising, improvements in material quality and techniques for maxillofacial prostheses may be expected in the future, to produce better results in the treatment of patients.

Mechanical and Morphological Effect of Plant Based Antimicrobial Solutions on Maxillofacial Silicone Elastomer

The objective of this study was to determine the effect of plant based antimicrobial solutions specifically tea tree and Manuka oil on facial silicone elastomers. The purpose of this in vitro study was to evaluate the effect of disinfection with plant extract solution on mechanical properties and morphology on the silicone elastomer. Test specimens were subjected to disinfection using tea tree oil, Manuka oil and the staphylococcus epidermidis bacteria. Furthermore, a procedure duration was used in the disinfection process to simulate up to one year of usage. Over 500 test specimens were fabricated for all tests performed namely hardness, elongation, tensile, tear strength tests, visual inspection and lastly surface characterization using SEM. A repeated measures ANOVA revealed that hardness and elongation at break varied significantly over the time period, whereas this was not observed in the tear and tensile strength parameters of the test samples.

Effects of trimethylsilane plasma coating on the hydrophobicity of denture base resin and adhesion of Candida albicans on resin surfaces

STATEMENT OF PROBLEM

Candida-associated denture stomatitis is the most common oral mucosal lesion among denture wearers. Trimethylsilane (TMS) plasma coating may inhibit the growth of Candida albicans on denture surfaces.

PURPOSE

The purpose of this in vitro study was to investigate whether TMS plasma coatings can effectively reduce C albicans adhesion on denture base acrylic resin surfaces.

MATERIAL AND METHODS

Sixty denture base acrylic resin disks with smooth and rough surfaces were prepared and were either left untreated (control group) or coated with TMS monomer (experimental group) by using plasma. Contact angles were measured immediately after TMS plasma coating. The morphology of C albicans adhesion was observed with scanning electron microscopy (SEM). Energy-dispersive spectroscopy (EDS) was used to characterize the elemental composition of the specimen surface. An adhesion test was performed by incubating the resin disk specimens in C albicans suspensions (1×10⁷ cells/mL) at 37°C for 24 hours and further measuring the optical density of the C albicans by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay test. One-way ANOVA and 2-way ANOVA were followed by a post hoc test analysis (α=.05).

RESULTS

The group with TMS coating exhibited a more hydrophobic surface than the control group. EDS analysis revealed successful TMS plasma coating. The difference in the mean contact angles between the uncoated group and the TMS-coated group was statistically significant (P<.05), 79.0 ±2.9 degrees versus 105.7 ±1.5 degrees for the smooth surface and 90.2 ±7.6 degrees versus 131.5 ±2.1 degrees for the rough surface. In SEM analysis, the C albicans biofilm was found to grow more on the surface of the denture base resin without the TMS coating than on the surfaces of the experimental group. In the adhesion test, the amount of C albicans adhering to the surface of denture base resin with the TMS coating was significantly less than that on the surfaces without TMS coating (P<.05).

CONCLUSIONS

TMS coating significantly reduced the adhesion of C albicans to the denture base resin and may reduce denture stomatitis.