Genomic identification of microbial species adhering to maxillofacial prostheses and susceptibility to different hygiene protocols

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.

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.

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.

A Literature Review on Biofilm Formation on Silicone and Poymethyl Methacrylate Used for Maxillofacial Prostheses

Silicone elastomers are considered the most suitable maxillofacial materials for extraoral prostheses to date due to their superior physicochemical properties. The aim of this review was to describe the characteristics of biofilm formation on silicone and polymethyl methacrylate used for maxillofacial prostheses and review different strategies of biofilm management for silicone maxillofacial prosthesis. A structured literature search was conducted using the following databases - PubMed, Google Scholar, ScienceDirect, LILACS, IndeMED, OVID, EMBASE, NIH Clinical Trials - for reports related to the biofilms. English language articles were only included in the study. Biofilms induced various systemic infections if they are not treated at an early stage. Biofilms are formed due to various reasons like fungal, bacterial and mixed infections of the patient and also due to prosthetic appliances. The manual or mechanical pressure physically removes the biofilm and most biofilm molecules from surfaces. Treatment must be given with utmost caution and concern irrespective of the presence or absence of biofilm. With regards to the materials used for fabricating maxillofacial substitutes, it has been defined that both acrylic resin and silicone may harbour microorganisms, however, the larger porosities in silicone make it vulnerable to microbial adhesion. The major limitations of these materials are that they have numerous porosities on their surface and, along with the modification of the anatomy of the facial tissues as a result of the lesion, may compromise the natural balance of the microbial flora, favouring microbial colonization and formation of biofilms.

Evaluation of Antimicrobial and Antibiofilm Activities of Copper Oxide Nanoparticles within Soft Denture Liners against Oral Pathogens

OBJECTIVES

Soft denture liners provide a favorable environment for adhesion and colonization of microorganisms. This in vitro study aimed to examine the efficacy of different concentrations of copper oxide nanoparticles (CuO NPs) incorporation into soft denture liner on the biofilm formation of the microbial species.

METHODS

Field Emission Scanning Electron Microscopy (FESEM) images from NPs were recorded. Antifungal susceptibility testing of CuO NPs against five standard strains of Candida albicans (CBS 10261, 1905, 1912, 1949, 2730), Streptococcus mutans (ATCC35668), Streptococcus sobrinus (ATCC27607), and Streptococcus salivarius (ATCC9222) was performed by the broth microdilution method with the Clinical and Laboratory Standards Institute reference method. The biofilm inhibition percentages of CuO NPs on the soft denture liners were determined by XTT assay.

RESULTS

The characterization of CuO NPs by scanning electron microscope (SEM) analyses confirmed the synthesis of NPs with appropriate structure and size with a mean diameter of 18.3 ± 9.1 nm. The CuO NPs successfully inhibited the growth of the tested standard strains of C. albicans and Streptococcus spp. at concentrations ranging from 64 to 128 µg mL-1. Indeed, incorporation of CuO NPs at a concentration of 500 µg mL-1 into the soft denture liners exhibited a significant activity (75%) in inhibition of C. albicans. biofilm formation in a dose-dependent manner. The biofilm formation of C. albicans in the presence of CuO NPs was lower than Streptococcus spp. in comparison with the control group (p < 0.05).

CONCLUSION

Incorporation of CuO NPs significantly decreased the colonization and plaque formation of the oral pathogens, especially C. albicans accumulation. These NPs may be useful as a promising agent for the antimicrobial management of soft denture liner materials.

Efficacy of incorporating silver nanoparticles into maxillofacial silicone against Staphylococcus aureus, Candida albicans, and polymicrobial biofilms

STATEMENT OF PROBLEM

The presence of biofilms on maxillofacial silicone increases the risk of infections and reduces durability. Whether silver nanoparticles (AgNPs) with potent antimicrobial effects help reduce biofilm formation is unclear.

PURPOSE

The purpose of this in vitro study was to assess the antimicrobial effect of sub 10-nm AgNPs in maxillofacial silicone against Staphylococcus aureus, Candida albicans, and mixed species biofilms containing both and to test the effectiveness of different AgNP concentrations against all 3 biofilms in vitro.

MATERIAL AND METHODS

Silicone disks (M511; Technovent Ltd) containing 0.0% (control), 0.1%, and 0.5% AgNPs were fabricated and treated with S. aureus, C. albicans, and mixed species strains of both in 24-well culture plates containing appropriate media. Each well received a 0.1-mL aliquot of the standardized suspension of microorganisms. The plates were incubated for 21 consecutive days, and colony-forming units per milliliter (CFU/mL) were measured on the first, third, fifth, seventh, fifteenth, and twenty-first day with the Miles and Misra method. Data were analyzed by 2-way ANOVA and the paired t test to evaluate the relationship between AgNP concentration, microbial strain, and time (α=.05). Mean CFU/mL differences for each time and for each biofilm category were assessed by repeated measure ANOVA.

RESULTS

AgNPs decreased the mean CFU/mL in both concentrations compared with the control. The 0.1% concentration showed sustained efficacy throughout the test, while the 0.5% concentration had high efficacy initially with a gradual decrease. However, the results were inconsistent for the mixed biofilm. The paired sample t test at day 3 and 15 and day 3 and 21 showed statistically significantly different results (P<.001) in all but 1 group in the 0.5% concentration. The 2-way mixed ANOVA showed statistically significant (P<.001) interaction between AgNP concentration and time in all groups. The 1-way ANOVA of AgNP concentrations was statistically significantly different (P<.001) for all time points. A statistically significant (P<.001) effect of time on CFU/mL was found for all the AgNP concentration groups in all 3 biofilms.

CONCLUSIONS

Silicone elastomers with sub 10-nm AgNPs displayed antimicrobial properties in vitro against S. aureus, C. albicans, and mixed species strains. AgNPs (0.1%) were effective against both microbial strains and can provide a baseline for further long-term studies regarding antimicrobial efficacy, silver ion leaching, and cellular internalization. Mixed species biofilm needs further exploration with standardized study parameters.

The challenge of managing oral maxillofacial rehabilitation with quality and cost-benefit

Although orofacial cancer leads to substantial functional, esthetic, and psychosocial deficits for patients, reconstructive plastic surgeries may not be indicated for large facial defects. The high costs of prosthetic oral maxillofacial rehabilitation may hamper such treatment, which commonly involves virtual planning, craniofacial implants, and computer-aided design and computer-aided manufactured prostheses. This report shows the treatment of 2 patients with large facial defects from surgical resection of cancerous tissue who were rehabilitated with implant-supported bar-clip overdentures and facial prostheses fabricated by using low-cost straightforward methods.

Analysis of physical properties of facial silicones with different pigmentations submitted to nonthermal plasma treatment and accelerated aging

STATEMENT OF PROBLEM

Exposure of silicone prostheses to environmental factors can alter their properties, affecting longevity. However, whether nonthermal plasma (NTP) can prevent these alterations is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the surface roughness (Ra), sorption, solubility, and color stability (ΔE₀₀) of the MDX4-4210 and A-120 silicones, with and without NTP treatment in accordance with an independent analysis of the use of 2 pigmentations.

MATERIAL AND METHODS

One hundred sixty specimens were fabricated and distributed into 16 groups (n=10) as per the silicone, pigmentation, and NTP coating. The NTP was applied, and the Ra, sorption, solubility, and ΔE₀₀ were evaluated before and after accelerated aging. ANOVA was used, and the HSD Tukey test was applied (α=.05).

RESULTS

NTP generated an increase in roughness after aging, regardless of pigmentation or silicone. A-120 silicone without NTP showed a reduction in roughness after aging, regardless of pigmentation. For sorption and solubility, the bronze pigmentation (for A-120 and MDX4-4210) presented the smallest results after NTP treatment. For MDX4-4210 with pink pigmentation and NTP, sorption decreased and solubility increased. For A-120 with pink pigmentation and NTP, sorption and solubility increased. Sorption was reduced in all situations, except for A-120 with pink pigmentation, which increased. Regardless of the silicone used, solubility was reduced after NTP for bronze pigmentation. For A-120 and MDX4-4210 with pink pigmentation and NTP, the solubility increased. For both pigmentations, the NTP treatment promoted lower color alteration only for the A-120 silicone after accelerated aging (within the acceptability threshold).

CONCLUSIONS

The NTP protocol of this study, which was applied to facial silicones, generated inconsistent results between the evaluated properties. Therefore, the NTP protocol used does not seem to be ideal for the treatment of silicone surfaces after aging.

In vitro evaluation of the effect of different disinfectants on the biofilm of Staphylococcus epidermidis and Staphylococcus aureus formed on acrylic ocular prostheses

The aim of this study was to evaluate the effect of disinfectants on the biofilm of Staphylococcus aureus and Staphylococcus epidermidis formed on the acrylic surface of ocular prostheses. In this study, 396 acrylic specimens were manufactured (50% for Staphylococcus epidermidis, and 50% for Staphylococcus aureus). For each bacterium, 66 specimens were subjected to biofilm formation on their surfaces for 24 hours, 66 specimens were subjected to biofilm formation on their surfaces for 48 hours, and 66 specimens were subjected to biofilm formation on their surfaces for 72 hours. Then, they were divided into groups according to disinfection method (n = 6): sterile distilled water for 10, 15, 30 min, and 6 hours (control); soap for 30 min (NES30); Opti-Free for 30 min (OPF30) and 6 h (OPF6); Efferdent for 15 min (EFF15); and 0.5%, 2%, and 4% chlorhexidine for 10 min (0.5% CHX10, 2% CHX10, and 4% CHX10). After the treatments, the specimens were vortexed to release the biofilm and the counting of bacterial colonies was performed (CFU/mL). Three-way ANOVA and the Tukey-Kramer HSD test were used (α = 0.05). For Staphylococcus epidermidis, there was no significant difference between NES30, OPF30, and OPF6 with their respective control groups; nor between NES30, OPF30, and OPF6 themselves, regardless of the biofilm development period (P >0.05). For Staphylococcus aureus, there was no significant difference between NES30 and OPF30 with their control group; nor between NES30 and OPF30 themselves, regardless of the biofilm development period (P >0.05). For Staphylococcus aureus, OPF6 showed a significant reduction in the number of CFU/mL when compared with its control group, NES30, and OPF30, regardless of the biofilm development period (P <0.05). For both bacteria, 0.5% CHX10, 2% CHX10,4% CHX10, and EFF15 showed a significant reduction in the number of CFU/mL when compared with their control groups, NES30, OPF30, and OPF6, regardless of the biofilm development period (P <0.05). Therefore, EFF15 and CHX (0.5%, 2% and 4%) were effective in reducing Staphylococcus epidermidis and Staphylococcus aureus on acrylic surfaces. NES30 and OPF (30 and 6) are not recommended.