Acrylic Soft Liners Research Articles

In vitro analysis of a novel dimethylaminododecyl methacrylate modification of dental acrylic soft liner material

Soft denture liners have limitations like short lifespan and increased microbial buildup. Despite promise as a non-leaching antimicrobial polymer in dentistry, the impact of dimethylaminododecyl methacrylate (DMADDM) on soft liner performance remains unexplored. This study aimed to evaluate the effect of integrating different concentrations of DMADDM to cold cure acrylic resin soft liner, on its antimicrobial activity, cytotoxicity, and physical properties. The same properties were compared to a conventional commercially available denture soft liner. The study employed a control group (conventional soft liner) and three test groups containing 3.3%, 6.6%, and 10% (total mass fraction) DMADDM, respectively. Antimicrobial activity against Candida albicans and Streptococcus mutans was assessed through colony counts and biofilm biomass. Cytotoxicity was evaluated using an oral epithelial cell line. Additionally, wettability and hardness were measured to assess physical properties. Incorporation of DMADDM significantly reduced Candida albicans and Streptococcus mutans counts, and biofilm biomass, compared to the control. Additionally, DMADDM improved the soft liner's wettability and mitigated long-term hardness increase. In conclusion, DMADDM holds promise in enhancing soft liner performance. However, careful selection of its optimum concentration is crucial to ensure both safety and efficacy for future clinical use.

A Temporary Acrylic Soft Denture Lining Material Enriched with Silver-Releasing Filler-Cytotoxicity, Mechanical and Antifungal Properties.

Colonization of temporary denture soft linings and underlying tissues by yeast-like fungi is an important clinical problem due to the negative influence on the process of prosthetic treatment. Typical hygienic procedures are often insufficient to prevent fungal infections, so in this study, an antimicrobial filler (silver sodium hydrogen zirconium phosphate) was introduced into acrylic soft liner at concentrations of 1, 2, 4, 6, 8 and 10% (w/w). The effect of this modification on antifungal properties against Candida albicans, cytotoxicity, Shore A hardness, tensile strength and tensile bond strength, sorption and solubility was investigated, considering the recommended 30-day period of temporary soft lining use. The most favorable compilation of properties was obtained at a 1 to 6% filler content, for which nearly a total reduction in Candida albicans was registered even after 30 days of sample storing. The tensile and bond strength of these composites was at the desired and stable level and did not differ from the results for the control material. Hardness increased with the increasing concentration in filler but were within the range typical for soft lining materials and their changes during the experiment were similar to the control material. The materials were not cytotoxic and sorption and solubility levels were stable.

Evaluation of Effect the Incorporation of The Virgin Coconut Oil on Thermal Conductivity of Heat-Cure Acrylic Soft Denture Lining Materials

Background: The main disadvantage of soft liners is the low thermal conductivity between the denture base and soft liner material.Aim: The present study aims to estimate the impact of adding virgin coconut oil (1.5% vol and 2.5% vol) to a soft acrylic liner material in a thermal conductivity test.Material and Methods: For this project, we did 30 pieces of acrylic soft liner material. The specimens were divided into three groups: 10 control group specimens that only contained the soft liner material, 10 specimens mixed with virgin coconut oil at a volume of 1.5% with the soft liner material, and 10 specimens mixed with virgin coconut oil at a volume of 2.5% with the soft liner material. Equipment in the Technologies, Department used to conduct thermal conductivity tests. 40mm diameter and 2.5mm thickness thermal conductivity specimens were prepared.Results: Using static analysis, data showed that the soft liner with the highest thermal conductivity contained virgin coconut oil at a volume of 2.5% compared to the soft liner containing virgin coconut oil at a volume of 1.5%, and the control group, the results revealed p < 0.01.Conclusion: Thermal conductivity is increased when virgin coconut oil (2.5% by volume) is incorporated into the soft acrylic liner material.

Evaluation of the Antifungal Activity of Heat-Cured Soft Denture Liner Impregnated with Chitosan Nanoparticles

The most serious problem of the resilient denture lining materials is colonization and penetration of the soft-liner surface by Candia albicans and related Candida species. So, this research was oriented to check the antifungal effect of Chitosan nanop articles (CHs NPs) incorporated into heat-cured acrylic soft liners. 60 specimens were prepared, 30 specimens for disk diffusion test and other 30 specimens for viable count of C. albicans test. The specimens split into six groups depending on different percentages of Chitosan NPs addition: 0.5wt%, 1.5wt%, 2.5wt%, 3.5wt%, 4.5wt%, and control group withou t addition 0%). For disk diffusion test, the autoclaved soft lining samples were fitted into sterilized Petri dish containi ng Mueller Hinton agar upon which candidal suspension were swabbed then fitted the samples on the agar surface, in cubated for 24 hrs. Then the inhibition zones were measured by utilizing digital caliper ruler. For viable count test, t he autoclaved samples of soft liner were submersion in sterilized tubes containing Sabouraud dextrose broth in which a small amount of candidal suspension, incubated for 24hrs. The Results of the disk-diffusion test showed the highest mean value of the inhibition zone at 3.5wt% group follow ed by 4.5wt% group and there was no inhibition zone for control and other experimental groups. Furthermore, the vi ability test indicated the colony forming units of C. albicans were decrease as the percentage of CHs NPs increased. With limitation of this study, it was concluded the CHs NPs considered as a strong antifungal agent and the impregnation of the chitosan nanoparticles into soft liner that help to form a soft lining material with antifungal activity and minimal candida associated infection.

Evaluation The Effect of Incorporation of Different Herbal Extract Powders (Either Neem or Aloe Vera) On Thermal Conductivity and Shear Bond Strength of Acrylic Soft Denture Liner Material

The main drawbacks of the soft liners were poor thermal conductivity and poor bonding between denture base and soft lining. The purpose of this study was to analysis the influence of incorporating either Neem or Aloe Vera on thermal conductivity and shear bond strength of heat cure acrylic soft liner. Sixty heat cure acrylic soft liner specimens were prepared and classified as two major groups based on tests that evaluated (thermal conductivity and shear bond strength), each major group sub classified for three groups based on incorporated material: The control group (10) specimens, (10) specimens with 10% by weight of Neem powder; (10) specimens with 10% by weight of Aloe Vera powder. Thermal conductivity specimens were fabrication with dimensions of (40 mm diameter × 2.5 mm thickness). Two acrylic block of shear bond strength specimens with dimensions (75mm × 25mm × 5 mm length, width, depth respectively) was fabrication. The reline material application on space between two acrylic blocks. The (Lee disc) equipment was used to assess thermal conductivity. With a crosshead speed of 0.5mm/min, a shear bond strength was measured. Data statically analyzed by One-way ANOVA and LSD tests. The results showed the Neem group had highest mean value of thermal conductivity and shear bond strength than aloe Vera and control groups at p<0.01. Either Neem or Aloe Vera increased thermal conductivity and shear bond strength of soft liner.

The Effect of Various Disinfection Methods on The Tensile Bond Strength of Soft Lining Material

Disinfection of dentures and resilient denture liners were preferred for cross-contamination treatment and better safety. Nevertheless, it has been found that these techniques affect the physical and mechanical properties of denture liners. Objective: To evaluate the impact of various disinfection methods on the tensile bond strength of acrylic soft liner. Material and Methods: 25 samples were made, then divided randomly into five groups (4 disinfection groups as well as a control group), after the daily disinfection procedure, distilled water was used to store the samples at room temperature. After 30 days, a universal testing device (Gester, China) was used to assess the tens ile bond strength. The machine applied force to the specim ens at a crosshead constant speed of 5 mm/minute until failure was recorded. Statistics software (SPSS) was used to analyze the measurements. Results: After 30 days of regular ex posure to different disinfection methods, a greater mean value for bond strength showed in the control group while the lesse r value was in the chlorhexidine group. No significant difference was found between the control and Protefix tablet groups. The sodium hypochlorite and microwave groups had no significant difference between them, but they were significantly different from the control, Protefix tablet, and chlorhexidine groups. the chlorhexidine group was significantly different from the control and other disinfected groups. Conclusion: All disinfected soft liners revealed a decrease i n tensile bond strength, which was not significant with the protefix cleansing tablet but significant with the chlorhexidine, sodium hypochlorite, and microwave regimes.

Effect Of Incorporation Of Either Neem Or Aloe Vera Powders On Tear Strength And Hardness Of Acrylic Soft Denture Liner Material

Aim of the study: The heat acrylic soft lining materials are far from ideal due to poor soften and weak tearing strengths. This cause some practical problems when testing the adherence of soft liners to denture bases. The study objective was to assess the effect of either Neem or Aloe Vera extracts on tear strength and hardness of heat acrylic soft denture lining material.
 Materials and methods: Sixty acrylic soft liner specimens were prepared and divided into two main groups (30 specimens for tear strength test, 30 specimens for hardness test). These main groups sub-divided into three groups, each one consist of 10 specimens, according to incorporated material. The hardness specimens were fabrication with dimensions of (30 mm diameter × 3 mm thickness). The tear strength specimens were fabricated according to ASTM specification D-624. The scanning electron microscope (SEM) was used to estimate the distribution of either Neem or Aloe Vera particles within the soft liner. Energy dispersive X-ray spectroscopy (EDS) was used to analysis the elements of studied materials. Tear strength specimens were measured by utilizing universal Instron machine. Hardness specimens were measured by utilizing Shore A durometer. Statically all data were analyzed by using SPSS software.
 Results: The outcomes showed non-significant differences (p>0.05) of all studied groups in tear strength and a highly significant (p<0.001) decrease in hardness of all studied groups in comparison with the control group.
 Conclusion: Incorporation of Neem or Aloe Vera extracts powders showed slight increases in tear strength and highly significant decreases in hardness of soft liner material.

Antifungal Activities and Some Surface Characteristics of Denture Soft Liners Containing Silicon Dioxide Nanoparticles.

ABSTRACTObjective:This study aimed at determining the influence of adding silicon dioxide nanoparticles (nano-SiO2) to soft relining materials on C. albicans adhesion, surface roughness, and contact angle.Materials and Methods:Eighty heat-polymerized acrylic resin disks were constructed and relined by using auto-polymerized acrylic soft liners (COE-SOFT, GC Co., Tokyo, Japan). The specimens were categorized into two groups according to the tests conducted. Group A was composed of 40 specimens for evaluating antifungal activity, and Group B was composed of 40 specimens for testing surface roughness and contact angle. Each group was subcategorized into four subgroups (n = 10) according to the concentration of nano-SiO2 added to the soft-liner powder: control, 0.25%, 0.5%, and 1.0% by weight. The colony forming unit (CFU) was used to assess C. albicans count. A profilometer was used to measure the surface roughness values (Ra; μm). The sessile drop method was used to evaluate the contact angle (o) by using a goniometer. Analysis of variance and Tukey’s post hoc tests (α = 0.05) were used for the data analysis.Results:In comparison with the unmodified group, the 0.25% and the 0.5% nano-SiO2 groups exhibited significantly lower C. albicans counts (P < 0.001), surface roughness (P < 0.001), and contact angles (P < 0.001). The exception was the 1% group, which exhibited higher C. albicans count, surface roughness, and contact angles than lower-concentration nano-SiO2 groups; however, these values in the 1% group were still less than their respective values in the control group.Conclusion:The addition of 0.25% and 0.5% nano-SiO2 to an auto-polymerized acrylic soft liner decreased C. albicans adhesion, surface roughness, and contact angle.

Effect of Thermocycling on Surface Roughness and Shear Bond Strength of Acrylic Soft Liner to the Surface of Thermoplastic Acrylic Treated with Ethyl Acetate

Objective: To enhance bonding strength between thermoplastic denture base and acrylic soft liner through ethyl acetate surface treatment.Materials and Methods: Modifications of thermoplastic acrylic denture base surface were investigated with SEM. FTIR was used to detect whether there was a chemical bond between thermoplastic acrylic and the organic solvent. A total of 80 samples were prepared and divided into 20 samples for the surface roughness test and 60 samples for the shear bond strength test. Failure type was assessed visually.Results: Shear bond strength and surface roughness values of un treated samples were lower in comparison to surface treated groups; the greatest post thermocycling bond strength value was recorded for the samples treated with ethyl acetate following 1500 cycles.Conclusions: Bonding strength was improved following ethyl acetate surface treatment.

EFFECT OF DENTURE CLEANSERS ON HARDNESS OF ACRYLIC SOFT LINER

Plasticizer is the content of the soft liner (with soft acrylic polymer (poly ethylmethacrylate)) or denture tissue conditioner material that maintains the soft said material. However, it will release as a result of the saliva or water solution being absorbed that could be effected on the acrylic soft liner physical properties such as a hardness. Selection of the denture cleanser is very important to minimize its impact, which is the traditional plant cinnamon (Cinnamomum burmani) can be used as an alternative of natural denture cleansure agents besides alkaline peroxide chemicals used frequently. The aim of this study was to determine the effect of different denture cleansers on hardness of acrylic soft liner. Method: Eighteen cylindrical acrylic soft liner samples (15mm x 10 mm (ASTM: D-2240 64T)) were divided into 3 groups : group I aquadest immersion, group II alkaline peroxide immersion and group III cinnamon immersion. The measurement of acrylic soft liner hardness was done using Shore A hardness D2240 after 7 days of immersion. The results were submitted to one-way ANOVA and post hoc Bonferroni. Results: The highest average of acrylic soft liner hardness was shown by alkaline peroxide immersion group followed by cinnamon immersion group and aquadest immersion group sequentially. There was a significant difference between all groups (p&lt;0.05). Conclusion: There was effect of different denture cleansers on hardness of acrylic soft liner. Keywords: soft liner, denture cleanser, cinnamon

Antifungal property of acrylic denture soft liner containing silver nanoparticles synthesized in situ

ObjectivesDenture soft liner is applied to relieve pain from candida-induced denture stomatitis and promote healing, but with shortage of antifungal activity and easily harbors fungi. To overcome this problem, the in-situ method was used to synthesize silver nanoparticles (AgNPs) in acrylic soft liner to obtain antifungal effects. MethodsAcrylic soft-liner with various weight percentage of silver 2-ethylhexanoate (0%, 0.1 %, 0.2 %, 0.3 %) were prepared in 10 mm × 10 mm × 3 mm. After chemical polymerization, the diameter of AgNPs synthesized in situ and the degree of conversion of each group were measured. After 3, 7, and 14 days of storage in water, the antifungal rate (AFR) of in vitro direct contact antifungal assays and the antifungal test of non-cumulative extract solution were measured respectively. The release profiles of silver ions from the specimen within 14 days were also evaluated. ResultsEvenly distributed AgNPs (4.7 nm–5.3 nm) were observed, and the degree of conversion had no significant difference among these groups. The AFR increased as the silver concentration rose, while decreasing with the storage time. After 14 days of water storage, the AFR of 0.2 % and 0.3 % groups still reached 63.38 % and 75.51 %, respectively. The non-cumulative extract solution had no antifungal effect. ConclusionsWithin the service life, the acrylic soft liner containing AgNPs synthesized in situ had effective control of Candida albicans through direct contact. Clinical SignificanceThis study suggests that AgNPs synthesized in situ may be an effective strategy in modifying acrylic denture soft liner to treat and prevent denture stomatitis.

Shear Bond Strength of Acrylic Soft Liner after Incorporation of Silver-Zinc Zeolite

Shear Bond Strength of Acrylic Soft Liner after Incorporation of Silver-Zinc Zeolite

Evaluation of Tensile Bond Strength of Heat‑Polymerized Acrylic Soft Liners with Various Surface Pre‑Treatment of Denture Bases: An In Vitro Study

Evaluation of Tensile Bond Strength of Heat‑Polymerized Acrylic Soft Liners with Various Surface Pre‑Treatment of Denture Bases: An In Vitro Study

Is immersion in mint oil or apple vinegar solution a valid antifungal approach for acrylic soft liners?

ObjectivesIn-vitro assessment of the validity of immersion in mint oil or apple vinegar solutions as antifungal approach for acrylic soft liners. Materials and methodsSixty disc-shaped specimens: 9 mm in diameter and 2 mm in length, and sixty cylinders: 12.5 mm in diameter and 20 mm in length of Vertex-Dental Heat-cured acrylic soft liner were prepared for antifungal activity and resilience measurements respectively. Specimens were divided into three groups; twenty in each, for immersion in mint oil, apple vinegar and distilled water (control). The groups were divided into four subgroups, five in each, for the different immersion periods: one day, one week, three weeks and six weeks. For each group, the daily immersion protocol was 8 h of immersion in the testing solution followed by 16 h in artificial saliva. This was repeated for each immersion period. Antifungal activity was assessed using disc diffusion method by measuring the inhibition zone for each disc twice: after 24 and 48 h incubation. Modulus of resilience was determined using a universal testing machine, where a stress-strain curve was obtained for each specimen and the area under the elastic portion of the curve was calculated. ResultsA significantly higher antifungal activity was revealed following immersion in mint oil compared to apple vinegar solution. The immersion period was a significant variable for the antifungal activity measured after 24 h following immersion in either solution whereas it was an insignificant variable for the antifungal activity measured after 48 h following immersion in apple vinegar solution. A significant reduction in the antifungal activity was noted as the incubation period was increased from 24 to 48 h except after six weeks immersion in apple vinegar solution. Modulus of resilience of the acrylic soft liner was adversely affected by immersion in mint oil solution for more than one day and in apple vinegar solution for more than one week. ConclusionsMint oil and Apple vinegar represent possible natural antifungal immersion solutions for acrylic soft liner provided that the immersion protocol is implemented properly.

Comparison of effectiveness of silver zeolite as an antimicrobial agent in acrylic and silicone soft liners in complete denture patients: An in vivo study

BACKGROUND: Soft liners (SLs) are easily colonized and infected by Candida species and bacteria, leading to denture-induced stomatitis. Hence, it is essential that the SLs be taken care of. To serve such a purpose, antimicrobial zeolites have been incorporated. Limited in vitro evidence suggests that silver zeolite (SZ) is a potentially effective antimicrobial agent. Hence, this study aims to analyze and compare the antimicrobial effectiveness of SZ when added to two different types of SLs in vivo for 28 days in complete denture patients. MATERIALS AND METHODS: This study was undertaken to determine the efficacy of SZ as an antimicrobial agent when incorporated in acrylic soft liners (ASLs) and silicone soft liners (SSLs). A total of 32 edentulous patients were selected and were divided into two groups. Group 1 consisted of 16 patients, wherein SSL was used, and Group 2 consisted of 16 patients with ASL. The reduction of colony-forming units (CFUs) was seen in both the groups after an interval of 28 days. RESULTS: There was a greater reduction noted when SZ was incorporated in SSLs after 28 days. Group 1 showed a mean reduction of CFU from 4.60 to 1.98, whereas Group 2 showed a mean reduction from 4.73 to 3.39. Thus, SZ was effective in both the SLs. CONCLUSION: SZ showed a significant reduction in CFU in both the SLs. Hence, this in vivo study concluded that incorporation of SZ is effective as an antimicrobial agent when added to SLs.

Influence of surface characteristics on the adhesion of Candida albicans to various denture lining materials

Objective. This study evaluated the influence of surface characteristics of various denture lining materials on the adherence of Candida albicans. Materials and methods. Four different types of materials (tissue conditioners, acrylic and silicone soft liners and hard reline materials) were selected. Disk-shaped material specimens were prepared and their surface roughness values (Ra) measured using a profilometer. The contact angles of four reference liquids were measured on the material surfaces and surface energy parameters (total surface energy, acid and base components, degree of hydrophobicity/hydrophilicity) of the materials were calculated in accordance with acid-base theory. Specimens were incubated with C. albicans and adhering fungi quantified using the colony counting method. Data were statistically analyzed using a one-way ANOVA with Games–Howell post-hoc test (α = 0.05). Pearson correlation analysis was applied to detect correlations between surface characteristics and Candida adhesion. Results. Significant differences in the surface roughness of the materials were found (p < 0.001). The acrylic soft liners were more hydrophilic than the other materials. Overall, the acrylic soft liners and tissue conditioners showed significantly greater Candida adhesion than silicone soft liners and hard reline materials (p < 0.05). The Pearson correlation analysis indicated that the base component and degree of hydrophobicity/hydrophilicity of the materials (p = 0.005/0.008), rather than the total surface energy and the surface roughness (p = 0.093/0.057), affected C. albicans adherence in a statistically significant way. Conclusions. The adhesion of C. albicans to denture lining materials can be accounted for in terms of interfacial acid-base interactions.

A Comparative Study to Evaluate The Softness of Heat Processed and Auto Polymerized Denture Relining Materials When Stored in Hard and Soft Water-An Invitro Study

ABSTRACT Aim To evaluate the effect of hard and soft water on softness of three commercially available soft liners. Material and Methods 8 specimens of 3mm height and 41mm diameter were fabricated from each soft liner on acrylic resin base of 3mm height and 44mm diameter. The specimens were stored in artificial saliva (Wet mouth, ICPA product) for14 hours in a day, at 37°C in an incubator and the rest of the time 4 specimens from each group were stored in hard water and 4 in soft water. Softness of each specimen was recorded using Shore-A durometer at the end of 1st, 7th, 15th, and 30th day. Results When compared between hard and soft water, the autopolymerized acrylic and autopolymerized silicone soft liners had significant reduction in softness on 7th day in hard water. The autopolymerized acrylic soft liner had least softness in both hard and soft water. The heat polymerized acrylic soft-liner showed maximum softness in both hard and soft Water. Conclusion Heat polymerized acrylic soft liner was proven to be softer than the other two materials followed by autopolymerized silicone and autopolymerized acrylic soft liners.

Changes in surface roughness and colour stability of soft denture lining materials caused by denture cleansers.

Soft denture lining materials were immersed into solutions of denture cleansers for 8 h at room temperature, and immersed into distilled water for the remainder of the 24-h period at 37 degrees C. Surface roughness of the soft denture lining materials was measured by contact type surface roughness instrument. For the colour stability test, soft denture lining materials were immersed in the denture cleansers as described above for 180 days. Finally, the colour changes of each material were quantitatively measured by a photometrical instrument to obtain the colour differences between newly processed specimen and immersed specimens (P < 0.01). An autopolymerizing silicone material, Evatouch, exhibited severe changes in surface roughness by all denture cleanser, and the generic material GC Denture Relining showed the minimal changes. Severe colour changes were also observed with some liner and cleanser combinations (P < 0.01). Except for Evatouth, the four silicone soft liners were more stable in surface roughness and in colour change than the two acrylic soft liners. One autopolymerizing silicone (GC denture relining) and one heat curing silicone (Molloplast B) demonstrated the best stability.

A mechanical analysis of the physical bonding properties of soft lining materials to PMMA

The bonding properties of soft liners to acrylic denture bases are characterized by their variable resistance to external loading. This resistance depends on the nature of the load, the chemistry and mode of polymerization of the liner, and the topography of the acrylic surface to which the liner is applied. The results obtained indicate that heat-curing acrylic soft liners are superior to silicone rubber materials; and that light smoothing of the acrylic surface prior to processing the liner has a beneficial effect on bonding.