Soft Denture Lining Materials Research Articles

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.

Effectiveness of Chitosan versus Natural Aloe Vera on Candida Adherence in Denture Soft Lining Material.

Soft denture lining materials act as a cushion between the denture base and tissues. Alongside having many advantages, its main problem is candida growth due to its rubbery and porous texture. Many interventions have been performed to halt the growth of candida within soft lining materials such as the use of antifungal therapy and strict oral and denture hygiene but there are consequences such as recurrence, drug resistance, and toxicity related to these interventions. Since natural agents such as aloe vera and chitosan have been proven to have antibacterial and antifungal properties with minimum adverse effects, this study aimed to study the effectiveness of chitosan and aloe vera powders incorporated within denture soft lining materials against candida adherence. Methodology. A total of 60 soft-lining material samples were prepared that were equally divided into three groups, viz., group 1 (chitosan incorporation), group 2 (aloe vera incorporation), and group 3 (control). Candida was obtained from the microbiology lab to form a candidal suspension, diluted in 0.9% NaCl to match the McFarland standard bacteriologic solution. Samples were incubated at 37°C for 24 hours in test tubes containing 100 mL of the candidal suspension and 9.9 mL of the previously prepared Sabouraud dextrose agar. Crystal violet stain was used to stain the adhering cells by fixing them with methanol 80%. For each sample, the adhering candida cells were counted on three standard fields by using an inverted light microscope, and the mean of those fields was recorded. The mean value for samples containing aloe vera was 41.15, while the mean values for samples containing chitosan and the control group were 16.05 and 79.1, respectively. Of all the three groups, aloe vera powder had a significant efficacy against candida growth as compared to the chitosan and control groups (P value = 0.001). Both herbal agents were effective against candida growth. In comparison, aloe vera was more effective against candida growth compared to chitosan.

An assessment of the impact of L.Salvadora persica and G.Tea on the surface roughness and hardness of heat-cured acrylic-based denture soft liners.

Background: Soft denture liners are a type of dental prosthesis that functions as a cushioning material, alleviating the stress induced by the act of chewing. They offer relief to persons who encounter discomfort when wearing complete or partial dentures, particularly when these dentures are situated on rigid surfaces that support the denture. The objective of this study: is to assess the effects of including L.Salvadora persica. and green tea (G.Tea) extract powders on the surface roughness and hardness characteristics of acrylic-based soft liners. Materials & Procedures: 30 specimens were constructed using wax molds and acrylic-based heat-cured denture soft lining material. The standard curing procedure was used. The samples were separated into three equal groups: group A, the control group, with no additives in the soft-liner material; group B, with 5.12% weight percept L.salvadora persica extract powder; and group C, with 5.12% weight present green tea (G.Tea) extract powder. The samples were then prepared for surface hardness and roughness testing. Results: The results revealed that there was a non-significant rise in the mean values of surface roughness for both group B and group C, group B having the highest mean values followed by group C. When compared to the control group, the results showed a considerable rise in the mean values of surface hardness in group (B), which had the highest mean value for surface hardness, followed by group (C). Conclusion: The results of this study indicate that the incorporation of L.salvadora persica at a concentration of 1.024g and green tea (G.Tea) extract powders at a concentration of 1.024g shown a positive impact on the surface hardness of denture soft lining materials

Comparative Evaluation of Hardness and Energy Absorption of Some Commercially Available Chairside Silicone-Based Soft Denture Liners and a Heat-Cured Soft Denture Liner.

To investigate the hardness and energy absorption of four commercially available chairside types of silicone materials and compare their properties with heat-cured silicone material. The chairside materials investigated were GC reline soft, mucopren soft, sofreliner soft and elite soft relining. The heat-cured polymer silicone material was Molloplast B. All soft lining materials were processed according to manufacturers' instructions. Two properties were investigated. Ten specimens for each test were prepared for each soft liner except for the water absorption and solubility test, for which only five specimens were prepared. The specimens of energy absorption (10 × 10 × 3 mm) were tested using a Lloyd instruments testing machine. Hardness specimens (38 × 38 × 3) were tested using a shore A durometer and were divided into two subgroups; dry and wet storage. The specimens of energy absorption (10 × 10 × 3 mm) were tested using a Lloyd instruments testing machine. Sofreliner soft was significantly softer than Molloplast B. GC reline soft was significantly harder than molloplast B. At high loads, sofreliner soft and elite soft relining was significantly more resilient than molloplast B. Mucopren soft was significantly stiffer than Molloplast B. At low loads, all materials showed similarities in stiffness and resilience; the difference between them was insignificant. After one month of immersion, GC reline and mucopren significantly increased hardness values. In all conditions and at all four-time points, the hardness values for GC Reline soft were the greatest, and hardness values for Sofreliner Soft were the least. Some chairside soft denture lining materials could have similar significant properties to molloplast-B, such as sofreliner soft and elite.

Effect of Water Sorption and Solubility on Two Soft Denture Lining Materials Stored in Three Different Mediums

Effect of Water Sorption and Solubility on Two Soft Denture Lining Materials Stored in Three Different Mediums

Comparative Analysis of Properties in Chairside Silicone Denture Liners versus Heat-Cured Molloplast-B: An In-Depth In Vitro Evaluation.

BACKGROUND We investigated the bond strength, tensile strength, and water absorption properties of 4 widely used chairside silicone long-term denture soft lining materials and compared properties with those of heat-cured silicone material. MATERIAL AND METHODS Four chairside materials (GC Reline Soft, Mucopren Soft, Sofreliner Soft, and Elite Soft Relining) and a heat-cured silicone material (Molloplast B) were investigated. For tensile and shear bond strength and tensile strength, samples were prepared according to the manufacturers' instructions and the testing machine used. For water absorption, IOS 1567 was followed to prepare specimens. Bond strengths were measured using a Lloyd Instruments materials testing machine. Ten specimens for each test were prepared for each soft liner, except for water absorption and solubility tests, for which only 5 specimens were prepared. ANOVA, Bonferroni, and Kruskal-Wallis tests were used to compare values of materials and assess changes over time. RESULTS There was strong evidence of differences in the properties between materials. GC Reline Soft showed comparable tensile bond (1.4±0.6 MPa), shear bond (1.1±0.4 MPa), tensile strength (5.44±0.98), water absorption (0.92±0.2 µg/mm³), and solubility values (0.3±0.2 µg/mm3) to that of Molloplast B (1.4±0.4; 1.6±0.5; 4.53±0.9 MPa, 1.7±0.3, and 1.0±0.3 µg/mm³, respectively). The water solubility of Sofreliner Soft was significantly lower (1.5±0.8 µg/mm³) than that of Molloplast B. CONCLUSIONS There were significant differences between some properties of 4 chairside denture soft lining materials and that of Molloplast B, which had higher shear and tensile bond strength than chairside denture silicone soft lining materials but had the highest water solubility.

In vitro comparative assessment of the denture cleansers effectiveness on the surface hardness of permanent silicone denture line

The purpose of the current research was to evaluate the impact of various denture cleaners on the surface hardness of permanent silicone denture lines. In the present study, 124 specimens were included comprising of soft liners made of permanent silicone, which were made from the 15 mm x 10 mm custom metal mold dimensions, where 62 samples were made of Molossil™ and 62 other of Voco™ which are commercially available liners for permanent dentures. These samples were then divided into 4 groups of equal specimen numbers (n=32) depending on the cleansing treatments. Group I specimens were cleaned with water daily, and Group II Polident™ Group III was given SecureTM denture cleaning solution, while Group IV was given PeriogardTM denture cleaning solution. The samples were assessed at 1st week, 1st month, and 6th month after cleanser use. The study results showed that at the 6th-month follow-up after the use of denture cleansers, all of the samples had considerably increased surface hardness compared to the baseline. Statistically significant results were seen with Periogard™, Secure™, and Polident™ compared to Group I controls. In Voco™ denture liners, minor changes were seen compared to Molossil™ soft liners with time in all the groups. The results of this investigation are significantly well cleansing action is seen with Voco™ soft denture lining material compared to Mollosil™ soft denture lining material, and surface hardness is least affected by Polident™ denture cleanser compared to Secure™ and Periogard™ denture cleansing agents.

Effect of Ionic Liquids on Mechanical, Physical, and Antifungal Properties and Biocompatibility of a Soft Denture Lining Material.

This study aims to evaluate the effect of ionic liquids and their structure on the mechanical (tensile bond strength (TBS) and Shore A hardness), mass change, and antifungal properties of soft denture lining material. Butyl pyridinium chloride (BPCL) and octyl pyridinium chloride (OPCL) were synthesized, characterized, and mixed in concentrations ranging from 0.65-10% w/w with a soft denture liner (Molloplast-B) and were divided into seven groups (C, BPCL1-3, and OPCL1-3). The TBS of bar-shaped specimens was calculated on a Universal Testing Machine. For Shore A hardness, disc-shaped specimens were analyzed using a durometer. The mass change (%) of specimens was calculated by the weight loss method. The antifungal potential of ionic liquids and test specimens was measured using agar well and disc diffusion methods (p ≤ 0.05). The alamarBlue assay was performed to assess the biocompatibility of the samples. The mean TBS values of Molloplast-B samples were significantly lower (p ≤ 0.05) for all groups except for OPCL1. Compared with the control, the mean shore A hardness values were significantly higher (p ≤ 0.05) for samples in groups BPCL 2 and 3. After 6 weeks, the OPCL samples showed a significantly lower (p ≤ 0.05) mass change as compared to the control. Agar well diffusion methods demonstrated a maximum zone of inhibition for 2.5% OPCL (20.5 ± 0.05 mm) after 24 h. Disc diffusion methods showed no zones of inhibition. The biocompatibility of the ionic liquid-modified sample was comparable to that of the control. The addition of ionic liquids in Molloplast-B improved the liner's surface texture, increased its hardness, and decreased its % mass change and tensile strength. Ionic liquids exhibited potent antifungal activity.

Assessing the Antifungal Activity of a Soft Denture Liner Loaded with Titanium Oxide Nanoparticles (TiO2 NPs)

Soft denture lining materials are susceptible to be colonized by different microorganisms, especially by Candida albicans (C. albicans), causing denture-induced stomatitis. This study was designed to evaluate the effectiveness of incorporating titanium dioxide nanoparticles (TiO2 NPs) into a soft denture liner towards reducing microbial activity. A total of 40 PEMA-TiO2 nanocomposites samples were fabricated by adding 0.0 wt.% (control), 1.0 wt.%, 1.5 wt.%, and 2 wt.% TiO2 NPs to a heat cured soft denture lining material (polyethyl methacrylate, PEMA). The prepared samples were divided into four groups (n = 10) according to the content of TiO2 NPs. The uniformity of TiO2 NPS distribution within the denture liner matrix was assessed using a Scanning Electron Microscope (SEM). The viable count of C. albicans was evaluated to test the antifungal resistance of the developed composite. The SEM images showed fairly homogeneous dispersion, with patches of TiO2 NPs agglomeration within the PEMA matrix and an increasing concentration of NPs with higher NP content. The particle map and EDX analysis confirmed the evidence of the TiO2 NPs. The mean viable count results for the control (0.0 wt.%) and 1.0 wt.%, 1.5 wt.%, and 2 wt.% TiO2 groups were 139.80, 12.00, 6.20, and 1.00, respectively, with a significant difference from the control group (p < 0.05). The antifungal activity also increased with the increase in the concentration of TiO2 NPs. The addition of TiO2 NPs into a heat-cured soft denture liner provided antifungal activity as evidenced by the reduced colonization of C. albicans. The antimicrobial activity of the liner material increased with the increased concentration of TiO2 NPS.

Effect of non-thermal oxygen-DBD plasma treatment on reducing the phthalate leach and in improving the mechanical strength properties of polymethyl methacrylate denture base and denture liner

Phthalates and esters of aromatic carboxylic acids are used as plasticizers in certain denture soft-lining materials and tissue conditioners. The presence of phthalates is of concern, because they may induce undesirable biological effects such as hormonal disorders, reproductive toxicity, hepatocellular tumours, genital disorders owing to a capacity to bind oestrogen receptors. Despite the potential risk posed by phthalates, their use in denture and denture liner is unavoidable due to the lack of efficient substituent material. Varied curing cycles, solvent wash, thermal plasma treatment/curing, etc., are some of the methods used to eliminate the phthalate content. The use of varied curing cycles, thermal plasma curing etc., will harm the polymer matrix of the acrylic denture resulting in further complication of the acrylic-liner interface bond architecture such as increased wettability, formation of pores, formation of gas pockets, micro fractures at the edges, etc. Hence, in order to overcome the above mentioned, curing of the materials under non thermal Oxygen dielectric barrier discharge (NT-O2/DBD) plasma is suggested. Sets of research samples prepared and lined with PDMS liners (as per ISO 178) were treated with NT-O2/DBD plasma. The treated samples were subjected to mechanical strength tests and calorimetric phthalate leach test. The results indicated that NT-O2/DBD plasma reduced the phthalate content remarkably and improved the overall mechanical strength properties when compared to the controls (thermal plasma treated and heat cured samples).

Analyzing SHORE A hardness to assess the durability of soft denture lining materials

Analyzing SHORE A hardness to assess the durability of soft denture lining materials

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.&#x0D; 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.&#x0D; Results: The outcomes showed non-significant differences (p&gt;0.05) of all studied groups in tear strength and a highly significant (p&lt;0.001) decrease in hardness of all studied groups in comparison with the control group.&#x0D; 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.

Effects of Litsea cubeba Essential Oil Incorporated into Denture Soft Lining Materials.

The antimicrobial properties, cell cytotoxicity and surface hardness of soft lining materials (GC soft liner, Viscogel and Coe comfort) incorporated with various concentrations of Litsea cubeba essential oil (LCEO) were evaluated. The minimum inhibitory concentrations of LCEO against Candida albicans and Streptococcus mutans were 1.25% v/v and 10% v/v, respectively. However, when LCEO was incorporated into the three soft lining materials (GC soft liner, Viscogel and Coe comfort), 10% v/v and 30% v/v of LCEO could inhibit the growth of C. albicans and S. mutans, respectively. The extracts of soft lining materials with 10% and 30% v/v LCEO, 2% chlorhexidine, 30% v/v nystatin and no additive were used for cytotoxicity tests on a human gingival fibroblast cell line. There was no significant difference in cell viability in all groups with additives compared to the no additive group (p > 0.05). Surface hardness increased significantly between 2 h and 7 day incubation times in all groups, including the controls (p < 0.05). A higher LCEO concentration had a dose-dependent effect on the surface hardness of all soft lining materials (p < 0.05). However, the surface hardness of materials with additive remained in accordance with ISO 10139-1. LCEO could be used as a natural product against oral pathogens, without having a negative impact on soft lining materials.

Adherence of Candida albicans to Five Long-Term Silicone-Based Denture Lining Materials Bonded to CAD-CAM Denture Base.

Knowledge about quantifying the number as well as the retention and adhesion of Candida albicans blastoconidia to silicone denture liners is limited. Thus, the aim of this in vitro study was to explore the adherence of C. albicans to the surface of five long-term silicone-based soft denture lining materials, using artificial saliva. A total of 50 specimens (10 × 10 × 3 mm) of five long-term resilient liners (Molloplast-B; GC Reline Soft; Elite Soft Relining; Tokuyama Sofreliner S; Ufigel SC), bonded to a computer-aided design and computer-aided manufacturing denture base, were prepared. The specimens were inoculated and incubated in artificial saliva for 1 and 24 hours with a standardized (2.8 × 106 cfu/ml) C. albicans suspension. At the end of the incubation period, the specimens were stained with acridine orange and observed using fluorescence microscopy. After 1 hour and in 24 hours, Molloplast B demonstrated significantly earlier adherence of C. albicans cells compared to the other chairside materials (p < 0.001 and p < 0.001, respectively), where the mean number of cells also increased in the frontal parts. Regarding the rate of C. albicans proliferation from 1 to 24 hours within the materials, there was an increase in all materials (Molloplast B: p < 0.001; GC Reline Soft: p = 0.220; Elite Soft Relining: p = 0.032; Tokuyama Sofreliner S: p = 0.001; Ufigel Sc: p = 0.001). The Ufigel Sc showed a significant 2.5-fold increase at 24 hours. Long-term silicone denture liners accumulate a significant amount of C. albicans blastoconidia and their coverage by them increases progressively over time.

Investigating Tensile Bonding and Other Properties of Yttrium Oxide Nanoparticles Impregnated Heat-Cured Soft-Denture Lining Composite In Vitro.

ABSTRACTAims:This study was conducted to assess the effect of the addition of yttrium oxide (Y2O3) nanoparticles on the tensile bond strength, tear strength, shore A hardness, and surface roughness of soft-denture lining material.Materials and Methods:Y2O3 NPs with 1.5 and 2 wt.% were added into acrylic-based heat-cured soft-denture liner. A total of 120 specimens were prepared and divided into four groups according to the test to be performed (tensile bond strength, tear strength, surface hardness, and surface roughness).Results:There was a highly significant increase in tensile bond strength between the soft liner and the acrylic denture base, tear strength, and hardness at both concentrations as compared to the control group, whereas there was a nonsignificant difference between 1.5wt% of Y2O3 nanoparticles and the control group, and between 1.5wt% and 2wt% of Y2O3 nanoparticles. But there was a significant difference between 2wt% of Y2O3 nanoparticles and the control group.Conclusion:The Y2O3 nanoparticles impregnated in soft-lining materials increased the mechanical properties of both tensile bonding strength and tear strength. Also, there was a significant increase in hardness but there was no change in surface roughness of acrylic-based denture soft-lining materials.

Influence of Thermocycling and Sealer Coating Application on Shore Hardness of Soft Denture Lining Material

BACKGROUND: One of the properties of the soft denture lining (SDL) material that needed to overcome the functional problems is softness. Loss of softness due to the aging process and to extend the duration of use, sealer coating was developed to maintain its softness. Sealer coating acts as mechanical barrier to provide protection against aging of SDL materials. AIM: This study aims to determine the influence of thermocycling and sealer coating application on the shore hardness of the acrylic-based and silicone-based auto-polymerizing soft denture lining materials. MATERIALS AND METHODS: Materials that were used in this study are acrylic-based auto-polymerizing SDL (Durabase Soft, Reliance Dental Manufacturing LLC, Illinois, USA) and silicone-based auto-polymerizing SDL (Mollosil, Detax GmbH, Ettlingen, Germany). In this study, we used monopoly as sealer coating for acrylic-based auto-polymerizing SDL and varnish for silicone-based auto-polymerizing SDL. Thermocycling was performed for 2000 cycles for a 2-year simulation time. For shore hardness test, a total of 40 discs shaped samples were made with a diameter of 35 mm and a thickness of 6 mm. The samples were divided into eight groups (n = 5), namely, the uncoated and non-thermocycling acrylic-based auto-polymerizing SDL, the coated and non-thermocycling acrylic-based auto-polymerizing SDL, the uncoated and thermocycling acrylic-based auto-polymerizing SDL, the coated and thermocycling acrylic-based auto-polymerizing SDL, the uncoated and non-thermocycling silicone-based auto-polymerizing SDL, the coated and non-thermocycling silicone-based auto-polymerizing SDL, the uncoated and thermocycling silicone-based auto-polymerizing SDL, and the coated and thermocycling silicone-based auto-polymerizing SDL. The hardness test was carried out using the shore A durometer. RESULTS: The obtained data were tested using the independent t-test with a significance level of p &lt; 0.05. The results showed that there was a significant effect between coated and uncoated acrylic-based SDL group that underwent thermocycling and in the silicone-based SDL group. The study showed that the hardness value was lower in both coated acrylic-based and silicone-based SDL groups compared to the non-coated group, so it can be concluded that the sealer coating is able to protect the hardness of SDL material against aging with a thermocycling simulation. The results also showed that there was a significant effect of thermocycling on the hardness of the material both in the coated acrylic-based SDL group, the uncoated acrylic-based SDL group, and the uncoated silicone-based SDL group. Study also showed that there was no significant effect of thermocycling in the coated silicone-based SDL group. CONCLUSION: Based on the results, it can be concluded that the use of sealer coating can maintain the hardness properties of both acrylic-based SDL and silicon-based self-polymerizing SDL so that it can increase the durability of SDL materials. However, the effect of sealer coating in protecting the hardness of SDL materials against aging was more evident in the silicone-based SDL group.

Comparative evaluation of the effectiveness of denture cleansers on surface hardness of permanent silicone denture liners – An In vitro study

Aim:This study aimed to determine the effect of three commercially available denture cleansers on surface hardness of two different silicone denture liners at various time intervals.Materials and Methods:A total of 120 cylindrical specimens of permanent silicone-based soft liners were prepared from a custom made metal mold with dimensions of 15 mm × 10 mm, of which 60 specimens were fabricated using Voco™ and the remaining 60 specimens with Molossil™ permanent denture liners. All specimens were divided into four major groups based on cleansing treatments, comprising 30 specimens each. And then, all cleansers dissolved in 250 mL water as recommended by the manufacturer. Specimens of the first group were cleansed daily by rinsing with water and second group with Periogard™ denture cleansing solution and third group with Secure™ denture cleansing solution and the fourth group with Polident™ denture cleansing solution. Specimens of all groups were tested on 1st week, 1st month, and 6th month time interval using a Shore A Durometer. Three readings were noted for each sample and the mean of those readings was taken.Results:Surface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Statistically significant changes were observed between Polident™, Secure™, and Periogard™ denture cleanser groups over control with time. Minor changes were observed in surface hardness of Voco™ denture liners as compared to Molossil™ soft liners for all groups, as time progressed.Conclusion:Voco™ soft denture lining material can be performed significantly better than Mollosil™ soft denture lining material in all cleansing treatments and Polident™ denture cleanser has the least effect on surface hardness of soft liners than Periogard™ and Secure™ denture cleansing agents.

Photodynamic antimicrobial chemotherapy through photosensitizers loaded poly-l-glycolic acid on Candida albicans in denture lining material: Release, biological and hardness study.

The aim of this in-vitro study was to formulate poly-l-glycolic acid nanoparticles loaded with methylene blue (PLGA-MB) and to characterize their physicochemical features, photosensitizer-release kinetics and antimicrobial efficacy against Candida albicans (C. albicans) after incorporating in polymethyl methacrylate (PMMA) denture lining materials. MB-PLGA nanoparticles were synthesized according to the modified nanoprecipitation method. The morphological characterization of the nanoparticles was studied under scanning and transmission electron microscope. Particle size, surface charge, polydispersity index (PDI) and MB release were evaluated. The effect of 660 nm semiconductor AlGaInP diode laser on C. albicans was studied in vitro. The PMMA was weighed and PLGA free and PLGA-MB were added in the lining material according to the weight percentage as 2.0 wt.% and 5.0 wt.% and tested for the diameter of the inhibition zones of C. albicans growth and shore A hardness. Homogenous spherical nanoparticles with round morphology with size ranging between 60-80 nm were observed while PLGA-MB were seen to have irregular structure within the nanoparticle under TEM. PLGA-Free was larger in size than the loaded PLGA (∼62 nm) that evidenced reduction in size by adding the MB photosensitizer. PDI recordings reduced from 0.198 for the PLGA-Free nanoparticles to 0.164 for the PLGA-MB nanoparticles. The entrapment efficiency of MB inside PLGA showed an average percentage of ∼75 % uptake that resulted in the overall loading of ∼15 %. An overall inhibition of 78 %, 41 % and 28 % of C. albicans growth was seen with a concentration of 0.1, 0.5 and 1.0 μg/mL, respectively. The application of PLGA nanoparticles loaded with MB evidenced >75 % of C. albicans. MB incorporation did not lead to a clinically relevant change on shore A hardness. PLGA loaded with MB is believed to have promising target therapy against C. albicans in denture soft lining materials in terms of PACT in vitro. The synergistic association between PLGA and MB proved enhanced antifungal activity. PLGA-MB could be an important tool in nanobiotechnology and photodynamic therapy for novel formulations with higher antimicrobial efficacy and improved drug delivery from denture soft lining materials.

The Effect of Incorporation Kappa-Carrageenan Powder on the Physical and Mechanical Properties of the Heat-Cured Acrylic-based Soft Denture Lining Material in Clinical Use

Background: Soft denture relining materials have been introduced to prosthetic dentistry since long timeto improve the patient’s acceptance to dental prosthesis. However, with the growing need to provide thepatients with dentures that have improved comfort and masticatory efficiency, there is a growing demand toimprove several features of the denture lining materials. Therefore, the aims of this study was to evaluatethe effect of incorporation kappa-carrageenan powder as antifungal agent on the hardness and peel bondstrength of the heat-cured acrylic-based soft denture lining material.Materials and Methods: Two percentages of kappa-carrageenan powder (1.5wt.% and 2wt.%) have beenselected based on the pilot study that produced the best antifungal effect. A total of sixty samples wereprepared and divided into three equal groups groupA:0.0wt.%, groupB:1.5wt.%, groupC:2wt.% of kappacarrageenan powder additive. Each group was further subdivided into two equal groups for shore-A hardnesstest and peel bond strength test. Fourier transform infrared spectroscopy (FTIR) analysis was performed toinvestigate if there is any chemical reaction between the soft lining material and the kappa-carrageenanpowder, scanning electron microscope (SEM) was used to determine the distribution of kappa-carrageenanpowder in the soft liner matrix.Results: All the resulted data were analysed using “one-way analysis of variance (ANOVA) and DunnetT3 post-hoc test at a significance level of p&lt;0.05”. The result of shore-A hardness test revealed significantincrease (P&lt;0.05) in the values of hardness of both experimental groups (B and C) when compared with thecontrol group(A). Peel bond strength test revealed non-significant decrease (P&gt;0.05) in the values of peelbond strength for experimental group(B), while there was significant decrease (P&lt;0.05) for the experimentalgroup(C) when compared to the control group. FTIR analysis showed no difference in the spectra betweencontrol group and experimental group this means that there is no chemical interaction between the twomaterials. SEM test results showed a degree of agglomeration of the kappa-carrageenan powder into the softliner matrix.Conclusion: Adding kappa-carrageenan powder to the soft liner affected the physical and mechanicalproperties of the lining material and the most adverse effect was noted for the group C(2 wt.%) but all effectswas in the acceptable range for clinical use.