Soft Lines Research Articles

One-year clinical investigation of the effect of inclusion of three nanoparticles in the heat-cured acrylic resin denture base on the adhesion with the silicone soft-liner

Abstract Purpose: To evaluate the effect of incorporating three nanoparticles (Titanium oxide, silicon oxide, and alumina) with 1% and 5% concentration on the bond strength to denture base for one year of clinical service. Methods: Fifty-six completely edentulous patients were selected and divided into seven groups according to the nanoparticle material and concentration (n=7). Upper and lower complete dentures were fabricated for each patient. The adhesion of soft liner was done using a five scale questionnaire at insertion (baseline) 4, 8, and 12 months of denture insertion. The data were analyzed by Friedman test with post-hoc Dunn test. Results: At 4 and 8 months, all the nanoparticles groups showed a non-statistically significant difference from the baseline. At 12 months, all groups with 5% nanoparticle concentration showed a statistically significant decrease in the soft liner adhesion. The same insignificance was found between the control and the baseline. And in-between all of the groups of the nanoparticles during all of the follow-up intervals. Conclusion: The addition of nanoparticles to the denture base effectively improved the bond between the soft-liner and the denture base, especially for concentrations below 5%.

Influence of Silver-Zinc Zeolite Incorporation on Shear Bond Strength of Silicon Cold Cure Soft Liner

Back ground: Reduction of a durable bond to acrylic denture base is the main problem associated with soft liner materials.
 Purpose: Evaluation of the influence of addition of Ag-Zn Zeolite on shear bond strength of silicon cold cure soft liner.
 Approach: thirty specimens of silicon cold cure soft liner were constructed for shear bond- strength test and divided into three groups: Control groups: 10 specimens without incorporation of Ag-Zn Zeolite, Experimental group: 10 specimens with 0.5% by weight of Ag-Zn Zeolite Experimental Group: 10 specimens with 0.75 %by weight of Ag-Zn Zeolite Plastic pattern of acrylic block with dimensions (75 mm length x 25mm width x 5mm depth )was fabricated and evaluated by Instron testing machine.
 Results: Least significant difference of (0.75%) of Ag-Zn zeolite group was significantly different compared with the experimental group of (0.5% and control group) at p<0.05.
 Conclusion: The incorporation of 0.5%, 0.75% by weight into silicon cold cure soft liner had significant effect and causes improvement in shear bond strength.

Retention force dynamics of two different soft liners over ball abutments for mandibular implant overdentures

Retention force dynamics of two different soft liners over ball abutments for mandibular implant overdentures

Design of a Single Layer Metamaterial for Pressure Offloading of Transtibial Amputees.

While using a prosthesis, transtibial amputees can experience pain and discomfort brought on by large pressure gradients at the interface between the residual limb and the prosthetic socket. Current prosthetic interface solutions attempt to alleviate these pressure gradients using soft homogenous liners to reduce and distribute pressures. This research investigates an additively manufactured metamaterial inlay with a tailored mechanical response to reduce peak pressure gradients around the limb. The inlay uses a hyperelastic behaving metamaterial (US10244818) comprised of triangular pattern unit cells, 3D printed with walls of various thicknesses controlled by draft angles. The hyperelastic material properties are modeled using a Yeoh third-order model. The third-order coefficients can be adjusted and optimized, which corresponds to a change in the unit cell wall thickness to create an inlay that can meet the unique offloading needs of an amputee. Finite element analysis simulations evaluated the pressure gradient reduction from (1) a standard homogenous silicone liner, (2) a prosthetist's inlay prescription that utilizes three variations of the metamaterial, and (3) a metamaterial solution with optimized Yeoh third-order coefficients. Compared to a traditional homogenous silicone liner for two unique limb loading scenarios, the prosthetist prescribed inlay and the optimized material inlay can achieve equal or greater pressure gradient reduction capabilities. These preliminary results show the potential feasibility of implementing this metamaterial as a method of personalized medicine for transtibial amputees by creating a customizable interface solution to meet the unique performance needs of an individual patient.

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<0.05). Conclusion: There was effect of different denture cleansers on hardness of acrylic soft liner. Keywords: soft liner, denture cleanser, cinnamon

Computer model and complete set of a functional non-alcoholic beverage production line

Production of functional products using local raw materials with a high content of biologically active substances is the main trend in the production of non-alcoholic beverages. In this regard, creation of a technological line that ensures not only the quality of the finished product, but also the safety of the functional properties of the feedstock is of great interest. A computer model of a functional soft drink production line, developed using the MasterSCADA 4D software created by a leading domestic company has been. The model emulates the entire production process including the stage of filling the finished product. It is possible to control a real production line provided that communication with an industrial controller, sensors and actuators is installed and configured. A set of technological equipment has been selected for each production stage, from processing raw materials and on down to functional soft drink packaging. Recommendations have been given for water treatment, including a number of technological processes, such as rough water purification and disinfection. There are instructions for preparing sugar syrup using hot method. The characteristics of the recommended plant for hydrodynamic extraction from plant raw materials has been presented. A factor intensifying the extraction process, in the pulsating action of the extractant between the solid and liquid phases. Production of a functional drink implies using of water as an extractant, so additional methods of intensifying mass transfer processes have been considered in order to increase the percentage of extraction of target components. The use of the effect of ultrasonic, electric, pulse and discrete-pulse fields on raw materials is considered to be the most promising method for the extraction process intensification.

Erratum to: Incorporation of Fluconazole and Ocimum Sanctum Oil in Soft Denture Liners to Treat Biofilms of Candida albicans Associated with Denture Stomatitis

Purpose: To investigate the In Vitro activity of incorporated antifungal agents like Fluconazole and Ocimum sanctum oil (Tulsi) in the denture soft liners to reduce the risks associated with the biofilms of Candida albicans.Materials and Methods: In the current study, the minimum inhibitory concentration (MIC) of two antifungal agents namely Fluconazole and O. sanctum (Tulsi oil) against C. albicans (ATCC 10231) was evaluated to examine their effect in reducing the count of candida and its biofilms. Analysis of physical properties such as surface roughness and hardness of soft denture liners (test and control) were also performed. The effect of both antifungal agents was also observed on cell morphology of candida cells using scanning electron microscopy (SEM).Results: Studies confirmed MIC value for fluconazole and O. sanctum oil as 600 and 400 µg/ml respectively. Surface hardness and roughness of soft denture material (test) remained unaltered. Finally, SEM studies also proved the effectiveness of incorporated antifungal agents on the cell morphology of C. albicans at their respective MIC values.Conclusions: This approach allows the prolonged drug release in the oral cavity which simultaneously treats the injured denture bearing tissues and also the infection, biofilms of candida without compromising on their physical properties. These studies are significant and have tremendous medicinal and therapeutic relevance. Keywords: Antifungal Agents; Biofilms; Candida; Scanning Electron Microscope; Soft Liners; Hardness; Surface Roughness; Minimal Inhibitory Concentration; Denture Stomatitis.

Stress distribution analysis of oral mucosa under soft denture liners using smoothed particle hydrodynamics method

This study aims to simulate the stress distributions of oral mucosa under different soft denture liners using the smoothed particle hydrodynamics (SPH) method. The Young's modulus and viscosity of denture liners composed of silicone (Sofreliner Super Soft and Sofreliner Tough Medium, Tokuyama Dental), acrylic (Vertex Soft, Vertex Dental), and a tissue conditioner (Visco-gel, Dentsply Sirona) were measured using a creep meter. A numerical simulation model that represents the stress distribution of oral mucosa under soft denture liners was also developed using the SPH method. The oral mucosa was divided into four regions: A) buccal border, B) buccal shelf, C) crest of residual ridge, and D) lingual border. For each region, the von Mises stress (hereafter, referred to as “Mises stress”) of the oral mucosa was calculated. Based on a creep test, Sofreliner Super Soft and Sofreliner Tough Medium silicone liners showed an elastic behavior, whereas Vertex Soft acrylic liner and Visco-gel tissue conditioner showed a viscoelastic behavior. In addition, Sofreliner Super Soft and Visco-gel exhibited a large strain. The numerical simulation revealed that the mean Mises stress was the highest in region A and lowest in region D. Vertex Soft acrylic liners resulted in a statistically lower Mises stress on the oral mucosa compared to the other three soft denture liners. Different soft denture liner materials lead to different stress distributions on the oral mucosa. The acrylic soft denture liners cause a lower Mises stress on the oral mucosa than the silicon soft denture liners. This suggests that acrylic soft denture liners would be more effective for manufacturing painless dentures than silicone soft denture liners.

Flexural strength and flexural modulus of fiber-reinforced, soft-liner retained implant overdenture.

To compare the flexural strength and modulus of ball-soft liner–retained overdentures vs ballsocket– retained overdentures, as well as to evaluate the effect of using glass fiber reinforcement on the mechanical properties of ball-soft liner–retained overdentures. A total of 80 overdenture specimens were fabricated and divided equally into four groups (n = 20/group): specimens with a metal matrix (group 1); a silicone soft liner matrix (group 2); reinforced with one bundle of unidirectional Stick glass fiber placed above the silicone soft liner matrix (group 3); and reinforced with four weaves of bidirectional Stick Net glass fibers placed above the silicone soft liner matrix (group 4). Half of the specimens from each group were stored in water at room temperature (23°C ± 1°C) for 24 hours, while the other half were stored in water at 37°C for 30 days before being subjected to a static three-point loading test. After 1 day of water storage, the flexural strength and flexural modulus values of groups 1, 3, and 4 were not significantly different from each other (P = .788, P = .084), but were significantly higher than group 2 (P < .05). Water storage for 30 days significantly decreased the flexural strength of group 1 only (P < .001) and not the other three groups (P >.05). Overdentures retained with a metal matrix were not significantly different from those retained with a silicone soft liner matrix in terms of flexural strength and modulus after 30 days of water storage. Placing unidirectional and bidirectional glass-fiber reinforcement above soft liner matrices can increase the flexural strength of ball-soft liner–retained overdentures.

Incorporation of Fluconazole and Ocimum Sanctum Oil in Soft Denture Liners to Treat Biofilms of Candida albicans Associated with Denture Stomatitis

Purpose: To investigate the In Vitro activity of incorporated antifungal agents like Fluconazole and Ocimum sanctum oil (Tulsi) in the denture soft liners to reduce the risks associated with the biofilms of Candida albicans.Materials and Methods: In the current study, the minimum inhibitory concentration (MIC) of two antifungal agents namely Fluconazole and O. sanctum (Tulsi oil) against C. albicans (ATCC 10231) was evaluated to examine their effect in reducing the count of candida and its biofilms. Analysis of physical properties such as surface roughness and hardness of soft denture liners (test and control) were also performed. The effect of both antifungal agents was also observed on cell morphology of candida cells using scanning electron microscopy (SEM).Results: Studies confirmed MIC value for fluconazole and O. sanctum oil as 600 and 400 µg/ml respectively. Surface hardness and roughness of soft denture material (test) remained unaltered. Finally, SEM studies also proved the effectiveness of incorporated antifungal agents on the cell morphology of C. albicans at their respective MIC values.Conclusions: This approach allows the prolonged drug release in the oral cavity which simultaneously treats the injured denture bearing tissues and also the infection, biofilms of candida without compromising on their physical properties. These studies are significant and have tremendous medicinal and therapeutic relevance.

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.

Investigation of dental elastomers as oral mucosa simulant materials.

ObjectiveTo measure mechanical properties of dental soft liners in tensional stress to identify their suitability as human oral mucosa simulant materials.MethodsEleven different dental elastomers were subjected to tensile testing to obtain their tensile strength and elastic moduli (n = 15/group) according to the ISO‐527 method. Fractured surfaces of one specimen per sample group were examined under the light microscope and scanning electron microscope (SEM). Energy‐dispersive X‐ray spectroscopy (EDS) was performed for the elemental analysis or chemical characterization of each sample group. The obtained data were quantitatively and qualitatively analysed. They were also statistically analysed using SPSS version 25.ResultsThe tensile strength of dental elastomers ranged from 0.43 MPa (±0.09) to 7.41 MPa (±1.11) and had statistically significant differences between tested groups (p = 0.001). Vertex soft heat‐cure soft liner, GC impression silicones and Silagum soft liners were found to have tensile strengths close to that of the oral mucosa reported by previous studies. SEM analysis revealed that the elastomers with higher filler contents showed rough fractured surface with plucking of particles after tensile fracture.ConclusionThis is the first study assessing the suitability of dental elastomers as human oral mucosa simulant materials which can be used for in vitro, mathematical modeling and finite element analysis (FEA) to study masticatory force distribution in oral mucosa. Out of 11 studied, six (Vertex Soft, GC heavy and Light body, Molloplast B, Algin X Ultra and Exaclear) dental elastomers showed similar mechanical properties to the Theil embalmed gingival tissues. Vertex Soft, GC Light body, and Molloplast B may be used for the majority of oral mucosal model when considering tensile strength as the primary factor for mechanical stimulation.

An in vitro evaluation of tensile bond strength of soft liners bonded to different denture base resins.

Background:Clinically, adhesion failure is the most critical problem because of the failure of the optimal bond between denture base and the soft liner.Objectives:This study was performed to assess the tensile bond strength of two temporary soft liners to different denture base resins.Materials and Methods:Forty-eight blocks with 16 samples each of heat-cured denture base resin of three different types were fabricated from custom-made stainless steel die after de-waxing mold space. Surface roughening of each acrylic resin specimens which bonds with soft liners was done by abrading the surface and to this temporary soft liners (Perma soft denture liner and Pro soft denture liner) were bonded. The universal testing machine was used to test the tensile strength of bonded space. The results were statistically analyzed using the Statistical Software IBM SPSS Statistics for Windows, version 20.0. (Armonk, NY, USA: IBM Corp.) using the Chi-square test, Post hoc Tukey's HSD, and two way ANOVA tests.Results:It was observed that Perma soft was prevalent over Pro-soft denture liner on the basis of tensile bond strength with all three different types of denture base resins. Trevalon HI and acrylic composite exhibited better bond strength results with both Perma soft and GC Pro-soft denture liner as compared to other types of denture base resins.Conclusion:Perma soft had a better bond strength compared to Pro-soft denture liner in bonding modified denture base and conventional resins.

Effect of soft liner on clinical implication of tooth supported overdenture

Background/aim Overdentures are considered as the most preferred treatment modality in patients with few remaining teeth, especially after using different denture liners. The present study aims to compare between the clinical performance of tooth supported overdentures relined with three different types (hard denture liner, silicon soft liner, and acrylic resin based soft liner) regarding modified bleeding index, probing depth, and patient satisfaction. Patients and methods A total of 21 partially edentulous patients with one remaining tooth on each side received overdentures constructed with conventional method after abutment preparation. Then dentures were classified randomly into three groups according to relining material: group I was relined with hard liner, group II was relined with silicon soft liner, and group III was relined with acrylic resin soft liner. All patients were recalled after 1, 3, and 6 months. At recall visits, assessment of the oral health status was performed by measuring probing depth and modified bleeding index by using periodontal probe. Moreover, patient satisfaction was evaluated using Oral Health Impacts Profile-14 questionnaire. Results One-way analysis of variance (ANOVA) was performed to compare among the three groups, which revealed significant difference between them in all follow-up periods regarding modified bleeding index, probing depth, and patient satisfaction, followed by Tukey’s post-hoc test for multiple comparisons, which revealed a significant difference among all groups (P&lt;0.05). On the contrary, comparison was performed between different follow-up periods in each group by repetitive one-way ANOVA test, which revealed a significant difference in all groups regarding modified bleeding index and probing depth, whereas revealed insignificant difference in patient satisfaction. Repetitive one-way ANOVA test was followed by Tukey’s post-hoc test for multiple comparisons, which revealed significant difference between T1 and T2 and between T1 and T3 in all groups regarding modified bleeding index, whereas revealed a significant difference between T1 and T3 in all groups regarding probing depth, but in patient satisfaction, insignificant difference was revealed. Conclusion Acrylic resin soft liner showed the best clinical performance then silicon soft liner followed by hard liner regarding modified bleeding index, probing depth, and patient satisfaction during the follow-up period.

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.

Comparative Study of Silicone-based Soft Liner Versus Versacryl Liner for Mandibular Complete Denture Cases (Randomized Clinical Trial)

A randomized clinical trial was carried out to compare between conventional silicone-based soft liner and Versacryl lining material for the relining of mandibular complete dentures in flat mandibular cases regarding oral health related quality of life and tissue keratinization index. Twenty-eight patients were distributed randomly into two groups (fourteen per group). After taking the relining impression for their existing mandibular dentures, the control group received conventional silicone based soft liner, while the intervention group received Versacryl lining material. Patients were evaluated at two weeks, two months and four months intervals. The results showed a significant difference between the two groups at two weeks and two months as the Versacryl relined dentures provided a better improvement in oral health related quality of life, while at four months there was no difference between the two groups. This study also showed a significant difference in parakeratization activity between the two groups at all follow up periods with the highest mean score in the Molloplast-B liner group.

Research and restocking of wheat varieties to pathogens of especially dangerous fungal diseases

Based on the results of immunological assessments and rejection of the material by phenotype, 327 sources and 79 donors of immunity were selected from spring wheat, 27 and 23 from winter wheat, respectively. Applying PCR diagnostic method, Lr genes were found in the selected samples of spring wheat. Screening revealed the presence of the following genes in the studied samples. They are Lr9, Lr19, Lr24, Lr 34, Lr1, Lr10, Lr20 and Lr26. Within selection samples of the Central Russian branch, the prevalence of lines with the Lr19 gene in combination with inefficient genes Lr10, Lr20 and Lr26 was revealed. Spring soft wheat cultivation lines adapted to zonal conditions have been developed, combining in their phenotype resistance to the main phytopathogens of the region with valuable economic properties. In 2019, a variety of spring soft wheat in memory of Plahotnik was transferred to the State Export Commission for testing.

Comparative Evaluation of the Tensile Bond Strength of Heat-Cured Soft Liners with Nanoparticles Reinforced Polymethylmethacrylate (PMMA) Resins in Polymerized and Unpolymerized Forms: An in Vitro Study

Comparative Evaluation of the Tensile Bond Strength of Heat-Cured Soft Liners with Nanoparticles Reinforced Polymethylmethacrylate (PMMA) Resins in Polymerized and Unpolymerized Forms: An in Vitro Study

Peel bond strength between a silicone-based soft liner and a heat-cured acrylic resin denture base reinforced with three concentrations of metal oxide nanoparticles

Purpose: To evaluate the effect of incorporation of 0.1%, 0.3%, and 0.5% concentrations of titanium oxide, aluminum oxide, and silica nanoparticles in the heat-cured acrylic resin denture base on the peel bond strength to a silicone denture liner. Methods: A total number of 100 heat-cured acrylic resin samples were prepared and classified into a control group and three groups according to the type of nanoparticle. Each group was classified into three subgroups according to the concentration of the nanoparticle (n=10). A Silicone based-soft liner was added over the acrylic resin specimens, and the peel bond strength was measured using the peeling bond strength test at an angle of 90°. Statistical analysis was done using a Two-way ANOVA test for interactions between peel bond strength and the different nanoparticle materials and their concentrations. Results: Two-way ANOVA showed that the three nanoparticles and different concentrations did not affect the peel bond strength. Conclusion: The nanoparticles in this study were not effective in increasing peel bond strength at the studied concentrations.

Assessment of the Water Sorption and Hardness of Silicone and Acrylic-Based Soft Liners at Different Time Period: An in vitro Study

Assessment of the Water Sorption and Hardness of Silicone and Acrylic-Based Soft Liners at Different Time Period: An in vitro Study