Self-sanitizing soft denture liners: paradoxical results.

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

Background: Denture liners have been used in dentistry for many years. Soft denture liner is one of the denture liners which used to enhance the fit of poor fitting dentures and prevent trauma to sensitive mucosa. One of the disadvantages of the soft denture liner is the frequent debonding from the denture during clinical use thus reducing the longevity of such prosthesis. Glass fibers integrated at or on the fitting surface of the denture used to improve the bonding of the silicone soft liner to the acrylic surface. Materials and methods: the shear bond strength calculated to evaluate the effect of the glass fiber surface treatment on the bonding between the acrylic surface and the silicon soft liner. 120 samples were prepared and divided into 3 major groups: Group I for the conventional heat cure acrylic, Group II for the pour acrylic and Group III for the light cure acrylic. Each one of these major groups divided into 2 subgroups, the first one for the Mollosil silicon soft liner and the second one is for the Molloplast-B silicon soft liner. Each one of these sub groups consist of 2 types of the acrylic surface: smooth (control) and glass fiber net surface treatment. Results: this study revealed that some types of the surface treatment exhibited a highly significant improvement in the bonding between the acrylic surface and the soft liner. Conclusion: glass fiber surface treatment could improve the bonding between the acrylic surface and the soft liner.

To evaluate the surface alterations of soft liners with or without sealer coating following abrasion with mechanical brushing. Thirty specimens were made of a methacrylate- (Coe-Soft) and a siloxane-based material (Ufi-Gel SC), and 15 received two coatings of surface sealer. The specimens were submitted to a mechanical brushing-dentifrice assay under 200g of force at 250 cycles/min. Mechanical brushing was simulated for a period of 1 (1250 cycles) and 6 months (5000 cycles). Surface roughness (Ra parameter) was measured, and scanning electron microscopy (SEM) images were obtained. Ra data were analysed by anova for repeated measures and Bonferroni's test (alpha=0.05). Ra increased from baseline to 6 months regardless of sealer coating. At baseline, only Coe-Soft without sealer had a higher Ra than the other groups. After 1 month, the Ra of Coe-Soft with sealer was three-fold higher than the Ra at baseline; the other groups showed no significant increase of Ra. SEM images showed degradation of the soft liners over time, except for the Ufi-Gel SC with sealer, which displayed minimum alteration of surface texture. Sealer coating reduced the surface degradation of the tested soft liners, but the protective effect was more pronounced for the siloxane-based material.

Microleakage study of various soft denture liners by autoradiography: Effect of accelerated aging

The bond strength of soft denture liner to a recently introduced denture base resin after thermocycling has not been compared to traditional denture base materials. The objective of this study was to investigate the effects of thermocycling on the tensile bond strength of soft denture liners to two chemically different denture base resins, polymethyl methacrylate (PMMA) and urethane dimethacrylate (UDMA). A total of 48 PMMA and UDMA tensile test specimens were fabricated by attaching two different soft denture liners (Molloplast-B, Permaflex) according to the manufacturers' instructions and assigned to two groups. Half of the specimens for each group were stored in water for 1 week, and the other half were thermocycled (5000 cycles) between baths of 5°C and 55°C. Specimens were mounted on a universal testing machine with a 5 mm/min crosshead speed. The data were analyzed with three-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (α = 0.05). The highest bond strength was measured in the specimens from the UDMA/Molloplast groups, and the lowest was seen in the PMMA/Permaflex group. No significant difference in bond strength was detected in PMMA/Permaflex groups after thermocycling (p = 0.082), whereas other groups exhibited significant differences after thermocycling (p < 0.05). Thermocycling decreased the bond strength values in both the PMMA and UDMA groups. Regardless of types of soft liners, PMMA specimens presented lower bond strength values than UDMA specimens, both before and after thermocycling.

Objective: Soft denture liners are essential in prosthodontics due to their ability to cushion masticatory forces and provide comfort to patients with compromised oral tissues. Despite their clinical benefits, conventional soft liners suffer from significant limitations, including poor bond strength with the denture base, surface degradation, microbial colonization, and limited mechanical resilience. The goal was to assess improvements in shear bond strength and other related surface properties such as surface hardness, and a reduction in C. albicans adherence. Material and Methods: Strontium Titanate (SrTiO₃) nanoparticles were obtained from, and a self-cured soft denture liner was sourced from. All procedures were performed under conditions simulating intraoral temperature, following the manufacturer’s instructions. A dry-heat oven was used for sample conditioning. A total of 45 specimens were fabricated and equally allocated into three experimental groups containing 0%, 1%, and 1.5% concentrations of strontium titanate (SrTiO₃), respectively. Results: The results indicated that SrTiO₃ can play a valuable role in the development of advanced soft lining materials with enhanced durability, biocompatibility, and clinical effectiveness. Conclusion: The incorporation of Strontium Titanate (SrTiO₃) nanoparticles at concentrations of 1% and 1.5% significantly improves the mechanical properties, surface roughness, and reduction in antifungal behavior of acrylic-based soft denture liners.

This in-vivo investigation evaluated the effect of 2 denture sealer agents on the microbial colonization of a newly placed soft interim denture liner during a period of 14 days. An interim soft denture liner (Coe-Soft; GC America, Alsip, IL) was coated with 2 different denture surface sealants (Palaseal [Heraeus Kulzer, Irvine, CA] and Mono-Poly [Plastodent, New York, NY]). Three rectangular wells of 1 cm wide x 2 cm long x 2 mm deep were placed in the intaglio of 10 maxillary complete dentures and filled with the soft liner material. The soft liner surface was treated with Palaseal (first well) and Mono-Poly (second well), and the unsealed (third well) was used as a control. These were exposed to the oral cavity for 14 days. The effect the sealant had in the prevention of Candidal colonization in vivo of the soft liner material was evaluated. Microbiological specimens were recovered from all samples and cultivated. Microbiological data from the control and 2-test samples in each denture were tabulated, and statistical analyses were performed. This investigation showed clear differences (p <.001) between the sealed and unsealed soft liners. The sealed material showed significantly less colonization by yeast and bacteria. Intercomparison of the surface denture sealers, Palaseal versus Mono-Poly, showed no statistically significant differences (p < .005) in total yeast or bacterial colonization. Coating of Coe-Soft denture liner with either Palaseal or Mono-Poly significantly decreased yeast and bacterial colonization. .

The purpose of this study was to determine the influence of plasticizer content on the tensile bond strength of heat-cured acrylic soft denture liners to a denture base resin. Differences among materials were significant, except for 100 wt% Dibutyl Sebacate (DBS) and 80 wt% DBS of tensile bond strength. The bond strength of all materials to the denture base increased with an increase in thermal cycles significantly except for 40 wt% DBS. The tensile bond strength of soft denture liners to the denture base resin significantly decreased with an increase of plasticizer contents. Differences were found among the difference plasticizer contents in failure types between the denture base resin and soft denture liners. The results suggest that the tensile bond strengths of heat-cured acrylic soft denture liners to the denture base resin were lower with an increase in plasticizer content.

Background: One of the most common problem associated with the used of soft denture lining material is microorganisms and fungal growth especially Candida albicans, which can result in chronic mucosal inflammation. The aim of this study was to evaluate the influence of chlorhexidine diacetate (CDA) salt Incorporation into soft denture lining material on antifungal activity; against Candida albicans, and the amount of chlorhexidine di-acetate salt leached out of soft liner/CDA composite. Furthermore, evaluate shear bond strength and hardness after CDA addition to soft liner Materials and methods: chlorhexidine diacetate salt was added to soft denture lining material at four different concentrations (0.05%, 0.1% and 0.2% by weight). Four hundred and fifty specimens were made and divided into four groups according to the test to be performed. Disk diffusion test was used to evaluate the antifungal activity of the soft liner/CDA composite after four different periods of incubation in artificial saliva. UV spectroscopy was used to evaluate the amount of accumulative and periodic CDA released in artificial saliva after 2 days, 2 weeks and 4 weeks incubation in artificial saliva. The shear bond strength and shore A hardness was measured after 2 and 4 weeks incubation in artificial saliva and the results were statistically analyzed. Results: All experimental groups showed a highly significant increase in diameter of inhibition zone around the test specimen in compare with control group. The release of Chlorhexidine showed to be dose dependent. The shore A hardness a highly significant increase with the addition of CDA and as for shear bonding strength, the addition of CDA at 0.5% and 1.5% percentage resulted in a highly significant decrease in bond strength, while 2.5% and 3.5% percentage showed non-significant differences in compare with control. Conclusion: soft denture lining material with antifungal properties was the result of CDA salt incorporation which indicate that chlorhexidine was released in affected concentration from soft liner/CDA composite. This incorporation resulted in Hardness increase and did not affect the shear bond strength for 2.5% and 3.5% percentage. Keywords: Soft denture liners, antifungal activity, chlorhexidine diacetate salt.

This study evaluated the effect of thermocycling on the tensile strength and tear resistance of four long-term soft denture liners. One light-activated (Astron Light, AL), two chemically activated (GC Reline Soft, GC; Silagum Comfort, SC), and one heat-cured (Molloplast-B, MLP) soft liner materials were tested. Dumbbell and trouser-leg specimen geometries were used for tensile strength and tear resistance tests, respectively. A total of 120 specimens were prepared. Test specimens for each material (n=5) were subjected to thermal cycling for 1000 and 3000 cycles between 5 degrees C and 55 degrees C in a thermocycler. Before thermocycling, AL gave the lowest tensile strength, while SC exhibited the highest tear resistance value among the materials tested (p < 0.05). Thermal cycling significantly affected the tensile strength of AL as well as the tear resistance values of AL, MLP, and GC materials. This in vitro study revealed that the tensile strength and tear resistance values of the soft liner materials tested varied according to their chemical compositions.

ObjectiveThis present in vitro study evaluates the impact of brushing simulation on the surface roughness of acrylic-based and silicone-based soft denture liners following immersion in two different denture cleansing solutions.Materials and methodsSpecimens of silicone-based and acrylic-based soft liners were fabricated and subjected to a standardized brushing simulation protocol. Soft liners were suspended into the standard template of 40 mm x 15 mm x 10 mm dimensions. Two denture cleansers were employed during simulated brushing. The first group was brushed with Stim Clanden denture cleanser, and the second group with Clinsodent denture cleaning powder. Surface roughness (Ra and Rz values) was recorded before and after the simulation using a profilometer. Data were statistically evaluated using Mann-Whitney U and Kruskal-Wallis tests to determine significant differences.ResultsA statistically marked increase in surface roughness was noted in both liner types after brushing simulation. Silicone-based liners exhibited comparatively better resistance to surface deterioration than acrylic-based liners.ConclusionBrushing simulation with denture cleansers impacts the surface roughness of soft liners, with acrylic-based liners being more susceptible to surface damage. Silicon-based soft liners proved to be effective and more resistant to surface damage.

Management of the protrusive premaxilla in patients with bilateral cleft lip is challenging for the reconstructive team. Several intra- and extraoral orthopedic techniques to reposition the protrusive premaxilla prior to bilateral cleft lip repair have been presented in the literature. A modification to a previously described tissue-borne palatal plate with a latex strap is presented. In the modified plate, the latex strap is replaced by an orthodontic elastomeric chain, and the chain over the prolabium is covered with soft denture liner. This appliance is effective in retracting the premaxilla, noninvasive, easy to construct and adjust, economic, well tolerated by the patient, and accepted by the parents.

Soft denture liners evenly distribute functional loads over denture-bearing tissues. The liners aid in more evenly distributing the pressures of mastication to the underlying tissues by absorbing some of the masticatory forces. The study aimed to evaluate the brushing simulation influence on the surface roughness property of soft-tissue liners. A total of eight samples of Avue brand soft-tissue liners with the composition of varnish base and varnish catalyst were suspended into a standard template extracted and numbered sequentially and surface roughness was calculated using a stylus profilometer. A total of 30,000 cycles brushing were done, where the first group samples were brushed with Colgate toothpaste and the second group brushed with Dabur Red toothpaste using a toothbrush simulator (ZM3.8 SD Mechatronik). The data of both pre- and postbrushing values were recorded manually and statistically uploaded on SPSS software version 22 and values were represented in clustered bar graph forms. The significance value of Ra was 0.321. The significance value of Rq was 0.211. The significance value of Rz was 0.354, hence statistically, insignificant. In the present study, the surface roughness of soft-tissue liners is reduced to a minimal extent after brushing simulation.

This rerandomized clinical trial evaluated the influence of soft liners (SL) on biting force, pain perception, and the oral health-related quality of life (OHRQoL) of complete denture wearers. Twenty-eight completely edentulous patients complaining of ill-fitting lower complete dentures were selected to participate in the study from the Dental Hospital, College of Dentistry, Taibah University. All patients received new complete maxillary and mandibular dentures; then they were randomly divided into two groups (14 patients in each group): the acrylic-based SL group, in which the mandibular denture was lined with an acrylic-based soft liner, and the silicone-based SL group, in which the mandibular denture was lined with a silicone-based soft liner. OHRQoL and maximum bite force (MBF) were assessed in this study before denture relining (baseline), then at one month and three months after relining. The finding showed that both treatment modalities significantly improved the OHRQoL of included patients at one-month and three-month periods compared to baseline records (i.e., dentures before relining) with a statistically significant difference (p < 0.05). However, there is no statistical difference between groups at the baseline, one-, and three-month follow-up periods. Regarding maximum biting force, when acrylic-based SL is compared to silicone-based SL, there is no statistical difference between groups at baseline (75 ± 31 and 83 ± 32 N) and one-month follow-up periods (145 ± 53 and 156 ± 49 N); however, after three months of function, the silicone-based group recorded 166 ± 57 N statistically significant high biting force compared to the acrylic-based group that recorded 116 ± 47 N (p < 0.05). Permanent soft denture liners positively affect maximum biting force, pain perception, and OHRQoL more than conventional dentures. After three months, silicone-based SL outperformed acrylic-based soft liners in maximum biting force, which may indicate better long-term results.

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.