Soft Lining Materials Research Articles

Evaluation of Bond Strength and Dimensional Accuracy of Soft Liner to Microwave Cured Denture Base Material

Today, soft liners are being widely used in dental practices by their application to the inner surfaces of the denture with hopes to evenly distribute any potential uneven forces, and to provide a cushion effect to the oral mucosa of the patient mouth. The aim of this study is to investigate the influence of (a) polymethylmethacrylate (PMMA) denture base material curing technique, (b) Molloplast B soft liner curing technique, and (c) PMMA surface treatment, on the “shear bond strength” (SBS) between the Molloplast B liner and PMMA. A total of 80 samples were used in this study to evaluate the SBS performance of microwave (Nature-Cryl, Acron Gc, Japan) and conventional water bath (Ivoclar triplex, Liechtenstein) curing techniques of PMMA, and to evaluate the curing technique of soft liner material Molloplast B (DETAX,GERMANY). Surface treatment of PMMA was performed for half of the samples using neodymium:yttrium aluminum-garnet Nd:YAG laser, and the other half of the samples were surface-treated using AL2O3 sandblasting method. The results showed that the highest mean value in conventional water bath-cured soft liner was 26.69 MPa, whereas the lowest mean value for microwave-cured soft liner was 15.22 MPa. No significant difference was observed between the SBS performance regarding the PMMA surface treatment and curing techniques. Conventional water bath curing technique for soft liner treatment improved the SBS performance. Regarding the PMMA curing technique, the conventional water bath achieved higher SBS, yet the difference was not statistically significant. Finally, surface treatment using laser improved the SBS compared to sandblasted method, but the improvement here was also statistically insignificant.

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.

Effect of argon plasma and Er:YAG laser on tensile bond strength between denture liner and acrylic resin

Statement of problemThe separation of a denture liner from the denture base can be a clinical problem. Different surface treatments to increase the bond have been evaluated, but studies comparing the effect of argon plasma and erbium-doped yttrium aluminum garnet (Er:YAG) laser on the bond between acrylic resin and a denture liner are lacking. PurposeThe purpose of this in vitro study was to evaluate the effect of argon plasma and Er:YAG laser treatments on the bond strengths of acrylic resin to 2 denture liners. Materials and methodsHeat-polymerized acrylic resin (Acron Duo) was bonded to silicone soft-liner materials (Molloplast B, n=30; Mollosil, n=30) to create control specimens (n=10), argon plasma treatment (n=10), and Er:YAG laser treatment (n=10). Silicone liners were polymerized on resin specimens. The tensile bond strength test was performed with a crosshead speed of 10 mm/min with a 10-N load until failure. Data were analyzed by using the Kruskal-Wallis test and unpaired t test (α=.05). ResultsThe laser group showed significantly higher bond strength than the argon plasma group for both Molloplast-B (P=.001) and Mollosil (P<.001). The highest tensile bond strength values were determined in the laser-treated Molloplast-B group (1.325 ±0.119 MPa) while the lowest bond strength values were determined in the Mollosil control group (0.384 ±0.018 MPa). ConclusionsArgon plasma and Er:YAG laser applications increases the tensile bond strength between soft-liner material and resin. Er:YAG laser treatment results in higher bond strength values than treatment with argon plasma for 1 minute.

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.

Effect of Piper betle extract on anti-candidal activity, gelation time, and surface hardness of a short-term soft lining material.

The purpose of this study was to evaluate anti-candidal activity, gelation time, and surface hardness of a short-term soft lining material incorporated with varying concentrations of Piper betle extract (0.25 to 20% w/w). Agar-diffusion assay was conducted to evaluate an inhibitory effect against Candida albicans. The gelation time was assessed and surface hardness was measured at 2 h and 7 days by Shore AO durometer. A soft liner containing at least 5% w/w of P. betle extract was observed the inhibitory effect against C. albicans. An increasing of P. betle concentrations provided larger inhibition zone. Incorporating 5% w/w of P. betle extract into the soft liner did not significantly alter its gelation time and surface hardness (ANOVA; p>0.05). The optimum composition at 5% w/w of P. betle extract can be used as an additive in the soft liner to provide the anti-candidal activity without significantly affect these two main properties.

In vitro evaluation of physicochemical properties of soft lining resins after incorporation of chlorhexidine

Statement of problemIncorporating chlorhexidine into soft lining materials has been suggested to reduce biofilm development on the material surface and treat denture stomatitis. However, evaluation of the physicochemical properties of this material is necessary. PurposeThe purpose of this in vitro study was to evaluate the physicochemical properties of resin-based denture soft lining materials modified with chlorhexidine diacetate (CDA). Material and methodsTwo soft lining resins were tested, one based on polymethyl methacrylate (PMMA) and the other on polyethyl methacrylate (PEMA), into which 0.5%, 1.0%, or 2.0% of CDA was incorporated; the control group had no CDA. The specimens were stored for 2 hours, 48 hours, 7, 14, 21, and 28 days and then analyzed for polymer crystallinity, Shore A hardness, degree of monomer conversion, residual monomer leaching, and CDA release. Data were analyzed by using a 3-way ANOVA and the Tukey HSD test (α=.05). ResultsThe polymer crystallinity of PEMA and PMMA did not change after CDA incorporation. Shore A hardness increased over time, but not for any CDA concentrations tested after 28 days (P>.05). Considering the degree of conversion, PMMA-based resin showed no statistically significant difference (P>.05). However, PEMA-based resin showed a significant decrease (P<.05), which was reflected in a significant increase in residual monomer leaching from PEMA-based resin with the incorporation of 0.5% and 1.0% CDA (P<.05), mainly in the first 48 hours. PMMA-based resin showed no change in monomer leaching (P>.05). For both resins, the CDA release kinetics were related to monomer leaching; for PEMA-based resin, the values were significantly higher in the first 48 hours (P<.05), and for PMMA-based resin, the values were more sustained up to the last day of analysis. ConclusionsThe incorporation of CDA did not affect the physicochemical properties of soft resins. The properties of PMMA were better than those of PEMA.

Evaluation the Effect of Different Methods of Disinfection on Surface Roughness of Soft Denture Lining Materials

Aims: Aim of the study to evaluate the effect of two different disinfection methods for two periods of time on surface roughness of soft denture lining materials (Vertex and Molloplast-B). Materials and methods : The effect of two disinfection methods ,first chemical disinfection method (which include artificial saliva with saturated salt and artificial saliva with vinegar solution), and second microwave method on the surface roughness of soft denture lining materials for two periods of times (14 and 30 days) was evaluated, One hundred samples were prepared. ANOVA and Duncan,s multiple range test were performed to determine the significant difference among the tested groups at p ≤ 0.05% .Results: The results showed that the lowest value of surface roughness (Ra)value after 14 and 30 days for Vertex soft denture lining material was achieved with the microwave group, while the lowest value of surface roughness (Ra)value after 14 and 30 days for Molloplast-B was achieved with the distilled water. The highest value of surface roughness (Ra) for Vertex soft denture lining material was achieved with vinegar after 14 and 30 days., while for Molloplast-B was achieved with vinegar group after 14 days and with salt group after 30 days. Conclusion : The results of T-test Table showed that there were no statistically significant differences in surface roughness(Ra) value between Vertex and Molloplast -B soft denture lining materials after 14 and 30 days except for microwave group after 14 days at P value ≤ 0.05. Distilled water disinfection has less effect on the property than other chemical disinfection and microwave regimen. The effect of disinfection increase significantly with increasing period of time .

Evaluating the Antifungal Efficacy of Incorporating KappaCarrageenan Powder Into “Heat-Cured, Acrylic-Based Soft Denture Lining Material

Denture stomatitis is one of the serious problems that are related to the continuous use of soft lining material due to the accumulation of microorganisms. It is caused mainly by fungal growth, especially of Candida albicans. It, therefore, becomes necessary to examine the effectiveness of incorporating an antifungal drug into the soft lining material. This study was conducted to investigate the efficacy of adding the kappa-carrageenan powder to heat-cured, acrylic-based soft lining material against Candida albicans adherence. A pilot study was performed to decide the best concentration of kappa-carrageenan to be used with the heatcured, acrylic-based soft liner. Five percentages by weight of kappa-carrageenan powder (0.5, 1, 1.5, 2, and 2.5wt.%) were evaluated and compared with the control group (0wt.%). The Candida albicans adherence test was performed to assess the efficacy of kappa-carrageenan powder in preventing the adherence of Candida albicans. Results showed the 1.5wt.% and 2wt.% groups as having the best effect. The main study included preparing thirty samples and dividing them into three groups based on the percentage of powder of kappa-carrageenan added to the heat-cured acrylic-based soft lining material (control: 0wt.%; experimental: 1.5wt.% and 2wt.%). The purpose of performing Candida albicans adherence test was to evaluate the antifungal efficacy of kappa-carrageenan powder addition, and all the resulted data were analysed using “one-way analysis of variance (ANOVA) and Dunnet T3 post-hoc test at a significance level of p&lt;0.05”. The results of Candida albicans adherence test revealed a highly significant decrease in the values of the adhered Candida albicans cells after incorporation of 1.5wt.% and 2wt.% of kappa-carrageenan powder when compared to the control group (p&lt;0.01). The result of this study suggests that the addition of kappa-carrageenan powder is an effective drug against Candida albicans adherence on the surface of the heat-cured acrylic-based soft lining material, and the addition of 2wt.% is more effective than 1.5wt.%.

In vitro Cytotoxicity of Silver Nanoparticles Incorporated in a Soft Silicone Liner

Introduction: Silver nanoparticles (SNPs) have recently been suggested to increase the antimicrobial properties of soft liner materials. However, their safety remains a matter of debate. This study aimed to evaluate the cytotoxicity of Mucopren® soft silicone liner material (Mucopren; Kettenbach, Germany) incorporated in SNPs. Methods: The SNPs with over 98% purity were added to Mucopren in 0.5, 1, 2, and 3 weight percentage (wt%) concentrations and manually homogenized. The mixture of the pieces of Mucopren plus SNPs and SNPs alone were placed in 96-well plates containing Dulbecco's Modified Eagle Medium culture, FBS, and antibiotics with L929 fibroblasts. Cell viability and biocompatibility were determined after 1, 2, and 3 days of incubation using the methylthiazol tetrazolium assay. Optical density was read by an ELISA reader at 570 nm and compared to those of positive and negative controls. Results: Among Mucopren mixed with different SNPs concentration, the cell toxicity had no significant difference in the same days, and cell toxicity decreased over time (P=0.016). The SNPs alone were less cytotoxic than Mucopren incorporated SNP samples (P>0.05). Conclusion: Within the limitations of this study, the addition of 0.5, 1, 2, and 3wt% concentrations of SNPs to Mucopren did not cause a significant change in its cell toxicity in an in vitro condition

Custom-made ocular prosthesis manufactured with permanent soft denture lining material: An alternative method

The eye plays a vital role as one of the six senses in humans. From vision to expression, it has its various functions. The aim of this study was to suggest a technique using soft denture lining material to improve the retention of an ocular prosthesis in a grossly resorbed orbital cavity to minimizes the trauma of thin, atrophic tissue. An ocular prosthesis restores lost anatomical structures and corrects the cosmetic defect. A custom-made ocular prosthesis is a good alternative as soft denture lining material used during the fabrication of scleral part of ocular prosthesis improves patient comfort by acting as a shock absorber and stress distributor, and yields longer duration of wear. A good alternative of a custom-made ocular acrylic prosthesis is presented here, which had acceptable fit, retention, and esthetics. Fabrication of new ocular prosthesis with permanent soft liner is a novel way to minimize trauma to underlying supporting tissues.

Hardness, compressive strength and resilience of complete denture lining materials: an in situ study

ABSTRACT Objective The aim of this study was to evaluate the in situ hardness, compressive strength and resilience of soft lining materials used in total removable prostheses in different time intervals Methods total of 48 rectangular test specimens (10 x 3 x 2 mm) were fabricated of each of the polyvinylsiloxane-based soft liner (Mucopren Soft) and acrylic resin-based material (Trusoft), which were placed on total removable prostheses bases of 12 volunteers (n = 12). The hardness (Shore A), compressive strength (in MPa) and resilience (in Kgf/cm2) were evaluated in different time intervals: 0, 7, 30 and 60 days, at three different locations of the specimens surface. Results The two-way ANOVA and Tukey test showed that the polyvinylsiloxane-based soft liner presented higher hardness values (p = 0.0113) and higher compressive strength (p=0.0252) than the acrylic resin-based material at immediate and 7 days evaluations. The polyvinylsiloxane-based soft liner presented higher resilience values than the acrylic resin-based material at all times (p = 0.0133). Hardness and compressive strength were similar for both materials at 30 and 60 days evaluations. Conclusions For both materials,there was a tendency for an increase of hardness, compressive strength and resilience over time, influenced by the composition of the tissue conditioner. The polyvinylsiloxane-based soft liner presented higher hardness, compressive strength and resilience than the acrylic resin-based material, specially considering a long-term evaluation up to 60 days.

Surface morphology and in vitro leachability of soft liners modified by the incorporation of antifungals for denture stomatitis treatment.

Objective To evaluate the surface morphology and in vitro leachability of temporary soft linings modified by the incorporation of antifungals in minimum inhibitory concentrations (MIC) for Candida albicans biofilm.Methodology Specimens of soft lining materials Softone and Trusoft were made without (control) or with the addition of nystatin (Ny), miconazole (Mc), ketoconazole (Ke), chlorhexidine diacetate (Chx), or itraconazole (It) at their MIC for C. albicans biofilm. The surface analyses were performed using Confocal laser scanning microscopy after 24 h, 7 days, or 14 days of immersion in distilled water at 37ºC. In vitro leachability of Chx or Ny from the modified materials was also measured using Ultraviolet visible spectroscopy for up to 14 days of immersion in distilled water at 37ºC. Data (μg/mL) were submitted to ANOVA 1-factor/Bonferroni (α=0.05).Results Softone had a more irregular surface than Trusoft. Morphological changes were noted in both materials with increasing immersion time, particularly, in those containing drugs. Groups containing Chx and It presented extremely porous and irregular surfaces. Both materials had biexponential release kinetics. Softone leached a higher concentration of the antifungals than Trusoft (p=0.004), and chlorhexidine was released at a higher concentration than nystatin (p<0.001).Conclusions The surface of the soft lining materials changed more significantly with the addition of Chx or It. Softone released a higher concentration of drugs than Trusoft did, guiding the future treatment of denture stomatitis.

The Effectiveness of Aluminum Potassium Sulfate Micro-Particles Addition into Soft Denture Lining Material on Tensile strength and Peel bond Strength of Soft Denture Lining Material

Naturally available products have been used widely for centuries in handling human disease. The present study aimed to determine the effect of aluminum potassium sulfate addition into the soft liner on tensile strength and peel bond strength. The effect of aluminum potassium sulfate evaluated by two methods, first one include incorporation of KAL (SO4)2 into soft liner monomer in concentration (2%,3% by wt.) while the second method include immersion of soft liner specimens in solution of KAL(SO4)2 in concentration(5%,10% percent) during time periods (0,10 minutes). In conclusions, the results of current study encourage use KAL (SO4)2 within soft liner material

Evaluation of the effect of coating Vertex denture lining ma terial with plant oils on microbial growth and hardness

Aims: To evaluate the effect of surface coating with natural plant oils (Salvia officinalis, ginger and eucalyptus) on Candida growth and the hardness of Vertex denture lining material. Materials and method: Forty five specimens were prepared from soft acrylic lining material, twenty five of which were 10x10x2mm in size for testing antifungal activity, and twenty samples were 20mm in diameter and 12mm in thickness, for testing shore A hardness after coating samples with three types of natural oils (Salvia officinalis, ginger and eucalyptus oils). Significant differences among the groups at (p≤0.05) level of significance were determined statistically with one way analysis of variance and Duncan's multiple range test Result: Antifungal assay showed a significant difference between five groups regarding Candida albicans growth (p≤ 0.05). For the hardness test, comparing different times of storage in water (1, 7, 14, 30 days) revealed a significant difference within all groups (p≤0. 05). While comparing the groups coated with natural oils with the control group, significant differences were found between different times of storage in water (1, 7, 30 day) (p≤0.05), except at 14 days of water storage there was no significant difference between groups (p&gt;0.05). Conclusion: All tested natural oils were effective as fungicidal agents and increased the softness and duration of soft acrylic lining material.

ESTABLISH A MECHANICAL DAMPING MODEL FOR EVALUATING THE SURROUNDING SOFT TISSUE OF DENTAL IMPLANT

Multiple variables have been shown to influence early marginal bone loss around dental implants. Among these factors, the location of the microgap related to the alveolar crest, occlusion, crest module and soft tissue thickness were reported to be important factors for deciding the final outcome of the implant treatment. The purpose of this study was to establish a damping model to simulate the mechanical function of dental implants in the oral cavity. The experimental implant model consisted of a screw-type implant (10[Formula: see text]mm). The implant was placed into epoxy resin which was used to simulate bone tissue. In this study, two kinds of epoxy resin were used: PL-1 (with elastic moduli of 2900[Formula: see text]MPa) and PL-2 (210[Formula: see text]MPa) were used to simulate cortical bone and cancellous bone, respectively. Above bone block, a soft lining material was used to simulate the soft tissue around implant. In addition, two-implant model with various distance between implants were established to discuss the effect of soft tissue effect on the damping factors (DF) of the implant system. A noninvasive impulse-forced vibration technique was used to detect the damping factors of the implant models as previous reported. Briefly, the signal excitation was detected through the micro-phone and sent to the spectrum analyzer. The frequency response was obtained from a vibration-time histogram using Fast Fourier Transform software. The DF value of the signal dental implant model was detected to be [Formula: see text]. This value is closed to the in vivo data that was reported previously. This result showed that the model established in this study is a validated model for damping analysis. Furthermore, the DF value of a dental implant surrounded with 3[Formula: see text]mm soft tissue ([Formula: see text]) is significantly higher than the implant with 2[Formula: see text]mm-surround soft tissue ([Formula: see text]). In addition, implant models with larger interval distance between implants showed higher DF values. According to the results of this study, it is reasonable to suggest that dental implant surrounded with higher amount soft tissue may reduce more vibration amplitude while an occlusal force was applied to a dental implant. This vibration reducing effect may be helpful to reduce alveolar bone resorption around implants.

The Influence of Silica Dioxide and Aluminum Oxide Nano Fillers Reinforced Heat Cured Acrylic Denture Base Material and Thermocycling on Tensile and Shear Bond to Denture Soft Lining Material

Background: Soft lining materials play an important role in modern prosthodonticstreatment because of their capability to restore the inflamed and distorted mucosa.The purpose of the research was to estimate the influence of acrylic denture basereinforcement with silanted nano fillers (Al2O3 and Sio2) separately on tensile andshear bond strength of soft lining material and studying effect of thermo cyclingon bonding strength.Materials and methods: Total 120 specimens were prepared; it divided into 60Specimens for shear bond strength test and 6o specimens for tensile bond strengthtest. Specimens were sub grouped into 30 Specimens without thermo cycling and30 specimens with thermo cycling. Each sub group is consisted from: 10Specimens control, 10 specimens were reinforced with 2 wt% of Al2O3 nano fillersand 10 specimens were reinforced with 5 wt% of SiO2 nano fillers. Samples wereprocessed depending on test applied. Soft lining material was applied for eachtesting group. Samples were immersed in distal water for 24 hours at 37°C beforetesting. For thermo cycling test, specimen were thermo cycled in thermo cyclingdevice. Bonding strength test was done using INSTRON universal testingmachine.Results: reinforcement of acrylic denture base with nano-fillers was significantlyincrease both tensile and shear bonding of lining material and thermo cyclingdecreases both bonding strength.Conclusion: reinforcement of acrylic denture base with nano fillers could improvebonding strength of lining material, while thermo cycling had a deleterious effecton bonding strength.

Effect of Alcohol and Tea on Solubility of Soft-liner and Polymethyl Methacrylate Resin: An In Vitro Study

To evaluate solubility of soft denture liner material and acrylic denture base resin when stored in 8% and 50% concentration of alcohol and tea(with milk and green tea) at an interval of 4,7,11 and 15 days. An in vitro study wasdone on 75 standardized samples in disk form (15 mm × 2 mm), each for soft-liner and acrylic denture base resin. Samples were divided into 5 groups (15 per group/per material) and stored in distilled water (A), 8% alcohol (B), 50% alcohol (C), tea with milk (D) and green tea (E). Solubility was determined at each time interval by dividing difference of weight (taken after drying the sample in a desiccator) from day 1 divided by surface area of the specimen. For each day (i.e., 4, 7, 11 and 15),one-way analysis of variance (ANOVA) test was used to determine if the distribution of mean solubility was similar in five groups followed by post-hoc Tukey's test for pair-wise comparisons. Mean solubility of soft-liner was the highest tea with milk (D) followed by green tea (E), then 50% and 8 % alcohol (C and B) and was least in group A at each time of measurement. Mean solubility of an acrylic resin was highest for 8% alcohol (B) and all other groups it was similar. This study shows increased solubility for soft-liners when immersed in tea with milk, green tea, and alcohol at 8% and 50% concentration. The solubility of acrylic resin also increases at 8% alcohol concentration. Drinks/beverages used in our study are commonly consumed, the results of this study caution for restricting the frequency of intake. However, this needs to be confirmed by in-vivo studies designed to prove the association of denture life with the consumption pattern of these drinks/ beverages.

Evaluation the Effects of Incorporation of Silver Nitrate on Some Mechanical Properties of Soft Liner Materials

Evaluation the Effects of Incorporation of Silver Nitrate on Some Mechanical Properties of Soft Liner Materials

A Comfortable Palatal Delayed Surgical Obturator for Hemimaxillectomy Patients

A surgical obturator prosthesis is commonly used as an effective means for rehabilitating patient with hemi-maxillectomy defect. The obturator supports the soft tissues after surgery and minimizes the contraction of scar and disfigurement thereby making a positive effect on patient’s overall function and psychology. The goal of prosthodontics to restore missing orofacial structures for improving facial esthetics and oral function for such patients. The inability to achieve adequate retention, stability, support and comfort due to the friability of healing tissues are the common problems associated with prosthetic treatment in the initial phase of treatment. This case report demonstrates a simple technique to overcome such difficulties by the use of soft lining materials in the delayed surgical obturator.

Evaluation of Thermal Conductivity and Some Other Properties of Heat Cured Denture Soft Liner Reinforced by Halloysite Nanotubes

This study aimed to assess the effect of halloysite nanotubes(HNTS) addition into soft denture lining material on thermal conductivity and thermal diffusivity, shear bond strength, tear strength, and surface roughness of the lining material. HNTS with 0.75% and 1% concentration by weight (according to the pilot study) were added into acrylic-based heat cured soft denture liner. One hundred and twenty different specimens were prepared and divided into four groups according to the test to be performed. The thermal conductivity and thermal diffusivity of the soft liner/ HNTS composite were evaluated, shear bond strength, tear strength, and surface roughness were also measured, the results showed that there was a highly significant increase in thermal conductivity of the experimental specimens in comparison with the control specimens and a non-significant change in the thermal diffusivity of the experimental specimens. The shear bond strength between the soft liner and the acrylic denture base and tear strength showed a highly significant increase, but a non- significant difference in the surface roughness test was observed in all experimental specimens. Thus it can be concluded that the addition of HNTS can provide soft liner material with improved thermal conductivity, shear bond strength and tear strength while thermal diffusivity and surface roughness were non-significantly changed when the concentration of HNTs nanoparticles increased.