Resilient Lining Materials Research Articles

Microbial evaluation of heat cured silicone versus heat cured acrylic resin in maxillary obturator

PurposeThe aim of this trial was to compare the microbial colonization of heat-cured silicone and heat-cured acrylic resin in obturators restoring acquired maxillary defects.Material and methodsThe experiment was carried out on six partially edentulous patients having unilateral total maxillectomy defects approaching midline (class I Aramany classification) who are in need of definitive obturator. Selected patients received metal framework prosthesis with heat-cured acrylic resin bulb extending into the surgical site. At the time of delivery, a swab was obtained from the patients who represent the baseline for the group I. Patients were recalled after two and four weeks from wearing the obturator for microbiological evaluation and a swab was taken each time from the same place. In group II, the heat-cured acrylic resin was replaced with heat-cured silicone and a swab was obtained on the day of insertion as a baseline for group II. Patients were recalled after two and four weeks from the insertion of the relined obturator for microbiological evaluation and a swab was taken each time from the same place. Swabs were obtained from the nasal surface of the surgical defect and immediately cultivated into three different media Blood Agar, Sabouraud Dextrose Agar, and Macconkey media and incubated for microbiological evaluation. The identification and quantification of the isolated microorganisms were performed using the conventional microbiological cultivation method. Finally, the collected data were tabulated and statistically analyzed.ResultsStatistical analysis of the collected data showed, that the difference between the two groups was insignificant. However, patients were more satisfied with obturators lined with heat-cured silicone.ConclusionIt was concluded that within the limitations of this study, both acrylic resin and resilient lining materials could be used as a material for obturator construction in maxillofacial cases. However, longer follow-up period might show different results.

The Effect of Sandblasting on Bond Strength of Soft Liners to Denture Base Resins: A Systematic Review and Meta-Analysis of In Vitro Studies.

Objectives This study aimed to evaluate the effect of sandblasting on the bond strength of denture base resin to soft liners. Materials and Methods This report follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, Embase, Cochrane, Scopus, and OpenGrey databases were searched for in vitro studies that compared sandblasting with no treatment in terms of the tensile, shear, and peel bond strength of resilient lining materials (acrylic-based or silicone-based) to polymethyl methacrylate denture base resin. Based on the outcome, the analysis was carried out in three groups of tensile, shear, and peel bond strength. Subgroup analysis was done for the effect of size of particles on sandblasting, blasting pressure, and type of soft liner whenever possible. Heterogeneity was evaluated among the studies, and meta-analysis was performed with random effect models (p < .05). Results After screening, 16 articles met the inclusion criteria for meta-analyses. No treatment showed significantly higher tensile (p < 0.001) or peel (p=0.04) bond strength, although shear bond strength of sandblasted resin was significantly better (p=0.008). Results of subgroup analyses of particle size favored the control group in 50 µ Al2O3 particle size (p < 0.001). In analyses of blasting pressure, the control group had significantly better tensile bond strength than specimens with blasting pressure ≤1 bar (p < 0.001) while specimens with blasting pressure beyond 1 bar showed significantly more tensile strength than control group (p=0.03). In silicon-based liners, groups without any surface treatment had significantly higher tensile bond strength (p < 0.001). Conclusion According to the in vitro studies, sandblasting would not lead to significant increase in bond strength of soft liner to the denture base resin.

BASIC PROBLEMS WITH THE USE OF RESILIENT DENTURE LINING MATERIALS: LITERATURE REVIEW

Complicated cases in the treatment of totally edentulous patients, as well as in the fabrication of obturators and epitheses, require the use of resilient lining materials (RLMs). These materials have several disadvantages, which is why many dental practitioners do not recommend them. The tendency to breaking the bond between the hard acrylic resin and the resilient liner is a fact with unpleasant consequences, mainly found with the use of cold-curing silicone-based resilient liners. Methods to improve the bond between the hard denture base and the RLM have been the subject of numerous publications. The efforts of the authors are focused in two directions: mechanical or chemical treatment of the denture base or a combination of both. Other commonly discussed problems with the use of RLMs are the difficult and even impossible repair and the retention of oral fluids, fungi and other microorganisms due to the porosity of RLMs. Despite the wide variety of tools offered by different manufacturers, the issue of optimal and high-quality mechanical treatment of the polymerized resilient material has not yet been fully resolved.

APPLICATION OF RESILIENT DENTURE LINING MATERIALS: LITERATURE REVIEW

Clinical cases of excessive bone resorption, presented thin, non-pliable mucosa, exostosis or painful neurogenic points require more specific methods for treatment with removable dentures. Specialized scientific literature discusses various materials and technologies for solving these problems. The use of resilient lining materials (RLMs) for partial and complete dentures is a possible solution if there are clear clinical indications and appropriate selection of the type of material. The purpose of this review is to provide and analyze up-to-date literature data on the use of resilient materials for partial and complete denture lining. Material and Methods: An electronic search in PubMed, Google, EBSCOhost and Science Direct databases was conducted from January to December 2019. Results: Resilient lining materials have a variety of applications. They can be used in complete and all types of partial edentation, i.e. Classes I, II, IV and VI by Kennedy - Popov. The indications for use are different for the two RLMs groups, i.e. temporary (short-term) and permanent (long-term) lining materials. A number of authors have identified them as materials for the limited application. They consider that their use is justified only in the case of the severely atrophied alveolar ridge, in obturators and epitheses. Conclusion: Resilient lining needs to be considered and planned in advance. It should not be used to compensate for errors in denture design. Appropriate selection of a material for the particular clinical case is of crucial importance.

Hydraulic conductivity of bentonite-polymer composite geosynthetic clay liners permeated with bauxite liquor

The high ionic strength of the porewater in red mud (bauxite liquor from digestion) can suppress swelling of montmorillonite, resulting in geosynthetic clay liners (GCLs) that are too permeable to be effective as liners in red mud disposal facilities. Bentonite-polymer composite GCLs (BPC GCLs) have been developed as more resilient lining materials, and some BPC GCLs have been shown to have very low hydraulic conductivity to bauxite liquors that have extreme ionic strength and pH. In this study, a nationwide investigation was conducted in China to evaluate the characteristics of bauxite liquor in Chinese impoundments, and to evaluate the suitability of GCLs containing granular sodium bentonite or BPCs for containment. Hydraulic conductivity tests were conducted on six BPC GCLs with two characteristic Chinese bauxite liquors that are hyperalkaline (pH > 12) and had ionic strengths of 76.9 mM and 620.3 mM. The BPC GCLs had hydraulic conductivity ranging from 10−8-10−12 m/s, which is higher than the hydraulic conductivity of BPC GCLs to deionized water (10−12-10−13 m/s), but lower than the hydraulic conductivity of conventional GCLs with granular sodium bentonite GCLs to the same liquors (10−7-10−8 m/s). The hydraulic conductivity of the BPC GCLs depends on the chemical properties of the leachate, the polymer loading, and the type of polymer. Microstructural analysis by scanning electron microscopy (SEM) suggests that the hydraulic conductivity of BPC GCLs is controlled by pore-blocking by polymer hydrogel, which is affected by the bauxite liquor.

Comparative evaluation of physical properties of commercially available silicone-based soft denture liners and acrylic-based soft denture liners

Elastic materials used in dental prosthetics to line removable dentures should be characterized by biocompatibility toward oral tissues, shape, and color stability; resistance to abrasion; and durability of the junction between the lining and the denture. The resilient lining materials present problems during clinical use, such as weakening of bond between lining and denture loss of resiliency, color alterations, and porosity. This review was aimed to compare and evaluate the physical properties of soft denture liners acrylic and silicone based and to determine which denture liners would be best suited for clinical usage. A review protocol was structured on the basis of the guidelines proposed by the PRISMA statement and Centre for Reviews and Dissemination. Overall, the results indicated that silicone-based soft denture liners performed significantly better than acrylic-based soft denture liners when compared for color stability, surface hardness, tensile bond strength, water sorption, and solubility, concluding that silicone-based soft liners would be better for long-term clinical use.

Bond Strength of Resilient Lining Materials to Denture Base Resin: A Systematic Review and Meta-Analysis.

Bond strength of resilient lining materials with denture base materials is continuously under development. The purpose of this systematic review is to perform a meta-analysis to find out which form of resilient lining bonds better to the denture base, what surface treatments have the highest efficacy to increase the bonding, and what is the most commonly preferred test method to measure bond strength. Based on a search of PubMed, EMBASE, and Google Scholar, 57 articles were included in this study. A meta-analysis was performed on the results of the 57 articles. The most commonly used test method was the tensile test. Effective surface treatments for bond strength vary depending on the type of the test applied and the type of the attached resilient lining material. Silicone-based resilient lining materials are more commonly preferred than acrylic-based resilient lining materials. While chemical agents and chemicals of resilient lining materials were the most commonly applied surface treatments, a very limited number of studies preferred applying CoJet and laser. The efficacy of surface treatments varies depending on the resilient lining materials and the test type. More successful results can be achieved by selecting the appropriate surface treatment according to the type of the resilient lining material to increase the bond strength. In particular, when used alone, laser appears to be more effective. Chemical agents and laser are the most effective surface treatments for both silicone- and acrylic-based liners. Moreover, new studies are required to determine the efficacy of CoJet. These findings should help clinicians select a suitable surface treatment to increase the bond strength of resilient lining materials to denture base materials.

A combination technique for relining removable prostheses

The two major types of resilient lining material include acrylic based lining material and silicone based lining material. Both these materials have few inherent disadvantages associated with them. A technique for overcoming the disadvantages of both the acrylic and silicone based lining materials by using them in a combination is presented in this article.

Advances in Soft Denture Liners: An Update.

Soft denture liners are used in complete and partial removable dentures to distribute functional loads homogeneously on the denture-bearing tissues. These materials are recommended in cases of irregular bone resorption, bony undercuts, thin atrophic mucosa, immediate prosthesis, healing after implant placement, and for patients with bruxism and xerostomia. The resilient lining materials can be categorized as plasticized acrylic resins or silicone elastomers. The plasticized acrylic resin comprises of acrylic polymers and copolymers, a liquid containing an acrylic monomer and plasticisers, such as ethyl alcohol and/or ethyl acetate responsible for preserving the material softness. The silicone elastomers, consisting of dimethylsiloxane polymers, with a chemical composition similar to that of the silicone impression materials devoid of leachable plasticisers, retain their elastic properties for prolonged periods. Most of the currently available materials have several disadvantages, including color stability, long-term resiliency, abrasion resistance, bond strength and porosity. Several modifications have been done recently to overcome of these disadvantages of the soft liners. The current review summarizes the recent developments in soft liners.

Effect of surface treatments on the bond strength of soft denture lining materials to an acrylic resin denture base

Adhesive failure between acrylic resin and resilient liner material is commonly encountered in clinical practice. The purpose of this study was to evaluate the effect of different surface treatments on the bond strength of 2 different resilient lining materials to an acrylic resin denture base. Ninety-six dumbbell-shaped specimens were fabricated from heat-polymerized acrylic resin, and 3 mm of the material was cut from the thin midsection. The specimens were divided into 6 groups according to their surface treatments: no surface treatment (control group), 36% phosphoric acid etching (acid group), erbium:yttrium-aluminum-garnet (Er:YAG) laser (laser group), airborne-particle abrasion with 50-μm Al2O3 particles (abrasion group), an acid+laser group, and an abrasion+laser group. The specimens in each group were divided into 2 subgroups according to the resilient lining material used: heat-polymerized silicone based resilient liner (Molloplast B) and autopolymerized silicone-based resilient liner (Ufi Gel P). After all of the specimens had been polymerized, they were stored in distilled water at 37°C for 1 week. A tensile bond strength test was then performed. Data were analyzed with a 2-way ANOVA, and the Sidak multiple comparison test was used to identify significant differences (α=.05). The effects of the surface treatments and resilient lining materials on the surface of the denture base resin were examined with scanning electron microscopy. The tensile bond strength was significantly different between Molloplast B and Ufi Gel P (P<.001). The specimens of the acid group had the highest tensile bond strength, whereas those of the abrasion group had the lowest tensile bond strength. The scanning electron microscopy observations showed that the application of surface treatments modified the surface of the denture base resin. Molloplast B exhibited significantly higher bond strength than Ufi Gel P. Altering the surface of the acrylic resin denture base with 36% phosphoric acid etching increased bond strength.

Rehabilitation of maxillectomy defect with obturator prosthesis

The acquired defects of the palate are created commonly surgical intervention of benign or malignant neoplasms. The size and location of the defect influence the level of difficulty in prosthetic rehabilitation. Surgical intervention creates anatomic defect which forms communication among the oral cavity, nasal cavity and maxillary sinus. The goal of prosthodontist is to rehabilitate missing oral and extra oral structures with restoration of normal anatomic and physiologic function. Prosthetic rehabilitation with obturator restores the oral structures and also acts as barriers between communications among the cavities. Acquired maxillary defects of the palate are seen in patients suffering from benign and malignant neoplasms, trauma, pathologic changes, radiation therapy and surgical intervention. Ablative surgical therapy is frequently adopted for the control of malignancies and other abnormal growths. This results in anatomic defect that allows the oral cavity maxillary sinus and nasal cavity to become one compartment, abrupt alteration of physiologic functions such as speech, mastication, deglutition and salivary control. Prosthodontics rehabilitation for an acquired maxillary defect begins immediately at the time of surgical resection. Prosthetic rehabilitation begins with a surgical obturator, which is inserted at the time of surgery to help retain the packing, prevent oral contamination of the surgical wound and skin graft, and to allow the patient to speak and swallow during the initial post operative period. The surgical obturator is commonly converted into an interim obturator with the addition of resilient lining material to adapt to the defect. Definitive obturator is initiated approximately 3 to 4 months after surgery when healing is complete. The impression for definitive obturator prosthesis should include the skin graft mucosal junction, lateral aspect of the orbital floor, and the dynamic physiology of the velopharyngeal mechanism during speech and swallowing. The obturator bulb must also be contoured to prevent obstruction of nasal breathing and to maintain nasal resonance during speech. The degree of extension into the defect varies depending upon the configuration of the defect, character of its lining tissue, and functional requirement for retention, stability and support of the prosthesis. This article describes a case report of a patient who had undergone partial maxillectomy secondary to squamous cell carcinoma and rehabilitated with definitive obturator.

Effect of denture cleansers on surface hardness of resilient denture liners at various time intervals- anin vitrostudy

PURPOSEThis study was aimed to determine the effect of two chemically distinct denture cleansers and water on the surface hardness of acrylic and silicone based soft denture liners at various time intervals.MATERIALS AND METHODSTwo commonly used commercial resilient liner material were selected based on their chemical composition (silicone- and acrylic-based soft liners) for this investigation. 120 cylindrical specimens were made of 15 mm × 10 mm dimensions (according to ASTM: D-2240-64T) in a custom made metal mold. All specimens were stored in artificial saliva throughout the study. Forty specimens were cleansed daily in 0.5% sodium hypochlorite solution; forty were cleansed in sodium perborate and remaining forty specimens were daily rinsed in water. Testing was done at 1 week, 1 month, 3 months and 6 months for surface hardness using a Shore A Durometer. A mean of 3 reading for each sample was subjected to one-way ANOVA, Post Hoc test and pair-t test for statistical analysis. P values of less than 0.05 were taken as statistically significant.RESULTSSurface hardness of all the samples was significantly higher after a period of 6 months irrespective of the cleansing treatment. Minor changes were observed between control, sodium hypochlorite and sodium perborate groups with time. Greater change was observed in surface hardness of acrylic-based soft denture liners as compared to silicone-based soft liners for all groups, as time progressed.CONCLUSIONSilicone-based soft denture liners performed significantly better in all cleansing treatments than acrylic-based soft denture liners.

Cytotoxicity of denture base and hard chairside reline materials: A systematic review

Adverse reactions to the materials used for the fabrication and reline of removable denture bases have been observed. The purpose of this study was to systematically review the published literature on the cytotoxicity of denture base and hard reline materials. MEDLINE via PubMed, Google Scholar, and Scopus databases for the period January 1979 to December 2009 were searched with the following key words: (biocompatibility OR cytotoxic* OR allergy OR "burning mouth" OR "cell culture techniques") AND ("acrylic resins" OR denture OR monomer OR relin* OR "denture liners"). The inclusion criteria included in vitro studies using either animal or human cells, in which the cytotoxicity of the denture base and hard chairside reline resins was tested. Studies of resilient lining materials and those that evaluated other parameters such as genotoxicity and mutagenicity were excluded. Articles published in the English language and in peer-reviewed journals focusing on the cytotoxicity of these materials were reviewed. A total of 1443 articles were identified through the search. From these, 20 studies were judged to meet the selection criteria and were included in the review. In the majority of the studies, continuous cell lines were exposed to eluates of specimens made from the materials, and mitochondrial activity was used to estimate cell viability. The tested acrylic resins were grouped according to 5 major categories: (1) heat-polymerized; (2) microwave-polymerized; (3) autopolymerizing; (4) light-polymerized; and (5) hard chairside reliners. This review provided some evidence that the heat-polymerized resins showed lower cytotoxic effects than autopolymerizing denture base acrylic resins and light or dual polymerized reline resins. However, because of the large number of variables in the reviewed literature, a definitive conclusion could not be drawn.

Effect of different surface treatments on tensile bond strength of silicone-based soft denture liner

Failure of the bond between the acrylic resin and resilient liner material is commonly encountered in clinical practice. The purpose of this study was to investigate the effect of different surface treatments (sandblasting, Er:YAG, Nd:YAG, and KTP lasers) on tensile bond strength of silicone-based soft denture liner. Polymethyl methacrylate test specimens were fabricated and each received one of eight surface treatments: untreated (control), sandblasted, Er:YAG laser irradiated, sandblasted + Er:YAG laser irradiated, Nd:YAG laser irradiated, sandblasted + Nd:YAG laser irradiated, KTP laser irradiated, and sandblasted + KTP laser irradiated. The resilient liner specimens (n = 15) were processed between two polymethyl methacrylate (PMMA) blocks. Bonding strength of the liners to PMMA were compared by tensile test with the use of a universal testing machine at a crosshead speed of 5 mm/min. Kruskal-Wallis and Wilcoxon tests were used to analyze the data (α = 0.05). Altering the polymethyl methacrylate surface by Er:YAG laser significantly increased the bond strengths in polymethyl methacrylate/silicone specimens, however, sandblasting before applying a lining material had a weakening effect on the bond. In addition, Nd:YAG and KTP lasers were found to be ineffective for increasing the strength of the bond.

Evaluation of colour change of resilient liner materials in different solutions

Colour stability is one of the most important clinical properties for resilient liner materials, and colour changes could be an intelligible indictor to operators of ageing or damaging of the materials. The aim of this paper was to measure the colour stability of four resilient liner materials in vitro, by storing them in different solutions. The colour changes of 36 specimens (2 mm in thickness and 15 mm in diameter) were determined after 6, 12 and 24 h of immersion into mouthwash (Andorex, Kim Pa, Istanbul, Turkey). Distilled water was used as a control. One hundred and forty-four specimens were evaluated after 1 week, and after 1 and 3 months' storage in other solutions. Colour changes of the specimens were determined using a Jeanway colorimeter (Model 6030). The colour measurements were compared using one-way analysis of variance and least significant difference (LSD) multiple range test (α=0·05). The colour change of Molloplast-B was not noticeable and Visco-gel was found to be significantly different at all comparative time interval measurements (p<0·05). Silicone type resilient liner materials seem to be more resistant to colour change and harder than resilient liners of acrylic type.

Research projects related to complete dentures published in 2008 by members of the Japan Prosthodontic Society

This article reviews the findings of the original papers related to complete dentures published in the Journal of the Japan Prosthodontic Society (Nippon Hotetsu Shika Gakkai Zasshi), Vol. 52, 2008. A total of six articles focused on complete dentures or materials related to complete dentures were selected and summarized. A variety of subjects in relation to removable prosthodontics were discussed in the articles, including denture plaque control, resilient denture lining materials or denture adhesives, and assessment and/or anatomical analysis of prognosis of complete dentures.

In Vitro Changes in Hardness of Sealed Resilient Lining Materials on Immersion in Various Fluids

During clinical use, resilient lining materials undergo changes in hardness that make them ineffective. The aims of this investigation were (1) to determine the effect of a resilient lining sealer on the hardness of four resilient denture liners; and (2) to determine the effect of the sealer on hardness after immersion in various solutions. Two sets of specimens of four resilient liners, Coe-comfort (CC), PermaSoft (PS), Tokuyama soft reline (TK), and Total-Soft (TS), 6-mm diameter by 4-mm thickness, were fabricated. Two coats of Permaseal, a soft reline sealant, were applied to one set of specimens of each material according to manufacturers' instructions. Sealed and unsealed samples were divided into four groups (n = 10). Each group was immersed in one of the following solutions: artificial saliva at 37 degrees C, Efferdent, Efferdent with once daily scrubbing with a soft toothbrush, and 50% ethanol. Shore A hardness numbers were obtained at 0, 1, 3, 7, 30, and 90 days. A two-way ANOVA test was performed using materials (treated and untreated) and immersion solution as independent variables. The percentage change in hardness after the 90-day immersion period was the dependent variable. The results show that the application of sealant significantly improved the durability of CC, PS, and TS in immersion solutions by maintaining hardness close to preimmersion values or delaying the softening effect of the solutions. The hardness of sealed and unsealed TK showed the significantly (p < 0.05) lowest change after immersion in the test solutions. Ethanol caused the most severe decrease in hardness of all solutions, followed by saliva. Immersion in Efferdent and daily brushing after immersion in Efferdent showed only a mild effect on the hardness of the soft reline agents. The use of a sealer can play an important role in the preservation of the hardness of some resilient lining materials.

Effect of storage duration on the hardness and tensile bond strength of silicone- and acrylic resin-based resilient denture liners to a processed denture base acrylic resin

Two potential problems commonly identified with a denture base incorporating a resilient liner are a failure of the bond between the acrylic resin and resilient liner material and a loss of resiliency of the resilient liner material over time. This investigation evaluated the effect of storage duration on the tensile bond strength and hardness of acrylic resin- and silicone-based resilient liners that were either heat- or autopolymerized onto denture base acrylic resin. The denture liners investigated were a definitive acrylic resin-based heat-polymerized (Vertex Soft), interim acrylic resin-based autopolymerized (Coe-Soft), definitive silicone-based heat-polymerized (Molloplast-B), and definitive silicone-based autopolymerized (Mollosil Plus) resilient liner. The resilient liners were processed according to manufacturers' instructions. The resilient liner specimens for tensile bond strength testing (n=10) were 10 x 10 x 3 mm and were processed between 2 polymethyl methacrylate (PMMA) (Meliodent) blocks (40 x 10 x 10 mm). The resilient liner specimens for hardness testing (n=10) were 20 mm in diameter and 12 mm in height. Specimen shape and liner thickness were standardized. Specimens were stored for 1 day, 1 week, or 1, 3, or 6 months in water at 37 degrees C. Tensile bond strength was measured in a universal testing machine at a crosshead speed of 20 mm/min, and hardness was measured using a Shore A durometer. Two-way ANOVA and Tukey HSD tests were used to analyze the data (alpha=.05). The results indicated that there were significant differences both in the hardness and bond strength values of resilient liner materials. The definitive silicone-based heat-polymerized (Molloplast-B) resilient liner had significantly higher bond strength and lower hardness values than the others. Prolonged exposure to water produced significantly higher hardness values and lower bond strength values. Within the limitations of this in vitro study, specimens of resilient liners immersed in water demonstrated significantly (P<.001) lower bond strength values and higher hardness values over time.

Adherence of Candida albicans to denture base acrylics and silicone-based resilient liner materials with different surface finishes

This study evaluated the surface roughness and Candida albicans adherence on denture base acrylic resins and silicone-based resilient liners with different surface finishes. Four commercial denture base acrylic resins (three heat polymerized and one room temperature polymerized) and five silicone-based liner materials (two heat polymerized and three room temperature polymerized) (10 x 10 x 2 mm) were tested in this study. The materials were processed against glass or plaster or finished with a tungsten carbide bur. Surface roughness measurements were made using a profilometer with an optical scanner probe. All specimens were ultrasonically cleaned in water for 15 s, autoclave sterilized, and contaminated with C. albicans solution for adherence assay evaluation. The materials processed against the glass surface showed significantly lower surface roughness values (0.11 +/- 0.1-1.66 +/- 1.1 microm) than those of the materials processed against the dental plaster (2.61 +/- 0.2-6.12 +/- 2.8 microm) or roughening with a bur (1.48 +/- 0.2-7.05 +/- 1.2 microm; p < 0.05, one- or two-way analysis of variance). Also, the materials processed against the glass surface showed lower C. albicans adhesion (mean ranks 120.36) than those of the materials processed against the dental plaster (mean ranks 139.77) or roughening with a bur (mean ranks 143.06), but the differences were not statistically significant (p > 0.05, Kruskal-Wallis and Mann-Whitney). In all types of surface finishes, C. albicans adhesion on denture base acrylics was significantly less (mean ranks 90.18-90.40) than those of silicone liners (mean ranks 119.38-205.18; p < 0.01, Kruskal-Wallis).

The effects of maleic anhydride terpolymer and its ester derivatives on tensile bond strength between the acrylic resin and resilient lining material

AbstractThe present study investigated the effects on the bonding between the denture base acrylic resin and the soft silicon based lining material of maleic anhydride‐styrene‐vinyl acetate (MA‐St‐VA) terpolymer and some of its ester derivatives. These ester derivatives were n‐propylmaleate‐styrene‐vinyl acetate (n‐PrMA‐St‐VA), n‐buthylmaleate‐styrene‐vinyl acetate (n‐BuMA‐St‐VA) and n‐benzylmaleate‐styrene‐vinyl acetate (n‐BzMA‐St‐VA). Fourier Transform infrared spectroscopy method was used to determine interactions between terpolymers with the acrylic resin and soft lining material. The tensile bond strength of all the groups was compared and the obtained differences were statistically significant (P &lt; 0.05). The highest value was found for the samples lined with n‐BuMA‐St‐VA (2.11 ± 0.21 MPa) and the samples lined with n‐BzMA‐St‐VA had the lowest bond strength (0.3 ± 0.12 MPa). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1338–1341, 2007