Resilient Liner Research Articles

Investigation of bonding properties of denture bases to silicone-based soft denture liner immersed in isobutyl methacrylate and 2-hydroxyethyl methacrylate.

PURPOSEThe purpose of this study was to investigate the bonding properties of denture bases to silicone-based soft denture liners immersed in isobutyl methacrylate (iBMA) and 2-hydroxyethyl methacrylate (HEMA) for various lengths of time.MATERIALS AND METHODSPolymethyl methacrylate (PMMA) test specimens were fabricated (75 mm in length, 12 mm in diameter at the thickest section, and 7 mm at the thinnest section) and then randomly assigned to five groups (n=15); untreated (Group 1), resilient liner immersed in iBMA for 1 minute (Group 2), resilient liner immersed in iBMA for 3 minutes (Group 3), resilient liner immersed in HEMA for 1 minute (Group 4), and resilient liner immersed in HEMA for 3 minutes (Group 5). The resilient liner specimens were processed between 2 PMMA blocks. Bonding strength of the liners to PMMA was compared by tensile test with a universal testing machine at a crosshead speed of 5 mm/min. Data were evaluated by 1-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (α=0.05).RESULTSThe highest mean value of force was observed in Group 3 specimens. The differences between groups were statistically significant (P<.05), except between Group 1 and Group 4 (P=.063).CONCLUSIONImmersion of silicone-based soft denture liners in iBMA for 3 minutes doubled the tensile bond strength between the silicone soft liner and PMMA denture base materials compared to the control group.

Conservative approach for the treatment of geriatric edentulous patient with grossly resorbed mandibular ridge

The construction of complete denture prosthesis for a geriatric patient with grossly resorbed mandible has always been a challenge to our profession. Poor mandibular ridges accompanied by thin and atrophic oral mucous membrane leads to increased bruising and damage under occlusal loading. Nutrition and diet play an important role in all edentulous patients, but particularly with the geriatric patient. This case report presents a conservative prosthodontic option that includes a modifi ed fi nal impression technique using admixed compound followed by permanent lining of the mandibular denture with a heat-cure silicone-based resilient soft liner along with dietary counseling.

The influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge. A 5‐year randomised clinical trial

This study aimed to compare the influence of resilient liner and clip attachments for bar-implant-retained mandibular overdentures on opposing maxillary ridge after 5 years of denture wearing. Thirty edentulous male patients (mean age 62·5 years) received two implants in the anterior mandible after being allocated into two equal groups using balanced randomisation. After 3 months, implants were connected with resilient bars. New maxillary complete dentures were then constructed, and mandibular overdentures were retained to the bars with either clips (group I, GI) or silicone resilient liners (group II, GII). The prosthetic and soft tissue complications of the maxillary dentures were recorded 6 months (T6 m ), 1 year (T1), 3 years (T3) and 5 years (T5) after overdenture insertion. Traced rotational tomograms were used for measurements of maxillary alveolar bone loss. The proportional value between bone areas and areas of reference not subject to resorption was expressed as a ratio (R). Change in R immediately before (T0) and after 5 years (T5) of overdenture insertion was calculated. Maxillary denture relining times and frequency of flabby anterior maxillary ridge occurred significantly more often in GI compared with GII. The change of R in anterior part of maxilla was significantly higher than change of R in posterior part in both groups. GI showed significant resorption of anterior residual ridge compared with GII. Relining times and frequencies of flabby ridge were significantly correlated with change in R. Within the limitations of this study, resilient liner attachments for bar-implant-retained mandibular overdentures are associated with decreased resorption and flabbiness of maxillary anterior residual ridge and fewer maxillary denture relining times when compared with clip attachments.

Comparative Evaluation of Tensile Bond Strength between Silicon Soft Liners and Processed Denture Base Resin Conditioned by Three Modes of Surface Treatment: An Invitro Study

Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40mm in length; 10mm in width and 10mm in height (40×10×10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3mm thick; 10mm long and 10mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base.

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.

The Sandwich Denture—A Novel Way to reduce Ridge Resorption

ABSTRACT Many edentulous patients with severely resorbed ridge complain of loss of retention and discomfort with the use of conventional complete dentures. Basic principles of retention, stability and support are lost in these patients as overlying mucosa is thin and nonresilient. This article describes a case report of a 52-year-old completely edentulous female patient with severely resorbed mandibular ridge where a novel technique was used by sandwiching a layer of permanent soft resilient liner (Molloplast-B) between the denture teeth and denture base to reduce traumatic impact of masticatory forces on residual ridges and thereby reducing the residual ridge resorption. The resilient layer acts as a ‘shock absorber’ or ‘stress distributor’. How to cite this article Bansal S, Aras M, Chitre V. The Sandwich Denture—A Novel Way to reduce Ridge Resorption. Int J Prosthodont Restor Dent 2013;3(2):68-71.

Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin

In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties.ObjectiveThis study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply). Material and MethodsAcrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37ºC for 48 h. The drug powder concentrations (nystatin 500,000U - G2; nystatin 1,000,000U - G3; miconazole 125 mg - G4; miconazole 250 mg - G5; ketoconazole 100 mg - G6; ketoconazole 200 mg - G7; chlorhexidine diacetate 5% - G8; and 10% chlorhexidine diacetate - G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers' instructions and stored in distilled water at 37ºC for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (α=0.05) and the failure modes were visually classified. ResultsNo significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups. ConclusionsPeel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents.

Candida colonisation and the efficacy of chlorhexidine gluconate on soft silicone‐lined dentures of diabetic and non‐diabetic patients

The aim of this study was to evaluate Candida colonisation in the dentures with silicone soft liner in diabetic and non-diabetic patients and to assess the antifungal efficacy of chlorhexidine gluconate on Candida colonies. Thirty patients with resorbed ridges, fifteen each in the diabetic and non-diabetic group, were selected. The mandibular denture of each patient was lined with heat-polymerised silicone resilient liner. Patients were instructed to clean the dentures with soap water and brush. Samples from the fitting surface of mandibular dentures were collected at 15, 21 and 30 days. Subsequently, samples were collected at 15, 21 and 30 days, after cleaning the dentures with a detergent solution of 4% chlorhexidine gluconate, and incubated for the evaluation of Candida growth. These data were subjected to statistical analysis by Mann-Whitney U-test. Normal oral flora in diabetics and non-diabetics showed no difference (p > 0.05). The density of colonies increased after 21 and 30 days in diabetic patients (p < 0.05). Number of Candida colonies significantly reduced in both the groups after 21 and 30 days of cleaning the dentures with 4% chlorhexidine gluconate (p < 0.05). Dentures with silicone resilient liner exhibit increased Candida growth in diabetic patients. Four per cent chlorhexidine gluconate solution effectively disinfects these dentures.

Fabrication of a functional palatal saliva reservoir by using a resilient liner during processing of a complete denture

One of the major problems associated with xerostomic patients is the poor tolerance and retention of removable dental prostheses because of thin dry atrophic mucosa and lack of a saliva film. The use of salivary substitutes can improve lubrication, provide irrigation for dry mucosa, provide significant relief from symptoms, and also improve the retention of removable prostheses. These substitutes can be delivered over prolonged periods by using saliva reservoirs in the prosthesis itself. This report describes a novel technique for the fabrication of a functional palatal saliva reservoir in edentulous xerostomic patients. The technique uses a resilient liner in the floor of the reservoir. The tongue presses against the liner during swallowing, resulting in flow of saliva substitute through a hole in the anterior part of the floor of the reservoir.

Nasoalveolar Molding with Active Columellar Lengthening in Severe Bilateral Cleft Lip/Palate: A Clinical Report

Severe bilateral cleft-lip/palate patients are difficult to manage even if nasoalveolar molding therapy is advocated before surgical repair. A 5-day-old male infant with bilateral cleft-lip-palate was managed with the nasoalveolar molding technique. Periodic adjustments of the appliance were continued every week to mold the nasoalveolar complex into the desired shape for the 5 months of infancy. The cleft width of 12 mm on the right and 14 mm on the left side was completely reduced, and the absent columella was lengthened to 6 mm with the active molding appliance. The horizontal bar of the nasal stent of the appliance was modified by adding an additional 1 mm layer of resilient liner on the tissue surface to achieve rapid columellar lengthening. In severe bilateral cleft-lip/palate cases, simple modifications in the appliance can achieve rapid results.

Resilient Liners: A Review

Resilient liners when used intelligently are an excellent adjunct in removable prosthodontics. However, currently they have to be best considered as temporary expedients because none of the advocated permanent liners have life expectancy comparable to resin denture base. This article reviews the literature regarding their composition, functions, gelation characteristics, bond strength and influence on denture bases. It also presents their drawbacks and attempts made to extend their longevity. A Medline search was completed for the period from 1986 to 2007, along with a manual search, to identify pertinent English peer-reviewed articles and textbooks.

Survival analysis of mandibular complete dentures with acrylic‐based resilient liners

The purpose of this long-term randomised controlled trial was to compare the longevity of dentures constructed using a conventional acrylic resin (CAR) to that of dentures constructed using an acrylic-based resilient liner (ARL). The follow-up study was essentially carried out by annual telephone calls to each of the 67 participants. The Kaplan-Meier method and life-table analysis were used for univariate analyses. The Cox proportional-hazards test was used as a final model for statistically adjusting predictor variables such as sex, clinician type, mandibular denture type and age at denture delivery. The denture type was likely to affect the survival time of the dentures, while the sex and clinician type were not. The group using acrylic-based resilient denture liners had twice the risk of having shorter denture-survival times than those using conventional acrylic resin dentures. Younger participants were likely to have a reduced risk of having shorter denture-survival times than older participants. We conclude that mandibular complete dentures constructed using ARL are twice as likely as dentures constructed using CAR to have shorter denture survival times, mainly because of material deterioration.

Effect of the microwave irradiation on disinfection of complete denture lined with soft resilient liner

BackgroundThe fitting surface of denture base promotes accumulation of micro-organisms. The microwave irradiation is used for denture disinfection. It is important therefore to study the effect of different intensities and the exposure time of the microwave irradiation preventing or promoting the accumulation of micro-organisms. The objective of this study aimed to evaluate the effect of microwave irradiation on disinfection of complete denture lined with soft resilient liner. MethodTwenty one edentulous patients were selected from the outpatient clinic of prosthodontics Department, Faculty of Oral and Dental Medicine, Cairo University. Every patient had received upper and lower acrylic complete dentures lined with soft resilient liner which were constructed following the conventional technique. The disinfection of the dentures with microwave for the fitting surfaces of denture bases and mucosa beneath them were swabbed at insertion visit, one week, two weeks & three weeks after denture insertion. Microbial adhesion was determined by counting the colonies forming units (CFU) of the micro-organisms in the collected specimens. Data were tabulated, and statistically analyzed. ResultsThe number of adhering microorganism on denture lined with soft resilient liner was more than number of adhering microorganism to the mucosa. The three different watts used for denture disinfection were effective in decreasing the number of microorganism in both mucosal swabs and denture swabs. ConclusionsIncreasing the watt intensity leads to decreasing the CFU. In mucosal swabs the decrease was non-significant. The adhesion of micro-organisms increases by time on mucosa and the denture base.

Comparative evaluation of tensile bond strength of a polyvinyl acetate-based resilient liner following various denture base surface pre-treatment methods and immersion in artificial salivary medium: An in vitro study.

Background and Aim:This study was formulated to evaluate and estimate the influence of various denture base resin surface pre-treatments (chemical and mechanical and combinations) upon tensile bond strength between a poly vinyl acetate-based denture liner and a denture base resin.Materials and Methods:A universal testing machine was used for determining the bond strength of the liner to surface pre-treated acrylic resin blocks. The data was analyzed by one-way analysis of variance and the t-test (α =.05).Results:This study infers that denture base surface pre-treatment can improve the adhesive tensile bond strength between the liner and denture base specimens. The results of this study infer that chemical, mechanical, and mechano-chemical pre-treatments will have different effects on the bond strength of the acrylic soft resilient liner to the denture base.Conclusion:Among the various methods of pre-treatment of denture base resins, it was inferred that the mechano-chemical pre-treatment method with air-borne particle abrasion followed by monomer application exhibited superior bond strength than other methods with the resilient liner. Hence, this method could be effectively used to improve bond strength between liner and denture base and thus could minimize delamination of liner from the denture base during function.

Evaluation of tensile bond strength of heat cure and autopolymerizing silicone-based resilient denture liners before and after thermocycling

To assess the effect of simulated mouth conditions reproduced with thermocycling on the tensile bond strength of two silicone based resilient denture liners with acrylic resin bases. Two silicone-based soft denture liners (Mollosil - Chairside autopolymerization and Molloplast B - Heat polymerization) were tested. For each liner, 30 specimens with a cross-sectional area of 10 Χ 10 mm and thickness 3 mm were processed between two acrylic blocks (Trevalon). Specimens were divided into a control group that was stored for 24 hours in water at 37°C and a test group that was thermocycled (2500 cycles) between baths of 5° and 55°C. Tensile bond strength (kg/cm²) was determined in a universal testing machine using crosshead speed of 5 mm/min. The student t-test was used to determine the significance of the difference in bond strength between the two liners. The mean tensile bond strength for control and thermocycled specimens of the two liners were: Mollosil (6.82 kg/cm² and 8.41 kg/cm²) and Molloplast-B (16.30 kg/cm² and 13.67 kg/cm²), respectively. Comparison of bond strength of control specimens with thermocycled specimens of the liners indicated a significant difference for both Mollosil (P=0.045) and Molloplast-B (P=0.027). Comparison between control specimens of both liners and thermocycled specimens of both liners indicated a highly significant difference (P<0.001). Heat polymerized resilient denture liner Molloplast-B had higher tensile bond strength than autopolymerizing liner Mollosil regardless of thermocycling. The bond strength of Mollosil increased after thermocycling while that of Molloplast-B decreased after thermocycling. Although heat-polymerized denture liners require more processing time than autopolymerizing liners, but they display much better adhesion properties to denture base resin and should thus be preferred when soft liner has to be used for a longer duration of time.

A Study to Evaluate and Compare the Shear Bond Strength of Resilient Liners with Heat Cure Denture Base Resins, with and without the Effect of Saliva: An in vitro Study

To evaluate and compare the shear bond strength of resilient liners with heat cure denture base resins in the presence or absence of saliva. Two commercially available heat polymerized acrylics and three commercially available denture liners were immersed in artificial saliva for 7 days and 14 days, respectively. A total of 180 (Acralyn-H, No.90 and Lucitone - 199, No.90) specimens were prepared. Total of 90 overlapping joint specimens were prepared, 45 of them using Acralyn H (AGroup) and rest 45 using Lucitone-199 (L-Group). The specimens were tested for flexural strength with a 3-point bending test on an Instron universal testing machine. The results were analyzed with a one-way analysis of variance (ANOVA). The mean difference in shear bond strength (SBS) at different time intervals was found to be statistically significant (p < 0.001). Lucitone-199 recorded a significantly higher mean SBS compared to Acralyn H (p < 0.001). Further, significant differences between GC and Densply, GC and Aswin liners, and between Dentsply and Aswin were noted (p < 0.001). Difference between baseline and 7 days time interval, as well as, between baseline and 14 days time interval with respect to the mean SBS of these materials were significant (p < 0.001). Also, the mean difference in SBS between 7 days time interval and 14 days time interval was statistically significant (p < 0.001). Among the three different liners, GC yielded a higher mean SBS compared to Aswin and Dentsply at all the three time intervals. The mean SBS recorded in Dentsply and Aswin was almost same at 14 days time interval, but at baseline and 7 days, it was higher in Aswin compared to Dentsply. Lucitone-199 recorded a higher mean SBS compared to Acralyn H. As the time interval increases, the mean SBS recorded in both the denture base materials decrease. Among the three different liners, GC yields a higher mean SBS compared to Aswin and Dentsply at all the three time intervals. The most common reason for failures of resilient linings in removable dentures is the separation of these linings from the denture base. Therefore, poor adhesive bond properties are one of the serious defects of the material in clinical practice.

Changes in roughness of denture base and reline materials by chemical disinfection or microwave irradiation: Surface roughness of denture base and reline materials

ObjectiveThe effect of disinfection by immersion in sodium perborate solution and microwave irradiation on surface roughness of one denture base resin (Lucitone 550 -L), 3 hard chairside reline resins (Tokuyama Rebase II-TR, New Truliner-NT, Ufi Gel hard-UH) and 3 resilient reline materials (Trusoft-T; Sofreliner-S, Dentusil-D) was evaluated. Material and methodsThirty specimens of each material were made and divided into 3 groups: Control - not disinfected; P - daily disinfection by immersing in sodium perborate solution (3.8%); MW - microwave disinfection (6 min/650 W). Roughness measurements were made after polymerization (baseline) and after 1, 3 and 28 days. Roughness differences relative to the baseline readings were analyzed by Student's t-test (P=0.05). ResultsAt baseline, Trusoft showed the highest (P<0.001) mean surface roughness (3.54 µm), and its surface roughness was significantly reduced after 28 days of disinfection by immersion in sodium perborate (P=0.013). Roughness measurements of material Trusoft were not performed after microwave disinfection due to the severe alterations on the surface. In the 3 groups evaluated, changes in roughness were significant for materials Ufi Gel hard (from 0.11 to 0.26 µm; P≤0.041) and New Truliner (0.19 to 0.76 µm; P≤0.019). The roughness of materials Lucitone 550 (0.37 µm), Tokuyama Rebase II (0.37 µm), Sofreliner (0.49 µm) and Dentusil (0.38 µm) remained unaffected (P>0.05). ConclusionsThe roughness of the hard reline materials Ufi Gel hard and New Truliner was adversely affected by microwave disinfection, immersion in water or in sodium perborate. Microwave disinfection caused severe alterations on the surface of the resilient liner Trusoft.

PENATALAKSANAAN RESESI GINGIVA DENGAN MENGGUNAKAN GINGIVA BUATAN: MANAGEMENT OF GINGIVAL RECESSION WITH THE USE OF ARTIFICIAL GINGIVA

The prevalence, extent, and severity of gingival recession increase with age and more prevalent in males. Recession is an exposure of the root surface and an apical shift of the gingival position. Recession may be localized in one tooth or a number of teeth, or it may be generalized through out the mouth. Gingival recession will be a problem when patient complained about esthetic, because teeth are seen longer . Gingival recession could happen either physiologic or pathologic. Physiologically, it usually increases with age. Pathologically, it is caused by fault tooth brushing technique, malposition, gingival inflammation, abnormal frenum attachment, and iatrogenic dentistry. Treatment of gingival recession result on esthetic problem and pain because of open dentine. Treatment could be done either with surgery or non surgery. Surgery technique can use flap non reposiotion. In this case report, patient had recession in man dible anterior region. She wanted to get esthetic appearance but she did not want to have surgery treatment. Artificial gingival was performend to cover the recession. Material of the artificial gingival is a soft liner ( chairside vinyl polysiloxane resilient denture liner ), because of good biocompatibility, nice colour and texture is invitiate real gingiva, although it has to take it off when eating and cleaning up . Main function of artificial gingival is esthetic function and cover the recession. In conclusion, after treatment showed good esthetic and patient. Beside treatment, we need to suggest patients to do plaque control and visit dentist at least twice a year.

Durability of peel bond of resilient denture liners to acrylic denture base resin

PurposeThe purpose of this study was to determine the durability of the peel bond of commercial resilient denture liners to a denture base resin using a thermal cycling test. MethodsEight commercial resilient denture liners (five silicone and three acrylic) were used in the study. The samples were exposed to thermal cycles between 5°C and 55°C for 1min for 0, 1,250, 2,500, 5,000 and 10,000 cycles. The test samples were placed under tension until failure in a materials testing machine using a crosshead speed of 20mm/min. The modes of debonding were characterized as tear, peel or snap. Statistical analysis was performed using one-way and two-way analysis of variance and Student–Newman–Keuls multiple comparison tests (α=.05). ResultsA significant difference was found between different resilient denture liners for peel bond strength at 0 cycles. No extreme influence on the peel bond strength was observed under any of the thermal cycles. The snap mode of debonding was observed in most samples of all materials for all cycles. ConclusionAll resilient denture liners tested had a sufficiently strong bond to the denture base resin. Within the limitations of this study, the results show that all of the materials were acceptable for clinical use, having met the accepted adequate bond strength for resilient denture liners of 0.45MPa.

Surface roughness of denture base and reline materials after disinfection by immersion in chlorhexidine or microwave irradiation

This study evaluated the effect of disinfection by immersion and microwave irradiation on the roughness of one denture base resin (Lucitone-L) and five relining materials, three hard (Tokuyama Rebase II-TR, New Truliner-NT, Ufigel Hard-UH) and two resilient (Trusoft-T, Sofreliner-S). Fifty specimens were made and divided into groups: CL2 specimens were brushed with 4% chlorhexidine (1 min), immersed in the same solution (10 min) and immersed in water (3 min); MW2 specimens were immersed in water and microwave irradiated (650W; 6 min); CL2 and MW2 specimens were disinfected twice; CL7 and MW7 specimens were submitted to seven cycles using chlorhexidine or microwave irradiation, respectively; W specimens were not disinfected and remained in water (37°C; 7 days). Results were statistically analysed (p = 0.05) and revealed that, at baseline, the highest mean value was observed for T (p < 0.001). Material NT showed increase in roughness after the first (p = 0.003), second (p = 0.001), seventh (p = 0.000) cycles of microwave disinfection and after 7 days of immersion in water (p = 0.033). Resilient liner S presented significant increase in roughness after the second cycle of disinfection with chlorhexidine (p = 0.003). Material T exhibited significantly decreased roughness in group W (p = 0.010), while microwaving produced severe alterations on its surface.