Effect of different disinfectants on the microhardness and roughness of acrylic resins for ocular prosthesis

Background: Ocular prosthesis materials should have specific properties for their indication and durability; therefore, it is important to investigate their physical behaviour when affected by several disinfectants. Objectives: This study evaluated the influence of different disinfecting solutions on the microhardness and surface roughness of acrylic resins for ocular prosthesis. Materials and Methods: Fifty samples simulating ocular prostheses were fabricated with N1 resin and colourless resin and divided (n = 10) according to the disinfectant used: neutral soap, Opti‐free, Efferdent, 1% hypochlorite (HYC) and 4% chlorhexidine (CHX). Samples were stored in saline solution at 37°C and disinfected during 120 days. Both microhardness and roughness were investigated before, after 60 days and 120 days of disinfection and storage. Microhardness was measured using a microhardner and the roughness with a roughness device. Results: N1 resin showed lower microhardness when compared with colourless resin (p < 0.05). HYC and CHX groups exhibited the highest change of microhardness and roughness values (p < 0.05). An increase in roughness and reduction in microhardness of ocular acrylic resins were observed after both periods of disinfection and storage (p < 0.05). Conclusion: Both disinfection/storage periods affected the microhardness and roughness values of the samples.     

Effect of reline material and denture base surface treatment on the impact strength of a denture base acrylic resin

doi:10.1111/j.1741‐2358.2009.00292.x
Effect of reline material and denture base surface treatment on the impact strength of a denture base acrylic resin Objective: In this study, the effect of relining and surface treatment on the impact strength (IS) of a heat‐polymerising denture base acrylic resin (Lucitone 550‐L) was evaluated. Materials and methods: Rectangular bars of L were made (60 × 6 × 2 mm) and relined (2 mm) with the relining resins Ufi Gel Hard (UH) and Tokuso Rebase Fast (TR). Specimens relined with L and intact L, TR and UH specimens were also made (60 × 6 × 4 mm), for comparison. Before relining, the L surface was left untreated or wetted with methyl methacrylate monomer and/or the bonding agents (BA) supplied by manufacturers of the reline resins. V‐notches were machined at the midpoint of the length of all specimens. The notches were made either across the width (Nw) or across the thickness of the specimens (Nth). The Charpy impact test was performed using a 0.5‐J pendulum, which had been specially designed and constructed. Data were analysed separately for each notch position using one‐way analysis of variance and Tukey honestly significant difference post‐hoc test (p = 0.05). Results: The IS of L was similar to that of L/L. For the Nw notch, treating the denture base L with TR BA and relining with TR reline material produced the highest IS. Conclusion: The IS of specimens made from heat polymerising acrylic resin Lucitone 550 was increased after relining using the hard chairside reline resin TR with its proprietary BA.     

Effect of thermal cycling and disinfection on colour stability of denture base acrylic resin

doi: 10.1111/j.1741‐2358.2012.00676.x Effect of thermal cycling and disinfection on colour stability of denture base acrylic resin Objectives: The purpose of this study was to investigate the effect of thermal cycling and disinfection on the colour change of denture base acrylic resin. Materials and Methods: Four different brands of acrylic resins were evaluated (Onda Cryl, QC 20, Classico and Lucitone). All brands were divided into four groups (n = 7) determined according to the disinfection procedure (microwave, Efferdent, 4% chlorhexidine or 1% hypochlorite). The treatments were conducted three times a week for 60 days. All specimens were thermal cycled between 5 and 55°C with 30‐s dwell times for 1000 cycles before and after disinfection. The specimens’ colour was measured with a spectrophotometer using the CIE L*a*b* system. The evaluations were conducted at baseline (B), after first thermal cycling (T₁), after disinfection (D) and after second thermal cycling (T₂). Colour differences (ΔE) were calculated between T₁ and B (T₁B), D and B (DB), and T₂ and B (T₂B) time‐points. Results: The samples submitted to disinfection by microwave and Efferdent exhibited the highest values of colour change. There were significant differences on colour change between the time‐points, except for the Lucitone acrylic resin. Conclusions: The thermal cycling and disinfection procedures significantly affected the colour stability of the samples. However, all values obtained for the acrylic resins are within acceptable clinical parameters.     

The combined effects of plasma and hydrogel coating on adhesion of Staphylococcus epidermidis and Staphylococcus aureus to polyurethane catheters

Abstract The adhesion of three Staphylococcus epidermidis and three S. aureus clinical isolates, to uncoated and hydrogel-coated polyurethane catheters was tested, following pretreatment of catheters with human plasma. Plasma significantly decreased the adhesion of S. epidermidis strains to uncoated polyurethane catheters, but had no significant effect on the adhesion to hydrogel-coated catheters. The influence of plasma on adhesion of S. aureus strains to catheters was strain dependent. Plasma significantly increased the adhesion of one strain (SA6) to uncoated catheters. For two other strains (SA3 and SA14) plasma produced no clear effect on their adhesion to uncoated catheters; adhesion values for each strain showed either a small but significant increase or a replicate-dependent increase or decrease. However, plasma significantly increased the adhesion of all S. aureus strains to hydrogel-coated polyurethane catheters. Overall, with the exception of one batch culture of S. epidermidis strain SE3 tested, attachment to plasma-treated hydrogel-coated catheters was statistically significantly lower, by up to 85%, than attachment to plasma-treated uncoated catheters for both S. epidermidis and S. aureus .     

Lack of biofilm contribution to bacterial colonisation in an experimental model of foreign body infection by Staphylococcus aureus and Staphylococcus epidermidis

The contribution of in vivo biofilm-forming potential of Staphylococcus aureus and Staphylococcus epidermidis was studied in an experimental model of foreign body infections. Increasing inocula (from 10(2) to 10(7) organisms) of ica-positive strains of S. aureus and S. epidermidis and their ica-negative isogenic mutants (the ica locus codes for a major polysaccharide component of biofilm) were injected into subcutaneously implanted tissue cages in guinea pigs. Surprisingly, bacterial counts and time-course of tissue cage infection by ica-positive strains of S. aureus or S. epidermidis were equivalent to those of their respective ica-negative mutants, in the locally infected fluids and on tissue-cage-inserted plastic coverslips.     

A method for the enumeration of bacterial adhesion to epithelial cells using image analysis

Abstract Computerised image analysis was utilised to enumerate the attachment of Staphylococcus epidermidis to HEp2 cell monolayers. A differential staining technique was employed such that individual staphylococcal cells stood out in sharp contrast against the uneven cell surface and granular contents of the epithelial cells. The primary image analysis operation involved subtracting an out-of-focus image from an in-focus image of the bacteria on the monolayer, thereby accentuating the bacterial image. Enumeration, using a particle counting routine, was rapid and reproducible, facilitating counting in excess of 700 bacteria per field at ×500 magnification. The computerised programme compared favourably with manual counting and would provide a rapid, objective and morphologically discriminatory method for evaluating bacterial attachment to various tissues.     

Effect of thermal cycling on microleakage between hard chairside relines and denture base acrylic resins

doi:10.1111/j.1741‐2358.2009.00332.x
Effect of thermal cycling on microleakage between hard chairside relines and denture base acrylic resins Objectives: Microleakage is a pre‐stage of debonding between hard chairside relines and denture base acrylic resins. Therefore, it is important to assess them with regard to the longevity of the relined denture. This study investigated the effect of thermal cycling on the microleakage at the interface of three hard chairside reline resins and three denture base resins. Material and methods: Rectangular bars (12 mm × 3 mm × 3 mm) of Lucitone 550, Acron MC and QC 20 were made and relined with Kooliner, Tokuyama Rebase Fast II and Ufi Gel Hard, Lucitone 550, Acron MC and QC 20 resins. Specimens were divided into one control and two test groups (n = 10). In specimens of the control group, the microleakage was performed after the reline procedure. In Test Group 1, the specimens were stored for 24 h in distilled water at room temperature and in Test Group 2; the specimens were thermal cycled from 5 to 55°C for 5000 cycles with a 30‐s dwell time. Subsequently, all specimens were immersed in 50% silver nitrate solutions for 24 h. All specimens were sectioned longitudinally into three fractions and the lateral sections were examined (n = 20). Silver nitrate stain penetration was examined under a stereoscopic lens with ×30 magnification, and the images were captured. Leica Qwin image analysis software was used to determine microleakage at the interface of the materials. Data were analysed using the Kruskal–Wallis test at a 95% level of significance. Results: For all cycles, there were no statistically significant differences between thermal cycled and non‐thermal cycled groups (p > 0.05). Conclusion: It can be concluded that thermal cycling had no effect on the microleakage.     

Effect of pre-processing methods on bond strength between acrylic resin teeth and acrylic denture base resin

doi: 10.1111/j.1741‐2358.2011.00480.x
Effect of pre‐processing methods on bond strength between acrylic resin teeth and acrylic denture base resin Objectives: This study evaluated the effects of various pre‐processing methods on the bond strength between resin and denture teeth. Backgrounds: Debonding of acrylic resin teeth from denture base material is a problem for patients wearing complete dentures. Materials and Methods: Four experimental groups (n = 30) were investigated by subjecting tooth–resin bonding to tensile loading. Specimens were prepared and tested according to the methods of the International Standards Organization (ISO 22112:2005) using a special assembly. Four pre‐processing surface treatments of teeth were applied: (i) ST₁, no treatment applied (control); (ii) ST₂, wax solvent (Dewaks, Faber Kimya & Ilaç, Turkey); (iii) ST₃, boiling water followed by conditioning with methyl methacrylate (MMA) monomer (Meliodent, Bayer Dental, Germany); (iv) ST₄, boiling water followed by wax solvent agent and finally MMA monomer application. Bond strength test was performed using a universal testing machine. Results: All the strength values of the test groups were within clinically acceptable limits. The lowest values were from the ST₁ group and the highest values were in the ST₄ group. Conclusions: Wax elimination methods affected bonding strength. Application of wax solvent and MMA monomer to the ridge lap surfaces of the teeth gave the best results. In clinical practice, this application procedure may decrease the bonding failure of denture teeth.     

Bond strength of denture teeth to acrylic resin: effect of thermocycling and polymerisation methods

Background: Failure of bonding between acrylic resin teeth and denture base material is a considerable problem for patients who wear complete dentures. Objective: The purpose of this study was to evaluate the bond strength between acrylic resins and resin denture teeth with different thermocycling and polymerisation methods. Materials and methods: Microwave‐polymerised (Onda‐Cryl), heat‐polymerised (Clássico) and autopolymerising (Jet) acrylic resins and resin denture tooth (Biotone) were used. The acrylic resins were polymerised according to the following: (A) microwave – fast cycle, Onda‐Cryl; (B) microwave – long cycle, Onda‐Cryl; (C) microwave – manufacturer’s cycle, Onda‐Cryl; (T) water bath – long cycle, Clássico; and (Q) bench polymerisation cycle, Jet. Twenty specimens were prepared for each polymerisation method. Ten were thermocycled, and 10 did not receive thermocycling. For the purpose of the study, a shear test was used. Data were analysed with the Kruskal–Wallis test and Dunn’s multiple comparisons test (p = 0.05). Results: Cycles B, C and T were similar (p > 0.05), and had statistically higher bonding values than cycles A and Q (p < 0.05) for the thermocycled and non‐thermocycled groups. For all cycles, there were no statistically significant differences between thermocycled and non‐thermocycled groups (p > 0.05), except for cycle Q (p = 0.0038). Conclusion: Thermocycling decreased the bond strength, but not significantly for microwave and heat‐polymerised cycles. Regarding the bond strength of denture teeth to acrylic resin, the fast microwave polymerisation cycle should be avoided when polymerising Onda‐Cryl acrylic resin. In addition, Jet acrylic resin is not adequate for use in denture repair.     

Influence of artificial accelerated ageing on the colour stability of paints used for ocular prosthesis iris painting

doi: 10.1111/j.1741‐2358.2010.00473.x
Influence of artificial accelerated ageing on the colour stability of paints used for ocular prosthesis iris painting Objectives: To evaluate the colour stability of paints used for ocular prosthesis iris painting submitted for accelerated artificial ageing (AAA). Materials and methods: Forty specimens of acrylic resin for sclera (16 × 2 mm) were made and separated into eight groups (n = 10) according to the type of paint (gouache, GP; oil, OP; acrylic AP; and composite resin for characterisation, CR) and the colours used (blue/brown). After drying (72 h), a new layer of colourless acrylic resin was applied and the initial colour readout was performed (Spectrophotometer PCB 6807). New colour readouts were performed after AAA, and ΔE was calculated. Results: Statistical analysis (two‐way anova –Bonferroni, p < 0.05) demonstrated that the brown colour showed lower ΔE means in comparison with the blue colour, with statistically significant difference for AP only. Blue colour showed no statistically significant difference with regard to the type of paint used. Brown AP showed lower ΔE than the other groups, with significant difference for OP and GP. GP showed greater alteration in ΔE for the brown colour, being statistically similar only to OP. Conclusions: Only the AP group for brown pigment shows clinically acceptable values for colour stability after AAA.     

Effect of the physical properties of acrylic resin of overnight immersion in sodium hypochlorite solution

doi:10.1111/j.1741‐2358.2009.00336.x
Effect of the physical properties of acrylic resin of overnight immersion in sodium hypochlorite solution Objectives: This study evaluated colour stability, surface roughness and flexural strength of microwave‐polymerised acrylic resin after overnight immersion in sodium hypochlorite, simulating 180 days use. Materials and methods: Forty disc‐shaped (15 mm × 4 mm) and 40 rectangular specimens (65 mm × 10 mm × 3 mm) were prepared from microwave‐polymerised acrylic resin. The specimens were immersed in 0.5, 1% sodium hypochlorite, Clorox/Calgon and distilled water. Colour measurements (ΔE) were determined by a portable colorimeter. A surface analyser was used to measure roughness (μm). The flexural strength (MPa) was measured using a three‐point bending test in a universal testing machine. Data were evaluated by one‐way anova , followed by Student–Newman–Keuls test (α = 0.05). Results: Statistical analysis found significantly higher colour changes (SNK, p < 0.001) for the 1% sodium hypochlorite, but mean ΔE value quantified by National Bureau of Standards was classified as slight. When comparing the surface roughness, no statistical significance was found among the solutions (anova , p = 0.637). The 1% sodium hypochlorite presented significantly lower flexural strength compared with the control group (SNK, p = 0.034). Conclusion: It was concluded that immersion in 1% sodium hypochlorite solutions for 8 h does influence the colour stability and flexural strength of microwave‐polymerised acrylic resin, during the simulated period of 180 days.     

Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin

doi:10.1111/j.1741‐2358.2009.00333.x
Effect of microwave treatment on the shear bond strength of different types of commercial teeth to acrylic resin Objective: The purpose of this study was to verify the effect of microwave treatment on the shear bond strength of commercial types of teeth to acrylic resin, when the glossy ridge laps were unmodified (groups 1 and 5), bur abraded (groups 2 and 6), bur grooved (groups 3 and 7) or etched by monomer (groups 4 and 8). Background: Controversial findings have shown that mechanical or chemical changes in ridge‐lap surface of the tooth increase or decrease the bond strength between tooth and acrylic resin, and the microwave disinfection may cause different changes on this bond strength. Materials and methods: Eighty specimens (n = 10) were made with the acrylic resin bonded to tooth glossy ridge lap, polymerised in water at 74°C for 9 h, and deflasked after flask cooling. Specimens of the groups 5, 6, 7 and 8 were individually immersed in 150 ml of water and submitted to microwave treatment in an oven at 650 W for 3 min. Control specimens (groups 1, 2, 3 and 4) were not microwave treated. Shear bond strength test was performed in an Instron machine with a cross‐speed of 1 mm/min. Collected data were submitted to anova and Tukey’s test (α = 0.05). Results: Microwave treatment decreased the shear bond strength values of the tooth/resin bond. In the microwaved and non‐microwaved procedures, mechanical retention improved the shear bond strength when compared with the control and monomer treatments. Conclusion: Shear bond strength of the tooth/resin bond was influenced by the microwave treatment and different commercial teeth association, and was lower for the Biotone tooth.     

Effect of disinfection and storage on the flexural strength of ocular prosthetic acrylic resins

doi: 10.1111/j.1741‐2358.2011.00570.x Effect of disinfection and storage on the flexural strength of ocular prosthetic acrylic resins Objective: To evaluate the influence of chemical disinfection and storage duration on the flexural strength of acrylic resins commonly used to make ocular prostheses. Methods: A total of 260 samples were manufactured with N1 resin and colourless resin. Both resins were thermopolymerised using a microwave oven. Samples were stored and periodically disinfected and were divided into groups: control (no disinfection) (I), neutral soap (II), Opti‐free (III), Efferdent (IV), 1% hypochlorite (V) or 4% chlorhexidine (VI). The flexural strength was measured before and after 60 and 120 days of storage. Data were analysed by anova and Tukey test (0.05). Results: The flexural strength of the N1 resin was higher than that for the colourless resin. There was a significant difference in the flexural strength before and after 60 and 120 days of storage with disinfection, regardless of the resin and disinfectant. Group I in the initial period exhibited greater flexural strength, with significant difference only in group VI after 120 days. Conclusion: It can be concluded that the flexural strength only changed after 120 days of storage for samples disinfected with chlorhexidine. However, all flexural strength values obtained herein were acceptable clinical limits for the acrylic resins.     

Role of hypermutability on bacterial fitness and emergence of resistance in experimental osteomyelitis due to Staphylococcus aureus

This study was designed to investigate the role of hypermutability of Staphylococcus aureus on bacterial fitness and antibiotic resistance in a model of chronic bone infection. An isogenic pair of strains, S. aureus RN4220 and its mutator counterpart inactivated in the mutL gene were used in a rat model of osteomyelitis of the tibia. The effect of the mutator phenotype in the emergence of antibiotic resistance was assessed in rats infected by each strain separately and treated with rifampicin for 5 days. No difference between the two strains was found in bacterial growth in vitro and in bacterial survival in the animal model, indicating no fitness defect in the mutator strain. In competition studies performed in rats coinfected with the two strains at a same ratio and sacrificed at different times from day 3 to day 42 postinoculation, the mutator strain was clearly disadvantaged because it was found in all rats and at all study times at lower counts (P<0.05 from day 14 to day 42). Two of the 16 rats infected by the mutator strain and none of the 14 rats infected by the wild-type strain had acquired rifampicin-resistant mutants (P=0.4). Data suggest that the S. aureus mutator phenotype was associated with a decreased bacterial fitness in vivo and did not confer significant advantage in the acquisition of antibiotic resistance in a model of chronic bone infection.     

Effect of the addition of silanated silica on the mechanical properties of microwave heat-cured acrylic resin

doi: 10.1111/j.1741‐2358.2011.00604.x
Effect of the addition of silanated silica on the mechanical properties of microwave heat‐cured acrylic resin Objectives: The purpose of this study was to evaluate fthe flexural strength and Vickers hardness of a microwave energy heat‐cured acrylic resin by adding different concentrations of silane surface‐treated nanoparticle silica. Methods: Acrylic resin specimens with dimensions of 65 × 10 × 2.5 mm were formed and divided into five experimental groups (n = 10) according to the silica concentration added to the acrylic resin mass (weight %) prior to polymerisation : G1, without silica; G2, 0.1% silica; G3, 0.5% silica; G4, 1.0% silica; and G5, 5.0% silica. The specimens were submitted to a three‐point flexural strength test and to the Vickers hardness test (HVN). The data obtained were statistically analysed by anova and the Tukey test (α = 0.05). Results: Regarding flexural strength, G5 differed from the other experimental groups (G1, G2, G3 and G4) presenting the lowest mean, while G4 presented a significantly higher mean, with the exception of group G3. Regarding Vickers hardness, a decrease in values was observed, in which G1 presented the highest hardness compared with the other experimental groups. Conclusion: Incorporating surface‐treated silica resulted in direct benefits in the flexural strength of the acrylic resin activated by microwave energy; however, similar results were not achieved for hardness.     

Effect of monomer treatment and polymerisation methods on the bond strength of resin teeth to denture base material

Background: The fracture between acrylic denture base material and artificial teeth is a common clinical occurrence in dental prosthodontic practice. Objective: To evaluate the bond strength between acrylic resins and resin denture teeth when submitted by two protocols of monomer liquid application on the tooth surface and using different polymerisation methods. Material and methods: Microwave‐polymerised (Onda‐Cryl), heat‐polymerised (Clássico) and autopolymerising (Jet) acrylic resins and a brand of resin denture teeth (Biotone) were used. The acrylic resins were polymerised according to the cycles: (A) microwave – fast cycle, Onda‐Cryl; (B) microwave – long cycle, Onda‐Cryl; (C) microwave – manufacturer’s cycle, Onda‐Cryl; (T) water bath – long cycle, Clássico and (Q) bench polymerisation cycle, Jet. Thirty specimens were prepared for each polymerisation method; 10 were packed with acrylic resin after 60 s of monomer liquid application on the tooth surface, 10 after 180 s and 10 without any monomer liquid application. For the purpose of the study, a shear test was used. anova and Tukey tests were performed to identify significant differences (α = 0.05). Results: The highest bond strength values were found for monomer surface treatments, regardless of the polymerisation cycles. The highest significant values were found for cycles B (15.4 ± 1.8 MPa), C (11.9 ± 4.9 MPa) and T (15.4 ± 2.6 MPa) for non‐treated and 60 s methylmethacrylate treated groups. Comparing the monomer liquid treatment, they did not differ significantly (p > 0.05), except for cycle A (p < 0.05). Conclusion: Chemical treatment using monomer on the tooth surface prior to the acrylic resin packing improved the bond strength between resin denture tooth and acrylic resin, regardless of monomer liquid treatment protocols. The microwavable resin, polymerised by fast cycle and autopolymerising resin should be avoided for processing denture and denture repairs, respectively.     

Effect of chlorhexidine and benzalkonium chloride on bacterial biofilm formation

AIM: To study the effect of antiseptics on bacterial biofilm formation. METHODS AND RESULTS: Biofilm formation and planktonic growth were tested in microtiter plates in the presence of antiseptics. For Escherichia coli G1473 in the presence of chlorhexidine or benzalkonium chloride, for Klebsiella pneumoniae CF504 in the presence of chlorhexidine and for Pseudomonas aeruginosa PAO1 in the presence of benzalkonium chloride, biofilm development and planktonic growth were affected at the same concentrations of antiseptics. For PAO1 in the presence of chlorhexidine and CF504 in the presence of benzalkonium chloride, planktonic growth was significantly inhibited by a fourfold lower antiseptic concentration than biofilm development. For Staphylococcus epidermidis CIP53124 in the presence of antiseptics at the minimal inhibitory concentration (MIC), a total inhibition of biofilm formation was observed. For Staph. epidermidis exposed to chlorhexidine at 1/2, 1/4 and 1/8 MIC, or to benzalkonium chloride at 1/8, 1/16 or 1/32 MIC, biofilm formation was increased from 11.4% to 22.5% without any significant effect onto planktonic growth. CONCLUSIONS: Chlorhexidine and benzalkonium chloride inhibited biofilm formation of different bacterial species but were able to induce biofilm development for the Staph. epidermidis CIP53124 strain at sub-MICs. SIGNIFICANCE AND IMPACT OF THE STUDY: Sublethal exposure to cationic antiseptics may contribute to the persistence of staphylococci through biofilm induction.     

Effect of ultrafine-grained titanium surfaces on adhesion of bacteria

The influence of the ultrafine crystallinity of commercial purity grade 2 (as-received) titanium and titanium modified by equal channel angular pressing (modified titanium) on bacterial attachment was studied. A topographic profile analysis of the surface of the modified titanium revealed a complex morphology of the surface. Its prominent micro- and nano-scale features were 100–200-nm-scale undulations with 10–15 μm spacing. The undulating surfaces were nano-smooth, with height variations not exceeding 5–10 nm. These surface topography characteristics were distinctly different from those of the as-received samples, where broad valleys (up to 40–60 μm) were detected, whose inner surfaces exhibited asperities approximately 100 nm in height spaced at 1–2 μm. It was found that each of the three bacteria strains used in this study as adsorbates, viz. Staphylococcus aureus CIP 68.5, Pseudomonas aeruginosa ATCC 9025 and Escherichia coli K12, responded differently to the two types of titanium surfaces. Extreme grain refinement by ECAP resulted in substantially increased numbers of cells attached to the surface compared to as-received titanium. This enhanced degree of attachment was accompanied with an increased level of extracellular polymeric substances (EPS) production by the bacteria. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effect of repeated cycles of chemical disinfection on the roughness and hardness of hard reline acrylic resins

doi:10.1111/j.1741‐2358.2009.00282.x
Effect of repeated cycles of chemical disinfection on the roughness and hardness of hard reline acrylic resins Objective: The aim of this study was to assess the effect of repeated cycles of five chemical disinfectant solutions on the roughness and hardness of three hard chairside reliners. Methods: A total of 180 circular specimens (30 mm × 6 mm) were fabricated using three hard chairside reliners (Jet; n = 60, Kooliner; n = 60, Tokuyama Rebase II Fast; n = 60), which were immersed in deionised water (control), and five disinfectant solutions (1%, 2%, 5.25% sodium hypochlorite; 2% glutaraldehyde; 4% chlorhexidine gluconate). They were tested for Knoop hardness (KHN) and surface roughness (μm), before and after 30 simulated disinfecting cycles. Data was analysed by the factorial scheme (6 × 2), two‐way analysis of variance (anova ), followed by Tukey’s test. Results: For Jet (from 18.74 to 13.86 KHN), Kooliner (from 14.09 to 8.72 KHN), Tokuyama (from 12.57 to 8.28 KHN) a significant decrease in hardness was observed irrespective of the solution used on all materials. For Jet (from 0.09 to 0.11 μm) there was a statistically significant increase in roughness. Kooliner (from 0.36 to 0.26 μm) presented a statistically significant decrease in roughness and Tokuyama (from 0.15 to 0.11 μm) presented no statistically significant difference after 30 days. Conclusions: This study showed that all disinfectant solutions promoted a statistically significant decrease in hardness, whereas with roughness, the materials tested showed a statistically significant increase, except for Tokuyama. Although statistically significant values were registered, these results could not be considered clinically significant.