The effect of cavity disinfectants on the micro-shear bond strength of dentin adhesives

Evaluation of different decontamination procedures on bond strength to sound and caries affected dentin using "no-wait" universal adhesive

BACKGROUND

Current study aimed to evaluate the effect of different decontamination procedures on micro-shear bond strength (μSBS) of sound (SoD) and caries-affected dentin (CAD) of two universal adhesives after blood-saliva contamination.

METHODS

One hundred and eighty bovine anterior teeth were prepared and allocated into the respective groups according to tested dentin substrates [SoD, CAD], universal adhesives [Clearfil Bond Universal Quick (UBQ), All-Bond-Universal (ABU)], adhesive contamination stage [none, contamination before and after adhesives light-curing], and according to decontamination procedures [no decontamination, water rinsing, adhesive rebond, Ethylenediaminetetraacetic acid (ETDA) and chlorhexidine (CHX) application]. Universal adhesives were applied according to manufacturer instructions in self-etch (SE) bonding mode. Four composite microrods were built for each tooth. Specimens were kept in distilled water for 24 hours at 37°C before testing μSBS. Four-way ANOVA and Tukey HSD tests were used for data analysis.

RESULTS

A statistically significant difference between contamination stages of both universal adhesives at different decontamination procedures for SoD and CAD. Highest μSBS was recorded for UBQ control group at SoD, while the least was recorded for light-cured ABU upon water rinsing decontamination procedure of CAD.

CONCLUSIONS

Proper cavity isolation is mandatory to avoid possible contamination which can dramatically affect μSBS. CHX is a potent cavity decontaminant that can restore different dentin substrates bond strength. EDTA presents a promising substitute. UBQ adhesive showed better bonding performance than ABU to both dentin substrates. Application of regular cavity decontamination approaches is highly advised in daily practice to avoid possible detrimental effect of accidental cavity contamination.

Effect of chlorhexidine and benzalkonium chloride on the long-term push-out bond strength of fiber posts

Background and Aim

Fiber posts are widely used in endodontically treated teeth with extensive loss of coronal structure. The purpose of this study was to investigate immediate and the long-term effects of chlorhexidine (CHX) and benzalkonium chloride (BAC) application, on the push-out bond strength of fiber posts.

Material and Methods

Sixty mandibular premolars were decoronated, and root canal treatment was performed. After post space preparation, the specimens were divided into three groups according to the post space-surface pretreatment (n = 20); no surface treatment (control group-Group 1), 2% CHX application (Group 2), and 1% BAC application (Group 3). A self-curing adhesive cement and an etch and rinse adhesive were used for the cementation of posts. Three sections (one cervical, one middle, and one apical) of 1 mm thickness were prepared from each specimen. A push-out test was performed immediately on the half of the specimen sections (n = 10). The other half of the specimen sections were subjected to 20.000 thermal cycles before applying the push-out test (n = 10). The failure mode of each specimen was observed under a stereomicroscope at ×40 magnification.

Results

The data were analyzed by one-way analysis of variance (ANOVA), Tukey Honestly significant difference (HSD), and Tamhane tests (P = 0.05). The cervical thirds displayed the highest, and the apical thirds showed the lowest values in all groups (P < 0.05), except the control-aged group (P = 0.554). The aged control groups' values were found to be significantly lower than the aged CHX and BAC groups (P < 0.001). Aging significantly reduced the bond strength values of specimens in control groups (P < 0.001). However, aging did not significantly affect the push-out bond strength values of CHX and BAC groups (P > 0.050). The failure types were adhesive between the post and cement (type 1) in all groups, except control-aged group (type 2).

Conclusion

The application of 2% chlorhexidine or 1% BAC may be an essential step that can be taken to preserve the bond strength of fiber posts.

Effect of Antibacterial Agents on Dentin Bond Strength of Bioactive Restorative Materials

Treating dentin surfaces with antibacterial agents prior to bonding bioactive restorations might affect their mechanical properties. In this study, we evaluated the effect of silver diamine fluoride (SDF) and chlorhexidine (CHX) on the shear bond strength (SBS) of bioactive restorative materials. Dentin discs were treated with SDF for 60 s or CHX for 20 s and bonded with four restorative materials, namely Activa Bioactive Restorative (AB), Beautifil II (BF), Fuji II LC (FJ), and Surefil One (SO). Control discs were bonded without treatment (n = 10). SBS was determined using a universal testing machine, and a scanning electron microscope (SEM) was used for the evaluation of the failure mode and the cross-sectional examination of adhesive interfaces. The SBS of each material between different treatments and of the different materials within each treatment were compared via a Kruskal-Wallis test. The SBS of AB and BF was significantly higher than that of FJ and SO in the control and CHX groups (p < 0.01). In the latter, SBS was higher in FJ than SO (p < 0.01). SO had a higher value with SDF compared to CHX (p = 0.01). The SBS of SDF-treated FJ was higher than that of the control (p < 0.01). SEM showed a more homogenous and improved interface of FJ and SO with SDF. Neither CHX nor SDF compromised the dentin bonding of bioactive restorative materials.

Effect of Different Cavity Disinfectants on Adhesion to Dentin of Permanent Teeth

After the elimination of dental caries lesions, some microorganisms may remain viable in the tooth structure. Thus, cavity disinfection is an important procedure. The aim of this study was to evaluate the effect of cavity disinfectants on the adhesion to dentin of permanent teeth. Sixty molars were ground flat and randomly assigned to six groups: control; chlorhexidine; Aloe vera; glutaraldehyde; EDTA; ethanol. Cavity disinfectants were applied, rinsed, and air-dried. The restorations were performed with the aid of polyethylene tubes. Shear bond strength, work to detachment, and shear modulus were evaluated. All data were statistically analyzed and the level of significance was set at 5%. The control group showed the lowest shear bond strength (8.34 ± 2.68 MPa). Aloe vera showed the lowest work to debonding (2284 J/m²) while chlorhexidine showed the highest (9347 J/m²). Regarding the shear modulus, ethanol, chlorhexidine, and EDTA presented similar values to the control group (216.11 kPa), and glutaraldehyde and Aloe vera presented values twice as high. The use of chlorhexidine, ethanol, EDTA, glutaraldehyde, and Aloe vera did not impair the adhesion established between the dentin of permanent teeth and composite resin. Even though there is a need for clinical studies to support these findings, all disinfectants seem to be good choices as pretreatment agents.

Effect of Dentin-Disinfection Chemicals on Shear Bond Strength and Microhardness of Resin-Infiltrated Human Dentin in Different Adhesive Protocols

Background and Objectives: Bacteria and its remnants beneath the restorations predispose the tooth to secondary caries and pulpal pathology. Hence, various chemical antibacterial agents are suggested to disinfect the prepared tooth structure before the definitive restorative procedure. This study aimed to investigate the effects of chemical disinfectant solutions on the micro-shear bond strength (µSBS) and microhardness of total-etch and self-etch resin-infiltrated human dentin. Materials and Methods: 100 caries-free intact permanent third molar teeth were vertically sectioned into the buccal and lingual half. All these specimens were mounted on acrylic resin and underlying dentin surfaces were exposed by grinding. Samples were randomly divided into five groups [n = 20] following total-etch and self-etch adhesive protocol. Teeth samples were divided according to surface treatment, as Group I (Control-CNT), Group II (2% chlorhexidine-CHX), Group III (5.25% sodium hypochlorite-NaOCl), Group IV (17% ethylenediaminetetraacetate acid—EDTA) and Group V (10% povidone iodine-PVI). A randomly selected 10 samples from each subgroup were used for µSBS and microhardness tests. After surface treatment and bonding procedure, nono-hybrid composite cylinders with a 3-mm diameter and 2-mm height were directly cured over the dentin substrate. The samples for µSBS were subjected to 5000 thermocycles and tested using a universal testing machine. Microhardness was assessed using a micro-indenter instrument, data were statistically analyzed using a one-way analysis of variance and Tukey HSD tests at p < 0.05. Results: Amongst the chemical disinfectant assessed, 2% CHX did not affect µSBS and produced a marginal reduction in dentin microhardness compared to the control group. The 5.25% NaOCl and 17% EDTA significantly compromised the microhardness of the dentin substrate. Meanwhile, 10% PVI surface treatment resulted in a substantial reduction in µSBS between composite and dentin. Conclusions: CHX with preservation of bonding to dentin and insignificant negative effect on dentin microhardness is a safe option for tooth disinfection.

Influence of 2% Chlorhexidine on the Bond Strength of Three Adhesive Systems on Primary Molars: An In Vitro Study

The hydrolysis of the collagen matrix by metalloproteinases (MMPs) is one of the paradigms that currently arouses most interest due to its close relationship with a decrease in bond strength (BS) and consequent restoration failure. Chlorhexidine 2% has demonstrated its ability to inhibit MMPs’ activity in the permanent dentition, improving the duration of resin–dentine, but there are few studies on deciduous dentition and its possible repercussions. Aim: To determine the influence of 2% chlorhexidine digluconate (CHX) as a dentine pretreatment on the BS of three adhesive systems on primary molars. Methods: 128 primary extracted molars were assigned to eight groups at random. BS in vitro was recorded by micropush-out test, and analyzed by two-way ANOVA. Results: BS values oscillated from 15.01 MPa to 20.41 MPa. There was no statistically relevant variation between the BS total mean of those adhesive groups that had received CHX pretreatment versus those that did not. Adper Prompt L-Pop was the self-etching adhesive with the best BS. Adper Scotchbond 1XT was the total-etch adhesive with the best BS values. Conclusions: Application of 2% chlorhexidine for 60 s as dentine pretreatment did not affect the immediate BS of several adhesive systems used in primary dentition.

Effect of Cavity Disinfectants on Adhesion to Primary Teeth-A Systematic Review

Some authors have been proposing the use of cavity disinfectants in order to reduce, or even eliminate, the effect of the microorganisms present in a dental cavity before a restoration is placed. The aim of this study was to evaluate the effect of different cavity disinfectants on bond strength and clinical success of composite and glass ionomer restorations on primary teeth. The research was conducted using Cochrane Library, PubMed/MEDLINE, SCOPUS, and Web of Science for articles published up to February 2021. The search was performed according to the PICO strategy. The evaluation of the methodological quality of each in vitro study was assessed using the CONSORT checklist for reporting in vitro studies on dental materials. Sixteen in vitro studies and one in situ study fulfilled the inclusion criteria and were analyzed. Chlorhexidine was the most studied cavity disinfectant, and its use does not compromise dentin bonding. Sodium hypochlorite is a promising alternative, but more research on its use is required to clearly state that it can safely be used as a cavity disinfectant for primary teeth. Although other disinfectants were studied, there is a low-level evidence attesting their effects on adhesion, therefore their use should be avoided.

Effect of Cavity Disinfectants on Dentin Bond Strength and Clinical Success of Composite Restorations-A Systematic Review of In Vitro, In Situ and Clinical Studies

Cavity disinfection becomes an important step before a dental restorative procedure. The disinfection can be obtained cleaning the dental cavity with antimicrobial agents before the use of adhesive systems. The aim of this study was to conduct a systematic review on the effect of different cavity disinfectants on restorations’ adhesion and clinical success. A search was carried out through the Cochrane Library, PubMed, and Web of Science. In vitro and in situ studies reporting results on dentin bond strength tests, and clinical studies published until August 2020, in English, Spanish and Portuguese were included. The methodological quality assessment of the clinical studies was carried out using the Revised Cochrane risk-of-bias tool. Chlorhexidine could preserve adhesion to dentin. EDTA and ethanol had positive results that should be further confirmed. Given the significant lack of scientific evidence, the use of lasers, fluoridated agents, sodium hypochlorite, or other products as cavity disinfectants should be avoided. Chlorhexidine is a safe option for cavity disinfection with adequate preservation of adhesion to dentin. Moreover, future researches should be focused on the efficacy of these disinfectants against cariogenic bacteria and their best application methods.

The effects of cavity disinfection on the nanoleakage of compomer restorations: an in vitro study

Purpose:

Cavity disinfection, in addition to routine caries removal methods, is recommended to eliminate the microorganisms. The aim of this study was to compare the effect of various systems Er,Cr:YSGG lasers, diode lasers and FotoSan and agents Corsodyl; Cervitec and Cervitec Plus and Fluor Protector—on the nanoleakage of compomer restorations when used for cavity disinfection.

Materials and methods:

A total of 40 intact human deciduous molar teeth containing Black V cavities (3×2×1.5 mm) on the buccal and lingual surfaces parallel to the cementoenamel junction were randomly divided into 8 groups according to the cavity disinfection methods. The antibacterial agents and systems were applied according to the manufacturer’s instructions. Restorations were completed using a compomer. The restored teeth were then subjected to thermocycling for 500 cycles in a water bath at 5°C and 55°C with a dwell time of 30 seconds. After the thermocycling procedures, 1-mm sticks were obtained from the center of each cavity to prepare for the nanoleakage test. After the teeth were sectioned, they were immersed in 50 wt % ammoniacal silver nitrate solution for 24 hours and dipped in photo-developing solutions for 8 hours with fluorescent light irradiation. The samples were examined under a scanning electron microscope (SEM). The non-parametric Kruskal-Wallis and Mann-Whitney U test (p<0.05) were applied.

Results:

The Er,Cr:YSGG laser group showed significantly less nanoleakage than all of the tested groups (p<0.01). The diode laser, Fluor protector and FotoSan groups showed similar nanoleakage to that of the control group (p>0.05). The Corsodyl (p<0.01) and Cervitec (p<0.001) groups showed significantly higher nanoleakage than the control group.

Conclusion:

Er,Cr:YSGG laser irradiation which showed lower nanoleakage scores from either control or tested groups can be recommended for cavity disinfection Additionally, a diode laser and FotoSan, which have antibacterial effects and no negative effect on leakage, can be used for cavity disinfection.

Effect of 0.12% chlorhexidine and zinc nanoparticles on the microshear bond strength of dentin with a fifth-generation adhesive

Objective:

In this study, we compared the effects of 0.12% chlorhexidine (CHX) and nano zinc oxide (NZO) on the microshear bond strength of dentin with a fifth-generation adhesive after acid etching.

Materials and Methods:

Forty molar teeth were randomly divided into four main groups based on dentin surface treatment technique (a) control (single bond 2); (b) NZO; (c) CHX; and (d) NZO + CHX. In each group, half of the samples underwent thermocycling, with no thermocycling in the other half. Then, failure mode was evaluated under a stereomicroscope. Statistical analysis was performed using t-test, two-way ANOVA, and Chi-squared test.

Results:

The mean microshear bond strength of the groups without thermocycling was more than that of the groups with thermocycling, but there were no statistically significant differences between the groups with and without thermocycling in pair-wise comparisons.

Conclusion:

Pretreatment with NZO and CHX separately and simultaneously had no effect on the microshear bond strength of a fifth-generation adhesive.

The innovative applications of therapeutic nanostructures in dentistry

Nanotechnology has paved multiple ways in preventing, reversing or restoring dental caries which is one of the major health care problems. Nanotechnology aided in processing variety of nanomaterials with innovative dental applications. Some showed antimicrobial effect helping in the preventive stage. Others have remineralizing potential intercepting early lesion progression as nanosized calcium phosphate, carbonate hydroxyapatite nanocrystals, nanoamorphous calcium phosphate and nanoparticulate bioactive glass particularly with provision of self-assembles protein that furnish essential role in biomimetic repair. The unique size of nanomaterials makes them fascinating carriers for dental products. Thus, it is recentlyclaimedthat fortifying the adhesives with nanomaterials that possess biological meritsdoes not only enhance the mechanical and physical properties of the adhesives, but also help to attain and maintain a durable adhesive joint and enhanced longevity. Accordingly, this review will focus on the current status and the future implications of nanotechnology in preventive and adhesive dentistry.

Effect of Bioactive Primers on Bacterial-Induced Secondary Caries at the Tooth-Resin Interface

Secondary caries at the tooth-resin interface is the primary reason for replacement of resin composite restorations. The tooth-resin interface is formed by the interlocking of resin material with hydroxyapatite crystals in enamel and collagen mesh structure in dentin. Efforts to strengthen the tooth-resin interface have identified chemical agents with dentin collagen cross-linking potential and antimicrobial activities. The purpose of the present study was to assess protective effects of bioactive primer against secondary caries development around enamel and dentin margins of class V restorations, using an in vitro bacterial caries model. Class V composite restorations were prepared on 60 bovine teeth (n=15) with pretreatment of the cavity walls with control buffer solution, an enriched fraction of grape seed extract (e-GSE), 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide/N-hydroxysuccinimide, or chlorhexidine digluconate. After incubating specimens in a bacterial model with Streptococcus mutans for four days, dentin and enamel were assessed by fluorescence microscopy. Results revealed that only the naturally occurring product, e-GSE, significantly inhibited the development of secondary caries immediately adjacent to the dentin-resin interface, as indicated by the caries inhibition zone. No inhibitory effects were observed in enamel margins. The results suggest that the incorporation of e-GSE into components of the adhesive system may inhibit secondary caries and potentially contribute to the protection of highly vulnerable dentin-resin margins.

Effect of Chlorhexidine Application Protocol on Durability of Marginal Seal of Class V Restorations

OBJECTIVES

This study aimed to evaluate the effect of chlorhexidine (CHX) application protocol on durability of marginal seal of class V composite restorations.

MATERIALS AND METHODS

Class V cavities (4×2×1.5mm) were prepared in the buccal surfaces of 160 human third molars. The teeth were randomly divided into five groups (n=32) of (G1) CHX+rinse+etching, (G2) CHX+etching, (G3) etching+CHX+rinse, (G4) etching+ CHX, and (G5) etching alone as the control group. Adper Single Bond 2 was applied as an etch and rinse (E & R) bonding system. Cavities were filled with Z350 composite. Half of the teeth in each group were stored in distilled water for 24 hours and the other half were thermocycled (10,000 cycles, 5-55°C). For dye penetration test, the teeth were sectioned buccolingually and assessed at the enamel and dentin margins under a stereomicroscope at ×20 magnification. The Kruskal-Wallis, Dunn and Mann-Whitney tests were used for statistical analyses.

RESULTS

There was no significant difference in immediate microleakage among the groups at the enamel and dentin margins (P= 0.894). After thermocycling, there was significantly less microleakage in G4 than the control group at dentin margin. There were significant differences in microleakage between G4 and G1(P=0.002), G4 and G2 (P=0.001) and G4 and G5 (P= 0.001) at dentin margin.

CONCLUSIONS

Application of CHX after etching without rinsing is effective to decrease microleakage. However, it has no effect if applied before etching in use of this particular type of E & R adhesive after thermocycling.

Assessment of post-contamination treatments affecting different bonding stages to dentin

Objectives:

To assess the effect of cleansing treatments following saliva and blood contamination at different bonding stages to dentin.

Materials and Methods:

Labial surfaces of 168 permanent maxillary central incisors were ground flat exposing superficial dentin. Specimens were divided into: uncontaminated control (A), contamination after etching (B), contamination after adhesive application (C), contamination after adhesive polymerization (D). Groups were further subdivided according to cleansing treatments into: rinsing (B1, C1, D1), re-etching (B2, D3), sodium hypochlorite application (B3), ethyl alcohol application (C2), acetone application (C3), rinsing and rebonding (D2), re-etching and rebonding (D4). Composite microcylinders were bonded to treated substrates and shear loaded micro-shear bond strength (μSBS) until failure and treated surfaces were examined with scanning electron microscope. Debonded surfaces were classified as adhesive, cohesive or mixed failure. The data were analyzed using one-way ANOVA and Tukey's post hoc test.

Results:

The μSBS values were ranked as follow; Group B: A > B3 > B2 > B1 > B, Group C: A > C3 > C2 > C1 > C, Group D: A > D4 > D1 = D2 ≥ D3. Debonded surfaces showed adhesive failure in Group B while cohesive failure in Groups C and D.

Conclusions:

Cleansing treatments differ according to bonding step; re-etching then rebonding suggested if etched substrate or polymerized adhesive were contaminated while acetone application decontaminated affected unpolymerized adhesive.

Bonding of contemporary glass ionomer cements to different tooth substrates; microshear bond strength and scanning electron microscope study

OBJECTIVE

This study was conducted to evaluate the microshear bond strength (μSBS) and ultramorphological characterization of glass ionomer (GI) cements; conventional GI cement (Fuji IX, CGI), resin modified GI (Fuji II LC, RMGI) and nano-ionomer (Ketac N100, NI) to enamel, dentin and cementum substrates.

MATERIALS AND METHODS

Forty-five lower molars were sectioned above the cemento-enamel junction. The occlusal surfaces were ground flat to obtain enamel and dentin substrates, meanwhile the cervical one-third of the root portion were utilized to evaluate the bonding efficacy to cementum substrate. Each substrate received microcylinders from the three tested materials; which were applied according to manufacturer instructions. μSBS was assessed using a universal testing machine. The data were analyzed using two-way analysis of variance (ANOVA) and Tukey's post-hoc test. Modes of failure were examined using stereomicroscope at ×25 magnification. Interfacial analysis of the bonded specimens was carried out using environmental field emission scanning electron microscope.

RESULTS

Two-way ANOVA revealed that materials, substrates and their interaction had a statistically significant effect on the mean μSBS values at P values; ˂0.0001, 0.0108 and 0.0037 respectively. RMGI showed statistically significant the highest μSBS values to all examined tooth substrates. CGI and RMGI show substrate independent bonding efficiency, meanwhile; NI showed higher μSBS values to dentin and cementum compared to enamel.

CONCLUSION

Despite technological development of GI materials, mainly the nano-particles use, better results have not been achieved for both investigations, when compared to RMGI, independent of tooth substrate.

In vitro Comparative Evaluation of Tensile Bond Strength of 6(th), 7(th) and 8(th) Generation Dentin Bonding Agents

BACKGROUND

Newer dentin bonding agents were developed to improve the quality of composite restoration and to reduce time consumption in its application. The aim of the present study was to evaluate tensile bond strength of 6(th), 7(th) and 8(th) generation bonding agents by in vitro method.

MATERIALS AND METHODS

Selected 60 permanent teeth were assigned into 20 in each group (Group I: 6(th) generation bonding agent-Adper SE plus 3M ESPE, Group II: 7(th) generation bonding agent-G-Bond GC Corp Japan and Group III: 8(th) generation dentin adhesives-FuturaBond, DC, Voco, Germany). With high-speed diamond disc, coronal dentin was exposed, and selected dentin bonding agents were applied, followed by composite restoration. All samples were saved in saline for 24 h and tensile bond strength testing was done using a universal testing machine. The obtained data were tabulated and statistically analyzed using ANOVA test.

RESULTS

The tensile bond strength readings for 6(th) generation bonding agent was 32.2465, for 7(th) generation was 31.6734, and for 8(th)-generation dentine bonding agent was 34.74431. The highest tensile bond strength was seen in 8(th) generation bonding agent compared to 6(th) and 7(th) generation bonding agents.

CONCLUSION

From the present study it can be conclude that 8(th) generation dentine adhesive (Futura DC, Voco, Germany) resulted in highest tensile bond strength compared to 6(th) (Adper SE plus, 3M ESPE) and 7(th) generation (G-Bond) dentin bonding agents.

Effects of pulp capping materials on fracture resistance of Class II composite restorations

OBJECTIVE

The aim of this study was to investigate the effect of cavity design and the type of pulp capping materials on the fracture resistance of Class II composite restorations.

MATERIALS AND METHODS

Sixty freshly extracted, sound molar teeth were selected for the study. A dovetail cavity on the mesio-occlusal and a slot cavity on disto-occlusal surfaces of each tooth were prepared, and the teeth were divided 4 groups which one of them as a control group. The pulp capping materials (TheraCal LC, Calcimol LC, Dycal) applied on pulpo-axial wall of each cavity, and the restoration was completed with composite resin. The teeth were subjected to a compressive load in a universal mechanical testing machine. The surfaces of the tooth and restoration were examined under a stereomicroscope. The data were analyzed using factorial analysis of variance and Tukey's test.

RESULTS

For pulp capping materials, the highest fracture load (931.15 ± 203.81 N) and the lowest fracture load (832.28 ± 245.75 N) were calculated for Control and Dycal group, respectively. However, there were no statistically significant differences among all groups (P > 0.05). The fracture load of the dovetail groups was significantly higher than those of the slot cavity groups (P < 0.05).

CONCLUSION

Dovetail cavity design shows better fracture resistance in Class II composite restorations, independent of used or not used pulp capping materials.

Effect of sodium hypochlorite and peracetic acid on the surface roughness of acrylic resin polymerized by heated water for short and long cycles

OBJECTIVE

To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3).

MATERIALS AND METHODS

The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test.

RESULTS

There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances.

CONCLUSION

It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness.