Effect of Dentin Disinfection with 2% Chlorhexidine Gluconate and 0.3% Iodine on Dentin Bond Strength: An in vitro Study

Synthesis and characterization of mesoporous zinc oxide nanoparticles and evaluation of their biocompatibility in L929 fibroblasts

OBJECTIVES

This study aimed to synthesize and characterize mesoporous zinc oxide nanoparticles (ZnO NPs) and also to evaluate the cytotoxicity of mesoporous ZnO NPs on L929 mouse fibroblast cell lines using 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.

MATERIALS AND METHODS

The synthesized mesoporous ZnO NPs were extensively characterized using X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectra (EDAX), Fourier-transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS). The cytotoxicity of mesoporous ZnO NPs was assessed by MTT assay. The study groups for cytotoxicity assay were normal saline, 0.1% calcined mesoporous ZnO NP solution, 1% calcined mesoporous ZnO NP solution, 0.1% noncalcined mesoporous ZnO NP solution, 1% noncalcined mesoporous ZnO NP solution, 0.1% ZnO NP solution, 1% ZnO NP solution, 2% chlorhexidine, and phosphate-buffered saline (PBS). The percentages of mean ± standard deviation of viable cells were analyzed.

RESULTS

Characterization of mesoporous ZnO NPs revealed that all the particles were in a more or less spherical shape with a wide particle size distribution of 70-100 nm. TEM image showed the uniformed and aggregated ZnO NPs with a typical size of 10-15 nm. BET analysis showed a mesoporous structure for the prepared mesoporous ZnO NPs. According to the MTT assay, chlorhexidine had the lowest cell viability percentage. Cell viability percentages of 0.1% mesoporous ZnO NP solutions (calcined and noncalcined) were statistically, significantly higher than 0.1% ZnO NP solution (p < .05). Cell viability percentages of 0.1% calcined and noncalcined mesoporous ZnO NP solutions and 0.1% ZnO NP solution were statistically, significantly higher than the 1% solutions (p < .05).

CONCLUSION

Mesoporous ZnO NPs exhibited less cytotoxicity against L929 mouse fibroblast cell lines compared to CHX and ZnO NPs, hence are safe to use.

Adhesive Bond Strength of Restorative Materials to Caries-Affected Dentin Treated with Antimicrobial Photodynamic Therapy: A Systematic Review and Meta-Analysis

Objective: This systematic review aimed to evaluate the adhesive bond strength of restorative materials to caries-affected dentin (CAD) treated with antimicrobial photodynamic therapy (aPDT) in comparison with conventional chemical disinfectants. Methods: Three databases, including the Web of Science, Scopus, and PubMed, were searched to address the focused question: "What is the effect of aPDT compared to conventional chemical disinfection techniques on the adhesive bond strength of restorative materials to CAD?." Search keywords included "dentin*" "adhes bond*" "caries-affected dentin" "photodynamic "photochemotherapy" "photosensitizing agent" "phototherapy" "photoradiation" "laser" "light activated" "photoactivated." A fixed-effects model was used in each meta-analysis and the inverse variance was used to calculate the standard mean difference (SMD). For evaluating the statistical heterogeneity, the Cochrane's Q test and the I2 statistics were used. The risk of bias was evaluated based on the Cochrane Collaboration's tool. Results: Fourteen studies were included in the qualitative as well as quantitative analysis. The results of the meta-analyses exhibited an SMD of 2.38% [95% confidence interval (CI): 2.03-2.73; p < 0.00001], indicating a statistically significant difference in the shear bond strength scores between the tested group (samples treated with aPDT) and the control group (i.e., favoring the sound dentin and/or conventional chemical disinfectants). Contrarily, an SMD of -1.46% (95% CI: -2.04 to -0.88; p < 0.00001) and -0.37% (95% CI: -0.70 to -0.03; p = 0.03) was observed, indicating a statistically significant difference in the microtensile bond strength (μTBS), as well as microleakage scores between the tested group (favoring the samples treated with aPDT) and the control group (i.e., sound dentin and/or conventional chemical disinfectants). Conclusions: Adhesive bond strength of restorative materials to CAD treated with conventional chemical disinfectants showed superior outcomes compared to photodynamic therapy (aPDT).

Micro Tensile bond strength and microleakage assessment of total-etch and self-etch adhesive bonded to carious affected dentin disinfected with Chlorhexidine, Curcumin, and Malachite green

AIMS AND OBJECTIVES

Assessment of micro tensile bond strength (microTBS) and micro-leakage scores of total-etch adhesive (TAE) and self-etch adhesive (SAE) bonded to carious affected dentin (CAD) sterilized using different cavity disinfectant (curcumin photosensitizer (CP) and malachite green (MG) and Chlorhexidine (CHX) in comparison to no disinfection (ND) control group.

MATERIALS AND METHODS

One hundred and twenty human molars having International Caries Detection and Assessment System (ICDAS) scores of 4 and 5 were included. Visual inspection, dental explorer hardness testing, and caries detector solution using 5% basic Fuchsin dye solution was applied to dentin to identify the CAD surface. All the specimens were divided into four groups (n = 30) according to the cavity disinfectants used. Group A: 2% CHX, Group B: CP, Group C: MG, and Group D: ND. Each group was further divided into two subgroups (n = 15) based on the adhesion protocol. Groups A1, B1, C1, and D1 were held using TEA, and groups A2, B2, C2, and D2 were adhered using SEA system. The composite material was then built in 2 mm increments and then cured with light. MicroTBS and failure mode assessment using a universal testing machine (UTM) and stereomicroscope at a 40X magnification was performed on 10 samples from each subgroup. The microleakage assessment was performed using a dye penetration test on five samples from each group. ANOVA and Tukey post-hoc tests were used to compare means and standard deviation (SD) of bond strength and microleakage (p < 0.05). RESULTS The maximum microTBS was displayed by A1= CHX and TEA (13.28± 1.01 MPa). The lowest bond scores were demonstrated by C2= MG and SEA (5.98±0.44 MPa). The highest micro-leakage was exhibited by C1= MG and TEA (58.32 ± 2.11 nm). Whereas, the lowest micro-leakage values were displayed by A2= CHX and SEA (24.34± 1.11 nm).

CONCLUSION

Chlorohexidiene displayed better bond strength and the lowest microleakage scores with Total-etch adhesive and Self-etch adhesives when used as a cavity disinfectant. Total-etch adhesives performed better in terms of microTBS scores whereas self-etch adhesives displayed superior seal ability within the same disinfectant group.

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.

Mechanical Properties and Antibacterial Effect on Mono-Strain of Streptococcus mutans of Orthodontic Cements Reinforced with Chlorhexidine-Modified Nanotubes

Recently, several studies have introduced nanotechnology into the area of dental materials with the aim of improving their properties. The objective of this study is to determine the antibacterial and mechanical properties of type I glass ionomers reinforced with halloysite nanotubes modified with 2% chlorhexidine at concentrations of 5% and 10% relative to the total weight of the powder used to construct each sample. Regarding antibacterial effect, 200 samples were established and distributed into four experimental groups and six control groups (4 +ve and 2 -ve), with 20 samples each. The mechanical properties were evaluated in 270 samples, assessing microhardness (30 samples), compressive strength (120 samples), and setting time (120 samples). The groups were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, and the antibacterial activity of the ionomers was evaluated on Streptococcus mutans for 24 h. The control and positive control groups showed no antibacterial effect, while the experimental group with 5% concentration showed a zone of growth inhibition between 11.35 mm and 11.45 mm, and the group with 10% concentration showed a zone of growth inhibition between 12.50 mm and 13.20 mm. Statistical differences were observed between the experimental groups with 5% and 10% nanotubes. Regarding the mechanical properties, microhardness, and setting time, no statistical difference was found when compared with control groups, while compressive strength showed higher significant values, with ionomers modified with 10% concentration of nanotubes resulting in better compressive strength values. The incorporation of nanotubes at concentrations of 5% and 10% effectively inhibited the presence of S. mutans, particularly when the dose-response relationship was taken into account, with the advantage of maintaining and improving their mechanical properties.

Disinfection of caries affected dentin using Rose Bengal, Titanium Sapphire Laser; Ammonium Hexa-fluorosilicate, and ozonated water on resin dentin bond strength

AIM

The present study intended to evaluate the shear bond strength (SBS) of resin cement bonded to caries affected dentin (CAD) after disinfection with rose Bengal (RB), Ti-Sapphire Laser, Ammonium Hexafluorosilicate (NH₄)₂[SiF₆], and ozonated water (O₃) MATERIAL AND METHODS: A total of 100 extracted human mandibular molars were acquired using caries severity code, 6 of the ICDAS criteria. To achieve homogeneity and prevent size-biased distributions, the average cavity preparation of all specimens had a depth of 2 mm and a breadth of 3 mm. Specimens were divided into five groups (n = 20) at random according to type of disinfection. Group 1: control group, Group 2: RB, Group 3: O₃, Group 4: Ti-sapphire laser, and Group 5: (NH4)2[SiF₆]. All specimens were etch and rinsed, bonding agent was applied and restored with resin cement. Estimation of SBS was performed by placing samples (10/group) in universal testing machine. Stereomicroscope under 40 × magnification was employed for failure mode analysis (FMA). Statistical analysis was executed using the ANOVA and the Tukey multiple test (p<0.05).

RESULTS

The highest SBS was demonstrated in the control group when CAD bonded to resin cement without disinfection (18.22±1.14 MPa). Likewise, the lowest SBS values were unveiled by CAD disinfection with O₃ (12.44±1.36 MPa). Similarly, CAD when disinfected with RB (16.25±1.01 MPa) and Ti-sapphire laser (16.25±1.22 MPa) bonded to resin cement exhibited comparable bond results (p>0.05).

CONCLUSION

Caries affected dentin when treated with etch and rinse technique without the use of disinfectant displayed the highest SBS. However, it was seen that utilization of various disinfectants has altered the adhesion capacity or bonding efficacy of caries-affected dentin.

Evaluation of the Effect of Anti-COVID-19 Mouthwashes on Shear Bond Strength of Composite Resin Restorations to Dentin and Enamel: An “In Vitro Study”

Objectives

Given the high prevalence of the coronavirus and the high risk of virus transfer to dentists, the use of mouthwashes, which can potentially eliminate this virus, is suggested before dental procedures. Since these mouthwashes may affect the bond strength of composite resin restorations to teeth, this study was conducted to investigate the effect of recommended mouthwashes on the shear bond strength of composite resin restorations to dentin and enamel in selective etch and rinse and two-step self-etch bonding systems.

Methods

Five groups of posterior teeth (n = 15) were selected for five groups of cetylpyridinium chloride 0.07%, povidone-iodine 1%, hydrogen peroxide 1%, and chlorhexidine 0.2% as mouthwash and distilled water as the control group. The buccal enamel and lingual dentin of each tooth were rinsed after immersion in a mouthwash. After 20 seconds of enamel acid-etching and 15 seconds of dentin priming, they were impregnated with an adhesive, and composite cylinders were placed on the dentin and enamel surfaces of the tooth. The shear bond strength test was performed after 24 hours, and results were analyzed by ANOVA and paired t-test (α = 0.05).

Results

The mean shear bond strength of enamel to composite was significantly (p < 0.05) higher than that of dentin to composite in each study group, but no significant difference was found between the mean shear bond strength of composite to enamel (p = 0.199) and to dentin (p = 0.335) after the use of mouthwashes and that of the control group.

Conclusion

The use of mouthwashes used in this study did not have negative effects on the shear bond strength of composite to enamel and dentin.

Effect of Different Mouthwashing Regimens on Adhesion of a Universal Adhesive:A Microshear Bond Strength and Scaning Electron Microscopy Evaluation

Objective: To evaluate the effect of probiotic or chlorhexidine-based mouthwashes and coconut oil pulling therapy on microshear bond strength of a universal adhesive, used with two application modes. Method: Ninety-six enamel specimens were prepared using bovine incisors and the surfaces were grounded. Then the specimens were randomly divided into 4groups and each group were subjected to a mouth washing regimen with one of three agents-chlorhexidine mouthwash, probiotic-based mouthwash, coconut oil pulling – or stored in artificial saliva(control) for 7 days(n=24). After the procedure, all groups were divided into 2 subgroups, and a universal adhesive was applied with etch-and-rinse or self-etch mode(n=12). Composite micro-cylinders were bonded to the enamel surfaces and micro-shear-bond strength was measured after 24hours water storage. Failure modes were determined using a stereomicroscope and SEM analysis was also performed. The data were analyzed using Mann-Whitney-U and Kruskal-Wallis tests. Results: No significant differences were observed between the different mouthwash groups, regardless of application modes(p> .05). There were no significant differences in microshear-bond strength, within the same mouthwash groups, between self-etch or etch-and-rinse modes, except for oil pulling group. Etch-and-rinse group showed higher bond strength than self-etch group in specimens subjected to oil pulling(p< .05). Conclusion: Etch-and-rinse mode might be preferable on patients who practice oil pulling.

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 Disinfection with Chlorhexidine on Marginal Gap of Class V Composite Restorations Bonded with a Universal Adhesive Using Self-Etch and Etch-and-Rinse Bonding Strategy

Objectives:

This in-vitro study aimed to evaluate the effect of cavity disinfection with chlorhexidine (CHX) on marginal gaps of Class V composite resin restorations bonded with a universal adhesive using self-etch and etch-and-rinse bonding strategy.

Materials and Methods:

Sixty sound human premolars were randomly assigned to two groups (n=30): group 1 (CHX) and group 2 (no CHX). Each group was divided into two subgroups (n=15) according to the bonding strategy of the universal adhesive (self-etch or etch-and-rinse). Class V cavities were prepared on the buccal surfaces of the teeth. The occlusal and gingival margins of the cavities were placed in enamel and dentin, respectively. In the first and second subgroups of both groups, the All-Bond Universal adhesive was applied with self-etch and etch-and-rinse bonding strategy, respectively. After restoration and thermocycling, the samples were sectioned, and marginal gaps at the gingival margins were measured in micrometer (μm) under a stereomicroscope. Two-way analysis of variance (ANOVA) was used to compare marginal gaps between the groups and the subgroups.

Results:

The mean marginal gap size was significantly affected by cavity disinfection (P=0.001) and bonding strategy (P=0.002). However, the interaction effect of these two factors on the mean marginal gap size was not significant (P=0.79).

Conclusion:

The use of CHX resulted in larger marginal gaps at the gingival margins of Class V composite resin restorations. Irrespective of disinfection, the self-etch bonding strategy resulted in larger marginal gaps compared to the etch-and-rinse bonding strategy.

Shear bond strength of the adhesive/dentin interface after different etching protocols

Background:

Aim:

Materials and Methods:

Results:

Conclusion:

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.

Efficacy of chlorhexidine, Er Cr YSGG laser and photodynamic therapy on the adhesive bond integrity of caries affected dentin. An in-vitro study

AIM

To evaluate the adhesive bond integrity (shear bond strength-SBS) of composite resin bonded to carious dentin using chlorhexidine gluconate (CHX), Er,Cr:YSGG laser (ECYL) and photodynamic therapy (PDT).

MATERIAL AND METHODS

Thirty carious and ten non-carious mandibular teeth were collected through non-traumatic extraction. All samples were embedded in polyvinyl cross-sections to the cemento-enamel junction. The preparation of caries-affected dentin was performed by grinding the specimens using silicon carbide discs. All specimens were randomly allocated in to four groups (n = 10). Group 1, non-affected dentin with no disinfection; Group 2, caries affected dentin treated with 2% CHX; Group 3, affected dentin disinfected with PDT [100 mg/L methylene blue solution (MBS) and Diode laser]; Group 4, affected dentin treated with ECYL. Self-etch adhesive was smeared on all specimens for 10 s and photopolymerized for 10 s. All specimens were placed in an incubator with humid environment for 24 h at 37 °C followed by positioning in universal testing machine for SBS testing. Failure mode examination of debonded samples was performed by a stereomicroscope. Analysis of variance (ANOVA) was used for inter group comparison through mean and standard deviation of each group. For multiple group comparison Tukey HSD was employed. Level of significance was established at p < 0.05.

RESULTS

The highest SBS value was observed in group 1 (24.98 ± 1.59 MPa). Whereas, the lowest bond strength was displayed by group 3 (14.22 ± 1.40 MPa) specimens. Lased dentin in group 4 (15.89 ± 3.22 MPa) exhibited SBS values comparable to group 3 (14.22 ± 1.40 MPa). Group 2 (CHX-18.25 ± 1.29 MPa) exhibited statistically significant difference compared to all experimental groups (p < 0.05).

CONCLUSIONS

Adhesive bond strength of disinfected carious dentin was higher with CHX treatment as compared to Photodynamic therapy and Er,Cr: YSGG laser treatment. Carious dentin showed lower bond strength to composite resin as compared to non-carious dentin.

Influence of different application protocols of universal adhesive system on the clinical behavior of Class I and II restorations of composite resin - a randomized and double-blind controlled clinical trial

Background

Multimode adhesives incorporate the versatility of adapting to various clinical situations by its capacity to be used in different protocols. This study aimed to evaluate the clinical behavior of composite resin direct restorations (Class I and II) performed with different universal dentin adhesive application protocols comparing adapted FDI and adapted USPHS criteria.

Methods

The current study is a randomized, double-blind, split-mouth, and convenience sample controlled clinical trial. The participants (age ≥ 18 years) had restorative need of Class I and/or II due to the presence of carious lesions and/or unsatisfactory restorations in at least three dental elements. Each participant received three application protocols for Scotchbond Universal adhesive (3M ESPE), one in each tooth to be restored: ER = etch-and-rinse + adhesive (n = 50); SEE = selective enamel etch + adhesive (n = 50) and SE = self-etch adhesive (n = 50). All teeth were restored in a similar way using Filtek™ Supreme composite resin (3M ESPE). Restorations were evaluated using the adapted FDI and adapted USPHS criteria, at baseline after 7 to 21 (12.02 ± 5.68) days (T1; n = 50 per group) and after 12 to 20 (15.8 ± 2.7) months (T2; n = 46 per group) by two previously calibrated evaluators (Kappa > 0.80). The statistical tests were performed between groups (Friedman), intragroup (Wilcoxon), and between the criteria considering acceptable and not acceptable restorations (McNemar), α = 0.05.

Results

A statistically significant difference was observed only for the property “superficial staining”, between groups at T2 (p = 0.01) for ER (n = 13 with score 2 or more) and SEE (n = 3 with score 2 or more) and intragroup for ER (T1, n = 1 with score 2 or more; T2, n = 13 with score 2 or more, p = 0.001) and SE (T1, n = 0 with score 2 or more; T2, n = 8 with score 2 or more p = 0.007). For the other comparisons between groups, intragroup, and between the adapted FDI and adapted USPHS criteria, there were no statistically significant differences (p ≥ 0.05).

Conclusions

It can be concluded that the different application protocols of the universal adhesive resulted in clinically “acceptable” restorations after 15.8 ± 2.7 months of follow-up. Adapted FDI and adapted USPHS criteria provided similar results to each other.

Trial registration.

Number in Brazilian Registry of Clinical Trials (ReBEC): RBR-9p3hdp. Registered 24 May 2015.

Quaternary ammonium silane-based antibacterial and anti-proteolytic cavity cleanser

OBJECTIVE

Secondary caries and degradation of hybrid layers are two major challenges in achieving durable resin-dentin bonds. The objectives of the present study were to investigate the effects of a 2% quaternary ammonium silane (QAS) cavity cleanser on bacteria impregnated into dentin blocks and the gelatinolytic activity of the hybrid layers.

METHODS

Microtensile bond strength was first performed to evaluate if the 2% QAS cavity cleanser adversely affected bond strength. For antibacterial testing, Streptococcus mutans and Actinomyces naeslundii were impregnated into dentin blocks, respectively, prior to the application of the cavity cleanser. Live/dead bacterial staining and colony-forming unit (CFU) counts were performed to evaluate their antibacterial effects. Gelatinolytic activity within the hybrid layers was directly examined using in-situ zymography. A double-fluorescence technique was used to examine interfacial permeability immediately after bonding.

RESULTS

The cavity cleanser did not adversely affect the bond strength of the adhesives tested (p>0.05). Antibacterial testing indicated that 2% QAS significantly killed impregnated bacteria within the dentin blocks compared with control group (p<0.05), which was comparable with the antibacterial activity of 2% chlorhexidine (p>0.05). Hybrid layers pretreated with 2% QAS showed significant decrease in enzyme activity compared with control group. With the use of 2% QAS, relatively lower interfacial permeability was observed, compared with control group and 2% chlorhexidine (p<0.05).

SIGNIFICANCE

The present study developed a 2% QAS cavity cleanser that possesses combined antimicrobial and anti-proteolytic activities to extend the longevity of resin-dentin bonds.