Effect of 2% iodine disinfecting solution on bond strength to dentin

Effect of Anti-COVID-19 Mouthwashes on Shear Bond Strength of Resin-Matrix Ceramics Repaired with Resin Composite Using Universal Adhesive: An In Vitro Study

Using anti-COVID-19 mouthwashes has become necessary to reduce acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmissions. Resin-matrix ceramic (RMCs) materials that are exposed to mouthwashes may affect the bonding of repaired materials. This research was performed to assess the effects of anti-COVID-19 mouthwashes on the shear bond strengths (SBS) of RMCs repaired with resin composites. A total of 189 rectangular specimens of two different RMCs (Vita Enamic (VE) and Shofu Block HC (ShB)) were thermocycled and randomly divided into nine subgroups according to different mouthwashes (distilled water (DW), 0.2% povidone–iodine (PVP-I), and 1.5% hydrogen peroxide (HP)) and surface treatment protocols (no surface treatment, hydrofluoric acid etching (HF), and sandblasting (SB)). A repair protocol for RMCs was performed (using universal adhesives and resin composites), and the specimens were assessed using an SBS test. The failure mode was examined using a stereomicroscope. The SBS data were evaluated using a three-way ANOVA and a Tukey post hoc test. The SBS were significantly affected by the RMCs, mouthwashes, and surface treatment protocols. Both surface treatment protocols (HF and SB) for both RMCs, whether immersed in anti-COVID-19 mouthwash or not, improved the SBS. For the VE immersed in HP and PVP-I, the HF surface treatment had the highest SBS. For the ShB immersed in HP and PVP-I, the SB surface treatment had the highest SBS.

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.

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 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.

Zinc oxide eugenol paste jeopardises the adhesive bonding to primary dentine

AIM

This was to evaluate the influence of root canal filling pastes on microshear bond strength (µSBS) of an adhesive system to primary dentine.

METHODS

Human (32) primary molars were randomly assigned into four experimental groups (n = 8): zinc oxide eugenol paste (ZOE); iodoform paste (Guedes-Pinto paste); calcium hydroxide paste thickened with zinc oxide; and no filling paste (control). Flat dentine surfaces were covered with a 1 mm-thick layer of the pastes for 15 min at 37 °C. The pastes were mechanically removed from dentine surfaces, followed by rinsing and drying. After adhesive application (Adper Single Bond 2, 3M ESPE), starch tubes were placed over pre-treated dentine and filled with composite resin (Z250, 3M ESPE). The µSBS test was performed after 24 h of water storage at 37 °C. The failure mode was evaluated using a stereomicroscope. The µSBS values (MPa) were analysed with one-way ANOVA and Tukey post-hoc tests (α = 0.05).

RESULTS

The lowest µSBS values were achieved when ZOE was used. No difference was found among other filling pastes compared with control group. All specimens showed adhesive/mixed failures.

CONCLUSIONS

Zinc oxide eugenol paste negatively influenced the bond strength of adhesive systems to primary dentine. Iodoform-based Guedes-Pinto paste and calcium hydroxide paste thickened with zinc oxide did not influence the microshear bond strength values.

Analysis by confocal laser scanning microscopy of the MDPB bactericidal effect on S. mutans biofilm CLSM analysis of MDPB bactericidal effect on biofilm

Since bacteria remain in the dentin following caries removal, restorative materials with antibacterial properties are desirable to help maintaining the residual microorganisms inactive. The adhesive system Clearfil Protect Bond (PB) contains the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) in its primer, which has shown antimicrobial activity. However, its bactericidal effect against biofilm on the dentin has been little investigated.

Evaluation of effect of different cavity disinfectants on shear bond strength of composite resin to dentin using two-step self-etch and one-step self-etch bonding systems: a comparative in vitro study

AIM AND OBJECTIVES

To evaluate the effect of 2% chlorhexidine, 2% sodium hypochlorite, 3% hydrogen peroxide on shear bond strength of composite resin to dentin using two-step and onestep self-etch bonding systems and to study the mode of failure of specimens under stereomicroscope.

MATERIALS AND METHODS

Eighty extracted sound human posterior teeth were used. The occlusal surfaces were ground to expose the dentin and were then randomly divided into 4 main groups. In group I, no cavity disinfectant was used and served as control. In groups II, III, IV, 2% chlorhexidine, 2% sodium hypochlorite and 3% hydrogen peroxide were used as cavity disinfectants respectively. Each group was then divided into two subgroups of 10 teeth each according to the bonding agent used, two-step self-etch (Adper SE Plus) and one-step self-etch (Adper Easy One) respectively. A transparent cylindrical plastic tube was loaded with microhybrid composite and placed over the dentin and light cured for 40 seconds. The specimens were subjected to shear stress in the universal testing machine.

RESULTS

Pretreatment with 2% chlorhexidine, 2% sodium hypochlorite and 3% hydrogen peroxide, had a negative effect on the shear bond strength of self-etching bonding systems.

CONCLUSION

The highest bond strength was found in 2% chlorhexidine group followed by 2% sodium hypochlorite group and the lowest bond strength was found in 3% hydrogen peroxide group.

CLINICAL SIGNIFICANCE

All three cavity disinfectants used in this study reduced the shear bond strength and hence should be used with caution.