Effects of the application sequence of calcium-containing desensitising pastes during etch-and-rinse adhesive restoration

Influence of the combined effect of desensitizing dentifrices and universal adhesives on dentin bond strength under erosive conditions

OBJECTIVE

This study aimed to evaluate whether the use of desensitizing dentifrices containing obliterating agents can affect bond strength of eroded/abraded dentin.

METHODOLOGY

A total of 100 dentin samples were obtained from human molars. The teeth were cut into 3 mm-thickness discs and allocated in five groups (n=20), according to the toothpaste used: WoF - abrasion with fluoride-free toothpaste (Cocoricó); Arg - toothpaste containing arginine (Colgate Sensitive Pro-Relief); Nov - calcium sodium phosphosilicate toothpaste (Sensodyne Repair and Protect); SnF - fluoride-containing toothpaste (AmF/SnCl2/SnF2 - Elmex Erosion); and Control (no erosive/abrasive process). The erosive/abrasive cycle consisted of immersion in citric acid (1%, pH 2.6, 5 min, 4×/day) and abrasion (2×/day, 120-20 sec abrasion, 100 sec immersion) with each toothpaste. During intervals, samples were immersed in artificial saliva. This cycle was performed for five days. Two resin cylinders (2 mm in diameter) were constructed on each sample for the shear bond strength test using a universal adhesive system. The self-etch and etch-and-rinse (Scotchbond Universal) strategies were employed, each in half of the total sample (n=10). Bond strength (MPa) was measured in a shear test and failure modes were assessed with a stereomicroscope. Statistical analysis was performed using the two-way analysis of variance (ANOVA) and Tukey tests (p<0.05).

RESULTS

A statistically significant difference was found between the adhesive strategies tested (p<0.001), with the self-etching form showing higher values than the etch-and-rinse. Moreover, no significant differences were observed between the tested toothpastes (p=0.750) and interactions (p=0.438).

CONCLUSION

The use of toothpaste containing obliterating agents does not affect bond strength to dentin subjected to erosive/abrasive conditions when a universal adhesive is used. However, the self-etch strategy might be preferred for eroded/abraded dentin.

Effects of Arginine-calcium carbonate pretreatment on the remineralizing and bonding performance of phosphorylated dentin

OBJECTIVES

To evaluate the effects of Arginine-calcium carbonate (Arg-CaCO₃) paste treatment of phosphorylated dentin on remineralizing and bonding performance during direct and indirect restorations under pulpal pressure.

METHODS

Under simulated pulpal pressure, dentin of healthy third molars were abraded and acid etched for 15s, then randomly divided into 4 groups: negative control group; Arg-CaCO₃ group (1min); 2.5% Sodium trimetaphosphate (STMP) group (3min); S-A group, 2.5% STMP + Arg-CaCO₃. After 24h, remineralization and dentin tubular occlusion were assessed by Attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR), Micro-Raman spectroscopy, Vickers hardness, Field-emission scanning electron microscope (FESEM) and Energy X-ray dispersive spectrometer (EDS). The liquid environment was the simulated body fluid (SBF) permeated from dentin tubules due to pulpal pressure. Stick specimens prepared with self-etch dentin adhesive were tested for microtensile bond strength (μTBS) and interfacial silver nanoleakage on both immediate direct restoration and indirect restoration with a 7-day temporary period. Data were analyzed by the Kruskal-Wallis test, Mann-Whitney test, Welch ANOVA or one-way ANOVA and Tukey post hoc test (p < 0.05).

RESULTS

The pretreatment of 2.5% STMP with Arg-CaCO₃ significantly increased relative mineral content by ATR-FTIR, Raman and FESEM-EDS, simultaneously enhancing dentin tubular occlusion (%) and mechanical property to the most considerable extent. Furthermore, the pretreatment significantly promoted the μTBS of indirect restoration and reduced nanoleakage after 7 days.

CONCLUSIONS

The application of Arg-CaCO₃ paste on phosphorylated dentin could improve intra- and extra-tubular mineralization and the stability of adhesion interface.

CLINICAL RELEVANCE

Without exceeding the amount of conventional tooth preparation, combining 2.5% STMP with Arg-CaCO₃ paste before the self-etch bonding system might be a promising clinical strategy to relieve dentin hypersensitivity and strengthen bonding performance efficiently and conveniently.

The effect of desensitizing agents on the bond strength of dentin bonding agents: A systematic review

Background

Dentinal hypersensitivity (DH) is a common dental problem and is treated non-invasively using topical application of various desensitizing agents. When there is loss of tooth structure or tooth preparation is to be followed by a bonded restoration, it requires application of dentin bonding agent. However, the effect of desensitizers on bond strength is still controversial.

Aim and Objective

To evaluate the influence of different desensitizing agents on the bond strength of the dentin bonding agents.

Methods and Materials

PICO strategy was used to formulate the research question. In-vitro studies conducted on human teeth to evaluate the bond strength of dentin bonding agent following the application of desensitizing agent were included. Electronic databases PubMed and Cochrane and google scholar were searched using search terms alone or in combination from the year 2010 till 2020. Search was conducted using the key words and MeSH terms (hypersensitivity, bond strength, dental adhesives, dentin bonding agents). The title and abstract were read to verify the inclusion and exclusion criteria and if further any details required, full article was accessed to check the criteria and then included or excluded. Data extraction was done using a customized data extraction form. The risk of bias was evaluated using modified Cochrane Collaboration Quality Assessment tool.

Results

Total no of studies identified in the search were 146, after scrutiny 23 articles were eligible to be included in this study. Out of 23 articles, 17 articles were of medium bias and 6 articles were of high risk after risk of bias assessment.

Conclusion

According to the various articles included in this study, GLUMA and 8.0%Arginine and CaCO3 when used as desensitizing agents along with different bonding agents, were found to be highly compatible without interfering with the bond strength of the dentin adhesives.

Influence of diode laser treatment and casein phosphopeptide-amorphous calcium phosphate paste on eroded root dentin

Introduction

It is still unclear whether the pretreatment for dentin hypersensitivity can interfere with the adhesive-dentin bonding strength. This study aimed to evaluate in vitro the effect of pretreatment with a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste and diode laser on the shear bond strength of the etch-and-rinse adhesive system in the adhesive-dentin interface.

Materials and Methods

Seventy-five bovine root specimens were randomly divided into five experimental groups (n = 15). Samples were eroded by six cycles of immersion in hydrochloric acid solution (0.01M; pH = 1.2) for 20 s each, at 45 min intervals, and treated with: G2 - no treatment, G3 - CPP-ACP, G4 - diode laser (970 nm), and G5 - CPP-ACP + Diode laser. After treatments, the morphology of the specimens was analyzed.

Results

The fracture mode of each group was evaluated after restoration with composite resins in the treated area. Data were analyzed by the one-way ANOVA and Tukey's test (P < 0.05). G3 showed the highest values for shear bond strength; there was no significant difference among G1, G3, and G5 (P > 0.05). The adhesive fracture was predominant for all groups.

Conclusion

The use of desensitizers containing CPP-ACP, associated or not with a diode laser, increased the bond strength of the etch-and-rinse adhesive system on eroded root dentin.

The Stability of Dentin Surface Biobarrier Consisting of Mesoporous Delivery System on Dentinal Tubule Occlusion and Streptococcus Mutans Biofilm Inhibition

Background

The dentin exposure always leads to dentin hypersensitivity and/or caries. Given the dentin’s tubular structure and low mineralization degree, reestablishing an effective biobarrier to stably protect dentin remains significantly challenging. This study reports a versatile dentin surface biobarrier consisting of a mesoporous silica-based epigallocatechin-3-gallate (EGCG)/nanohydroxyapatite delivery system and evaluates its stability on the dentinal tubule occlusion and the Streptococcus mutans (S. mutans) biofilm inhibition.

Materials and Methods

The mesoporous delivery system was fabricated and characterized. Sensitive dentin discs were prepared and randomly allocated to three groups: 1, control group; 2, casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) group; and 3, the mesoporous delivery system group. The dentin permeability, dentinal tubule occlusion, acid and abrasion resistance, and S. mutans biofilm inhibition were determined for 1 week and 1 month. The in vitro release profiles of EGCG, Ca, and P were also monitored.

Results

The mesoporous delivery system held the ability to sustainably release EGCG, Ca, and P and could persistently occlude dentinal tubules with acid and abrasion resistance, reduce the dentin permeability, and inhibit the S. mutans biofilm formation for up to 1 month compared with the two other groups. The system provided prolonged stability to combat oral adverse challenges and served as an effective surface biobarrier to protect the exposed dentin.

Conclusion

The establishment of the dentin surface biobarrier consisting of a mesoporous delivery system indicates a promising strategy for the prevention and the management of dentin hypersensitivity and caries after enamel loss.

Bond Strength of Universal Adhesives to Dentin: A Systematic Review and Meta-Analysis

Currently, the availability of a wide variety of universal adhesives makes it difficult for clinicians to choose the correct system for specific bonding situations to dentin substrate. This study aimed to determine whether there are any alternative techniques or additional strategies available to enhance the bond strength of universal adhesives to dentin through a systematic review and meta-analysis. Two reviewers executed a literature search up to September 2020 in four electronic databases: PubMed, ISI Web of Science, Scopus, and EMBASE. Only in vitro studies that reported the dentin bond strength of universal adhesives using additional strategies were included. An analysis was carried out using Review Manager Software version 5.3.5 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, Denmark). The methodological quality of each in vitro study was assessed according to the parameters of a previous systematic. A total of 5671 potentially relevant studies were identified. After title and abstract examination, 74 studies remained in systematic review. From these, a total of 61 studies were included in the meta-analysis. The bond strength of universal adhesives to dentin was improved by the use of one of the following techniques: Previous application of matrix metalloproteinases (MMP) inhibitors (p < 0.001), prolonged application time (p = 0.007), scrubbing technique (p < 0.001), selective dentin etching (p < 0.001), non-atmospheric plasma (p = 0.01), ethanol-wet bonding (p < 0.01), prolonged blowing time (p = 0.02), multiple layer application (p = 0.005), prolonged curing time (p = 0.006), and hydrophobic layer coating (p < 0.001). On the other hand, the use of a shortened application time (p = 0.006), and dentin desensitizers (p = 0.01) impaired the bond strength of universal adhesives to dentin. Most of the analyses performed showed a high heterogenicity. The in vitro evidence suggests that the application of universal adhesives using some alternative techniques or additional strategies may be beneficial for improving their bonding performance to dentin. This research received no external funding. Considering that this systematic review was carried out only with in vitro studies, registration was not performed.

Influences of desensitizing agents on bond strength of etch-and-rinse and self-etch adhesive system to dentin

Background:

Cervical lesions requiring adhesive restoration may present with dentin hypersensitivity, but the effect of desensitizer treatment on microtensile bond strength (MBS) is inconclusive.

Aim:

The aim of the present study was to assess the influence of two types of dentin desensitizing treatment on bond strength to dentin.

Materials and Methods:

Thirty-six extracted human mandibular first premolars were used to obtain superficial buccal cervical dentin. The samples were assigned to two groups (18/group): etch-and-rinse (ERS) (Optibond^® Solo) and self-etch (Palfique) adhesive systems. Eighteen teeth in each group were randomly assigned to three desensitizer treatments (6/treatment); control (no desensitization), Gluma™ desensitizerand Novamin-containing toothpaste (Sensodyne repair and protect™). Bonded dentin-composite specimens were stored in artificial saliva for 2 weeks prior to scanning electron microscope (SEM) evaluation and MBS testing. Univariate analysis of variance and Tukey tests were performed (α = 0.05) for the data analysis.

Results:

The mean MBS with self-etch system (SES) was significantly higher than ERS system, irrespective of the dentin desensitizer regimen. SEM showed no hybrid layer or resin tag formation in the SES group. Tubular occlusion was observed in all specimens treated with desensitizer.

Conclusion:

Mild self-etch adhesive can be used on dentin treated with Gluma or bioglass-containing desensitizer without compromising the bond strength.

Clinical Relevance:

Dentin desensitizer such as in-office Gluma or at-home Novamin-containing toothpaste could be used without compromising the bond strength of mild self-etch adhesive systems.

Effect of Casein Phosphopeptide-Amorphous Calcium Phosphate on Fracture Resistance of Reattached Tooth Fragments Using Conventional and Self-Adhesive Bioactive Flowable Composite

Objectives  The present study aimed to investigate the effect of casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) complex and the type of flowable composite (conventional or self-adhesive bioactive) on the fracture resistance of fractured incisors restored through reattachment technique.

Materials and Methods  In this experimental in vitro study, 60 extracted bovine central mandibular incisors were randomly divided into six groups ( n = 10) according to the reattachment technique. Their incisal edges were cut off to represent an enamel–dentin fracture. The fragment edges were reattached as follows: Group 1—selective etching and bonding followed by conventional flowable composite; Group 2—selective etching and bonding followed by bioactive flowable composite; Group 3 was like Group 2 but without applying bonding; Groups 4, 5, and 6 were similar to Groups 1, 2, and 3, respectively, but both tooth fragments were pretreated with CPP-ACP-containing paste for 3 minutes. Fracture resistance was assessed by a universal testing machine.

Statistical Analysis  Data were analyzed by SPSS—Statistical Package for the Social Sciences—software using one-way analysis of variance and Tukey post-hoc tests (α= 0.05).

Results  The highest and lowest fracture resistance was recorded in Groups 5 (15.96 MPa) and Group 6 (1.95 MPa), respectively, being significantly different from the other groups. The mean fracture resistance of Groups 3 and 6 was significantly lower than the other groups ( p < 0.05). However, Groups 1, 2, and 4 showed no difference in fracture resistance.

Conclusion  Bioactive composite was not superior to conventional composite for fragment reattachment, but using it in self-adhesive mode reduced the fracture strength significantly. Yet, pretreatment with CPP-ACP, followed by application of adhesive, improved the fracture resistance of bioactive composite.

In Vitro Study on the Effect of a New Bioactive Desensitizer on Dentin Tubule Sealing and Bonding

Bioactive mineral-based dentin desensitizers that can quickly and effectively seal dentinal tubules and promote dentin mineralization are desired. This in vitro study evaluated a novel nanohydroxyapatite-based desensitizer, Predicta (PBD, Parkell), and its effect on bond strength of dental adhesives. Human dentin discs (2-mm thick) were subjected to 0.5 M EDTA to remove the smear layer and expose tubules, treated with PBD, and processed for surface and cross-sectional SEM examination before and after immersion in simulated body fluid (SBF) for four weeks (ISO 23317-2014). The effects of two dental desensitizers on the microshear bond strength of a universal adhesive and a two-step self-etch system were compared. SEM showed coverage and penetration of nanoparticles in wide tubules on the PBD-treated dentin at the baseline. After four weeks in SBF, untreated dentin showed amorphous mineral deposits while PBD-treated dentin disclosed a highly mineralized structure integrated with dentin. Desensitizers significantly reduced microshear bond strength test (MSBS) of adhesives by 15-20% on average, depending on the bonding protocol. In conclusion, PBD demonstrated effective immediate tubules sealing capability and promoted mineral crystal growth over dentin and into the tubules during SBF-storage. For bonding to desensitizer-treated dentin, a two-step self-etching adhesive or universal bond with phosphoric acid pretreatment are recommended.

Effects of resveratrol/ethanol pretreatment on dentin bonding durability

To determine the effects of resveratrol/ethanol solution on the durability of resin-dentin bonding interfaces. Sixty-four non-caries third molars were randomly divided into four groups (n = 16) after sectioning, and then pretreated with one of the following concentrations of resveratrol/ethanol solutions: 0 (control group), 1, 10 and 20 mg/mL, followed by a universal adhesive and resin composites. All microtensile samples were divided into three subgroups: immediate group, collagenase ageing group and thermocycled group. The microtensile bond strength (MTBS), failure modes, interfacial nanoleakage and in situ zymography were measured, whereas the inhibitory effects of pretreated dentin slices on S. mutans biofilms were determined by confocal laser scanning microscopy and MTT assay. The results indicated that bonding strength was not only influenced by pretreatment factors (P < 0.05) but also ageing factors (P < 0.05). Regardless of collagenase ageing or thermocycling, the 10 mg/mL resveratrol/ethanol pretreatment group presented significantly higher (P < 0.05) MTBS and lower (P < 0.05) expression of nanoleakage than the control group, showed better inhibitory effect of matrix metalloproteinases and S. mutans activity with acceptable cytotoxicity. Meanwhile, cohesive failure in dentin decreased gradually with increasing resveratrol concentration. Therefore, the resveratrol/ethanol solution had the potential to serve as a versatile dentin primer, which can effectively improve dentin bonding durability and prevent secondary caries.

Evaluation of the Occluding Characteristics of Nanosized Eggshell/Titanium Dioxide with or without Saliva

OBJECTIVES

 The study reports on the effectiveness of a ball-milled nanosized titanium dioxide composite (EB@TiO₂) for DH management in comparison with commercial desensitizing paste with and without saliva.

MATERIALS AND METHODS

  Forty-nine dentine specimens were prepared from extracted bovine anterior teeth. Twenty-one of the specimens were brushed with three desensitizing toothpaste for 7 days, namely: Group 1; EB@TiO₂, Group 2; Colgate Pro-relief; and Group 3; Sensodyne repair (n = 7). Twenty-four specimens were brushed with the toothpaste for 7 days and stored in artificial saliva (control) after brushing. Each specimen was subsequently posttreated in citric acid solution to test its stability in acidic condition. Field scanning electron microscope was used to evaluate the effectiveness of the dentine tubules occlusion. The biocompatibility of the composite was tested using BHK21 cell line.

STATISTICAL ANALYSIS

 One-way analysis of variance was used to analyze the percentage occluded area ratio values for all specimens (α = 0.05). Independent t-test was further used to evaluate the occlusion differences with saliva and without saliva.

RESULTS AND CONCLUSIONS

 The number of dentine tubules decreased significantly after 7 days of brushing. Overall, the occlusion observe for EB@TiO₂ were significantly better than for Colgate Pro-relief and Sensodyne repair (p < 0.05). BHK21 assay suggested that composite had no significant effect on the BHK21 cell line. This study demonstrated that the composite effectively occluded open dentine tubules within 7 days of brushing.

Effect of Dentin Pretreatment with Arginine on Microshear Bond Strength of Etch-and-Rinse or Self-Etch Adhesive Systems

Objective The main purpose of this study was to evaluate the effect of dentin pretreatment with 8% arginine on the immediate and 6-month bond strength (BS) of adhesive systems and surface morphology of dentin.

Materials and Methods Dentin bovine specimens (5 × 5 mm) were allocated into following pretreatments: without pretreatment (conventional technique, C) or exposure to arginine solution (A) for 5 minutes prior to tooth restoration. The adhesive procedure was performed using ( n = 12): 3-step etch-and-rinse adhesive (Scotchbond Multipurpose—SBMP [C+SBMP and A+SBMP]); 2-step etch-and-rinse adhesive (Single Bond 2 - SB [C+SB and A+SB]); or 2-step self-etch adhesive (Clearfil SE Bond - CSEB [C+CSEB and A+CSEB]). After 24 hours, the composite resin restorations were evaluated immediately and after 6 months of water storage using a microshear test and fracture pattern. The dentin surface exposed to A was assessed by scanning electron microscopy (SEM). The immediate BS data were submitted to a two-way analysis of variance and Tukey's test, and the long-term BS results were analyzed using Kruskal–Wallis and Dunn tests (α = 0.05).

Results There was a significant decrease in immediate and 6-month BS for the A+SB and A+CSEB groups, which differed statistically from the C group. The fracture pattern was predominantly adhesive for SB and CSEB adhesive for C and A. The SEM images presented a different conditioning pattern of the dentin exposed to A.

Conclusion The dentin pretreatment with arginine interfered negatively in the immediate and long-term BS of the simplified adhesive system. However, the SBMP adhesive was not affected by arginine pretreatment presenting the most satisfactory results.

The Effect of the Application Sequence of Casein Phosphopeptide-Amorphous Calcium Phosphate Paste on the Shear Bond Strength of Etch-and-Rinse Resin Cements to Dentin

PURPOSE

To evaluate the effect of the application sequence of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (MI paste) on shear bond strength (SBS) of 2 etch-and-rinse resin cements to dentin.

MATERIALS AND METHODS

Sixty extracted human maxillary premolars were cut to expose the mid-coronal dentin surfaces. The teeth were randomly divided into 6 groups (n = 10), based on the resin cement used and CPP-ACP application. In groups 1-3, Excite DSC/Variolink II and in groups 2-4, One-Step Plus/Duolink was bonded to dentin. There were 3 groups for each cement as follows: with no treatment as a control; 3-minute application of CPP-ACP before acid etching (CPP-ACP/Etching); 3-minute application of CPP-ACP after acid etching (Etching/CPP-ACP). After storage in distilled water at 37°C for 24 hours, SBS test was performed. Data were analyzed with 2-way ANOVA and post-hoc Tukey test (α = 0.05).

RESULTS

CPP-ACP application on the dentin before and after acid etching significantly decreased the SBS of OS/Duolink (13.60 and 14.71 MPa, respectively vs. control; 21.21 MPa, p < 0.001); however, it did not influence the SBS of Excite DSC/Variolink II (25.14 MPa) before acid etching (27.37 MPa) or after acid etching (26.41 MPa, p > 0.388). The application sequence of CPP-ACP did not influence the SBS of etch-and-rinse resin cements evaluated.

CONCLUSION

CPP-ACP applications may lower the SBS in some etch-and-rinse resin cements, and timing of applications makes no difference.

Influence of the Extended Use of Desensitizing Toothpastes on Dentin Bonding, Microhardness and Roughness

The aim of this study was to evaluate the influence of an extended use of desensitizing toothpastes (DTs) on dentin bonding, microhardness and roughness. One hundred and twenty bovine incisor teeth were randomly divided into four groups: G1, distilled water (WATER); G2, Colgate Total 12 (CT12); G3, Colgate Sensitive Pro-Relief (CSPR); and G4, Sensodyne Repair ?αμπ; Protect (SRP). Dentin surfaces were etched with 17% EDTA and 2 years of simulated tooth brushing (20,000 cycles) was performed on their surfaces. Knoop microhardness, surface roughness and scanning electron microscopy (SEM) were performed before and after the simulated tooth brushing. For microshear bonding test, a 2-step self-etching adhesive system (Clearfil SE Bond) was used and 0.8 mm diameter composite resin (Filtek Z350 XT) cylinders were built. Microshear test was performed with an orthodontic wire and with a crosshead speed of 0.5 mm/min. The data were analyzed for: 1) bond strength (one-way ANOVA), 2) microhardness intra-group (Student's test) and inter-group (one-way ANOVA/Tukey's test) comparisons, 3) roughness intra-group (Student's test/Wilcoxon's test) and inter-group (Kruskal-Wallis/Student-Newman-Keuls test) comparisons. The extended use of both dentifrices (conventional and for sensitive teeth) did not affect the bond strength and produced a significant increase in microhardness and roughness of the dentin, except for the microhardness of the SRP group. The simulated tooth brushing technique with water produced an increase in roughness, without reducing significantly the dentin microhardness.

Effects of calcium-containing desensitizers on the bonding stability of an etch-and-rinse adhesive against long-term water storage and pH cycling

This study aimed to evaluate the effects of two calcium-containing desensitizing pastes on the bonding stability of an etch-and-rinse (E&R) adhesive to dentine. After dentine hypersensitivity model established, dentine surfaces were assigned one of the following pretreatment: Group 1, no desensitizer; Group 2, CPP-ACP; and Group 3, Novamin. Specimens were then bonded with an E&R adhesive. Beams from each tooth were randomly divided into three subgroups and then subjected to microtensile bond strength (MTBS) test after 24 h; 12 months of water storage; or 15 runs of pH cycling. Failure modes, nanoleakage, and tubule-occluding effectiveness were analyzed. Results showed that CPP-ACP- or Novamin-pretreated specimens mainly preserved the bonding strength after 12 months of water storage, while effective tubule occlusion could be observed. The results suggested that the calcium-containing desensitizers were compatible pretreatment for bonding with E&R adhesives to obtain reliable long-term bonding strength and prevention of post-operative sensitivity.

High-performance therapeutic quercetin-doped adhesive for adhesive-dentin interfaces

Almost half of dental restorations have failed in less than 10 years, and approximately 60% of practice time has been consumed to replace these dental restorations. As such, contemporary dentin adhesives should be modified to treat secondary caries and prevent the degradation of adhesive–dentin interfaces. To achieve this goal, we developed a versatile therapeutic adhesive in the present study by incorporating quercetin, which is a naturally derived plant extract, into a commercial adhesive at three concentrations (100, 500 and 1000 µg/mL). An unmodified adhesive served as a control. The antibacterial ability on Streptococcus mutans biofilm, conversion degree, microtensile bond strength, failure modes, in situ zymography, nanoleakage expression and cytotoxicity of quercetin-doped adhesive were comprehensively evaluated. Results showed that the quercetin-doped adhesive (500 µg/mL) preserved its bonding properties against collagenase ageing and inhibited the growth of S. mutans biofilm. Efficient bonding interface sealing ability, matrix metalloproteinase inhibition and acceptable biocompatibility were also achieved. Thus, a simple, safe and workable strategy was successfully developed to produce therapeutic adhesives for the extension of the service life of adhesive restorations.

Randomized clinical trial of the effect of NovaMin and CPP-ACPF in combination with dental bleaching

OBJECTIVE

This randomized, controlled, double-blind clinical study evaluated the effect of calcium sodium phosphosilicate (NovaMin) and casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF) on the prevention of post-operative sensitivity and on the effects of clinical bleaching treatment.

MATERIAL AND METHODS

Sixty volunteers were selected according to inclusion and exclusion criteria and were randomly assigned into three groups (n=20): CG (control group) patients, who were treated with 35% hydrogen peroxide; NOVAG (NovaMin group) patients, who were treated with 35% hydrogen peroxide followed by the application of NovaMin; and CPPG (CPP group) patients, who were treated with 35% hydrogen peroxide followed by the application of CPP-ACPF. Both bioactive agents were applied for five minutes. An evaporative stimulus associated with a modified visual scale was used to analyze sensitivity 24 hours after each bleaching session. The color evaluation was performed on the maxillary central incisors using a spectrophotometer. Associations between the intervention group, bleaching session, and reported sensitivity were tested using Chi-square partitioning.

RESULTS

Color change values (ΔE) were analyzed using analysis of variance (ANOVA). The significance level used for both tests was 5%. In the intragroup assessment, the Friedman test showed that only the CPP-ACPF group showed no statistically significant difference (p<0.05) between baseline and first bleaching session. In the intergroup assessment, the Kruskal-Wallis test showed that the CPPG had less postoperative sensitivity after the first session, when compared to the other groups (p<0.05). Color change analysis (ΔE) showed a significant difference between the means obtained in the different bleaching sessions in all groups (p<0.05).

CONCLUSIONS

This study showed that the combination of CPP-ACPF with 35% hydrogen peroxide significantly reduced post-operative sensitivity in the first session, compared with the other evaluated treatments. The association of CPP-ACPF and NovaMin did not affect the color change induced by tooth bleaching.

In Vitro Evaluation of Dentin Tubule Occlusion for Novel Calcium Lactate Phosphate (CLP) Paste

Introduction: The objective of this in vitro study is to evaluate the effective and long-term occlusion of dentinal tubules using a novel calcium lactate phosphate (CLP) based desensitizing agent. Methods: Dentin disks (n = 9) were pre-etched using 1 M lactic acid for 30 s and individually treated with Colgate^® Pro-Relief™ paste, CLP paste, and double distilled water (ddH₂O) by a rubber-cupped handpiece. Dentin disks were analyzed under optical micrographs for pre-treatment, directly after treatment, and 14 days post-treatment. One-way ANOVA and post-hoc Tukey’s test were used to determine whether there were any statistically significant differences in dentinal tubule diameter. Results: A significant decrease occurred in the mean tubule diameter for dentin disks treated with CLP paste. A decrease was observed from 3.52 ± 0.83 µm to 2.62 ± 0.42 µm right after treatment, further decreasing to 1.71 ± 0.45 µm after immersion in artificial saliva for 14 days (p < 0.05). Conclusions: The results suggest that the CLP based desensitizing paste has remineralization properties and provides instant and lasting effectiveness in dentinal tubule occlusion.

Effect of Desensitization Using Bioactive Glass, Hydroxyapatite, and Diode Laser on the Shear Bond Strength of Resin Composites Measured at Different Time Intervals: An In vitro Study

BACKGROUND

Dentin desensitizers may change the properties of smear layer and have adverse effects on the bonding performance of adhesive systems.

AIM

The aim of this study was to compare the effect of bioactive glass (BG), hydroxyapatite, and diode laser desensitization on shear bond strength of resin composites to dentin at different time intervals.

MATERIALS AND METHODS

Seventy-two caries-free maxillary premolars were selected. Buccal surfaces were flattened to expose dentin. Teeth were divided into four groups (Groups 1, 2, 3, and 4) according to treatment modality (control with no pretreatment, Sensodyne Repair and Protect, Teethmate Desensitizer, diode laser). Bonding was performed using self-etch adhesive followed by composite buildup. Universal testing machine was used to determine shear bond strengths immediately after bonding, after 3 months, and 5 months storage in artificial saliva.

RESULTS

Pretreatment with BG and hydroxyapatite desensitizers increased, whereas diode laser decreased mean shear bond strength of composite to dentin as compared to control group. No statistical significant difference in shear bond strength values was seen in groups after storage.

CONCLUSION

Desensitizing toothpastes incorporating remineralizing agents not only occluded open dentinal tubules but also increased shear bond strength of composite to dentin.

The Simultaneous Effect of Extended Etching Time and Casein Phosphopeptide-Amorphous Calcium Phosphate containing Paste Application on Shear Bond Strength of Etch-and-rinse Adhesive to Caries-affected Dentin

AIM

This study evaluated the simultaneous effect of extended etching time and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) containing paste application on shear bond strength (SBS) of etch-and-rinse adhesive to caries-affected-dentin (CAD).

MATERIALS AND METHODS

Fifty human third molars were used; 10 normal in group 1 and 40 caries-affected teeth in groups 2 to 5. In the CAD groups, teeth were randomly assigned into four groups (n = 10). In groups 2 and 4, phosphoric acid etching for 15 and 45 seconds was used and in groups 3 and 5, after 15 or 45 seconds etching respectively, CPP-ACP containing paste (MI paste) was applied for 3 minutes. After rinsing, single bond adhesive system and Z250 composite were used for resin composite build-up in all groups. After storage, SBS test was measured at cross head speed of 0.5 mm/min. Data were analyzed using one/two-way ANOVA and Tukey HSD test (α = 0.05).

RESULTS

Normal dentin groups showed the highest SBS among different groups. There was a statistically significant difference between different etching times in CAD groups (p < 0.05), but there were no significant differences between SBS of SB adhesive to CAD with or without CPP-ACP pretreated in both etching times. Most of the failure modes were adhesive except in groups 1 and 5 which cohesive failure in composite was also observed.

CONCLUSION

The results of our study indicated that extended etching time up to 45 seconds could enhance the SBS of CAD and approach nearly to SBS of normal dentin. Moreover, MI paste pretreatment had not significant effect on SBS of etch-and-rinse adhesive in CAD.

CLINICAL SIGNIFICANCE

Simultaneous application of extended etching time and CPP-ACP containing paste may be a suggested method in increasing the SBS of adhesive to CAD.