Push-out bond strength of MTA with antiwashout gel or resins

In vitro and in vivo evaluation of iRoot BP Plus as a coronal sealing material for regenerative endodontic procedures

OBJECTIVES

To investigate in vitro effects of a nanoparticle bioceramic material, iRoot BP Plus, on stem cells from apical papilla (SCAP) and in vivo capacity to induce pulp-dentin complex formation.

MATERIALS AND METHODS

The sealing ability of iRoot BP Plus was measured via scanning electron microscopy (SEM). SCAP were isolated and treated in vitro by iRoot BP Plus conditioned medium, with mineral trioxide aggregate (MTA) conditioned medium and regular medium used as controls, respectively. Cell proliferation was assessed by BrdU labeling and MTT assay and cell migration was evaluated with wound healing and transwell assays. Osteo/odontogenic potential was evaluated by Alizarin red S staining and qPCR. Pulp-dentin complex formation in vivo was assessed by a tooth slice subcutaneous implantation model.

RESULTS

iRoot BP Plus was more tightly bonded with the dentin. There was no difference in SCAP proliferation between iRoot BP Plus and control groups (P > 0.05). iRoot BP Plus had a greater capacity to elevated cell migration (P < 0.05) and osteo/odontogenic marker expression and mineralization nodule formation of SCAP compared with MTA groups (P < 0.05). Furthermore, the new continuous dentine layer and pulp-like tissue was observed in the iRoot BP Plus group in vivo.

CONCLUSIONS

iRoot BP Plus showed excellent sealing ability, promoted the migration and osteo/odontogenesis of SCAP and induced pulp-dentin complex formation without affecting the cell proliferation, which indicated iRoot BP Plus was a promising coronal sealing material in REPs.

CLINICAL RELEVANCE

The coronal sealing materials play crucial roles for the outcomes of REPs. This study showed that iRoot BP Plus has good coronal sealing and promote pulp-dentin complex formation compared with MTA, providing experimental evidences for the clinical application of iRoot BP Plus as a promising coronal seal material in REPs.

Kan kontaminasyonunun farklı kök ucu dolgu materyallerinin dentine bağlanma dayanımına etkisi

Amaç: Bu in vitro çalışmanın amacı, kan kontaminasyonunun farklı kök ucu dolgu materyallerinin dentine bağlanma dayanımına etkisinin değerlendirilmesiydi. Gereç ve Yöntem: Bu çalışmada tek köklü 90 adet maksiler santral diş kullanıldı. Dişlere endodontik tedavi uygulandıktan sonra kök uçları rezeke edildi ve kök ucu kaviteleri hazırlandı. Öncelikle örnekler, kavitelerin kanla kontaminasyonuna göre (+/-) 2 gruba ayrıldı. Daha sonra kök ucu dolgu malzemelerine göre üç alt gruba ayrıldı: MTA Repair HP, RetroMTA, MTA Flow (n=15). Bu malzemeler üreticinin talimatları doğrultusunda kaviteye yerleştirildi. Örnekler 21 gün boyunca 37 °C’de %100 nemli ortamda bekletildi. 1.0±0.1 mm kesitler elde edildikten sonra itme-bağlanma dayanımı testi gerçekleştirildi. Başarısızlık tipini değerlendirmek için her kesit stereomikroskop altında incelendi. Veriler tek yönlü varyans analizi ve bağımsız örneklem t-testi kullanılarak analiz edildi. Bulgular: Bağlanma dayanımı, kan kontaminasyonunun varlığından önemli ölçüde olumsuz yönde etkilendi (p&lt;0.05). En yüksek bağlanma dayanımı MTA Flow (-) grubunda, en düşük bağlanma dayanımı ise MTA Repair HP (+) grubunda gözlendi (p&lt;0.05). Hem kanla kontamine olan grupta hem de kanla kontamine olmayan grupta MTA Repair HP en düşük bağlanma dayanımını gösterirken (p&lt;0.001), MTA Flow ve RetroMTA arasında anlamlı farklılık bulunmadı (p&gt;0.05). Sonuç: Kan kontaminasyonu dentine bağlanma dayanımını azalttı. Materyaller arasında en yüksek bağlanma dayanımını MTA Flow gösterdi.

Effect of different dentin moisture on the push-out strength of bioceramic root canal sealer

Background/purpose

Different moisture condition may affect the adhesion between obturation materials and root canal walls, thus further affect the quality of root canal obturation. The aim of this study was to evaluate the influence of dentin moisture conditions after different root canal drying protocols on the push-out strength of bioceramic root canal sealer.

Materials and methods

Twenty root canals from extracted human decoronated premolars were prepared in vitro to #30/0.09 taper and assigned to 4 moisture condition groups after using different root canal drying protocols: normal moisture (paper point) group: the canals were blot dried with paper points until the last one appeared dry. Ethanol dry group: the canals were dried with paper points followed by dehydration with 95% ethanol. Isopropanol dry group: the canals were dried with paper points followed by dehydration with 70% isopropanol. Complete dry group: the canals were dried in an air-blowing thermostatic oven for at least 6 h until there was no change in weight at an interval of 1 h. After drying, the canals were obturated with bioceramic sealer iRoot SP. Then, each root was sectioned into eight slices with 1-mm-thick using a diamond saw (40 slices each group). The push-out strength was tested for each slice between the sealer and dentin wall using a universal testing machine at a crosshead speed of 0.5 mm/min, and failure modes were recorded. Two-way analysis of variance and Tukey test were used to analyze the push-out strength. Logarithmic linear regression analysis was used to compare the failure modes.

Results

Push-out strength was statistically different in different moisture groups (P < 0.05). After drying using paper point, iRoot SP specimens showed the highest push-out strength (2.04 ± 0.03 MPa), followed by 95% ethanol, 70% isopropanol. The lowest push-out strength (0.68 ± 0.04 MPa) was observed under complete dry. For the failure modes, the majority were cohesive failures in the coronal and middle thirds of the root; while in the apical third, mixed failure was common.

Conclusion

Different drying protocols influenced the push-out strength between bioceramic sealer and canal wall.

Dislodgement pushout resistance of five bioceramic root-end filling materials

This study evaluated the dislodgement push-out resistance of five bioceramic materials. One hundred single-rooted teeth with one canal had the apical 3 mm and crown resected to create a 14 mm standardized length. The canals were instrumented to an apical size 80 with a 3 mm root-end preparation made with ultrasonic diamonds. The prepared roots were randomly divided into 5 root-end restorative groups (n=20). ProRoot MTA, Biodentine, EndoSequence Root Repair Material, EndoSequence Fast Set Putty, and EndoSequence BC Sealer with each material placed following manufacturer's instructions and stored at 100% humidity for 2 weeks. An apical-to-coronal static testing load with the identified dislodgement force converted into MPa with mean results analyzed with Kruskal-Wallis and Dunn's post hoc tests (α=0.05). ProRoot MTA and Biodentine displayed similar push-out stress resistance and exhibited significantly greater stress resistance than the similar Endosequence materials. However, all materials failed cohesively and were not dislodged from the root canal surface.

The effect of different chelators on the dislodgement resistance of MTA Repair HP, MTA Angelus, and MTA Flow

The aim of this study was to investigate the influence of various irrigants on the dislodgement resistance of MTA Repair HP, MTA Angelus, and MTA Flow to root dentin. Three slices (1.0 ± 0.1 mm) were prepared from the middle third of 20 human maxillary anterior teeth. On each dentin disc, three perpendicular simulated perforation holes with a standardized 0.8 mm diameter were created. The sections from the same root were distributed arbitrarily into three groups (n = 20) for smear layer removal procedure: ethylenediaminetetraacetic acid (EDTA), chitosan-based silver nanoparticles (AgNPs-chitosan), and maleic acid (MA). Afterwards, the holes were randomly filled with one of the three investigated cements. The samples were submitted to the push-out test using a universal measuring system. Kruskal-Wallis and Mann-Whitney U tests were used to assess statistical differences among the groups. When the results were evaluated, it was found that the types of cement and chelating agents significantly affected the dislocation resistance (P < 0.05). EDTA provided a higher dislocation resistance with the investigated cements in comparison to MA and AgNPs-chitosan (P < 0.05). Furthermore, it was observed that MTA Flow and MTA Angelus presented improved dislocation resistance values than the MTA Repair HP when used with EDTA (P < 0.05). The findings indicated that EDTA increased the dislodgement resistance of the investigated cements. In conclusion, when EDTA used, MTA Flow, and MTA Angelus showed higher dislocation resistance values.

Does Delayed Restoration Improve Shear Bond Strength of Different Restorative Protocols to Calcium Silicate-Based Cements?

The purpose of the present study was to assess the proper time to perform a restoration (immediately or delayed) after placement of two calcium silicate-based cements (CSCs) and to test the performance of two different restorative protocols regarding shear bond strength (SBS). Seventy-five acrylic blocks were randomly divided into five groups (n = 15). Specimens were filled with either ProRoot MTA (Dentsply Tulsa Dental) or Biodentine (Septodont). The restoration was performed at an immediate (12 min) or delayed (seven days) timeframe, using a resin-based flowable composite (SDR) (bonded to the CSC using a universal bonding system) or glass ionomer cement (GIC) as restorative materials. SBS was measured using a universal testing machine. Fractured surfaces were evaluated, and the pattern was registered. Statistical analysis was performed using the Dunn–Sidak post hoc test (P < 0.05). Biodentine/immediate SDR showed the highest mean SBS value (4.44 MPa), with statistically significant differences when compared to mineral trioxide aggregate (MTA)/GIC (1.14 MPa) and MTA/immediate SDR (1.33 MPa). MTA/GIC and MTA/immediate SDR did not present significant differences regarding SBS. No statistical differences were verified concerning mean SBS between both CSCs within the 7 day groups. MTA/delayed SDR (3.86 MPa) presented statistical differences compared to MTA/immediate SDR, whereas no differences were observed regarding Biodentine performance (Biodentine/immediate SDR and Biodentine/delayed SDR (3.09 MPa)). Bonding procedures directly on top of MTA might be preferably performed at a delayed timeframe, whereas Biodentine might allow for immediate restoration.

Design Variability of the Push-out Bond Test in Endodontic Research: A Systematic Review

INTRODUCTION

There is limited literature on the impact of testing variables on the push-out bond test (POBT). This review identified designs of the POBT used in the endodontic literature and aimed to determine which experimental variables may influence the push-out bond strength (POBS).

METHODS

A systematic review based on PRISMA guidelines was performed by searching the PubMed, SCOPUS, and Cochrane library databases using terms including push-out and dislocation resistance and descriptions of endodontic materials. Test variables assessed included method of root preparation, timing of sectioning compared with filling, thickness, diameter and taper of sections, and plunger size and velocity. The POBS of 3 common materials (gutta-percha and AH Plus, mineral trioxide aggregate, and Biodentine) were collected from investigations, and a comparison was attempted.

RESULTS

One hundred thirty-three studies assessed the POBS of root-filling materials, 68 assessed root repair cements/root-end filling materials, and 16 assessed orifice barrier materials other than mineral trioxide aggregate. There was significant variation in all of the assessed variables, resulting in a large range of reported values for the POBS of the various materials. Because of this heterogeneity in study design, no further statistical analysis of the impact of the test variables on POBS was possible.

CONCLUSIONS

There was considerable variation in the POBT design used in endodontic research. Greater standardization is required for future research as well as accurate reporting for all test variables to assess the impact of specific design variables on POBS.

Effect of Smear Clear and Some Other Commonly Used Irrigants on dislodgement resistance of Mineral Trioxide Aggregate to Root Dentin

Background

This study aimed to assess the push-out bond strength of mineral trioxide aggregate (MTA) to root canal dentin after irrigation with Smear Clear in comparison with 2.5% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) and saline as commonly used root canal irrigants.

Material and Methods

The coronal and mid-root areas of maxillary anterior teeth were horizontally sectioned into one-millimeter thick slices. The root canal lumen of dentinal slices was dilated using a diamond bur with 1.3 mm diameter. After the application of MTA, the samples were incubated in 100% humidity for 10 minutes and were then randomly divided into four groups (n=20) and immersed in Smear Clear, 2.5% NaOCl, 2% CHX and saline for 30 minutes. No irrigant was used for the control group (n=20). A wet cotton pellet was placed on the samples and after 48 hours of incubation, push-out bond strength was measured using a universal testing machine. The samples were evaluated under a stereomicroscope to determine the mode of failure. One-way ANOVA was used to assess statistical differences among the groups.

Results

The control group showed the highest bond strength with significant differences with other groups (P<0.05). Among the experimental groups, the saline group had no significant difference with CHX (P=0.09) but it had significant differences with Smear Clear and NaOCl groups (P<0.05). No significant difference in bond strength to MTA was noted after irrigation with Smear Clear, CHX and NaOCl (P>0.05). Other pairwise comparisons showed no significant difference (P>0.05).

Conclusions

Irrigation with Smear Clear, CHX and NaOCl did not cause a significant change in bond strength of MTA to dentin.

Key words:Root Canal Irrigants, push-out, Mineral Trioxide Aggregate, dentin.

The effect of obturation technique on the push-out bond strength of calcium silicate sealers

INTRODUCTION

Calcium silicate-based sealers are known to have excellent sealing ability and bioactivities. They are typically recommended to be used in a single-cone (SC) technique. No studies have evaluated the effects of the thermoplastic obturation technique on the dentin interface of these sealers. The purpose of this study was to evaluate the push-out bond strengths of MTA Plus Sealer (Avalon Biomed Inc, Bradenton, FL) and EndoSequence BC Sealer (BC; Brasseler USA, Savannah, GA) when they were used in a thermoplastic technique.

METHODS

Fifty single-rooted human extracted teeth were randomly divided into 5 groups (n = 10), instrumented, and obturated with the SC technique or continuous wave (CW) technique: group 1, BC-SC; group 2, BC-CW; group 3, MTA Plus-SC; group 4, MTA Plus-CW; and group 5, AH Plus (Dentsply DeTrey, Konstanz, Germany)-CW. The roots were sectioned into 1.0-mm-thick slices, and bond strengths were measured using a standardized push-out test. The mode of failure was determined by visual inspection under magnification.

RESULTS

The MTA Plus-CW had statistically significant lower bond strengths than all other groups. The BC-SC group had statistically higher bond strengths than the MTA Plus-SC and AH Plus-CW groups. No significant differences were seen among the other groups. Modes of failure were predominately cohesive or mixed except for group 4 (ie, MTA Plus-CW) in which nearly half the specimens had no visible sealer.

CONCLUSIONS

BC and MTA Plus sealer showed favorable bond strengths when used in an SC technique. The CW obturation technique decreased the bond strengths of these sealers.

Mercury intrusion porosimetry and assessment of cement-dentin interface of anti-washout-type mineral trioxide aggregate

INTRODUCTION

One of the disadvantages of mineral trioxide aggregate (MTA) is washout (ie, the tendency of freshly prepared cement paste to disintegrate upon early contact with physiological fluids). A novel MTA (MTA Plus; Prevest Denpro, Jammu City, India) exhibits low washout and superior physical properties when mixed with a gel instead of water. When used as a root-end filler, MTA is in contact with both bone and root dentin. This study aimed to investigate the porosity and interfacial characteristics of the novel MTA mixed with water or antiwashout gel.

METHODS

Porosity was evaluated after 1 or 28 days of immersion in Hank's balanced salt solution using mercury intrusion porosimetry. The root dentin to material interface was investigated using a scanning electron microscope and energy-dispersive X-ray spectroscopy complete with line scans and elemental maps.

RESULTS

Anti-washout-type MTA Plus was found to have lower initial porosity than MTA Plus mixed with water although this trend was reversed after 28 days of immersion in physiological fluid. Both materials exhibited good marginal adaptation. The diffusion of silicon, calcium, and phosphorus across the cement/dentin interface was observed.

CONCLUSIONS

MTA Plus mixed with antiwashout gel was found to have lower initial porosity than MTA Plus mixed with water. Both materials exhibited good marginal adaptation and the diffusion of silicon, calcium, and phosphorous across the cement/dentin interface. Thus, the anti-washout-type MTA can be considered to be a suitable substitute for ordinary MTA in all its indications.