Properties of a novel polysiloxane-guttapercha calcium silicate-bioglass-containing root canal sealer

Impact of LASER activated irrigation on the retrievability of Guttaflow bioseal (in-vitro study)

BACKGROUND

This study aimed to evaluate the efficiency of diode LASER activated irrigation in the removal of GuttaFlow Bioseal root canal filling material during retreatment.

MATERIALS AND SUBJECTS

Root canals of forty-five single-rooted human mandibular premolar teeth were prepared with ProTaper Universal rotary system and obturated with lateral condensation obturation technique using Gutta Percha and Roeko GuttaFlow Bioseal root canal sealer. All specimens were retreated with ProTaper Universal Retreatment System files then divided to three different groups according to the technique of activation of irrigation. Samples were sectioned, and the residual filling remnants were captured using digital camera attached to microscope. Data was collected by three different interpreters, to eliminate the subjectivity of the process, using the ImageJ Software. The mean value of the data was obtained and evaluated statistically. The significance level was set at P ≤ 0.05.

RESULTS

The remaining filling materials in the canals irrigated with ultrasonic activation (6.17 ± 1.42 at coronal level, 10.93 ± 1.91at middle level, and 14.58 ± 2.23 at apical level) were less than these irrigated with LASER activation (15.87 ± 3.78 at coronal level, 21.28 ± 4.44 at middle level, and 27.06 ± 2.68 at apical level). Maximum amount of remaining filling materials was present in the canals irrigated with passive side-vented syringe (23.07 ± 3.22 at coronal level, 38.09 ± 7.27 at middle level, and 34.24 ± 9.77 at apical level).

CONCLUSION

The activation of irrigation techniques used were incapable of complete removal of filling material at root canal walls.

A Literature Review of the Effect of Heat on the Physical-Chemical Properties of Calcium Silicate-Based Sealers

INTRODUCTION

Recently, calcium silicate-based sealers (CSSs) have gained popularity in endodontic practice due to their biocompatibility and antimicrobial properties. They are considered viable alternatives to epoxy resin-based sealers. With the increased use of CSSs and warm vertical compaction techniques in root canal treatment, evaluating the impact of heat on CSSs properties is essential, therefore this review aimed to present a qualitative synthesis of available in vitro studies assessing the impact of heat on the physical-chemical properties of CSSs.

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 guidelines, a systematic advanced electronic search was performed in Scopus, Embase, Medline (via PubMed), Web of Science, and Cochrane databases in November 2023 and updated in April 2024. In vitro studies that evaluated the physical-chemical properties of CSSs were eligible. PRILE 2021 guidelines were used for the assessment of the risk of bias-included studies.

RESULTS

The search identified a total of 6421 preliminary results and 10 studies were included for qualitative assessment. Eleven different physiochemical properties were assessed by the included studies. Setting time and flow were the most evaluated property among the studies. A qualitative synthesis of the evidence on each property is presented.

CONCLUSIONS

Based on the in vitro studies assessed in the present systematic review, results reveal that exposing CSSs to heat can accelerate their setting time, reduce their flow, and increase their film thickness. Concerns persist regarding solubility, viscosity, radiopacity, dimensional change, microhardness, porosity, and compressive strength, requiring further research. Certain CSSs, such as MTA Fillapex and Endosequence BC sealer HiFlow, show minimal changes under heat, making them potential candidates for warm filling techniques.

Field Emission Scanning Electron Microscope Analysis of the Marginal Adaptation of Various Root Canal Sealers at the Dentin-Sealer and Sealer-Guttapercha Interfaces at Three Root Canal Levels: An In Vitro Study

Aims An in vitro evaluation of the marginal adaptation of four root canal sealer variants at the dentin-sealer and sealer gutta-percha interfaces in the coronal, middle, and apical thirds of root canals was conducted using field emission scanning electron microscope (FESEM) analysis.  Materials and methods In total, 80 extracted human mandibular premolar teeth were used in this study. All teeth were decoronated to standardize the root length to 14 mm. A round bur was used to gain access into canal orifices and the working length was determined. Root canal instrumentation was performed using the crown-down technique with ProTaper Next rotary files up to size X3, along with the use of root canal irrigants. All specimens were then randomly divided into four groups, with 20 specimens per group, depending on the root canal sealer used: Group A consisted of AH Plus (Dentsply Maillefer, Ballaigues, Switzerland), Group B of MTA-Fillapex (Angelus Dental, Londrina, Brazil), Group C of Bio-C Sealer (Angelus Dental), and Group D of GuttaFlow-2 (Coltene Whaledent, Altstatten, Switzerland). All specimens were obturated with size X3 gutta-percha points uniformly coated with respective sealers in the single-cone technique and coronal access was sealed with glass ionomer cement. The specimens were incubated for seven days and then horizontally sectioned at the coronal, middle, and apical thirds of the root canals. On each sample obtained, three points were randomly chosen and both sealer-dentin and sealer gutta-percha interfaces were examined under FESEM at 1000x magnification. The marginal gaps of all four sealers at both interfaces and at three levels of root canals were measured in µm and values were recorded, tabulated, and used for data analysis. One-way analysis of variance (ANOVA) and post hoc Bonferroni tests were used for statistical analysis. A p-value ≤ 0.05 was considered statistically significant. Results Compared to the sealer gutta-percha interface, AH Plus, MTA-Fillapex, and Bio-C sealers at all three levels of the root canals showed more marginal gaps at the sealer-dentin interface with a significant difference (p<0.05). However, the GuttaFlow-2 sealer showed no significant difference (P > 0.05).  Conclusions The marginal adaptation of the GuttaFlow-2 sealer is superior to both dentin and gutta-percha at the coronal, middle, and apical thirds of root canals compared to other sealers used in the study.

Assessment of different irrigation techniques on the penetration depth of different sealers into dentinal tubules by confocal laser scanning microscope: An in vitro comparative study

Background

The effective disinfection of the entire root canal system aids in the penetration of irrigants into the dentinal tubules further improving sealer penetration and achieving a three-dimensional seal in endodontically treated teeth. Various final irrigation techniques can be employed to achieve this goal. Therefore, this study intended to assess and compare the efficacy of three final irrigation techniques on the depth of penetration of two root canal sealers into dentinal tubules using confocal laser scanning microscope (CLSM).

Methods

Forty-eight single-rooted mandibular premolars were selected and decoronated to a length of 12 mm. All the samples were prepared using ProTaper Gold rotary files and divided into three groups: Group 1 - Conventional syringe irrigation (CSI), Group 2 - passive ultrasonic irrigation (PUI), and Group 3 - Pro-agitator tip system (PATS). Each group was divided into two subgroups: Subgroup A - AH Plus and Subgroup B - GuttaFlow Bioseal (GFB). Then, sealers were mixed with 0.1% rhodamine B dye and the samples were obturated. All the samples were sectioned at 2 mm and 5 mm from the apex and visualized under confocal laser scanning microscope (CLSM) (10×) for maximum mean penetration depth and percentage of sealer penetration. Statistical analysis was done using the independent t-test and one-way analysis of variance test, followed by Tukey's Post hoc analysis.

Results

PUI performed better in the apical third, whereas PUI and PATS showed comparable results in the middle third for both depth and percentage of sealer penetration. Among the two sealers, GFB performed better than AH Plus in both the apical and middle third. These values were statistically significant. (P < 0.05).

Conclusion

Final irrigation activation with PUI or PATS can significantly improve sealer penetration. The average depth of penetration of GFB both at the middle and apical third of the root was significantly superior to AH Plus.

Dentinal tubule penetration following ultrasonic, sonic, and single-cone technique of a biosealer: An ex vivo study

Background

The endodontic space is complex, and using a single-cone obturation technique fails to ensure a complete filling.

Introduction

This study aimed to investigate the effect of ultrasonic activation, sonic activation, and single-cone technique of a biosealer on its dentinal tubular penetration.

Materials and Methods

In the experiment, single-root mandibular premolars were randomly assigned to three groups (n = 20): group A, ultrasonic activation; Group B, sonic activation; and Group C, single-cone technique. Penetration of the fluorescently labeled biosealer was investigated using a confocal laser scanning microscope.

Results

The data were statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (P = 0.05). The highest penetration of biosealer was observed in Group A, followed by Group B (P < 0.05).

Conclusions

Dentinal tubule penetration of biosealer was significantly improved by ultrasonic and sonic activation techniques.

The Effect of Different Obturation Techniques Using Different Root Canal Sealers on the Residual Filling Material After Retreatment Procedures

BACKGROUND

This study aimed to compare the effect of different obturation techniques with root canal sealers on the residual filling material after retreatment using SEM.

MATERIAL AND METHOD

Sixty (60) single rooted mandibular premolars were selected and instrumented with rotary files using the Mtwo system up to file size 30/.05 taper. The samples were randomly divided to two groups based on the type of sealer and three sub-groups (n=10) based on the obturating technique used. The root fillings were removed using the PTUR system files and the specimens were longitudinally sectioned while digital images were obtained from the root canals with SEM. The time required to reach working lenght were recorded.

RESULTS

There was no difference in terms of the smear score when comparing both sealer and obturation technique groups in the apical third. Smear scores were significantly affected by the type of sealer and obturation technique in the medium and coronal thirds of root canals (p<0.05). Higher smear scores were obtained with GFB than AH Plus (p<0.05). The time required to reach working length with GFB was longer than AH Plus (p<0.05).

CONCLUSION

Residual filling material was observed in all samples, regardless of the root canal sealer or the obturation technique used. There was a significantly lower smear scores in the AH Plus groups as compared to the GFB.

Remineralization ability of different root canal sealers

Aims

This research was designed to contrast the biocompatibility and remineralization ability of different sealers (BioRoot, MTA-FillApex and GuttaFlow-Bioseal).

Method

Twenty rabbits were used in this study, they were randomly divided into 4 groups equally depending on the observation time"3,7,14, and 28 days" post-implantation. Each rabbit was generally anesthetized,"7cm"long incision was made on the skin of the right and left sides of the ventral aspect of the mandible of each rabbit, 4 bony cavities of approximately"5mm"in depth and"2mm"in diameter (2 cavities on the left side and 2 cavities on the right side of mandible of each rabbit) were made in the cortical surface of the buccal alveolar bone. The sealers mixed depend on manufactural instructions and immediately insert into the prepared cavities (in the right side the BioRoot and MTA-FillApex were placed while on the left side, GuttaFlow-Bioseal was placed in one cavity and the other cavity was left unfilled as control).The same volume of each sealer was placed in the corresponding cavity using disposable syringes. After each observation period, the animals were sacrificed and bone biopsy from the tested area was taken and examined histologically using Olympus light microscopy at"400X"magnification.

Results

The obtained data were analyzed through non-parametric statistical tests using SPSS software version"22".Kruskal-Wallis test and Mann - Whitney test were utilized at"0.05"levels of significance to evaluate the results. GuttaFlow-Bioseal displayed excellent biocompatibility in comparison to other groups indicated by low inflammatory tissue reaction at all evaluation intervals. While the BioRoot group represented better osteo-conductivity although statistically not significant than GuttaFlow-Bioseal group.

Conclusion

BioRoot and GuttaFlow-Bioseal showed higher osteo-conductivity and biocompatibility than MTA-FillApex. However, all sealer used in this study were well tolerated by bone tissue and might accelerate bone repair.

Effect of silicone-based sealers on fiber post retention: An in vitro study

PURPOSE

The effect of a silicone-based sealer on fiber post retention has not been the subject of research and remains unclear. This study aimed to evaluate and compare the impact of a silicone-based sealer and an epoxy resin sealer on fiber post retention.

MATERIAL AND METHODS

Forty extracted human mandibular premolars that were caries-free, single-rooted, and possessed straight single canals were the specimens of the present study. Teeth were randomly divided into two groups (n = 20 each). All specimens were prepared using gutta-percha. The sealer used in the first group was Guttaflow 2, while AH26 was used in the second group. Post spaces were prepared immediately after obturation for each specimen. Prefabricated fiber posts were luted in both groups using a self-adhesive resin cement (RelyX-U200). Each specimen was vertically secured using a universal testing machine (Instron Corp.) and a constant pull-out force at a loading rate of 0.5 mm/min was applied until the point of dislodgement. Data were analyzed using t-tests.

RESULTS

A significant difference was found between the mean of maximum loads of the silicone-based sealer and epoxy resin sealer groups (p = 0.0001). The mean maximum load for the epoxy resin sealer group was 194.62 N, while that for the silicone-based sealer group was 111.64 N.

CONCLUSION

Fiber post retention in teeth obturated using silicone-based sealer was inferior to that in teeth obturated with epoxy resin sealer. Therefore, the sealer used during obturation can significantly affect fiber post retention.

Guttapercha Improves In Vitro Bioactivity and Dentin Remineralization Ability of a Bioglass Containing Polydimethylsiloxane-Based Root Canal Sealer

Guttapercha (GP, trans-1,4-polyisoprene) is the most used tooth root filling material, and it must be used with an appropriate cement (typically a polydimethylsiloxane (PDMS)-based sealer) to ensure an adequate canal obturation. This study aimed to assess the bioactivity and dentin remineralization ability of a bioglass containing PDMS commercial endodontic sealer, BG-PDMS (GuttaFlow Bioseal), and to evaluate the possible influence of a GP cone (Roeko GP point) on the mineralization process. To this end, BG-PDMS disks were aged alone or in the presence of a GP cone in Hank's Balanced Salt Solution (28 d, 37 °C). Dentin remineralization experiments were carried out under the same conditions. Micro-Raman and IR analyses demonstrated that BG-PDMS is bioactive, thanks to the formation of a silica-rich layer with nucleation sites for B-type carbonated apatite deposition. This phase was thicker when BG-PDMS was aged in the presence of GP. The two materials influenced each other because GP, which alone did not show any bioactivity, nucleated a calcium phosphate phase under these conditions. Analogously, dentin remineralization experiments showed that BG-PDMS is able to remineralize dentin, especially in the presence of GP. Under the experimental conditions, GP acted as a templating agent for calcium phosphate deposition.

Antibacterial and physical properties of resin cements containing MgO nanoparticles

Cariogenic bacteria and dental plaque biofilm at prosthesis margins are considered a primary risk factor for failed restorations. Resin cement containing antibacterial agents can be beneficial in controlling bacteria and biofilm. This work aimed to evaluate the impact of incorporating magnesium oxide nanoparticles (MgONPs) as an antibacterial filler into dual-cure resin cement on bacteriostatic activity and physical properties, including mechanical, bonding, and physicochemical properties, as well as performance when subjected to a 5000-times thermocycling regimen. Experimental resin cements containing MgONPs of different mass fractions (0, 2.5%, 5%, 7.5% and 10%) were developed. Results suggested that the inclusion of MgONPs markedly improved the materials' bacteriostatic effect against Streptococcus mutans without compromising the physical properties when its addition reached 7.5 wt%. The mechanical properties of the specimens did not significantly decline after undergoing aging treatment, except for the flexural properties. In addition, the cements displayed good bonding performance and the material itself was not prone to cohesive fracture in the failure mode analysis. Furthermore, MgONPs possibly have played a role in decelerating material aging during thermocycling and enhancing bonding fastness in the early stage of cementation, which requires further investigation. Overall, developing MgONPs-doped resin cements can be a promising strategy to improve the material's performance in inhibiting cariogenic bacteria at restoration margins, in order to achieve a reduction in biofilm-associated secondary caries and a prolonged restoration lifespan.

Dimensional changes of endodontic sealers-An in vitro model simulating a clinical extrusion scenario during 18 months

OBJECTIVES

To examine the dimensional changes of endodontic sealers during 18 months using three-dimensional (3D) surface scanning and subtraction radiography in a novel in vitro sealer-extrusion model.

MATERIAL AND METHODS

Fifty endodontically instrumented acrylic teeth were randomly allocated to five groups (n = 10) filled with Apexit Plus, AH Plus, BioRoot RCS, TubliSeal EWT, and gutta-percha (control). Freshly mixed sealers were intentionally extruded during obturation. All teeth were immersed in a physiologic solution for up to 18 months. Blinded 3D surface scans (resolution: ~10 μm) and digital radiographs of the teeth were obtained at baseline (immediately after obturation); and then after 1 week, and at 1, 3, and 18 months. For blinded assessment of sealer dimensional change, 3D models and radiographs were superimposed using specific software. Volumetric differences, root mean square (RMS), and area change from subtraction radiography measured at each period within each sealer group were thereafter calculated. Repeated measures analyses were done with Bonferroni adjustment for multiple comparisons; standard errors, p values, and 95% confidence intervals (CI) were reported.

RESULTS

Analyses of the volumetric data confirmed significant, progressive material loss for Apexit Plus when compared to the other investigated sealers or the control group (p ≤ 0.02). Immersion period significantly influenced the volumetric dimensional changes of Apexit Plus already after 1 month (p < 0.01). For TubliSeal EW, the effect of the immersion period on the dimensional changes was noted after immersion for 3 months (p ≤ 0.02), while for BioRoot RCS this was evident only at 18 months (p < 0.01). Same trends were noted for the RMS data, whereas progressive dimensional changes using subtraction radiography only revealed significant changes for Apexit Plus (p = 0.01).

CONCLUSIONS

The largest dimensional changes were shown by Apexit Plus, followed by Tubliseal EWT and BioRoot RCS. AH Plus remained stable throughout 18 months.

Effect of nanosized bioactive glass addition on some physical properties of biodentine

The aim of this in vitro study was to investigate some physical properties of Biodentine (BD) (Septodont, France) that has been modified by adding nanosized bioactive glass (nBG) particles to it in different ratios. The cement was modified by adding 1% (7 mg) and 2% (14 mg) nBG powder to BD. BD was used as the control group in its commercial form. A total of 240 cement samples (n = 80) were prepared according to the standard measurements for each test. Subsequently, tests to determine compressive strength, microhardness, initial setting time, and solubility of the samples were performed. The obtained data were statistically analyzed using one-way ANOVA and Tukey's HDS tests, and the significance level was found to be 0.05. The compressive strength values of the samples modified with 1% and 2% nBG were higher than those of the unmodified BD; however, no statistically significant difference was found between them [BD + nBG (2 wt%) ⩾ BD+nBG (1 wt%) ⩾ control BD], (p > 0.05). The microhardness values of the samples modified with 1% and 2% nBG were found to be significantly higher than those of the control group [BD + nBG (2 wt%) > BD+nBG (1 wt%) > control BD], p < 0.05. Initial setting times were determined as 14 min for unmodified BD, 13 min for BD + nBG (1 wt%), and 12 min for BD + nBG (2 wt%). The addition of nBG to BD significantly reduced the initial setting time of BD (p < 0.05). A significant decrease was observed in the solubility of the BD modified with nBG samples compared to that of the control group [control BD > BD+nBG (1 wt%) >BD+nBG (2 wt%)], p < 0.05. Within the limitations of this study, it was found that the addition of certain amounts of nBG to BD positively affected some physical properties of the cement. Future in vitro and in vivo studies should be performed to prove the clinical applicability of the cements used in this study.

Effect of using calcium-silicate and silicone based root canal sealers in bulk or with main core material on bond strength

Background

The purpose of this study was to assess the push-out bond strength of calcium-silicate and silicone based root canal sealers in bulk and with main cone.

Methods

Roots (n=48) randomly divided into 4 groups (n=12) according to the obturation protocol; (1) iRoot SP in bulk; (2) iRoot SP with gutta-percha; (3) GuttaFlow Bioseal in bulk; (4) GuttaFlow Bioseal with gutta-percha. Six horizontal sections were obtained from each root (n=72). Effect of sealers on bond strength was statistically significant (P<0.05).

Results

Highest mean value was obtained in iRoot-Bulk group and lowest in GuttaFlow Bioseal-GP group. Both iRoot SP groups had significantly higher bond strength values than both GuttaFlow Bioseal groups (P<0.05). There was no significant difference between iRoot-GP and iRoot-Bulk groups (P=0.603) also GuttaFlow Bioseal-GP and GuttaFlow Bioseal-Bulk groups (P=0.684).

Conclusion

Based on findings, using calcium silicate-based sealer in bulk can be also suitable in clinical practice.

Evaluation of the root filling quality with experimental carrier-based obturators: a CLSM and FEG-SEM analysis

This study evaluated tubule penetration of GuttaFlow Bioseal with cold single cone or carrier-based technique, under confocal laser scanning microscopy (CLSM). Twenty straight single-rooted teeth were instrumented with Hyflex CM and divided in two groups (n = 10) according to the obturation method: single cold gutta-percha cones; experimental carrier-based obturators. GuttaFlow Bioseal, labelled with Rhodamine B dye, was used as sealer in both groups. Teeth transversally sectioned were observed under CLSM. Percentage of sealer penetration and integrity of sealer layer perimeter were measured. Surface and microstructural characteristics of obturators and gutta-percha cones were compared by FEG-SEM and EDX analysis. No significant differences were found between groups for each examined parameter. Significant differences (P < 0.05) were reported mainly within groups. Integrity was similar among and within groups. FEG-SEM/EDX analysis of obturators revealed the presence of Ba and Zn. Carrier-based obturation technique associated with GuttaFlow Bioseal does not seem to affect sealer penetration into dentinal tubules.

Chemical-Physical Properties and Bioactivity of New Premixed Calcium Silicate-Bioceramic Root Canal Sealers

The aim of the study was to analyze the chemical−physical properties and bioactivity (apatite-forming ability) of three recently introduced premixed bioceramic root canal sealers containing varied amounts of different calcium silicates (CaSi): a dicalcium and tricalcium silicate (1−10% and 20−30%)-containing sealer with zirconium dioxide and tricalcium aluminate (CERASEAL); a tricalcium silicate (5−15%)-containing sealer with zirconium dioxide, dimethyl sulfoxide and lithium carbonate (AH PLUS BIOCERAMIC) and a dicalcium and tricalcium silicate (10% and 25%)-containing sealer with calcium aluminate, tricalcium aluminate and tantalite (NEOSEALER FLO). An epoxy resin-based sealer (AH PLUS) was used as control. The initial and final setting times, radiopacity, flowability, film thickness, open pore volume, water absorption, solubility, calcium release and alkalizing activity were tested. The nucleation of calcium phosphates and/or apatite after 28 days aging in Hanks balanced salt solution (HBSS) was evaluated by ESEM-EDX, vibrational IR and micro-Raman spectroscopy. The analyses showed for NeoSealer Flo and AH Plus the longest final setting times (1344 ± 60 and 1300 ± 60 min, respectively), while shorter times for AH Plus Bioceramic and Ceraseal (660 ± 60 and 720 ± 60 min, respectively). Radiopacity, flowability and film thickness complied with ISO 6876/12 for all tested materials. A significantly higher open pore volume was observed for NeoSealer Flo, AH Plus Bioceramic and Ceraseal when compared to AH Plus (p < 0.05), significantly higher values were observed for NeoSealer Flo and AH Plus Bioceramic (p < 0.05). Ceraseal and AH Plus revealed the lowest solubility. All CaSi-containing sealers released calcium and alkalized the soaking water. After 28 days immersion in HBSS, ESEM-EDX analyses revealed the formation of a mineral layer that covered the surface of all bioceramic sealers, with a lower detection of radiopacifiers (Zirconium for Ceraseal and AH Plus Bioceramic, Tantalum for NeoSealer Flo) and an increase in calcium, phosphorous and carbon. The calcium phosphate (CaP) layer was more evident on NeoSealer Flo and AH Plus Bioceramic. IR and micro-Raman revealed the formation of calcium carbonate on the surface of all set materials. A thin layer of a CaP phase was detected only on AH Plus Bioceramic and NeoSealer Flo. Ceraseal did not show CaP deposit despite its highest calcium release among all the tested CaSi-containing sealers. In conclusion, CaSi-containing sealers met the required chemical and physical standards and released biologically relevant ions. Slight/limited apatite nucleation was observed in relation to the high carbonation processes.

Evaluation of the Sealing Ability and Bond Strength of Two Endodontic Root Canal Sealers: An In Vitro Study

BACKGROUND

Obturation represents a critical step in endodontic treatment, which relies on a core material and a sealer. This study aims to evaluate the sealing ability and bond strength to the root canal walls of an epoxy resin-based sealer (AH-Plus®, Dentsply Sirona, Johnson City, TN, USA) and a bioceramic sealer (GuttaFlow Bioseal®, Coltène/Whaledent, GmbH + Co. KG, Langenau, Germany).

METHODS

Thirty-eight maxillary anterior teeth with single roots and identical round sections were separated into two experimental groups according to the root canal sealers used, namely, G1 = AH-Plus® and G2 = GuttaFlow Bioseal®, and two control groups, specifically, G3 = the negative control and G4 = the positive control. The sealing capacity was measured by the penetration of the radioactive isotope 99mTc. For the push-out test, the compressive force test was performed in a universal machine and the force was applied by exerting pressure on the surface of the material to be tested in the apical to the coronal direction and using three test points with different diameters.

RESULTS

GuttaFlow Bioseal® exhibited superior sealing ability compared to AH-Plus® (p = 0.003). Regarding the bond strength, AH-Plus® provided higher adhesion values than GuttaFlow Bioseal® in the three sections of the tooth root (p = 0.001).

CONCLUSIONS

GuttaFlow Bioseal® had significantly better sealing ability than AH-Plus® but lower adhesion values in the three zones of the root canal, with statistically significant differences between the groups. However, it is important to note that for the action of endodontic sealers to be maximized, the root-filling technique must be most appropriate.

The Influence of the Matrix on the Apatite-Forming Ability of Calcium Containing Polydimethylsiloxane-Based Cements for Endodontics

This study aimed to characterize the chemical properties and bioactivity of an endodontic sealer (GuttaFlow Bioseal) based on polydimethylsiloxane (PDMS) and containing a calcium bioglass as a doping agent. Commercial PDMS-based cement free from calcium bioglass (GuttaFlow 2 and RoekoSeal) were characterized for comparison as well as GuttaFlow 2 doped with dicalcium phosphate dihydrate, hydroxyapatite, or a tricalcium silicate-based cement. IR and Raman analyses were performed on fresh materials as well as after aging tests in Hank’s Balanced Salt Solution (28 d, 37 °C). Under these conditions, the strengthening of the 970 cm−1 Raman band and the appearance of the IR components at 1455−1414, 1015, 868, and 600−559 cm−1 revealed the deposition of B-type carbonated apatite. The Raman I970/I638 and IR A1010/A1258 ratios (markers of apatite-forming ability) showed that bioactivity decreased along with the series: GuttaFlow Bioseal > GuttaFlow 2 > RoekoSeal. The PDMS matrix played a relevant role in bioactivity; in GuttaFlow 2, the crosslinking degree was favorable for Ca2+ adsorption/complexation and the formation of a thin calcium phosphate layer. In the less crosslinked RoekoSeal, such processes did not occur. The doped cements showed bioactivity higher than GuttaFlow 2, suggesting that the particles of the mineralizing agents are spontaneously exposed on the cement surface, although the hydrophobicity of the PDMS matrix slowed down apatite deposition. Relevant properties in the endodontic practice (i.e., setting time, radiopacity, apatite-forming ability) were related to material composition and the crosslinking degree.

Surface characteristics and bacterial adhesion of endodontic cements

OBJECTIVES

To investigate the effect of inclusion of silver nano-particles (SNP) or bioactive glass (BG) on the surface characteristics and bacterial adhesion of prototype tricalcium silicate (TCS)-based cements alongside two commercial cements, under different aging periods and exposure conditions.

MATERIALS AND METHODS

A basic formulation of radio-opacified TCS without (TZ-base) and with additions of SNP (0.5, 1, or 2 mg/ml) or BG (10 or 20%) was used. Biodentine and intermediate restorative material (IRM) served as reference materials. Material disks were immersed in ultrapure water or fetal bovine serum (FBS) for 1, 7, or 28 days. Surface roughness (n = 3), microhardness (n = 9), and wettability (n = 6) were analyzed by standard procedures. Adhesion of Enterococcus faecalis was assessed by fluorescence microscopy (n = 5). Data from these assays were evaluated for normality and comparisons among groups were conducted with statistical procedures (p < 0.05 for significance).

RESULTS

The surface morphology of SNP- and BG-containing cements had higher roughness values than TZ-base after 28 days (p < 0.05). No differences in microhardness were observed among prototype cements (p > 0.05). Biodentine presented smooth surface characteristics and the highest hardness values (p < 0.05). The FBS-immersion resulted in surface reactions in prototype materials and Biodentine, depicted with scanning electron microscopy. All 1- and 7-day prototype cements showed negligible bacterial adhesion, while in Biodentine and IRM, noticeable E. faecalis adherence was observed from day 1 (p < 0.05).

CONCLUSIONS

Incorporation of SNP or BG did not improve the antibacterial effect of the experimental cement; all 28-day aged materials failed to inhibit bacterial adherence. The measured physical parameters did not appear to be related to the degree of bacterial adhesion. Exposure of TCS-based cements in FBS resulted in surface reactions, which did not affect bacterial adhesion.

CLINICAL RELEVANCE

Changes in the surface characteristics of prototype TCS-based cements by inclusion of SNP and BG or exposure to different environments did not affect bacterial adhesion. All experimental materials showed inferior physical properties and higher antibacterial effect than Biodentine.

Physicochemical properties of a novel bioceramic silicone-based root canal sealer

Background/purpose

With introduction into endodontics, bioceramic-based sealers have gained considerable popularity for excellent properties. The aim of this study was to investigate the physicochemical properties of a novel bioceramic silicone-based sealer, GuttaFlow Bioseal, and measure heat flow of setting reactions.

Materials and methods

Film thickness, flow, working and setting time of Bioseal were compared with other 4 kinds of sealers: iRoot SP, AH Plus, RoekoSeal and GuttaFlow2. Differential scanning calorimetry test was performed to measure heat flow.

Results

Bioseal demonstrated the highest film thickness of 44 μm, double to triple that of the other 4 sealers (P < 0.05). The highest flow was detected in iRoot SP and RoekoSeal, with values of 27.35 and 27.20 mm, while GuttaFlow2 and Bioseal had the lowest of 22.31 and 21.43 mm (P < 0.05). For each sealer, working time at 37 °C was shorter than that at 23 °C (P < 0.05). At 37 °C, Bioseal had the shortest working and setting time of 4.5 and 16.3 min, while iRoot SP showed the longest of 105.0 and 571.7 min (P < 0.05). Differential scanning calorimetry test revealed that setting process of all the tested sealers was exothermic. Bioseal reached an exothermic peak at 14 min, with almost 1.5 times peak intensity of GuttaFlow2 and RoekoSeal. Whereas iRoot SP and AH Plus reached an exothermic peak 5 h after mixing, with intensity 1/2 to 2/3 that of Bioseal.

Conclusion

The novel bioceramic silicone-based sealer Bioseal showed intense and fast exothermic reactions with characteristic physicochemical properties.

The Effect of Sealer Application Methods on Voids Volume after Aging of Three Calcium Silicate-Based Sealers: A Micro-Computed Tomography Study

During obturation, air voids are undesirable as they may provide shelter for microorganisms or passage for fluids. This study aimed to compare the occurrence of voids between three calcium silicate-based sealers (CSBSs) (MTA-Fillapex, BioRoot-RCS, Bio-C) and the change in their volume after aging. In addition, we aimed to compare voids when using two sealer application methods: lentulo-spiral (LS) and gutta-percha (GP) cone. Thirty extracted mandibular premolars (n = 30) were endodontically prepared and obturated using single GP cone (SGPC) technique. Each sealer was applied to 10 teeth (n = 10) using LS or GP. Micro-computed tomography (micro-CT) was used to quantify the volume of root filling and voids before and after 8-week storage in a phosphate-rich medium. The percentage of root filling and voids were compared between the groups using a Mann–Whitney U test and Kruskal–Wallis test with a Bonferroni correction. Before aging, the percentages of root filling volume after obturation were comparable with no significant differences between sealers (p = 0.325) or application methods (p = 0.950). After aging, the voids’ volume increased significantly in all sealers (p ≤ 0.05). However, no significant differences were found between sealers (p = 0.302). In conclusion, voids in CSBSs may not reduce in size with aging; hence, SGPC should be carefully selected for suitable cases.

A critical analysis of research methods and experimental models to study root canal fillings

Canal filling materials and techniques have been one of the most studied topics in Endodontics. A simple search using the mesh term "root canal filling" in PubMed revealed more than 11,000 articles, an impressive number that is much higher than "root canal disinfection" (5,544 articles) or even the popular "root canal preparation" (8,527 articles). The overriding importance attributed to root filling procedures is not merely intuitive. It derived from the appealing relevance given by the appearance of the white lines in common radiographs grounded on retrospective clinical data that had identified the quality of a root filling as one of the major causes of treatment failure (lack of healing). Since the publication of the Washington study, impressive efforts have been made for the release of new materials and techniques, as well as, for the development of a plethora of laboratory methods to assess the quality of root filling procedures. This narrative review aims to address and discuss the most relevant laboratory methods to assess the root canal filling. Since filling quality improvements have not translated into higher success rates, as reported in longitudinal clinical studies, more than to deliver a simple methodology-based review, this paper aims to present an in-depth critical view on the assessment of laboratory methods used to study the filling materials and techniques. Recent data indicate that the long-term dimensional stability/degradation over time of endodontic sealers plays a central role in the treatment outcome. In this context, laboratory methods should be developed focusing on predicting, at least to some degree, the long-term clinical behaviour of root canal fillings, rather than simply ranking different materials or techniques.

[Application of cold flowable gutta-percha in root canal obturation after apexification]

OBJECTIVE

To evaluate the clinical effect of root canal obturation therapy using cold flowable gutta-percha on young permanent teeth after apexification.

METHODS

Ninety cases of young permanent teeth with pulp necrosis or periapical periodontitis treated by apexification were randomly divided into two groups. The cases in each group were divided into single root canal and multiple root canal according to the number of the root canal, and divided into classifications Ⅰ, and Ⅱ/Ⅲ/Ⅳ according to Frank's classification of root development after apexification. Cold flowable gutta-percha and warm gutta-percha obturation techniques were used for root canal obturation of the two groups. The operation time was recorded, and the patients' therapy pain degree was evaluated by visual analog scale (VAS) immediately after operation. Periapical X-ray was performed after operation to evaluate the effect of the root canal filling. The total length of the root was divided into equal three parts on the X-ray film, and three-dimensional tightness of the apical, middle, and coronal region of the root canals were statistically analyzed respectively. Clinical examinations and X-ray examination were performed 6 and 12 months after the operation to evaluate the treatment success rate.

RESULTS

The operation time of cold flowable gutta-percha group was significantly lower than that of the control group, which were 51 s and 74 s (P < 0.05); The percentages of pain and discomfort in the two groups were 26.67% and 40.00%, respectively. There were two cases of underfilling and no overfilling in both groups. The percentages of proper filling and tight three-dimensional obturation in the experimental and control groups were 71.11% and 60.00% respectively; and the percentages of tight three-dimensional obturation in the apical third areas were 86.67% and 66.67%, the difference was significant (P < 0.05). There was no significant difference in the three-dimensional tightness between the two groups in the middle and coronal third areas. The percentages of tight three-dimensional obturation in classification Ⅰ groups were 86.67%, 83.33%, 93.33% and 76.67%, 90.00%, 96.67% in experimental and control group, respectively; The percentages of classification Ⅱ/Ⅲ/Ⅳ groups were 86.67%, 86.67%, 100.00% and 46.67%, 86.67%, 100.00%, respectively, and the difference was significant (P < 0.05). There were no apical lesions that occurred in either group during the one-year review period.

CONCLUSION

The application of cold flowable gutta-percha on young permanent teeth root canal obturation after apexification can achieve good obturation effect. The root obturation effect in the apical third area is significantly better than that of warm gutta-percha obturation techniques. Cold flowable gutta-percha can shorten the clinical treatment time and ameliorate the patients' therapy comfort.

Emergence of Nano-Dentistry as a Reality of Contemporary Dentistry

(1) Background. Nanotechnology offers significant alternative ways to solve scientific, medical, and human health issues. Dental biomaterials were improved by nanotechnology. It manufactures better materials or improves the existing ones and forms the basis of novel methods for disease diagnosis and prevention. Modern nanotechnology makes oral health care services more acceptable for patients. Nanotechnology is now important area of research, covering a broad range of applications in dentistry. (2) Methods. Relevant literature from Scopus published in English was selected using the keywords “nanoparticle” and “dentistry”. To the selected articles we applied the inclusion and exclusion criteria to choose the relevant ones. (3) Results. Based on the relevant articles, a literature review was prepared. This review provides an insight into the applications of nanotechnology in various branches of dentistry. We applied several regression models to fit number of papers versus time and chose the best one. We used it to construct the forecast and its 95%-confidence interval for the number of publications in 2022–2026. (4) Conclusions. It shows that a significant rise in papers is expected. This review familiarizes dentists with properties and benefits of nanomaterials and nanotechnology. Additionally, it can help scientists to consider the direction of their research and to plan prospective research projects.

In vitro evaluation of the antibacterial effect of four root canal sealers on dental biofilms

OBJECTIVES

To dynamically evaluate the effect of four root canal sealers on the killing of biofilms within dentinal tubules.

MATERIALS AND METHODS

Dentin blocks were prepared for infection of the dentinal tubules. Enterococcus faecalis VP3-181 and multi-species bacteria from two donors were cultured. After 3 days of incubation, the infected dentin specimens were rinsed with sterile water for 1 min and subjected to treatment. Additionally, multi-species bacteria from donor 1 were incubated for 3 weeks to allow biofilm maturation and then the specimens were subjected to treatment. Gutta-percha-treated dentin specimens comprised the control group. A root canal sealer (bioceramic sealers: EndoSequence BC Sealer, ProRoot Endo Sealer, or GuttaFlow Bioseal; and a traditional silicone-based sealer: Guttaflow 2) was spread onto the canal walls of the dentin. The specimens were examined with confocal laser scanning microscopy at 7, 30, or 60 days.

RESULTS

In the 3-day-old biofilm group, the proportion of killed bacteria decreased significantly from the first 7 days of treatment to 60 days of treatment for all sealers (p < 0.05). In the 3-week-old biofilm group, 60 days of exposure to bioceramic sealers resulted in more significant dead bacteria than 7-day exposures of the biofilms (p < 0.05). Bioceramic sealers were more effective in killing bacteria than the GuttaFlow 2 sealer (p < 0.05).

CONCLUSIONS

Calcium silicate-based sealers showed good antimicrobial effects against biofilms within dentinal tubules, especially in the first week in young biofilms. There is no substantive antibacterial activity observed for the examined root canal sealers against young dentinal tubule biofilms.

CLINICAL RELEVANCE

The bioceramic root canal sealers examined demonstrate minimal additional antibacterial effects after long-term exposure to young biofilms.

A comprehensive in vitro comparison of the biological and physicochemical properties of bioactive root canal sealers

OBJECTIVES

To evaluate the biological and physicochemical features of bioactive root canal sealers.

MATERIALS AND METHODS

Human periodontal ligament fibroblasts (hPDLF) and human osteoblasts (hOB) were exposed to eluates of three bioactive root canal sealers, GuttaFlow® bioseal (GF), BioRoot™ RCS (BR), and TotalFill® BC Sealer (TF), and the epoxy resin-based sealer AH plus® (AH). Cytotoxicity and cellular inflammatory response were evaluated. The osteogenic potential was examined using human mesenchymal stem cells (hMSC). Film thickness, flowability, and pH were assessed. Root canal treatment was performed on human extracted teeth to evaluate the sealers' tightness towards bacterial penetration. The antibacterial activity against common pathogens in primary root canal infections was tested.

RESULTS

AH was severely cytotoxic to hPDLF and hOB (p < 0.001). The bioactive sealers were generally less cytotoxic. IL-6 levels in hPDLF were elevated in the presence of AH (p < 0.05). AH and GF suppressed IL-6 production in hOB (p < 0.05). AH and BR stimulated the PGE₂ production in hPDLF and hOB (p < 0.05). BR was the only sealer that led to calcium deposits in hMSC (p < 0.05). TF and AH showed the lowest film thickness and the highest flowability. Bacterial tightness was best in teeth filled with AH and BR. All sealers showed similar antimicrobial activity, but the overall antimicrobial efficacy was moderate as the bacteria were reduced by just one log scale (p < 0.05).

CONCLUSIONS

This study revealed favorable in vitro results regarding the biocompatibility of the bioactive root canal sealers.

CLINICAL RELEVANCE

Bioactive root canal sealers may be a useful alternative to epoxy resin-based sealers.

Energy-Dispersive X-Ray Spectrometry Analysis and Radiopacity of Five Different Root Canal Sealers

Root canal sealers should have optimum adhesion to the root dentin, low cytotoxicity, sufficient radiopacity and high dimensional stability, which depend mainly on their chemical composition. The aims of this study were to evaluate the chemical composition of Syntex (Cerkamed, Stalowa Wola, Poland), Adseal (Meta Biomed, Cheongju-si, Korea), Sealapex (SybronEndo, Scafati, Italy), MTA Fillapex (Angelus, Londrina, Brazil) and GuttaFlow Bioseal (Coltene/Whaledent, Altstätten, Switzerland) and to determine their radiopacity comparatively. Stainless steel molds with an inner diameter of 5 mm and a depth of 2 mm were constructed. Tested root-canal sealers were mixed and poured into the molds. Following setting, digital periapical radiographs of the specimens (n=12) were taken under standard exposure conditions and the mean gray-values of specimens were measured using a computer graphics program. Then the specimens were examined by scanning electron microscopy, and Energy-dispersive X-ray analysis was performed. The data were analyzed using One-way ANOVA followed by Holm-Sidak multi-comparison test (p = 0.05). Sealapex showed higher calcium peak than MTA Fillapex, GuttaFlow Bioseal, Adseal and Syntex sealers. MTA Fillapex contained a highest amount of tungstate. Sealapex presented the highest radiopacity value among the tested materials (p < 0.05), whereas MTA Fillapex was the least radiopaque material (p < 0.05). Each root canal sealer contains different compositions of radiopacifiers including bismuth oxide, calcium tungstate and zirconium oxide. The tested root canal sealers had radiopacity values above the ISO-specified limit. Sealapex was the most radiopaque root canal sealer followed by GuttaFlow Bioseal, Syntex, Adseal and MTA Fillapex.

Effects of heat on seven endodontic sealers

PURPOSE

To examine the microscopic surface features, chemical composition, and thermodynamic profile of seven endodontic sealers (AH Plus, Adseal, MTA-Fillapex, RoekoSeal, GuttaFlow 2, GuttaFlow BioSeal, and EndoRez) exposed to high-temperature changes using an endodontic obturation device.

METHODS

The thermal properties were examined using scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Then, six disc-shaped specimens of each sealer were prepared and divided into two groups - a room temperature group and a heat exposure group - for analysis of surface and chemical changes using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS).

RESULTS

DSC analysis showed that AH Plus had the highest exothermal signal (122.9°C), while TGA analysis showed that MTA-Fillapex was most affected by increased temperature (32.4% mass loss at 230ºC). SEM analysis showed that while AH Plus and GuttaFlow BioSeal maintained their surface integrity after heat exposure, the EDS profiles demonstrated changes in the chemical composition of the sealers after heat exposure for 5 s. High-temperature exposure had a negative impact on the properties of five of the sealers (Adseal, MTA-Fillapex, RoekoSeal, GuttaFlow 2, and EndoRez).

CONCLUSION

AH Plus and GuttaFlow BioSeal showed minimal changes upon high-temperature exposure, suggesting their suitability for thermal endodontic obturation techniques.

Retreatment of Experimental Carrier-Based Obturators with the Remover NiTi Instrument: Evaluation of Apical Extrusion and Effects of New Kinematics

The objective of this study is to evaluate the retreatment time and weight of apically extruded debris yielded by two different kinematics during the removal of different root canal filling materials. Forty straight single-rooted extracted teeth were instrumented with HyFlex CM files and obturated with two different techniques: 25.04 HyFlex experimental carrier-based obturators (Coltène/Whaledent, Altstätten, Switzerland) (group 1) or 25.04 single gutta-percha cones (Roeko Coltène/Whaledent, Altstätten, Switzerland) (group 2) and Guttaflow Bioseal as the sealer. Samples were divided into four subgroups (n = 10) according to the used kinematics for the removal of root canal filling materials: continuous rotation (A) or retreatment motion (B) with a Remover and HyFlex EDM Nickel-Titanium instruments activated with a CanalPro Jeni micromotor (Coltène/Whaledent, Altstätten, Switzerland). Time for retreatment was digitally recorded, and debris extruded from the apex was collected in Eppendorf tubes and weighted with an analytical balance. Data on retreatment time and apical extrusion were statistically analyzed with the Kruskal–Wallis test (p < 0.05). Working length was achieved in all the retreated samples. The removal of root filling material resulted significantly faster with the Jeni mode (p < 0.001), and the difference was significant for the removal of both filling materials (p < 0.05). No significant differences on debris extrusion between single cone and experimental obturators groups were noted (p > 0.05), and no significant differences between kinematics (continuous rotation vs. Jeni motion) were observed (p > 0.05). All the tested retreatment strategies lead to an extrusion of material from the apex, and the weight of apically extruded debris was similar. The use of the innovative CanalPro Jeni kinematics accelerates the time for the removal of root filling materials.

What Are the Chances of Resilon to Dominate the Market Filling Materials for Endodontics?

This paper is a literature review with additional virtual analyses of the authors’ own experimental research results. Knowledge from various areas was synergistically combined, appropriately for concurrent engineering, presenting several possible methodological approaches used in research, optimizing the selection of engineering materials and the conditions of their application with particular application in endodontics. Particular attention was paid to the theoretical aspects of filling material strengths, weaknesses, opportunities, and threats SWOT analysis. Attention was paid to the original concepts of Sustainable Dentistry Development in conjunction with Dentistry 4.0, which includes endodontics as an important element. The dentists’ actions, among others, in conservative dentistry, along with endodontics, requires close cooperation with engineers and the enginering sciences. Methods of root canal preparation were described, together with selected tools, including those made of nitinol. Principles concerning the process of cleaning and shaping the pulp complex are presented. The importance of obturation methods, including the Thermo-Hydraulic-Condensation THC technique, and the selection of filling materials with the necessary sealants for the success of endodontic treatment are discussed. The experimental studies were carried out in vitro on human teeth removed for medical reasons, except for caries, for which two groups of 16 teeth were separated. After the root canal was prepared, it was filled with studs and pellets of a filling material based on polyester materials, which has gained the common trade name of resilon or, less frequently, RealSeal (SybronEndo) with an epiphany sealant. The teeth for the first group were obturated by cold lateral condensation. In the second case the obturation was performed using the Thermo-Hydraulic-Condensation technique using System B and Obtura III. The experimental leakage testing was done using a scanning electron microscope SEM and a light stereoscopic microscope LSM, as typical research tools used in materialography. The research results, in a confrontation with the data taken from the literature studies, do not indicate the domination of resilon in endodontics.

Physicochemical Properties of Two Generations of MTA-Based Root Canal Sealers

This study evaluated the physicochemical properties and the effect of solubility on the surface morphology and composition of the root canal sealers MTA-Bioseal, MTA-Fillapex, and Adseal. Discs (n = 10) of freshly mixed sealer were prepared and then analyzed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX). The discs were immersed for 1, 7, 14, and 28 days in deionized water. The solubility %; pH change of the solution; and released calcium, phosphate, and silicon were measured for each period. The flowability and film thickness were also evaluated. Changes in the surface morphology and composition after 28 days of immersion were evaluated by SEM/EDX. The data were statistically analyzed by one-way ANOVA at p < 0.05. The FTIR and EDX results revealed similar compositions of MTA-Bioseal and MTA-Fillapex, but with different concentrations. The two MTA-based sealers had higher solution alkalinity (pH > 10) than Adseal (pH ≈ 8.5). MTA-Fillapex exhibited the highest solubility % and the largest calcium and silicon ion release. MTA-Bioseal had the highest phosphate ion release. After 28 days, the sealer surfaces showed large micropores, with larger pores in MTA-Fillapex. Adseal had an intermediate flowability but exhibited the greatest film thickness. Finally, the highest solubility and largest amount of silicon release was exhibited by MTA-Fillapex, which might predispose it to the development of large micropores, compromising the apical seal of obturation.

Is Gutta-Percha Still the “Gold Standard” among Filling Materials in Endodontic Treatment?

The paper is an extensive monographic review of the literature, and also uses the results of the authors’ own experimental research illustrating the noticed developmental tendencies of the filling material based on gutta-percha. The whole body of literature proves the correctness of the research thesis that this material is the best currently that can be used in endodontics. Caries is one of the most common global infectious diseases. Since the dawn of humankind, the consequence of the disease has been the loss of dentition over time through dental extractions. Both tooth caries and tooth loss cause numerous complications and systemic diseases, which have a serious impact on insurance systems and on the well-being, quality, and length of human life. Endodontic treatment, which has been developing since 1836, is an alternative to tooth extraction. Based on an extensive literature review, the methodology of qualifying patients for endodontic treatment was analyzed. The importance of selecting filling material and techniques for the development and obturation of the root canal during endodontic treatment was described. Particular attention was paid to the materials science aspects and the sequence of phase transformations and precipitation processes, as well as the need to ensure the stoichiometric chemical composition of Ni–Ti alloys, and the vacuum metallurgical processes and material processing technologies for the effects of shape memory and superelasticity, which determine the suitability of tools made of this alloy for endodontic purposes. The phenomena accompanying the sterilization of such tools, limiting the relatively small number of times of their use, play an important role. The methods of root canal preparation and obturation methods through cold side condensation and thermoplastic methods, including the most modern of them, the thermo-hydraulic condensation (THC) technique, were analyzed. An important element of the research hypothesis was to prove the assumption that to optimize the technology of development and obturation of root canals, tests of filling effectiveness are identified by the density and size of the gaps between the root canal wall, and the filling methods used and devices appropriate for material research, using mainly microscopy such as light stereoscopic (LSM) and scanning electron (SEM). The most beneficial preparations were obtained by making a longitudinal breakthrough of 48 natural human teeth, extracted for medical reasons, different from caries, with compliance with all ethical principles in this field. The teeth were prepared using various methods and filled with multiple obturation techniques, using a virtual selection of experimental variants. The breakthroughs were made in liquid nitrogen after a one-sided incision with a narrow gap created by a diamond disc using a materialographic cutter. The best effectiveness of the root canal filling was ensured by the technology of preparing the root canals with K3 rotary nitinol tools and filling the teeth with the THC thermoplastic method using the System B and Obtura III devices with studs and pellets of filling material based on gutta-percha after covering the root canal walls with a thin layer of AH Plus sealant. In this way, the research thesis was confirmed.

Biological interactions between calcium silicate-based endodontic biomaterials and periodontal ligament stem cells: A systematic review of in vitro studies

BACKGROUND

Most recently, the biological interactions, that is cytocompatibility, cell differentiation and mineralization potential, between calcium silicate-based biomaterials and periodontal ligament stem cells (PDLSCs) have been studied at an in vitro level, in order to predict their clinical behaviour during endodontic procedures involving direct contact with periodontal tissues, namely root canal treatment, endodontic surgery and regenerative endodontic treatment.

OBJECTIVE

The aim of the present systematic review was to present a qualitative synthesis of available in vitro studies assessing the biological interaction of PDLSCs and calcium silicate-based biomaterials.

METHODOLOGY

The present review followed PRISMA 2020 guidelines. An advanced database search was performed in Medline, Scopus, Embase, Web of Science and SciELO on 1 July 2020 and last updated on 22 April 2021. Studies assessing the biological interactions of PDLSCs with calcium silicate-based sealers (CSSs) and/or cements (CSCs) at an in vitro level were considered for inclusion. The evaluation of the 'biological interaction' was defined as any assay or test on the cytotoxicity, cytocompatibility, cell plasticity or differentiation potential, and bioactive properties of PDLSCs cultured in CSC or CSS-conditioned media. Quality (risk of bias) was assessed using a modified CONSORT checklist for in vitro studies of dental materials.

RESULTS

A total of 20 studies were included for the qualitative synthesis. CSCs and CSSs, as a group of endodontic materials, exhibit adequate cytocompatibility and favour the osteo/cementogenic differentiation and mineralization potential of PDLSCs, as evidenced from the in vitro studies included in the present systematic review.

DISCUSSION

The influence of the compositional differences, inclusion of additives, sample preparation, and varying conditions and manipulations on the biological properties of calcium silicate-based materials remain a subject for future research.

CONCLUSIONS

Within the limitations of the in vitro nature of the included studies, this work supports the potential use of calcium silicate-based endodontic materials in stem cell therapy and biologically based regenerative endodontic procedures.

REGISTRATION

OSF Registries; https://doi.org/10.17605/OSF.IO/SQ9UY.

Comparison of bacterial microleakage of three bioactive endodontic sealers in simulated underwater diving and aviation conditions

BACKGROUND

Bacterial microleakage is an important cause of apical periodontitis and endodontic treatment failure. This study aimed to assess the bacterial microleakage of nano-mineral trioxide aggregate (nano-MTA) as a sealer, Endoseal MTA, and GuttaFlow Bioseal sealers in atmospheric pressure, and simulated underwater diving and aviation conditions.

METHODS

In this in vitro, experimental study, 180 extracted single-rooted teeth were cleaned and shaped, and were then randomly divided into three groups for single-cone obturation using Endoseal MTA, GuttaFlow Bioseal, or nano-MTA as a sealer. Each group was then randomly divided into three subgroups, and subjected to ambient atmospheric pressure, 2 atm pressure (to simulate underwater diving), and 0.5 atm pressure (to simulate aviation) using a custom-made pressure chamber. The teeth then underwent microbial leakage test using Streptococcus mutans (S. mutans), and the percentage of samples showing microleakage was recorded for up to 1 month, and analyzed using the Chi-square test.

RESULTS

The three sealer groups were significantly different regarding bacterial microleakage (P < 0.05). The nano-MTA group showed significantly higher microleakage after 15 days than the other two groups (P = 0.006). The effect of pressure on bacterial microleakage was not significant in any sealer group (P > 0.05).

CONCLUSION

Within the limitations of this in vitro study, it may be concluded that single-cone obturation technique using nano-MTA as a sealer results in lower resistance to bacterial microleakage compared with the use of GuttaFlow Bioseal, and Endoseal MTA. Pressure changes in simulated underwater diving and aviation conditions had no significant effect on bacterial microleakage. Trial Registration Number This is not a human subject research.

Virtual Approach to the Comparative Analysis of Biomaterials Used in Endodontic Treatment

The importance of endodontics is presented within our own concept of Dentistry Sustainable Development (DSD) consisting of three inseparable elements; i.e., Advanced Interventionist Dentistry 4.0 (AID 4.0), Global Dental Prevention (GDP), and the Dentistry Safety System (DSS) as a polemic, with the hypothesis of the need to abandon interventionist dentistry in favour of the domination of dental prevention. In view of the numerous systemic complications of caries that affect 3−5 billion people globally, endodontic treatment effectively counteracts them. Regardless of this, the prevention of oral diseases should be developed very widely, and in many countries dental care should reach the poorest sections of society. The materials and methods of clinical management in endodontic procedures are characterized. The progress in the field of filling materials and techniques for the development and obturation of root canals is presented. The endodontics market is forecast to reach USD 2.1 billion in 2026, with a CAGR of 4.1%. The most widely used and recognized material for filling root canals is gutta-percha, recognized as the “gold standard”. An alternative is a synthetic thermoplastic filler material based on polyester materials, known mainly under the trade name Resilon. There are still sceptical opinions about the need to replace gutta-percha with this synthetic material, and many dentists still believe that this material cannot compete with gutta-percha. The results of studies carried out so far do not allow for the formulation of a substantively and ethically unambiguous view that gutta-percha should be replaced with another material. There is still insufficient clinical evidence to formulate firm opinions in this regard. In essence, materials and technologies used in endodontics do not differ from other groups of materials, which justifies using material engineering methodology for their research. Therefore, a detailed methodological approach is presented to objectify the assessment of endodontic treatment. Theoretical analysis was carried out using the methods of procedural benchmarking and comparative analysis with the use of contextual matrices to virtually optimize the selection of materials, techniques for the development and obturation of root canals, and methods for assessing the effectiveness of filling, which methods are usually used, e.g., in management science, and especially in foresight research as part of knowledge management. The results of these analyses are presented in the form of appropriate context matrices. The full usefulness of the research on the effectiveness and tightness of root canal filling using scanning electron microscopy is indicated. The analysis results are a practical application of the so-called “digital twins” approach concerning the virtual comparative analysis of biomaterials used in endodontic treatment.

Effect of sintering temperature on the physiochemical properties, microstructure, and compressive strength of a bioceramic root canal sealer reinforced with multi-walled carbon nanotubes and titanium carbide

AIM

Bioceramic root canal sealers like BioRoot RCS have received significant attention for use in endodontics. The addition of a nanophase material like multi-walled carbon nanotubes (MWCNTs) and titanium carbide (TC) to its matrix combined with pressureless sintering might have the potential for improved physiochemical, microstructure, and compressive strength properties.

METHOD

ology: MWCNTs and TC nanomaterials were added at a percentage of 1 wt% to a definite weight of pristine BioRoot RCS. Two composites were prepared by ball milling followed by pressureless sintering in static nitrogen at temperatures 600 °C and 800 °C. The setting time, solubility, pH, compressive strength, and density were determined and compared to pristine BioRoot RCS. The microstructural properties of the composites were investigated by XRD, FTIR, Raman spectroscopy, and SEM.

RESULTS

The final setting time before and after sintering at 600 °C of the composites was accelerated compared to Bioroot RCS (p = 0.016). The solubility of Bioroot/TC sintered at 600 °C was the lowest (p = 0.07) and its compressive strength was the highest among the sintered samples (p = 0.01). The incorporation of MWCNTs and TC had a significant increase in the compressive strength of Bioroot RCS (p < 0.05).

CONCLUSION

The obtained results support the addition of nanomaterials to Bioroot RCS and the use of pressureless sintering.

Natural Polymer Eucommia Ulmoides Rubber: A Novel Material

As the second natural rubber resource, Eucommia ulmoides rubber (EUR) from Eucommia ulmoides Oliver is mainly composed of trans-1,4-polyisoprene, which is the isomer of natural rubber cis-1,4-polyisoprene from Hevea brasiliensis. In the past few years, the great potential application of EUR has received increasing attention, and there is a growing awareness that the natural polymer EUR could become an emerging research topic in field of the novel materials due to its unique and excellent duality of both rubber and plastic. To gain insight into its further development, in this review, the extraction, structure, physicochemical properties, and modification of EUR are discussed in detail. More emphasis on the potential applications in the fields of the environment, agriculture, engineering, and biomedical engineering is summarized. Finally, some insights into the challenges and perspectives of EUR are also suggested.

Behaviour of different bioactive glasses incorporated in polydimethylsiloxane endodontic sealer

OBJECTIVES

The aim of this study was to analyze the behavior of different bioactive glass fillers (BAGs) embedded in a polydimethylsiloxane matrix of an endodontic sealer.

METHODS

Three different endodontic sealers were fabricated using S53P4, 45S5 and 18-06 glass fillers. Endodontic sealer Guttaflow Bioseal consisting of polydimethylsiloxane (PDMS) matrix was used as base of the experimental sealers. Behaviors of different glass fillers leaching from polymer matrix was studied in vitro for 14 days by measuring static ion dissolution profiles of Si, Na, Ca and P -ions. In addition, pH of the simulated bodyfluid (SBF) was monitored during the 14 days and all the sealer samples was examined with SEM/EDX analysis on the surface. Identical but non-glass filler containing polydimethylsiloxane-based sealer was used as a control material.

RESULTS

By the time point of 24 h sealer with 45S5 had released twice as much of Si-ions compared to sealer with S53P4. No statistical differences of Na, Ca and P -ions dissolution were observed in the first 168 h for any groups whereas concentrations of Ca and P -ions decreased with 45S5 significantly after 336 h. Highest pH was measured for sealers with glass filler 45S5 and S53P4 (7.64-7.65). Visible mineral precipitation was observed only on sealer surfaces after 336 h' time period with groups of 45S5 and S53P4. However, presence of calcium and phosphorus oxides was confirmed only with 45S5.

SIGNIFICANCE

Bioactive glass type 45S5 outperforms S53P4 and 18-06 by acting more dynamically in vitro set-up.

Effects of heating on the physical properties of premixed calcium silicate-based root canal sealers

The purpose of this study was to examine the effect of heating on the physical properties of four types of premixed calcium silicate-based root canal sealers. Endoseal MTA, Well-Root ST, EndoSequence BC Sealer, EndoSequence BC Sealer HiFlow, and AH Plus (epoxy resin root canal sealer) were heated at 100°C for 1 min, and changes in setting time, flow, and film thickness were evaluated in accordance with ISO 6876:2012 standards. In addition, pH measurement and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses of the set materials were performed. All root canal sealers heated at 100°C showed significant decreases in setting time and flow, particularly Endoseal MTA. In addition, the film thickness of Endoseal MTA increased significantly after heating at 100°C. The pH and SEM/EDS results were not affected by heating. Heating calcium silicate-based root canal sealers accelerated setting time, decreased flow, and increased film thickness. However, the degree of these changes varied among the products. The present findings indicate that heat-induced changes in the physical properties of calcium silicate-based root canal sealers could adversely affect the quality of warm vertical condensation technique.

Influence of particulate alkaline biomaterial remnants in dentin on the adhesion of two resin-based bonding systems

To study aimed to evaluate the influence of infiltrated alkaline biomaterials on the bond strength of composite obtained with etch and rinse and universal adhesive systems. Coronal dentin of extracted human molars was exposed and infiltrated with calcium hydroxide, MTA, or bioactive glass 45S5 powder. Non-infiltrated dentin specimens served as controls. Subsequently, dentin was either acid-etched or not, and remaining alkali content was measured by pH induction in water. Shear bond strength of an etch-and rinse system (Adper Single Bond 2) on etched dentin was then compared to that of a universal counterpart (Single Bond [(Scotchbond) Universal] by the same manufacturer. Data was compared between groups using one-way ANOVA and Tukey's HSD. On sound dentin, the etch-and-rinse system adhered stronger than the universal system (p < .05). All particles rendered the dentin alkaline. Acid etching reduced the alkali content in the infiltrated dentin. However, bond strength values were stronger with the universal system without etching than with the etch-and rinse counterpart, which lost more than 60% of its adhesiveness. The universal adhesive system was less susceptible to alkaline contamination of the dentin than the etch-and-rinse counterpart. Based on the similar composition of the two systems under investigation, this is likely to the due to its 10-MDP component.

Sealing Ability of AH Plus and GuttaFlow Bioseal

The objective of root canal obturation is to achieve a fluid-tight seal. Recently, GuttaFlow bioseal (GB), a root canal sealer composed of polydimethylsiloxane, gutta-percha particles, and bioactive glass ceramics, has been developed, to enhance the sealing ability of root canal filling material. The objective of this study was to assess the sealing ability of GB using a subnanoliter-scaled fluid-flow measuring device and to compare with that of AH Plus (AH). The fluid flow in root canal-filled teeth using either gutta-percha cone (GP) with AH (GAR; n = 10) or GP with GB (GBR; n = 10) and in GP inserted in AH blocks (GA; n = 10) or GP inserted in GB blocks (GB; n = 10) was measured. In addition, fluid flow in sealer blocks of AH (A; n = 10) and GB (B; n = 10), which served as negative controls, was measured. Root canal-filled teeth using GP without any sealer (GR) acted as positive controls (n = 10). The leakage was obtained by calculating the volume of moved water by time (s), after stabilization of the fluid flow was achieved. Statistical analysis was performed using the Kruskal–Wallis test and Mann–Whitney U-test with Bonferroni correction. A p value less than 0.00238 (0.05/21) was considered significantly different. The mean leakages (nL/s) in the groups are as follows: GAR, 0.0958 ± 0.0543; GBR, 0.0223 ± 0.0246; GA, 0.0644 ± 0.0803; GB, 0.0267 ± 0.0182; A, 0.0055 ± 0.0057; B, 0.0052 ± 0.005; and GR, 0.2892 ± 0.3018. The mean leakage in the GBR group was lower than that in the GAR group (p = 0.001), while the mean leakages in the GA and GB groups were not significantly different. GuttaFlow bioseal can be useful in single-cone obturation technique.

Physical Properties and Biofunctionalities of Bioactive Root Canal Sealers In Vitro

Calcium silicate-based bioactive glass has received significant attention for use in various biomedical applications due to its excellent bioactivity and biocompatibility. However, the bioactivity of calcium silicate nanoparticle-incorporated bioactive dental sealer is not much explored. Herein, three commercially available bioactive root canal sealers (Endoseal MTA (EDS), Well-Root ST (WST), and Nishika Canal Sealer BG (NBG)) were compared with a resin-based control sealer (AH Plus (AHP)) in terms of physical, chemical, and biological properties. EDS and NBG showed 200 to 400 nm and 100 to 200 nm nanoparticle incorporation in the SEM image, respectively, and WST and NBG showed mineral deposition in Hank's balanced salt solution after 28 days. The flowability and film thickness of all products met the ISO 3107 standard. Water contact angle, linear dimensional changes, and calcium and silicate ion release were significantly different among groups. All bioactive root canal sealers released calcium ions, while NBG released ~10 times more silicon ions than the other bioactive root canal sealers. Under the cytocompatible extraction range, NBG showed prominent cytocompatibility, osteogenecity, and angiogenecity compared to other sealers in vitro. These results indicate that calcium silicate nanoparticle incorporation in dental sealers could be a potential strategy for dental periapical tissue regeneration.

Temperature changes affect the rheological properties of a silicone-based and an epoxy resin-based root canal sealers

To evaluate temperature changes on the rheological properties (setting time and complex viscosity (η*)) of GuttaFlow Bioseal (GFB) and AH Plus Jet (AHPJ). Rheological measurements were performed in oscillating mode at the strain amplitude and angular frequency of 0.01% and 10 rad s^-1 , respectively. Each sealer (n = 5) was tested running a temperature ramp (rapid increase to 80°C, 1 min constantly at 80°C, and slower decrease to 37°C). Control groups (n = 5) were tested at a constant temperature of 37°C. Kolmogorov-Smirnov and one-way ANOVA (P < 0.05) statistical tests were performed. The temperature ramp reduced setting time of GFB (24.85 to 4.45 min) (P < 0.05), but did not alter that of AHPJ (P > 0.05). GFB exhibited an increased η*, whereas the AHPJ η* was decreased when heated (P < 0.05). Rheological properties of sealers were negatively affected by temperature changes.

Immunoinflammatory response and bioactive potential of GuttaFlow bioseal and MTA Fillapex in the rat subcutaneous tissue

To evaluate the effect of GuttaFlow bioseal (GFB) and MTA Fillapex (MTAF) in comparison with Endofill (EF) in the subcutaneous tissue. Polyethylene tubes with GFB, MTAF, EF or empty tubes (control group; CG) were implanted into subcutaneous of rats. After 7, 15, 30 and 60 days, the capsule thickness, inflammatory reaction, interleukin-6 (IL-6), vascular endothelial growth factor (VEGF), caspase-3, TUNEL-positive cells, von Kossa and ultrastructural features were evaluated. The data were statistically analyzed (p ≤ 0.05). At all periods, the number of IL-6- and VEGF-immunolabelled cells, and capsule thickness were lower in GFB than MTAF, which was lower than EF (p < 0.0001). At 60 days, the number of inflammatory cells was similar in GFB and MTAF (p = 0.58). Significant differences in the number of TUNEL- and caspase-3-positive cells were not observed among GFB, MTAF and CG whereas the highest values were found in EF specimens. The EF specimens exhibited several cells with condensed chromatin, typical of apoptosis. von Kossa-positive and birefringent structures were only observed in GFB and MTAF, suggesting the presence of calcite crystals. Taken together, these results show that cellular and structural damage induced by GFB and MTAF sealers were recovery over time. Moreover, these sealers express bioactive potential in subcutaneous tissue.

Do Contaminating Substances Influence the Rheological Properties of Root Canal Sealers?

INTRODUCTION

This study evaluated the effect of residual substances derived from irrigant solutions and intracanal medications on the rheological properties of a silicone, gutta-percha, and bioactive glass-based sealer in comparison with an epoxy resin-based sealer.

METHODS

Thin films of contaminants (0.5 μL) (3% sodium hypochlorite [NaOCl], chlorhexidine digluconate [CHX], 17% EDTA, calcium hydroxide, 40% citric acid, or distilled water [DW]) were applied along with freshly mixed GuttaFlow Bioseal (GFB; Coltene/Whaledent, Langenau, Germany) or AH Plus Jet (Dentsply DeTrey, Konstanz, Germany) on the lower plate of a dynamic rheometer. Rheological measurements were performed in oscillating mode at the strain amplitude, angular frequency, and constant temperature of 0.01%, 10 rad/s, and 37°C, respectively. Samples without contaminants served as controls. All measurements were performed 5 times. The Kolmogorov-Smirnov test and 1-way analysis of variance followed by the Student-Newman-Keuls test were performed to analyze the results (P < .05).

RESULTS

The contaminants did not alter the setting time of GFB compared with the controls; however, CHX and calcium hydroxide decreased its complex viscosity (ƞ*) (P < .05). The setting time of AH Plus Jet was increased by DW, CHX, citric acid, and EDTA (P < .05). All contaminants decreased its ƞ* at the setting point (P < .05). NaOCl led to the greatest alteration of its rheological parameters.

CONCLUSIONS

Irrigant solutions and intracanal medications adversely affected at least 1 of the tested rheological properties of both sealers, except for DW and 3% NaOCl, which did not alter any rheological property of GFB.

Bioactive Glass-Based Endodontic Sealer as a Promising Root Canal Filling Material without Semisolid Core Materials

Endodontic treatment for a tooth with damaged dental pulp aims to both prevent and cure apical periodontitis. If the tooth is re-infected as a result of a poorly obturated root canal, periapical periodontitis may set-in due to invading bacteria. To both avoid any re-infection and improve the success rate of endodontic retreatment, a treated root canal should be three-dimensionally obturated with a biocompatible filling material. Recently, bioactive glass, one of the bioceramics, is focused on the research area of biocompatible biomaterials for endodontics. Root canal sealers derived from bioactive glass-based have been developed and applied in clinical endodontic treatments. However, at present, there is little evidence about the patient outcomes, sealing mechanism, sealing ability, and removability of the sealers. Herein, we have developed a bioactive glass-based root canal sealer and provided evidence concerning its physicochemical properties, biocompatibility, sealing ability, and removability. We also review the classification of bioceramics and characteristics of bioactive glass. Additionally, we describe the application of bioactive glass to facilitate the development of a new root canal sealer. Furthermore, this review shows the potential application of bioactive glass-based cement as a root canal filling material in the absence of semisolid core material.