Analyzing the Bioactivity of a Novel Bone Cement: An In Vitro Study

AIM

To analyze the effect of bioactive bone cement (BBC) placed in a phosphate buffer saline solution in comparison to mineral trioxide aggregate (MTA).

METHODOLOGY

Ten samples each of BBC (group 1) and MTA (group 2) were prepared and stored in a phosphate buffer saline solution. After three days of storage, white precipitates were formed on the surface of the samples. The solution with precipitates from each sample was analyzed for the presence of calcium and phosphate ions with coupled plasma atomic spectroscopy.

RESULTS

BBC showed a significant amount of calcium and phosphate release after a seven-day storage period in phosphate buffer saline solution. Calcium release was significantly higher in group 1 (MTA) (p < 0.001) compared to that in group 2 (BBC), while group 2 (BBC) (p < 0.001) exhibited greater phosphate release compared to group 1 (MTA).

CONCLUSION

BBC (group 2) retains its bioactivity when it comes into contact with a stimulated oral environment (STF). This demonstrates that BBC is bioactive in a simulated oral environment. Moreover, it retained good handling properties and could be easily manipulated into a dough form. Clinically, in cases of apical surgery, internal resorption or perforation repair where material placement poses difficulty, BBC will prove to be beneficial.

Fracture Resistance of Simulated Immature Teeth Filled with Three Types of Calcium Silicate Cement after Intracanal Medication with Ca(OH)2: An Ex Vivo Study

Objectives

The aim of this study was to evaluate the 1-day fracture resistance of simulated immature teeth with an apical plug with ProRoot MTA, MTA Angelus, and RetroMTA after calcium hydroxide intracanal medication.

Materials and Methods

Sixty extracted, single-rooted human mandibular premolars were randomly divided into six groups of 10 teeth each. Firstly, to standardize the 9 mm root length, the crowns were cut off at and 9 mm below the cementoenamel junction transversely. Simulations for immature apices were carried out by using No. 1-6 Peeso reamers to pass through the apex to obtain a diameter of 1.7 mm at the apical opening. One group served as a negative control without any treatment, while the other groups received 30 days of calcium hydroxide intracanal medication. Four groups were plugs with 4 mm of ProRoot MTA, MTA Angelus, RetroMTA, and gutta-percha, respectively. The last one was served as a positive control group without filling inside. After 1 day of incubation, specimens were vertically loaded in a universal testing machine at a crosshead speed of 1 mm/min until fracture occurred. The peak load to fracture (Newton) and fracture pattern were recorded. A one-way analysis of variance (ANOVA) followed by Tukey's HSD test was used for data analysis.

Results

The highest mean load to fracture was shown in the negative control group (543.33 ± 37.17 N), followed by ProRoot MTA (432.82 ± 68.06 N), MTA Angelus (396.92 ± 59.93 N), RetroMTA (389.08 ± 56.25 N), and gutta-percha (283.28 ± 43.40 N), and the lowest belonged to the positive control group (239.98 ± 27.19 N). The significant differences were found between both the control and experimental groups with an apical plug with calcium silicate cement (p  < 0.05). There were no significant differences among those three apical plugs (p  > 0.05).

Conclusion

Apical plugs with ProRoot MTA, MTA Angelus, and RetroMTA had an immediate strengthening effect on simulated immature teeth after calcium hydroxide intracanal medication had been used.

Assessment of the biointeractivity of a novel vital pulp therapy agent derived from eggshell biowaste: An in vitro study

This study aimed to assess the calcium (Ca2+) and hydroxyl (OH-) ion-releasing ability, namely the biointeractivity of eggshell-derived hydroxyapatite (ESDHA) in comparison with mineral trioxide aggregate (MTA) and calcium hydroxide (CH). ESDHA, MTA and CH samples (n = 10; 8 × 1.6 mm) were immersed in 10 mL of deionised water (37°C, pH 6.8). Ca2+ and OH- ion releases were detected in 1, 7 and 21 days. Scanning electron microscopy and Fourier transform infrared spectroscopy analyses were also conducted. IBM SPSS 20.0 was used for statistical analyses. The cumulative Ca2+ ions (56.22 ± 11.28 ppm) were detected as most significant in ESDHA (day 21; p < 0.05). The OH- ion values of the ESDHA group were statistically higher than MTA and CH (days 1 and 7; p < 0.05). ESDHA and CH showed a similar pattern with sharp peaks in Ca2+, oxygen and carbon elements. ESDHA being a sustainable material with a high ion-releasing ability may be a preferable alternative to the commercial vital pulp therapy agents.

Interfacial adaptation of NeoMTA Plus, BioRoot RCS and MTA in root-end cavities: A micro-CT study

AIM

This study aimed to use the micro-computed tomography to evaluate the interfacial adaptation and the presence of gaps of NeoMTA Plus, BioRoot RCS, and MTA in the root-end cavities.

METHODOLOGY

Thirty standardized bovine roots measuring 15 mm in length were selected. Chemical-mechanical preparation was performed up to instrument #80 and obturation with the cold lateral compaction technique with cement based on zinc oxide and eugenol. The roots were kept at 37°C for 7 days. Afterward, apicectomy of the apical 3 mm and a root-end filling cavity was performed at 3 mm depth. Micro-computed tomography (micro-CT) was performed to measure the volume of the retroactivity. The roots were divided by stratified randomization into three groups according to the retro-end filling material: NeoMTA Plus, BioRoot RCS, and MTA. A new micro-CT was performed to assess the presence of voids in the root-end filling material and between it and the canal wall. One-way ANOVA and Tukey tests were performed using the BioEstat 4.0 program.

RESULTS

There was no difference in the initial volume values of the root-end cavities (p > .05). After the insertion of root-end filling materials, the most significant volumes of voids were observed in the NeoMTA Plus group (p < .05), with no difference for the BioRoot RCS and MTA Angelus groups (p > .05).

CONCLUSION

Micro-computed tomography showed that MTA and BioRoot RCS have better interfacial adaptation and presented fewer number of gaps than NeoMTA Plus when used as root-end filling materials.

RESEARCH HIGHLIGHTS

Micro-computed tomography evaluation of different root-end fillings materials.

A paradigm shift from calcium hydroxide to bioceramics in direct pulp capping: A narrative review

For many years, calcium hydroxide (CH) was the preferred material for direct pulp capping (DPC), occupying an elevated position. The collapse of this paradigm is due to the emergence of bioceramics with less pulpal inflammation and superior mineralization abilities than CH. The goal of the current article was directed to: (1) review the history of DPC "the idea of an exposed pulp as a hopeless organ has given way to one of healing and optimism," (2) classify the bioceramics in dentistry, and (3) explain and compare the mechanism by which dentin barriers for CH and bioceramics are formed. A comprehensive literature search of the database was conducted using PubMed, Google Scholar, and Scopus utilizing the following terms: Biodentine, calcium hydroxide, calcium aluminate, calcium phosphate, calcium silicate, direct pulp capping, NeoMTA Plus, Quick-Set2, and TotalFill. Reference mining of the selected publications was utilized to discover other studies and strengthen the results. Only works written in English were taken into consideration, and there were no restrictions on the year of publication. Bioceramic materials might be used as an intriguing substitute for CH. Compared to CH, they induced more positive pulpal reactions.

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.

Intracoronal tooth bleaching - A review and treatment guidelines

Intracoronal bleaching is a minimally invasive procedure that was introduced into dentistry in the 19th century. The role of that procedure in enhancing the colour of teeth subjected to internal discolouration while being conservative made it extremely popular amongst dental professionals. Different materials and techniques have been utilized over the years attempting to obtain predictable long-term results while minimizing any associated risks. Contemporarily, bleaching agents are mainly based on peroxide-releasing compounds in different formulations and delivery systems. Different theories have been formulated on the bleaching mechanism of such agents, but the exact mechanism is yet to be proven. The effect of hydrogen peroxide-based bleaching agents on the organic structure of enamel and dentine has been extensively investigated to address the effects of bonding of resin-based restorative materials to hard tooth structure. Multiple case reports raised a concern about the contribution of intracoronal bleaching in developing invasive root resorption. Modification of intracoronal bleaching techniques was thus necessary to address such concerns. This review will provide a summary of the important aspects of intracoronal bleaching, focusing on how it applies to the contemporary clinical setting. © 2023 Australian Dental Association.

Rheological Properties and Setting Kinetics of Bioceramic Hydraulic Cements: ProRoot MTA versus RS

Hydraulic calcium silicate-based cements (HCSCs) have become a superior bioceramic alternative to epoxy-based root canal sealers in endodontics. A new generation of purified HCSCs formulations has emerged to address the several drawbacks of original Portland-based mineral trioxide aggregate (MTA). This study was designed to assess the physio-chemical properties of a ProRoot MTA and compare it with newly formulated RS+, a synthetic HCSC, by advanced characterisation techniques that allow for in situ analyses. Visco-elastic behaviour was monitored with rheometry, while phase transformation kinetics were followed by X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and Raman spectroscopies. Scanning electron microscopy with energy-dispersive spectroscopy, SEM-EDS, and laser-diffraction analyses was performed to evaluate the compositional and morphological characteristics of both cements. While the kinetics of surface hydration of both powders, when mixed with water, were comparable, an order of magnitude finer particle size distribution of RS+ coupled with the modified biocompatible formulation proved pivotal in its ability to exert predictable viscous flow during working time, and it was more than two times faster in viscoelastic-to-elastic transition, reflecting improved handling and setting behaviour. Finally, RS+ could be completely transformed into hydration products, i.e., calcium silicate hydrate and calcium hydroxide, within 48 h, while hydration products were not yet detected by XRD in ProRoot MTA and were obviously bound to particulate surface in a thin film. Because of the favourable rheological and faster setting kinetics, synthetic, finer-grained HCSCs, such as RS+, represent a viable option as an alternative to conventional MTA-based HCSCs for endodontic treatments.

Fast-Setting Calcium Silicate-Based Pulp Capping Cements-Integrated Antibacterial, Irritation and Cytocompatibility Assessment

Calcium silicate-based cements (CSCs) are endodontic materials widely used in vital pulp-capping approaches. Concerning the clinical application, the reduced set time and pre-mixed formulations are relevant characteristics during the operative management of pulpal exposure, aiming to optimise the work time and improve cross-infection/asepsis control. Additionally, clinical success seems to be greatly dependent on the biological performance of the materials that directly contact the living pulp. As such, this work approaches an integrative biological characterisation (i.e., antibacterial, irritation, and cytocompatibility assays) of three fast-setting CSCs-Biodentine^TM, TotalFill^® BC RRM™ Fast Putty, and Theracal LC^®. These cements, after setting for 24 h, presented the expected topography and elemental composition (assessed by scanning electron microscopy, coupled with EDS analysis), in accordance with the information of the manufacturer. The set cements displayed a significant and similar antibiofilm activity against S. mutans, in a direct contact assay. Twenty-four-hour eluates were not irritant in the standardised CAM assay, but elicited distinct dose- and time-dependent cytotoxicity profiles on fibroblastic cells-i.e., Biodentine was devoid of toxicity, TotalFill presented a slight dose-dependent initial toxicity that was easily overcome, and Theracal LC was deleterious at high concentrations. When compared to long-setting ProRoot MTA cement, which highlighted the pursued integrative approach, Biodentine presented a similar profile, but TotalFill and Theracal LC displayed a poorer performance regarding antibiofilm activity/cytocompatibility features, and Theracal LC suggested eventual safety concerns.

Penetration of Three Endodontic Sealers in Simulated Lateral Canals during the Lateral Condensation Technique: An In Vitro Study

Objective

This study aimed to compare the penetration depths of AH Plus, BioRoot RCS, and GuttaFlow 2 into simulated lateral canals when used with the cold gutta-percha lateral compaction technique.

Materials and Methods

Twelve resin training blocks (4 canals perch each resin block) were used. Each primary artificial canal had two lateral canals (apical and coronal). The main canals were instrumented with WaveOne Gold and irrigated with distilled water. The resin blocks were divided into three groups (N = 4 each/16 artificial canals), according to the type of root canal sealer; Group I: AH Plus, Group II: BioRoot RCS, and Group III: GuttaFlow 2. All canals were obturated with the cold lateral condensation technique. The linear extension of each endodontic sealer into the apical and coronal lateral canals was measured using a digital stereomicroscope and measuring software. Data were statistically analyzed using a one-way analysis of variance. The percentages of filling of the lateral canals were calculated and statistically compared using the Mann–Whitney test.

Results

The experimental sealers exhibited variable penetration depths into the lateral canals. All sealers showed significantly better penetration ability into the apical lateral canals than the coronal lateral canals (P < 0.05). AH Plus (3.184 ± 0.012 mm/99.5%) and GuttaFlow 2 (3.176 ± 0.017 mm/99.25%) were significantly better than BioRoot RCS (3.096 ± 0.026 mm/96.75%) in filling the apical lateral canals (P < 0.05). BioRoot RCS was the best sealer to fill coronal lateral canals (3.322 ± 0.085 mm/83.05%).

Conclusion

During the lateral condensation technique, the filling of the lateral canals is affected by the type of root canal sealer and the location of the lateral canals All the sealers tested have a good ability to fill the apical lateral, while BioRoot RCS was effective in filling both the coronal and apical lateral canals.

Discoloration Improvement by Mechanically-Milled Binary Oxides as Radiopacifier for Mineral Trioxide Aggregates

Mineral trioxide aggregates (MTA) have been widely used in endodontic treatments, but after some time, patients suffer tooth discoloration due to the use of bismuth oxide (Bi2O3) as a radiopacifier. Replacement of Bi2O3 with high energy ball-milled single (zirconia ZrO2; hafnia, HfO2; or tantalum pentoxide, Ta2O5) or binary oxide powder was attempted, and corresponding discoloration improvement was investigated in the present study. Bi2O3-free MTA is expected to exhibit superior discoloration. The radiopacity, diametral tensile strength, and discoloration of MTA-like cements prepared from the as-milled powder were investigated. Experimental results showed that MTA-like cements prepared using Ta2O5 exhibited a slightly higher radiopacity than that of HfO2 but had a much higher radiopacity than ZrO2. Milling treatment (30 min to 3 h) did not affect the radiopacities significantly. These MTA-like cements exhibited superior color stability (all measured ΔE00 < 1.0) without any perceptible differences after UV irradiation. MTA-like cements prepared using ZrO2 exhibited the best color stability but the lowest radiopacity, which can be improved by introducing binary oxide. Among the investigated samples, MTA-like cement using (ZrO2)50(Ta2O5)50 exhibited excellent color stability and the best overall performance with a radiopacity of 3.25 mmAl and a diametral tensile strength of 4.39 MPa.

Modified Mineral Trioxide Aggregate—A Versatile Dental Material: An Insight on Applications and Newer Advancements

Mineral Trioxide Aggregate (MTA) has been a material of revolution in the field of dentistry since its introduction in the 1990s. It is being extensively used for perforation repairs, apexification, root-end filling, obturation, tooth fracture repair, regenerative procedures, apexogenesis, pulpotomies, and as a pulp-capping material because of its desired features such as biocompatibility, bioactivity, hydrophilicity, sealing ability, and low solubility. Even though its application is wide, it has its own drawbacks that prevent it from reaching its full potential as a comprehensive replacement material, including a long setting time, discoloration, mud-like consistency, and poor handling characteristics. MTA is a material of research interest currently, and many ongoing studies are still in process. In this review, the newer advancements of this versatile material by modification of its physical, chemical, and biological properties, such as change in its setting time, addressing the discoloration issue, inclusion of antimicrobial property, improved strength, regenerative ability, and biocompatibility will be discussed. Hence, it is important to have knowledge of the traditional and newer advancements of MTA to fulfill the shortcomings associated with the material.

In vitro bioactivity of newly introduced dual-cured resin-modified calcium silicate cement

Background:

This study was designed to investigate the in vitro bioactivity of a new dual cured calcium silicate cement (TheraCal PT) compared to its light cured (TheraCal LC) and chemically set (Biodentine) counterparts.

Materials and Methods:

The study is an in vitro original research article. Prepared cements discs were immersed in deionized water. Ca²+ release was evaluated using inductively coupled plasma-optical emission spectrometry while pH was assessed using a pH meter after 1, 14, and 28 days. Discs for surface characterization were immersed in phosphate-buffered saline (PBS) and were examined using an environmental scanning electron microscope with energy dispersive X-ray (ESEM/EDX), immediately after setting and at 1, 14, and 28 days intervals after that. Attenuated total reflectance (ATR)/Fourier transform infrared (FTIR) and Raman spectroscopy analyses were performed after setting and after 28 days storage in PBS. Statistical analysis was performed using the two-way repeated measure analysis of variance test followed by Bonferroni test for multiple comparisons (P < 0.05).

Results:

Biodentine exhibited the highest mean values for Ca²+ release (792,639,278 ppm) and pH (10.99, 12.7, 11.54) at all time intervals. ESEM/EDX displayed a continuous layer of calcium phosphate formed by Biodentine and TheraCal LC while TheraCal PT developed scarce interrupted precipitates after immersion in PBS. ATR/FTIR and Raman spectroscopy for the formed precipitates confirmed the presence of phosphate and Ca (OH) ₂ in Biodentine, TheraCal LC and TheraCal PT.

Conclusion:

TheraCal PT exhibited limited in vitro bioactivity which may limit its prognosis in clinical applications for vital pulp therapy. TheraCal LC is considered a potential bioactive calcium silicate cement despite its lower Ca²+ release compared to Biodentine. Highest bioactivity was observed in Biodentine.

Chitosan Enhances the Anti-Biofilm Activity of Biodentine against an Interkingdom Biofilm Model

Endodontic infection is a biofilm disease that is difficult to irradicate with current treatment protocols, and as such, persistent micro-organisms may lead to ongoing or recurrent disease. The potential for the use of enhanced filling materials to modify biofilm regrowth is a promising strategy. This current study aimed to evaluate the anti-biofilm efficacy of calcium silicate cements modified with chitosan. The development of mono-species and multi-species biofilms on ProRoot MTA, Biodentine and bovine dentine discs were explored using quantitative microbiology analysis. The effect on regrowth of biofilms was assessed following the addition of chitosan to each cement. In comparison to a dentine substrate, both materials did not show the ability to inhibit biofilm regrowth. Biodentine incorporated with chitosan displayed a dose-dependent reduction in multi-species biofilm regrowth, unlike MTA. Notably, interkingdom biofilms were shown to enhance bacterial tolerance in the presence of chitosan. This study demonstrates the potential to enhance the antimicrobial properties of Biodentine. The findings highlight the need for appropriate model systems when exploring antimicrobial properties of materials in vitro so that interspecies and interkingdom interactions that modify tolerance are not overlooked while still supporting the development of innovative materials.

Investigation of a modified hydraulic calcium silicate-based material - Bio-C Pulpo

This study evaluated the physicochemical, biological, and antimicrobial properties of a new hydraulic calcium silicate-based modified material, and compared it with MTA Repair HP and MTA Angelus. The materials were assessed regarding color luminosity (L), color change, radiopacity, setting time, and ISO 6876:2012 linear flow. Volumetric filling and volume change were evaluated using microcomputed-tomography (µCT). Chemical characterization after 28 days in Hank's Balanced Salt Solution (HBSS) and pH analysis were also assessed. Biological characterization of cytotoxicity and microbiological assessment were also undertaken. Shapiro-Wilk, ANOVA, Levene and post hoc analyses with Bonferroni correction were performed, adopting a 5% significance level (p <0.05). Bio-C Pulpo exhibited the highest L values after 90 days. All tested materials demonstrated color change during the analyses, and had radiopacity above 5 mm Al. MTA Repair HP set faster than Bio-C Pulpo, whereas the latter had the highest linear flow. MTA Repair HP had the highest volumetric filling in µCT analysis. Bio-C Pulpo showed the highest alkalinity during all tested periods, and the highest volumetric loss (above 9%), in comparison with MTA Repair HP and MTA Angelus. Bio-C Pulpo did not form calcium hydroxide after hydration. MTA Repair HP demonstrated the highest cytocompatibility, and Bio-C Pulpo, the highest cytotoxicity. No inhibition halos were observed for any material, and similar higher turbidity values were seen after direct contact. Composition additives used in Bio-C Pulpo modified its properties, and both the absence of calcium hydroxide deposition after hydration, and the related cytotoxicity of this material are of particular concern.

Graphene nanoplatelets embedded polymer: An efficient endodontic material for root canal therapy

The design and preparation of clinically relevant endodontic obturating material for root canal therapy is a great challenge. For the first time, we report a new polymer nanocomposite which was prepared by using reversible addition-fragmentation chain-transfer (RAFT) polymerization of methacrylic acid and methylene glycol dimethacrylate. The polymer was embedded with reduced graphene oxide nanoplatelets (rGO). These graphene nanoplatelets were embedded in the polymers (GNPs) have shown the tensile strength (27--36%) and the elongation at break 2.1 - 3.1% is quite similar to the commercial gutta percha (GP-C). Atomic force micrograph provided interesting information related to scattering of rGO flakes in GNPs and the surface of GNP contains crystalline spikes of height varied between 0.95 and 1.26 μm. These spikes improved the adhesion of GNPs to bio-interface. The GNPs were 95% more effective in inhibiting bacterial colonization without disturbing the nearby cell integrity compared to commercial GP. It was found that the GNPs after incubation of 24 h at 37 °C, the radius of the inhibition zone was 6.8 mm and 4.3 mm for E.coli and S. aureus, respectively indicating better effective antibacterial activity than the GP-C. This work offers biocompatible, better adhesive and antibacterial endodontic obturating material for future root canal therapy.

Antifungal Effectiveness between Tricalcium Silicate-White Portland Cements Added Bi2O3 and Mineral Trioxide Aggregate Against Candida albicans

Background

Candida albicans is the most dominant fungus found in root canal reinfection cases. This microorganism can withstand extreme pH, low oxygen levels, lack of nutrients, and penetrate the dentinal tubules so that it can resist the intracanal medicament. Root canal cement helps prevent microorganisms and causing root canal reinfection. MTA is one of the root canals cement which is widely used and has an excellent antifungal activity, but it is less beneficial economically. Tricalcium silicate-white Portland cement (WPC) has a similar main composition as MTA, except there is no Bi2O3 content that functions as a radiopacifier.

Objectives:

To fabricate a mixture of tricalcium silicate-WPC with Bi2O3 through a simple solution method and investigate antifungal activity's effectiveness between tricalcium silicate-WPC added Bi2O3 and MTA to C. albicans.

Materials and Methods:

The 80 g of tricalcium silicate-WPC was mixed with 20 g of Bi2O3 through the simple solution method using 99.9% isopropanol as a solution. This sample solution is stirred until homogeneous, then centrifuged. The precipitate was dried until a dry powder was obtained. The powder was analyzed using X-Ray fluorescence spectrometry to identify its chemical composition and concentration. A total of 30 samples were divided into two experimental groups of tricalcium silicate-WPC added Bi2O3 and ProRoot MTA. The vials, which contain cement and C. albicans, respectively, were incubated at 37°C for 24 hours and diluted to obtain a suspension 104, 106 (0.5 in McFarland’s nephelometer) and then inoculated with sterile cotton swabs onto Saboroud Dextrose Agar Plates. The plates were incubated at 37°C for 24 hours. The measurement of colony number of C. albicans was counted by colony counter (CFU/ml).

Results:

The Bi2O3 was revealed in tricalcium silicate-WPC based on XRF characterization, and the antifungal test showed that both materials were effective against C. albicans. There was no statistically significant difference in the number of C. albicans colonies between tricalcium-WPC added Bi2O3 and MTA (p>0.05).

Conclusion:

The mixture of Bi2O3 in tricalcium silicate-WPC was successfully fabricated through a simple solution method, and both samples were effective against the C. albicans.

The effect of chlorhexidine and dimethyl sulfoxide on long-term sealing ability of two calcium silicate cements in root canal

OBJECTIVES

To evaluate the long-term effect of chlorhexidine (CHX) and dimethyl sulfoxide (DMSO) on the sealing ability and biomineralization of two different calcium silicate cements (CSC) in root canal.

METHODS

Sixty human third molar root canals were obturated with ProRoot MTA or Biodentine. Before obturation the canals were irrigated with saline (control), 2% CHX or 5% DMSO. Microleakage was tested after three days and after six months. After additional six months (12 months after root filling) the roots were cut into 2 mm thick dentine discs. The discs were stored in artificial saliva for one year. The bond strength was measured with the push-out method, and the failure mode was evaluated with a stereomicroscope. The most apical disc of each tooth was used for Vickers hardness test.

RESULTS

No significant differences between the groups was found in initial microleakage. The leakage increased significantly during the 6-month storage in all groups except in Biodentine-CHX group and Biodentine-DMSO group. CHX and DMSO irrigation significantly increased the leakage with ProRoot MTA with time, but there was no statistically significant difference compared to the ProRoot MTA-control group at six months' time point. CHX significantly reduced the push-out bond strength of ProRoot MTA. With Biodentine irrigation with CHX or DMSO resulted with significantly higher push-out strength compared to the Biodentine control group. Fracture analysis showed statistically significant difference in the distribution of the fractures between the groups, but neither CHX nor DMSO change the fracture pattern statistically significantly. With Vickers hardness test ProRoot MTA with and without DMSO as the final irrigant showed significantly higher dentin hardness than any Biodentine-group.

SIGNIFICANCE

Considering that aging increased the leakage in all groups except with Biodentine-DMSO and the differences in the push-out strength and surface microhardness data, it appears that the time-related biomineralizing effect of MTA and Biodentine does not improve sealing to dentin. CHX significantly reduced ProRoot MTA bond strength and increased pure adhesive failures with both cements.

Effects of Milling Time, Zirconia Addition, and Storage Environment on the Radiopacity Performance of Mechanically Milled Bi2O3/ZrO2 Composite Powders

Mineral trioxide aggregate (MTA) typically consists of Portland cement (75 wt.%), bismuth oxide (20 wt.%), and gypsum (5 wt.%) and is commonly used as endodontic cement. Bismuth oxide serving as the radiopacifying material reveals the canal filling effect after clinical treatment. In the present study, bismuth/zirconium oxide composite powder was prepared by high energy ball milling of (Bi₂O₃)_100−x (ZrO₂)_x (x = 5, 10, 15, and 20 wt.%) powder mixture and used as the radiopacifiers within MTA. The crystalline phases of the as-milled powders were examined by the X-ray diffraction technique. The radiopacities of MTA-like cements prepared by using as-milled composite powders (at various milling stages or different amount of zirconia addition) were examined. In addition, the stability of the as-milled powders stored in an ambient environment, an electronic dry box, or a glove box was investigated. The experimental results show that the as-milled powder exhibited the starting powder phases of Bi₂O₃ and ZrO₂ and the newly formed δ-Bi_7.38Zr_0.62O_2.31 phase. The longer the milling time or the larger the amount of the zirconia addition, the higher the percentage of the δ-Bi_7.38Zr_0.62O_2.31 phase in the composite powder. All the MTA-like cements prepared by the as-milled powder exhibited a radiopacity higher than 4 mmAl that is better than the 3 mmAl ISO standard requirement. The 30 min as-milled (Bi₂O₃)₉₅(ZrO₂)₅ composite powder exhibited a radiopacity of 5.82 ± 0.33 mmAl and degraded significantly in the ambient environment. However, storing under an oxygen- and humidity-controlled glove box can prolong a high radiopacity performance. The radiopacity was 5.76 ± 0.08 mmAl after 28 days in a glove box that was statistically the same as the original composite powder.

The role of calcium ion release on biocompatibility and antimicrobial properties of hydraulic cements

Tricalcium silicate (TCS)-based materials produce calcium hydroxide as a byproduct of their hydration reaction. The present study investigated whether calcium ion release (CIR) affects their biological and antimicrobial properties when used as pulp protection materials. The effect of incorporation of micro-silica and calcium phosphate monobasic to radiopacified TCS-based materials was investigated. The commercial TCS-based Biodentine, Bio-C Pulpo, TotalFill Root Repair Material, TheraCal LC and a base/liner- ACTIVA BioACTIVE (Activa) were also evaluated. The hydration and CIR were monitored and correlated with biocompatibility and antimicrobial assessment of eluates. Overall, the additives altered the hydration and leaching profile of the prototype cements. The micro-silica inclusion resulted in a decreased long-term calcium hydroxide formation which was associated with neutralised cytotoxicity and antibacterial activity. Calcium phosphate did not alter the leaching profile, although a stronger antibacterial effect was induced. The commercial materials also had different CIR profiles. The water-based ones had higher CIR, and this was associated with stronger antimicrobial effect but not enhanced biological activity. Both TheraCal LC and Activa exhibited poor degree of conversion, low CIR, acceptable biocompatibility and moderate antibacterial activity. A positive correlation of CIR with antibacterial effectiveness was observed (0.3 < r < 0.49; p = 0.021, p = 0.011 for the two test bacterial cultures). No relation was shown between CIR and cytotoxicity (0.3 < r < 0.49; p = 0.150, p = 0.068 for the two cell cultures studied). The additives modified the CIR. The antimicrobial properties were dependent on the CIR; the cytotoxicity of the materials was unaffected.

Biodentine™ Partial Pulpotomy of a Young Permanent Molar with Signs and Symptoms Indicative of Irreversible Pulpitis and Periapical Lesion: A Case Report of a Five-Year Follow-Up

The purpose of this paper was to report the five-year success of Biodentine™ partial pulpotomy in a young permanent molar, with signs and symptoms indicative of irreversible pulpitis and periapical lesion, in a nine-year-old girl. Preoperative clinical examination revealed a large carious lesion of the left mandibular permanent first molar. The patient reported pain on percussion. The tooth responded positively to the electric pulp test and had lingering pain after cold testing. A periapical radiograph showed a deep carious lesion and periapical lesion. Based on the clinical and radiographical examination, the tooth had signs and symptoms indicative of irreversible pulpitis and periapical lesion. During caries removal, pulp exposure occurred, and 2-3 mm in depth of pulp tissue at the exposure site was removed. Haemorrhage was controlled within four minutes with 2.5% sodium hypochlorite-moistened cotton pellets. Biodentine™ was then applied as both a pulp dressing and a temporary restoration. At the following visit, composite resin was placed over the Biodentine™ as a final restoration. During a five-year follow-up, the tooth was asymptomatic, had positive responses to sensibility tests, and had no discolouration. Follow-up radiographs showed a dentine bridge and periapical healing.

Periradicular inflammatory response, bone resorption, and cementum repair after sealing of furcation perforation with mineral trioxide aggregate (MTA Angelus™) or Biodentine™

OBJECTIVE

This study assessed tissue responses after furcation perforation and immediate sealing with either Biodentine™ or MTA Angelus™.

MATERIAL AND METHODS

Sixty male Wistar rats were used (n = 6 per group/period). The mandibular first molars had the furcation mechanically exposed and sealed with either MTA or Biodentine™ and restored with silver amalgam. In an additional test group, teeth were sealed only with Biodentine™. Furcation sealing with gutta-percha and silver amalgam restoration served as positive control, and healthy untreated teeth were the negative control. Histological evaluation was performed after 14 or 21 days. Kruskal-Wallis and Dunn's post hoc tests were performed to analyze the extent and intensity of tissue inflammation, bone resorption, and cementum repair (p < 0.05).

RESULTS

Biodentine™ and MTA presented satisfactory results, showing a milder inflammatory response when compared to the control, regardless of the material used for coronal sealing and of the experimental period evaluated (p < 0.0001). All test groups showed less bone resorption than the positive control after 21 days (p < 0.05), and such differences were more pronounced in teeth restored with silver amalgam. Cementum repair was performed in 30% of MTA and Biodentine™ samples but not carried out in any positive control specimen.

CONCLUSIONS

Biodentine™ and MTA promoted similar responses when used to seal furcation perforations and should therefore be regarded as a promising alternative.

CLINICAL RELEVANCE

Knowledge about tissue responses to restorative materials is essential for improving root perforation sealing protocols. The present results showed that both Biodentine™ and MTA promoted appropriate periradicular tissue reactions in a preclinical test for evaluating furcation perforation treatments.

Partial pulpotomy with two bioactive cements in permanent teeth of 6- to 18-year-old patients with signs and symptoms indicative of irreversible pulpitis: a noninferiority randomized controlled trial

AIM

To compare the outcome of partial pulpotomy using two cements, ProRoot MTA (Dentsply, Tulsa Dental Specialties, Tulsa, OK, USA) and Biodentine (Septodont, Saint-Maur-des-Fossés, France), in permanent teeth of 6- to 18-year-old patients with signs and symptoms indicative of irreversible pulpitis. Furthermore, the frequencies of perceptible grey discoloration caused by the cements were compared.

METHODOLOGY

Sixty-nine permanent first molars with signs and symptoms indicative of irreversible pulpitis, from 69 patients, were included. All operators performed partial pulpotomy under a standardized protocol. Teeth were allocated, using a website-generated number of simple randomization, to partial pulpotomy with either ProRoot MTA (37 teeth) or Biodentine (32 teeth) and were restored with composite resin or stainless steel crowns. Patients were recalled every 6 months. To be categorized as having success, the evaluated tooth must have had both clinical and radiographic success. In addition, photographs of treated teeth were evaluated for frequency of perceptible grey discoloration. Success rates between the two cements were compared using the Fisher exact test. The frequencies of perceptible grey discoloration were compared using the chi-square test. The percentage difference was estimated by 95% confidence interval, and the level of significant difference was P < 0.05.

RESULTS

At a mean follow-up of 32.2 ± 17.9 months, a total of 67 teeth, 37 with ProRoot MTA and 30 with Biodentine, were available for evaluation. The mean age of participants was 10 ± 2.1 years and, there were no differences in the baseline variables (gender, age, tooth type, periapical status, stage of root development, final restoration and follow-up period) between the groups. The overall success in both groups was 90%, with 92% for ProRoot MTA and 87% for Biodentine (difference, 5%; 95% confidence interval, -9% to 19%, P = 0.487), suggesting that Biodentine was noninferior to ProRoot MTA. Perceptible grey discoloration was observed in both groups, 80% for teeth treated with ProRoot MTA and 27% for teeth treated with Biodentine, with a significant difference between the materials (P < 0.001).

CONCLUSIONS

Permanent teeth with signs and symptoms indicative of irreversible pulpitis in 6- to 18-year-old patients were successfully treated with partial pulpotomy using both cements. Biodentine exhibited significantly less frequency of discoloration than did ProRoot MTA.

The use of Bioceramics as root-end filling materials in periradicular surgery: A literature review

Introduction

Periradicular surgery involves the placement of a root-end filling following root-end resection, to provide an apical seal to the root canal system. Historically several materials have been used in order to achieve this seal. Recently a class of materials known as Bioceramics have been adopted. The aim of this article is to provide a review of the outcomes of periradicular surgery when Bioceramic root-end filling materials are used on human permanent teeth in comparison to "traditional" materials.

Methods & results

An electronic literature search was performed in the databases of Web of Science, PubMed and Google Scholar, between 2006 and 2017, to collect clinical studies where Bioceramic materials were utilised as retrograde filling materials, and to compare such materials with traditional materials. In this search, 1 systematic review and 14 clinical studies were identified. Of these, 8 reported the success rates of retrograde Bioceramics, and 6 compared treatment outcomes of mineral trioxide aggregate (MTA) and traditional cements when used as root-end filling materials.

Conclusion

Bioceramic root-end filling materials are shown to have success rates of 86.4-95.6% (over 1-5 years). Bioceramics has significantly higher success rates than amalgam, but they were statistically similar to intermediate restorative material (IRM) and Super ethoxybenzoic acid (Super EBA) when used as retrograde filling materials in apical surgery. However, it seems that the high success rates were not solely attributable to the type of the root-end filling materials. The surgical/microsurgical techniques and tooth prognostic factors may significantly affect treatment outcome.

Cell Viability and Tissue Reaction of NeoMTA Plus: An In Vitro and In Vivo Study

INTRODUCTION

The aim of this study was to evaluate the cell viability and tissue reaction of NeoMTA Plus (NMP; Avalon Biomed Inc, Houston, TX) compared with mineral trioxide aggregate (MTA; Angelus, Londrina, PR, Brazil) and Biodentine (BD; Septodont, Saint-Maur-de-Fossés, France).

METHODS

Fibroblasts (3T3) were plated and exposed to 1% extract from the test material before and after setting. Cytotoxicity assessment was performed using the 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide and sulforhodamine B assays. In vivo evaluation consisted of polyethylene tube implantation of the materials in rat subcutaneous tissue. Histologic analysis occurred at 7, 30, and 90 days, scoring inflammatory events and collagen fiber formation. Analysis of variance and the Tukey and t tests were used for cytocompatibility assays, and the Kruskal-Wallis test followed by the Dunn test were used for biocompatibility assays (P ≤ .05).

RESULTS

The materials in the cytotoxicity assays presented greater viability after setting (P ≤ .05). NMP and MTA presented higher viability than the control (Dulbecco modified Eagle medium) on the 3-(4,5-dimethyl-thiazoyl)-2,5-diphenyl-tetrazolium bromide assay before and after setting (P ≤ .05). The sulforhodamine B assay showed that MTA and BD presented less viability than NMP and the control, and NMP was similar to the control before setting. After setting, MTA and BD presented higher viability when compared with the control group (P ≤ .05), and NMP was similar to control. Inflammatory infiltrate reduction occurred throughout the test periods for all materials. At 7 days, neutrophils were present in BD (P ≤ .05), and granuloma and giant cells were present in BD and MTA. At 30 days, BD showed intense inflammatory infiltrates and a large number of macrophages when compared with NMP, MTA, and the control (P ≤ .05). At 90 days, BD presented a thick fiber layer compared with NMP (P ≤ .05).

CONCLUSIONS

NMP showed similar biocompatible behavior to MTA and BD.

Novel Calcium Zirconate Silicate Cement Biomineralize and Seal Root Canals

This study evaluated the sealing ability of gutta-percha (GP) with a calcium silicate-based sealer and a novel calcium zirconate containing calcium silicate cement (ZC). The root canals of the extracted premolars were prepared, which were then randomly allocated to three experimental groups (12 root canals per group) for obturation by continuous wave of condensation with the GP and AH 26 sealer (CW); obturation using a single GP with a calcium silicate-based EndoSequence BC sealer (SC); or obturation with ZC. The roots were inserted into sterile Eppendorf tubes, which were inoculated coronally with Porphyromonas gingivalis. The amount of endotoxin leakage into the apical reservoirs were measured using the Limulus Amebocyte Lysate (LAL) assay over 21 days, with comparisons made using one-way ANOVA and Scheffe’s tests (α = 0.05). After 21 days, 75% of the canals that had been obturated by SC, 50% of those obturated by CW and 42% of those obturated by ZC showed endotoxin leakage. The amount of leakage was higher in the SC canals than in the CW (p = 0.031) or ZC (p = 0.03) canals, although there was no significant difference in the amount of leakage for CW and ZC (p > 0.05). X-ray diffraction revealed the presence of tricalcium silicate (Ca₃SiO₅) and calcium zirconate (CaZrO₃) in the synthesized ZC. Scanning electron microscopy revealed mineralized precipitates on the dentin of canals obturated by ZC. The novel calcium zirconate silicate cement appears to promote biomineralization and seal root canals at least as effectively as the conventional sealer.

Biocompatibility and biomineralization assessment of mineral trioxide aggregate flow

OBJECTIVE

Evaluate, in vivo, the biocompatibility via subcutaneous inflammatory tissue response and mineralization ability of the new MTA Flow compared to MTA Angelus and ProRoot MTA.

MATERIALS AND METHODS

Forty male Wistar rats were assigned and received subcutaneous polyethylene tube implants containing the test materials and a control group with empty tube (n = 10 animals/group). After days 7, 15, 30, and 60, the animals were euthanized and the polyethylene tubes were removed with the surrounding tissues. Inflammatory infiltrate and thickness of the fibrous capsule were histologically evaluated. Mineralization was analyzed by Von Kossa staining and under polarized light. Data were analyzed via Kruskal-Wallis and Dunn's test with a significance level of 5%.

RESULTS

MTA Angelus induced the mildest reaction after 7 (P > .05) and 15 days (P < .05) followed by MTA Flow, both cements achieving mild inflammatory reaction after 15 days. ProRoot MTA induced a severe inflammation on day 7 and was reducing after day 15 (P > .05). No difference was observed after days 30 or 60 (P > .05). Von Kossa staining and birefringent structures were positive to all materials.

CONCLUSIONS

At the end of the experiment, the novel MTA Flow showed biocompatibility and induced biomineralization in all time periods.

CLINICAL RELEVANCE

The final consistence obtained in MTA Flow may facilitate several procedures, indicating that the MTA Flow has a promising application in endodontics.

Innovative root-end filling materials based on calcium-silicates and calcium-phosphates

This in vitro study evaluated the apical sealing ability, bioactivity and biocompatibility of an experimental calcium silicate-based and two light-curing calcium silicate/calcium-phosphate cements as potential root end filling materials. A calcium silicate Portland-based (Control PC), an experimental calcium silicate (Exp. PC) and two light-curing cements (LC-CaP; LC-Si/CaP) were assessed for their alkalinising activity (pH) and biocompatibility. Single-rooted human canines were endodontically treated, filled with gutta-percha and finally submitted to apicoectomy. Root end fillings were performed using all tested cements, and their apical sealing ability was evaluated up to 4 weeks of immersion in simulated body fluid (SBF). The mineral precipitation at the apical region and the cement adaptation to root dentine were also evaluated through non-destructive optical microscopy both at 24 h and after prolonged water storage (four week). LC-CaP and LC-Si/CaP had neutral pH, the greatest sealing ability (24 h) and excellent cytocompatibility. The Exp. PC cement presented sealing ability after two and four weeks, as well as biocompatibility after four and seven days, similar to LC-CaP and LC-Si/CaP. The control PC cement showed the lowest sealing ability and the greatest cytotoxicity. Mineral precipitation was observed in all groups, while some differences were seen in terms of cement adaptation along the root canal dentine walls. The experimental light-curable cements as well as the experimental PC might be suitable root end filling materials with appropriate (in vitro) sealing ability, biocompatibility and aptitude to induce mineral precipitation.

Evaluation of the Ca ion release, pH and surface apatite formation of a prototype tricalcium silicate cement

AIM

To evaluate the Ca²⁺ -releasing, alkalizing and apatite-like surface precipitate-forming abilities of a prototype tricalcium silicate cement, which was mainly composed of synthetically prepared tricalcium silicate and zirconium oxide radiopacifier.

METHODOLOGY

The prototype tricalcium silicate cement, white ProRoot MTA (WMTA) and TheraCal LC (a light-cured resin-modified calcium silicate-filled material) were examined. The chemical compositions were analysed with a wavelength-dispersive X-ray spectroscopy electron probe microanalyser with an image observation function (SEM-EPMA). The pH and Ca²⁺ concentrations of water in which the set materials had been immersed were measured, and the latter was assessed with the EDTA titration method. The surface precipitates formed on the materials immersed in phosphate-buffered saline (PBS) were analysed with SEM-EPMA and X-ray diffraction (XRD). Kruskal-Wallis tests followed by Mann-Whitney U-test with Bonferroni correction were used for statistical analysis (α = 0.05).

RESULTS

The prototype cement contained Ca, Si and Zr as major elemental constituents, whereas it did not contain some metal elements that were detected in the other materials. The Ca²⁺ concentrations and pH of the immersion water samples exhibited the following order: WMTA = prototype cement > TheraCal LC (P < 0.05). All three materials produced Ca- and P-containing surface precipitates after PBS immersion, and the precipitates produced by TheraCal LC displayed lower Ca/P ratios than those formed by the other materials. XRD peaks corresponding to hydroxyapatite were detected in the precipitates produced by the prototype cement and WMTA.

CONCLUSION

The prototype tricalcium silicate cement exhibited similar Ca²⁺ -releasing, alkalizing and apatite-like precipitate-forming abilities to WMTA. The Ca²⁺ -releasing, alkalizing and apatite-like precipitate-forming abilities of TheraCal LC were lower than those of the other materials.