The setting characteristics of MTA Plus in different environmental conditions

Comparative Evaluation of Sealing Ability of Different Type of MTA as Root-End Filling Materials Using Dye Penetration Technique - An In Vitro Study

Introduction

The main goal of the root-end filling material is to create a hermetic seal to protect against microbes and their by-products. Excellent biocompatibility and sealing ability are characteristics of MTA developed by Torabinejad et al. This study aimed to compare the sealing ability of different type MTA as root-end filling material using dye penetration technique.

Material and Method

One-twenty (N = 120) extracted human maxillary anterior teeth were decontaminated, cleaned, and decoronated. Endodontic treatment and root-end resection were done. Then root-end cavity was prepared and filled with tested materials (N = 30). A calibrated stereomicroscope was used to evaluate linear measurement. All data were tabulated and statistically analyzed with a level of significance set at P < .05.

Result

This order of increasing microleaks was observed: MTA Angelus < MTA Plus < PRO-Root MTA < Control group. There was a statistically significant difference in mean microleakage in MTA Angelus and MTA Plus groups (P = 0.040). MTA Angelus shows the least microleakage among all the bioceramic material groups.

Conclusion

Although the sealing ability of MTA Angelus is superior to MTA Plus, PRO-Root MTA. MTA Plus, PRO-Root MTA could be considered an acceptable alternative to MTA Angelus in peri-radicular surgeries.

Delayed vs. immediate placement of restorative materials over Biodentine and RetroMTA: a micro-shear bond strength study

BACKGROUND

The aim of the present study was to investigate the micro-shear bond strength (µSBS) of various restorative materials applied on two different fast-setting calcium silicate-based materials and to evaluate the effect of restoration time on µSBS.

METHODS

A total of 180 acrylic blocks with a cavity in the center were randomly divided into 2 main groups according to the capping material to be used (Biodentine or RetroMTA). The specimens were also randomly divided into 3 groups according to the restoration time (3 min, 12 min, 24 h). After the specified waiting periods, glass hybrid material (EQUIA Forte HT), resin composite (Filtek Z550) and light-cured calcium silicate material (Theracal LC) were placed on the specimens with tygon tubes. The specimens were kept for 24 h and then subjected to µSBS test. Statistical analysis was performed by 3-way ANOVA followed by Tukey test for pairwise comparisons (α = 0.05).

RESULTS

There is a statistically significant difference (p < 0.05) between the µSBS values obtained by applying resin composite on RetroMTA after different setting times (24 h > 12 min > 3 min). The µSBS obtained for the Biodentine-resin composite at the end of the 3 min setting time is significantly lower (p < 0.05) than the µSBS values at 12 min and 24 h. For both calcium silicate cements, at the end of all time periods, the µSBS obtained when resin composite was applied at the end was higher than the other materials (p < 0.05).

CONCLUSIONS

For Biodentine-resin composite bonding, the manufacturer's recommendation of 12 min can be considered an appropriate time, whereas for RetroMTA-resin composite bonding, the µSBS increased as the waiting time increased. Regardless of the waiting time, it is recommended to prefer direct composite resin restoration over Biodentine and RetroMTA.

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.

Calcium Silicate-Based Sealer Dentinal Tubule Penetration-A Systematic Review of In Vitro Studies

The aim of this systematic review was to perform a qualitative synthesis of in vitro studies which evaluate and compare the penetration of calcium silicate-based sealers into dentinal tubules. A systematic advanced search was performed in Scopus, Embase, Medline (via PubMed), Web of Science, and Cochrane databases on the 1 December 2022. In vitro studies that compared the tubular penetration of at least two calcium silicate-based sealers in extracted human teeth were eligible. PRILE 2021 guidelines were used for the assessment of the risk of bias included studies. The search identified a total of 680 preliminary records, among which 12 studies were eligible for review. The most used methodology to evaluate sealer penetration was the use of a fluorochrome together with the tested sealers and the analysis of their penetration under confocal laser microscopy. Regarding the results of the included studies, calcium silicate-based sealers exhibit a favorable dentinal tubule penetration. Tubular penetration, however, can be affected by factors such as the irrigation protocol, sealer activation, the filling method used, and root canal morphology. EndoSequence BC Sealer showed the highest sealer penetration among the tested sealers. The influence of different fluorochromes on the results of dentinal tubule penetration studies should also be further explored. The in vitro nature of the included studies limits the applicability of the results into the clinical setting. Prospero registration: CRD42022383896.

Alkalizing Properties of Six Calcium-Silicate Endodontic Biomaterials

INTRODUCTION

Calcium silicate-based cements (CSC), are self-setting hydraulic biomaterials widely used for reparative procedures in dentistry and endodontics. These materials possess physical properties, such as ion release, porosity, solubility, and radiopacity. Their biological properties are connected to their alkalizing activity and calcium release capacity.

MATERIALS AND METHODS

Six calcium silicate-based materials were selected for this study: TheraCal LC (Bisco Inc., Schaumburg, IL, USA), MTA Plus (PrevestDenpro, Jammu, India Avalon Biomed Inc., Bradenton, FL, USA), Biodentine (Septodont, Saint-Maur-des-Fossés, France), RetroMTA (BioMTA, Seoul, Korea), MTA Flow (Ultradent Products, Inc., South Jordan, UT, USA), and OrthoMTA (BioMTA, Seoul, Korea). The pH was analyzed immediately after immersion (baseline) and after 1 h, 3 h, 1 day, 2 days, 3 days, 1 week, 2 weeks, 3 weeks, and 1 year with a pH meter, previously calibrated with solutions of known pH. All testing materials had alkaline pH.

RESULTS

Analysis of the tested materials showed statistically significant differences in terms of pH changes as a function of the time showed a gradual rise in the pH of all materials.

CONCLUSIONS

All tested materials exhibited continuous hydroxyl ion release resulting in a rise in pH until the end of time of experience.

A Breakthrough in the Era of Calcium Silicate-Based Cements: A Critical Review

Calcium silicate-based cements (CSCs) or mineral trioxide aggregate (MTA) lookalike materials are blocks of cement or root canal sealers produced from calcium (Ca) and silicate. They have superior sealing ability, bioactivity, and marginal adaptability, making them appropriate for various dental treatment applications. Mineral trioxide aggregate is widely used in numerous endodontic repair techniques. The capacity of this cement to promote tissue regeneration and stimulate mineralization accounts for its widespread usage in pulp capping, apexification, apical surgeries, and revascularization. Several studies have been conducted to investigate changes in the components of MTA-based types of cement directed to improve their presentation clinically. To improve flowability, new Ca silicate-based formulations have been introduced commercially. In these new formulations, essential features such as adequate radiopacity and setting time, color stability, alkaline pH, and calcium ion release and biocompatibility must be considered. Owing to an increased range of indications of CSCs, including some for restorative dentistry, and with the emergence of novel silicate calcium-based materials with considerable changes in their compositions, it is necessary to examine the available scientific literature that evaluates their usage in these applications. Therefore, this review paper aims to assess the existing knowledge of CSCs, emphasizing their potential uses in restorative and endodontic dentistry. This report strives to update doctors' understanding of CSCs, allowing for a better therapeutic approach.

Present status and future directions: Hydraulic materials for endodontic use

BACKGROUND

Hydraulic materials are used in Endodontics due to their hydration characteristics namely the formation of calcium hydroxide when mixing with water and also because of their hydraulic properties. These materials are presented in various consistencies and delivery methods. They are composed primarily of tricalcium and dicalcium silicate, and also include a radiopacifier, additives and an aqueous or a non-aqueous vehicle. Only materials whose primary reaction is with water can be classified as hydraulic.

OBJECTIVES

Review of the classification of hydraulic materials by Camilleri and the literature pertaining to specific uses of hydraulic cements in endodontics namely intra-coronal, intra-radicular and extra-radicular. Review of the literature on the material properties linked to specific uses providing the current status of these materials after which future trends and gaps in knowledge could be identified.

METHODS

The literature was reviewed using PUBMED, and for each clinical use, the in vitro properties such as physical, chemical, biological and antimicrobial characteristics and clinical data were extracted and evaluated.

RESULTS

A large number of publications were retrieved for each clinical use and these were grouped depending on the property type being investigated.

CONCLUSIONS

The hydraulic cements have made a difference in clinical outcomes. The main shortcoming is the poor testing methodologies employed which provide very limited information and also inhibits adequate clinical translation. Furthermore, the clinical protocols need to be updated to enable the materials to be employed effectively.

Hydration Characterization of Two Generations of MTA-Based Root Canal Sealers

Since the setting characterization of a root canal sealer has an impact on its biological behavior of final obturation, this study evaluated the setting characterization of mineral trioxide aggregate MTA-Fillapex versus MTA-Bioseal compared with epoxy resin (Adseal) root canal sealers. Freshly mixed sealer was inserted into the mold (n = 10). The initial and final setting times were evaluated using a Vicat needle and were then statistically analyzed by one-way ANOVA at p < 0.05. The raw pastes and the stages of the setting reaction were analyzed using Fourier Transform Infrared (FTIR) Spectroscopy. The phase compositions were evaluated using X-ray diffraction (XRD). A significant and fast setting time was recorded by Adseal (4.7 ± 0.46 h) followed by MTA-Bioseal (11.4 ± 1.34 h) at p < 0.001. The MTA-Fillapex did not set completely in three months. The FTIR and XRD of both MTA-Bioseal and Adseal detected bands of the polymerized phases, while those of MTA-Fillapex detected partial polymerization with a low percentage of polymerized silica. MTA-Bioseal and Adseal met the ISO standards for setting times. However, MTA-Fillapex did not fulfill the ideal requirement for the sealer. Although the raw pastes of both MTA-sealers had nearly similar compositions, they behaved differently during the hydration reaction. MTA-Bioseal set completely, while MTA-Fillapex was not completely set.

Evaluation of pH, Calcium Ion Release, and Dimensional Stability of an Experimental Silver Nanoparticle-Incorporated Calcium Silicate-Based Cement

An experimental calcium silicate-based root-end filling material incorporated with silver nanoparticles intended for use in periapical surgeries was developed with the purpose to overcome the drawbacks of existing materials and to satisfy the ideal requirements of root-end filling materials. This study was designed to evaluate the physicochemical properties, pH, calcium ion release, and dimensional stability of the experimental cement, and compare the results with commercially available ProRoot MTA (Dentsply). An independent sample test was used to analyze the data. Mean initial pH (immediately after mixing) of the experimental cement was 10.42 ± 0.04 which was higher than that of MTA. However, there was a significant increase in pH of MTA at 1 day, 2 days, and 7 days. Presence of calcium chloride favored the release of calcium ions which was significantly increased in the experimental group at 24 hours. At the end of 30 days, MTA showed a significant expansion when compared to the experimental cement (p < 0.001). In conclusion, the experimental nanoparticle-incorporated calcium silicate-based cement showed clinically acceptable physicochemical properties.

In-vitro evaluation of microleakage of bioceramic root-end filling materials: A spectrophotometric study

Aim

To evaluate the microleakage of newer bioceramic root-end filling materials.

Material and method

Sixty freshly extracted human single-rooted mandibular premolar teeth were selected for the study. Teeth with fractured root, cracks, anddilacerations were rejected. All teeth were cleaned with ultrasonic scalers. Standard access opening was done and root canal treatment was performed with rotary files followed by obturation. After storing in saline for a week apical 3 ​mm of the root was resected at 900 angles to the long axis of the root. Retro cavity preparation was done with ultrasonic tips. The teeth were divided into four groups of 15 specimens each. Group I - Biodentin, GroupII-Bioaggregate, Group III - MTA Plus, and Group IV - MTA. After the restoration of retro cavities of all the teeth as per manufacture instructions, two coats of nail varnish were applied to leave apical 3 ​mm. All teeth were stored in 2% methylene blue for 72 ​h followed by emersion in 65% nitric acid for the next 72 ​h for Dye extraction. The obtained supernatant solution was then centrifuged and optical density or absorbance was measured with a UV spectrophotometer.

Result

Microleakage was found to be increasing in this order: Biodentin ​< ​Bioaggregate ​< ​MTA Plus ​< ​MTA. No significant difference was found in the microleakage of Biodentin compared to that of Bioaggregate(p ​> ​0.01).

Conclusion

All materials exhibit some amount of microleakage. Biodentin shows the least microleakage among all the bioceramic material groups. Hence, Biodentin and bioaggregate are better material of choice for the retrograde filling to prevent microleakage.

Physical, Chemical, Mechanical, and Biological Properties of Four Different Commercial Root-End Filling Materials: A Comparative Study

Commercial mineral trioxide aggregate (MTA) materials such as Endocem MTA (EC), Dia-Root Bio MTA (DR), RetroMTA (RM), and ProRoot MTA (PR) are increasingly used as root-end filling materials. The aim of this study was to assess and compare the physicochemical and mechanical properties and cytotoxicity of these MTAs. The film thicknesses of EC and DR were considerably less than that of PR; however, RM’s film thickness was greater than that of PR. In addition, the setting times of EC, DR, and RM were shorter than that of PR (p < 0.05). The solubility was not significantly different among all groups. The three relatively new MTA groups (EC, DR, and RM) exhibited a significant difference in pH variation and calcium ion release relative to the PR group (p < 0.05). The radiopacity of the three new MTAs was considerably less than that of PR. The mechanical strength of RM was not significantly different from that of PR (p > 0.05); however, the EC and DR groups were not as strong as PR (p < 0.05). All MTA groups revealed cytocompatibility. In conclusion, the results of this study confirmed that EC, RM, DR, and PR exhibit clinically acceptable physicochemical and mechanical properties and cell cytotoxicity.

Effect of surface treatments on push-out bond strength of calcium silicate-based cements to fiber posts

BACKGROUND

To evaluate the effect of surface treatments on the push-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA) to fiber posts.

METHODS

Two brands of fiber posts were used: Reblida post; RP and RelyX post; RX. Each type of post (n = 80/group) was divided into four groups (n = 20/group) and exposed to surface treatment as follows: Control (no treatment), sandblasting (SB), hydrofluoric acid (HF), and TiF₄ 4 wt/v%. Each group was further subdivided into two subgroups (n = 10/subgroup) based on the type of CSCs used as follows: Subgroup A: BD and Subgroup B: WMTA. Push-out bond strength of BD and WMTA to glass fiber posts was assessed. Data were statistically analyzed using three-way ANOVA and Tukey's test. A Weibull analysis was performed on the push-out bond strength data.

RESULTS

BD showed higher bond strength than WMTA (P < 0.001). The push-out bond strength for posts treated with TiF4 4 wt/v% showed greater bond strength than the other surface treatments (P < 0.05). The BD/RP-TiF₄ 4 wt/v% showed the greater characteristic bond strength (σ₀) (15.93) compared with the other groups. Surface treatments modified the surface topography of glass fiber posts.

CONCLUSIONS

The BD/RP-TiF₄ 4 wt/v% showed greater bond strength compared with the other groups. The TiF₄ 4 wt/v% surface treatment enhanced the bond strength of BD and WMTA to glass fiber posts than the other treatments. Surface treatment of fiber post with TiF₄ 4 wt/v% could be used to improve the bond strength with calcium silicate-based cements.

Physicochemical parameters - hydration performance relationship of the new endodontic cement MTA Repair HP

Background

To characterize the chemical composition and textural parameters of the MTA Repair HP precursor powder and their influence to hydration performance.

Material and Methods

Un-hydrated precursor material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence (XRF), laser diffraction (LD), N2 physisorption and field emission gun scanning electron microscopy (FEG-SEM). Setting time was assessed according to ASTM specification C 266. Hydrated material was analysed by XRD, FT-IR, energy dispersive X-ray (EDX) analysis and FEG-SEM.

Results

Ca3SiO5 and Ca2SiO4, in addition to CaWO4 as radiopacifier are the main compositional phases. Other measured parameter indicates high specific surface area of 4.8 m2 g-1, high aluminium content of 1.7 wt.% and low initial and final setting times of 12 and 199 min, respectively. Singular microstructural features consisting of high aspect ratio nanoparticles are main constituents of un-hydrated precursor. Besides, FEM-SEM observation shows notably growth of hexagonal shaped plate-like morphologies homogeneously distributed along the sample during hydration process.

Conclusions

The short setting time measured for HP Repair, is correlated with high surface area of precursor powder, high Al content and the absence of compositional sulphate phases.

Key words:Bioactive endodontic cements, hydration performance, MTA HP Repair, physicochemical parameters.

Influence of photobiomodulation therapy on root development of rat molars with open apex and pulp necrosis

This study aimed to evaluate the role of photobiomodulation (PBM) in apexification and apexogenesis of necrotic rat molars with an open apex. Rat molars were exposed to the oral environment for 3 weeks. Canals were rinsed with 2.5% NaOCl and 17% EDTA, filled with antibiotic paste and sealed. After 7 days, canals were rinsed and divided into six groups (n=6): mineral trioxide aggregate (MTA); blood clot (BC); human dental pulp stem cells (hDPSC); MTA+PBM; BC+PBM; and hDPSC+PBM. In hDPSC groups, a 1% agarose gel scaffold was used. Two groups were not exposed: healthy tooth+PBM (n = 6), healthy tooth (n = 3); and one was exposed throughout the experiment: necrotic tooth (n = 3). In PBM groups, irradiation was performed with aluminum gallium indium phosphide (InGaAlP) diode laser for 30 days within 24-h intervals. After that, the specimens were processed for histological and immunohistochemical analyses. Necrotic tooth showed greater neutrophil infiltrate (p < 0.05). Necrotic tooth, healthy tooth, and healthy tooth+PBM groups showed absence of a thin layer of fibrous condensation in the periapical area. All the other groups stimulated the formation of a thicker layer of fibers (p < 0.05). All groups formed more mineralized tissue than necrotic tooth (p < 0.05). PBM associated with MTA, BC, or hDPSC formed more mineralized tissue (p < 0.05). MTA+PBM induced apexification (p < 0.05). Rabbit polyclonal anti-bone sialoprotein (BSP) antibody confirmed the histological findings of mineralized tissue formation, and hDPSC groups exhibited higher percentage of BSP-positive cells. It can be concluded that PBM improved apexification and favored apexogenesis in necrotic rat molars with an open apex.

Histology of NeoMTA Plus and Quick-Set2 in Contact with Pulp and Periradicular Tissues in a Canine Model

INTRODUCTION

NeoMTA Plus (Avalon Biomed Inc, Bradenton, FL) is a tricalcium silicate material similar to the first mineral trioxide aggregate product, ProRoot MTA (Dentsply Sirona, York, PA), but with improvements such as decreased setting time, increased ion release, increased water sorption, and nonstaining radiopacifiers. Quick-Set2 (Avalon Biomed Inc) is a newly formulated calcium aluminosilicate material that has a faster setting time and increased acid resistance and is nonstaining. The purpose of this study was to compare the healing of pulpal and periapical tissues in dogs after exposure to NeoMTA Plus and Quick-Set2 after pulpotomy and root-end surgery procedures.

METHODS

Seventy-two teeth (36 for each procedure) in 6 beagle dogs received pulpotomy or root-end surgery using either NeoMTA Plus or Quick-Set2. The dogs were sacrificed at 90 days, and the teeth and surrounding tissues were prepared for histologic evaluation. Sixty teeth were evaluated and scored histologically (29 with pulpotomies and 31 with root-end resections). Specimens were scored for inflammation, quality and thickness of dentin bridging, pulp tissue response, cementum and periodontal ligament formation, and apical bone healing.

RESULTS

Both materials displayed favorable healing at 90 days. The only significant difference was the quality of dentin bridge formation in pulpotomies using NeoMTA Plus compared with Quick-Set2.

CONCLUSIONS

Quick-Set2 and NeoMTA Plus had similar effects on inflammation, pulp response, periodontal ligament and cementum formation, and apical tissue healing in dogs. NeoMTA Plus had superior dentin bridge quality compared with Quick-Set2.

Biological effects of acid-eroded MTA Repair HP and ProRoot MTA on human periodontal ligament stem cells

OBJECTIVE

The aim of this study was to analyze the biological effects of MTA Repair HP and ProRoot MTA on human periodontal ligament stem cells (hPDLSCs) after exposure to acidic and neutral environments.

MATERIALS AND METHODS

Discs of each material (n = 30) were exposed to phosphate buffered saline (pH = 7.4) or butyric acid (pH = 5.2) for 7 days, and biological testing was carried out in vitro on hPDLSCs. Cell viability and apoptosis assays were performed using eluates of each root-end filling material. To evaluate cell attachment to the different materials, hPDLSCs were directly seeded onto the material surfaces and analyzed by scanning electron microscopy. The chemical composition of the root-end filling materials was determined by energy-dispersive x-ray and eluates were analyzed by inductively coupled plasma-mass spectrometry. Statistical differences were assessed by ANOVA and Tukey test (p < 0.05).

RESULTS

Under an acidic environment, both materials displayed similar ion release abilities, with the increased release of Si and Ca ions. Substantial changes in microstructure were observed for both materials after exposure to acidic pH. In addition, material exposure to an acidic environment showed a similar degree of cell adherence, and, surprisingly, MTA Repair HP exhibited higher cell viability rates at pH 5.2 than ProRoot MTA.

CONCLUSIONS

Exposure to an acidic environment promoted Si and Ca ion release from ProRoot MTA and MTA Repair HP. Moreover, we observed optimal biological properties of ProRoot MTA and MTA Repair HP in terms of cell viability, cell death, and cell attachment in both environments.

CLINICAL RELEVANCE

These results may suggest that MTA Repair HP and ProRoot exhibited optimal biological properties in terms of cell viability, cell death and cell attachment in acidic environment, being considered as materials for root-end filling and perforations.

Antimicrobial and anti-inflammatory drug-delivery systems at endodontic reparative material: Synthesis and characterization

OBJECTIVE

The aim of this study was to synthesize and characterize an experimental endodontic paste.

METHODS

An experimental endodontic paste (EX) was characterized by its particle size, zeta potential, drug content and morphology. The powder of EX is composed of amoxicillin microspheres, calcium tungstate and α-tricalcium phosphate, mixed with an indomethacin nanocapsules suspension. Ultracal^® (Ultradent), an iodoform-based paste (GP) and the EX were evaluated by its physical properties (flow, film thickness and radiopacity). The cytocompatibility was performed by MTT and SRB-colorimetric assays; the cell-migration was tested with scratch assay and cell-ability to remineralization with ALP and Alizarin Red S, with fibroblastic cell line. The antibacterial activity was assessed by the formation of inhibition zones and against planktonic bacteria.

RESULTS

The EX and UL flow achieved ISO6876 standard, and GP was lower than 17mm. All pastes achieved the film thickness required. Radiopacity was equivalent to 1.81±0.25mmAl for EX, which did not differ from GP group 1.39±0.33mmAl (p>0.05). The UL presented 3.04±0.33mmAl. The values for SRB showed better citocompatibility in comparison with MTT for all materials. The ALP activity and formation of mineralized nodules demonstrated the remineralization potential for UL and EX. Cell migration showed continuous wound closure until complete cell healing, however, the EX accelerated the process (p<0.05). The EX showed the greatest inhibition zone (p<0.05) and was the only group with antibacterial activity against planktonic bacteria.

SIGNIFICANCE

The synthesized endodontic paste demonstrated reliable physical and biological properties and could be a promising material for periapical tissue repair.

Evaluation of fracture resistance of roots-filled with various root canal sealers at different time periods

Purpose:

The reinforcement effect of 3 various root canal sealers (AH 26, MTA Plus sealer and BioRoot RCS) and gutta-percha at different time periods (1 week and 1 month) were evaluated in the present study.

Materials and methods:

Single-rooted, single-canalled, cracks-free 80 mandibular premolars were decoronated to a length of 13mm. Group PC (positive control, n=10): samples were left unprepared and unfilled. Seventy samples were prepared by using the ProTaper Rotary System up to F4. Group NC (negative control, n=10): samples were left unfilled. Remaining 60 samples were assigned into 3 groups; Group 1: AH 26 + F4 gutta-percha (GP); Group 2: MTA Plus sealer + F4 GP and Group 3: BioRoot RCS + F4 GP. Filled samples were divided into subgroups according to storage time: Samples in Groups 1A, 2A, and 3A were stored for 1 week; while Groups 1B, 2B and 3B were stored for 1 month at 100% humidity to allow the complete setting of the sealers (n=10, for each). A universal testing machine at a crosshead speed of 1.0 mm/min was used for fracture testing. For each specimen, the force at the time of fracture was recorded and the data were analyzed statistically.

Results:

The highest fracture resistance values were obtained in Group PC, while the lowest values were obtained in Group NC. Groups PC and NC were statistically different from each other and from other groups, regardless of time (p<0.05). Fracture resistance values of Group AH 26/GP were statistically different from MTA Plus sealer/GP (p<0.05) and were statistically similar with BioRoot RCS/GP , irrespective of time. Within group comparisons revealed that there were no statistically differences between samples filled with same sealer at different time periods.

Conclusion:

Root canal preparation caused decreased fracture resistance. All sealers increased the force values needed to fracture the filled samples compared to unfilled ones. Time factor had no effect on the fracture resistance values.

Evaluation of dentinal tubule penetration depth and push-out bond strength of AH 26, BioRoot RCS, and MTA Plus root canal sealers in presence or absence of smear layer

Background. This study compared the effect of smear layer on the penetration depth and push-out bond strength of various root canal sealers.

Methods. A total of 90 extracted human mandibular premolars were assigned into 2 groups: smear layer preserved and smear layer removed. Then the roots were further divided into 3 subgroups according to the sealer tested: AH 26, BioRoot RCS and MTA Plus. Obturation was performed with gutta-percha and the relevant sealer was mixed with 0.1% rhodamine B. Three 1-mm-thick slices were obtained from the mid-third area of each root. Two slices were selected for the push-out test and the remaining slice was used to calculate the dentinal tubule penetration depth and percentage.

Results. The retention of MTA Plus and BioRoot RCS was higher than that of AH 26 when the smear layer was preserved (P<0.05). BioRoot RCS showed the lowest penetration depth when the smear layer was removed (P<0.05).

Conclusion. Dentinal tubule penetration of root canal sealers had a limited effect on their adhesion to root canal wall.

Surface and vertical dimensional changes of mineral trioxide aggregate and biodentine in different environmental conditions

OBJECTIVES

Surface changes in biological environments are critical for the evaluation of physical and biological activity of biomaterials. Objective: This study investigated surface alterations of calcium silicate-based cements after exposure to different environments.

MATERIAL AND METHODS

Material and Methods: Forty-eight cylindrical cavities were prepared on root surfaces. The cavities were filled using ProRoot MTA or Biodentine and assigned to four subgroups (n=6): dry, wet, acidic, and blood. Surface topographies were evaluated using an optical profilometer for 28 days, and the roughness of the material surfaces was quantified. Vertical dimensional change was measured by determining the height difference between the material surface and the flat tooth surface. Data were compared with a two-way repeated measures ANOVA and Bonferroni tests.

RESULTS

Results: In dry condition, the surface roughness of MTA or Biodentine was constant up to 3 days (p>0.05) but decreased after 28 days (p<0.05). In dry condition, ProRoot MTA presented constant surface level through time, while Biodentine showed decreased surface level after 28 days. In wet condition, the roughness and the surface levels of both materials increased after 1 day (p<0.05). Neither the surface roughness nor the levels of the materials showed significant changes in acidic conditions (p>0.05). Both materials showed the highest roughness in blood conditions on the 1st day (p<0.05), while the surface roughness in blood decreased dramatically after 28 days. The roughness of Biodentine was higher in wet conditions up to 3 days compared with ProRoot MTA (p<0.05). Likewise, in blood condition, Biodentine showed higher roughness on the 28th day than ProRoot MTA (p<0.05).

CONCLUSIONS

Conclusions: Dry, wet, and blood conditions had a time-dependent effect on the surface roughness and vertical dimensional changes of the materials. However, acidic conditions did not affect the roughness and the surface level of the materials.

Tricalcium silicate-based cements: properties and modifications

Mineral trioxide aggregate (MTA) has been widely used for different reparative procedures in endodontics. The extensive use of this cement for pulp capping, apexifications, apical surgeries, and revascularization is related to its ability to induce tissue repair and to stimulate mineralization. Several research studies have tested modifications in the composition of MTA-based cements in order to enhance their clinical performance. Novel formulations have been introduced in the market with the aim of increasing flowability. Important properties such as appropriate radiopacity and setting time, color stability, alkaline pH, release of calcium ions, and biocompatibility have to be considered in these new formulations. The latest research studies on the physical, chemical, and biological properties of tricalcium silicate-based cements are discussed in this critical review.

Sealing ability of Biodentine versus ProRoot mineral trioxide aggregate as root-end filling materials

Aim

This study evaluated the sealing ability of ProRoot MTA and Biodentine as root-end filling materials.

Method

In total, twenty (N = 20) extracted human maxillary central incisor teeth were decontaminated, cleaned and decoronated. Instrumentation was performed according to the step back technique using #50 Flex-o-file. Then the canals were flared to #70 Flex-o-file. Obturation was performed with conventional gutta percha and a resinous sealer (AH26) using the lateral condensation technique. Resection of 3 mm of apical end of each root was achieved perpendicular to the long axis of the root. Root-end cavity was prepared in each sample ultrasonically then filled with tested materials (N = 10). Fluid filtration method was used to assess the sealing ability of each tested material at three different experimental periods; one day, one week and one month after setting. All data were tabulated and statistically analyzed with a level of significance set at P ≤ .05.

Results

At each specific time interval, the leakage mean values were not consistent among the tested materials. At one day interval, ProRoot MTA samples had a higher leakage mean value than Biodentine samples. However, this difference in leakage was not statistically significant (P > .05). At one week interval, both materials showed an increased degree of leakage mean value with no significant difference (P > .05). At one month interval, ProRoot MTA samples showed a decrease in leakage mean value, while the Biodentine samples showed a further increase in leakage mean value. This difference was statistically significant (P < .05).

Conclusion

Although the sealing ability of ProRoot MTA is superior to Biodentine, Biodentine could be considered as an acceptable alternative to ProRoot MTA in peri-radicular surgeries.

Fracture Resistance of Teeth with Simulated Perforating Internal Resorption Cavities Repaired with Different Calcium Silicate-based Cements and Backfilling Materials

INTRODUCTION

This study assessed the fracture resistance (FR) of teeth with simulated perforating internal resorption cavities repaired with different calcium silicate-based cements (CSCs) and backfilling materials.

METHODS

Ninety-six mandibular premolar teeth were used. Twelve of the teeth were assigned as negative control group. Remaining roots were instrumented with rotary files, and standardized internal resorption cavities were prepared on the middle half of roots with burs. Twelve of the samples were not further interfered and were assigned as a positive control group. The apical 4 mm of the remaining 72 root canals was obturated with single-cone technique and divided into 6 groups according to CSCs used for repairing of cavities and backfilling materials as follows: MTA + MTA, MTA + gutta-percha/sealer, Biodentine + Biodentine, Biodentine + gutta-percha/sealer, MTA Plus + MTA Plus, and MTA Plus + gutta-percha/sealer. Specimens were embedded in acrylic resin and then subjected to fracture testing. The forces when the fracture occurred were analyzed with analysis of variance and Bonferroni tests at P = .05.

RESULTS

No significant difference was found among CSCs irrespective of backfilling materials (P > .05). Groups MTA + gutta-percha/sealer, Biodentine + gutta-percha/sealer, and MTA Plus + gutta-percha/sealer showed significantly lower FR compared with groups MTA + MTA, Biodentine + Biodentine, and MTA Plus + MTA Plus, respectively (P < .05). The highest FR was observed in group Biodentine + Biodentine, and the lowest was in group MTA Plus + gutta-percha/sealer. FR of positive control group was statistically lower than groups completely filled with CSCs (P < .05), whereas FR of negative control group was statistically higher than the groups combined with gutta-percha and sealer (P < .05).

CONCLUSIONS

The backfilling with CSCs may be a preferable material rather than gutta-percha/sealer combination for the roots with perforated internal resorptions.

Different Setting Conditions Affect Surface Characteristics and Microhardness of Calcium Silicate-Based Sealers

OBJECTIVE

To investigate the effect of different setting conditions on surface microhardness and setting properties of calcium silicate-based sealers.

METHODS

Three sealers, EndoSequence Bioceramic (BC; Brasseler USA, Savannah, GA, USA), Endoseal MTA (ES; Maruchi, Wonju, Korea), and Well-Root ST (WR; Vericom, Chuncheon, Korea), were compared. Specimens were exposed to either butyric acid (pH 5.4) or phosphate-buffered saline (PBS [pH 7.4]) for 48 h and stored at 100% humidity for 12 days. The control specimens were stored at 100% humidity for 14 days. Surface microhardness was measured, topographic changes were observed, and phase analysis was performed using X-ray diffraction. Microhardness according to storage conditions was compared using one-way analysis of variance and Tukey's multiple comparison tests (P < .05).

RESULTS

The BC and ES sealers exhibited decreased microhardness when stored in acid or PBS compared with control (P < .05). In the WR group, acid exposure lowered microhardness of the specimens compared with control (P < .05). Scanning electron microscopy revealed different topographies in specimens from all tested sealers exposed to acid or PBS.

CONCLUSION

The surface microhardness of calcium silicate-based sealers was reduced by exposure to either acid or PBS. Acid solutions, however, had a more detrimental effect than PBS.

X-ray diffraction analysis of MTA mixed and placed with various techniques

OBJECTIVES

The aim of this study was to evaluate the effect of various mixing techniques as well as the effect of ultrasonic placement on hydration of mineral trioxide aggregate (MTA) using X-ray diffraction (XRD) analysis.

MATERIALS AND METHODS

One gram of ProRoot MTA and MTA Angelus powder was mixed with a 0.34-g of distilled water. Specimens were mixed either by mechanical mixing of capsules for 30 s at 4500 rpm or by manual mixing followed by application of a compaction pressure of 3.22 MPa for 1 min. The mixtures were transferred into the XRD sample holder with minimum pressure. Indirect ultrasonic activation was applied to half of the specimens. All specimens were incubated at 37 °C and 100% humidity for 4 days. Samples were analyzed by XRD. Phase identification was accomplished by use of search-match software utilizing International Centre for Diffraction Data (ICDD).

RESULTS

All specimens comprised tricalcium silicate, calcium carbonate, and bismuth oxide. A calcium hydroxide phase was formed in all ProRoot specimens whereas among MTA Angelus groups, it was found only in the sample mixed mechanically and placed by ultrasonication.

CONCLUSIONS

Mechanical mixing followed by ultrasonication did not confer a significant disadvantage in terms of hydration characteristics of MTA.

CLINICAL RELEVANCE

Clinicians vary in the way they mix and place MTA. These variations might affect their physical characteristics and clinical performance. For ProRoot MTA, the mixing and placement methods did not affect its rheological properties, whereas for MTA Angelus, mechanical mixing combined with ultrasonic placement enhanced the calcium hydroxide phase formation.

Success Rates of Pulpotomies in Primary Molars Using Calcium Silicate-Based Materials: A Randomized Control Trial

Objective

The aim of this study was to evaluate and compare, both clinically and radiographically, the effects of calcium silicate-based materials (i.e., ProRoot MTA [PR-MTA], MTA-Plus [MTA-P], and Biodentine [BD]) and ferric sulfate [FS] in pulpotomy of primary molars.

Materials and Methods

In this randomized clinical trial, 29 healthy 5- to 7-year-old children with at least four carious primary molars with no clinical or radiographic evidence of pulp degeneration were enrolled. The pulpotomy agents were assigned as follows: Group 1: BD; Group 2: MTA-P; Group 3: PR-MTA; and Group 4: FS. Clinical and radiographic evaluations were performed at 6, 12, and 24 months. Data were analyzed using chi-square tests.

Results

Total success rates at 24 months were 82.75%, 86.2%, 93.1%, and 75.86%, respectively. No statistically significant differences in total success rates were observed among the groups at 6-, 12-, and 24-month follow-ups. When the groups were compared according to follow-up times, the success rates in each group did not vary significantly among the 6–12-month, 6–24-month, or 12–24-month periods (p > 0.05).

Conclusion

Although the success rates of BD, MTA-P, MTA-PR, and FS did not differ significantly, calcium silicate-based materials appeared to be more appropriate than FS in clinical practice.

Long-term Success of Nonvital, Immature Permanent Incisors Treated With a Mineral Trioxide Aggregate Plug and Adhesive Restorations: A Case Series from a Private Endodontic Practice

This case series evaluated the long-term clinical outcome of nonvital immature teeth treated with mineral trioxide aggregate (MTA) as an apical barrier and an adhesive restoration with or without a fiber post. Eighty-three teeth in 72 patients were treated by the first author with an apical MTA plug and an adhesive restoration of composite resin and in 45 of the 83 teeth 1 or more fiber posts. All of the patients had been referred to the first author's private endodontic practice with at least 1 immature tooth with signs of pulpal necrosis and subsequent apical periodontitis that had been caused by a variety of traumatic dental injuries. Three teeth presented had dens invaginatus. Of 83 teeth, 69 teeth in 60 patients were available for follow-up after 5 to 15 years (recall rate = 83%). The mean follow-up time was 8.29 years. No teeth were lost because of a root fracture. Ninety-six percent (66/69) of the recalled teeth were characterized as healed. Based on periapical radiographs and clinical examination, 96% of teeth treated with the MTA barrier technique and adhesive restorations were characterized as "healed" and were in function after 5 to 15 years (mean = 8.29 years). These results indicate that this is a viable and predictable treatment approach for the long-term success of nonvital immature teeth.

Antimicrobial activity of ProRoot MTA in contact with blood

Dental materials based on Portland cement, which is used in the construction industry have gained popularity for clinical use due to their hydraulic properties, the interaction with tooth tissue and their antimicrobial properties. The antimicrobial properties are optimal in vitro. However in clinical use contact with blood may affect the antimicrobial properties. This study aims to assess whether antimicrobial properties of the Portland cement-based dental cements such as mineral trioxide aggregate (MTA) are also affected by contact with blood present in clinical situations. ProRoot MTA, a Portland cement-based dental cement was characterized following contact with water, or heparinized blood after 1 day and 7 days aging. The antimicrobial activity under the mentioned conditions was assessed using 3 antimicrobial tests: agar diffusion test, direct contact test and intratubular infection test. MTA in contact with blood was severely discoloured, exhibited an additional phosphorus peak in elemental analysis, no calcium hydroxide peaks and no areas of bacterial inhibition growth in the agar diffusion test were demonstrated. ProRoot MTA showed limited antimicrobial activity, in both the direct contact test and intratubular infection test. When aged in water ProRoot MTA showed higher antimicrobial activity than when aged in blood. Antimicrobial activity reduced significantly after 7 days. Further assessment is required to investigate behaviour in clinical situations.

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.

A comparative evaluation of sealing ability of four root end filling materials using fluid filtration method: An in vitro study

Aim of the Study

The aim of this study was to compare and evaluate the sealing ability of four root end filling materials mineral trioxide aggregate (MTA)-Plus, Biodentine, MTA (MTA Angelus) and glass ionomer cement (GIC) using fluid filtration method.

Materials and Methods

Forty-four extracted, human single-rooted teeth were collected. The crown of each tooth was decoronated 2 mm above the cementoenamel junction. Canals were negotiated, instrumented, obturated using lateral compaction method. The access cavities were sealed with Cavit. Root end resection and apical root end cavity preparations of 4 mm were made in each specimen. The selected roots were then randomly divided into four groups (n = 11) and restored as follows. Group 1 - GIC, Group 2 - MTA (MTA Angelus), Group 3 - Biodentine, and Group 4 - MTA Plus. The apical microleakage of each specimen was assessed using fluid filtration method at 72 h, 1 month and 3 months. Microleakage in each specimen was recorded in mm (millimeter) and converted to μl/min/cm H₂O.

Results

MTA Angelus showed least microleakage followed by Biodentine and MTA Plus. Least sealing ability was seen with GIC. There was statistically significant difference between all the materials at various time intervals.

Conclusion

MTA Angelus showed superior sealing ability as a retrograde filling material followed by Biodentine and MTA Plus.

Biocompatibility and bioactivity of calcium silicate-based endodontic sealers in human dental pulp cells

Mineral Trioxide Aggregate (MTA) is a calcium silicate-based material. New sealers have been developed based on calcium silicate as MTA Fillapex and MTA Plus.

Bioactivity of MTA Plus, Biodentine and an experimental calcium silicate-based cement on human osteoblast-like cells

AIM

To compare the bioactivity of Biodentine (BIO, Septodont), MTA Plus (MTA P, Avalon) and calcium silicate experimental cement (CSC) with resin (CSCR) associated with zirconium (CSCR ZrO₂ ) or niobium (CSCR Nb₂ O₅ ) oxide as radiopacifiers.

METHODOLOGY

According to the relevance of osteoblastic cell response for mineralized tissue repair, human osteoblastic cells (Saos-2) were exposed to test materials and assessed for viability (MTT), cell proliferation, gene expression of alkaline phosphatase (ALP) osteogenic marker by real-time PCR (RT-qPCR), ALP activity assay and alizarin red staining (ARS) to detect mineralization nodule deposition in osteogenic medium. Unexposed cells acted as the control group (C). Statistical analysis was carried out using ANOVA and the Bonferroni post-test (P < 0.05).

RESULTS

All tested cements showed dose-dependent responses in cell viability (MTT). Exposed cells revealed good viability (80-130% compared to the control group) in the highest dilutions of all types of cement. MTA P, BIO and CSCR ZrO₂ significantly increased the velocity of cell proliferation after three days of cell exposure in the wound-healing assay (P < 0.05), which corroborated MTT data. On day 3, the ALP transcript level increased, especially to CSCR Nb₂ O₅ (P < 0.05). All cements exhibited suitable ALP enzyme activity, highlighting the 7-day period of cell exposure. ARS, CSCR Nb₂ O₅ , revealed a significant potential to induce mineralization in vitro.

CONCLUSIONS

All materials had suitable biocompatibility and bioactivity. The MTA P, BIO and CSCR ZrO₂ groups had the highest viability rates and velocity of proliferation whilst the CSCR Nb₂ O₅ group produced more mineralized nodules.

Assessment of apical seal obtained after irrigation of root end cavity with MTAD followed by subsequent retrofilling with MTA and Biodentine: An in vitro study

Introduction:

The present study is designed to assess the apical seal obtained after root end cavity irrigation with MTAD and retrograde filling with mineral trioxide aggregate (MTA) and Biodentine.

Materials and Methods:

Sixty extracted maxillary central incisors were instrumented and obturated. Apical 3 mm of all the roots were resected and retrograde preparations of 3 mm were made in all the teeth using ultrasonic tips. Thirty root end preparations were irrigated with MTAD for 5 min (Group 1), while 30 were irrigated with saline for 5 min (Group 2). Each main group was subdivided into two subgroups containing 15 samples each. Samples under each subgroup were then filled either with MTA (1A and 2A) or Biodentine (1B and 2B). The amount of microleakage was assessed using a UV spectrophotometer.

Results:

Statistical analysis suggest a significant difference (P < 0.005) between group 1A and 2A and between the groups 1B and 2B (P < 0.1). There was a significant difference (P < 0.005) between group 1A and 1B and also between group 2A and 2B.

Conclusion:

Irrigation with MTAD significantly improved the apical seal of Biodentine, but it increased the microleakage in MTA-filled root end cavities. Also the apical seal obtained with Biodentine was superior to that obtained with MTA.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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