Calcium silicate aluminate aggregate (CSAA) and its carrier for endodontic applications

Abstract

Calcium Silicate–Aluminate Aggregate (CSAA) compositions and associated preparation and delivery systems for endodontic and dental repair procedures are disclosed. In certain embodiments, the composition comprises a calcium silicate-based matrix derived from Portland cement, a calcium aluminate phase, and a radiopacifying agent. The composition may be mechanically milled to produce a multimodal particle-size distribution and mixed with an aqueous liquid to form a hydraulic cement paste suitable for root-end filling, perforation repair, pulp capping, apexification, regenerative endodontic procedures, and root canal sealing. In further embodiments, a closed dual-syringe system stores powder and liquid components in separate chambers and permits reciprocal transfer and mixing to form a substantially homogeneous paste for direct delivery to a dental treatment site. The disclosed compositions and systems may provide reduced setting time, controlled handling, and radiographic detectability.

Description

CALCIUM SILICATE ALUMINATE AGGREGATE (CSAA) AND ITS CARRIER FOR ENDODONTIC APPLICATIONSCROSS-REFERENCE TO RELATED APPLICATIONSThe present application claims the benefit of and priority to U.S. Patent Application Serial No.19 / 636,644, filed on April 1, 2026, and to U.S. Provisional Patent Application No. 63 / 777,128, filed on March 25, 2025, each of which is expressly incorporated herein in its entirety by reference thereto.BACKGROUND OF THE INVENTION1. Field of the Invention

[0001] The subject matter relates generally to dental materials and, more particularly, to bioactive hydraulic cement used in endodontic procedures for repair, sealing, and / or replacement of tooth structure in clinical environments where moisture may be present.

[0002] Such materials are used in applications that can include root-end filling, perforation repair, apexification, vital pulp therapy (e.g., pulp capping and pulpotomy), regenerative endodontic procedures and root canal obturation, where a placed material is expected to provide sealing performance and favorable tissue response over time.2. Description of Prior Art and Related Information

[0003] A range of endodontic repair materials has been proposed to seal communications between the root canal system and external tooth surfaces and to support periapical healing. Historically, a variety of materials have been used for sealing or filling in endodontic contexts, including cements and restorative compositions with differing handling, sealing, and biological profiles, reflecting the broad effort to identify materials suitable for various clinical conditions.

[0004] Mineral trioxide aggregate (MTA) and related calcium silicate-based hydraulic cements have become widely used materials in endodontics and pediatric dentistry, in part because these materials can set via hydration and are used in procedures where moisture control can be difficult. MTA-type materials have been described as based largely on calcium silicate phases, with radiopacifier added to permit radiographic visualization, and they have been evaluated across laboratory, animal, and clinical studies for a range of endodontic indications.

[0005] Conventional MTA formulations have been described as containing calcium silicates and additional phases such as calcium aluminates and calcium sulfate and have commonly incorporatedbismuth oxide as a radiopacifier. Upon hydration, such materials can form calcium silicate hydrate phases and calcium hydroxide, which can contribute to an alkaline environment that may be associated with antibacterial effects and bioactivity in some usage contexts.

[0006] In view of clinical shortcomings of the original MTA and commercial demand, additional calcium silicate-based cements and “MTA-like” products have been introduced, including products marketed as “bioceramic” materials as well as alternative restorative cements with similar elemental or oxide profiles. Variations across products may include differences in powder composition, radiopacifier selection, particle size distribution, additives intended to modify rheology, and delivery format (e.g„ powder-liquid mixes versus premixed pastes), with these variations influencing test outcomes and clinical handling characteristics.

[0007] Testing and comparison of MTA and related hydraulic cements have often referenced international standards and methodologies for evaluating physical properties and biocompatibility, including standards addressing flow, working time, setting time, solubility, radiopacity, mechanical strength, and biological evaluation. Reported results can depend on curing methodology and test environment, and some discussions emphasize that hydration-dependent materials may exhibit different performance when tested under conditions that do not reflect physiological temperature, moisture, and ionic composition.

[0008] Clinical use of hydraulic endodontic repair materials also implicates placement techniques and delivery devices. In practice, materials may be placed into confined anatomical sites or surgical preparations using earners, syringes, or other placement tools, and placement methods can affect extrusion risk, contamination, adaptation, and consistency of the placed mass. A variety of delivery approaches have been used for MTA placement, reflecting the practical need to deliver a moldable cement into small cavities with positional control.

[0009] Notwithstanding widespread use and favorable attributes reported for MTA and related calcium silicate-based cements, multiple limitations have been noted in the field. Examples include prolonged and sometimes unpredictable setting times, variability introduced by powderliquid ratios and manual mixing, handling challenges in clinical placement, and issues related to radiopacity and esthetics depending on the radiopacifier chemistry. Cost and workflow considerations, as well as concerns raised regarding trace elements or long-term behavior for some formulations, have also been discussed.

[0010] Setting time is frequently identified as a practical constraint for hydraulic endodontic repair materials. Reports describe that certain MTA-type materials can have relatively long setting periods, and that setting outcomes may be influenced by curing methodology, environmental moisture, andexposure to clinical contaminants such as blood. Additives and alternative formulations have been explored to alter setting kinetics, but such modifications can also be associated with tradeoffs in other material properties depending on composition and testing conditions.

[0011] Tooth discoloration and radiopacifier-related interactions have also been noted as a concern in some clinical contexts, particularly where esthetics are important. Formulations using bismuth oxide have been associated with discoloration potential in some scenarios, including interactions with endodontic irrigants dentin components and blood, and alternative radiopacifiers have been explored in an effort to mitigate such effects while maintaining radiographic visibility.

[0012] Accordingly, there remains an ongoing technical and clinical interest in endodontic repair materials that can provide sealing performance and favorable biological response comparable to established calcium silicate-based cements, while also improving practical aspects such as setting time, handling consistency, delivery, radiographic visibility, and esthetic outcomes, recognizing that performance may depend on clinical environment and testing methodology.

[0013] Despite numerous calcium silicate-based materials currently available, there remains a need for hydraulic dental cements that combine rapid setting kinetics, improved sealing ability, reduced discoloration potential, and predictable handling characteristics using a standardized delivery system while maintaining the biocompatibility and bioactivity associated with traditional mineral trioxide aggregate materials.SUMMARY OF THE INVENTION

[0014] The present disclosure relates to a bioactive hydraulic dental cement composition and associated preparation and delivery systems for use in endodontic and dental repair procedures. In certain embodiments, the composition comprises a calcium silicate-based matrix derived from Portland cement together with a calcium aluminate phase and a radiopacifying component. The composition is configured to hydrate in the presence of moisture to form a hardened cement suitable for root-end filling, perforation repair, pulp capping, apexification, regenerative endodontic procedures, and root canal obturation. In some embodiments, the cement powder is subjected to mechanical size reduction, such as ball milling, to produce heterogeneous particle distribution including nano-scale particles that increase surface area and enhance hydration kinetics. The resulting cement composition may exhibit a working time of approximately 4-6 minutes and a final setting time of approximately 8-10 minutes while maintaining alkaline pH, radiopacity, dimensional stability, and bioactivity. In certain implementations, the powder component may be mixed with an aqueous liquid to form a hydraulic cement paste having application- specific viscosity. For example, a powderdiquidratio of approximately 2:3 may be used when the material is employed as an endodontic sealer, while a powderliquid ratio of approximately 1:3 may be used for repair procedures including root-end filling, perforation repair, pulp regeneration and pulp capping. In certain embodiments, biological performance of the composition may be evaluated through in vitro and in vivo testing. In vitro cytotoxicity studies using cultured human gingival fibroblast cells demonstrate cell viability comparable to control groups with no detectable cytotoxic effects. In vivo evaluations in animal models demonstrate absence of inflammatory response and formation of periodontal ligament tissue adjacent to treated root surfaces, indicating favorable tissue integration following placement of the cement. Leakage evaluation using dye penetration testing further demonstrates effective sealing performance, with no detectable dye infiltration at the material-dentin interface under the tested conditions. In further embodiments, preparation and delivery of the cement may be performed using a closed mixing system comprising a first syringe containing a liquid component and a second syringe containing a powder component, the syringes being connectable through a Luer-lock interface. Reciprocal transfer of the components between the syringes through repeated in-and-out movement may produce a homogeneous cement paste within the closed system, which may then be delivered directly from the syringe to the treatment site and reduce chances for contamination. In certain embodiments, the invention provides a Calcium Silicate- Aluminate Aggregate (CSAA) cement composition characterized by accelerated hydration kinetics, reduced setting time relative to conventional MTA materials, improved sealing performance in endodontic applications and reduced chances for tooth discoloration.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS AND BEST MODE OF INVENTION

[0015] The following description sets forth representative embodiments of a CSAA composition and associated preparation and delivery systems suitable for endodontic and dental repair procedures. The described compositions are hydraulic dental cements capable of setting in the presence of moisture and may be used in procedures including root-end filling, perforation repair, apexification, pulp capping, pulpotomy, regenerative endodontic procedures, and root canal obturation.

[0016] In certain embodiments, the CSAA composition comprises a calcium silicate-based matrix derived from Portland cement. The Portland cement component may include calcium oxide (CaO), silicon dioxide (SiC>2), aluminum oxide (AI2O3), and iron oxide (Fe2O3), which together form hydraulic phases capable of reacting with water to produce calcium silicate hydrate and related hydration products. In some embodiments, the formulation further includes a calcium aluminate phaseconfigured to accelerate hydration reactions and reduce the setting time of the cement. The composition may include a radiopacifying component selected from barium titanate, titanium oxide, tantalum oxide, or mixtures thereof, which allows the cement to be visualized using conventional dental radiographic imaging techniques. The radiopacifier may be incorporated in an amount sufficient to provide radiopacity greater than that of dentin and comparable to or exceeding the minimum requirements specified in international dental material standards. For sealer applications requiring increased radiographic visibility, the radiopacifying component may comprise a mixed radiopacifier system including tantalum (V) oxide (Ta2C>5) and barium titanate (BaTiOq. wherein the Ta2Os and BaTiCF are present at a weight ratio of about 1:9 to about 1:1, preferably about 30:70 Ta2Os:BaTiO3, and wherein the mixed radiopacifier system is present in an amount effective to provide radiopacity greater than 3 mm Al, and in some embodiments at least about 4 mm Al, when tested according to ISO 6876 or an equivalent radiopacity test method. Representative elemental oxide composition data for the CSAA powder and a comparative mineral trioxide aggregate material are summarized in Table 1.

[0017] In certain embodiments, the resulting powder may exhibit a median particle size from about 0.5 pm to about 5 pm. A powder mixture comprising a calcium silicate-based matrix, a calcium aluminate phase, and a radiopacifying component may be mechanically milled, including by planetary ball milling, for a time sufficient to produce a multimodal particle size distribution including submicron particles and nano-scale particles. In certain embodiments, the milling time is from about 1 hour to about 4 hours. In some embodiments, the resulting powder comprises particles having diameters of about 0.2 pm to about 1.0 pm, particles having diameters of about 3 pm to about 8 pm, and a maximum observed particle size of about 10 pm. In certain embodiments, the reduced particle size and increased surface area improve hydration kinetics, handling properties, injectability, and setting characteristics upon mixing with an aqueous liquid. Representative SEM images are shown in FIG. 1, and quantitative particle size data are summarized in Table 2.

[0018] The resulting CSAA powder may exhibit a heterogeneous particle population including nano-and submicron particles together with larger irregular grains. Such particle distribution may increase the available surface area for hydration reactions and may influence handling properties and hydration kinetics.

[0019] For clinical preparation, the CSAA powder component may be combined with an aqueous liquid to form a moldable hydraulic cement paste suitable for placement into a dental treatment site. In certain embodiments, the liquid component comprises distilled water, sterile water, saline, or another aqueous solution capable of initiating hydration of the cement. The powder and liquidcomponents may be mixed immediately prior to use to produce a workable paste having a viscosity appropriate for the intended endodontic procedure. In some embodiments, the powderdiquid ratio may range from approximately 1:3 to 2:3 by weight, depending on the desired consistency and clinical application. Lower powder content mixtures may produce a more flowable paste suitable for use as an endodontic sealer or for applications requiring enhanced flow and penetration into dentinal structures, while higher powder content mixtures may produce a thicker paste appropriate for procedures such as root-end filling, perforation repair, pulp capping, pulp regeneration, or apexification. Upon mixing with the aqueous liquid, the hydraulic cement undergoes hydration reactions that progressively convert the paste into a hardened bioactive cement capable of adhering to surrounding dentin and providing a durable seal.

[0020] In some embodiments, mixing of the powder and liquid components may be performed using a closed mixing system. One example includes a new dual-syringe delivery device comprising a first syringe containing the liquid component and a second syringe containing the powder component.

[0021] Reciprocal movement of the syringe plungers may allow repeated transfer of the powder and liquid between the syringes, producing a substantially homogeneous cement mixture within a closed system. The mixed cement may then be delivered directly to a treatment site through different needle sizes without the use of external mixing elements such as mixing pads, spatulas or carriers.

[0022] The syringe delivery configuration may allow controlled mixing of the powder and liquid components while reducing exposure of the cement mixture to external contaminants. The enclosed configuration may also reduce material loss associated with manual mixing techniques (Figure 7).

[0023] The sealing ability of the CSAA cement may be evaluated using a dye penetration method to assess potential microleakage at the material-tooth interface. In one representative experiment, rootend cavities filled with the CSAA cement were immersed in a methylene blue dye solution for 24 hours, after which the specimens were longitudinally sectioned and examined under optical microscopy. Microscopic evaluation of the specimens at approximately 4x and lOx magnification revealed no detectable dye penetration in any of the tested samples (n = 10) under the tested experimental conditions. All specimens demonstrated complete resistance to dye infiltration at the interface between the CSAA material and the surrounding dentin structure. Representative microscopic images illustrating the absence of dye penetration are shown in Figure 2. The absence of dye penetration suggests the formation of a continuous and well-adapted interface between the cement and dentin under the tested experimental conditions, indicating effective marginal sealing under the tested conditions. This sealing performance may be associated with the particle size distribution and hydration behavior of the CSAA composition, which may promote dense packing of particles andinterfacial adaptation during the setting reaction. The presence of fine particles may enhance marginal integrity by filling interstitial spaces within the prepared cavity, while the relatively rapid setting characteristics may reduce early washout and improve sealing performance. Although dye penetration represents a laboratory model, the consistent absence of leakage in all specimens supports the ability of the CSAA cement to provide an effective apical seal against bacterial penetration which makes this material suitable for endodontic repair and root-end filling applications.

[0024] Working time and setting time of the CSAA cement may be determined by using indentation testing methods under conditions consistent with ISO 6876. In one embodiment, the working time may be approximately 4-6 minutes and the final setting time may be approximately 8-10 minutes. Comparative results are summarized in Table 3.

[0025] Hydration of the cement composition may generate alkaline reaction products. pH measurements performed following hydration indicate alkaline conditions with values approximately 12 or greater after 24 hours of immersion.

[0026] Flow properties of the cement mixture may be evaluated according to ISO 6876 testing methodology. Representative flow measurements for the CSAA composition are summarized in Table 4.

[0027] Solubility and dimensional stability may be evaluated by immersion testing following standardized procedures (ISO 6876:2012). Representative values for solubility and dimensional change are summarized in Table 5.

[0028] Radiopacity of the CSAA cement may be evaluated using radiographic imaging techniques in combination with an aluminum step wedge calibration in accordance with methodologies commonly used for dental materials testing. In one representative evaluation, cement specimens were radiographically imaged adjacent to a standardized aluminum step wedge, and the grayscale intensity values obtained from the radiographs were converted to equivalent aluminum thickness values. The measured radiopacity of the CSAA cement demonstrated a mean equivalent aluminum thickness of approximately 3.29 mm Al, which exceeds the minimum radiopacity requirement specified by ISO 6876 for endodontic sealing materials (> 3 mm Al). Comparative measurements obtained for ProRoot MTA demonstrated higher radiopacity values due to the presence of bismuth oxide as a radiopacifier; however, the radiopacity of the CSAA composition remained well above the threshold required for radiographic detectability in clinical applications. These findings confirm that the CSAA cement provides sufficient radiographic contrast to permit reliable visualization of the material following placement in endodontic procedures. Quantitative radiopacity data and statistical analysis aresummarized in Table 6, and a representative radiographic configuration used for this evaluation is illustrated in Figure 3.

[0029] Bioactivity evaluation may be performed by immersion of cement specimens in simulated body fluid. Surface mineralization behavior observed after immersion periods may be assessed using microscopy techniques.

[0030] The cytotoxicity results demonstrate that the CSAA cement compositions maintain cell viability levels comparable to untreated control cells and to commercially available MTA materials. In particular, the CSAA formulations exhibited cell viability values of approximately 94-99%, indicating no cytotoxic effect on human gingival fibroblast cells under the tested conditions. These findings confirm that the CSAA compositions possess biocompatibility suitable for endodontic and dental repair applications, while maintaining the physicochemical and handling advantages described herein. Cell viability values are expressed as mean ± standard deviation (n = 3). Statistical analysis was performed using one-way analysis of variance (ANOVA) followed by post-hoc comparison testing. No statistically significant difference in cell viability was observed between CSAA samples and the untreated control (p > 0.05). The DMSO positive control demonstrated a statistically significant reduction in cell viability compared with all other groups (p < 0.001). Representative cell viability data obtained from such testing are summarized in Table 7.

[0031] In certain embodiments, the powderiliquid ratio may be adjusted depending on the intended clinical application. For example, when the hydraulic cement composition is used as an endodontic sealer, the powder component comprising the CSAA may be mixed with an aqueous liquid at a powderdiquid ratio of approximately 2:3 to produce a flowable hydraulic cement paste capable of penetrating dentinal tubules and adapting to root canal walls. In contrast, when the composition is used as a repair material, including applications such as root-end filling, perforation repair, pulp capping, or regenerative endodontic procedures, the powder component may be mixed with an aqueous liquid at a powderiliquid ratio of approximately 1:3 to produce a higher-viscosity cement paste suitable for placement and retention at the treatment site.

[0032] The in-vivo histological results demonstrate that the CSAA cement composition exhibits excellent biological compatibility and regenerative potential when used as a root-end filling material in endodontic microsurgery procedures in dogs. Representative postoperative animal radiographic images illustrating the surgical sites and periapical healing after four months are shown in Figure 5. Histological evaluation of the treated specimens further demonstrated favorable tissue response following placement of the CSAA cement. Figure 6 illustrates representative histological micrographs of the treated root-end sites during microsurgery in dogs, showing regeneration of periapical tissuesincluding formation of periodontal ligament-like structures and newly formed bone adjacent to the resected root surface. In the evaluated specimens, all CSAA-treated samples demonstrated complete periapical soft- and hard-tissue regeneration with no observable inflammatory response, whereas a smaller proportion of the comparative samples exhibited complete healing (8 out 12). Statistical comparison of the paired treatment sites indicated a significant difference in complete histological outcomes between the CSAA and control groups (p < 0.05). These findings indicate that the CSAA cement composition possesses excellent in-vivo biocompatibility and promotes favorable periapical tissue regeneration, supporting its suitability for clinical applications including root-end filling, perforation repair, apexification, pulp capping, and regenerative endodontic procedures.

[0033] Although specific embodiments have been described for purposes of illustration, variations in component concentrations, particle size distributions, accelerator content, radiopacifier type, mixing systems, and delivery configurations may be used while remaining within the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 illustrates representative SEM images of the CSAA powder at different magnifications, including (a) approximately 35,000x (scale bar = 5 pm) and (b) approximately 70,000x (scale bar = 1 pm), showing heterogeneous particle size distribution with predominantly angular and irregular particles.

[0035] Figure 2 illustrates representative microscopic images obtained from the dye penetration leakage evaluation of root-end cavities filled with CSAA cement. The images demonstrate the interface between the cement and surrounding dentin following immersion in a methylene blue dye solution. Microscopic examination at approximately 4x and lOx magnification shows no observable dye penetration along the material-dentin interface, indicating effective sealing and resistance to microleakage under the experimental conditions.

[0036] Figure 3 illustrates a representative radiographic image showing the radiopacity evaluation setup, including a CSAA specimen positioned adjacent to an aluminum step wedge for determination of equivalent aluminum thickness.

[0037] Figure 4 illustrates representative results of cytotoxicity evaluation, including exposure of material specimens to cultured human gingival fibroblast cells and subsequent viability assessment.

[0038] Figure 5 illustrates representative postoperative imaging obtained from the in-vivo animal study evaluating the biological response following endodontic microsurgery procedures, (a) Postoperative periapical radiographs obtained immediately following the surgical procedures andplacement of the root-end filling materials, (b) Follow-up periapical radiographs obtained after a healing period of approximately four months demonstrating periapical tissue healing, (c) Representative cone-beam computed tomography (CBCT) images obtained at the conclusion of the study following completion of the in-vivo study and fixation of the mandibles in approximately 10% buffered formalin, illustrating the three-dimensional evaluation of the periapical region and surrounding bone structures.

[0039] Figure 6 illustrates representative histological micrographs of periapical tissues following endodontic microsurgery and placement of root-end filling materials in the in-vivo animal study, (a) Low-magnification micrograph (4x) of a root-end site filled with the CSAA cement composition demonstrating regenerated periapical tissues and newly formed bone adjacent to the resected root surface, (b) Higher-magnification micrograph (lOx) of the CSAA-treated site illustrating normal tissue architecture and absence of inflammatory cell infiltration, (c) Low-magnification micrograph (4x) of a comparative site treated with MTA. (d) Higher-magnification micrograph (lOx) of the MTA-treated site illustrating the surrounding periapical tissue response.

[0040] Figure 7 illustrates a side view of Syringe B, the male syringe, configured for use in the dualsyringe mixing and delivery system of the present invention. The syringe comprises a male Luer-lock hub positioned at the distal end of the syringe and configured to connect to a complementary female Luer-lock connector of a second syringe to permit fluid communication during mixing. The syringe further includes a rubber stopper disposed within the syringe chamber and movable along the interior of the barrel. A plunger is connected to the rubber stopper and is configured to be reciprocally actuated by a user to displace material within the barrel, thereby enabling transfer and mixing of powder and liquid components when coupled to the corresponding syringe. FIG. 7A illustrates a top view of the male Luer-lock hub showing the threaded locking interface configured to engage a corresponding female Luer-lock connector.

[0041] Table 1 presents X-ray fluorescence (XRF) elemental oxide composition data for CSAA and a comparative material, including relative weight percentages of CaO, ALCh, SiCL, BaO, TiCF, and additional minor oxides.

[0042] Table 2 summarizes quantitative particle size distribution parameters of CSAA compared with a reference material, including submicron fraction, larger grain range, and maximum observed particle size.

[0043] Table 3 provides statistical comparison of working time and final setting time between CSAA and a comparative material, including mean values, standard deviations, and p-values.

[0044] Table 4 presents flow measurement results for CSAA and a comparative material determined in accordance with ISO 6876:2012, including mean diameter, standard deviation, and confidence interval values.

[0045] Table 5 summarizes solubility and dimensional change data following immersion testing, including mass loss and dimensional variation for CSAA and a comparative material.

[0046] Table 6 presents radiopacity and extended immersion data, including mean grayscale-derived aluminum equivalence values, standard deviations, and statistical analysis results for CSAA and comparative material.

[0047] Table 7 summarizes cytotoxicity test results, including average cell viability percentages, standard deviations, and qualitative toxicity conclusions for tested groups. Cytotoxicity Evaluation of Cement Samples Using Human Gingival Fibroblast (HGF) Cells, MTS Assay, 24-hour exposure.TABLES

[0048] Table 1 presents X-ray fluorescence (XRF) elemental oxide composition data for CSAA and a comparative material, including relative weight percentages of CaO, AECh, SiCE. BaO, TiCE. and additional minor oxides.Element CSAA (wt%) ProRoot MTA (wt%)CaO 52.211 63.4ALOa 13.613 1.62BaO 12.814 0BBO3 0 14.9Si0211.191 16.1Ti()25.672 0SO32.348 2.41MgO 0.707 0.280IGO 0.512 0.102Na2O 0.451 0Fe2O30.193 0.287SrO 0.166 0.104P2O5 0.073 0.154Nb2Os 0.049 0MnO 0 0.022Cl 0 0.017NiO 0 0.011

[0049] Table 2 summarizes quantitative particle size distribution parameters of CSAA compared with a reference material, including submicron fraction, larger grain range, and maximum observed particle size.Parameter CSAA ProRoot MTA p-vahieSubmicron fraction (pm) 0.2-1.0 <1.0 < 0.05Larger grain range (pm) 3-8 10-30 < 0.05Maximum observed size (pm) -10 30-50 < 0.05

[0050] Table 3 provides statistical comparison of working time and final setting time between CSAA and a comparative material, including mean values, standard deviations, and p-values.Parameter Material n Mean ± SD (min) p-valueWorking Time CSAA 5 5.0 ± 0.8 < 0.001 Working Time ProRoot MTA 5 12.5 ± 1.2 < 0.001 Final Setting Time CSAA 5 9.0 ± 0.8 < 0.001Final Setting Time ProRoot MTA 5 165 ± 15 < 0.001

[0051] Table 4 presents flow measurement results for CSAA and a comparative material determined in accordance with ISO 6876:2012, including mean diameter, standard deviation, and confidence interval values.Material n Mean (mm) SD (mm) 95% CI (mm)CSAA 10 10.36 ±1.52 9.27 - 11.45ProRoot MTA 10 10.10 ±1.40 9.10 - 11.10

[0052] Table 5 summarizes solubility and dimensional change data following immersion testing, including mass loss and dimensional variation for CSAA and comparative material.Material Category Group Solubility (% wt loss ± SD) Dimensional Change (% ± SD) Root-End CSAA 2.10 ± 0.25% 0.22 ± 0.06%Root-End (Control) ProRoot MTA 2.35 ± 0.31% 0.11 ± 0.04%

[0053] Table 6 presents radiopacity and extended immersion data, including mean grayscale-derived aluminum equivalence values, standard deviations, and statistical analysis results for CSAA and comparative material.Group n Mean Std. Deviation Median Minimum Maximum P value CSAA 10 3.2860 0.35960 3.1550 2.94 3.85 <0.001*bProRoot MTA 10 5.1268 0.37995 4.9880 4.81 5.83 <0.001*bTotal 20 4.2064 1.01062 4.3290 2.94 5.83bMann-Whitney U test, *p < 0.05 statistically significant

[0054] Table 7 summarizes cytotoxicity test results, including average cell viability percentages, standard deviations, and qualitative toxicity conclusions for tested groups. Cytotoxicity Evaluation of Cement Samples Using Human Gingival Fibroblast (HGF) Cells (MTS Assay, 24 h Exposure)Sample Group Mean Cell Viability (%) Standard Deviation (SD) Untreated Control (NT) 100.00 ±3.35DMSO (30%) Positive Control 17.68 ±0.18Whatman Disc 90.15 ±8.58 Sample 1 - CSAA Cement 99.14 ±7.99Sample 2 - ProRoot MTA 96.33 ±6.39

Claims

CLAIMS1. A bioactive hydraulic dental cement composition for endodontic repair, comprising:a calcium silicate-based matrix derived from Portland cement;a calcium aluminate phase present in an amount effective to accelerate hydration of the composition; anda radiopacifying agent,wherein the composition is configured to react with an aqueous liquid to form a hardened bioactive cement for use in a dental repair procedure.

2. The composition of claim 1, wherein the dental repair procedure comprises at least one of rootend filling, perforation repair, pulp capping, apexification, or root canal sealing.

3. The composition of claim 1, wherein the Portland cement comprises calcium oxide, silicon dioxide, aluminum oxide, and iron oxide.

4. The composition of claim 1, wherein the composition comprises approximately:40-70 wt% calcium oxide;5-25 wt% silicon dioxide;5-25 wt% aluminum oxide; and3-15 wt% radiopacifying agent.

5. The composition of claim 1, wherein the radiopacifying agent comprises a metal oxide, a metal titanate, or a combination thereof.

6. The composition of claim 5, wherein the radiopacifying agent comprises barium titanate, titanium oxide, tantalum oxide, or a combination thereof.

7. The composition of claim 1, wherein the composition is substantially free of bismuth oxide.

8. The composition of claim 1, wherein at least a portion of particles of the composition have a particle size of less than about 1 pm.

9. A method of preparing a hydraulic dental cement composition, comprising:providing a powder mixture comprising Portland cement, calcium aluminate, and a radiopacifying agent; andmechanically milling the powder mixture for about 1-4 hours to produce a powder having a multimodal particle size distribution including nanoscale particles,wherein the milled powder is subsequently mixable with an aqueous liquid to form a hydraulic cement paste.

10. The method of claim 9, wherein the mechanical milling is performed using a planetary ball mill.

11. The method of claim 9, further comprising mixing the milled powder with the aqueous liquid at a powder-to-liquid ratio of about 1:3 when the hydraulic cement paste is used as a repair material.

12. The method of claim 9, further comprising mixing the milled powder with the aqueous liquid at a powder-to-liquid ratio of about 2:3 when the hydraulic cement paste is used as an endodontic sealer.

13. A closed mixing and delivery system for preparing a hydraulic dental cement composition, comprising:a first chamber containing an aqueous liquid component;a second chamber containing a cement powder component comprising a calcium silicate-based hydraulic cement; anda connector configured to place the first chamber and the second chamber in fluid communication, wherein the system is configured to permit reciprocal transfer of the aqueous liquid component and the cement powder component between the first chamber and the second chamber to produce a substantially homogeneous hydraulic cement paste for delivery into a dental treatment site.

14. The system of claim 13, wherein the first chamber and the second chamber comprise syringes connected by a Luer-lock interface.

15. The system of claim 14, wherein one of the syringes comprises a male Luer hub having an external Luer-lock thread.

16. The system of claim 14, wherein the syringes comprise rubber stoppers configured to reciprocate within syringe barrels during mixing.

17. The system of claim 13, wherein the closed mixing and delivery system is configured to reduce loss of cement powder during mixing.

18. A kit for preparing a hydraulic dental cement, comprising:a powder component comprising the composition of claim 1;a liquid component configured to hydrate the powder component; anda mixing and delivery device comprising two syringes connectable by a Luer-lock interface for mixing the powder component and the liquid component prior to delivery.

19. A method of performing an endodontic repair procedure, comprising:mixing an aqueous liquid with the composition of claim 1 to form a hydraulic cement paste; and placing the hydraulic cement paste into a dental treatment site of a tooth, wherein the dental treatment site comprises at least one of a root-end cavity, a perforation site, a pulp exposure site, or a root canal system,wherein the hydraulic cement paste hydrates and hardens to form a bioactive sealing material for endodontic repair.

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