Effect of MTA particle size on periapical healing

A Review of the research methods and progress of biocompatibility evaluation of root canal sealers

The function of root canal sealer was to achieve an appropriate three-dimensional filling effect by filling the root canal and some irregular lumen, thereby inhibiting the residual bacteria. There were many types of sealers, but research to find the most suitable ones was still ongoing. In recent years, researchers had continuously improved the performance of sealers by developing new sealers or adding active ingredients to the sealers. However, most sealers exhibit varying degrees of cytotoxicity and tissue responses, which affect clinical therapy efficacy. This review describes different technical approaches, and recent research progress in the biocompatibility evaluation of root canal sealers and provides brief insights into this field by summarising the performance studies of different root canal sealers.

Physicochemical properties and biocompatibility of various bioceramic root canal sealers: in vitro study

INTRODUCTION

The aim of this study was to compare the physicochemical properties and biocompatibility of various calcium silicate-based bioceramic sealers (CSBSs).

METHODS

Four recently developed CSBSs, including AH Plus Bioceramic Sealer (AHB), EndoSequence BC Sealer (ESB), TotalFill BC Sealer (TTB), and Bio-C Sealer (BIC), were compared with the epoxy resin-based sealer AH Plus (AHP). Their physical properties, including flow, setting time, radiopacity, dimensional stability, and pH, were evaluated according to International Organization for Standardization (ISO) 6876. Their cytotoxicity in human periodontal ligament fibroblast (hPDLF) was assessed through the MTT assay and compared. Additionally, cell attachment to the sealer surface was analysed using green fluorescent protein and confocal laser scanning microscopy (CLSM) to evaluate cell viability. Data were analysed using one-way analysis of variance to determine the difference between groups for categorical variables, followed by Tukey's post-hoc test at the significance level of 95%.

RESULTS

The flow, setting time, and radiopacity of all tested CSBSs satisfied the ISO 6876/2012 standards. Further, these CSBS showed shrinkage after immersion in distilled water for 30 days and complied with the ISO 6876/2001 requirements. The pH of AHB, ESB, TTB, and BIC was greater than 11 whereas AHP had a pH of 6.69 after 4 weeks. CSBS showed excellent biocompatibility compared with that of AHP (P < .05). CLSM showed that alive hPDLFs were attached well to all the tested CSBS but not to AHP.

CONCLUSIONS

CSBS have similar physical characteristics within the ISO standards and higher biocompatibility than epoxy resin-based sealers.

Hydration reaction analysis of calcium-silicate-based materials using Scanning Electron Microscopy and X-ray Diffraction method

Background/Aim: The components of calcium silicate-based materials can be identified through X-Ray Diffraction Analysis. This study aimed to determine the hydration reactions and particle size of MTA Angelus, Biodentine, and NeoMTA Plus as calcium-silicate-based materials. Material and Methods: The powder and set cement samples using divergence and scatter slits of 1 ○ and a receiver slit of 0.10 mm. The scanning range was set at 5 ○ to 70 ○ , and ongoing scans for the theta-2theta range was performed with a scan speed of 2 ○ /minute (-1). The patterns obtained were analyzed using search-match software. The three most substantial peaks were used to identify hydration reactions and major crystalline structures. Also, Scanning Electron Microscope (SEM) analysis was performed and the particle size of set materials were determined using an image analysis software. Results: According to X-Ray Diffraction Analysis, the main components were determined as tricalcium silicate and dicalcium silicate in the three calcium silicate-based materials. We determined that the main components of the materials were similar. We also identified the extensive presence of tricalcium aluminate in MTA Angelus, calcium carbonate in Biodentine, and calcium phosphate salts in NeoMTA Plus. Furthermore, the results of the present particle analysis show that the calcium-silicate-based materials' distribution of particle count and size varies. Biodentine has the widest, and MTA Angelus has the narrowest particle size distribution range. NeoMTA Plus has the largest number of fine, large-sized particles (p < 0.0001), while MTA Angelus and Biodentine have a more homogeneous and non-statistically significant particle distribution range (p > 0.05). Conclusions: The present findings provide insight into variations in performance between different calcium-silicate-based materials.

Cell therapy: A potential solution for the healing of bone cavities

Aim

To Explore whether the use of autologous BMMNCs as a cell therapy technique will improve the healing of bone cavities in vivo.

Methodology

After achieving proper anesthesia, mononuclear cells were isolated from iliac crest's bone marrow aspirates (BMMNCs). Then access cavity, root canal preparation, and filling were done in third and fourth premolars, followed by amalgam coronal restoration. After that, a flap was reflected and a standardized bone cavity was drilled, the related root-ends were resected and retrocavity was drilled and filled with MTA. Before repositioning the flap, the bone cavity was filled with the desired filling material according to its corresponding group (n = 8): CollaCote group; where collagen scaffold was used, MNC group; in which CollaCote® loaded with isolated BMMNCs were applied, Biogen group; in which BIO-GEN® graft material was applied and finally Control group; where the bone cavities were left empty to heal spontaneously. Evaluations of healing of the bone cavities were done radiographically and histologically.

Results

The MNC group induced the best healing potential with statistical significant difference from other groups.

Conclusion

cell therapy utilizing autologous BMMNCs looks to beat the conventional therapies and convey a significant improvement in the healing of the bone cavity in vivo.

The use of photobiomodulation therapy or LED and mineral trioxide aggregate improves the repair of complete tibial fractures treated with wire osteosynthesis in rodents

The repair of large bone defects is lengthy and complex. Both biomaterials and phototherapy have been used to improve bone repair. We aimed to describe histologically the repair of tibial fractures treated by wiring (W), irradiated or not, with laser (λ780 nm, 70 mW, CW, spot area of 0.5 cm², 20.4 J/cm² (4 × 5.1 J/cm², Twin Flex Evolution®, MM Optics, Sao Carlos, SP, Brazil) per session, 300 s, 142.8 J/cm² per treatment) or LED (λ850 ± 10 nm, 150 mW, spot area of 0.5 cm², 20.4 J/cm² per session, 64 s, 142.8 J/cm² per treatment, Fisioled®^, MM Optics, Sao Carlos, Sao Paulo, Brazil) and associated or not to the use of mineral trioxide aggregate (MTA, Angelus®, Londrina, PR, Brazil). Inflammation was discrete on groups W and W + LEDPT and absent on the others. Phototherapy protocols started immediately before suturing and repeated at every other day for 15 days. Collagen deposition intense on groups W + LEDPT, W + BIO-MTA + LaserPT and W + BIO-MTA + LEDPT and discrete or moderate on the other groups. Reabsorption was discrete on groups W and W + LEDPT and absent on the other groups. Neoformation varied greatly between groups. Most groups were partial and moderately filed with new-formed bone (W, W + LaserPT, W + LEDPT, W + BIO-MTA + LEDPT). On groups W + BIO-MTA and W + BIO-MTA + LaserPT bone, neoformation was intense and complete. Our results are indicative that the association of MTA and PBMT (λ = 780 nm) improves the repair of complete tibial fracture treated with wire osteosynthesis in a rodent model more efficiently than LED (λ = 850 ± 10 nm).

Bioactive tri/dicalcium silicate cements for treatment of pulpal and periapical tissues

Over 2500 articles and 200 reviews have been published on the bioactive tri/dicalcium silicate dental materials. The indications have expanded since their introduction in the 1990s from endodontic restorative and pulpal treatments to endodontic sealing and obturation. Bioactive ceramics, based on tri/dicalcium silicate cements, are now an indispensable part of the contemporary dental armamentarium for specialists including endodontists, pediatric dentists, oral surgeons andfor general dentists. This review emphasizes research on how these materials have conformed to international standards for dental materials ranging from biocompatibility (ISO 7405) to conformance as root canal sealers (ISO 6876). Potential future developments of alternative hydraulic materials were included. This review provides accurate materials science information on these important materials. STATEMENT OF SIGNIFICANCE: The broadening indications and the proliferation of tri/dicalcium silicate-based products make this relatively new dental material important for all dentists and biomaterials scientists. Presenting the variations in compositions, properties, indications and clinical performance enable clinicians to choose the material most suitable for their cases. Researchers may expand their bioactive investigations to further validate and improve materials and outcomes.