Pro-angiogenic potential of a functionalized hydrogel scaffold as a secretome delivery platform: An innovative strategy for cell homing-based dental pulp tissue engineering.

Angiogenesis is a key process that provides a suitable environment for successful tissue engineering and is even more crucial in regenerative endodontic procedures, since the root canal anatomy limits the development of a vascular network supply. Thus, sustainable and accelerated vascularization of tissue-engineered dental pulp constructs remains a major challenge in cell homing approaches. This study aimed to functionalize a chitosan hydrogel scaffold (CS) as a platform loaded with secretomes of stem cells from human exfoliated deciduous teeth (SHEDs) and evaluate its bioactive function and pro-angiogenic properties. Initially, the CS was loaded with SHED secretomes (CS-S), and the release kinetics of several trophic factors were assessed. Proliferation and chemotaxis assays were performed to analyze the effect of functionalized scaffold on stem cells from apical papilla (SCAPs) and the angiogenic potential was analyzed through the Matrigel tube formation assay with co-cultured of human umbilical vein endothelial cells and SCAPs. SHEDs and SCAPs expressed typical levels of mesenchymal stem cell surface markers. CS-S was able to release the trophic factors in a sustained manner, but each factor has its own release kinetics. The CS-S group showed a significantly higher proliferation rate, accelerated the chemotaxis, and higher capacity to form vascular-like structures. CS-S provided a sustained and controlled release of trophic factors, which, in turn, improved proliferation, chemotaxis and all angiogenesis parameters in the co-culture. Thus, the functionalization of chitosan scaffolds loaded with secretomes is a promising platform for cell homing-based tissue engineering.

Effect of human dental pulp stem cell conditioned medium in the dentin-pulp complex regeneration: A pilot in vivo study.

BACKGROUND: Dental trauma, restorative operative procedures and/or caries lesions can expose the dental pulp. Facing this clinical condition, where the maintenance of the dentin-pulp complex vitality is imperative, is challenging in Dentistry. Dental pulp stem cells conditioned medium contains trophic factors that could help in this task. This in vivo pilot study aimed to evaluate the effects of the human dental pulp stem cells conditioned medium on the dental pulp tissue response to vital pulp therapy. MATERIAL AND METHODS: Concentrated conditioned medium was obtained by incubating characterized human dental pulp stem cells with fresh culture medium. Pulp exposures performed at the first upper molars (n = 20) of Wistar rats were directly capped with: MTA or MTA + Conditioned Medium. Four and 8 weeks later, the samples were qualitatively analyzed in histological sections (H&E). RESULTS: When the conditioned medium was associated with MTA, there were a high percentage of samples presenting formation of dentin bridges and small percentage of pulp tissue with inflammatory signs in both experimental times. The conditioned medium improved the organization of the newly formed hard tissue. CONCLUSIONS: The association of dental pulp stem cell conditioned medium with MTA showed beneficial effects on dentin-pulp complex regeneration and has promising potential for studies in regenerative dentistry.

Physical and Biological Properties of a Chitosan Hydrogel Scaffold Associated to Photobiomodulation Therapy for Dental Pulp Regeneration: An In Vitro and In Vivo Study.

BACKGROUND: The regeneration of dental pulp, especially in cases of pulp death of immature teeth, is the goal of the regenerative endodontic procedures (REPs) that are based on tissue engineering principles, consisting of stem cells, growth factors, and scaffolds. Photobiomodulation therapy (PBMT) showed to improve dental pulp regeneration through cell homing approaches in preclinical studies and has been proposed as the fourth element of tissue engineering. However, when a blood clot was used as a scaffold in one of these previous studies, only 30% of success was achieved. The authors pointed out the instability of the blood clot as the regeneration shortcoming. Then, to circumvent this problem, a new scaffold was developed to be applied with the blood clot. The hypothesis of the present study was that an experimental injectable chitosan hydrogel would facilitate the three-dimensional spatial organization of endogenous stem cells in dental pulp regeneration with no interference on the positive influence of PBMT. METHODS: For the in vitro analysis, stem cells from the apical papilla (SCAPs) were characterized by flow cytometry and applied in the chitosan scaffold for evaluating adhesion, migration, and proliferation. For the in vivo analysis, the chitosan scaffold was applied in a rodent orthotopic dental pulp regeneration model under the influence of PBMT (660 nm; power output of 20 mW, beam area of 0.028 cm2, and energy density of 5 J/cm2). RESULTS: The scaffold tested in this study allowed significantly higher viability, proliferation, and migration of SCAPs in vitro when PBMT was applied, especially with the energy density of 5 J/cm2. These results were in consonance to those of the in vivo data, where pulp-like tissue formation was observed inside the root canal. CONCLUSION: Chitosan hydrogel when applied with a blood clot and PBMT could in the future improve previous results of dental pulp regeneration through cell homing approaches.

Influencia de la medicación intracanal con pasta de hidróxido de calcio en la penetración del cemento obturador / obturadorInfluence of intracanal medication with calcium hydroxide paste in the penetration of the shutter cement / Influência da medicação intracanal com pasta de hidróxido de cálcio na infiltração do cimento obturador

La eliminación del hidróxido de calcio en el conducto radicular es determinante para el éxito del tratamiento endodóntico, los remanentes pueden interaccionar negativamente con los selladores endodónticos aumen-tando las filtraciones y disminuyendo la calidad de la obturación. Objetivo: Evaluar el efecto de la medicación intraconducto con pasta de hidróxido de calcio en la penetración del cemento obturador en el interior de los túbulos dentinarios. Materiales y métodos: 20 raíces distales de molares superiores se instrumentaron uti-lizando el Sistema Wave One Large 40/.08. Se dividieron aleatoriamente en dos grupos: uno obturado con técnica de cono único y cemento Ah plus con rodamina-B y otro obturado con la misma técnica y cemento Ah plus con rodamina B, previa colocación por 15 días y remoción mediante recapitulación de la pasta de hidróxido de calcio. Posteriormente los dientes fueron cortados transversalmente y se realizaron fotomicro-grafías del tercio cervical, medio y apical a través de la técnica de microscopia confocal de barrido por láser. La profundidad máxima de penetración fue determinada a través del programa Image J. Resultados: El ce-mento sellador Ah plus presentó menores valores de penetración cuando fue empleada previamente la pasta de hidróxido de calcio como medicación intracanal (p<0,01). El tercio del conducto con mayor penetración fue el tercio cervical seguido por el tercio medio y por último el apical (p<0,01). Conclusión: Los remanentes de hidróxido de calcio disminuyen la penetración del cemento sellador Ah plus en los túbulos dentinarios en todos los tercios del conducto radicular.

The elimination of calcium hydroxide in the root canal is decisive for the success of endodontic treatment, the remnants can interact negatively with endodontic sealants increasing filtrations and decreasing the quality of the seal. Objective: To evaluate the effect of intra-duct medication with calcium hydroxide paste on the pen-etration of the sealing cement inside the dentinal tubules. Materials and methods: 20 distal roots of upper molars were instrumented using the Wave One Large 40 / .08 System. They were randomly divided into two groups: one sealed with a single cone technique and Ah plus cement with rhodamine-B and another sealed with the same technique and Ah plus cement with rhodamine B, previous placement for 15 days and removal by recapping the paste calcium hydroxide. Subsequently, the teeth were cut transversely and photomicro-graphs of the cervical, middle and apical third were performed using the laser scanning confocal microscopy technique. The maximum depth of penetration was determined through the Image J program. Results: The Ah plus sealing cement had lower penetration values when the calcium hydroxide paste was previously used as an intra-channel medication (p <0.01). The third of the duct with the highest penetration was the cervical third followed by the middle third and finally the apical (p <0.01). Conclusion: Remaining calcium hydroxide decreases the penetration of the sealing cement Ah plus in the dentinal tubules in all thirds of the root canal.

A eliminação do hidróxido de cálcio do canal radicular é determinante para o sucesso do tratamento endo-dôntico; os remanescentes podem interagir negativamente com os cimentos endodônticos, aumentando as filtrações e diminuindo a qualidade do selamento. Objetivo: Avaliar o efeito da medicação intracanal com pasta de hidróxido de cálcio na penetração do cimento de selamento no interior dos túbulos dentinários. Materiais e métodos: 20 raízes distais de molares superiores foram instrumentadas usando o sistema Wave One Large 40 /.08. Eles foram divididos aleatoriamente em dois grupos: um selado com técnica de cone único mais cimento Ah plus com rodamina-B e outro selado com a mesma técnica e cimento Ah plus com rodami-na-B, prévia colocação por 15 dias e remoção recolocação da pasta hidróxido de cálcio. Posteriormente, os dentes foram cortados transversalmente e fotomicrografias do terço cervical, médio e apical foram realizadas pela técnica de microscopia confocal de varredura a laser. A profundidade máxima de penetração foi de-terminada pelo programa Image J. Resultados: O cimento selante Ah plus apresentou menores valores de infiltração quando a pasta de hidróxido de cálcio foi utilizada anteriormente como medicamento intracanal (p <0,01). O terço do conduto com maior penetração foi o terço cervical, seguido pelo terço médio e finalmente o apical (p <0,01). Conclusão: O hidróxido de cálcio restante diminui a penetração do cimento selante Ah plus nos túbulos dentinários em todos os terços do canal radicular.