Efeitos do etil‐2‐cianoacrilato e do butil‐2‐cianoacrilato no processo de consolidação óssea em ratos. Estudo experimental controlado

Cyanoacrylate Adhesives for Cutaneous Wound Closure

Cyanoacrylate-based adhesives are widely used in wound closure, providing good cosmetic results and little discomfort. However, reports in the literature are found about negative effects that include the release of cytotoxic chemicals during biodegradation. In this study, we sought to evaluate and compare the effectiveness of four cyanoacrylate-based adhesives on the closure of skin incisions in Rattus norvegicus. The animals (n = 140) were divided into five groups of 28 animals each according to the wound closure technique: G1 and G2 (n-2-ethyl-cyanoacrylate); G3 (n-2-butyl-cyanoacrylate); G4 (n-2-octyl-cyanoacrylate); and G5 (5 nylon stitches). Midline incisions measuring 5.0 cm in length were created and closed using the different materials evaluated, and on D3, D7, D14, and D21, tensiometric and histopathological analyses were performed. Shorter wound closure and adhesion times were observed in G4 animals. At D3 and D7, G5 presented greater tensiometric resistance in the animals of G5, with a decrease in D14 and D21 compared to the other groups. On the other hand, the wounds of G3 and G4 were more resistant in D14 and D21, reaching maximum resistance values. Polymorphonuclear and mononuclear cells are more prevalent and more granulation tissue was observed in G5. The deposition of type III collagen was more evident in G5, whilst there was no difference in the amount of type I collagen in any of the groups treated with cyanoacrylate adhesives. Larger areas stained positive for VEGF-α in G2 and smaller areas in G4, with peaks at D7 and D14. In general, cyanoacrylate adhesives cause less intense inflammatory reactions, resulting in shorter healing times when compared to nylon sutures.

In vitro effect of Er: YAG laser irradiation in caries cavity preparation on biobehaviors of adjacent human dental pulp cells in the pulp chamber

The erbium-doped yttrium aluminum garnet (Er: YAG) laser has been successfully applied in caries removal; however, little is known about proper parameters of Er: YAG laser on different conditions of caries removal, especially the influence of Er: YAG irradiation on human dental pulp cells (hDPCs). Here, we tested the effects of Er: YAG laser at different output energy levels (100, 200, 300, 400, and 500 mJ) on biobehaviors of hDPCs. To simulate clinical deep caries conditions, hDPCs were cultured on the pulpal side of 500-μm-thick dentin disks in an in vitro pulp chamber model. Temperature change, structural change, and ablation depth of dentin disk were also recorded. The findings suggested that the biological behaviors of hDPCs are strongly correlated with the energy output of the Er: YAG laser. Er: YAG laser irradiation at 100 mJ may be proper and safe for deep caries removal since it would not cause any adverse effect on hDPCs biobehaviors.

Bioactive Pore-Forming Bone Adhesives Facilitating Cell Ingrowth for Fracture Healing

The effectiveness of commercial bone adhesives is known to be hampered by the weak efficacy of cell ingrowth. The strategy of macropore-forming, especially bioactive macropores, holds considerable promise to circumvent this problem, thereby promoting fracture healing. Herein, a class of bioactive glass-involved macropore-embedded bone adhesives is developed, which is capable of facilitating the migration of bone-derived mesenchymal stromal cells into the adhesive layer and differentiation into osteocytes. The integration of bioactive glass-particle-encapsulated porogens in the bone adhesives is key to this approach. A robust instant bonding on the bone adhesive and a high efficiency of bone regeneration on a mouse skull are observed, both of which are vital for clinical applications and personalized surgical procedures. This work represents a general strategy to design biomaterials with high cell-ingrowth efficacy.

Reposition of the bone plate over the antrostomy in maxillary sinus augmentation: A histomorphometric study in rabbits

OBJECTIVE

To test if repositioning the bony plate secured with a cyanoacrylate over the antrostomy in maxillary sinus augmentation was superior to covering the antrostomy with a collagen membrane in terms of the bone augmentation area and the bone density.

MATERIAL AND METHODS

After the exposure of the nasal bone in eighteen rabbits, a rectangular access window was prepared with a sonic instrument, and the bony plate was removed. A bilateral sinus mucosa elevation was performed, and the space was filled with a resorbable xenograft. On the test side, the bone plate was repositioned over the antrostomy and fixed with a cyanoacrylate. On the control side, a collagen membrane was placed over the opening. Per group, six animals were sacrificed after 2, 4, and 8 weeks of healing, respectively. Histological ground sections were prepared.

RESULTS

The augmented area after elevation decreased between 2 and 8 weeks from 9.4 ± 1.8 to 4.8 ± 2.8 mm² at the test and from 9.5 ± 2.6 and 5.1 ± 1.6 mm² at the control sites. Small amounts of new bone were seen after 2 weeks in both groups (~1.6%-2.5%) forming from the bony sinus walls. New bone density increased over time in both groups reaching ~ 10%-11% and ~ 23%-25% after 4 and 8 weeks, respectively. No statistically significant differences were found. Small residual defects were present both at the test sites in the margin of the bone plate, and at the control sites in the center of the antrostomy.

CONCLUSIONS

The bone healing in the elevated sinus space was similar irrespective of the coverage of the antrostomy. After 8 weeks, the bone plate repositioned on the antrostomy was incorporated while at the control sites the healing was still incomplete. Residual defects were still present in both groups.