En conductos radiculares curvos, la utilización de limas que eviten desvíos y fracturas del instrumento por fatiga y que mantengan curvaturas originales son aspectos importantes en el tratamiento endodóntico. Objetivo: Se evaluó la resistencia a la fatiga cíclica de cuatro sistemas reciprocantes en una canaleta dinámica que simuló tres curvaturas diferentes. Materiales y Método: Estudio in vitro; la muestra con 48 limas se dividió en cuatro grupos (n= 12/grupo): WaveOne® (WO), WaveOne® Gold (WOG), Reciproc® (R) y Reciproc® Blue (RB), cuatro limas de cada sistema se usaron en una canaleta que simuló tres angulaciones 45°, 60° y 90°; montadas en un motor X-Smart Plus®, las limas se introdujeron 23 mm en los conductos para ser activadas continuamente a 300/500 oscilaciones/minuto hasta que se produjo la fractura. Se registró tiempo y zona de fractura. Se realizó el test Kruskal Wallis con un nivel de confianza del 95% para las comparaciones. Resultados: RB presentó mayor resistencia a la fatiga cíclica que WO y WOG en todas las angulaciones y que R a 90° (p= <0,05). R presentó mayor resistencia que WOG a 45° y 60°, sin embargo, a 90° WOG fue superior que R y WO (p<0,05). No hubo diferencias en cuanto a la zona de fractura que aconteció en la porción apical. Conclusiones: La resistencia se reduce cuando aumenta el grado de curvatura. RB fue significativamente más resistente a la fatiga cíclica que WO y WOG en todas las angulaciones y que R a 90°. La zona de fractura se produjo en la porción apical de las limas.

Araujo, PDH. Gene expression of BMPR1, BMPR2 and TGFBR1 released from human dentin disks treated with different demineralizing solutions and adhesion of cultured apical papilla cells [thesis]. São Paulo: Universidade de São Paulo, Faculdade de Odontologia; 2018. Versão Original. The success of regenerative endodontic procedures depends on the proper disinfection of the root canal, the presence of undifferentiated mesenchymal cells, the release of growth factors that act as signaling molecules for attraction, proliferation, cell differentiation and the presence of a scaffold that provides support for the organization and vascularization of neoformed tissue. Pulp regeneration protocols have used EDTA to remove the smear layer and release growth factors present in the dentin matrix. A few studies have analyzed whether the use of calcium-specific chelating or less aggressive solutions have better results in the release of growth factors and the adhesion of apical papilla cells to the dentin surface. The objective of this study was to evaluate the gene expression of BMPR1, BMPR2 and TGFBR1 released from human dentin disks previously treated with EDTA, EGTA and Citric Acid and the adhesion of apical papilla cells to these disks. Cryopreserved cells from the cell biorepository of the Basic Biology Laboratory of the Department of Dentistry of the Faculty of Dentistry of the University of São Paulo were used. Dentin discs were obtained from the inner root portion of premolars and human third molars that were obtained from the Biobank of the Human Tooth Division (FOUSP). After 1 min immersion in the demineralizing solutions the discs were transferred to plaques and the cells were plated. The cell adhesion was evaluated after 48 hours using the Scanning Electron Microscopy. Gene expression was determined after the periods of 7 and 21 days of cell culture. Statistical analysis was performed by analysis of variance at 1 criterion (ANOVA) followed by Tukey test post, with a significance level of 5%. At 21 days treatment of dentin with EGTA resulted in a significant increase of BMPR1 compared to PBS. No experimental condition altered BMPR2 expression. The expression of TGBR1 at 21 days was significantly increased by pretreatment of the EGTA discs. Although there was no uniform distribution of cells along the discs, cell adhesion was observed in all experimental groups. It is concluded that the type of demineralizing solution interferes with the released amount of the BMPR1 and TGFBR1 growth factors present in the human dentin, not interfering in the adhesion of apical papilla cells to the dentinal surface.

Expresión génica de BMPR1, BMPR2, y TGFBR1 en dentina humana tratados con diferentes soluciones desmineralizantes y adhesión de las células de papila apical cultivada Gene expression of BMPR1, BMPR2, and TGFBR1 in human dentin treated with different demineralizing solutions and adhesion of cultured apical papilla cells