RESUMO
Background and Objectives: Although fiber posts are widely used in the restoration of endodontically treated teeth (ETT), their ideal cementation depth into the root canal is still debated in literature. The aim of the present study was to evaluate whether the different intra-radicular insertion lengths of the fiber posts influence the fracture strength of ETT. Materials and Methods: A total of 10 permanent human lower incisors with straight roots of similar length and volume extracted for periodontal reason were sectioned 2 mm above the cement-enamel junction (CEJ) to a total length of 18 mm and endodontically treated in the same manner, then randomly divided into two groups of five each (Groups 1 and 2, n = 5). Two sound incisors, with no endodontic treatment, were used as the control group (Group 3, n = 2). After one week of storage in a humid environment, spaces for fiber post no. 1 (Reforpost, Angelus, Londrina, PR, Brazil) were prepared in the first two groups at a depth of 5 mm (Group 1) and 7 mm (Group 2), and the fiber posts were adhesively cemented using self-adhesive resin cement (Maxcem Elite, Kerr GmbH, Herzogenrath, Germany). After 7 days, the samples were vertically positioned and fixed in a self-curing transparent acrylic resin, up to 2 mm below the CEJ level, and mechanically tested in compression after another week of storage using a displacement-controlled testing machine up to each sample's fracture. The force-displacement curves were recorded for each sample, the means were calculated for each group and a statistical comparative analysis between groups was conducted. Results: Although no statistically significant differences between groups were observed, the highest mean fracture force (N) was recorded in Group 2 (1099.41 ± 481.89) in comparison to Group 1 (985.09 ± 330.28), even when compared to the sound, non-treated teeth (1045.69 ± 146.19). Conclusions: Within the limitations of this in vitro study, teeth where fiber posts were placed deeper into the root canal (7 mm) recorded slightly higher fracture forces in comparison with shorter lengths (5 mm). However, similar biomechanical performances obtained in the mechanical tests showed no statistical differences between the 7 mm and the 5 mm inserted posts.
Assuntos
Fraturas dos Dentes , Dente não Vital , Humanos , Resistência à Flexão , Resinas Compostas , Dente não Vital/terapia , IncisivoRESUMO
Background. Infantile hemangiomas may have unexpected behavior. Initial regression (spontaneously or drug-induced) may be followed by unexplained recurrences. At this moment, there are no well-established criteria to predict infantile hemangioma reccurrences. Methods. We compared the VEGF pathway gene expression profile for one case of involuting infantile hemangioma versus one case of recurrent proliferative infantile hemangioma using TaqMan Array. Results. We found ten genes upregulated for both involuting and recurrent proliferative hemangiomas: ACTB, KRAS, MAP2K1, HRAS, NOS3, BAD, HSPB1, HPRT1, GUSB, and CASP9. Thirteen genes were downregulated for both involuting and proliferative hemangiomas: FIGF, ACTG1, GRB2, MAPKAPK2, ACTG2, MAP2K2, MAPK3, HSP90AA1, MAP2K6, NRAS, ACTA1, KDR, and MAPK1. Three genes showed divergent expression between proliferating and involuting hemangiomas. Proliferating hemangioma had MAPK14 and AKT1 gene upregulation and ACTA2 downregulation. Involuting infantile hemangioma was characterized by ACTA2 upregulation and AKT1 and MAPK14 downregulation. Conclusions. Three genes, AKT1, p38/MAPK14, and ACTA2, were found to have divergent expression in proliferating and involuting infantile hemangiomas. Excepting AKT1, which was mentioned in the last ISSVA classification (strictly related to Proteus Syndrome), none of the other genes were reported. An accurate gene expression profile mapping of infantile hemangiomas together with a gene expression-based hemangioma classification is stringently needed.
RESUMO
Optical coherence tomography (OCT) is a non-invasive, non-radioactive optical diagnostic method based on low-coherence interferometry, which achieves images with different orientation. In dentistry, its major advantage is represented by the localization and characterization of the smallest defects in hard dental tissues, dental materials and of the smallest details in dental anatomy (supplementary canals, recesses, isthmuses, or intra-radicular connections). The aim of the present in vitro study was to evaluate using c-scan en-face optical coherence tomography, the optical opacity, and the distribution inside the root canal lumen of several extracted human teeth of silver and gold nanoparticles from special irrigating solutions used in endodontic treatment. Twelve root canals from 5 human teeth were instrumented using the ProTaper Universal system after initial negotiation with hand K-files ISO no. 10 and rotary nickel-titanium PathFile instruments. An initial c-scan OCT analysis was performed for each sample to confirm that the root canal lumen was empty from radiopaque materials (Group 1). Teeth were first irrigated with NanoCare Plus (Group 2) and then with NanoCare Gold (Group 3) and C-scans were repeated after each irrigation method. The OCT investigation started at the tooth apex, at a depth of 1 mm from its tip. Subsequently, 100 slices of 10 microns were obtained from each root canal. Images were captured and then analyzed with ImageJ software to calculate the level of grey inside the root canal lumen. The highest values of grey were obtained in the samples irrigated with NanoCare Gold after NanoCare Plus (Group 3). The present study proved that both nanoparticles inserted in root canal irrigants were evidenced through OCT imagistic analysis due to their optical opacity, which allowed their highlighting in an empty root canal lumen, after the endodontic treatment was performed and the root canal was cleaned and shaped using specific protocols.
