RESUMO
Composite resin is universally used for posterior teeth restorations. Fibers have been suggested for the mechanical improvement of the restorations. This study assessed the fracture resistance of class II fiber-reinforced composite restorations and compared it with the fracture resistance of three control groups: (1) healthy teeth, (2) non-fiber-reinforced restorations and (3) unrestored cavities. A search was performed using PubMed, Web of Science and Google Scholar from 15 May to 12 June 2023. Only in vitro studies from the last 10 years were included for this systematic analysis. This study was registered in the PROSPERO database, it followed PRISMA guidelines and the risk of bias was assessed using the QUIN tool. Fracture resistance median values, in Newtons (N), were calculated for the experimental and control groups (95% confidence interval). For pairwise comparison, nonparametric tests (p < 0.05) were applied. Twenty-four in vitro studies met the inclusion criteria. The fracture resistance of the experimental group was 976.0 N and differed (p < 0.05) from all controls. The experimental group showed lower values of fracture resistance than healthy teeth (1459.9 N; p = 0.048) but higher values than non-fiber-reinforced restorations (771.0 N; p = 0.008) and unrestored cavities (386.6 N; p < 0.001). In vitro systematic outcomes evidenced that glass and/or polyethylene fibers improved the fracture resistance of composite restorations.
RESUMO
La gran diversidad de descripciones acerca de las afluencias de las venas facial, lingual y tiroidea superior en el hombre, estas presentan una serie de controversias entre los autores investigados. Buscando ofrecer un patrón para la formación de troncos venosos a partir de las referidas venas, los autores realizaron la disecación de 42 faces laterales del cuello de cadáveres humanos adultos, de ambos sexos, con edades variadas y fijados en formaldehido a 10%. Se observó la formación de troncos venosos en 59,5% de los casos, habiendo ocurrido formación del tronco tiroilingofacial en 38,1%, del tronco lingofacial en 14,2%, del tronco tiroilingual en 4,8% y del tronco tiroilingofaringofacial en apenas 2,4%. No fue encontrada la formación del tronco tiroifacial descrito en la literatura. En los 40,5% de los casos en los que no hubo formación de troncos venosos, las venas presentaron desembocaduras solitarias.
Despite the great diversity of descriptions concerning the inflows of the facial, lingual and superior thyroid veins in man, they present important controversies between the studied authors. Aiming to supply a pattern for the formation of venous trunks by the cited veins, the authors analyzed 42 lateral faces of dissected adult human cadavers of both genders, different ages and preserved in a 10% solution of formaldehyde. The study revealed the formation of venous trunks in 59,5% of the cases, the thyroid-lingual-facial trunk appears in 38,1%, the lingual-facial trunk in 14,2%, the thyroid-lingual trunk in 4,8% and the thyroid-lingual-pharyngeal-facial trunk in just 2,4%. It was not found the formation of thyroid-facial trunk described in the analyzed literature. 40,5% of the cases appears with no venous trunk formation, in those situations the veins end alone.