Introduction: Orthodontic treatment for adults is currently increasing, and therefore the need to bond brackets to restorations and temporary crowns. The use of CAD/CAM PMMA provisional restorations for orthodontic purposes have not yet been described, and there is currently insufficient information regarding the strength of bracket adhesion. Objective: This study aimed at evaluating the effects of thermocycling (TC) and surface treatment on shear bond strength (SBS) of brackets to different provisional materials. Methods: Forty specimens were made from each material [PMMA (Telio Lab), bis-acryl (Telio CS C&B), and PMMA CAD/CAM (Telio CAD)], sandpapered, and divided according to surface treatment (pumiced or sandblasted) and TC (half of the samples = 1,000 cycles, 5°C/55°C water baths) (n = 10/group). Stainless-steel brackets were bonded to the specimens (using Transbond XT), and SBS testing was performed. Data were analyzed by three-way ANOVA and LSD post-hoc tests (α = 0.05). Failure types were classified with adhesive remnant index (ARI) scores. Results: SBS values ranged from 1.5 to 14.9 MPa. Sandblasted bis-acryl and sandblasted auto-curing PMMA groups presented similar values (p> 0.05), higher than the CAD/CAM material (p< 0.05), with or without TC. When thermocycled, pumiced bis-acryl showed higher SBS than pumiced acrylic (p= 0.005) and CAD/CAM materials (p= 0.000), with statistical difference (p= 0.009). TC showed negative effect (p< 0.05) for sandblasted bis-acryl and pumiced acrylic groups. ARI predominant score was mostly zero (0) for CAD/CAM, 1 and 2 for bis-acryl, and 1 for acrylic groups. Conclusion: In general, bis-acryl material showed the highest SBS values, followed by acrylic and CAD/CAM materials, which showed SBS values lower than an optimum strength for bonding brackets.
Resumen: Introducción: Las compresiones maxilares son una de las anomalías más frecuentes, independiente del tipo de dentición que se esté estudiando. Su tratamiento se puede realizar con un aparato expansor ya sea dentosoportado o esqueletalmente soportado, dependiendo de las consideraciones de maduración biológica del paciente. Se ha demostrado éxito en el tratamiento en etapas prepuberales, sin embargo, existe evidencia de una sutura abierta aún en etapas post adolescencia. El objetivo de este estudio es comparar, mediante Cone Beam CT, los efectos de un dispositivo de expansión rápida maxilar esqueletamente soportado, en relación a los dentosoportados, en adultos jóvenes con compresión maxilar. Material y método: Se realizó un estudio de tipo observacional retrospectivo, donde se evaluaron nueve pacientes (tres hombres y seis mujeres) con un promedio de edad de 18±5,5 años,que asistieron al Servicio de Ortodoncia de la Universidad de Chile, durante los años 2014-2015. Seis pacientes fueron tratados con aparatos dentalmente soportados (tipo Hyrax) y tres pacientes con apartos esqueletalmente soportados (MARPE). A través de CBCT se
REVISIÓN BIBLIOGRÁFICAEfecto del entrenamiento muscular masticatorio en el desarrollo del patrón vertical facial en niños: revisión narrativa.Training effect of the masticatory muscles in the development of the vertical facial pattern in children: narrative review.
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