Hybrid surface implants: Influence of residual stress on mechanical behavior, evaluated by finite element analysis and validation by fatigue tests.

OBJECTIVES: To determine the influence of different surface roughness and residual stress of hybrid surface implants on their behavior and mechanical failure. METHODS: Three types of implants with different surface roughness were used as specimens: smooth, rough, and hybrid. A diffractometer was used to determine the residual stress of the implants according to their different surface treatment. These results were used as an independent variable in a finite element analysis that compared the three specimens to determine the von Mises stress transferred to the implants and supporting bone and the resulting microdeformations. Flexural strength and fatigue behavior tests were performed to compare the results of the three types of implants. RESULTS: Higher residual stress values were found for rough surfaces (p < 0.05, Student's t-test) compared to smooth surfaces, and both types of stress were different for the two types of hybrid implant surfaces. Finite element analysis found different von Mises stress and microdeformation results, both at the level of the implant and the bone, for the three types of implants under study. These results were correlated with the different flexural strength behaviors (lower resistance for hybrids and higher for rough surfaces, p < 0.05) and fatigue behavior (the rough implant had the longest fatigue life, while the hybrid implant exhibited the worst fatigue behavior). SIGNIFICANCE: The results show a trend toward a less favorable mechanical behavior of the hybrid implants related to the retention of different residual stresses caused by the surface treatment.

Inyecciones Intraarticulares de Ácido Hialurónico como Alternativa a los Corticoesteroides enel Tratamiento de la Osteoartritis de la Articulación Témporomandibular: Estudio de Revisión Sistemática / Intraarticular Injections of Hyaluronic Acid as an Alternative to Corticosteroids in the Treatment of Osteoarthritis of the Temporomandibular Joint: Study of Systematic Review

El objetivo de este trabajo fue determinar la disminución del dolor y la mejora de la función en los procesos artrósicos de la ATM mediante el empleo de hialuronato de sodio o corticoides. Realización de una revisión sistemática conforme a la metodología PICO del Centro de Medicina Basada en la Evidencia de Oxford. Se formula una pregunta dirigida al objetivo fijado y se elabora una estrategia de búsqueda, empleando términos MeSH y palabras clave específicas derivados de la pregunta en la base de datos de MEDLINE de enero de 1985 hasta abril del 2016. Se consultan un total de 43 artículos, incluyendo finalmente 7 estudios clínicos controlados y aleatorizados que cumplían los criterios de inclusión y se realiza una evaluación crítica del nivel de evidencia. Se estudiaron trabajos que comparasen la eficacia del hialuronato de sodio con los corticoides en la inyección articular de las patologías artrósicas de la ATM. No se encontraron diferencias significativas en la realización de la inyección con hialuronato de sodio y corticoides. Es necesario realizar estudios con una muestra y un tiempo de seguimiento mayor. A largo plazo podría ser más eficaz el hialuronato de sodio debido a los posibles efectos adversos de los corticoides, sin embargo, no se han demostrado cambios óseos con ninguno de los tratamientos.

The aim of this study was to determine decreasing pain and improving function in TMJ osteoarthritic processes using sodium hyaluronate or corticosteroids. A systematic review was carried out based on the PICO methodology of the Centre for Evidence-Based Medicine in Oxford. A question is addressed to the fixed aim and a search strategy is developed using specific MeSH terms and key words which come from the question in the PubMed database from January 1985 to April 2016. A total of 43 articles are consulted, finally including 7 randomized controlled trials which met the inclusion criteria and a critical assessment of the level of evidence is performed. Works that compare the efficacy of sodium hyaluronate to corticosteroids in the osteoarthritic pathologies articular injection were studied. No significant differences were found when injecting the sodium hyaluronate and the corticosteroids. It is necessary to do studies with a broader sample and a longer follow-up. In the long term sodium hyaluronate could be more effective because of possible corticosteroids adverse effects; however, no bone change has been shown with either treatment.