Estudo biomecanico de tres tecnicas diferentes de fixações metalicas utilizadas em osteotomia sagital do ramo mandibular / Biomechanical evaluation of three different techniques of rigid fixation in sagital split ramus osteotomy

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

Studies have considered many techniques and methods of rigid internal fixation (RIF) leads to obtain greater stability to the bone segments and minimum displacement of the condyles after performed the sagittal split ramus osteotomy (SSRO). In this way, the purpose of this study was to evaluate by means of mechanical compression testing model with synthetic hemimandibles, three different fixation types used in the SSRO in movement of advance of 5 mm. Thirty hemimandibles, divided in 3 groups with 10 hemimandibles in each group. Group 1 was fixed with three 15 mm positional screws (2.0 mm diameter) bicortically in an inverted-L pattern and with insertion angle of 90°; in Group 2 the fixation was carried through with four-hole straight plate and four 6 mm monocortical screws made located on the region of the mandibular canal, and Group 3 the fixation is consisted of an adjustable sagittal plate and eight 6 mm screws also placed on the mandibular canal. Evaluated for dimensional standardization, the fixation system had demonstrated dimensional similarity. Hemimandibles had been exposed to the vertical compressive loads, by means of tip of load application in a MTS® mechanical testing unit, in the speed of 1 mm/min with maximum displacement of 10 mm. Averages and standard deviations had been obtained and submitted to the analysis of variance to a factor and have tested for HSD of Tukey test with a 5% level of significance. Group 1 presented greaters values of resistance to the compressive loads (p<0.001) showed superior to the other groups. Group 3 demonstrated the lesser resistance to the loading forces (p<0.001). It was concluded that the use of positional bicortical screws in inverted-L pattern promotes the higher capacities of resistance to compressive loads, moreover, the adjustable sagittal plates are presented about less resistant 60% that the Group 1

ASSUNTO(S)

bone plates placas osseas bone screws osteotomy osteotomia parafusos ósseos

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