Avaliação in vitro do uso de uma miniplaca convencional e locking, de 4 e 7 furos, para tratamento das fraturas de ângulo mandibular
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Data
2008-05-06
Autores
Ribeiro Júnior, Paulo Domingos [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Este estudo avaliou in vitro a influência do tipo de miniplaca (convencional ou locking) e do número de parafusos instalados no segmento ósseo distal e proximal para a promoção da estabilidade óssea e resistência da osteossínteses pelo método Champy, utilizada para o tratamento de fraturas de ângulo mandibular. Sessenta hemi-mandíbulas de poliuretano, com consistência similar ao osso mandibular, foram divididas em 4 grupos (n=15) e seccionadas na região de ângulo mandibular simulando uma fratura. Os segmentos ósseos foram fixados por diferentes tipos de miniplacas usando sistema 2.0- mm e parafusos monocorticais de 2.0 x 6.0mm. Nos grupos 1 e 2, dois parafusos convencionais (G1) ou locking (G2) foram instalados em cada segmento ósseo usando respectivamente miniplacas retas convencionais e locking; Nos grupos 3 e 4, três parafusos convencionais (G3) ou locking (G4) foram instados no segmento ósseo proximal e quatro parafusos convencionais (G3) ou locking (G4) foram instalados no segmento distal, usando uma miniplaca convencional (G3) e locking (G4) de sete furos, reta. As hemi-mandíbulas foram submetidas a um teste de compressão utilizando uma máquina universal de ensaio INSTRON até que houvesse um distanciamento entre os segmentos ósseos de 4 mm, seja no sentido horizontal ou vertical. Os dados registrados foram submetidos à avaliação estatística pelo método ANOVA e teste de Tukey utilizando um nível de significância de 1%. As miniplacas locking ofereceram maior resistência ao teste de compressão do que as miniplacas convencionais (p<0.01). Porém, não existiu diferença entre o uso de miniplacas de 7 ou 4 furos (p>0.01). Apesar de não estatisticamente significante os resultados numéricos sugeriram que as miniplacas locking longas oferecem maior resistência ao teste de compressão que as miniplacas locking curtas.
This study evaluated in vitro the influence of the type of miniplate (conventional or locking) and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy’s osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to 4 groups (n=15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0-mm miniplates and 2.0 x 6 mm monocortical screws: Groups 1 and 2- Two conventional (G1) or locking (G2) screws were installed in each bone segment using either a conventional (G1) or a locking (G2) straight miniplate; Groups 3 and 4- Three conventional (G3) or locking (G4) screws were installed in the proximal segment and four conventional (G3) or locking (G4) screws were installed in the distal segment using a either a conventional (G3) or a locking (G4) 7-hole straight miniplate. The hemimandibles were loaded in compressive strength in an Instron machine until a 4-mm displacement occurred between the segments either vertically or horizontally. Data were analyzed statistically by ANOVA and Tukey’s test at 1% significance level. The locking plate/screw systems provided significantly greater resistance to displacement under compressive load than the conventional plate/screw systems (p<0.01). However, no statistically significant difference was found between 7-hole and 4-hole miniplates (p>0.01). In conclusion, the locking miniplates offered more resistance than conventional miniplates and long locking miniplates provided greater (number results) bone stability compared to short ones.
This study evaluated in vitro the influence of the type of miniplate (conventional or locking) and the number of screws installed in the proximal and distal segments on the stability and resistance of Champy’s osteosynthesis in mandibular angle fractures. Sixty polyurethane hemimandibles with bone-like consistency were randomly assigned to 4 groups (n=15) and sectioned in the mandibular angle region to simulate fracture. The bone segments were fixed by different osteosynthesis methods using 2.0-mm miniplates and 2.0 x 6 mm monocortical screws: Groups 1 and 2- Two conventional (G1) or locking (G2) screws were installed in each bone segment using either a conventional (G1) or a locking (G2) straight miniplate; Groups 3 and 4- Three conventional (G3) or locking (G4) screws were installed in the proximal segment and four conventional (G3) or locking (G4) screws were installed in the distal segment using a either a conventional (G3) or a locking (G4) 7-hole straight miniplate. The hemimandibles were loaded in compressive strength in an Instron machine until a 4-mm displacement occurred between the segments either vertically or horizontally. Data were analyzed statistically by ANOVA and Tukey’s test at 1% significance level. The locking plate/screw systems provided significantly greater resistance to displacement under compressive load than the conventional plate/screw systems (p<0.01). However, no statistically significant difference was found between 7-hole and 4-hole miniplates (p>0.01). In conclusion, the locking miniplates offered more resistance than conventional miniplates and long locking miniplates provided greater (number results) bone stability compared to short ones.
Descrição
Palavras-chave
Mandíbula - Fraturas, Traumatologia, Fraturas - Fixação interna, Placas ósseas, Traumatology, Mandibular fractures, Bone plates, Fracture fixation, internal
Como citar
RIBEIRO JÚNIOR, Paulo Domingos. Avaliação in vitro do uso de uma miniplaca convencional e locking, de 4 e 7 furos, para tratamento das fraturas de ângulo mandibular. 2008. 43 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Odontologia de Araçatuba, 2008.