The influence of the pilot hole depth in the pull-out strength of pedicle screws with a conical inner diameter and parallel threads - A study of full insertion A influência da profundidade do orifício piloto na força para arrancamento de parafusos de pedículo com alma cônica e roscas paralelas - Um estudo com a sua inserção total
Tipo
Artigo
Data de publicação
2008
Periódico
Coluna/ Columna
Citações (Scopus)
0
Autores
Nied R.
Pudles E.
da Rocha L.E.M.
Sanzovo N.
Suzuki L.Y.
Pudles E.
da Rocha L.E.M.
Sanzovo N.
Suzuki L.Y.
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Resumo
Objective: The objective of this study is to compare whether the depth of the pilot hole influence in the pull out strength of pedicle screws with a conical inner diameter and parallel threads. Methods: a total of 27 titanium pedicle screws with 40, 45 and 50mm of length (9 of each) are installed in different depth pilot holes (with 40, 45 or 50mm of depth). The holes where drilled an a uniform synthetic material (Polyurethane Foam) to provide a consistent test of each screw, then loaded to failure. Results: When we compare in the analysis of the 40mm and the 50mm screws, in the 40mm depth hole, the 50mm screw has his pullout strength increased (p = 0, 005). In the same way, when the 45mm screw with the 50mm screw in the 45mm pilot hole, the 50mm screw has his pullout strength increased (p = 0,01). In another way, when we compare the 40mm screw with the 50mm screw in the 50mm hole, the 40mm screw has lower strength (p = 0,01). Conclusion: If a bigger screw is used in a smaller depth pilot hole there is a significantly greater pullout strength; besides in some cases, a smaller screw in a bigger pilot hole, decrease significantly the pullout strength.