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Analysis found that the middle assembly tip broke off at the spiral wrap and the inner spiral wrap was deformed which would have resulted in the reported event.The broken tip measured 0.45¿ with a piece of spiral wrap extending outward.There was uneven wear inside the middle assembly cutting mouth opening.There was grease on the inner assemblies as required by the drawing.There was deformation of the rotating hub consistent with improper loading the blade into the hand piece and excess pressure applied after being properly loaded: dimples on the front hub prior to the locking area caused by a misalignment of the hand piece locking mechanism, locking area deformation caused by the back side of the front collet of the hand piece, and elongation of the locking divots.Although there was hub deformation, the blade loaded properly into the hand piece.Although there was damage to both assemblies, the inner and middle assemblies spun freely by hand using the hubs which indicates there was no interference fit.There was no damage to the cutting teeth.If information is provided in the future, a supplemental report will be issued.
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