Spanish to English Art/Literary Poetry & Literature

This comes in a short story from Argentina about a man who repairs satellites in orbit, and comes down to Earth to discover all the people have gone. One of his biggest fears is madness:
"La locura esperaba agazapada debajo de mi cama a que bajara la guardia. Me visitaba en sueños, harapienta y confusa, soplando un fagot desafinado, con dedos como trozos de hielo que lanzaban **dentelladas** al aire, pidiendo que por piedad la dejara acurrucarse en el espacio que ocupan los sueños detrás de los ojos."

I just can't quite work out what "dentelladas" here actually means. So far I have come up with:
"Madness was lying in wait under my bed for me to drop my guard. It visited me in dreams, ragged and confused, blowing an out-of-tune bassoon, with fingers like pieces of ice throwing **shards** into the air, asking for pity's sake to be allowed to curl up in the space behind my eyes occupied by my dreams."

Have I understood this right, and does anyone have anything better?