Moody and Mammoth

"like teeth without lips
to cover them"

I've just had a lengthy internal devate debate about this, so maybe someone can help me here...
My first thought about these two lines was "like teeth without lips" - period.
"to cover them", to my ears/eyes/imagination, detracted from the image, reduced the dramatic impact, trailed it off after the image had already been established.
Next thought - yes, but teeth don't 'have' lips (two anatomically separate entities), so the qualification is necessary.
Finally - yes/no, but...does poetry require such specificity? We are looking at a facial metaphor here, and surely everyone, whether consciously or un/subconsciously, recognises the association between teeth and lips in that context(?). So, is that a valid conclusion? Or am I just descending into anal retentive territory here?

Oh yeh, sorry...hi Michael Good subject matter, with a distinct undertow of cynicism...I'd be interested to know what the 'Mammoth' in the title refers to [Anstey having cleared up the 'Moody' reference - thank you sweaty :]
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