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Praise be to Allaah, and peace and blessings be upon His Messenger.
May Allaah reward you for your question.
Regarding the effusion of blood from between the teeth, it does not nullify the wudoo' as long as it is minor (i.e. not profuse or a large amount), even if one ejects it from his mouth.
Allaah knows what is best and most correct.
Sheikh Muhammed Salih Al-Munajjid