Each of us needs to be ambassadors for Dentistry within our own practices, and at church, athletic and social events.
( ( Each ( of us ) ) ( ( needs ( to ( be ( ( ambassadors ( for Dentistry ) ) ( ( ( ( within ( our ( own practices ) ) ) , ) and ) ( at ( church ( , ( athletic ( and ( social events ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT Each)) (PP (IN of) (NP (PRP us)))) (VP (VBZ needs) (S (VP (TO to) (VP (VB be) (VP (VBN ambassadors) (PP (IN for) (NP (NNP Dentistry))) (PP (PP (IN within) (NP (PRP$ our) (JJ own) (NNS practices))) (, ,) (CC and) (PP (IN at) (NP (NN church) (, ,) (JJ athletic) (CC and) (JJ social) (NNS events))))))))) (. .)))
There is a need for all of us to disregard promoting Dentistry. 
( There ( ( is ( ( ( a need ) ( for ( all ( of us ) ) ) ) ( to ( disregard ( promoting Dentistry ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBZ is) (NP (NP (DT a) (NN need)) (PP (IN for) (NP (NP (DT all)) (PP (IN of) (NP (PRP us))))) (S (VP (TO to) (VP (VB disregard) (S (VP (VBG promoting) (NP (NNP Dentistry))))))))) (. .)))