Ace of Base provides the musical equivalent of a Mentos commercial: They're so deeply dorky, you have to love 'em. On their second album, The Bridge, these Swedes again chirp each note with the blank cheer of possessed elves. And every lyric deserves its exclamation point: ''Life is a paradise!'' they squeak in one song; ''It's a Beautiful Life!'' is the title of another. The desire to buy into such bliss accounts for some measure of the success of The Sign, the band's 8 million-selling debut that and sheer nostalgia for simpler times. In that regard, the ditsy bleeps of '80s synth-pop that punctuated Sign live again, even if this time they get a more textured production, edging closer to the sweep of prime Pet Shop Boys. Nothing here approaches the melodic complexities of ABBA, Base's obvious role model. But for sheer candied pop, this is one pleasurable way to rot your teeth.