Cloak of Fangs
Aura moderate transmutation; CL 9th
Slot shoulders; Price 2,800 gp; Weight 1 lb.
Wearing this animal-hair cloak grants a +1 resistance bonus on saving throws and a +2 enhancement bonus to CHA. Furthermore, the wearer can force his teeth to grow rapidly up to five times per day as a swift action. The oversized teeth last for 1 round, during which time the wearer can make a bite attack. Treat this attack as a primary natural attack that deals 1d6 points of damage (or 1d4 if the wearer is Small). If the wearer already has a bite attack, the damage of that bite attack increases by one step.
Craft Wondrous Item, alter self, resistance; Cost 1,250 gp.
Just a word on "primary natural attack". That means that, if it is the only attack you make, you get your full attack bonus and full STR bonus to hit and damage. However, you are probably more likely to attack with your teeth as part of the full round attack (it effectively gives you an additional attack as part of a full round attack) which makes it a "secondary natural attack". On that basis, your attack bonue with the bite is at -5 to your normal attack bonus and the damage is half your full STR damage bonus. These rules are summarised here.
"It is a small token, but hopefully useful."