1 - Defeating StoneMan;
2 - Talk to the old man in front of the Metro. He lost his dentures,
3 - Head North-East to get to the park;
4 - Examine the Trees in the North-East corner to obtain the "Dentures"!;
5 - Head back to the old man and hand him his dentures. He will give you a "Recov80 G" chip as a reward;