Efektifitas Ekstrak Biji Buah Alpukat (Persea americana Mill) dalam Menghambat Pelepasan Unsur Logam Kawat Ortodonti Berbahan Dasar Nikel Titanium
(The Effect of Avocado Seed Extract (Persea americana Mill) on Inhibiting the Release of Metal Elements in Nickel-Titanium-Based Orthodontic Wires)