Yes. A superior Wand such as a Dragontooth
can be enchanted with any Wand enchantment (Player's Handbook
3 pg. 195)
If you have a Flame Dragontooth Wand
and you already have Scorching Burst
power, it means you will have Scorching Burst
as an at-will wizard power and a Flame Dragontooth Wand
power working as Scorching Burst
as an encounter power. Not very useful in this case since you will already be able to produce this effect at-will.
Superior Implement: Despite their magical origin, superior Implements aren't magic item per se, but like non-superior implements. they can be enchanted with the Enchant Magic Item rital.