a 27 year old Chinese, with J-1 visa in Palo Alto CA, asking for information
about cheap dental insurance for half a year, which can cover the root channel
treatment, teeth wash and teeth fillings. please list some related
general information about dental insurance too.

dental insurance is a hot topic and unfortunatley most dental plans
will not cover a Root canal therapy 100%.  You will have to get
insurance though one of the big companies such as Delta Dental, Blue
Cross Blue Shield, Athena, Guardian, etc.  Most of these companies
will pay 50-80% of a Root canal.  Your teeth cleaning are usually
covered 100% and fillings can be covered or can be 80% depending on
your plan.  If you only need it for a 6 months your best bet would be
to go to a dental school, they offer greatly discounted prices...at my
school in boston we charge:

Cleaning $40 (includes x-rays)
RCT $95 
You might need a crown with the RCT which costs ($400)
Fillings ($30-60)

I did a quick search and the following dental school is close to you:

University of the Pacific School...
(510) 489-5200	
1203 J St
Union City, CA 94587


Good luck & keep the smiling!