Collation Setting Problem

[hamidsa]

<font face="Tahoma">I am developing an application with some php pages using directly vbulletin mysql database.
it queries some information and get users request for doing something in specified threads and finally close the thread which the user works is done by updating the field 'sticky' of its record in the thread table.
The question is 'By this update everything is fine or other changes must be done?'
another important question is the kind of approach storing data in mysql database tables records in other languages with varchar types.
in my application it is converted and shown like شرکت مهندسین مشاور جهد آزما which is forum title
how can i convert them this is also the thing I see them directly in mysql database the collation is set to utf8_unicode_ci from the first, by changing the same field to utf8_persian_ci and adding a tread it doesn't correct but the vbulletin itself shows them correctly </font>