Type of drupal cache to be cleared on new hook implementation
If you look at the module_implements() function, it uses the following code to reset the hook cache:

cache_set('module_implements', array(), 'cache_bootstrap');
drupal_static_reset('module_hook_info');
drupal_static_reset('drupal_alter');
cache_clear_all('hook_info', 'cache_bootstrap');


You can just use the same code to do it yourself.