If fungal debris is present in the ear canal even after using the antifungal ear drops,will there be a possibility of recurrence of the infection?

Possibly: There is always a possibility of recurrence of fungal infections due to re-exposure and possibly an innate susceptibility. There is no need to scrub your ear canals to remove "fungal debris" to reduce your risk. Simply keep your ear canals dry, keep your ear buds clean (possibly switch to over-the-ear style headphones), and see your physician for examination if you have any concerns.

Yes: An incompletely treated fungal otitis externa will continue to smoulder along. An otolaryngologist is best qualified to evaluate and treat this problem if it persists.

Always a chance.: The debris should be cleaned out by a professional. The debris is not necessarily infectious. So, it doesn't have to. HOWEVER, I've never had a patient wiht this that did NOT have trouble getting rid of the fungal infection because fungus can sit on top of the skin and not be hit by the treatment. Tricky to get rid of it.