For wills in the Antrim area in that period there are 3 possible indexes to search:-
Admons - (i.e. for administering estates where no valid will can be found) - for Co Antrim these are searchable free on the PRONI website for the period 1661-1857 - no "Denty"s found (but one "Francis Dent" in Antrim Admon granted 1729 - papers don't survive).
http://applications.proni.gov.uk/DCAL_PRONI_ProniNames/SearchPage.aspxDiocesan Wills - (before 1858 wills were proved in special courts of the Church of Ireland - Connor Diocesan court covered most of Co Antrim) Index available in printed books and I don't have access at the minute - It is available in Linenhall Library if you are near Belfast. Only a small percentage of the actual wills survive and this (smaller) list is also searchable on the PRONI site. This gives one positive result for 'James Denty of Cawnpore, India' whose will was proved in 1790. It can be accessed at PRONI when they re-open in April under reference D/651/D/IC/25.
Prerogative Wills - (i.e. large estates/property in more than one diocese) These were proved in a special court in Dublin and an index of those relating to Co Antrim is available on the Ancestry Ireland subscription site (I hope I'm not breaking any rules in telling you there are no Dentys listed)