Replying to the tourists' total of 328 all out off 50 overs, the home side were bundled out for just 142 off 39.2 overs, suffering their worst margin of defeat ever in a one-dayer against the English and being swept 3-0 by the same opponents for the first time since 1991.
Sidelined for almost two months by a hand injury sustained in India, Hales belted 110 on his return while Root followed up his assured match-winning 90 not out in the second game in Antigua with 101.
"This innings was really special because I wanted to get back into the thick of things," said man of the match Hales.
"It was frustrating being on the sidelines and I was desperately keen to perform."
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Seeking to avoid a whitewash in the series and needing rankings points to earn automatic qualification for the 2019 World Cup, the West Indies hardly helped their cause by extending the epidemic of dropped catches that afflicted them in the first two matches in Antigua.
Joseph, the 20-year-old Antiguan pacer who replaced injured fellow fast bowler Shannon Gabriel, claimed four expensive wickets but looked the most threatening after West Indies captain Jason Holder won the toss for the third consecutive time and chose to put England in.
He accounted for the attacking Jason Roy in just the sixth over of the innings and should have had more early success but for Lewis' costly error.
However if there was any encouragement from the bit of resistance towards the end of the innings, it all dissipated within the first four overs of the West Indies reply with the top three again succumbing to the England seamers.
Jonathan Carter top-scored with 46 in the middle-order but the match was long over as a contest with man of the series Chris Woakes and fellow fast-medium bowler Liam Plunkett taking three wickets each.
"This is extremely frustrating, we just didn't compete in this match," said a disconsolate Holder in reflecting on another embarrassing setback for his team.
"I thought we committed too many errors in the field and didn't bowl consistently well. We can only go forward from this.
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